CA1325757C - Method for inhibiting oxidation of ferrous metals and composition for cleaning ferrous metals - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
Glycosides and polyglycosides are described having the formula R(OG)x wherein R is an aliphatic hydrocarbon radical having from 1 to 25 carbon atoms or is a radical with the formula R1(OR2)n which does not have more than 75 carbon atoms and wherein n = 0 to 24 and R1 and R2 are aliphatic hydrocarbon radicals, G is the residue of a saccharide moiety selected from the group consisting of fructose, glucose, mannose, galactose, talose, gulose, allose, altrose, idose, arabinose, xylose, lyxose, ribose or alkoxylated derivatives thereof and x is 1 to 30 which glycosides and polyglycosides inhibit oxidation and acid attack of ferrous metals.

Description

13 2 5 7 ~ 7 PCT CASE ~000840 ARSHAD H . MALI K

METHOD FOR INHIBITING OXIDATION OF FERROLlS METALS
AND COMPOSITION FOR CLEANiNG FERROUS METALS
~_,", . . . .
This application relates to the inhibition of oxidation of ferrous metals. More particularly, this invention relates to the use of alkyl glycosides, alkyl polyglycosides lAPGs) or mixtures thereof to inhibit the oxidation of ferrous metals and acid attack of ferrous metals.
Ferrous metals when soiied frequently are the subject of cleaning with cieaning compositions. Acid cleaning compositions often are used for the removal of 0 soil such as iron oxides in a process known as pickling.
More broadly, however, acid is used for the removal of mill scale (hot-rolied scale) developed during hot forming of metal; scale developed during welding; scale developed during heat treating; superficial oxide which interferes with painting, porcelain enameling, tinning, galvanizing, or electroplating; rust and corrosion products; proteinous deposits; hard water scale; and products of reaction of hard water with soil, especially protein. Acids commonly used for cleaning ferrous metals include, but are not limited to, sulfuric acid, hydrochloric acid, phosphoric acid, nitric acid, hydrofluoric acid and organic acids such as oxalic acid, trichloracetic acid, citric acid, formic acid and acetic acid.
Aci~ cleaning action is enhan-~ed by the use of surfactants especially when a soil such as an oxide is combined with another soil such as oil. Hence, surfactants form an important part of cleaning compositions for the removal of soil from ferrous metals 30 by acid cleaners. Surfactants have the property of concentrating at the surface to be cleaned ~o facilitate cleaning. Further, surfactants facilitate cleaning in ~' ~ ., ` ' , ` .' ' ;

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various other ways which include, but are not limited to, the neutralization of forces which attract soil to the surface to be cleaned and the retention of soil in suspension after its removal to prevent its redeposition 5 on the cleaned surface.
I~horeover, with acid cleaning it is often desirable to have minimal acid attack on the base metal.
Excessive reaction with the metal consumes acid, creates fumes, enhances hydrogen embrittlement, produces smut, 10 and may remove enough metal to affect toierances.
After cleaning a moist clean ferrous metal surface, such as steel, with a mildly acidic residue rerusts very rapidly. Rerusting can be minimized by rapid dry-off and by maintaining the part submerged in 15 cool water prior to a rapid dry-off. If the water is alkaline, oxidation may ~e inhibited; soda ash or lime is often used in the final rinse to prevent rusting during handling. Sodium nitrite solutions of from 0.1 to 10~
concentration, depending on the time of storage, are 20 often used as a final rinse ~and can be quite effective) for those cases where the parts should not be covered with an oily rust preventive. Sodium nitrite, however, leaves a surface deposit which sometimes is considered undesirable in metal working~ Moreover, b~cause the 25 salt tends to break up ~mulsions it causes problems in the formulation of metal cleaners.
As used throughout this application, oxidation means the alteration of a ferrous metal by the formation of oxides wS~ich include but are not limited to rust and 30 mill scale. As used throughout this application, acid attack means the reaction of an acid with a ~errous metal. Ferrous me$al means iron or an alloy of iron - . .: . ~ ............. . ,.
- . - . , ,, .
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- :; . . . : . .

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containing more iron than any other metal, the most common iron alloy being steel.
It is an object of this invention to provide a method for the inhibition of oxidation of ferrous metals.
l t is another object of this invention to provide an oxidation inhibitor for ferrous metals which is stable in an acid medium.
It is still another object of this invention to provide a method for the moderation of acid attack on~
ferrous metais.
It is yet another object of this invention to provide a surfactant, oxidation inhibitor and additive for acid cleaning compositions for ferrous metals.
These and other objects of the invention will become more apparent with reference to the fol lowing detai led descri ption .
According ~o ~he invention glycosides having the formula R~OG)X ( I) 20 wherein R is an al iphatic hydrocarbon radical having from 1 to 25 carbon atoms or is a radical having the formula R1 ~OR2~n which does not have more than 25 carbon atoms and wherein n - 0 to 24 and R1 and R2 ar~ aliphatic hydrocarbon radicals, G is the residue of a saccharide moiety select~d from the group consisting of fructose, glucose, mannose, gaiactose, talose, g ulose, allose, altrose, idose, arabinose, xylose, Iyxose, ribose, alkoxylated derivatives of any of the -~32~ ~7 foregoing saccharide materials, or mixtures thereof, and x is 1 to 30 inhibit oxidation of ferrous metals, inhibit acid attack thereon and are stable in an acid rnedium. Preferably 5 the glycosides used in the invention are alkyl glucosides (G is glucose). The degree of polymerization of the polyglycosid2s varies and is in the range of about 1 to 3~ lx = 1 to 30). When the glycosides and polyglycosides are made or purchased they most often 10 are mixtures comprising lecules of varying degrees of polymerization. Polyglycosic~es in these mixtures have a degree of polymerization as high as 30, most of the polygiycosides have a degree of polymerization of 10 or less and most of the latter group has a degree of 15 polymerization of 1 to 4. Because the glycosides are often found as mixtures x may be expressed as an average degree of polymerization which includes fractional numbers. Recognizing that th~ glycosides used according to the inv~ntion are mixtures with 20 varying degrees olF polymerization, preferably the degree of polymerization of the polyglycosides is from about 1 to about 10 and most preferably is in the range of from about 1 to about 4. R is preferably at the Cl position of the glycoside and is preferably an alkyl group which 25 is straight chained or branched having 1~ ~ 13 carbon atom and most pre~2rably 9 to 13 carbon atoms.
The glycosides used in the invention inhibit oxidation within a pH range where oxidation occurs which includes a pH of 7 and below and up to a pH of 30 about 9. They are stable in an acid medium and inhibit oxidation without leaving undesirable deposits which heretofore had been a problem. Moreover, the glycosides used in the invention inhibit acid attack of .. , . . , ~ ~

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metallic iron and alloys thereof. According to the method of the invention, solutions having less than two percent by weight on a dry basis of inorganic s~lts and comprising, on a total weight ~asis, from about 0.1 to about 50 percent by weight of the glycosides of the invention, preferably from about 1 to about 20 percent by weight and most preferably about 1 to about 10 percent by weight are applied to the ferrous rnetal to inhibit oxidation and acid attack thereof. The solutions may be made with any solvent which sol~rates the glycosides and which are compatible with ferrous metal such solvents including, but not limited to, water, glycol ether solvents including ethylene glycol monoethyl ether which is available as Cellosolve solvent, tetrahydrofurfuryl alcohol, butyl alcohol and mixtures thereof. Application of the soiution may be any way 9f contacting the solution with the surface of the metal including, but not limited to, immersion, ~praying or dipping. Thickeners, as are known, such 25 xanthan gum, polyacrylics or colloidal magnesium aluminum silicates which are available as Veegun~ may be included in the solutions of the glycosides as required. After application, the glycoside solution i5 permitted to evapo~ate or is dried from the surface of the metal.
The method of the invention is particulariy pertinent to the acid d~aning of ~errous metals with acids such as sulfuric, hydrochloric, phosphoric, nitric, hydrofluoric and organic acids such as oxalic, trichloroacetic, forsnic, citric or acetic acid, when the ~a~ter acids are combined with aqueous salutions of the glycosides of the invention to provide ferrous metal cleaning compositions. The glycosides not only act as a surfactant to assist cleaning, but also inhibit oxidation * Trade Mark ~ ~32~7~i~

of the cleaned surface and acid attack on the base metal.
Hence the cleaning compositions which include the glycosides not only clean the surface of the metal without undesirable acid attack of the base metal, but 5 also ha~e the unexpected property of inhibiting oxidation on leaned surface of the metal. It has been found ~hat -- - glycosides of formula I have excellent stabi-lity -~nder highly acid conditions. The glycosides which are excellent surfactant materials provide sufflcient foaming in hard surface cleaners so that the acid component of the cornposition does not merely run off of the surface being cleaned. The aqueous acidic cleaning compositions, on a total weight basis, have from 0.1 to about 50 percent by weight of the glycosides described herein, preferably about 1 to about 20 percent by weight and most preferably about 1 to about 10 percent by volume. The aquaous cleaning compositions should pre~erably have a pH in the range of about 0.1 to about 4.3 and less than about two percent by weight, on a total weight basis, on a dry basis of inorganic salts for the cleaning composjtion to ~xhibit oxidation inhibition.
Other ingredients such as thickeners and organic soh/ents as previously described may be optionally added he cleaning composition. The acids ~suitable for use irl the present inYention inslude relatively strong acids : such as sulfuric, hydr~>chloric, gluconie, nitric, sul~mic, oxalic, phosphorie, phosphorous or any other strong acid. Such ~cids may conveniently have a dissociation constant Kl at 25C of equal to or greater than 2.5 x 10 4; preferably equal to or greater than 1 x 10 4; mor~ preferably equal to or greater than 5 x 10 3;
n~st preferably 1 x 10 3 or greaterO Such strong acids, when employed at 0.1N in distilled water at 25C, will ~ i32~7~7 typically give a pH of 1~8 or less preferably 1.6 or less. The cleaning compositiDns of the invention may be applied to the metal surface to be cleaned by dipping, spraying or immersion with contact times being a 5 ~unction of the application method, temperature and pH
of the composition.
The various glycoside and polyglycoside cDmpounds and processes for making them are disclosed in U.S. Patent Nos. 2,97~,134; 3,219,6~6; 3,598,86~;
3,707,535 3,772,269; 3,839,318; 3,974,138; and 4,2~3,129. Alkoxylated glycosides, such as those disclosed in lJ.S. Patent 3,~40,~98, are also useful herein. Moreover, a mixture of alkyl glucosides and alkyl polyglycosides which may be used in the 1~ the method of the invention are commercially available as Triton* BG-10 from the Rohm and Haas Company.

Where an asid is present in the solution used in the method Df the invention it is typically employed at ~rom about ~% to about 7G96 ~y weight of the ac~ual acid species, e. g " 37% hydrochloric ~cid is expressed as a 100~ HCI basis. Thus the amount of acid utilized is conY~niently from about 6% t~ ~bout 50~6; and most pre~erably from about 8% to a~out 45~6 by weight.
The acid and the glycoside may be mixed to the desired proporti~ns in any conYenient manner. It is desired however that when mixing the glycoside and the acid, a minimal amount of agitation be employed as this tends to cause the glycoside to ~oam which is not 3D particularly desirable during preparation of the compositions of interest. As the glycoside and the acid are b~th compatible liquid materials, it is possible to * Trade Mark - .
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form a simple mixture or upon careful agitation to obtain a true solution of the giycoside and acid.
As most of the acids employed herein are obtained in their concentrated aqueous form. it is a S further desirable variat)le herein that the solutions used in the method of the invention be aqueous with the amount of water employed typically being from about 10%
to about 95%; and preferably from about 15% to about 7~%.
Other materials which may be incorporated within the treatment solutions and/or acidic cleaning compositions hereof include an anionic surfactant such as an alkylsul~ate, paraffin sulfate, paraffin sulfonate, olefin sulfonate, alkylether sulfate, or an alkylbenzene 15 sulfonate. These anionic surfactants are typicaily found in the form of their sodium, potassium or ammonium salt, however, it is noted herein that due to the high de~ree of acidity in the present compositions the anionic surfactants will typically be in their acid form to a 20 substantial degree notwithstandling the cationic salt species employed.
Amines may be included in the acidic cieaning compositions herein at from 0% to 5096 by weigh$ to ~urther inhibit acid et~hing of the metal surface.
25 Preferably, the amines will be nonaromatie materials.
The amines should be used at less than a 10:1 ratio to the glysoside. Quaternary comp~unds may be included, if desired.
Additional ingreclients whioh may be employed 30 in the treatment solutions and acidic cleaning compositions hereof include materials such as detergent builders and abrasive materials. Certain abrasive materials, such as caicium carbonate, would tend to ~ .;, .
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g decompose and liberate carbon dioxide. Thus it is more preferred that a material such as a silica be employed as the abrasive to avoid having the abrasive material decompose upon storage. The amount of detergent 5 builder or abrasive which may be included in the aciclic cleaning compositions is typically from about 296 to about 40%; preferably from about 3% to about 30% by weight.
Suitable builders include the phosphates, nitrilotriacetic acid ~NTA~, aluminosilicates and the builders disclosed 1 0 EP-A-150930.

.

1 3 2 5 7 ~ 7 EXAMPLE I
The oxidation inhibition capabilities o~ the glycosides o~ the invention were evaluated by the fol lowing test. Water with 100 ppm hardness is 5 prepared. The material to be tested for its rust inhibition capabilities is added. Three grams of degreased cast iron chips of 15 to 40 mesh are piaced on #1 filter paper having an area of one square inch and 3 ml of the test solution are added to the metal chips 10 which then are dried for 16 hoursO After drying chips and filter paper are evaluated for rust and are rated on a scale from 1 to 10 with 19 indicating no rust. In the test resutts shown in Table I, hard water with no additives and a solution of sodium nitrite were used as 15 controls. Igepa~ C0630, Neodol*25-35, E~iosoft* 1~-62 and Dowfax* 2A1 are known surfactants~ APG* stands for glycoside compounds of the Formula I above.

* Trade Mark .L~

.

13 2 5 7 ~ 7 TABLE I
RUST INHIBITION CAPABILITIES FOR
FERROUS METALS OF AQUEOUS SOLUTIONS
OF GLYCOSIDES, POLYGLYCOSIDE~ AND
OTHER SURFACTANTS
SURFACTANT CONONTRATION
~ Salt OX 1% ~ ~5% ~~ -~0%
on dry basis wel~t %
Water (Control) --- 5.0 NaN02 (Control ) --- 500 9.0 10.0 Methyl 6lucoside C1.0 5.7 5.5 5.5 Ethyl 61 ucosi de <1. 0 5 . 7 5 . 65 . 2 Butyl ~lucoside <1.0 5.0 5.7 7.3 2-Ethyl Hexyl 6lucoside <1.0 4.0 8.0 8.0 APG where x averages 1.5 and G
is derived from glucose and R i s deri ved f rom C to C1 alcohols s81d by ~hell Oil Company under the name Neodol 91. ~1.0 6.3 8.0 8.5 APG where x averages 1.5, 6 is glucose and-R derived from Neodol 91. 4.1 4.8 4.8 4.8 AP6 ~here G i s gl ucose ~
x ~verages about 1.8 to 3 and R is derived fr~n Neodol 91. 11.9 6.0 5.5 4.0 APG where 6 is glucose, x averages about 3 and R is derived from Cl~ ~o C1~
alcoho~ sold ~y Shel l Oi l Company under the name of Neodol 23. <1.0 5.6 5.7 5.7 APG where 6 is glucose, -7 ~ ~

x averages about 3 and R is derived f rom Neodol 23 . 9 . 2 3 . 5 4 . 2 2 . 5 AP6 where 6 is glucose, x averages 3 and R
is derived from Neodol 23. <1.0 6.5 7.2 7.2 APG where G is 61ucose, x averages 3 and R
is derived from Neod~l 23 . 12 . 7 3 . 5 3 . 5 3 . 5 C12 to C1 ethoxy-l ated ~l cohol s sold by Shell Chemical Company under the na~e of Neodol 25 whieh is the reaction product of alcohol with seven moles of ethyl ene oxi de . 4 . 2 3 . 5 1. 0 Nonyl phenol ethoxy-late sold by 6AF
under the name of Igepal wh~ch is the reaction product of 9-1/2 moles of ethylene oxide wi th phenol . 3 . 0 2 . 5 1. 0 Alkyl ether sulfate ~sold by Shell -Chelnioal Colnpany under the name of Neodol 25 3S. 2.0 2.0 1.5 Sodium linear alkyl benzene sulfonat2 which is an anionic surfactant sold by ~tephan Chemical Company under the name of Biosoft ~-62. 2.0 1.~ l.0 - . ... : ~. - -, . ~ .... .

~ ~32~7r7 A branched Cl alkylated ~iphenyl oxide disulfonate some of which is a sodium salt and which is an anionic surfactant sold by The Dow Chemical Company under the trademark Dowfax ~A1. 2.0 1.5 1.0 Higher Number represents better results.
10 ~ No Rust 1 = Yery Heavy Rust :

i 1 3 ~

EXAMPLE l l I
The capabilities of solutions of the glycosides of the invention to inhibit the acid attack of a ferrous metal surface were tested in various acids as indicated 5 below. In each case the glycoside was a glucoside.
The test was conduc~ed by first recording the weight of a piece of galvanized steel (3" x 1/2" x 1/8"), then heating the seeel in the acid ~or six hours and then measuring and recording the weight loss of the steel.
10 The experiment then was repeated using the acid and APG combination. The weight loss with the AP~; acid solution divided by the weight loss with the acid alone yields the percent corrosion inhibition data illustrated in Table l l .

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~ ~32~7~7 EXAMPLE l l I
The following compositions useful in the method of the invention and listed in Table l l l below are prepared by obtaining a glycoside of the average degree 5 of polymerization (DP) and having an alkyl chain length shown as carbon chain. The acids are presen~ed on an active "solids" basis. The stability of the glycosides in the 2cidic medium of the composition is shown by the maintenance of the surface tension after 7 days storage 10 at 49C.
STABILITY OF GLUC:OSIDE IN ACID MEDIUM
Surface tension (25C) ~~ After 7 Days At Carbon 9~ Initial 49C
Chain DPGlucoside ~ AcidIDynes/cm)(Dynes~cm, 1.*91 3.01.0 10% HCI 27.5 23.7 2.91 3.01.0 5% HCI 27.2 25.4 3.**~3 3.0 0.1 ~0~ IICI 27.3 23.5 20 4.23 3.0 1.0 20% HCI 27.3 23.4 5.23 3.0 1.0 20~H254 27.4 25.4 6.23 3 . 0 9. 1 1 ~%1 12SO~ 27 . 4 25 .~
7.23 3.0 1.0 40%H3PO4 27.8 26.7 25 8 23 3.0 0.1 4096H3PO4 29.1 21.0 * 91 is a mixture of nonyl, deeyl and undecyl, i.e. R
derives from the alcoho, mixture sold by Shell Oil Company under the name Neodol 91.

** 23 is ~ mixture of dodecyi and tridecyl, i . e. R
cierives from the alcohol mixture sold by Shell Oil Cornpany under the name Neodol 23.

:
'`I :

, 1 3 2 ~ 7 ~ 7 It ~hould be understood that while certain preferred embodiments of the present invention have been il lustrated and ciescribed, various modifications thereof will become apparent to those skilled in the art.
5 Accordingly, the scope of the present invention should be defined by the ~ppended claims and equival~nts thereof.
Various features of the invention are set forth in the following claims.

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Claims (13)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A method for inhibiting oxidation or acid attack of a ferrous metal comprising:
contacting the surface of the ferrous metal with 3 solution which has less than about two percent by weight inorganic salts and which solution includes, on a total weight basis, from about 0.1 to about 50 percent by weight of a glycoside having the formula R(OG)x wherein R is an aliphatic hydrocarbon radical having from 1 to 25 carbon atoms or is a radical with the formula R1(OR2)n which does not have more than 25 carbon atoms and wherein n = 0 to 24 and R1 and R2 are aliphatic hydrocarbon radicals, G is the residue of a saccharide moiety selected from the group consisting of fructose, glucose, mannose, galactose, talose, gulose, allose, altrose, idose, arabinose, xylose, lyxose, ribose, alkoxylated derivatives of any of the foregoing saccharides, or mixtures thereof, and x is 1 to 30.

2. A method as recited in Claim 1 wherein G
is glucose, the solution is an aqueous solution and R is an aliphatic hydrocarbon radical.

3. A method as recited in Claim 2 wherein the glycoside comprises, on a total weight basis, from about 1 to about 20 percent by weight of the solution.

4. A method as recited in Claim 2 wherein the glycoside comprises from about 1 to about 10 percent by volume of the solution.

5. A method as recited in any of Claims 2, 3 or 4 wherein R is an alkyl group which is a straight chain or branched having 4 to 13 carbon atoms and x =
1 to 10.

6. A method as recited in any of Claims 2, 3 or 4 wherein R is an alkyl group which is a straight chain or branched having 9 to 13 carbon atoms and x =
1 to 4.

7. A method as recited in any of Claims 2, 3 or 4 wherein said method is for inhibiting oxidation.

8. A method s recited in any of Claims 2, 3 or 4 wherein the solution has a pH of about 7 or below.

9. An aqueous acidic cleaning composition, which has less than about two percent by weight inorganic salts, for ferrous metals comprising:
an acid; and, on a total weight basis, from about 0.1 to about 50 percent by volume of the composition of a glycoside having the formula R(OG)x wherein R is an aliphatic hydrocarbon radical having from 1 to 25 carbon atoms or is a radical with the formula R1(OR2)n which does not have more than 25 carbon atoms and wherein n = 0 to 24 and R1 and R2 are aliphatic hydrocarbon radicals, G is the residue of a saccharide moiety selected from the group consisting of fructose, glucose, mannose, galactose, talose, gulose, allose, altrose, idose, arabinose, xylose, lyxose, ribose, alkoxylated derivatives of any of the foregoing saccharides, or mixtures thereof, and x is 1 to 30.

10. A composition as recited in Claim 9 wherein G is glucose, the composition has a pH in the range of about 0.1 to about 4, x = 1 to 10 and R is an alkyl group which is a straight chain or branched having 4 to 13 carbon atoms.

11. A composition as recited in Claim 10 wherein the glycoside comprises, on a total weight basis, from about 1 to about 20 percent by weight of the acidic aqueous composition.

12. A composition as recited in Claim 10 wherein the glycoside comprises, on a total weight basis, from about 1 to about 10 percent by weight of the acidic aqueous composition.

13. A composition as recited in Claim 12 wherein R is an alkyl group which is a straight chain or branched having 9 to 13 carbon atoms.