CA2369954A1 - Method and composition for inhibiting corrosion in aqueous systems - Google Patents

Abstract

A method for controlling corrosion of metals, such as stainless steel, in contact with an aqueous system which comprises introducing into said system at least one tetrazolium compound of formula (I) wherein R1, R2 and R3 are selected from the group consisting of lower alkyl, branched lower alkyl, ary l, substituted aryl, alkylaryl, substituted alkylaryl and heterocyclic substituted aryl, with the proviso that neither R1, R2, or R3 contain more than 14 carbon atoms; and n is 1 or 2, such tetrazolium compound optionally having associated water soluble ionic species if needed to obtain a neutral charge.

Description

METHOD AND COMPOSITION FOR INHIBITING
CORROSION IN AQUEOUS SYSTEMS
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a Continuation-In-Part of Application No. 09/136,884, filed August 19, 1998, a Continuation-In-Part of Applicatmi~ No: (?9/303,596, filed May 3, 1999, and a Continuation-In-Part of Application No. 09/304,181, filed May 3, 1999. The disclosures of each of these applications is incorporated by reference in its entirety.
Metals are widely used in the construction of equipment associated with aqueous systems.
By "aqueous systems" it is meant any system containing metals which contain or are contacted with aqueous fluids on a regular basis. Water-based fluids are typically fluids that contain at least about 50 weight percent water, the remainder being solids (suspended and/or dissolved) and/or nonaqueous fluids. The term aqueous fluids is intended to include not only water-based fluids, but also fluids that are predominantly non-aqueous but have sufficient water present, at least about 5 weight percent water, so that water soluble treatment components may be effectively employed to limit corrosion. Such non-aqueous fluids may be miscible or immiscible with water.
Typical aqueous systems include, but are not limited to, open recirculating cooling systems which obtain their source of cooling by evaporation, closed loop cooling systems, boilers and similar steam generating systems, heat exchange equipment, reverse osmosis equipment, oil production systems, flash evaporators, desalinization plants, gas scrubbers, blast furnaces, paper and pulp processing equipment, steam power plants, geothermal systems, food and beverage processing equipment, sugar evaporators, mining circuits, bottle washing equipment, soil irrigation systems, closed circuit heating systems for residential and commercial use, aqueous-based refrigeration systems, down-well systems, aqueous machining fluids (e.g.
for use in boring, milling, reaming, broaching, drawing, turning, cutting, sewing, grinding and in thread-cutting operations, or in non-cutting shaping, spinning, drawing, or rolling operations), aqueous scouring systems, aqueous glycol anti-freeze systems, water/glycol hydraulic fluids, ferrous surface pre-treatment, polymer coating systems, and the like. Various types of water may be utilized in such systems, for example fresh water, brackish water, sea water, brines, sewage effluents, industrial waste waters, and the like.
The aqueous systems that may be treated using the compositions of this invention may contain dissolved oxygen, such as might be obtained from absorbing oxygen from ambient air, or they may be substantially or completely oxygen free. Further, the aqueous system may contain other dissolved gases such as carbon dioxide, hydrogen sulfide, or ammonia, or they maybe substantially or completely free of such gases.
There may be several different types of corrosion encountered in aqueous systems. For example, aqueous systems may have uniform corrosion over the entire metal surface. The aqueous system may also have localized corrosion, such as pitting or crevice corrosion, where the corrosion is found only in certain locations on the metal surface. Often, control of localized corrosion may be the critical factor in prolonging the useful life of the metal equipment in the aqueous system. In particular, aqueous systems which contain high levels of aggressive anions such as chloride and sulfate are particularly prone to both generalized and localized attack. These aggressive anions may be present in the water source used for the aqueous system at levels that cause problems, or they may be concentrated to harmful levels in the aqueous system because they are part of a system that evaporates water such as an evaporative cooling system.
Localized corrosion may pose even a greater threat to the normal operation of the system than general corrosion because such corrosion will occur intensely in one location and may cause perforations in the system structure carrying the fluid stream. Obviously, these perforations may cause leaks which require shutdown of the entire aqueous system so that repair can be made.
Indeed, corrosion problems usually result in immense maintenance costs, as well as costs incurred as a result of equipment failure. Therefore, the inhibition of metal corrosion in aqueous systems is critical.
In the descriptions that follow, we utilize the terms oligomer, polymer, co-oligomer, and co-polymer. By oligomer we mean materials produced by the polymerization of a single monomer where the number of monomer units incorporated in the product is between 2 and about 10. By polymer, we mean materials produced by the polymerization of a single monomer without restriction on the number of monomer units incorporated into the product. By co-oligomer, we mean materials produced by the polymerization of more than one type of monomer (including 2, 3, 4, etc. different monomers) where the total number of monomer units incorporated in the product is between 2 and about 10. By co-polymers, we mean materials produced by the polymerization of more than one type of monomer (including 2, 3, 4, etc.
different monomers) without restriction on the number of monomer units incorporated into the product.
In aqueous systems, the following corrosion reactions of metals, such as steel, occur:

Fe O FezT + 2e Fe (0H)2 + OH- O Fe (0H)3 + a When tetrazolium compounds possessing redox potentials higher than that of the corroding metals or alloys are employed, reduction of tetrazolium molecules readily occurs on the metal, e.g., steel or stainless steel surface to form insoluble materials and, hence, prevent steel from further corrosion.
The method of the present invention comprises treating industrial waters with a tetrazolium salt of the general formula:
to N N+
N
~ N
R3 R2 n wherein R,, Rz and R3 can be various organic and inorganic substituents, e.g., from the group consisting of lower alkyl, aryl, aralkyl, and heterocyclic substituted aryl with the proviso that neither R,, RZ or R3 contain more than 14 carbon atoms, and n may be 1 or 2.
The compounds may contain positive or negative counter ions in order to balance the charges on the above structure. Chemical or electrochemical reduction of this type of compound produces tetrazolinyls and fortnazans that readily adsorb on metal surfaces and provide films for corrosion protection.
We have also discovered that certain tetrazolium compounds given by the generalized formula:

N N+
s N
~N
R3 R2 n wherein R~, RZ and R3 can be various organic and inorganic substituents, e.g., from the group consisting of lower alkyl, branched lower alkyl, aryl, substituted aryl, alkylaryl, substituted alkylaryl and heterocyclic substituted aryl with the proviso that none of Rl, RZ or R3 contain more than 14 carbon atoms, and n may be 1 or 2, synergistically combine with a wide range of compounds to provide effective general and localized corrosion protection for metals in aqueous systems. If the components chosen to be combined with the tetrazolium compounds are also scale 1 s and/or deposition inhibitors, the combinations will also provide scale and/or deposition inhibition for these aqueous systems.
Anions and/or canons may be associated with the above structure to balance the charge depending upon the substitutions employed. If R,, R, and R3 are all neutral, then the structure shown in the above formula will be positively charged and anionic species will be needed.
The anions and/or cations utilized for balancing can be any such anions and/or canons, such as halogens, nitrates, nitrites, carbonates, bicarbonates, sulfates, phosphates, and transition metal oxygenates.
Anions and/or cations may be associated with the above structure to balance the charge depending upon the substitutions employed. If R~, R, and R3 are all neutral, then the structure 2s shown in the above formula will be positively charged and anionic species will be needed. For example, the tetrazolium compounds according to the present invention are neutral. In the simplest case, if all of R,, Rz and R3 are neutral, then a counter ion that is an anion with a single negative charge, e.g., Cl-, will be needed to balance change for n=1. For n=2, then two anions, each with a single negative charge or one anion with a double negative charge, e.g., S04 2, would be needed to balance the charge. Moreover, for example, the charge associated with R,, Rz and R3 is not neutral, such as if the groups included sulfono, carboxyl and/or quaternary nitrogen, associated counter-ions should be present to provide a neutral charge for the tetrazolium compound. Thus, for example, if n=2, and R, is substituted with a single carboxyl group (COO-), then the tetrazolium compound could be a zinc chloride salt wherein the Znl2 neutralizes the two carboxyl charges and the CI- neutralizes the positive charge of the two ring nitrogens.
Examples of such tetrazolium compounds that may be utilized according the this invention include Nitroblue Tetrazolium chloride (3,3'-(3,3'-Dimethoxy-4,4'-biphenylene)-bis-[2-p-nitrophenyl-5-phenyl-2H-tetrazolium chloride]), hereafter referred to as NBT, Distyryl Nitroblue Tetrazolium Chloride (2,2'-Di-p-nitrophenyl-5,5'-distyryl-3,3'-[3,3'-dimethoxy-4,4'-biphenylene] ditetrazolium chloride), hereafter referred to as DNBT, Tetranitroblue Tetrazolium chloride (3,3'-(3,3'-Dimethoxy-4,4'-biphenylene)-bis-[2,5-p-nitrophenyl-2H-tetrazolium chloride]), hereafter referred to as TNBT, and Iodonitro tetrazolium chloride (2-(4-Iodophenyl)-3-(4-nitrophenyl)-5-phenyltetrazolium chloride) hereafter referred to as INT.
The metals in the aqueous system can be any metal for which corrosion and/or scaling can be prevented. For example, the metal can be non-ferrous metals, such as copper, aluminum, or ferrous metals, such as iron, steel, e.g. low carbon steel, and stainless steel, e.g. iron based alloys containing chromium as the main alloying element, such as steels containing between about 11 to 30% Cr, which exhibit excellent corrosion resistance to many environments.
The present invention provides particularly beneficial results in that even when the tetrazolium compound is utilized by itself without the addition of other materials, including other anti-corrosion and/or scale prevention ingredients, low concentrations of the tetrazolium compounds can be utilized. This is especially the situation when the tetrazolium compounds are utilized in aqueous systems, in the presence of oxygen, wherein the pH of the system to be treated is about 6 or greater, such as cooling water systems, steam generating systems, gas scrubbing systems, and pulping and papermaking systems.
The tetrazolium compounds of the present invention can preferably be added to the aqueous system at active treatment levels ranging from about 0.1 to about SO
parts per million, with treatment levels of from about 1 to about 25 parts per million being particularly preferred.
In one preferred aspect, the present invention is directed to methods for controlling corrosion of stainless steel in contact with an aqueous system which comprises introducing into said system at least one tetrazolium compound of the formula:

Ri N N+
s N
'N
R3 R2 n wherein R~, RZ and R3 are selected from the group consisting of lower alkyl, branched lower alkyl, aryl, substituted aryl, alkylaryl, substituted alkylaryl and heterocyclic substituted aryl, with the proviso that neither R,, Rz, or R3 contain more than 14 carbon atoms; and n is 1 or 2, such tetrazolium compound optionally having associated water soluble ionic species if needed to obtain a neutral charge.
The aqueous system can include at least one other aqueous system treatment material chosen so that the material does not substantially reduce the tetrazolium compound. Such material can be added with the tetrazolium compound or separately therefrom.
The other aqueous system treatment material is selected from the group consisting of inorganic phosphates, borates, nitrites, compounds that release a metal anion in water, 2,3-dihydroxybenzoic acid, 1,10-phenanthroline, polycarboxylates, hydrocarbyl polycarboxylates, alkyl hydroxycarboxylic acids, aminohydroxysuccinic acids, carboxyamines, polyepoxysuccinic acids, modified polyepoxysuccinic acids, monophosphonic acids, diphosphonic acids, phosphonocarboxylic acids, hydroxyphosphonocarboxylic acids, aminophosphonic acids, phosphonomethylamine oxides, polymeric amine oxides, polyetherpolyaminomethylene 2s phosphonates, polyetherpolyamino-methylene phosphonate N-oxides, iminoalkylenephosphonic acids, long chain fatty acid derivatives of sarcosine; telomeric, co-telomeric, polymeric, or copolymeric phosphorus-containing carboxylates, alkali metal silicates, monofluorophosphate, amines, diamines, alkanolamines, ether amines, fatty amines and diamines, quaternized amines, oxyalkylated amines, alkyl pyridines, tetrazoles, imidazoline and substituted imidazolines, amidoamines, polyamines, polyalkylenepolyamines, alkyl derivatives of benzene sulfonic acid, benzoates and substituted benzoates, aminobenzoates, salicylates, dimer-trimer acids, petroleum oxidates, borogluconates; lignins, lignosulfonates, tannins; straight chain CS-C" monocarboxylates and C4-C15 a,w-dicarboxylates; amine salts of carboxylic acids and mercaptocarboxylic acids, amino acids, polyamino acids, hydroxyether acids and related lactone compounds, N-acyliminodiacetic acids; triazine di- and tri-carboxylic acids, phospho- and phosphate esters; and monofluorophosphates; water soluble salts thereof, and mixtures thereof.
Moreover, as noted above, the present invention also provides beneficial results when combined with other compounds, such as compounds disclosed in U.S. Patent Application Nos.
09/136,884, filed August 19, 1998, 09/303,596, filed May 3, 1999, 09/304,181, filed May 3, 1999, and 09/309,564, filed May 12, 1999, the disclosures of which are incorporated by reference herein.
Examples of compounds that may be combined with the tetrazolium compounds to provide synergistically improved corrosion protection include: inorganic phosphates, such as orthophosphates or polyphosphates, borates, nitrites, and compounds that release a metal anion in water, where the metal anion is selected from the group consisting of molybdates, tungstates, vanadates, metavanadates, chromates or mixtures thereof.
The inorganic phosphates can include orthophosphates, polyphosphates, water soluble salts thereof and mixtures thereof, such as a mixture of orthophosphoric acid and pyrophosphoric acid or the water-soluble salts thereof, such as the sodium and potassium salts thereof.
The borates can comprise various borates, such as water-soluble borate selected from tetraborates, metaborates, and/or orthoborates, such as sodium tetraborate or a hydrate of sodium tetraborate.
The nitrates can include nitrites such as sodium nitrite.
Additional materials that may be combined with the tetrazolium compounds include polyacrylic acid or polymaleic acid, such as disclosed in the above-noted U.S.
Application No.
09/304,181, filed May 3, 1999. Particularly preferred polyacrylic and polymaleic acids have a molecular weight of about 8,000 or below.
Additional materials that may be combined with the tetrazolium compounds include polycarboxylates. The polycarboxylates may be simple aliphatic compounds containing between 4 and about 20 carbon atoms in the aliphatic chain which are multiply substituted with carboxyl groups (e.g., Cg-C,5 a,w-dicarboxylates or compounds such as l, 2, 3, 4-butanetetracarboxylic acid) or water soluble salts thereof, or may be polymeric compounds. The polymeric polycarboxylates may be homopolymers or copolymers (including terpolymers, tetrapolymers, etc.) of ethylenically unsaturated monomers that contain a carboxyl group. The polycarboxylates can comprise a copolymer obtained from the polymerization of two or more different ethylenically -unsaturated monomers, each of the monomers containing one or more carboxyl groups.
Examples of such polymeric polycarboxylates include polyacrylic acid, polymaleic acid, and polymaleic anhydride, and their water soluble salts. Additionally, the polycarboxylates may be hydrocarbyl polycarboxylates as disclosed in U.S. Patent 4,957,704, herein incorporated by reference.
Additional materials which may be combined with the tetrazolium compounds of the present invention include alkyl hydroxycarboxylic acids or a mixture of such alkyl hydroxycarboxylic acids having the formula:
HOOC -(Rs~)a ( Raz)b (Rs3)~ - Rsa where a, b, and c are integers from 0 to 6 and (a+b+c)>0 where RB,, RBZ, RB3 comprise C=O or CYZ, where Y and Z are separately selected from the group of H, OH, CHO, COOH, CH3, CHz(OH), CH(OH)z, CHz(COOH), CH(OH)COOH, CHz(CHO) and CH(OH)CHO, so selected that the molecule has a minimum of one OH group when written in its fully hydrated form and RB4 is either H or COOH, including the various stereoisomers and chemically equivalent cyclic, dehydrated, and hydrated forms of these acids and hydrolyzable esters and acetals that form the above compounds in water or the water soluble salts of such alkyl hydroxycarboxylic acids.
Examples of such hydroxycarboxylic acids include tartaric acid, mesotartaric acid, citric acid, gluconic acid, glucoheptonic acid, ketomalonic acid and saccharic acid, and their water soluble salts.
Additional materials which may be combined with tetrazolium compounds include aminohydroxysuccinic acid compounds (or mixtures of such aminohydroxysuccinic acid compounds) such as those disclosed in U.S. Patent 5,183,590, herein incorporated by reference.
Suitable aminohydroxysuccinic acids include those selected from the group consisting of compounds of the generalized formulas:
ci R N COZH
cz HO ~COZH
_g_ wherein Rc, is H or C, to C4 alkyl, optionally substituted with -OH, -COZH, -S03H, or phenyl, C4 to C, cycloalkyl, or phenyl which is optionally substituted with -OH or -COZH, and R~2 is H, C, to C6 alkyl, optionally substituted with -OH or -COZH
(specifically including the moiety -CH(COZH)CH(OH)(COZH)) ; and ~2 ~2 HOZC N Zc N C02H
HOZC ~OH HO COZH
wherein R~z is as above, and Z~ is selected from the group consisting of i) (CHz)k wherein k is an integer from 2 to 10, ii) -(CHz)z Xc-(CHZ)2 wherein Xc is -O-, -S-, NR~3 , wherein R~3 is selected from the group consisting of H, C1 to C6 alkyl, hydroxyalkyl, carboxyalkyl, acyl, -C(O)OR~4 wherein Rc4 is selected from the group consisting of C, to C6 alkyl or benzyl and a residue having the general formula:
Rcz HO COZH
wherein R~2 is as above, iii) a residue having the generalized formula:
Y
P
- (CH2)m ~ (CH2)m wherein Y is H, C, to C6 alkyl, alkoxy, halogen, - COzH, - S03H, m is independently 0 or 1, and p is 1 or 2, and (iv) a residue having the generalized formula:

(Q)s (CHZ)q (CRc5Rc6)t (CHZ)r (CRCSRC6)t wherein R~5 and R~6 are independently H or C, to C6 alkyl, Q is H or C1 to C6 alkyl, s is 0, 1 or 2, t is independently 0, 1, 2, or 3, q is 0, l, 2, or 3, and r is 1 or 2 or water soluble salts thereof.
Preferred examples of such aminohydroxysuccinic acid compounds include iminodi(2-hydroxysuccinic acid), N,N'-Bis(2-hydroxysuccinyl)-1,6-hexanediamine, and N,N'-Bis(2-hydroxysuccinyl)-m-xylylenediamine, or the water soluble salts thereof. It is preferred to utilize a mixture of orthophosphric acid or its water soluble salts with a least one aminohydroxysuccinic acid.
Additional materials which may be combined with the tetrazolium compounds include the carboxyamine compounds which are reaction products of carboxylating agents such as epoxysuccinic acid with amines comprising a plurality of nitrogen atoms such as polyethylene 1 S polyamines as disclosed in the International Patent Application WO
96/33953, herein incorporated by reference.
Additional materials which may be combined with the tetrazolium compounds include polyepoxysuccinic acids (referred to as PESAs) of the general formula:
RT RT
HO -~ C C O ~-- H
I

where 1 ranges from about 2 to about S0, preferably 2 to 25; MT is hydrogen or a water soluble cation such as Na+, NH4+, or K+ and Rr is hydrogen, C1_4 alkyl or C,_4 substituted alkyl (preferably RT is hydrogen). Preferably RT is hydrogen, and 1 ranges from about 2 to about 10, or from about 4 to about 7. The use of PESAs in treating aqueous systems has been disclosed in U.S. Patents 5,062,962 and 5,344,590, each herein incorporated by reference. A corrosion inhibition process utilizing a combination of an orthophosphate, a polyepoxysuccinic acid, an acrylic acid/allyl hydroxy propyl sulfonic acid polymer, and an azole has been disclosed in U.S.
Patent 5,256,332, herein incorporated by reference. Preferred mixture include a mixture of orthophosphoric acid and/or its water soluble salts and polyepoxysuccinic acid.
Modified polyepoxysuccinic acids of the general formula:

RDA ZD--j-C C O~H
a f MDOZC COZMD
wherein RD,, when present, is H, a substituted or non-substituted alkyl or aryl moiety having a carbon chain up to the length where solubility in aqueous solution is lost, or a repeat unit obtained after polymerization of an ethylenically unsaturated compound; RDZ
and RD3 each independently are H, C~ to C4 alkyl or CI to C4 substituted alkyl; ZD is O, S, NH, or NRD,, where RDl is as described above, a is a positive integer greater than l; f is a positive integer; and MD is H, a water soluble cation (e.g., NH4+, alkali metal), or a non-substituted lower alkyl group having from 1 to 3 carbon atoms (when RDA is not present, ZD may be MD03S, where MD
is as described above) may also be effectively combined with the tetrazolium compounds of the present invention.
Use of such compounds have been disclosed in U.S. Patents 5,871,691 and 5,489,666, herein incorporated by reference. Examples of such modified polyepoxysuccinic acids include derivatives according to the above formula where RD, is meta-CHZ-C6H4-CHZ- (m-Xylylene), ZD
is -NH-, both RDZ and RD3 are H, f is 2, and MD is Na or H. Practical examples are typically mixtures where the individual molecules have a range of u, and are hereafter referred to as m-Xylylenediamine/PESA derivatives.
Additional compounds that may be combined with the tetrazolium compounds include 2,3-dihydroxybenzoic acid and 1,10-phenanthroline.
Additional compounds that may be combined with the tetrazolium compounds include monophosphonic acids having the generalized formula:
II/OH
RF P
OOH

wherein RF is a C~ to C~Z straight or branched chain alkyl residue , a CZ to C~2 straight or branched chain alkenyl residue, a CS to C1z cycloalkyl residue, a C~ to Coo aryl residue, or a C~ to C,2 aralkyl residue, and where RF may additionally be singly or multiply substituted with groups independently chosen from hydroxyl, amino, or halogen; and diphosphonic acid compounds having the generalized formula:
HO~II II/OH
P RK P
HO ~ OH
wherein RK is a C, to C12 straight or branched chain alkylene residue, a C Z
to C l2 straight or branched chain alkenylene residue, a CS to C,Z cycloalkylene residue, a C6 to C,o arylene residue, or a C~ to C~2 aralkylene residue where RK may additionally be singly or multiply substituted with groups independently chosen from hydroxyl, amino, or halogen, or water soluble salts thereof.
A preferred example of such a diphosphonic acid is 1-hydroxyethane-l,l-diphosphonic acid (HEDP) or water soluble salts thereof.
Additional materials which may be combined with the tetrazolium compounds include phosphonocarboxylic acids (or mixtures of such phosphonocarboxylic acids) such as those disclosed in U.S. Patents 3,886,204, 3,886,205, 3,923,876, 3,933,427, 4,020,101 and 4,246,103, all herein incorporated by reference. Preferred are those phosphonocarboxylic acids defined by the following generalized formulas:
HO~
P C COOH
HO CHZ COOH
and O H
HO ~ ~I
/ P H C COOH
HO
CHZ COOH

where RH1 is H, alkyl, alkenyl, or alkinyl radical having 1 to 4 carbon atoms, an aryl, cycloalkyl, or aralkyl radical, or the radical selected from the following:

CH CHZ COOH and CH CH COOH
where R~ is H, alkyl radical of 1 to 4 carbon atoms, or a carboxyl radical;
and X~, is selected from the following:
COOH ~H P03H2 COOH P03Hz - ~ ~ , - ~ ~ CH ~ C ~ and C-~3 ~3 and where the -P03Hz group is the phosphono group II/OH
P
~ OH
or water-soluble salts thereof. An example of such a preferred phosphonocarboxylic acid is 2-phosphonobutane-1,2,4-tricarboxylic acid, or water soluble salts thereof.
Additional materials which may be combined with the tetrazolium compounds include hydroxyphosphonocarboxylic acids (or mixtures of such hydroxyphosphonocarboxylic compounds) such as those disclosed in U.S. Patents 4,689,200 and 4,847,017, both herein incorporated by reference. Suitable hydroxyphosphonocarboxylic acids includes those having the generalized formula:

HO ~ II
P C XE COOH
Hod I
OH
S wherein RE is H, a C, to C,Z straight or branched chain alkyl residue, a Cz to C ,z straight or branched chain alkenyl residue, a CS to C,Z cycloalkyl residue, a C6 to Clo aryl residue, or a C~ to C,Z aralkyl residue, XE is an optional group, which when present is a CI to CIO straight or branched chain alkylene residue, a CZ to C,o straight or branched chain alkenylene residue, or a C6 to Clo arylene residue or water soluble salts thereof. A preferred example of such a hydroxyphosphonocarboxylic acid is 2-hydroxy-phosphonoacetic acid, or water soluble salts thereof.
Additional materials which may be combined with the tetrazolium compounds include aminophosphonic acids such as those disclosed in U.S. Patents 3,619,427, 3,723,347, 3,816,333, 4,029,696, 4,033,896, 4,079,006, 4,163,733, 4,307,038, 4,308,147 and 4,617,129, all herein incorporated by reference. Suitable aminophosphonic acids include those having the generalized formula:
RG\ I I / off RGZ P~
OH

where RGZ is a lower alkylene having from about one to about four carbon atoms, or an amine, hydroxy, or halogen substituted lower alkylene; R~3 is R~Z P03H2, H, OH, amino, substituted amino, or RF as previously defined; R~4 is R~3 or the group represented by the generalized formula:
GS O
OH
C N RGz OH

where R~5 and R~6 are each independently chosen from H, OH, amino, substituted amino, or RF
as previously defined; RG~ is RGS, R~6, or the group RGZ P03Hz with R~Z as previously defined;

v is an integer from 1 to about 15; and w is an integer from 1 through about 14 or water soluble salts thereof. An example of such an aminophosphonic acid is diethylenetriamine penta(methylenephosphonic acid), or water soluble salts thereof.
Additional materials which may be combined with the tetrazolium compounds include water soluble phosphonomethyl amine oxides (or mixtures of such water soluble phosphonomethyl amine oxides) such as those disclosed in U.S. Patents 5,051,532, 5,096,595, and 5,167,866, all herein incorporated by reference. Suitable phosphonomethyl amine oxides include those having the generalized formula:
RA' O
N CHzPQ3Hz wherein either RA, is selected from the group consisting of hydrocarbyl, and hydroxy-substituted, alkoxy-substituted, carboxyl-substituted and sulfonyl-substituted hydrocarbyl;
and R,~ is selected from the group consisting of hydrocarbyl, and hydroxy-substituted, alkoxy-substituted, carboxyl-substituted and sulfonyl-substituted hydrocarbyl, CHZP03H2, and O
GzHa N ( ~zP~Hz) z ' or RAE and R,~ together form an alicyclic ring having 3 to 5 carbon atoms in the ring or a water soluble salt of said phosphonomethyl amine oxide. Hydrocarbyl includes alkyl, aryl, and alkaryl groups which do not render the amine oxide insoluble in water. A preferred example of such a phosphonomethylamine oxide is N,N-bis-phosphonomethylethanolamine N-oxide, hereafter referred to as EBO, or water soluble salts thereof.
Additional materials which may be combined with the tetrazolium compounds include polymeric amine oxides as described in U.S. Patent 5,629,385, herein incorporated by reference, polyether polyaminomethylene phosphonates and polyether polyamino methylene phosphonate N-oxides, as described in U.S. Patents 5,338,477 and 5,322,636, respectively, both herein incorporated by reference, and iminoalkylenephosphonic acids, as described in U.S. Patent 5,788,857, herein incorporated by reference.

Additional materials which may be combined with the tetrazolium compounds include phosphorus-containing carboxylate materials (hereafter, P-carboxylates) which are telomeric, co-telomeric, polymeric or co-polymeric compounds that include at least one organic phosphorus group and multiple carboxylate groups. Optionally, these materials may also include other substituent groups when the P-carboxylates are produced from monomers which contain substituents other than carboxylate. The phosphorus may be present as an end group, in which case it may be a phosphono or end-type phosphino-type moiety, or may be incorporated into the compound as a phosphino moiety in which the phosphorus is directly bonded to two carbon atoms, a configuration sometimes referred to as a "dialkyl" phosphino moiety. These possibilities are shown schematically below .
O O O
Y O PI C ~r H IP C ~. ~~ C IP C ", O O
X X X
PHOSPHONO END-TYPE PHOSPHINO DIALKYL-TYPE
PHOSPHINO
X may be hydrogen or a cationic species such as an alkali metal ion, an ammonium ion, or a quaternized amine radical. Y may be the same as X or additionally may be a substituted or non-substituted alkyl, aryl, or alkylaryl residue, where the substitutions may or may not contain carboxylate. Y must be chosen so as to maintain adequate solubility of the compound in water.
The carbon atoms shown are part of the carbon backbone of the telomer, co-telomer, polymer, or co-polymer, this backbone containing at least two carboxyl groups and optionally other phosphorus incorporations and optionally other non-carboxyl substitutions.
Preferred are P-carboxylates having number average molecular weights under 10,000, and particularly preferred are oligomeric or polymeric P-carboxylates of low number average molecular weight, e.g., 2,000 or less, and especially 1,000 or less. It is particularly preferred that 2 or more carboxylates are substituted on a linear alkyl residue, in order of preference, in a 1,2-(adjacent) or a 1,3-substitution arrangement. The P-carboxylates may contain the phosphorus substitution or substitutions predominantly or exclusively as phosphono species, predominantly or exclusively as end-type phosphino species, predominantly or exclusively as dialkylphosphino species, or contain a mixture of these substitution types on an individual molecule and/or in the mixture of molecules generated by a particular preparative process. The various preparative processes used for P-carboxylates may also generate various inorganic phosphorus species as part of the synthetic process. Such mixtures of P-carboxylates and the associated inorganic phosphorus species when combined with tetrazolium compounds are considered to be within the scope of this invention.
Non-limiting examples of the preparation of P-carboxylates suitable for use in this invention and their use as corrosion and/or scale control agents alone and in combination with other water treatment agents in aqueous systems are disclosed in U.S. patents 2,957,931, 4,046,707, 4,088,678, 4,105,551, 4,127,483, 4,159,946, 4,207,405, 4,239,648, 4,563,284, 4,621,127, 4,681,686, 5,023,000, 5,073,299, 5,077,361, 5,085,794, 5,160,630, 5,216,099, 5,229,030, 5,256,302, 5,256,746, 5,294,687, 5,360,550, 5,376,731, 5,386,038, 5,409,571, 5,606,105, 5,647,995, 5,681,479, and 5,783,728 and European Patents 283191A2, 360746B1, 569731A2, 681995A3, 786018A1, 792890A1, 807635A1, 807654A2, and 861846A2, all herein incorporated by reference. As may be appreciated by examination of these patents, a variety of preparative processes are suitable for producing P-carboxylates useful for this invention. It is not the object of this invention to specify any particular process or method for making the P-carboxylates suitable for use in this invention. In general, they may be produced by reacting a phosphorus containing material with one or more polymerizable monomers, at least one of which contains carboxyl groups or groups which can be made to generate a carboxyl in the final compound (after the polymerization process) by further reactions such as hydrolysis, oxidation, and the like, such monomers being hereafter referred to as carboxyl monomers.
The processes disclosed in the art typically involve reaction of a phosphorus-containing material with one or more unsaturated monomers, at least one of which is a carboxyl monomer, to generate P-carboxylate oligomers or polymers. Examples of suitable carboxyl monomers include acrylic acid, malefic acid, malefic anhydride, methacrylic acid, itaconic acid, crotonic acid, vinyl acetic acid, fumaric acid, citraconic acid, mesaconic acid, acrylonitrile, methacrylonitrile, alpha-methylene glutaric acid, cyclohexenedicarboxylic acid, cis-1,2,3,6-tetrahydrophthalic anhydride, 3,6-epoxy-1,2,3,6-tetrahydrophthalic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, bicyclo[2.2.2)-5-octene-2,3-dicarboxylic anhydride, 3-methyl-1,2,6-tetrahydrophthalic anhydride, and 2-methyl-1,3,6-tetrahydrophthalic anhydride. Preferred carboxyl monomers are acrylic acid, malefic acid, itaconic acid, and malefic anhydride.

Although it is preferred that P-carboxylate materials contain a major proportion of residues that bear carboxyl groups, it may be advantageous to utilize co-oligomeric or co-polymeric P-carboxylates that contain residues that are derived from at least one carboxyl monomer and a minor proportion (under SO percent by weight of the total product) of residues obtained from at least one other monomer that is not a carboxyl monomer. A wide variety of suitable non-carboxyl monomers exist, including, for example, 2-acrylamido-2-methylpropanesulfonic acid (commercially available as AMPSTM from the Lubrizol Corporation), 2-hydroxy-3-(2-propenyloxy)propanesulfonic acid, 2-methyl-2-propene-1-sulfonic acid, allylsulfonic acid, allyloxybenzenesulfonic acid, styrenesulfonic acid, vinylsulfonic acid, allylphosphonic acid, vinylphosphonic acid, isopropenylphosphonic acid, phosphoethyl methacrylate, hydroxyalkyl and C,-C4 alkyl esters of acrylic or methacrylic acid, acrylamides, alkyl substituted acrylamides, allyl alcohol, 2-vinyl pyridine, 4-vinyl pyridine, N-vinylpyrrolidone, N-vinylformamide, N-vinylimidazole, vinyl acetate, hydrolyzed vinyl acetate, and styrene.
Specifically included within the category of P-carboxylates are phosphonic polymers having the generalized formula:
II /Ox, RJ ~ P
~OXJ
wherein X~ is H, an alkali metal atom, an alkaline earth metal atom, or an ammonium or amine residue; and R~~ is a copolymer residue comprising two different residues -E- CH2 CH (R~2) -~-wherein z is an integer ranging from 2 to 100, and wherein, in the first residue, RJZ is -COOH, and in the second residue, RJZ is -CONHC(CH3)ZCHZSO3XJ, wherein Xf is as hereinbefore defined.
Non-limiting examples of P-carboxylate materials suitable for use in this invention include Belsperse 161, Belclene 400, Belclene 494. Belclene 500 (all commercially available products of FMC corporation), phosphonosuccinic acid, and Bricorr 288 (a product of Albright and Wilson).
Bricorr 288 is described as a composition which consists essentially of up to 50% by weight of a phosphonosuccinic acid, based on the weight of the composition, a phosphonated dimer of alkali metal maleate, not more than a minor proportion by weight, based on the weight of the dimer, of higher phosphonated oligomers of maleate; and from about 0.5 to about 5% by weight of the composition of an alkali metal phosphate.
Additional materials which may be combined with the tetrazolium compounds include long chain fatty acid derivatives of sarcosine (or mixture of such fatty acid sarcosine derivatives) or their water soluble salts. An example of such a derivative is N-Lauroylsarcosine.
The tetrazolium compounds of this invention may also be combined with water soluble alkali metal silicates, such as sodium metasilicate. Such silicates are well known in the art as corrosion inhibitors for both ferrous metals and aluminum, both in systems where the fluid is predominantly water as well as in glycol-based aqueous systems typically used as antifreeze coolants for internal combustion engines. The sodium silicates may be represented generically by the formula NazO~xSi02~yHzO where x is in the range of about 1 to about 3.5. Commercial sodium silicate solutions in which the mole ratio of silica to soda is about 3.3 may be used. More alkaline solutions having an Si02: Na20 mole ratio as low as about 1:1 or less alkaline solutions having a an SiOz:NazO mole ratio up to about 3.5:1 can also be used. Other alkali metal silicate salts, especially potassium silicate may also be employed. When using water soluble alkali metal silicates in the practice of the current invention, it may be advantageous to combine the silicates with other inhibitors and/or silica stabilizers. Examples of such suitable combinations are disclosed in U.S. Patents 3,711,246, 4,085,063, 4,404,114, 5,137,657, 5,262,078, 5,578,246, and 5,589,106, all herein incorporated by reference.
The tetrazolium compounds of this inventions may also be combined with water soluble monofluorophosphate salts. The use of such salts as corrosion inhibitors for metallic surfaces has been disclosed in U.S. Patents 4,132,572 and 4,613,450, both herein incorporated by reference.
As disclosed in U.S. Patent 5,182,028, herein incorporated by reference, such salts also have utility for calcium carbonate scale control and in iron and manganese stabilization.
A wide variety of additional aqueous system corrosion inhibitors suitable for combination with the tetrazolium materials in this invention are known in the art. Non-limiting examples of such inhibitors may be found in Corrosion Inhibitors, C.C. Nathan, ed., NACE, 1973; LL.
Rozenfeld, Corrosion Inhibitors, McGraw-Hill, 1981; Metals Handbook, 9''' Ed., Vol. 13 -Con osion, pp. 478-497; Con osion Inhibitors for Corrosion Control, B.G.
Clubley, ed., The Royal Society of Chemistry, 1990; Corrosion Inhibitors, European Federation of Corrosion Publications Number 11, The Institute of Materials, 1994; Corrosion, Vol. 2 - Corrosion Control, L.L. Sheir, R.A. Jarman, and G.T. Burstein, eds., Butterworth-Heinemann, 1994, pp. 17:10-17:39; Y.I.

Kuznetsov, Organic Inhibitors of Corrosion of Metals, Plenum, 1996; and in V.S. Sastri, Corrosion Inhibitors: Principles and Applications, Wiley, 1998. Such inhibitors include amines (e.g., morpholine, cyclohexylamine, benzylamine), alkanolamines, ether amines, diamines, fatty amines and diamines, quaternized amines, oxyalkylated amines, alkyl pyridines;
tetrazoles such as those disclosed in U.S. patent 5,744,069, herein incorporated by reference;
imidazoline and substituted imidazolines, amidoamines, polyamines, including polyalkylenepolyamines such as those disclosed in U.S. patent 5,275,744, herein incorporated by reference, alkyl derivatives of benzene sulfonic acid, benzoates and substituted benzoates (e.g., p-tert-butylbenzoic acid as disclosed in U.S. patent 5,275,744, herein incorporated by reference), aminobenzoates, salicylates, dimer-trimer acids, petroleum oxidates, borogluconates; lignins, tannins, and the sulfonated and/or carboxylated derivatives thereof (e.g., lignosulfonates); straight chain CS-C, ~ monocarboxylates, amine salts of carboxylic acids and mercaptocarboxylic acids such as those disclosed in U.S.
Patent 5,779,938, herein incorporated by reference; amino acids, polyamino acids, and derivatives thereof such as those disclosed in U.S. Patents 4,971,724, 5,531,934, 5,616,544, 5,750,070, and 5,785,896 herein incorporated by reference; hydroxyether acids and related lactone compounds such as those disclosed in U.S. Patent 5,055,230 herein incorporated by reference, N-acyl sarcosines, N-acyliminodiacetic acids; triazine di- and tri-carboxylic acids such as those disclosed in U.S. 4,402,907, herein incorporated by reference, and phospho- and phosphate esters (e.g., of ethoxylated alcohols) such as those disclosed in U.S. Patents 3,873,465, 3,932,303, 4,066,398, and 5,611,991, herein incorporated by reference.
In the practice of this invention it may be advantageous to employ additional agents to enhance or add additional functionality to the combinations of this invention.
Suitable additional agents include dispersants, copper corrosion inhibitors, aluminum corrosion inhibitors, water soluble metal salts and their chelates, scale and deposit control agents, sequestering agents, anti-foams, oxidizing and non-oxidizing biocides, non-ionic and ionic freezing point depressants, pH
adjusting agents, inert and active tracers, water insoluble and soluble lubricants, surfactants, calcium hardness adjusting agents, and coloring agents.
Dispersants are often needed to maintain system cleanliness when the aqueous system contain suspended particulate matter. A wide variety of polymeric and non-polymeric dispersants are known in the art which may be used in the practice of this invention.
Preferred are a) water-soluble sulfonated polymers or copolymers obtained from the polymerization of one or more ethylenically unsaturated monomers, at least one of which contains sulfonate functionality, or the w0 00/66810 PCT/US00/08750 water soluble salts thereof or b) copolymers of diiosbutylene and malefic anhydride with molecular weights < 10,000 or the water soluble salts thereof. Particularly preferred is about a 3:1 weight ratio copolymer of acrylic acid and allyl hydroxy propyl sulfonate ether or the water soluble salts thereof.
Additional agents that may be combined with the tetrazolium compounds of this invention include copper corrosion inhibitors, including heterocyclic ring type copper inhibitors such as azole compounds. As is well known in the art, azoles are typically used to provide corrosion protection for copper-based alloys. However, as is also known in the art, in certain systems azoles and similar heterocyclic ring type copper inhibitors additionally provide corrosion protection for ferrous-based metals and/or aluminum, and the use of such materials for these purposes is considered to be within the scope of this invention. As one skilled in the art may readily appreciate, the use of copper inhibitors in the practice of this invention may enhance the performance of the compositions of this invention in protecting a particular metal system and/or may extend the applicability to multi-metal systems.
Suitable azole compounds include triazoles, tetrazoles, pyrazoles, imidazoles, isoxazoles, oxazoles, isothiazoles, and thiazoles, all optionally substituted with alkyl, aryl, aralkyl, alkylol, and alkenyl radicals, including those disclosed in U.S. Patents 2,618,608, 2,742,369, and 2,941,953 and summarized in U.S. Patent 4,101,441, all herein incorporated by reference.
Examples of suitable azoles and related heterocylic ring compounds include benzotriazole, tolyltriazole, alkyl or alkoxy substituted benzotriazoles wherein the substitution occurs on the 4 or 5 position of the benzene ring, 2-mercaptobenzothiazole, 2-mercaptobenzotriazole,1,2,3-triazole, 4-phenyl-1,2,3-triazole, 1,2-napthotriazole, 4-nitrobenzotriazole, pyrazole, 6-nitroindazole, 4-benzylpyrazole, 4,5-dimethylpyrazole, 3-allylpyrazole, imidazole, adenine, guanine, benzimidazole, 5-methyl benzimidazole, 2-phenyl imidazole, 2-benzyl imidazole, 4-allylimidazole, 4-(betahydroxy ethyl)-imidazole, purine, 4-methylimidazole, xanthine, hypoxanthine, 2-methyl imidazole, isoxazole, benzisoxazole, 3-mercaptobenzisoxazole, oxazole, 2-mercapto oxazole, 2-mercaptobenzoxazole, isothiazole, 3-mercaptoisothiazole, mercaptobenzisothiazole, benzisothiazole, thiazole, 2,5-dimercaptothiadiazole, 2,5-dimercaptobenzotriazole, 5,5'-methylene-bis-benzotriazole, and 4,5,6,7-tetrahydrobenzotriazole.
Additional suitable azoles include those disclosed in U.S. Patents 3,985,503, 4,298,568, 4,734,257, 4,744,950, 4,874,579, 5,217,686, and 5,236,626, all incorporated herein by reference, and 1-phenyl-5-mercaptotetrazole as disclosed in U.S. Patent 5,156,769, herein incorporated by reference. Suitable azoles include mixed compositions such as a tolyltriazole composition which includes at least 65% of the 5-methylbenzotriazole isomer by weight as disclosed in U.S. Patent 5,503,775, herein incorporated by reference. Particularly suitable are halogen-tolerant azoles which give improved corrosion performance, no objectionable odor, and reduced biocide consumption when halogen-based oxidizing biocides (e.g., chlorine) are used in the aqueous system. Non-limiting examples of such halogen-tolerant azoles are disclosed in U.S. Patents 5,772,919, 5,863,463 and 5,863,464, herein incorporated by reference, and include chloro-tolyltriazole, bromotolyltriazole, mono-halo-benzotriazole, di-halo-benzotriazole, and mixtures of mono-halo and di-halo-benzotriazoles.
Preferred azoles are tolyltriazole, benzotriazole and halogen-tolerant azoles, especially chloro-tolyltriazole.
Additional agents that may be combined with the tetrazolium compounds of this invention include aluminum corrosion inhibitors. Preferred are water soluble nitrate salts, particularly sodium nitrate, and the combination of nitrate salts with alkali metal silicates.
Additional agents that may be combined with the tetrazolium compounds of this invention include water-soluble metal salts of metals chosen from the group zinc, manganese, aluminum, tin, nickel, yttrium, and the rare earth metals (atomic numbers 57 to 71) and/or organic metal chelates of such metals, where the organic chelant is chosen to impart a desired level of water solubility of the metal ion. As is known in the art, such metal salts and chelates may be utilized to provide additional corrosion protection.
The use of zinc ions as a corrosion inhibitor is well known in the art, especially in combination with other water treatment agents such as phosphates, phosphonates, P-carboxylates, carboxylates and hydroxycarboxylates. Preferred sources of zinc ions are the sulfate, chloride, acetate, or nitrate zinc salts and the zincate ion obtained by dissolving zinc oxide in base.
Particularly preferred are the sulfate and chloride salts and the zincate ion.
The use of manganese ion in water treatment in combination with aminophosphonates and with P-carboxylates has been disclosed in U.S. Patent 4,640,818 and in European Patent 283191A2, respectively, both herein incorporated by reference. The use of yttrium and cations of the metals of the lanthanum series having atomic numbers from 57 to 71 and/or organics chelates thereof for corrosion inhibition in aqueous systems has been disclosed in U.S. Patents 4,749,550 and 5,130,052, both herein incorporated by reference. The preferred lanthanum salts are those of lanthanum, praseodymium, and neodymium, and commercially available materials which contain mixtures thereof.
Additional agents that may be combined with the tetrazolium compounds of this invention include scale and deposit control agents. Although many of the previously described combinations of this invention provide both corrosion and scale and/or deposit control (particularly for calcium carbonate scales), there may instances where additional agents must be utilized to control scaling and/or deposition for particular species (e.g., barium sulfate or calcium oxalate). Agents appropriate for control of a variety of such species are known in the art.
Additional agents that may be combined with the tetrazolium compounds of this invention include sequestering agents. Such agents are needed to prevent metallic (e.g., iron, copper) or alkaline earth ions from fouling the aqueous system or from interfering with the proper functioning of corrosion inhibitors or other agents in the system. Such sequestering agents are known in the art and in some cases may be selected to be effective on a specific ion. Non-limiting examples of suitable sequestering agents include ethylenediaminetetra(acetic acid) nitrolotriacetic acid, and N,N-di(2-hydroxyethyl)glycine or water soluble salts thereof.
Additional agents that may be combined with the tetrazolium compounds of this invention include anti-foams. Examples of suitable anti-foaming agents include silicones (e.g., polydimethylsiloxanes), distearylsebacamides, distearyladipamide and related products derived from ethylene oxide or propylene oxide condensations, and fatty alcohols, such as capryl alcohols and their ethylene oxide condensates.
Additional agents that may be combined with the tetrazolium compounds of this invention include biocides. The use of biocides may be necessary to control microbiological growth in both the aqueous system and in the feed sources for the compositions of this invention. Both oxidizing and non-oxidizing biocidal agents may be utilized for these purposes. Suitable oxidizing biocides include at least one of chorine, hypochlorite, bromine, hypobromite, chlorine and/or bromine donor compounds (e.g., bromochlorohydantoin), peracetic acid, inorganic peroxides and peroxide generators, chlorine dioxide, and ozone. Suitable non-oxidizing biocides include at least one of amines, quaternary ammonium compounds (e.g., N-alkyl dimethylbenzylammonium chloride), 2-bromo-2-nitropropane-1,3-diol, (3-bromonitrostyrene, dodecylguanidine hydrochloride, 2,2-dibromo-3-nitrilopropionamide, gluteraldhyde, chlorophenols, sulphur-containing compounds such as sulphones, methylene bis thiocyanates and carbamates, isothiazolones, brominated propionamides, triazines (e.g. terbuthylazine, and triazine derivatives such as those disclosed in U.S. patent 5,534,624 herein incorporated by reference), phosphonium compounds, organometallic compounds such as tributyl tin oxide, and mixtures of such biocides. A preferred non-oxidizing biocide is a mixture of (a) 2-bromo-2-nitropropane-1,3-diol (BNPD) and (b) a mixture of about 75% 5-chloro-2-methyl-4-isothiazolin-3-one and about 25% 2-methyl-4-isothiazolin-3-one, the weight ratio said BNPD (a) to said mixture (b) being about 16:1 to about 1:1 as disclosed in U.S. Patent 4,732,905, herein incorporated by reference.
Additional agents that may be combined with the tetrazolium compounds of this invention include freezing point depressants. Such agents are needed for aqueous systems such as refrigeration, dehumidification, and internal combustion engine coolant systems. The depressants may be ionic or non-ionic in nature. Non-limiting examples of suitable ionic agents include calcium chloride, sodium chloride, lithium bromide, and lithium chloride.
Examples of suitable non-ionic agents are water-soluble alcohols such as ethylene glycol, propylene glycol, ethanol, glycerol, isopropanol, methanol, and mixtures thereof.
Additional agents that may be combined with the tetrazolium compounds of this invention include pH adjusting agents. Non-limiting examples of suitable agents include sodium hydroxide, potassium hydroxide, lithium hydroxide, hydrochloric acid, sulfuric acid, nitric acid, carbon dioxide, ammonia, organic acids such as oxalic acid, alkali metal carbonates, and alkali metal bicarbonates.
When the compositions of this invention are used in aqueous systems that involve moving contact between a surface and a metal (e.g., such as encountered in systems containing pumping equipment or in applications involving metal machining or forming), it may be desirable to employ a lubricant to improve the performance of the machining operation or to decrease wear of the contacting and/or metal surface. Such lubricants may be water soluble or water insoluble.
Suitable water insoluble organic lubricants such as naturally occurnng or synthetic oils include those disclosed in U.S. 5,716,917, herein incorporated by reference. Suitable water soluble lubricants include those disclosed in U.S. patents 3,720,695, 4,053,426, 4,289,636, 4,402,839, 4,425,248, 4,636,321, 4,758,359, 4,895,668, 5,401,428, 5,547,595, 5,616,544, and 5,653,695, herein incorporated by reference. Some lubricants (e.g., those disclosed in U.S. patents 4,405,426 and 5,401,428, all herein incorporated by reference) may additionally impart improved corrosion inhibition performance to the compositions of this invention.
It may be advantageous either in the formulation of stable product containing a mixture of the components of this invention or in the application of the compositions of this invention to a particular aqueous system (particularly those systems in which significant proportions of nonaqueous fluids are present) to additionally employ surfactants. Such surfactants may be anionic, cationic, amphoteric or non-ionic in nature and are well known in the art. Such agents may be added to the compositions of this invention for a variety of functions (e.g., as emulsifiers, dispersants, hydrotroping agents, anti-foaming agents, lubricants, corrosion inhibitors). The process of selecting appropriate surfactants for accomplishing a given purpose is well known to those skilled in the art. It is particularly desirable to utilize surface active agents when utilizing additives to the compositions of this invention which have limited solubility in water (e.g., when employing water insoluble organic lubricants or supplementary corrosion inhibitors based on marginally soluble materials such as fatty acid derivatives).
Additional agents that may be combined with the tetrazolium compounds of this invention include calcium hardness adjusting agents. It is well known in the art that the efficacy of many aqueous system corrosion inhibitors, particularly those commonly used to treat open recirculating cooling system, is dependent upon the presence of a certain minimum level of dissolved calcium in the water. Although the efficacy of the compositions of this invention is somewhat independent of dissolved calcium, it may be advantageous in the practice of this invention to increase the dissolved calcium concentration in the system. Non-limiting examples of suitable calcium hardness adjusting agents include the bicarbonate, carbonate, chloride, sulfate, and acetate salts of calcium as well as calcium hydroxide and calcium oxide.
Additional agents that may be combined with the tetrazolium compounds of this invention include coloring agents. Non-limiting examples of the use of such agents include improving product appearance, aiding in product identification, and serving as additives on which automatic feed control systems which utilize colorimetric methods can be controlled. Non-limiting examples of such agents include water soluble dyes.
Surprisingly, it has been found that the tetrazolium compounds combine synergistically with a wide range of known scale and/or corrosion inhibitors to provide greatly increased performance for both generalized corrosion and pitting. The combinations are effective over a range of calcium hardness and pH, including low hardness waters. In some cases, a reduction of one order of magnitude or more in the corrosion rate occurs when employing the combination compared to the treatment without using a tetrazolium compound, even when keeping total active treatment levels constant.

The tetrazolium compounds of this invention are known to be reducible species.
While the mechanistic details have not been studied in depth and are not fully understood, it is believed that one important element of the corrosion inhibiting effect of the novel compositions of this invention is the reduction of the soluble tetrazolium compound to a relatively insoluble and S protective film at the surface of the corroding metal. The reduction may be a mufti-step process, and the protective film may contain several of the intermediate reduction products. Potentially, some of these intermediate reduction products may not be part of the protective film, but may be still capable of further reduction to form a corrosion-inhibiting film. Such corrosion-inhibiting intermediate reduction products of the tetrazolium compounds are also considered to be within the scope of this invention.
The protective action of the tetrazolium compound works in concert with the protective action of the additional water treatment agent to provide effective aqueous system corrosion control. In many cases the additional water treatment agent also provides protection against water formed scales and deposits, and for these cases, the combinations of this invention are effective for the control of both corrosion and scaling/deposition. The additional water treatment agent may impart other desirable properties to the composition (e.g., the ability to disperse particulate matter). However, it is possible for certain water treatment agents (e.g., oxygen scavengers) to cause the reduction of the tetrazolium compound directly in solution, making the tetrazolium compound itself or potential corrosion-inhibiting intermediate reduction products unavailable to form a protective film at the metal surface. Consequently, water treatment agents that substantially reduce tetrazolium compounds in aqueous solution under the particular conditions of use are not suitable for use with this invention. The conditions of use include such considerations as the relative proportions of tetrazolium compound and the tetrazolium-reducing water treatment agent (e.g., the use of an amount of a reducing water treatment agent that did not substantially reduce the amount of tetrazolium compound present would still fall within the scope of this invention). The conditions of use also would include the absolute concentrations of both tetrazolium compounds and other species, temperature, time, the presence or absence of additional oxidizing and/or reducing agents or other compounds that might alter the interaction between the tetrazolium compound and the tetrazolium-reducing water treatment agent, the presence or absence of catalytic surfaces (e.g., metal surfaces), and the like. One skilled in the art may readily determine if a particular agent substantially reduces the tetrazolium compound under the conditions of use. Because the reduction products of the tetrazolium compounds are generally highly colored while the parent materials are not, simple methods of making this determination include visual inspection and colorimetry.
Expanding upon the above, the aqueous system does not contain materials therein that affect the corrosion inhibition of the tetrazolium compounds so that the tetrazolium compound S does not inhibit corrosion. Therefore, the tetrazolium compounds should not be substantially reduced by the materials so that the tetrazolium compound cannot inhibit corrosion. Moreover, any materials that negate the corrosion inhibition and/or scaling prevention of the terazolium compounds and/or additional materials should preferably not be included in the aqueous system, or should preferably be included in amounts that would not permit the tetrazolium compounds from achieving their intended corrosion inhibition and/or scaling prevention.
In a preferred embodiment of the present invention, from about 0.5 to 10,000 parts per million of a combination of a tetrazolium compound and an aqueous system treatment material is added to the aqueous system in need of treatment, with from about 10 to 1000 parts per million of said combination being particularly preferred. The weight ratio of the other aqueous system treatment material to tetrazolium compound is preferably from about 100:1 to 1:20, with a weight ratio of from about 20:1 to 1:1 particularly preferred.
The pH of the aqueous system in which the compositions of this invention may be applied ranges from about 5 to about 12. The pH is preferably in the range from about 6 to about 10.
The components of this invention may be dosed into the aqueous system at an effective concentration by a slug feed or by blending with the aqueous fluid as the system is being filled.
When used to treat aqueous systems in which one or more of the treatment components are discharged from the system or are consumed by chemical or physical processes within the system and thus require replenishment to maintain treatment effectiveness (e.g., open cooling systems), the compositions of this invention may be fed to the system on a continuous basis, on an intermittent basis, or using a combination of the two (e.g., utilizing a continuous low level feed supplemented by slug feeds as needed). Depending upon the application, it may be advantageous to combine the compositions of this invention together into a single treatment fed from one feed supply source, or, alternatively, to separate the components into two or more treatment sources, each source independently being fed continuously or intermittently into the system at a rate needed to maintain adequate concentrations in the system. Single or multiple feed points to the aqueous system for each treatment source may be utilized.

The timing and rate of treatment feed may be controlled by a variety of methods known in the art. One suitable method is to utilize metering pumps or other feed system devices which may be variously configured to feed continuously at a fixed rate, on a time schedule, on signals generated by other system components such as makeup or blowdown pumps, or on signals generated by an analog or computer-based feed control system. Non-limiting examples of suitable feed systems have been disclosed in U.S. Patents 4,648,043, 4,659,459, 4,897,797, 5,056,036, 5,092,739 and 5,695,092. The feed control systems may utilize signals corresponding to the concentration of one or more of the treatment components, to the concentration of one or more inert or active tracer materials added to the treatment, to the value of one or more measures of system performance (e.g., values obtained from corrosion rate meters, scaling monitors, heat transfer monitoring devices, analytical devices that detect the amount corrosion product in the water such as total or dissolved iron or other metal constituent, and the like), to the value of one or more of the physical characteristics of the system (e.g., temperature, flow rate, conductivity), to the value of one or more chemical characteristics of the system (e.g., pH, calcium hardness, redox potential, alkalinity) or to combinations of these signals to feed and maintain levels of treatment adequate for effective performance in a particular aqueous system.
Alternatively, it may be advantageous in some systems to employ a controlled release (also referred to as gradual release or time release) delivery system for some or all the compounds of this invention. In such controlled release systems the material or materials to be fed are impregnated or are otherwise incorporated into a controlled release system matrix. Suitable controlled release delivery systems include those in which the matrix is exposed to the fluid in the aqueous system or to a fluid stream being fed to the aqueous system and the treatment components are gradually released into the system by the action of various processes (e.g., diffusion, dissolution, osmotic pressure differences) and which may further be designed to vary the release rate in response to aqueous fluid characteristics such as temperature, flow rate, pH, water hardness, conductivity, and the like.
Non-limiting examples of such controlled release delivery systems have been disclosed in U.S.
Patents 3,985,298, 4,220,153, 5,316,774, 5,364,627, and 5,391,369.
When feed systems are employed that utilize measured concentrations of treatment or tracer components, such concentrations may be determined by continuous, semi-continuous, or batch type analytical techniques including spectroscopic methods (UV, visible emission, visible absorption, IR, Raman, fluorescence, phosphorescence, etc.), electrochemical methods (including pH, ORP, and ion selective electrode measurements), chromatographic methods (GC, LC), methods that rely on antibody binding or release, chemical based analytical/colorimetric methods such as those commercially available from the Hach Company, and the like. A
suitable spectrophotometric method is described in U.S. 5,242,602, herein incorporated by reference. A
suitable method for regulating the in-system concentration of a water treatment agent is disclosed in U.S. 5,411,889. U.5. 5,855,791, herein incorporated by reference, discloses suitable methods for determining the feed rates of corrosion and fouling inhibitors based on certain performance monitors and system characteristics.
The tracer compounds that may optionally be employed may be compounds that serve no particular treatment function, referred to as inert tracers, or may be water treatment compounds that are also readily monitored, such treatment compounds being referred to as active tracers.
Suitable tracers include soluble lithium salts such as lithium chloride, transition metals such as described in U.S. 4,966,711, herein incorporated by reference, and fluorescent inert tracers such as described in U.S. 4,783,314, herein incorporated by reference. Suitable fluorescent inert tracers include the mono-, di-, and trisulfonated naphthalenes (e.g., water soluble salts of naphthalene sulfonic acid or of naphthalene disulfonic acid). Suitable active tracers include fluorescently tagged polymers such as described in U.S. 5,171,450, herein incorporated by reference, and polymers containing a photo-inert, latently detectable moiety which will absorb light when contacted with a photoactivator, as described in U.S. 5,654,198, herein incorporated by reference, azole-based copper corrosion inhibitors such as tolyltriazole, and water soluble molybdate and tungstate salts.
Although many of the compounds combined with the tetrazolium compounds are known corrosion inhibitors, they are generally known to be effective only under particular conditions of calcium hardness and pH. For example, certain phosphonocarboxylates such as 2-phosphono-butane-1,2,4-tricarboxylic acid (PBTC) are generally effective as corrosion inhibitors only at pHs exceeding 8 and in waters containing significant calcium hardness (i.e., > 200 mg/1 as CaC03).
As will be demonstrated, combinations of PBTC with the tetrazolium compounds are very effective at pH 7.6 in a water containing only 100 mg/1 calcium as CaC03.
Similar results are seen with other combinations. It is particularly advantageous in many aqueous systems to have treatments that are "robust" with respect to the pH and hardness of the water, i.e., that perform well over a wide range of these conditions.
Use of the tetrazolium compound can significantly reduce the total treatment dosage needed to effectively limit corrosion in the aqueous system. Many of the combinations of the tetrazolium compounds are with materials that are primarily or exclusively utilized as scale and/or deposition inhibitors. However, the combinations are effective for both scaling/deposition and corrosion control.
Test Methods and Conditions The corrosion inhibition activity of the treatments in the present invention were evaluated using the Beaker Corrosion Test Apparatus (BCTA). The BCTA consists of a 2 liter beaker equipped with an air/C02 sparge, 1010 low carbon steel (LCS) coupon(s), a 1010 LCS
electrochemical probe, and a magnetic stir bar. The test solution volume was 1.9 liters. Air/COz sparging is continuous during the test. The reference electrode and counter electrode used in making the electrochemical corrosion measurements are constructed of Hastelloy C22. The beaker is immersed in a water bath for temperature control. Electrochemical corrosion data were obtained periodically on the probe during the test using a polarization resistance technique. All tests were conducted at 120°F, using a 400 RPM stir rate. Unless otherwise noted, the test duration was 18 hours. Two values are reported for each test; EC(avg), the average value of the electrochemically measured corrosion rate during the test, and EC(18 hour), the value of the corrosion rate at the end of the test. The latter value is thought to be more indicative of the longer term corrosion rate expected.
In all tests the coupons) immersed in the beaker during the test is photographed. For some tests, the pit depths on the coupons are measured using a microscopic technique (see ASTM G 46-94, section 5.2.4). For these pit measurement tests, two coupons are used and up to 20 pits per coupon are measured (up to 10 per side).
Unless specifically noted otherwise, the test water contains 100 mg/1 Ca (as CaC03), 50 mg/1 Mg (as CaC03), 100 mg/1 chloride, and 100 mg/1 sulfate. Using this water, tests were conducted at pHs of 8.6, 7.6, and 6.8. The corresponding "M" alkalinities at these pHs were 110, 32, and 4 mg/1 (all as CaC03).
It is relatively difficult to control ferrous metal corrosion in this test water. The relatively low calcium hardness makes is difficult for inhibitors which depend on calcium to function effectively. The relatively high sulfate and chloride levels (for the given calcium level) makes the water aggressive to ferrous metals, particularly with respect to pitting corrosion.
To prevent calcium carbonate and/or calcium phosphate deposition from occurring during the test, many of the tests were conducted using 5 mg/1 of a Polyepoxysuccinic Acid (PESA) with a degree of polymerization of about 5 and 5 mg/1 active of a copolymer of acrylic acid and allylhydroxypropylsulfonate ether sodium salt (AA/AHPSE) added to the test water. For some tests, only 5 mg/1 of AA/AHPSE copolymer was used.
Both addition and substitution (constant inhibitor level) tests were conducted. In former type of test, a low level of a tetrazolium compound (2 to 5 mg/1) was added to a second composition. In the latter test, the second composition was reduced by a given amount (3 to 5 mg/1) and replaced by the same amount of tetrazolium compound.
Performance Examples Example #1 BCTA results for tests conducted at pH 8.6 are shown in Table 1. The tetrazolium compound utilized for these tests was NBT. Belcor 575 is hydroxyphosphonoacetic sold by FMC.
Bricorr 288 is a mixture of phosphonosuccinic acid, the phosphonated dimer of malefic acid, phosphoric acid, and a minor proportion by weight of higher phosphonated oligomers of malefic acid sold by Albright and Wilson. bequest 2060 is diethylenetriamine penta(methylenephosphonic acid) sold by Monsanto. Bayhibit AM is 2-phosphonobutane-1,2,4-tricarboxylic acid sold by Bayer. Goodrite K-752 is a polyacrylate sold by B.
F. Goodrich.
As can be seen from Table 1, in all cases except for Bricorr 288, the addition or substitution of low levels of NBT synergistically improves corrosion performance. Such factors as, e.g., particular test conditions may have contributed to the Bricorr 288 result in this case.

Table 1 pH 8.6 With 5 mg/1 active PESA & 5 mg/I active AA/AHPSE
mg/1 INHIBITOR mg/1 EC EC
(all as actives)NBT av 18 0 ---- 5 7.7 5.5 20 L-Tartaric 0 6.2 8.5 Acid 20 L-Tartaric 2 2.6 3.2 Acid 20 L-Tartaric 5 2.7 2.7 Acid 15 HEDP 0 2.5 2.0 10 HEDP 0 3.0 2.1 7 HEDP 3 2.2 2.2 1 S 15 Belcor 575 0 3.8 2.8 10 Belcor 575 0 5.6 4.6 7 Belcor 575 3 1.7 1.2 15 Bricorr 288 0 3.8 2.9 10 Bricorr 288 0 4.7 4.0 7 Bricorr 288 3 6.2 4.4 15 Goodrite 0 25 53 12 Goodrite 3 8.8 17 15 De uest 20600 4.0 3.2 10 De uest 20600 7.3 8.8 7 De uest 20603 3.6 2.7 15 Ba hibit 0 6.1 5.7 AM

10 Ba hibit 0 8.1 9.1 AM

Example #2 Corrosion results for tests conducted at pH 7.6 with both AA/AHPSE and PESA
present are shown in Table 2. Results with AA/AHPSE only are shown in Table 3. In these waters, an EC(18) of 3 mpy or less is considered to be an acceptable corrosion rate for most industrial applications. In some cases shown in Table 3, the corrosion rates with the tetrazolium compound present are not acceptable. However, the synergistic improvement of the combination of first component with the tetrazolium compound is obvious, and one skilled in the art may readily determine both the effective total amount of inhibitor needed as well as the relative proportions of the tetrazolium compound and other component that are needed to obtain the corrosion protection needed for the application of interest.
The trends noted above for results at pH 8.6 are also seen at pH 7.6. Results for tests with Bricorr 288 are shown in graphical form in Figure 1 to more clearly illustrate the synergistic improvement obtained by utilizing the tetrazolium compound NBT in combination with this material.
Example #3 Corrosion results for tests conducted at pH 6.8 are shown in Table 2 H 7.6 with 5 mg/1 active PESActive AHPSE
and 5 mg/1 a AA/

mg/ INHIBITOR mg/1 EC EC
(all as actives) NBT av 18 0 -___ 0 67 87 0 _-__ 2 65 73 0 _-_- 5 28 32 0 __-- 5 40 36 10 Goodrite K-752 0 19 37 10 Goodrite K-752 2 27 38 10 Goodrite K-752 5 11 12 20 Goodrite K-752 0 11 11 20 Goodrite K-752 2 7.4 6.9 20 Goodrite K-752 5 1.3 0.7 20 Goodrite K-732 0 14 23 25 Goodrite K-732 0 7.4 8.0 20 Goodrite K-732 2 6.4 5.6 20 Goodrite K-732 5 0.9 0.4 20 50:50 mix of Goodrite K-7520 12 18 and K-732 20 50:50 mix of Goodrite K-7522 7.8 8.8 and K-732 20 50:50 mix of Goodrite K-7525 1.3 0.6 and K-732 20 A 5 1.8 1.1 25 B 0 9.4 7.7 20 B 5 2.0 1.0 20 C 5 1.1 0.5 5 ortho-P04 0 4.1 3.0 5 ortho-P04 2 0.9 0.3 5 ortho-P04 5 0.8 0.4 20 Bricorr 288 0 5.3 4.6 15 Bricorr 288 5 1.1 0.4 20 Bayhibit AM 0 12 8.7 15 Ba hibit AM 5 2.0 0.5 A: N, N'-bis (2-hydroxysuccinyl)-6,6-hexanediamine, as Na salt B: iminodi(2-hydroxysuccinic acid), as Na salt C: N,N'-bis (2-hydroxy succinyl)-m-xylenediamine, as Na salt Table 3 pH 7.6 with 5 mg/1 activeA/AHPSE
A

mg/1 INHIBITOR mg/1 EC EC
(all as actives) NBT avg 18 20 Bricorr 288 0 5.6 5.5 17 Bricorr 288 3 1.8 0.4 15 Bricorr 288 5 1.6 0.4 10 Bricorr 288 10 0.7 0.2 5 Bricorr 288 15 5.8 3.2 10 Bricorr 288 5 1.9 0.7 5 Bricorr 288 5 20 16 20 PESA 5 1.8 0.8 30 PESA 5 1.0 1.0 25 Citric acid 0 14 13 30 Citric Acid 0 12 14 10 Citric Acid 5 21 16 20 Citric Acid 5 2.3 0.9 30 Citric Acid 5 1.3 0.4 30 Goodrite K-732 0 6.1 6 10 Goodrite K-732 5 9.7 10 20 Goodrite K-732 5 0.8 0.5 30 Goodrite K-732 5 0.7 0.3 25 Belclene 200 0 14 13 30 Belclene 200 0 14 12 10 Belclene 200 5 6.8 6.3 20 Belclene 200 5 1.3 0.7 30 Belclene 200 5 1.2 0.7 25 2,3-Dihydroxybenzoic 0 7.7 7.0 acid 20 2,3-Dihydroxybenzoic 5 0.97 0.49 acid 25 1,2,3,4-Butanetetracarboxylic0 12 23 acid 20 1,2,3,4-Butanetetracarboxylic5 9.3 7.5 acid 75 Sodium tetraborate (Borax)0 64 77 70 Sodium tetraborate (Borax)5 58 51 30 Nitrite (from sodium 0 59 62 nitrite) 25 Nitrite (from sodium 5 36 45 nitrite) 60 Nitrite (from sodium 0 25 41 nitrite) 55 Nitrite (from sodium 5 11 14 nitrite) Table 3 - Continued uH 7.6 with 5 mg/I active AA/AHPSE
mg/1 INHIBITOR mg/1 EC EC
(all as actives) NBT av 18 25 Mesotartaric acid 0 9.4 7.7 20 Mesotartaric acid 5 1.7 0.93 30 Gluconic acid 5 3.6 2.2 20 N-Lauroyl sarcosine 0 46 73 15 N-Lauroyl sarcosine 5 30 30 25 1,10-Phenanthroline 0 59 66 20 1,10-Phenanthroline 5 40 28 30 Belsperse 161 (oligomeric0 5.2 4.4 PAA with hos hino rou s 25 Belsperse 161 (oligomeric5 1.1 0.31 PAA with hos hino rou s) 30 Low mol.wt.polyacrylic 0 6.6 7.1 acid (PAA) with phosphonic acid end group, Na salt 25 Low mol.wt. PAA with 5 1.7 0.84 phosphonic acid end rou , Na salt 30 Belclene 500 (Oligomeric0 14 17 PAA with hos hino rou ) 25 Belclene 500 (Oligomeric5 2.5 0.93 PAA with hos hino rou 30 Belclene 400 (AA:AMPS 0 11 10 with hos hinate) 25 Belclene 400 (AA:AMPS 5 3.3 1.2 with hos hinate) 30 Belclene 494 (AA:AMPS 0 8.3 7.7 with hos honate end) 25 Belclene 494 (AA:AMPS 5 7.2 7.2 with hos honate end Polycrylates 25 Goodrite K-732 5 1.1 0.35 20 Goodrite K-752 5 1.5 0.65 30 Goodrite K-752 5 0.96 0.43 Modified Polyexpoxysuccinic acid 25 m-Xylylenediamine/PESA 5 0.98 0.48 derivative #
1, as Na salt 25 m-Xylylenediamine/PESA 5 1.7 0.62 derivative #
2, as Na salt 25 m-Xylylenediamine/PESA 5 1.7 0.72 derivative #
3, as Na salt 25 m-Xylylenediamine/PESA 5 1.8 0.73 derivative #
4, as Na salt Table pH
6.8 With mg/1 active PESA
and m active AA/AHPSE

mg/1 INHIBITOR mg/1 EC EC
(all as actives)NBT avg 18 20 A 5 3.7 1.5 20 B 5 2.0 0.6 20 5 2.7 2.3 25 Ketomalonic acid0 6.2 5.3 20 Ketomalonic acid5 2.3 1.9 25 L-tartaric acid 0 17 17 20 L-tartaric acid 5 4.3 2.0 25 Saccharic acid 0 13 12 20 Saccharic acid 5 2.2 0.9 7 ortho-PO 0 4.5 4.1 7 ortho-P 2 1.4 1.0 7 ortho-P04 5 1.0 0.6 20 Bricorr 288 0 5.0 6.2 15 Bricorr 288 5 1.3 0.5 20 HEDP 0 7.3 5.9 15 HEDP 5 1.0 0.6 20 Belcor 575 0 5.7 8.5 15 Belcor 575 5 0.7 0.6 20 molybdate, as 0 15 33 Mo0 15 molybdate, as 5 11 12 Mo0 30 molybdate, as 0 8.1 11 Mo0 25 molybdate, as 5 2.8 3.1 Mo0 25 oodrite K-732 0 8.8 8.4 EFFICACY AT INHIBITING GROWTH OF PITS
Example #4 Pit depth results for varying exposure times for tests at pH 8.6 with tartaric acid are shown in Table 5. As the results show, addition of NBT is very effective at limiting the growth of pits.
S Pitting is a particular problem for non-phosphorus inhibitors such as tartaric acid.
Table 5 Pit Depths as a Function of Immersion Time 20 mg/1 Tartaric Acid, pH 8.6 Test With 5 mg/1 active PESA and 5 mg/1 active AA/AHPSE
Pit depths in microns; tabulated values are averages ADDITIVE

Immersion None 2 mg/1 5 mg/1 (hours) NBT NBT

Example #5 Pit depth and pit count data for tests at pH 7.6 with ortho-phosphate are shown in Table 6. These results show that NBT is effective both at reducing pit depths and pit densities.
Table 6 Pit Depth and Count 7 mg/1 ortho-P04, pH 7.6, 18 hour test With 5 mg/1 active PESA and 5 mg/1 active AA/AHPSE
Pit depths in microns; tabulated values are averages ADDITIVE

None 2 mg/1 5 mg/1 NBT NBT

De th 22 11 9 Pit Count80* 39 18 * More pits existed but total pit count was not obtained Example #6 Shown in Table 7 are pitting data obtained at 10 mg/1 total added inhibitor which further demonstrate the pit growth inhibiting property of NBT. Although pit densities were higher in the treatments containing NBT, pit depths were significantly lower. The significant impact of NBT
on general corrosion rate can clearly be seen in the case of Bayhibit AM.
Table 7 pH 8.6 Results with 5 mg/1 Copolymer of acrylic acid/1-allyloxy-2-hydroxypropane sulfonic acid and 5 mg/1 PESA present PD = Pit depth measured on coupons at end of test, in microns Max = maximum depth, Avg = average depth, Min = minimum depth mg/1 Inhibitor mg/1 EC EC Total Max Avg Min (as actives)NBT (avg) (18) # its PD PD PD

HEDP 0 3.0 2.1 8 48 42 40 7 HEDP 3 2.2 2.2 20 23 14 8 10 Bayhibit 0 8.1 9.1 11 82 58 38 AM

7 Bayhibit 3 3.4 3.0 20 68 30 7 AM

Additional Examples - Other Test Waters The hardness and pH of waters in aqueous systems such as cooling towers and the like can vary widely. It is greatly advantageous to have inhibitor formulations which can function effectively over a wide hardness range and pH range while inhibiting both corrosion and deposition. It is of further advantage in certain systems that must use uncycled water which typically has low calcium (< 100 mg/1 Ca as CaC03) and is relatively neutral pH (6.5-7.5) that the inhibitors used need not rely on alkaline pH, high hardness conditions to function effectively, as is the case with many of the treatments currently in use. Examples of such systems are closed loop cooling systems once through cooling systems, hot water heating systems, and the like. The following examples further establish the wide-ranging effectiveness of inhibitor formulations containing a tetrazolium compound and the improvement obtained over materials known in the art when a tetrazolium compound is utilized in conjunction with other components described in this disclosure.
Example #7 Low pH, low hardness Table 8 shows results from a water containing 15 mg/1 Ca as CaC03, 7.6 mg/1 Mg as CaC03, 71 mg/1 Cl, 48 mg/1504, with S mg/1 active AA/AHPSE at pH 7Ø A
significant decrease in corrosion rate is observed when 5 mg/1 NBT is added.

Table 8 mg/1 Treatment mg/1EC EC
NBT avg (18) 10 O-PO 0 12 9.7 10 O-PO 5 1.2 0.67 20 Bricorr 288 0 10 9.2 20 Bricorr 288 5 0.96 0.21 20 HEDP 0 9.1 9.0 20 HEDP 5 0.89 0.13 20 Belcor 575 0 5.9 5.8 20 Belcor 575 5 0.51 0.21 30 Goodrite 0 6.1 6.4 30 Goodrite 5 0.48 0.12 60 L-Tartaric 0 13 12 acid 60 L-Tartaric 5 2.4 1.2 acid 20 Ketomalonic 0 5.3 6.3 20 Ketomalonic S 1.1 0.70 20 Saccharic 5 2.1 1.1 Acid O - P04: orthophosphate HEDP: Hydroxyethylidene diphosphonic acid Example #8 Lower pH, higher hardness Results of BCTA tests conducted at pH 6.8 in a water containing 500 mg/1 Ca as CaC03, 250 mg/1 Mg as CaC03, 7 mg/1 MAIk as CaC03, 354 mg/1 chloride, and 500 mg/1 sulfate are shown in Table 9. All tests contained 5 mg/1 active AA/AHPSE. Conditions of this kind are often encountered in open recirculating cooling systems where the source (makeup) water has been concentrated several times due to evaporation and sulfuric acid has been added to maintain relatively low pH. In these series of tests the total inhibitor concentration was kept constant or nearly constant for each pair of comparisons (with and without NBT). In each case, replacement of part of the inhibitor or inhibitor blend with NBT resulted in a significant improvement in corrosion performance. As previously noted, not all combinations with the tetrazolium compound provide acceptable corrosion performance, but the combination in all cases improves performance.
One skilled in the art may readily determine the appropriate levels and ratios needed to obtain satisfactory performance in a particular aqueous system.

Table 9 mg/I Treat mg/1 Treat mg/I EC EC
#1 #2 NBT (av (18 10 O-P04 0 7.5 5.0 5 O-P 4 5 2.3 1.6 7 -P 4 3.0 P o-P 0 2.9 1.2 5.5 O-P04 2.5 P o-PO 3 0.99 0.37 2.0 P o-P 3 1.6 0.77 15 Bricorr ------16 Bricorr 0 2.6 1.6 12 Bricorr 5 1.5 0.92 25 Saccharic--- --- 0 34 60 20 Saccharic--- --- 5 13 11 15 Saccharic4 O-PO 0 7.9 8.2 12 Saccharic3 O-PO 5 2.1 1.3 16 D 4 O-PO 0 12 7.7 T7 ~ O-P(y 5 ~ 1 _9 O_R9 ~

D: imino-di(2-hydroxy succinic acid), as Na salt Example #9 Higher pH, moderate hardness water Table 10 shows the results from a pH 8.6 test water that contains 360 mg/1 Ca as CaC03, 180 mg/1 Mg as CaC03, 255 mg/1 Cl, 220 mg/1 S04, and 300 mg/1 Malk as CaC03.
All tests contain 5 mg/1 active AA/AHPSE. Conditions of this kind are often encountered in open recirculating cooling systems where the source (makeup) water has been concentrated several times due to evaporation and the pH has been controlled to be in the mid-pH 8 range to make it easier to control ferrous corrosion. The effectiveness of the addition of a tetrazolium compound under these conditions is apparent from these results.

Table 10 mg/1 Treat mg/1 Treat mg/1 EC EC
#1 #2 NBT (av (18 ) 5 PESA --- --- 5 6.7 3.3 20 PESA --- --- 0 7.6 7.0 10 PESA --- --- 5 4.5 2.7 20 PESA --- --- 5 2.5 1.7 10 PESA 10 L-Tartaric0 7.3 4.3 acid 10 PESA 10 L-Tartaric5 2.5 1.9 acid 10 AcumerTM --- --- 0 11 7.8 10 AcumerTM --- --- 5 3.7 1.6 20 Acumer 4210--- --- 0 6.4 4.1 20 Acumer 4210--- --- 5 2.2 2.0 10 Acumer 421010 PESA 0 6.4 4.3 10 Acumer 421010 PESA 5 2.6 2.0 10 Acumer 421010 L-Tartaric0 5.4 3.5 Acid 10 Acumer 421010 L-Tartaric5 1.9 1.6 Acid Acumer 4210: Polymaleic acid, available from Rohm & Haas Example #10 ADDITIONAL TETRAZOLIUM COMPOUNDS
Data obtained with NBT and three additional tetrazolium compounds: Distyryl Nitroblue Tetrazolium Chloride (DNBT), Tetranitro Blue Tetrazolium Chloride (TNBT), and 2-(4-lodophenyl)-3-(4-nitrophenyl)-5-phenyltetrazolium chloride (INT) at pH
7.6 are shown in Table 11. The test water is the same as for Example 2. Other than the DNBT
combination with Belclene 200, the synergistic interaction of the combination of a tetrazolium compound with other materials disclosed in this invention is evident.

INHIBITOR mg/1 Tetrazoliummg/1EC EC
(all as actives) com ound av 18 $ ---- ---- TNBT 25 12 9.0 ---- ---- INT 25 9.0 5.7 Bricorr 288 25 ---- ----4.4 4.2 Bricorr 288 20 DNBT 5 1.5 0.9 Bricorr 288 20 TNBT 5 1.1 0.8 Bricorr 288 20 INT 5 4.0 3.7 Bricorr 288 15 NBT 5 1.6 0.4 Belclene 25 ---- ----15 13 Belclene 20 DNBT 5 21 22 Belclene 20 TNBT 5 5.5 5.2 Belclene 20 INT 5 6.7 11 Belclene 20 NBT 5 1.3 0.7 While this invention has been described with respect to particular embodiments thereof, it is apparent that numerous other forms and modifications of this invention will be obvious to those skilled in the art. The appended claims and this invention generally should be construed to cover all such obvious forms and modifications which are within the true spirit and scope of the present invention.

Claims

We claim:

1. A composition for controlling the corrosion of metals in contact with an aqueous system having a pH of about 6 or greater which comprises a combination of:
(a) a tetrazolium compound of the formula:

wherein R1, R2 and R3 are selected from the group consisting of lower alkyl, branched lower alkyl, aryl, substituted aryl, alkylaryl, substituted alkylaryl and heterocyclic substituted aryl, with the proviso that neither R1, R2, or R3 contain more than 14 carbon atoms;
and n is 1 or 2, such tetrazolium compound optionally having associated water soluble ionic species if needed to obtain a neutral charge, and (b) at least one other aqueous system treatment material chosen so that the material does not substantially reduce the tetrazolium compound.
2. A composition as recited in claim 1 wherein said other aqueous system treatment material is selected from the group consisting of inorganic phosphates, borates, nitrites, compounds that release a metal anion in water, 2,3-dihydroxybenzoic acid, 1,10-phenanthroline, polycarboxylates, akyl hydroxycarboxylic acids, aminohydroxysuccinic acids, carboxyamines, polyepoxysuccinic acids, modified polyepoxysuccinic acids, monophosphonic acids, diphosphonic acids, phosphonocarboxylic acids, hydroxyphosphonocarboxylic acids, aminophosphonic acids, phosphonomethylamine oxides, polymeric amine oxides, polyetherpolyaminomethylene phosphonates, polyetherpolyamino-methylene phosphonate N-oxides, iminoakylenephosphonic acids, long chain fatty acid derivatives of sarcosine;
telomeric, co-telomeric, polymeric, or copolymeric phosphorus-containing carboxylates, alkali metal silicates, monofluorophosphate, amines, diamines, alkanolamines, ether amines, fatty amines and diamines, quaternized amines, oxyalkylated amines, akyl pyridines, tetrazoles, imidazoline and substituted imidazolines, amidoamines, polyamines, polyakylenepolyamines, alkyl derivatives of benzene sulfonic acid, benzoates and substituted benzoates, aminobenzoates, salicylates, dimer-trimer acids, petroleum oxidates, borogluconates; lignins, lignosulfonates, tannins; straight chain C5-C11 monocarboxylates and C4-C15 .alpha.,.omega.-dicarboxylates; amine salts of carboxylic acids and mercaptocarboxylic acids, amino acids, polyamino acids, hydroxyether acids and related lactone compounds, N-acyliminodiacetic acids; triazine di- and tri-carboxylic acis, phospho- and phosphate esters;
and monofluorophosphates; water soluble salts thereof, and mixtures thereof.
3. A composition as recited in claim 1 wherein said tetrazolium compound is selected from the group consisting of the water soluble salts of Nitro Blue Tetrazolium (2,2'-Di-p-nitrophenyl-5,5'-distyryl-3,3'-[3,3'-dimethoxy-4,4'-biphenylene]
ditetrazolium), Distyryl Nitroblue Tetrazolium (2,2'-Di-p-nitrophenyl-5,5'-distyryl-3,3'-[3,3'-dimethoxy-4,4'-biphenylene] ditetrazolium), Tetranitro Blue Tetrazolium (3,3'-(3,3'-Dimethoxy-4,4'-biphenylene)-bis-[2,5-p-nitrophenyl-2H-tetrazolium) and Iodonitro Tetrazolium (2-(4-lodophenyl)-3-(4-nitrophenyl)-5-phenyltetrazolium).
4. A composition as recited in claim 2 wherein said tetrazolium compound is selected from the group consisting of the water soluble salts of Nitro Blue Tetrazolium (2,2'-Di-p-nitrophenyl-5,5'-distyryl-3-,3'-[3,3'-dimethoxy-4,4'-biphenylene]
ditetrazolium), Distyryl Nitroblue Tetrazolium (2,2'-Di-p-nitrophenyl-5,5'-distyryl-3,3'-[3,3'-dimethoxy-4,4'-biphenylene] ditetrazolium), Tetranitro Blue Tetrazolium (3,3'-(3,3'-Dimethoxy-4,4'-biphenylene)-bis-[2,5-p-nitrophenyl-2H-tetrazolium) and Iodonitro Tetrazolium (2-(4-lodophenyl)-3-(4-nitrophenyl)-5-phenyltetrazolium).
5. A composition as recited in claim 1 wherein said water soluble ionic species are anions selected from the group consisting of halogens, nitrates, nitrites, carbonates, bicarbonates, sulfates, phosphates, and transition metal oxygenates.
6. A composition as recited in claim 5 wherein said halogens are selected from the group consisting of chlorides, fluorides, bromides and iodides.
7. A composition as recited in claim 6 wherein said halogen is chloride.
8. A composition as recited in claim 5 wherein said transition metal oxygenate is selected from the group consisting of molybdate, chromate, and tungstate.
9. A composition as recited in claim 8 wherein said transition metal oxygenate is molybdate.

10. A composition as recited in claim 2 wherein said inorganic phosphates are orthophosphates, polyphosphates, water soluble salts thereof and mixtures thereof.
11. A composition as recited in claim 2 wherein said inorganic phosphates are a mixture of orthophosphoric acid and pyrophosphoric acid or the water-soluble salts thereof.
12. A composition as recited in claim 2 wherein said borate is a water-soluble borate selected from the group consisting of tetraborates, metaborates, and orthoborates.
13. A composition as recited in claim 12 wherein said water-soluble borate is sodium tetraborate or a hydrate of sodium tetraborate.
14. A composition as recited in claim 2 wherein said nitrite is sodium nitrite.
15. A composition as recited in claim 2 wherein the metal anion releasing compounds are selected from the group consisting of the water soluble salts of molybdate, tungstate, vanadate, metavanadate, and chromate.
16. A composition as recited in claim 15 wherein the water soluble salt of a molybdate is sodium molybdate or a hydrate of sodium molybdate.
17. A composition as recited in claim 2 wherein said polycarboxylates comprise aliphatic compounds containing between about 4 and about 20 carbon atoms which are multiply substituted with carboxylate groups or water soluble salts thereof.
18. A composition as recited in claim 17 wherein said polycarboxylate is 1,2,3,4-butanetetracarboxylic acid.
19. A composition as recited in claim 2 wherein said polycarboxylate is a homopolymer obtained from the polymerization of an ethylenically unsaturated monomer containing one or more carboxyl groups.
20. A composition as recited in claim 19 wherein said homopolymer is polyacrylic acid or its water soluble salts.
21. A composition as recited in claim 19 wherein said homopolymer is polymaleic acid or its water soluble salts.
22. A composition as recited in claim 19 wherein said homopolymer is polymaleic anhydride or its water soluble salts.
23. A composition as recited in claim 2 wherein said polycarboxylate is a copolymer obtained from the polymerization of two or more different ethylenically unsaturated monomers, each of said monomers containing one or more carboxyl groups.
24. A composition as recited in claim 2 wherein said alkyl hydroxycarboxylic acid has the generalized formula HOOC -(R B1)a -( R B2)b -(R B3)c - R B4 where a, b, and c are integers from 0 to 6 and (a+b+c)>0 where R B1, R B2, R
B3 comprise C=O or CYZ, where Y and Z are separately selected from the group of H, OH, CHO, COON, CH3, CH2(OH), CH(OH)2, CH2(COOH), CH(OH)COOH, CH2(CHO) and CH(OH)CHO, so selected that the molecule has a minimum of one OH group when written in its fully hydrated form and R B4 is either H or COOH, including the various stereoisomers and chemically equivalent cyclic, dehydrated, and hydrated forms of these acids and hydrolyzable esters and acetals that form the above compounds in water or the water soluble salts of such alkyl hydroxycarboxylic acids.
25. ~A composition as recited in claim 24 wherein said akyl hydroxycarboxylic acid is chosen from the group consisting of tartaric acid, mesotartaric acid, citric acid, gluconic acid, glucoheptonic acid, ketomalonic acid, saccharic acid and the water soluble salts thereof.

26. ~A composition as recited in claim 2 wherein the said other aqueous system treatment materials is a mixture of orthophosphoric acid or its water-soluble salts and at least one alkyl hydroxycarboxylic acid having the generalized formula HOOC -(R B1)a -(R B2)b -(R B3)c -R B4 where a, b, and c are integers from 0 to 6 and (a+b+c)>p where R B1, R B2, R
B3 comprise C=O or CYZ, where Y and Z are separately selected from the group of H, OH, CHO, COOH, CH3, CH2(OH), CH(OH)2, CH2(COOH), CH(OH)COOH, CH2(CHO) and CH(OH)CHO, so selected that the molecule has a minimum of one OH group when written in its fully hydrated form and R B4 is either H or COOH, including the various stereoisomers and chemically equivalent cyclic, dehydrated, and hydrated forms of these acids and hydrolyzable esters and acetals that form the above compounds in water or the water soluble salts of such alkyl hydroxycarboxylic acids, and the water soluble salts thereof.

27. A composition as recited in claim 26 wherein the hydroxycarboxylic acid is selected from the group consisting of tartaric acid, mesotartaric acid, citric acid, gluonic acid, glucoheptonic acid, ketomalonic acid, saccharic acid and the water soluble salts thereof.

28. A composition as recited in claim 2 wherein said aminohydroxysuccinic acid has the generalized formula wherein R C1 is H or C1 to C4 alkyl, optionally substituted with optionally substituted with -OH, -CO2H, -SO3H, or phenyl, C4 to C7 cycloalkyl, or phenyl which is optionally substituted with -OH or -CO2H, and R C2 is H, C1 to C6 alkyl, optionally substituted with -OH
or -CO2H
(specifically including the moiety -CH(CO2H)CH(OH)(CO2H)); and wherein R C2 is as above, and Z C is selected from the group consisting of i)- (CH2)k wherein k is an integer from 2 to 10, ii) -(CH2) 2 -X C -(CH2)2 wherein X C is -O-, -S-, -NR C3 , wherein R C3 is selected from the group consisting of H, C1 to C6 alkyl, hydroxyalkyl, carboxyalkyl, acyl, and -C(O)OR C4 wherein R C4 is selected from the group consisting of C1 to C6 alkyl or benzyl and a residue having the general formula:
wherein R C2 is as above, iii) a residue having the generalized formula wherein Y is H, C1 to C6 alkyl, alkoxy, halogen, - CO2H, or - SO3H, m is independently 0 or 1, and p is 1 or 2, and iv) a residue having the generalized formula:
wherein R C5 and R C6 are independently H or C1 to C6 alkyl, Q is H or C1 to C6 alkyl, s is 0, 1 or 2, t is independently 0, 1, 2, or 3, q is 0, 1, 2, or 3, and r is 1 or 2 or water soluble salts thereof.

29. The composition as recited in claim 28 wherein the aminohydroxysuccinic acid is selected from the group consisting of iminodi(2-hydroxysuccinic acid), N, N'-Bis(2-hydroxysuccinyl)-1,6-hexanediamine, N,N'-Bis(2-hydroxysuccinyl)-m-xylylenediamine, and the water-soluble salts thereof.

30. A composition as recited in claim 2 wherein said other aqueous system treatment material is a mixture of orthophosphoric acid or its water-soluble salts and at least one aminohydroxysuccinic acid wherein said aminohydroxysuccinic acid has the generalized formula wherein R C1 is H or C1 to C4 alkyl, optionally substituted with optionally substituted with -OH, -CO2H, -SO3H, or phenyl, C4 to C7 cycloalkyl, or phenyl which is optionally substituted with -OH or -CO2H, and R C2 is H, C1 to C6 alkyl, optionally substituted with -OH
or -CO2H
(specifically including the moiety -CH(CO2H)CH(OH)(CO2H)); and wherein R C2 is as above, and Z C is selected from the group consisting of i)- (CH2) k - wherein k is an integer from 2 to 10, ii) -(CH2)2 -X C-(CH2)2 wherein X C is -O-, -S-, -NR C3, wherein R C3 is selected from the group consisting of H, C1 to C6 alkyl, hydroxyalkyl, carboxyalkyl, acyl, and -C(O)OR C4 wherein R C4 is selected from the group consisting of C1 to C6 alkyl or benzyl and a residue having the general formula:
wherein R C2 is as above, iii) a residue having the generalized formula wherein Y is H, C1 to C6 alkyl, alkoxy, halogen, - CO2H, or - SO3H, m is independently 0 or 1, and p is 1 or 2, and iv) a residue having the generalized formula:

wherein R C5 and R C6 are independently H or C1 to C6 alkyl, Q is H or C1 to C6 alkyl, s is 0, 1 or 2, t is independently 0, 1, 2, or 3, q is 0, 1, 2, or 3, and r is 1 or 2 or water soluble salts thereof.

31. A composition as recited in claim 30 wherein the aminohydroxysuccinic acid is selected from the group consisting of iminodi(2-hydroxysuccinic acid), N, N'-Bis(2-hydroxysuccinyl)-1,6-hexanediamine, N,N'-Bis(2-hydroxysuccinyl)-m-xylylenediamine, and the water-soluble salts thereof.

32. A composition as recited in claim 2 wherein the polyepoxysuccinic acid has the generalized formula where 1 ranges from about 2 to about 50, M T is hydrogen or a water soluble cation and R T is hydrogen, C1-4 alkyl or C1-4 substituted alkyl, or water soluble salts thereof.

33. A composition as recited in claim 32 wherein R T is hydrogen and 1 ranges from about 2 to about 10.

34. A composition as recited in claim 32 wherein R T is hydrogen and 1 is from about 4 to about 7.

35. A composition as recited in claim 2 wherein the said other aqueous system treatment material is a mixture of orthophosphoric acid or its water-soluble salts and a polyepoxysuccinic acid having the generalized formula where 1 ranges from about 2 to about 50, M T is hydrogen or a water soluble cation and R T is hydrogen, C1-4 alkyl or C1-4 substituted alkyl, or water soluble salts thereof.

36. A composition as recited in claim 35 wherein said polyepoxysuccinic acid has R T as hydrogen and 1 is from about 2 to about 10.

37. A composition as recited in claim 35 wherein said polyepoxysuccinic acid has R T as hydrogen and 1 is from about 4 to about 7.

38. A composition as recited in claim 2 wherein the modified polyepoxysuccinic acid has the generalized formula wherein R D1, when present, is H, a substituted or non-substituted alkyl or aryl moiety having a carbon chain up to the length where solubility in aqueous solution is lost, or a repeat unit obtained after polymerization of an ethylenically unsaturated compound; R D2 and R D3 each independently are H, C1 to C4 alkyl or C1 to C4 substituted alkyl; Z D is O, S, NH, or NR D1, where R D1 is as described above, n is a positive integer greater than 1; f is a positive integer;
and M D is H, a water soluble cation, or a non-substituted lower alkyl group having from 1 to 3 carbon atoms (when R D1 is not present, Z D may be M D O3S, where M D is as described above).

39. The composition as recited in claim 38 wherein R D1 is the meta-xylylene moiety (meta-CH2-C6H4-CH2-), R D2 and R D3 are both H, Z D is -NH, M D is Na or H, and f=2, and u is a positive integer greater than 1.

40. A composition as recited in claim 2 wherein said monophosphonic acid has the generalized formula wherein R F is a C1 to C12 straight or branched chain alkyl residue, a C2 to C12 straight or branched chain alkenyl residue, a C5 to C12 cycloalkyl residue, a C6 to C10 aryl residue, or a C7 to C12 aralkyl residue, and where R F may additionally be singly or multiply substituted with groups independently selected from the group consisting of hydroxyl, amino, and halogen, or the water soluble salts thereof.

41. A composition as recited in claim 2 wherein said diphosphonic acid has the generalized formula wherein R K is a C1 to C12 straight or branched chain alkylene residue, a C2 to C12 straight or branched chain alkenylene residue, a C5 to C12 cycloalkylene residue, a C6 to C10 arylene residue, or a C7 to C12 aralkylene residue where R K may additionally be singly or multiply substituted with groups independently selected from the group consisting of hydroxyl, amino, and halogen, or the water soluble salts thereof.

42. A composition as recited in claim 41 wherein said diphosphonic acid is 1-hydroxyethane-1,1-diphosphonic acid or the water soluble salts thereof.

43. A composition as recited in claim 2 wherein said phosphonocarboxylic acid has the generalized formulas where R H1 is H, alkyl, alkenyl, or alkinyl radical having 1 to 4 carbon atoms, an aryl, cycloalkyl, or aralkyl radical, or the radical selected from the following:
where R H2 is H, alkyl radical of 1 to 4 carbon atoms, or a carboxyl radical;
and X H is selected from the following:
and where the -PO3H2 group is the phosphono group or the water-soluble salts thereof.

44. A composition as recited in claim 43 wherein said phosphonocarboxylic acid is 2-phosphonobutane-1,2,4-tricarboxylic acid or the water soluble salts thereof.

45. A composition as recited in claim 2 wherein said hydroxyphosphonocarboxylic acid has the generalized formula wherein R E is H, a C1 to C12 straight or branched chain alkyl residue, a C2 to C12 straight or branched chain alkenyl residue, a C5 to C12 cycloalkyl residue, a C6 to C10 aryl residue, or a C7 to C12 aralkyl residue, X E is an optional group, which when present is a C1 to C10 straight or branched chain alkylene residue, a C2 to C10 straight or branched chain alkenylene residue, or a C6 to C10 arylene residue or water soluble salts thereof.

46. A composition as recited in claim 45 wherein said hydroxyphosphonocarboxylic acid is 2-hydroxy-phosphonoacetic acid or the water soluble salts thereof.

47. A composition as recited in claim 2 wherein said aminophosphonic acid has the generalized formula where R G2 is a lower alkylene having from about one to about four carbon atoms, or an amine, hydroxy, or halogen substituted lower alkylene; R G3 is R G2 - PO3H2, H, OH, amino, substituted amino, or R F, where R F is a C1 to C12 straight or branched chain alkyl residue, a C2 to C12 straight or branched chain alkenyl residue, a C5 to C12 cycloalkyl residue, a C6 to C10 aryl residue, or a C7 to C12 aralkyl residue, and where R F may additionally be singly or multiply substituted with groups independently selected from the group consisting of hydroxyl, amino, and halogen, R G4 is R G3 or the group represented by the generalized formula:

where R G5 and R G6 are each independently selected from the group consisting of H, OH, amino, substituted amino, and R F as previously defined; R G7 is R G5, R G6, or the group R G2 -PO3H2 with R G2 as previously defined; v is an integer from 1 to about 15; and w is an integer from 1 through about 14 or water soluble salts thereof.

48. A composition as recited in claim 47 wherein said aminophosphonic acid is diethylenetriamine penta(methylenephosphonic acid) or the water soluble salts thereof.

49. A composition as recited in claim 2 wherein said phosphonomethyl amine oxide has the generalized formula wherein either R A1 is selected from the group consisting of hydrocarbyl, and hydroxy-substituted, alkoxy-substituted, carboxyl-substituted and sulfonyl-substituted hydrocarbyl; and R A2 is selected from the group consisting of hydrocarbyl, and hydroxy-substituted, alkoxy-substituted, carboxyl-substituted and sulfonyl-substituted hydrocarbyl, -CH2PO3H2, and or R A1 and R A2 together form an alicyclic ring having 3 to 5 carbon atoms in the ring or a water-soluble salt of said phosphonomethyl amine oxide, wherein said hydrocarbyl includes alkyl, aryl, and alkaryl groups which do not render the amine oxide insoluble in water.

50. A composition as recited in claim 49 wherein said phosphonomethyl amine oxide is N,N-bis-phosphonomethylethanolamine N-oxide or the water soluble salts thereof.

51. A composition as recited in claim 2 wherein said phosphorus-containing carboxylate is an oligomer, polymer, co-oligomer, or copolymer obtained from the polymerization of one or more unsaturated monomers in the presence of a phosphorus containing compound, said monomers containing one or more carboxyl groups or containing one or more groups that have been transformed after polymerization into carboxyl groups, and in which the resulting phosphorus containing carboxylate contains phosphorus incorporations that are predominantly or exclusively present as end-type phosphino species or the water soluble salts thereof.

52. A composition as recited in claim 2 wherein said phosphorus-containing carboxylate is an oligomer, polymer, co-oligomer, or copolymer obtained from the polymerization of one or more unsaturated monomers in the presence of a phosphorus containing compound, said monomers containing one or more carboxyl groups or containing one or more groups that have been transformed after polymerization into carboxyl groups, and in which the resulting phosphorus containing carboxylate contains phosphorus incorporations that are predominantly or exclusively present as phosphono species or the water soluble salts thereof.

53. A composition as recited in claim 2 wherein said phosphorus-containing carboxylate is an oligomer, polymer, co-oligomer, or copolymer obtained from the polymerization of one or more unsaturated monomers in the presence of a phosphorus containing compound, said monomers containing one or more carboxyl groups or containing one or more groups that have been transformed after polymerization into carboxyl groups, and in which the resulting phosphorus-containing carboxylate contains phosphorus incorporations that are predominantly or exclusively present as dialkylphosphino species or the water soluble salts thereof.

54. A composition as recited in claim 2 wherein said phosphorus-containing carboxylate is an oligomer, polymer, co-oligomer, or copolymer obtained from the polymerization of one or more unsaturated monomers in the presence of a phosphorus containing compound, said monomers containing one or more carboxyl groups or containing one or more groups that have been transformed after polymerization into carboxyl groups, and in which the resulting phosphorus-containing carboxylate contains phosphorus incorporations which are present as a mix of phosphono, end-type phosphino, and dialkylphosphino species or the water soluble salts thereof.
55. A composition as recited in claim 51 wherein said unsaturated monomers are chosen from the group consisting of acrylic acid, maleic acid, maleic anhydride, methacrylic acid, itaconic acid, crotonic acid, vinyl acetic acid, fumaric acid, citraconic acid, mesaconic acid, acrylonitrile, methacrylonitrile, alpha-methylene glutaric acid, cyclohexenedicarboxylic acid, cis-1,2,3,6-tetrahydrophthalic anhydride, 3,6-epoxy-1,2,3,6-tetrahydrophthalic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, bicyclo[2.2.2]-5-octene-2,3-dicarboxylic anhydride, 3-methyl-1,2,6-tetrahydrophthalic anhydride, and 2-methyl-1,3,6-tetrahydrophthalic anhydride.

56. A composition as recited in claim 51 wherein acrylic acid is the sole unsaturated monomer.

57. A composition as recited in claim 51 wherein the sole unsaturated monomer is selected from the group consisting of maleic acid, itaconic acid, and maleic anhydride.
58. A composition as recited in claim 51 wherein one unsaturated monomer is acrylic acid and the other unsaturated monomer is selected from the group consisting of maleic acid, itaconic acid, and maleic anhydride.
59. A composition as recited in claim 52 wherein said unsaturated monomers are selected from the group consisting of acrylic acid, maleic acid, maleic anhydride, methacrylic acid, itaconic acid, crotonic acid, vinyl acetic acid, fumaric acid, citraconic acid, mesaconic acid, acrylonitrile, methacrylonitrile, alpha-methylene glutaric acid, cyclohexenedicarboxylic acid, cis-1,2,3,6-tetrahydrophthalic anhydride, 3,6-epoxy-1,2,3,6-tetrahydrophthalic anhydride, S-norbornene-2,3-dicarboxylic anhydride, bicyclo[2.2.2]-5-octene-2,3-dicarboxylic anhydride, 3-methyl-1,2,6-tetrahydrophthalic anhydride, and 2-methyl-1,3,6-tetrahydrophthalic anhydride.
60. A composition as recited in claim 52 wherein acrylic acid is the sole unsaturated monomer.
61. A composition as recited in claim 52 wherein the sole unsaturated monomer is selected from the group consisting of maleic acid, itaconic acid, and maleic anhydride.

62. A composition as recited in claim 52 wherein one unsaturated monomer is acrylic acid and the other unsaturated monomer is selected from the group consisting of maleic acid, itaconic acid, and maleic anhydride.

63. A composition as recited in claim 53 wherein said unsaturated monomers are seleted from the group consisting of acrylic acid, maleic acid, maleic anhydride, methacrylic acid, itaconic acid, crotonic acid, vinyl acetic acid, fumaric acid, citraconic acid, mesaconic acid, acrylonitrile, methacrylonitrile, alpha-methylene glutaric acid, cyclohexenedicarboxylic acid, cis-1,2,3,6-tetrahydrophthalic anhydride, 3,6-epoxy-1,2,3,6-tetrahydrophthalic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, bicyclo[2.2.2]-5-octene-2,3-dicarboxylic anhydride, 3-methyl-1,2,6-tetrahydrophthalic anhydride, and 2-methyl-1,3,6-tetrahydxophthalic anhydride.

64. A composition as recited in claim 53 wherein acrylic acid is the sole unsaturated monomer.

65. A composition as recited in claim 53 wherein the sole unsaturated monomer is selected from the group consisting of maleic acid, itaconic acid, and maleic anhydride.

66. A composition as recited in claim 53 wherein one unsaturated monomer is acrylic acid and the other unsaturated monomer is selected from the group consisting of maleic acid, itaconic acid, and maleic anhydride.

67. A composition as recited in claim 54 wherein said unsaturated monomers are selected from the group consisting of acrylic acid, maleic acid, maleic anhydride, methacrylic acid, itaconic acid, crotonic acid, vinyl acetic acid, fumaric acid, citraconic acid, mesaconic acid, acrylonitrile, methacrylonitrile, alpha-methylene glutaric acid, cyclohexenedicarboxylic acid, cis-1,2,3,6-tetrahydrophthalic anhydride, 3,6-epoxy-1,2,3,6-tetrahydrophthalic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, bicyclo[2.2.2]-5-octene-2,3-dicarboxylic anhydride, 3-methyl-1,2,6-.tetrahydrophthalic anhydride, and 2-methyl-1,3,6-tetrahydrophthalic anhydride.

68. A composition as recited in claim 54 wherein acrylic acid is the sole unsaturated monomer.

69. A composition as recited in claim 54 wherein the sole unsaturated monomer is selected from the group consisting of maleic acid, itaconic acid, and maleic anhydride.

70. A composition as recited in claim 54 wherein one unsaturated monomer is acrylic acid and the other unsaturated monomer is selected from the group consisting of maleic acid, itaconic acid, and maleic anhydride.

71. A composition as recited in claim 2 wherein said phosphorus-containing carboxylate is a co-oligomer or copolymer obtained from the polymerization of two or more unsaturated monomers in the presence of a phosphorus containing compound, a major proportion of residues (more than 50% by weight) of the phosphorus-containing carboxylate being derived from carboxyl monomers which contain one or more carboxyl groups or which contain one or more groups that have been transformed after polymerization into carboxyl groups, the remaining residues being obtained from non-carboxyl monomers, and in which the resulting phosphorus-containing carboxylate contains phosphorus incorporations that are predominantly or exclusively present as end-type phosphino species or the water soluble salts thereof.

72. A composition as recited in claim 71 wherein the non-carboxyl monomers are selected from the group consisting of 2-acrylamido-2-methylpropanesulfonic, 2-hydroxy-3-(2-propenyloxy)propanesulfonic acid, 2-methyl-2-propene-1-sulfonic acid, allylsulfonic acid, allyloxybenzenesulfonic acid, styrenesulfonic acid, vinylsulfonic acid, allylphosphonic acid, vinylphosphonic acid, isopropenylphosphonic acid, phosphoethyl methacrylate, hydroxyalkyl and C1-C4 alkyl esters of acrylic or methacrylic acid, acrylamides, alkyl substituted acrylamides, allyl alcohol, 2-vinyl pyridine, 4-vinyl pyridine, N-vinylpyrrolidone, N-vinylformamide, N-vinylimidazole, vinyl acetate, hydrolyzed vinyl acetate, and styrene.

73. A composition as recited in claim 71 wherein said carboxyl monomers are selected from the group consisting of acrylic acid, maleic acid, maleic anhydride, methacrylic acid, itaconic acid, crotonic-acid, vinyl acetic acid, fumaric acid, citraconic acid, mesaconic acid, acrylonitrile, methacrylonitrile, alpha-methylene glutaric acid, cyclohexenedicarboxylic acid, cis-1,2,3,6-tetrahydrophthalic anhydride, 3,6-epoxy-1,2,3,6-tetrahydrophthalic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, bicyclo[2.2.2]-5-octene-2,3-dicarboxylic anhydride, 3-methyl-1,2,6-tetrahydrophthalic anhydride, and 2-methyl-1,3,6-tetrahydrophthalic anhydride.

74. A composition as recited in claim 73 wherein the carboxyl monomer is selected from the group consisting of acrylic acid, maleic acid, itaconic acid, and maleic anhydride.

75. A composition as recited in claim 2 wherein said phosphorus-containing carboxylate is a co-oligomer or copolymer obtained from the polymerization of two or more unsaturated monomers in the presence of a phosphorus containing compound, a major proportion of residues (more than 50% by weight) of the phosphorus-containing carboxylate being derived from carboxyl monomers which contain one or more carboxyl groups or which contain one or more groups that have been transformed after polymerization into carboxyl groups, the remaining residues being obtained from non-carboxyl monomers, and in which the resulting phosphorus-containing carboxylate contains phosphorus incorporations that are predominantly or exclusively present as phosphono species or the water soluble salts thereof.

76. A composition as recited in claim 75 wherein the non-carboxyl monomers are chosen from the group consisting of 2-acrylamido-2-methylpropanesulfonic, 2-hydroxy-3-(2-propenyloxy)propanesulfonic acid, 2-methyl-2-propene-1-sulfonic acid, allylsulfonic acid, allyloxybenzenesulfonic acid, styrenesulfonic acid, vinylsulfonic acid, allylphosphonic acid, vinylphosphonic acid, isopropenylphosphonic acid, phosphoethyl methacrylate, hydroxyalkyl and C1-C4 alkyl esters of acrylic or methacrylic acid, acrylamides, alkyl substituted acrylamides, allyl alcohol, 2-vinyl pyridine, 4-vinyl pyridine, N-vinylpyrrolidone, N-vinylformamide, N-vinylimidazole, vinyl acetate, hydrolyzed vinyl acetate, and styrene.

77. A composition as recited in claim 75 wherein said carboxyl monomers are chosen from the group consisting of acrylic acid, maleic acid, maleic anhydride, methacrylic acid, itaconic acid, crotonic acid, vinyl acetic acid, fumaric acid, citraconic acid, mesaconic acid, acrylonitrile, methacrylonitrile, alpha-methylene glutaric acid, cyclohexenedicarboxylic acid, cis-1,2,3,6-tetrahydrophthalic anhydride, 3,6-epoxy-1,2,3,6-tetrahydrophthalic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, bicyclo[2.2.2]-5-octene-2,3-dicarboxylic anhydride, 3-methyl-1,2,6-tetrahydrophthalic anhydride, and 2-methyl-1,3,6-tetrahydrophthalic anhydride.

78. A composition as recited in claim 77 wherein the carboxyl monomer is chosen from the group consisting of acrylic acid, maleic acid, itaconic acid, and maleic anhydride.

79. A composition as recited in claim 2 wherein said phosphorus-containing carboxylate is a co-oligomer, or copolymer obtained from the polymerization two or more unsaturated monomers in the presence of a phosphorus containing compound, a proportion of residues of more than 50% by weight of the entire compound, in the phosphorus-containing carboxylate being derived from monomers containing one or more carboxyl groups or containing one or more groups that have been transformed after polymerization into carboxyl groups, the remaining residues being obtained from monomers which do not contain either carboxyl groups or groups that have been transformed after polymerization into carboxyl groups or non-carboxyl monomers, and in which the resulting phosphorus-containing carboxylate contains phosphorus incorporations that are predominantly or exclusively present as dialkylphosphino species or the water soluble salts thereof.

80. A composition as recited in claim 79 wherein the non-carboxyl monomers are selected from the group consisting of 2-acrylamido-2-methylpropanesulfonic, 2-hydroxy-3-(2-propenyloxy)propanesulfonic acid, 2-methyl-2-propene-1-sulfonic acid, allylsulfonic acid, allyloxybenzenesulfonic acid, styrenesulfonic acid, vinylsulfonic acid, allylphosphonic acid, vinylphosphonic acid, isopropenylphosphonic acid, phosphoethyl methacrylate, hydroxyalkyl and C1-C4 alkyl esters of acrylic or methacrylic acid, acrylamides, alkyl substituted acrylamides, allyl alcohol, 2-vinyl pyridine, 4-vinyl pyridine, N-vinylpyrrolidone, N-vinylformamide, N-vinylimidazole, vinyl acetate, hydrolyzed vinyl acetate, and styrene.

81. A composition as recited in claim 79 wherein said carboxyl monomers are selected from the group consisting of acrylic acid, maleic acid, maleic anhydride, methacrylic acid, itaconic acid, crotonic acid, vinyl acetic acid, fumaric acid, citraconic acid, mesaconic acid, acrylonitrile, methacrylonitrile, alpha-methylene glutaric acid, cyclohexenedicarboxylic acid, cis-1,2,3,6-tetrahydrophthalic anhydride, 3,6-epoxy-1,2,3,6-tetrahydrophthalic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, bicyclo[2.2.2]-5-octene-2,3-dicarboxylic anhydride, 3-methyl-1,2,6-tetrahydrophthalic anhydride, and 2-methyl-1,3,6-tetrahydrophthalic anhydride.

82. A composition as recited in claim 81 wherein the carboxyl monomer is selected from the group consisting of acrylic acid, maleic acid, itaconic acid, and maleic anhydride. 83.
A composition as recited in claim 2 wherein said phosphorus-containing carboxylate is a co-oligomer or copolymer obtained from the polymerization of two or more unsaturated monomers in the presence of a phosphorus containing compound, a major proportion of residues (more than 50% by weight) of the phosphorus-containing carboxylate being derived from carboxyl monomers which contain one or more carboxyl groups or which contain one or more groups that have been transformed after polymerization into carboxyl groups, the remaining residues being obtained from non-carboxyl monomers, and in which the resulting phosphorus-containing carboxylate contains phosphorus incorporations that are present as a mixture of phosphono, end-type phosphino, and dialkylphosphino species or the water soluble salts thereof.

84. A composition as recited in claim 83 wherein the non-carboxyl monomers are selected from the group consisting of 2-acrylamido-2-methylpropanesulfonic, 2-hydroxy-3-(2-propenyloxy)propanesulfonic acid, 2-methyl-2-propene-1-sulfonic acid, allylsulfonic acid, allyloxybenzenesulfonic acid, styrenesulfonic acid, vinylsulfonic acid, allylphosphonic acid, vinylphosphonic acid, isopropenylphosphonic acid, phosphoethyl methacrylate, hydroxyalkyl esters of acrylic or methacrylic acid, C1-C4 alkyl esters of acrylic or methacrylic acid, acrylamides, alkyl substituted acrylamides, allyl alcohol, 2-vinyl pyridine, 4-vinyl pyridine, N-vinylpyrrolidone, N-vinylformamide, N-vinylimidazole, vinyl acetate, hydrolyzed vinyl acetate, and styrene.

85. A composition as recited in claim 83 wherein said carboxyl monomers are chosen from the group consisting of acrylic acid, maleic acid, maleic anhydride, methacrylic acid, itaconic acid, crotonic acid, vinyl acetic acid, fumaric acid, citraconic acid, mesaconic acid, acrylonitrile, methacrylonitrile, alpha-methylene glutaric acid, cyclohexenedicarboxylic acid, cis-1,2,3,6-tetrahydrophthalic anhydride, 3,6-epoxy-1,2,3,6-tetrahydrophthalic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, bicyclo[2.2.2]-5-octene-2,3-dicarboxylic anhydride, 3-methyl-1,2,6-tetrahydrophthalic anhydride, and 2-methyl-1,3,6-tetrahydrophthalic anhydride.

86. A composition as recited in claim 85 wherein the carboxyl monomer is selected from the group consisting of acrylic acid, maleic acid, itaconic acid, and maleic anhydride.

87. A composition as recited in claim 2 wherein said phosphorus-containing carboxylate is a phosphonic polymer having the generalized formula wherein X j is H, an alkali metal atom, an alkaline earth metal atom, or an ammonium or amine residue; and R j1 is a copolymer residue comprising two different residues wherein z is an integer ranging from 2 to 100, and wherein, in the first residue, R j2 is -COOH, and in the second residue, R j2 is -CONHC(CH3)2CH2SO3X j wherein X j is as hereinbefore defined.

88. A composition as recited in claim 2 wherein the aqueous system treatment material is a composition of up to 50% by weight of a phosphonosuccinic acid, based on the weight of the composition, a phosphonated dimer of alkali metal maleate, not more than a minor proportion by weight, based on the weight of the dimer, of higher phosphonated oligomers of maleate;
and from 0.5 to 5% by weight of the composition of an alkali metal phosphate.

89. A composition as recited in claim 2 wherein the long chain fatty acid derivative of a sarcosine is chosen to be N-Lauroylsarcosine or the water soluble salts thereof.

90. A composition as recited in claim 1 wherein the composition includes water.

91. A composition as recited in claim 2 wherein the composition additionally includes water.

92. A composition as recited in claim 2 wherein said composition additionally contains at least one additive chosen from the group consisting of:
i) one or more dispersants ii) one or more copper corrosion inhibitors iii) one or more aluminum corrosion inhibitors iv) one or more water-soluble metal salts of metals chosen from the group zinc, manganese, aluminum, tin, nickel, yttrium, and the rare earth metals v) one or more water-soluble organic metal chelates of metals ions chosen from the group zinc, manganese, aluminum, tin, nickel, yttrium, and the rare earth metals, where the organic chelant is chosen to impart a desired level of water solubility of the metal ion vi) one or more scale control agents vii) one or more sequestering agents viii) one or more anti-foaming agents ix) one or more oxidizing biocides x) one or more non-oxidizing biocides xi) one or more water-soluble alcohols capable of lowering the freezing point of an aqueous system xii) one or more ionic freezing point depressants xiii) one or more p H adjusting agents xiv) one or more inert tracers xv) one or more active tracers xvi) one or more water insoluble organic lubricants xvii) one or more water soluble lubricants xviii) one or more surfactants xix) one or more calcium hardness adjusting agents, and xx) one or more coloring agents 93. A composition as recited in claim 92 wherein the composition additionally includes water.

94. A composition as recited in claim 92 where the dispersant is a water-soluble sulfonated polymer or copolymer obtained from the polymerization of one or more ethylenically unsaturated monomers.

95. A composition as recited in claim 94 where the water-soluble sulfonated copolymer is about a 3:1 weight ratio copolymer of acrylic acid and allyl hydroxy propyl sulfonate ether or the water soluble salts thereof.
96. A composition as recited in claim 92 where the dispersant is a copolymer of diiosbutylene and malefic anhydride with molecular weight < 10,000 or its water soluble salts.
97. A composition as recited in claim 92 where the copper corrosion inhibitor is tolyltriazole.
98. A composition as recited in claim 92 where the copper corrosion inhibitor is a mixed tolyltriazole composition including at least 65% of the 5-methylbenzotriazole isomer by weight.
99. A composition as recited in claim 92 where the copper corrosion inhibitor is benzotriazole.
100. A composition as recited in claim 92 where the copper corrosion inhibitor is mercaptobenzothiazole.
101. A composition as recited in claim 92 where the copper corrosion inhibitor is an akyl or alkoxy substituted benzotriazole wherein the substitution occurs on the 4 or 5 position of the benzene ring.
102. A composition as recited in claim 101 wherein the substituent is chosen from the group consisting of a n-butyl and hexyloxy.
103. A composition as recited in claim 92 where the copper corrosion inhibitor is 1-phenyl-5-mercaptotetrazole.
104. A composition as recited in claim 92 where the copper corrosion inhibitor is a halogen-tolerant azole.
105. A composition as recited in claim 104 where the halogen-tolerant azole is chloro-tolyltriazole.
106. A composition as recited in claim 92 where the aluminum corrosion inhibitor is a water-soluble nitrate salt.
107. A composition as recited in claim 106 where the water-soluble nitrate salt is sodium nitrate.
108. A composition as recited in claim 92 where the water-soluble metal salt is obtained from zinc.
109. A composition as recited in claim 108 where the zinc salt is the sulfate, chloride, acetate, or nitrate salt.

110. A composition as recited in claim 92 where the metal salt is obtained from manganese in the +2 oxidation state.
111. A composition as recited in claim 110 where the manganese salt state is the sulfate, chloride, acetate, or nitrate salt.
112. A composition as recited in claim 92 where the metal salt is obtained from lanthanum or a mixture of rare earth metals containing lanthanum.
113. A composition as recited in claim 112 where the lanthanum salt or mixture of rare earth metal salts containing lanthanum are independently selected from the group consisting of sulfate, chloride, acetate, and nitrate salts.
114. A composition as recited in claim 92 where the sequestering agent is selected from the group consisting of ethylenediaminetetra(acetic acid) nitrolotriacetic acid, N,N-di(2-hydroxyethyl)glycine and the water soluble salts thereof.
115. The composition as recited in claim 2 wherein the alkali metal silicate is sodium metasilicate.
116. A composition as recited in claim 92 where the anti-foaming agent is selected from the group consisting of silicones, polydimethylsiloxanes, distearylsebacamide, distearyladipamide, fatty alcehols; and ethylene oxide condensates of fatty alcohols.
117. A composition as recited in claim 92 where the oxidizing biocide is selected from the group consisting of chorine, hypochlorite, bromine, hypobromite, chlorine donor compounds, bromine donor compounds, peracetic acid, inorganic peroxides and peroxide generators, chlorine dioxide, ozone and mixtures thereof.
118. A composition as recited in claim 92 where the non-oxidizing biocide is selected from the group consisting of amines, quaternary ammonium compounds, 2-bromo-2-nitropropane-1,3-diol, .beta.-bromonitrostyrene, dodecylguanidine hydrochloride, 2,2-dibromo-3-nitrilopropionamide, gluteraldhyde, chlorophenols, sulphones, methylene bis thiocyanates, methylene bis carbamates, isothiazolones, brominated propionamides, triazines, phosphonium compounds, organometallic compounds and mixtures thereof.
119. A composition as recited in claim 92 where the non-oxidizing biocide is a mixture of (a) 2-bromo-2-nitropropane-1,3-diol (BNPD) and (b) a mixture of about 75% 5-chloro-2-methyl-4-isothiazolin-3-one and about 25% 2-methyl-4-isothiazolin-3-one, the weight ratio said BNPD (a) to said mixture (b) being about 16:1 to about 1:1.

120. A composition as recited in claim 92 where the water-soluble alcohol freezing point depressant is selected from the group consisting of ethylene glycol, propylene glycol, ethanol, glycerol, isopropanol, methanol and mixtures thereof.
121. A composition as recited in claim 92 where the ionic freezing point depressant is selected from the group consisting of calcium chloride, sodium chloride, lithium bromide, and lithium chloride.
122. A composition as recited in claim 92 where the pH adjusting agent is selected from the group consisting of sodium hydroxide, potassium hydroxide, lithium hydroxide, hydrochloric acid, sulfuric acid, nitric acid, carbon dioxide, ammonia, organic acids such as oxalic acid, alkali metal carbonates, and akali metal bicarbonates.
123. A composition as recited in claim 92 where the inert tracer is selected from the group consisting of soluble lithium salts, transition metals, and fluorescent materials.
124. A composition as recited in claim 92 where the active tracer is selected from the group consisting of fluorescently tagged polymers, polymers containing a photo-inert, latently detectable moiety, water soluble molybdate salts, and azole-based copper corrosion inhibitors.
125. A composition as recited in claim 92 where the water insoluble organic lubricant is selected from the group consisting of naturally occurring oils and synthetic oils.
126. A composition as recited in claim 92 where the surfactant is selected from the group consisting of anionic, cationic, amphoteric, and nonionic surfactants.
127. A composition as recited in claim 92 where the calcium hardness adjusting agent is selected from the group consisting of the bicarbonate, carbonate, chloride, sulfate, and acetate salts of calcium, calcium hydroxide and calcium oxide.
128. A composition as recited in claim 92 where the coloring agent is a water soluble dye.
129. A composition as recited in claim 2 wherein said monofluorophosphate is sodium monofluorophosphate.
130. A method for controlling the corrosion of metals in contact with an aqueous system having a pH of about 6 or greater which comprises introducing into said system a combination of:
(a) a tetrazolium compound of the formula:

wherein R1, R2 and R3 are selected from the group consisting of lower alkyl, branched lower alkyl, aryl, substituted aryl, alkylaryl, substituted alkylaryl and heterocyclic substituted aryl, with the proviso that neither R1, R2, or R3 contain more than 14 carbon atoms;
and n is 1 or 2, such tetrazolium compound optionally having associated water soluble ionic species if needed to obtain a neutral charge, and (b) at least one other aqueous system treatment material chosen so that the material does not substantially reduce the tetrazolium compound.
131. The method as recited in claim 130 wherein said other aqueous system treatment material is selected from the group consisting of inorganic phosphates, borates, nitrites, compounds that release a metal anion in water, 2,3-dihydroxybenzoic acid, 1,10-phenanthroline, polycarboxylates, hydrocarbyl polycarboxylates, akyl hydroxycarboxylic acids, aminohydroxysuccinic acids, carboxyamines, polyepoxysuccinic acids, modified polyepoxysuccinic acids, monophosphonic acids, diphosphonic acids, phosphonocarboxylic acids, hydroxyphosphonocarboxylic acids, aminophosphonic acids, phosphonomethylamine oxides, polymeric amine oxides, polyetherpolyaminomethylene phosphonates, polyetherpolyamino-methylene phosphonate N-oxides, iminoakylenephosphonic acids, long chain fatty acid derivatives of sarcosine; telomeric, co-telomeric, polymeric, or copolymeric phosphorus-containing carboxylates, alkali metal silicates, monofluorophosphate, amines, diamines, alkanolamines, ether amines, fatty amines and diamines, quaternized amines, oxyalkylated amines, akyl pyridines, tetrazoles, imidazoline and substituted imidazolines, amidoamines, polyamines, polyakylenepolyamines, alkyl derivatives of benzene sulfonic acid, benzoates and substituted benzoates, aminobenzoates, salicylates, dimer-trimer acids, petroleum oxidates, borogluconates; lignins, lignosulfonates, tannins;
straight chain C5-C11 monocarboxylates and C4-C15 .alpha.,.omega.-dicarboxylates; amine salts of carboxylic acids and mercaptocarboxylic acids, amino acids, polyamino acids, hydroxyether acids and related lactone compounds, N-acyliminodiacetic acids; triazine di- and tri-carboxylic acis, phospho-and phosphate esters; and monofluorophosphates; water soluble salts thereof, and mixtures thereof.
132. A method as recited in claim 130 wherein said tetrazolium compound is selected from the group consisting of the water soluble salts of Nitro Blue Tetrazolium (2,2'-Di-p-nitrophenyl-5,5'-distyryl-3,3'-[3,3'-dimethoxy-4,4'-biphenylene]
ditetrazolium), Distyryl Nitroblue Tetrazolium (2,2'-Di-p-nitrophenyl-5,5'-distyryl-3,3'-[3,3'-dimethoxy-4,4'-biphenylene] ditetrazolium), Tetranitro Blue Tetrazolium (3,3'-(3,3'-Dimethoxy-4,4'-biphenylene)-bis-[2,5-p-nitrophenyl-2H-tetrazolium) and Iodonitro Tetrazolium (2-(4-lodophenyl)-3-(4-nitrophenyl)-5-phenyltetrazolium).
133. A method as recited in claim 131 wherein said tetrazolium compound is selected from the group consisting of the water soluble salts of Nitro Blue Tetrazolium (2,2'-Di-p-nitrophenyl-5,5'-distyryl-3,3'-[3,3'-dimethoxy-4,4'-biphenylene]
ditetrazolium), Distyryl Nitroblue Tetrazolium (2,2'-Di-p-nitrophenyl-5,5'-distyryl-3,3'-[3,3'-dimethoxy-4,4'-biphenylene] ditetrazolium);-Tetranitro Blue Tetrazolium (3,3'-(3,3'-Dimethoxy-4,4'-biphenylene)-bis-[2,5-p-nitrophenyl-2H-tetrazolium) and Iodonitro Tetrazolium (2-(4-lodophenyl)-3-(4-nitrophenyl)-S-phenyltetrazolium).
134. A method as recited in claim 130 wherein said water soluble ionic species are anions selected from the group consisting of halogens, nitrates, nitrites, carbonates, bicarbonates, sulfates, phosphates, and transition metal oxygenates.
135. A method as recited in claim 134 wherein said halogens are selected from the group consisting of chlorides, fluorides, bromides and iodides.
136. A method as recited in claim 135 wherein said halogen is chloride.
137. A method as recited in claim 134 wherein said transition metal oxygenate is selected from the group consisting of molybdate, chromate, and tungstate.
138. A method as recited in claim 137 wherein said transition metal oxygenate is molybdate.
139. A method as recited in claim 131 wherein said inorganic phosphates are orthophosphates, polyphosphates, water soluble salts thereof and mixtures thereof.

140. A method as recited in claim 131 wherein said inorganic phosphates are a mixture of orthophosphoric acid and pyrophosphoric acid or the water-soluble salts thereof.
141. A method as recited in claim 131 wherein said borate is a water-soluble borate selected from the group consisting of tetraborates, metaborates, and orthoborates. 142. A
method as recited in claim 141 wherein said water-soluble borate is sodium tetraborate or a hydrate of sodium tetraborate.
143. A method as recited in claim 131 wherein said nitrite is sodium nitrite.
144. A method as recited in claim 131 wherein the metal anion releasing compounds are selected from the group consisting of the water soluble salts of molybdate, tungstate, vanadate, metavanadate, and chromate.
145. A method as recited in claim 144 wherein the water soluble salt of a molybdate is sodium molybdate or a hydrate of sodium molybdate.
146. A method as recited in claim 131 wherein said polycarboxylates comprise aliphatic compounds containing between about 4 and about 20 carbon atoms which are multiply substituted with carboxylate groups or water soluble salts thereof.
147. A method as recited in claim 146 wherein said polycarboxylate is 1,2,3,4-butanetctracarboxylic acid.
148. A method as recited in claim 131 wherein said polycarboxylate is a homopolymer obtained from the polymerization of an ethylenically unsaturated monomer containing one or more carboxyl groups.
149. A method as recited in claim 148 wherein said homopolymer is polyacrylic acid or its water soluble salts.
150. A method as recited in claim 148 wherein said homopolymer is polymaleic acid or its water soluble salts.
151. A method as recited in claim 148 wherein said homopolymer is polymaleic anhydride or its water soluble salts.
152. A method as recited in claim 131 wherein said polycarboxylate is a copolymer obtained from the polymerization of two or more different ethylenically unsaturated monomers, each of said monomers containing one or more carboxyl groups.
153. A method as recited in claim 131 wherein said alkyl hydroxycarboxylic acid has the generalized formula HOOC -(R B1)a -(R B2)b -(R B2)c - R B4 where a, b, and c are integers from 0 to 6 and (a+b+c)>0 where R B1, R B2, RB3 comprise C=O or CYZ, where Y and Z are separately selected from the group consisting of H, OH, CHO, COOH, CH3, CH2(OH), CH(OH)2, CH2(COOH), CH(OH)COOH, CH2(CHO) and CH(OH)CHO, so selected that the molecule has a minimum of one OH group when written in its fully hydrated form and R B4 is either H or COOH, including the various stereoisomers and chemically equivalent cyclic, dehydrated, and hydrated forms of these acids and hydrolyzable esters and acetals that form the above compounds in water or the water soluble salts of such alkyl hydroxycarboxylic acids.
154. A method as recited in claim 153 wherein said akyl hydroxycarboxylic acid is chosen from the group consisting of tartaric acid, mesotartaric acid, citric acid, gluconic acid, glucoheptonic acid, ketomalonic acid, saccharic acid and the water soluble salts thereof.
155. A method as recited in claim 131 wherein the said other aqueous system treatment materials is a mixture of orthophosphoric acid or its water-soluble salts and at least one alkyl hydroxycarboxylic acid having the generalized formula:
HOOC -(R B1)a -(R B2)b -(R B3)c - R B4 where a, b, and c are integers from 0 to 6 and (a+b+c)>0 where R B1, R B2, R
B3 comprise C=O or CYZ, where Y and Z are separately selected from the group of H, OH, CHO, COOH, CH3, CH2(OH), CH(OH)2, CH2(COOH), CH(OH)COOH, CH2(CHO) and CH(OH)CHO, so selected that the molecule has a minimum of one OH group when written in its fully hydrated form and RB4 is either H or COOH, including the various stereoisomers and chemically equivalent cyclic, dehydrated, and hydrated forms of these acids and hydrolyzable esters and acetals that form the above compounds in water or the water soluble salts of such alkyl hydroxycarboxylic acids, and the water soluble salts thereof.
156. A method as recited in claim 155 wherein the hydroxycarboxylic acid is selected from the group consisting of tartaric acid, mesotartaric acid, citric acid, gluonic acid, glucoheptonic acid, ketomalonic acid, saccharic acid and the water soluble salts thereof.
157. A method as recited in claim 131 wherein said aminohydroxysuccinic acid has the generalized formula wherein R C1, is H or C1 to C4 alkyl, optionally substituted with -OH, -CO2H, -SO3H, or phenyl, C4 to C7 cycloalkyl, or phenyl which is optionally substituted with -OH or -CO2H, and R C2 is H, C1 to C6 alkyl, optionally substituted with -OH or -CO2H (specifically including the moiety -CH(CO2H)CH(OH)(CO2H)); and wherein R c2 is as above, and Z c is selected from the group consisting of i)- (CH2)k wherein k is an integer from 2 to 10, ii) -(CH2)2-X c-(CH2)2 wherein X c is -O-, -S-, -NR C3-, wherein RC3 is selected from the group consisting of H, C1 to C6 alkyl, hydroxyalkyl, carboxyalkyl, acyl, and -C(O)ORC4 wherein R C4 is selected from the group consisting of C to C6 alkyl or benzyl and a residue having the general formula:
wherein RC2 is as above, iii) a residue having the generalized formula wherein Y is H, C1 to C6 alkyl, alkoxy, halogen, - CO2H, or - SO3H, m is independently 0 or 1, and p is 1 or 2, and iv) a residue having the generalized formula:
wherein R C5 and R C6 are independently H or C1 to C6 alkyl, Q is H or C1 to C6 alkyl, s is 0, 1 or 2, t is independently 0, 1, 2, or 3, q is 0, 1, 2, or 3, and r is 1 or 2 or water soluble salts thereof.
158. A method as recited in claim 157 wherein the aminohydroxysuccinic acid is selected from the group consisting of iminodi(2-hydroxysuccinic acid), N, N'-Bis(2-hydroxysuccinyl)-1,6-hexanediamine, N,N'-Bis(2-hydroxysuccinyl)-m-xylylenediamine, or the water-soluble salts thereof.
159. A method as recited in claim 131 wherein said other aqueous system treatment material is a mixture of orthophosphoric acid or its water-soluble salts and at least one aminohydroxysuccinic acid wherein said aminohydroxysuccinic acid has the generalized formula wherein RC1, is H or C1 to C4 alkyl, optionally substituted with optionally substituted with -OH, -CO2H, -SO3H, or phenyl, C4 to C7 cycloalkyl, or phenyl which is optionally substituted with -OH or -CO2H, and RC2 is H, C1 to C6 alkyl, optionally substituted with -OH or (specifically including the moiety -CH(CO2H)CH(OH)(CO2H)); and wherein RC2 is as above, and Z c is selected from the group consisting of i)- (CH2)k wherein k is an integer from 2 to 10, ii) -(CH2)2 X c-(CH2)2 wherein X c is -O-, -S-, or -NR C3, wherein RC3 is selected from the group consisting of H, C1 to C6 alkyl, hydroxyalkyl, carboxyalkyl, acyl, -C(O)ORC4 wherein RC4 is selected from the group consisting of C1 to C6 alkyl or benzyl and a residue having the general formula:

wherein R C2 is as above, iii) a residue having the generalized formula wherein Y is H, C1 to C6 alkyl, alkoxy, halogen, -CO2H, or - SO3H, m is independently 0 or 1, and p is 1 or 2, and iv) a residue having the generalized formula:
wherein RC5 and RC6 are independently H or C1 to C6 alkyl, Q is H or C1 to C6 alkyl, s is 0, 1 or 2, t is independently 0, 1, 2, or 3, q is 0, 1, 2, or 3, and r is 1 or 2 or water soluble salts thereof.
160. A method as recited in claim 159 wherein the aminohydroxysuccinic acid is selected from the group consisting of iminodi(2-hydroxysuccinic acid), N, N'-Bis(2-hydroxysuccinyl)-1,6-hexanediamine, N,N'-Bis(2-hydroxysuccinyl)-m-xylylenediamine, and the water-soluble salts thereof.
161. A method as recited in claim 131 wherein the polyepoxysuccinic acid has the generalized formula:

where 1 ranges from about 2 to about 50, M T is hydrogen or a water soluble cation and R T is hydrogen, C1-4 alkyl or C1-4 substituted alkyl.
162. A method as recited in claim 161 wherein R T is hydrogen and 1 ranges from about 2 to about 10.
163. A method as recited in claim 161 wherein R T is hydrogen and 1 is from about 4 to about 7.
164. A method as recited in claim 131 wherein the said other aqueous system treatment material is a mixture of orthophosphoric acid or its water-soluble salts and a polyepoxysuccinic acid having the generalized formula:
where 1 ranges from about 2 to about 50, M T is hydrogen or a water soluble cation and R T is hydrogen, C1-4 alkyl or C1-4 substituted alkyl, or the water soluble salts thereof.
165. A method as recited in claim 164 wherein said polyepoxysuccinic acid has R T
as hydrogen and 1 is from about 2 to about 10.
166. A method as recited in claim 164 wherein said polyepoxysuccinic acid has R T
as hydrogen and 1 is from about 4 to about 7.
167. A method as recited in claim 131 wherein the modified polyepoxysuccinic acid has the generalized formula wherein R D1, when present, is H, a substituted or non-substituted alkyl or aryl moiety having a carbon chain up to the length where solubility in aqueous solution is lost, or a repeat unit obtained after polymerization of an ethylenically unsaturated compound; R D2 and R D3 each independently are H, C1 to C4 alkyl or C1 to C4 substituted alkyl; Z D is O, S, NH, or NR D1, where R D1, is as described above, n is a positive integer greater than 1; f is a positive integer;
and Mp is H, a water soluble cation, or a non-substituted lower alkyl group having from 1 to 3 carbon atoms (when R D1, is not present, Z D may be M D O3S, where M D is as described above).
168. A method as recited in claim 167 wherein R DI, is the meta-xylylene moiety (meta-CH2-C6H4 CH2-), R D2 and R D3 are both H, Z D is -NH, M D is Na or H, and f=2, and a is a positive integer greater thank.
169. The method as recited in claim 131 wherein said monophosphonic acid has the generalized formula:
wherein R F is a C1 to C12 straight or branched chain alkyl residue, a C2 to C12 straight or branched chain alkenyl residue, a C5 to C12 cycloalkyl residue, a C6 to C10 aryl residue, or a C7 to C12 aralkyl residue, and where R F may additionally be singly or multiply substituted with groups independently chosen from hydroxyl, amino, or halogen, or the water soluble salts thereof.
170. A method as recited in claim 131 wherein said diphosphonic acid has the generalized formula:

wherein R K is a C1 to C12 straight or branched chain alkylene residue, a C2 to C12 straight or branched chain alkenylene residue, a C5 to C12 cycloalkylene residue, a C6 to C10 arylene residue, or a C7 to C12 aralkylene residue where R K may additionally be singly or multiply substituted with groups independently chosen from hydroxyl, amino, or halogen, or the water soluble salts thereof.
171. A method as recited in claim 170 wherein said diphosphonic acid is is 1-hydroxyethane-1,1-diphosphonic acid or the water soluble salts thereof.
172. A method as recited in claim 131 wherein said phosphonocarboxylic acid has the generalized formulas where R H1, is H, an alkyl, alkenyl, or alkinyl radical having 1 to 4 carbon atoms, an aryl, cycloalkyl, or aralkyl radical, or the radical selected from the following:
where R H2 is H, alkyl radical of 1 to 4 carbon atoms, or a carboxyl radical;
and X H is selected from the following:

and where the -PO3H2 group is the phosphono group or the water-soluble salts thereof.
173. A method as recited in claim 172 wherein said phosphonocarboxylic acid is phosphonobutane-1,2,4-tricarboxylic acid or the water soluble salts thereof.
174. A method as recited in claim 131 wherein said hydroxyphosphonocarboxylic acid has the generalized formula wherein RE is H, a C1 to C12 straight or branched chain alkyl residue, a C2 to C12 straight or branched-chain alkenyl residue; a C5 to C12 cycloalkyl residue, a C6 to C10 aryl residue, or a C7 to C12 aralkyl residue, X E is an optional group, which when present is a C1 to C10 straight or branched chain alkylene residue, a C2 to C10 straight or branched chain alkenylene residue, or a C6 to C10 arylene residue or water soluble salts thereof.
175. A method as recited in claim 174 wherein said hydroxyphosphonocarboxylic acid is 2-hydroxy-phosphonoacetic acid or the water soluble salts thereof.
176. A method as recited in claim 131 wherein said aminophosphonic acid has the generalized formula:

where R G2 is a lower alkylene having from about one to about four carbon atoms, or an amine, hydroxy, or halogen substituted lower alkylene; R G3 is R G2 ~ PO3H2, H, OH, amino, substituted amino, or R F, where R F is a C1 to C12 straight or branched chain alkyl residue, a C2 to C12 straight or branched chain alkenyl residue, a C5 to C12 cycloalkyl residue, a C6 to C10 aryl residue, or a C7 to C12 aralkyl residue, and where R F may additionally be singly or multiply substituted with groups independently selected from the group consisting of hydroxyl, amino, and halogen, R G4 is R G3 or the group represented by the generalized formula:
where R G5 and R G6 are each independently selected from the group consisting of H, OH, amino, substituted amino, and R F as previously defined; R G7 is R G5, R G6, or the group R G2-PO3H2 with R G2 as previously defined; v is an integer from 1 to about 15; and w is an integer from 1 through about 14 or water soluble salts thereof.

177. A method as recited in claim 176 wherein said aminophosphonic acid is diethylenetriamine penta(methylenephosphonic acid) or the water soluble salts thereof.

178. A method as recited in claim 131 wherein said phosphonomethyl amine oxide has the generalized formula wherein either R A1 is selected from the group consisting of hydrocarbyl, and hydroxy-substituted, alkoxy-substituted, carboxyl-substituted and sulfonyl-substituted hydrocarbyl; and R A2 is selected from the group consisting of hydrocarbyl, and hydroxy-substituted, alkoxy-substituted, carboxyl-substituted and sulfonyl-substituted hydrocarbyl, -CH2PO3H2, and or R A1 and R A2 together form an alicyclic ring having 3 to 5 carbon atoms in the ring or a water-soluble salt of said phosphonomethyl amine oxide. Hydrocarbyl includes alkyl, aryl, and alkaryl groups which do not render the amine oxide insoluble in water.

179. A method as recited in claim 178 wherein said phosphonomethyl amine oxide is N,N-bis-phosphonomethylethanolamine N-oxide or the water soluble salts thereof.

180. A method as recited in claim 131 wherein said phosphorus-containing carboxylate is an oligomer, polymer, co-oligomer, or copolymer obtained from the polymerization of one or more unsaturated monomers in the presence of a phosphorus containing compound, said monomers containing one or more carboxyl groups or containing one or more groups that have been transformed after polymerization into carboxyl groups, and in which the resulting phosphorus containing carboxylate contains phosphorus incorporations that are predominantly or exclusively present as end-type phosphino species or the water soluble salts thereof.

181. A method as recited in claim 131 wherein said phosphorus-containing carboxylate is an oligomer, polymer, co-oligomer, or copolymer obtained from the polymerization of one or more unsaturated monomers in the presence of a phosphorus containing compound, said monomers containing one or more carboxyl groups or containing one or more groups that have been transformed after polymerization into carboxyl groups, and in which the resulting phosphorus containing carboxylate contains phosphorus incorporations that are predominantly or exclusively present as phosphono species or the water soluble salts thereof.

182. A method as recited in claim 131 wherein said phosphorus-containing carboxylate is an oligomer, polymer, co-oligomer, or copolymer obtained from the polymerization of one or more unsaturated monomers in the presence of a phosphorus containing compound, said monomers containing one or more carboxyl groups or containing one or more groups that have been transformed after polymerization into carboxyl groups, and in which the resulting phosphorus-containing carboxylate contains phosphorus incorporations that are predominantly or exclusively present as dialkylphosphino species or the water soluble salts thereof.

183. A method as recited in claim 131 wherein said phosphorus-containing carboxylate is an oligomer, polymer, co-oligomer, or copolymer obtained from the polymerization of one or more unsaturated monomers in the presence of a phosphorus containing compound, said monomers containing one or more carboxyl groups or containing one or more groups that have been transformed after polymerization into carboxyl groups and in which the resulting phosphorus-containing carboxylate contains phosphorus incorporations which are present as a mix of phosphono, end-type phosphino, and dialkylphosphino species or the water soluble salts thereof.

184. A method as recited in claim 180 wherein said unsaturated monomers are chosen from the group consisting of acrylic acid, maleic acid, maleic anhydride, methacrylic acid, itaconic acid, crotonicacid; vinyl acetic acid, fumaric acid, citraconic acid, mesaconic acid, acrylonitrile, methacrylonitrile, alpha-methylene glutaric acid, cyclohexenedicarboxylic acid, cis-1,2,3,6-tetrahydrophthalic anhydride, 3,6-epoxy-1,2,3,6-tetrahydrophthalic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, bicyclo[2.2.2]-5-octene-2,3-dicarboxylic anhydride, 3-methyl-1,2,6-tetrahydrophthalic anhydride, and 2-methyl-1,3,6-tetrahydrophthalic anhydride.

185. A method as recited in claim 180 wherein acrylic acid is the sole unsaturated monomer.

186. The method as recited in claim 180 wherein the sole unsaturated monomer is selected from the group consisting of maleic acid, itaconic acid, and maleic anhydride.

187. A method as recited in claim 180 wherein one unsaturated monomer is acrylic acid and the other unsaturated monomer is selected from the group consisting of maleic acid, itaconic acid, and maleic anhydride.

188. A method as recited in claim 181 wherein said unsaturated monomers are selected from the group consisting of acrylic acid, maleic acid, maleic anhydride, methacrylic acid, itaconic acid, crotonic acid, vinyl acetic acid, fumaric acid, citraconic acid, mesaconic acid, acrylonitrile, methacrylonitrile, alpha-methylene glutaric acid, cyclohexenedicarboxylic acid, cis-1,2,3,6-tetrahydrophthalic anhydride, 3,6-epoxy-1,2,3,6-tetrahydrophthalic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, bicyclo[2.2.2]-5-octene-2,3-dicarboxylic anhydride, 3-methyl-1,2,6-tetrahydrophthalic anhydride, and 2-methyl-1,3,6-tetrahydrophthalic anhydride.

189. A method as recited in claim 181 wherein acrylic acid is the sole unsaturated monomer.

190. A method as recited in claim 181 wherein the sole unsaturated monomer is selected from the group consisting of maleic acid, itaconic acid, and maleic anhydride.

191. A method as recited in claim 181 wherein one unsaturated monomer is acrylic acid and the other unsaturated monomer is selected from the group consisting of maleic acid, itaconic acid, and maleic anhydride.

192. A method as recited in claim 182 wherein said unsaturated monomers are selected from the group consisting of acrylic acid, maleic acid, maleic anhydride, methacrylic acid, itaconic acid, crotonic acid, vinyl acetic acid, fumaric acid, citraconic acid, mesaconic acid, acrylonitrile, methacrylonitrile, alpha-methylene glutaric acid, cyclohexenedicarboxylic acid, cis-1,2,3,6-tetrahydrophthalic anhydride, 3,6-epoxy-1,2,3,6-tetrahydrophthalic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, bicyclo[2.2.2]-5-octene-2,3-dicarboxylic anhydride, 3-methyl-1,2,6-tetrahydrophthalic anhydride, and 2-methyl-1,3,6-tetrahydrophthalic anhydride.

193. A method as recited in claim 182 wherein acrylic acid is the sole unsaturated monomer.

194. A method as recited in claim 182 wherein the sole unsaturated monomer is selected from the group consisting of maleic acid, itaconic acid, and maleic anhydride.

195. A method as recited in claim 182 wherein one unsaturated monomer is acrylic acid and the other unsaturated monomer is selected from the group consisting of maleic acid, itaconic acid, and maleic anhydride.

196. A method as recited in claim 183 wherein said unsaturated monomers are selected from the group consisting of acrylic acid, maleic acid, maleic anhydride, methacrylic acid, itaconic acid, crotonic acid, vinyl acetic acid, fumaric acid, citraconic acid, mesaconic acid, acrylonitrile, methacrylonitrile, alpha-methylene glutaric acid, cyclohexenedicarboxylic acid, cis-1,2,3,6-tetrahydrophthalic anhydride, 3,6-epoxy-1,2,3,6-tetrahydrophthalic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, bicyclo[2.2.2]-5-octene-2,3-dicarboxylic anhydride, 3-methyl-1,2,6-tetrahydrophthalic anhydride, and 2-methyl-1,3,6-tetrahydrophthalic anhydride.

197. A method as recited in claim 183 wherein acrylic acid is the sole unsaturated monomer.

198. A method as recited in claim 183 wherein the sole unsaturated monomer is selected from the group consisting of maleic acid, itaconic acid, and maleic anhydride.

199. A method as recited in claim 183 wherein one unsaturated monomer is acrylic acid and the other unsaturated monomer is selected from the group consisting of maleic acid, itaconic acid, and maleic anhydride.

200. A composition as recited in claim 131 wherein said phosphorus-containing carboxylate is a co-oligomer or copolymer obtained from the polymerization of two or more unsaturated monomers in the presence of a phosphorus containing compound, a major proportion of residues (more than 50% by weight) of the phosphorus-containing carboxylate being derived from carboxyl monomers which contain one or more carboxyl groups or which contain one or more groups that have been transformed after polymerization into carboxyl groups, the remaining residues being obtained from non-carboxyl monomers, and in which the resulting phosphorus-contain-ing carboxylate contains phosphorus incorporations that are predominantly or exclusively present as end-type phosphino species or the water soluble salts thereof.

201. A method as recited in claim 200 wherein the non-carboxyl monomers are selected from the group consisting of 2-acrylamido-2-methylpropanesulfonic, 2-hydroxy-3-(2-propenyloxy)propanesulfonic acid, 2-methyl-2-propene-1-sulfonic acid, allylsulfonic acid, allyloxybenzenesulfonic acid, styrenesulfonic acid, vinylsulfonic acid, allylphosphonic acid, vinylphosphonic acid, isopropenylphosphonic acid, phosphoethyl methacrylate, hydroxyalkyl and C1-C4 alkyl esters of acrylic or methacrylic acid, acrylamides, alkyl substituted acrylamides, allyl alcohol, 2-vinyl pyridine, 4-vinyl pyridine, N-vinylpyrrolidone, N-vinylformamide, N-vinylimidazole, vinyl acetate, hydrolyzed vinyl acetate, and styrene.

202. A method as recited in claim 200 wherein said carboxyl monomers are selected from the group consisting of acrylic acid, maleic acid, maleic anhydride, methacrylic acid, itaconic acid, crotonic acid, vinyl acetic acid, fumaric acid, citraconic acid, mesaconic acid, acrylonitrile, methacrylonitrile, alpha-methylene glutaric acid, cyclohexenedicarboxylic acid, cis-1,2,3,6-tetrahydrophthalic anhydride, 3,6-epoxy-1,2,3,6-tetrahydrophthalic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, bicyclo[2.2.2]-5-octene-2,3-dicarboxylic anhydride, 3-methyl-1,2,6-tetrahydrophthalic anhydride, and 2-methyl-1,3,6-tetrahydrophthalic anhydride.

203. A method as recited in claim 202 wherein the carboxyl monomer is selected from the group consisting of acrylic acid, maleic acid, itaconic acid, and maleic anhydride.

204. A composition as recited in claim 131 wherein said phosphorus-containing carboxylate is a co-oligomer or copolymer obtained from the polymerization of two or more unsaturated monomers in the presence of a phosphorus containing compound, a major proportion of residues (more than 50% by weight) of the phosphorus-containing carboxylate being derived from carboxyl monomers which contain one or more carboxyl groups or which contain one or more groups that have been transformed after polymerization into carboxyl groups, the remaining residues being obtained from non-carboxyl monomers, and in which the resulting phosphorus-containing carboxylate contains phosphorus incorporations that are predominantly or exclusively present as phosphono species or the water soluble salts thereof.

205. A method as recited in claim 204 wherein the non-carboxyl monomers are chosen from the group consisting of 2-acrylamido-2-methylpropanesulfonic, 2-hydroxy-3-(2-propenyloxyl propanesulfonic acid, 2-methyl-2-propene-1-sulfonic acid, allylsulfonic acid, allyloxybenzenesulfonic acid, styrenesulfonic acid, vinylsulfonic acid, allylphosphonic acid, vinylphosphonic acid, isopropenylphosphonic acid, phosphoethyl methacrylate, hydroxyalkyl and C1-C4 alkyl esters of acrylic or methacrylic acid, acrylamides, alkyl substituted acrylamides, allyl alcohol, 2-vinyl pyridine, 4-vinyl pyridine, N-vinylpyrrolidone, N-vinylformamide, N-vinylimidazole, vinyl acetate, hydrolyzed vinyl acetate, and styrene.

206. A method as recited in claim 204 wherein said carboxyl monomers are chosen from the group consisting of acrylic acid, maleic acid, maleic anhydride, methacrylic acid, itaconic acid, crotonic acid, vinyl acetic acid, fumaric acid, citraconic acid, mesaconic acid, acrylonitrile, methacrylonitrile, alpha-methylene glutaric acid, cyclohexenedicarboxylic acid, cis-1,2,3,6-tetrahydrophthalic anhydride, 3,6-epoxy-1,2,3,6-tetrahydrophthalic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, bicyclo[2.2.2]-5-octene-2,3-dicarboxylic anhydride, 3-methyl-1,2,6-tetrahydrophthalic anhydride, and 2-methyl-1,3,6-tetrahydrophthalic anhydride.

207. A method as recited in claim 206 wherein the carboxyl monomer is chosen from the group consisting of acrylic acid, maleic acid, itaconic acid, and maleic anhydride.

208. A composition as recited in claim 131 wherein said phosphorus-containing carboxylate is a co-oligomer or copolymer obtained from the polymerization of two or more unsaturated monomers in the presence of a phosphorus containing compound, a major proportion of residues (more than 50% by weight) of the phosphorus-containing carboxylate being derived from carboxyl monomers which contain one or more carboxyl groups or which contain one or more groups that have been transformed after polymerization into carboxyl groups, the remaining residues being obtained from non-carboxyl monomers, and in which the resulting phosphorus-containing carboxylate contains phosphorus incorporations that are predominantly or exclusively present as dialkylphosphino species or the water soluble salts thereof.
209. A method as recited in claim 208 wherein the non-carboxyl monomers are selected from the group consisting of 2-acrylamido-2-methylpropanesulfonic, 2-hydroxy-3-(2-propenyloxy)propanesulfonic acid, 2-methyl-2-propene-1-sulfonic acid, allylsulfonic acid, allyloxybenzenesulfonic acid, styrenesulfonic acid, vinylsulfonic acid, allylphosphonic acid, vinylphosphonic acid, isopropenylphosphonic acid, phosphoethyl methacrylate, hydroxyalkyl and C1-C4 alkyl esters of acrylic or methacrylic acid, acrylamides, alkyl substituted acrylamides, allyl alcohol, 2-vinyl pyridine, 4-vinyl pyridine, N-vinylpyrrolidone, N-vinylformamide, N-vinylimidazole, vinyl acetate, hydrolyzed vinyl acetate, and styrene.
210. A method as recited in claim 208 wherein said carboxyl monomers are selected from the group consisting of acrylic acid, maleic acid, maleic anhydride, methacrylic acid, itaconic acid, crotonic acid, vinyl acetic acid, fumaric acid, citraconic acid, mesaconic acid, acrylonitrile, methacrylonitrile, alpha-methylene glutaric acid, cyclohexenedicarboxylic acid, cis-1,2,3,6-tetrahydrophthalic anhydride, 3,6-epoxy-1,2,3,6-tetrahydrophthalic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, bicyclo[2.2.2]-5-octene-2,3-dicarboxylic anhydride, 3-methyl-1,2,6-tetrahydrophthalic anhydride, and 2-methyl-1,3,6-tetrahydrophthalic anhydride.
211. A method as recited in claim 210 wherein the carboxyl monomer is selected from the group consisting of acrylic acid, maleic acid, itaconic acid, and maleic anhydride.
212. A composition as recited in claim 131 wherein said phosphorus-containing carboxylate is a co-oligomer or copolymer obtained from the polymerization of two or more unsaturated monomers in the presence of a phosphorus containing compound, a major proportion of residues (more than 50% by weight) of the phosphorus-containing carboxylate being derived from carboxyl monomers which contain one or more carboxyl groups or which contain one or more groups that have been transformed after polymerization into carboxyl groups, the remaining residues being obtained from non-carboxyl monomers, and in which the resulting phosphorus-containing carboxylate contains phosphorus incorporations that are present as a mixture of phosphono, end-type phosphino, and dialkylphosphino species or the water soluble salts thereof.

213. A method as recited in claim 212 wherein the non-carboxyl monomers are selected from the group consisting of 2-acrylamido-2-methylpropanesulfonic, 2-hydroxy-3-(2-propenyloxy)propanesulfonic acid, 2-methyl-2-propene-1-sulfonic acid, allylsulfonic acid, allyloxybenzenesulfonic acid, styrenesulfonic acid, vinylsulfonic acid, allylphosphonic acid, vinylphosphonic acid, isopropenylphosphonic acid, phosphoethyl methacrylate, hydroxyalkyl esters of acrylic or methacrylic acid, C1-C4 alkyl esters of acrylic or methacrylic acid, acrylamides, alkyl substituted acrylamides, allyl alcohol, 2-vinyl pyridine, 4-vinyl pyridine, N-vinylpyrrolidone, N-vinylformamide, N-vinylimidazole, vinyl acetate, hydrolyzed vinyl acetate, and styrene.

214. A method as recited in claim 212 wherein said carboxyl monomers are chosen from the group consisting of acrylic acid, maleic acid, maleic anhydride, methacrylic acid, itaconic acid, crotonic acid, vinyl acetic acid, fumaric acid, citraconic acid, mesaconic acid, acrylonitrile, methacrylonitrile,'alpha-methylene glutaric acid, cyclohexenedicarboxylic acid, cis-1,2,3,6-tetrahydrophthalic anhydride, 3,6-epoxy-1,2,3,6-tetrahydrophthalic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, bicyclo[2.2.2]-5-octene-2,3-dicarboxylic anhydride, 3-methyl-1,2,6-tetrahydrophthalic anhydride, and 2-methyl-1,3,6-tetrahydrophthalic anhydride.

215. A method as recited in claim 214 wherein the carboxyl monomer is selected from the group consisting of acrylic acid, maleic acid, itaconic acid, and maleic anhydride.

216. A method as recited in claim 131 wherein said phosphorus-containing carboxylate is a phosphonic polymer having the generalized formula wherein X J is H, an alkali metal atom, an alkaline earth metal atom, or an ammonium or amine residue; and R J1 is a copolymer residue comprising two different residues wherein z is an integer ranging from 2 to 100, and wherein, in the first residue, R J2 is -COOH, and in the second residue, R J2 is -CONHC(CH3)2CH2SO3X J, wherein X J is as hereinbefore defined.

217. A method as recited in claim 131 wherein the aqueous system treatment material is a composition of up to 50% by weight of a phosphonosuccinic acid, based on the weight of the composition, a phosphonated dimer of alkali metal maleate, not more than a minor proportion by weight, based on the weight of the dimer, of higher phosphonated oligomers of maleate; and from 0.5 to 5% by weight of the composition of an alkali metal phosphate.

218. A method as recited in claim 131 wherein the long chain fatty acid derivative of a sarcosine is chosen to be N-Lauroylsarcosine or the water soluble salts thereof.

219. A method as recited in claim 130 wherein the composition includes water.

220. A method as recited in claim 131 wherein the composition additionally includes water.

221. A method as recited in claim 131 wherein said composition additionally contains at least one additive chosen from the group consisting of:
i. one or more dispersants ii. one or more copper corrosion inhibitors iii. one or more aluminum corrosion inhibitors iv. one or more water-soluble metal salts of metals chosen from the group zinc, manganese, aluminum, tin, nickel, yttrium, and the rare earth metals v. one or more water-soluble organic metal chelates of metals ions chosen from the group zinc, manganese, aluminum, tin, nickel, yttrium, and the rare earth metals, where the organic chelant is chosen to impart a desired level of water solubility of the metal ion vi. one or more scale control agents vii. one or more sequestering agents viii. one or more anti-foaming agents ix. one or more oxidizing biocides x. one or more non-oxidizing biocides xi. one or more water-soluble alcohols capable of lowering the freezing point of an aqueous system xii. one or more ionic freezing point depressants xiii. one or more pH adjusting agents xiv. one or more inert tracers xv. one or more active tracers xvi. one or more water insoluble organic lubricants xvii. one or more water soluble lubricants xviii. one or more surfactants xix. one or more calcium hardness adjusting agents, and xx. one or more coloring agents.

222. A method as recited in claim 221 wherein the composition additionally includes water.

223. A method as recited in claim 221 where the dispersant is a water-soluble sulfonated polymer or copolymer obtained from the polymerization of one or more ethylenically unsaturated monomers.

224. A method as recited in claim 223 where the water-soluble sulfonated copolymer is about a 3:1 weight ratio copolymer of acrylic acid and allyl hydroxy propyl sulfonate ether or the water soluble salts thereof.

225. A method as recited in claim 221 where the dispersant is a copolymer of diiosbutylene and maleic anhydride with molecular weight<10,000 or its water soluble salts.

226. A method as recited in claim 221 where the copper corrosion inhibitor is tolyltriazole.

227. A method as recited in claim 221 where the copper corrosion inhibitor is a mixed maleic composition including at least 65% of the 5-methylbenzotriazole isomer by weight.

228. A method as recited in claim 221 where the copper corrosion inhibitor is benzotriazole.

229. A method as recited in claim 221 where the copper corrosion inhibitor is mercaptobenzothiazole.

230. A method as recited in claim 221 where the copper corrosion inhibitor is an akyl or alkoxy substituted benzotriazole wherein the substitution occurs on the 4 or 5 position of the benzene ring.

231. A method as recited in claim 230 wherein the substituent is chosen from the group consisting of n-butyl and hexyloxy.

232. A method as recited in claim 221 where the copper corrosion inhibitor is phenyl-5-mercaptotetrazole.

233. A method as recited in claim 221 where the copper corrosion inhibitor is a halogen-tolerant azole.

234. A method as recited in claim 233 where the halogen-tolerant azole is chloro-tolyltriazole.

235. A method as recited in claim 221 where the aluminum corrosion inhibitor is a water-soluble nitrate salt.

236. A method as recited in claim 235 where the water-soluble nitrate salt is sodium nitrate.

237. A method as recited in claim 221 where the water-soluble metal salt is obtained from zinc.

238. A method as recited in claim 237 where the zinc salt is the sulfate, chloride, acetate, or nitrate salt.

239. A method as recited in claim 221 where the metal salt is obtained from manganese in the +2 oxidation state.

240. A method as recited in claim 239 where the manganese salt state is the sulfate, chloride, acetate, or nitrate salt.

241. A method as recited in claim 221 where the metal salt is obtained from lanthanum or a mixture of rare earth metals containing lanthanum.

242. A method as recited in claim 241 where the lanthanum salt or mixture of rare earth metal salts containing lanthanum are independently selected from the group consisting of the sulfate, chloride, acetate, and nitrate salts.

243. A method as recited in claim 221 where the sequestering agent is selected from the group consisting of ethylenediaminetetra(acetic acid), nitrolotriacetic acid, N,N-di(2-hydroxyethyl)glycine and the water soluble salts thereof.

244. A method as recited in claim 131 wherein the alkali metal silicate is sodium metasilicate.

245. A method as recited in claim 221 where the anti-foaming agent is selected from the group consisting of silicones, polydimethylsiloxanes, distearylsebacamides, distearyladipamide, fatty alcohols, and ethylene oxide condensates of fatty alcohols.

246. A method as recited in claim 221 where the oxidizing biocide is selected from the group consisting of chorine, hypochlorite, bromine, hypobromite, chlorine donor compounds, bromine donor compounds, peracetic acid, inorganic peroxides and peroxide generators, chlorine dioxide, ozone and mixtures thereof.

247. A method as recited in claim 221 where the non-oxidizing biocide is selected from the group consisting of amines, quaternary ammonium compounds, 2-bromo-2-nitropropane-1,3-diol, .beta.-bromonitrostyrene, dodecylguamctme hydrochlonde, 2,2-dibromo-3-nitrilopropionamide, gluteraldhyde, chlorophenols, sulphones, methylene bis thiocyanates, methylene bis carbamates, isothiazolones, brominated propionamides, triazines, phosphonium compounds, organometallic compounds and mixtures thereof.

248. A method as recited in claim 221 where the non-oxidizing biocide is a mixture of (a) 2-bromo-2-nitropropane-1,3-diol (BNPD) and (b) a mixture of about 75% 5-chloro-2-methyl-4-isothiazolin-3-one and about 25% 2-methyl-4-isothiazolin-3-one, the weight ratio said BNPD (a) to said mixture (b) being about 16:1 to about 1:1.

249. A method as recited in claim 221 where the water-soluble alcohol freezing point depressant is selected from the group consisting of ethylene glycol, propylene glycol, ethanol, glycerol, isopropanol, and methanol, or mixtures thereof.

250. A method as recited in claim 221 where the ionic freezing point depressant is selected from the group consisting of calcium chloride, sodium chloride, lithium bromide, and lithium chloride.

251. A method as recited in claim 221 where the pH adjusting agent is selected from the group consisting of sodium hydroxide, potassium hydroxide, lithium hydroxide, hydrochloric acid, sulfuric acid, nitric-acid, carbon dioxide, ammonia, organic acids such as oxalic acid, alkali metal carbonates, and alkali metal bicarbonates.

252. A method as recited in claim 221 where the inert tracer is selected from the group consisting of soluble lithium salts, transition metals, and fluorescent materials.

253. A method as recited in claim 221 where the active tracer is selected from the group consisting of fluorescently tagged polymers, polymers containing a photo-inert, latently detectable moiety, water soluble molybdate salts, and azole-based copper corrosion inhibitors.

254. A method as recited in claim 221 where the water insoluble organic lubricant is selected from the group consisting of naturally occuring oils and synthetic oils.

255. A method as recited in claim 221 where the surfactant is selected from the group consisting of anionic, cationic, amphoteric, and nonionic surfactants.

256. A method as recited in claim 221 where the calcium hardness adjusting agent is selected from the group consisting of the bicarbonate, carbonate, chloride, sulfate, and acetate salts of calcium, calcium hydroxide and calcium oxide.

257. A method as recited in claim 221 where the coloring agent is a water soluble dye.

258. A method as recited in claim 131 wherein said monofluorophosphate is sodium monofluorophosphate.
259. A method as recited in claim 155 wherein the weight ratio of ortho-phosphate species to pyrophosphate species is in the range of about 20:1 to about 1:20, when both species are expressed as PO4 -3.
260. A method according to claim 130 where the aqueous system is a cooling water system.
261. A method according to claim 260 where the cooling system is an open, evaporative cooling water system.
262. A method according to claim 260 where the cooling system is a once-through system.
263. A method according to claim 260 where the cooling system is closed loop cooling system.
264. A method according to claim 263 where the closed loop cooling system is the cooling system of an internal combustion engine.
265. A method according to claim 263 where the closed loop cooling system is a brine-based system which captains at least one additive selected from the group consisting of calcium chloride, lithium chloride, lithium bromide, and sodium chloride.
266. A method according to claim 263 where the closed loop cooling system is a system which contains at least one additive chosen from the group consisting of ethylene glycol, propylene glycol, ethanol, glycerol, isopropanol, and methanol.
267. A method according to claim 130 where the aqueous system is a hot water heating system.
268. A method according to claim 130 where the aqueous system is selected from the group consisting of pulping and papermaking systems, food and beverage systems, boiler systems, refinery systems, petrochemical processing systems, mining systems, and metal machining systems which utilize aqueous metal working fluids.
270. A method according to claim 130 where the aqueous system contains a fluid that is at least 5 percent by weight water.
271. A method according to claim 130 where the aqueous system contains a fluid that is at least 50 percent by weight water.
272. A method according to claim 130 where the aqueous system contains a fluid that is at least 90 percent by weight water.

273. A method according to claim 130 where the aqueous system contains dissolved oxygen.
274. A method according to claim 130 where the aqueous system is substantially or completely free of dissolved oxygen.
275. A method according to claim 130 where the aqueous system contains at least one dissolved gas chosen from group consisting of oxygen, carbon dioxide, hydrogen sulfide, and ammonia.
276. A method according to claim 130 where the aqueous system contains ferrous metal.
277. A method according to claim 276 where the ferrous metal is at least one metal selected from the group of cast iron, mild steel, low alloy steel, and stainless steel.
278. A method according to claim 130 where the aqueous system contains non-ferrous metal.
279. A method according to claim 278 where the non-ferrous metal is at least one metal selected from the group consisting of aluminum, copper, and the copper-based alloys.
280. A method according to claim 130 where the aqueous system contains both ferrous and non-ferrous metals.
281. A method according to claim 130 where the components are introduced into the system at an effective concentration by a slug feed.
282. A method according to claim 130 where the components are fed into the system using a combination of intermittent and continuous methods.
283. A method according to claim 130 where some of the components are fed into the system on a continuous basis and the remaining components are fed on an intermittent basis.
284. A method according to claim 130 where components are introduced into the aqueous system at an effective concentration by a controlled release delivery system.
285. A method according to claim 130 where the combination of components is introduced into said aqueous system at a total concentration of about 0.5 to about 10,000 parts per million by weight.
286. A method according to claim 130 where the combination of components is introduced into said aqueous system at a total concentration of about 10 to about 1,000 parts per million by weight.

287. A method according to claim 130 where the weight ratio of component b) to component a) is from about 100:1 to about 1:20.
288. A method according to claim 130 where the weight ratio of component b) to component a) is from about 20:1 to about 1:1.
289. A method according to claim 130 where the pH of said aqueous system is from about 6 to about 10.
290. A method of controlling corrosion, deposition, and scale in an aqueous system having a pH of about 6 or greater which comprises introducing into said system a combination of:
(a) a tetrazolium compound of the formula:

wherein R1, R2 and R3 are selected from the group consisting of lower alkyl, branched lower alkyl, aryl, substituted aryl, alkylaryl, substituted alkylaryl and heterocyclic substituted aryl, with the proviso that neither R1, R2, or R3 contain more than 14 carbon atoms;
and n is 1 or 2, such tetrazolium compound optionally having associated water soluble ionic species if needed to obtain a neutral charge, and (b) at least one other aqueous system treatment material chosen so that the material does not substantially reduce the tetrazolium compound, and additionally selected so that at least one of these treatments is effective in inhibiting scale and/or deposition.
291. A method for controlling corrosion of stainless steel in contact with an aqueous system which comprises introducing into said system at least one tetrazolium compound of the formula:

wherein R1, R2 and R3 are selected from the group consisting of lower alkyl, branched lower alkyl, aryl, substituted aryl, alkylaryl, substituted alkylaryl and heterocyclic substituted aryl, with the proviso that neither R1, R2, or R3 contain more than 14 carbon atoms;
and n is 1 or 2, such tetrazolium compound optionally having associated water soluble ionic species if needed to obtain a neutral charge.
292. The method as recited in claim 300, wherein the aqueous system includes at least one other aqueous system treatment material chosen so that the material does not substantially reduce the tetrazolium compound.
293. The method as recited in claim 130 or 291 wherein the aqueous system contains dissolved oxygen.
294. The method as recited in claim 130 or 291 wherein the at least one tetrazolium is added to the aqueous system at active treatment levels ranging from about 0.1 to about 50 parts per million.
295. The method as recited in claim 294 wherein the at least one tetrazolium compound is added to the aqueous system at active treatment levels ranging from about 1 to about 25 parts per million.
296. The method as recited in claim 130 or 291 wherein the at least one tetrazolium compound is added to the aqueous system at active treatment levels ranging from about 0.1 to about 50 parts per million and the aqueous system contains oxygen.
297. The method as recited in claim 296 wherein the at least one tetrazolium compound is added to the aqueous system at active treatment levels ranging from about 1 to about 25 parts per million.