US2252985A - Compounded oil - Google Patents

Description

Patented Aug. 19, 1941 COMPOUNDED OIL John T. Rutherford and Robert J. Miller, Berkeley, Calm, assignors to Standard Oil Company of California, San Francisco, Call, a corpora- 1 tion of Delaware No Drawing. Application May-c, i939,

\ Serial No. 272.155

24 Claims. (01. 252'-s9) This invention relates to a new andmsel'ul composition of matter and involves a composition comprising a hydrocarbon, such as a viscous hydrocarbon oil, and an alkaline earth metal salt of sulfur-containing substituted acids of phosphorus.

The production of improved hydrocarbon oils, and particularly of lubricating oils having desired characteristics, has been the subject of extensive and oxidize when subjected to high temperatures.

This deterioration is evidencedby the deposition of adhesive deposits on hot metal surfaces over which the hydrocarbon oil may flow. It is important that resistance to such deterioration be imparted to hydrocarbon oils, particularly to lubricating oils, in order that such compositions may be relatively free from the. tendency to form such deposits even under high temperatures and severe operating conditions. A direct result or this type of deterioration during lubrication of in temal combustion engines. such as engines of the Diesel type, is the tendency of the oil to cause or permit the sticking of piston rings.

The crankcase lubricant in internal combustion engines is subjected to extremely severe operating conditions and in engines of the Diesel type the lubricant encounters in the piston ring zone temperatures of from approximately 425 to 650 F. and pressures from the oxidizing combustion gases as high as 750 to 1150 lbs. per sq. in. Addition agents which render hydrocarbon oils resistant to deterioration by heat at high temperature levels in the order of those above mentioned usually impart to the oil the ability to inhibit piston ring sticking in internal combustion engines and permit longer periods of operation of such engines without the necessity oi major overhauls heretofore occasioned by stuck piston rings.

It should be noted that stabilizing agents which are effective at low temperatures to impart increased stability to hydrocarbon oils, or which are effective at temperatures even as high as 200.

stabilizer at atmospheric temperatures, or even temperatures as high as 200 to 300 F., gives no adequate basis for predicting the action of the same stabilizing agent at materially higher temperatures and under more severe operating conditions. The disclosures in the prior art relative to such stabilizers therefore cannot serve as a guide for one seeking stabilizing agents or oxidation inhibitors efiective at higher temperature levels. The phenomena. involved are catalytic in nature, arehighly empirical, and require extensive experimentation to determine the action of a or 250 F., areoften inefl'ective under the more given type of addition agent.

The present invention involves the discovery that dispersion of alkaline earth metal salts of sulfur-containing substituted acid of phosphorus in hydrocarbon oils, such as mineral lubricating oil, imparts new, unpredictable and highly desirable properties to the composition. These new properties render the compounded oil particularly useful for various purposes. Although increased resistance to deterioration at high temperature levels comprises one 01' the principal advantages of the compounded oil of this invention, it is to be understood that the invention is not limited to this feature and that difierent compounds of the general type involved herein vary in their degree of effectiveness. In general, however, it has been discovered that the new compositions herein disclosed are. more stable to heat than is a hydrocarbon oil with which the compositions are compounded. The new compositions of this invention are therefore useful where resistance to deterioration by heat is important. An example of such utility other than as a lubricating oil comprises use as a heat transfer fluid where it may be desirable to inhibit or prevent the formation of a deposit on the metal surfaces from or to which heat is beingconveyed. Likewise, the increased resistance to oxidation imparted to the oil by the compounds of this invention will find various applications as, for instance, in insulating, switch or transformer oils.

It has also been discovered that calcium salts of sulfur-containing substituted phosphoric acids, in particular, have a combination of properties heretofore unknown and particularly desirable in compounded lubricating oils, namely, the ability to inhibit oxidation and impart to lubricating oils increased resistance to deterioration by heat, the

' ability to inhibit piston ring sticking, freedom from the production of increased wear on cylinder walls and piston rings as compared with uncompounded mineral oils, not only low corrosivity as respects the chemical action or the compounded 2 2,252,985 n on bearing metals, such as cadmium-silver ing at least twelve carbon atoms in the molecule.

and copper-lead alloys, but the capacity to actually'lnhibit the corrosive action of highly P oils on these bearing metals, and the capacity to inhibit piston ring sticking and ring slot carbon formation in parafllnic lubricating Oils of the Pennsylvania type. Although various compounding agents are known which are capable of inhibiting piston ringsticking, the discovery of specific agents capable of imparting the above combination of properties to hydrocarbon oils represents an unobvious and important contribution.

Alkaline earth metal salts of sulfur-containing substituted acids of phosphorus which may be added to hydrocarbon lubricating oils to provide a new composition of matter of the type herein involved comprise compounds which may be represented by the general formula:

where M is an alkaline earth metal selected from Group II of Mendelyeevs Periodic Table of the Elements. Examples of such metals are calcium, strontium and barium. For the purposes of this invention, in its broader aspects, magne'sium may also be classified as an alkaline earth metal. In the above formula R may be alkyl, aryl, alkaryl, aralkyl, or cyclic non-benzenoid groups; X and Y each are either sulfur or oxygen and sulfur; H is hydrogen; P is phosphorus; a, b, d and 2 represent small whole, numbers, and c may be zero or a small whole number.

The salts of this invention are preferably formed from substituted acids of pentavalent phosphorus of one or more of the following type formulae:

where R and R may be alkyl, aryl, alkaryl, aralkyl, or cyclic non-benzenoid groups. Substituted acids containing at least approximately twelve carbon atoms are preferred. Examples di-ester of mono-thiophosphoric acid of preferred type acids are alkyl or alkaryl sulfur-containing substituted phosphoric acids hav- However, it is to be understood that the broader aspects of the invention include other types of sulfur-containing substituted acids of phosphorus containing more than twelve carbon atoms. Additional examples of such acids which may be used in forming the alkaline earth metal salts of the present invention are as follows:

mono-thioester o! phospbonic acid mono-ester oi iritblcphosphonic acid mono-thioesier oi trithiophosphonic acid alkyl, aryl, alkaryl, aralkyl, or cyclic non-benzenoid groups.

In general, alkaline earth metal salts of sulfur-containing substituted derivatives of acids of phosphorus, such as phosphorous acid, HaPO-s; hypophosphoric acid, HzPOa; ortho- Dhosphoric acid, H3PO4; pyrophosphorlc acid, HiPzO-z; monothiophosphoric acid. HzPSOs; dithiophosphoric acid, HaPSaOa; trithiophosphoric acid, HaPSaO; tetra-thiophosphorlc acid; H.1PS4; thiopyrophosphoric acid, HJaSw; and trithiopyrophosphorlc acid, H4PaSaO4, fall within the broadest aspects of the invention. By substituted acids" or substituted derivatives of phosphorus, whenever used herein, it is intended to designate acids of phosphorus containing an organic group of the type previously listed. The organic group may be either directly attached to the phosphorus atom of'the compound or attached thereto through an intervening atom such as oxygen or sulfur. The term sulfurcontainlng" is intended to designate compounds in which either the original acid of phosphorus or the organic derivative thereof contains sulfur.

The preferred acids are sulfur-containing substituted acids of pentavalent phosphorus and the preferred salts comprise calcium salts of such acids. Examples of preferred salts are calcium cetyl thiophosphate, calcium cetyl phenyl thiophosphate, and a calcium salt of the acid phosphoric acid ester of di-(p-hydroxy phenyl) sulfide. Salts such as calcium thiccresyl phosphate are less effective than the previously recited compounds but improve various properties of the oil. particularly its resistance to oxidation. U

Additional examples of salts within'the scope of the invention are calcium lauryl thiophosphate, calcium octadecyl thiophosphate, calcium spermol thiophosphate, calcium oleyl thiophosphate, calcium spermenyl thiophosphate, calcium di-(amyl phenyl) thiophosphate, calcium naphthenyl thiophosphate, calcium di-cyclohexanyl thiophosphate, calcium tetra-chloro-octadecyl thiophosphate, calcium di-(6-chloro. 2- phenyl phenyl) thiophosphate, calcium di-(3 methyl, 4-chloro-phenyl) thioph'osphate. barium lauryl' thiophosphate, barium octadecyl thicphosphate, barium spermol thiophosphate, barium oleyl thiophosphate, barium spermenyl thiophosphate, barium di-(amyl phenyl) thiophosphate, barium naphthenyl thiophosphate,

instance, the calcium salt may be manufactured barium dl-cyclohexanyl thiophosphate; barium. tetra-chloro-octadecyl vthlophosphate, barium di-(B-chloro, 2-phenyl phenyl) thiophosphate, and barium di-(3-methyl, 4 -chloro-phenyl) thiophosphate. a

The sulfur-containing substituted acids of phosphorus utilized for preparing the alkaline earth salts of this invention may contain organic substituents other than pure hydrocarbon groups. The organic radical in the acid of phosphorus may comprise, in addition to the carbon and hydrogen, substltuents such as the halogens, chlorine or bromine, hydroxy, suii'hydryl and similar groups. Likewise, the sulfurin the sulfur-containing atom need not necessarily be directly attached to the phosphorus atom. An acid which illustrates these types of compounds comprises the phosphoric. acid ester of di-(phydroxy phenyl) sulfide.

The acids of phosphorus utilized in the present composition may be prepared by various methods. For example, a mixture of ahigher alcohol and phosphorus pentasulflde, a mercaptan and phosphorus pentoxide, a mercaptan and phosphorus pentasulfide or a three-component mixture, such as a mercaptan, phosphorus pentoxide by precipitation as follows: Water and caustic potash are charged to a mixer and heated to a temperature of 180 F. The acid is added, thereby forming an a1 1 salt. An aqueous calcium chlor'de solution incorporated with violent agita ion during precipitation to prevent inclusion of the potassium salt. The precipitated curd is washed free of inorganic salts with hotiresh water. Mineral oil is then added and the solution is dehydrated 'as by heating to a temperature of 300-330 F. The concentrated oil solution so obtained may conveniently be ,used for mixing or blending with other oils to prepare the completed product.

The alkaIine earth salts may also be prepared in the non-aqueous environment by the reaction of a metal carbide with the free substituted acid.

For example, calcium carbide may be reacted 20 with free cetyl thiophosphoric acid to yield acetylene and anhydrous calcium cetyl thiophosphate.

By way of illustration and to demonstrate th unusual properties possessed by the compounded oils of this invention, test data are given in Table I:

Table I Oxidator P t test; c.c. tHoursI ercen oxygen 0 stic Compound Method of manufacture of acid salt absorbed piston in 2.5 rings 1 hours COMPOUNDED IN ACID REFINED WESTERN OIL S. A. E.

Mineral nil 0 324 Calcium phosphate of p-hydroxydxp-Hydro y lp nylsulflde and zot 1 76 phenylsulfide. fphospholeum. Calcium thiocresyl hos hate" Tluoeresol and P20t+phosphoieum 1 calcliaum cetylthiop osp ate... Cetyila1cohol+P S 1 0 0 .05 Calcium cetyiphenylthiophosphate... Cety1phenol+PzS5 1 Calcium thiocresyithiophosphate.--. ThrocresoH-PzS; 1

COMPOUNDED IN PENNSYLVANIA OIL S. A. E. 30

Mineral oil 0 302 Calcgum cetylphenylthiophosphate... Cety lphenol+P2Sr 1 13 n o 0 .5 165 Calcium cetylphcnylthiophosphate+ do .5+.25 1;

calcium cetylphenate. Calcium thiocresy1thioph0Sphate Thiocre'sol+PSt 1 1 88 and pyrophosphoric acid, may be directly fused in proportions to give acid esters. The reaction by which the substituted phosphoric acid is formed in the last mentioned three-component mixture is believed to be represented by the following equations:

the alkali metal salt of the above acid may be dissolvedin aqueous solution and the alkaline earth metal salt precipitated therefrom. For

It will be observed that all of the compounding 1 try, 1936, vol. 28, page 26, and was carried out in the present examples at 340 E, which represents" very severe conditions. t

In the piston ring sticking tests a single cylin- -der, 2%" bore, 2 stroke, Lauson gasoline engine was operated under extremely severe conditions for the purpose of developing fully piston ring sticking and piston gumming tendencies under circumstances simulating severe operating conditions encountered in the field. Operation of the motor during test was continuous at 1600 R. P. M. except for periodic shut-downs at fifteen-hour intervals for inspection. The jacket temperature was maintained at'approximately 375 F. and the sump oil temperature at approximately 220 F. during the test.

' The compounding agents of this invention are outstanding in that they are more eflective to inhibit piston ring sticking in Pennsylvania type oils than are any compounds heretofore found.

pounding agents are also effective to inhibit the corrosive action or paraflinic oils on'bearing metals, such as copper-lead or cadmium-silver alloys. Corrosion data, together with data on the increase in viscosity of the oil and A. S. T. M. insolubles, are given in Table II:

'- Table II Calcium Calcium Y Mineral cetylt g f}; oil Penn. henylf s. A. Lao tfiiophoscetylphenate Percent salt 1 .6+.25 Stri corrosiontest:

g.loss72hr.- Cu-Pb 19.4 +1 5.0 Cd- 0.1 0.1 as Percent increase in viscostyat 00 F 1o 0 1o Ins. in A.S.T.M. naphtha,

.M 12 o a a The above corrosion tests were carried out in the following manner: Glass tubes 2 inches in diameter and 20 inches long were immersed in an oil bath, the temperature of which was automatically controlled to within 21 F. of the test temperature, which was 300 F. Approximately the oils; in most cases the copper-lead and cadmium-silver bearing alloys were tested simultaneously in the same sample 01' oil. The weight loss of each strip was recorded. Before weighing, each strip was washed in petroleum ether and carefully wiped with a soft cotton cloth. The duration of the test was '12 hours.

The compounding agents herein disclosed may have one or more advantages, depending upon the particular compound selected. the proportion utilized, and the environment which the lubricating oil is to encounter. It should be observed, for example, that even though a compounded oil may be somewhat corrosive to copper-lead or cadmium-silver bearing metals, Babbitt bearings are little, it at all, affected by such corrosive action. .Hence, compounded oils which may not be particularly desirable for lubrication of copper lead or cadmium-silver bearings may be highly useful and extremelyadvantageous in conjunction with theoperation or internal combustion engines having bearings of Babbitt or other corrosion-resistant bearing metals. The present invention in its' broader aspects is therefore not limited to a particular compound having 'all or the greatest number or advantages, but

embraces various oi the less advantageous addition agents which will find utility in particular applications where all the possible improvement in properties may not be required or where the standard or performance may not be so high.

Present experience indicates that where the properties desired involve the ability to stabilize lubricating oils under severe operating conditions such as those encountered in the lubrication of pistons and pistonrings 01. internal combustion;- englnes of the Diesel type, alkaline earth salts of sulfur-containing substituted acids of pentavalent phosphorus containing more than twelve carbon atoms in the molecule and preferably containing an alkyl or alkaryl substituent should be utilized.

p V 9,952,085 a v As has been pointed out hereinbeiore, the comi A moderately acidreflned Watern'naphthenic function more efl'icicntly in such a base oil than in a highly parailinic oil stock or a highly refined Western oil. However, it is to be understood that the invention is not limited to such a base stock since various 0! the present compounds, particularly the calcium salts, are more eflective in inhibiting oxidation and corrosion effects in parafllnic oilstocks thanare any compounds so iartested.

The proportion of the alkaline earth .metal salts of substituted acids of phosphorus added to mineral lubricating oils may vary widely dependmg on the uses involved and the properties desired. As li ttle as 0.05% by weight of the compound gives measurable' improvements, particularly as respects inhibiting oxidation and color stability of the compounded oil. From approximately 0.25 to approximately 2% of the compound may be added to lubricants where increased stability, in internal combustion engines and resistance to piston ring sticking comprise the principal properties desired. Solutions containing more than 2% 01' the compounds in mineral oil may be utilized for the purpose of preparing' lubricating greases and concentrates capable of dilution with lubricating oils and the like. Such higher concentrations comprise a convenient method of handling the compounds and may be used as addition agents for lubricants in general as well as for other purposes.

The alkaline'earth metal salts of this invention may be added to hydrocarbon oils containing other compounding ingredients sucii as pour point depressors, oiliness agents, extreme pressure addition agents, blooming agents, compounds for enhancing the viscosity index of the hydrocarbon oil, corrosion inhibitors and the like. The invention in its "broader aspects embraces mineral hydrocarbon oils containing, in addition to metal salts of the substituted acids of phosphorus, thickening agents and/or metal soaps in proportions or in amounts insuflicient to form greases, as in the case of mineral castor machine oils or other compounded liquid lubricants.

The compounds of this invention may be added to oils other than hydrocarbon lubricating oils, for example, fueloils, non-drying vegetable or animal oils, or synthetic oils, such as olefin polymers and hydrogenated oleiln polymers.

While the character of the invention has been described in detail and numerous examples of the composition given, this has been done by way of illustration only andwith the intention that no limitation should be imposed on the invention thereby. It will be apparent to those skilled in the art that numerous modifications and variations of the illustrative examples may be effected in the practice 01' the invention which is of the scope of the claims appended hereto.

We claim:

1. A composition of matter comprising a hydrocarbon oil subject to deterioration at elevated temperature, and an alkaline earth metal salt of a sulfur-containing substituted acid of phosphorus having an organic substituent therein, said salt being present in. an amount sumcient substantially to inhibit said deterioration.

2. A composition of matter comprisinga hydrocarbon oil subject to deterioration at elevated temperature, and a calcium salt 01' a sulfurcontaining substituted acid of phosphorus having an organic substituent therein, said salt being present in an amount sufficient substantially to inhibit said deterioration.

3. A composition of matter comprising a hydrocarbon oil subject to deterioration at elevated temperature, and a barium salt of a sulfur-containing substituted acid of phosphorus having an v containing substituted acid of phosphorus having an organic substituent therein, said salt being present in an amount suflicient substantially to inhibit said deterioration.

5. A composition of matter comprising a hydrocarbon oil subject to deterioration at elevated temperature, and an alkaline earth metal salt of a sulfur-containing substituted acid of pentavalent phosphorus having an organic substituent therein said salt being present in an amount suflicient substantially to inhibit said deterioration.

6. A composition of matter comprising a hydrocarbon oil subject to deterioration at elevated temperature, and a calcium salt of a sulfur-containing substituted acid of pentavalent phosphorus having an organic substituent therein, said salt being present in an amount suflicient substantially to inhibit said deterioration. 'l. A composition of matter comprising a hydrocarbon salt subject to deterioration at elevated temperature, and a barium salt of a sulfur-containing substituted acid of pentavalent phosphorus having an organic substituent therein, said salt being present in an amount suflicient substantially to inhibit said determination.

8. Awomposition of matter comprising a hydrocarbon oil subject to deterioration at elevated temperature, and a magnesium salt of a sulfurcontaining substituted acid of pentavalent phosphorus having an organic substituent therein, said salt being present in an amount suflicient substantially to inhibit said deterioration.

9. A stabilized liquid. lubricant comprising a lubricating oil and an alkaline earth metal salt of a sulfur-containing substituted acid of phosphorus having an organic substituent therein, said salt being present in an amount .suflicient to stabilize said oil against deterioration during use.

10. A stabilized liquid lubricant comprising a lubricating oil and an alkaline earth metal salt of a sulfur-containing substituted acid of pentavalent phosphorus having an organic substituent therein, said salt being present in an amount sumcient substantially to stabilize said oil against deterioration during use.

11. A composition of matter comprising a hydrocarbon oil subject to deterioration in the presence of oxygen, and an alkaline earth metal salt of a 'thio-ester of phosphoric acid, said salt being present in an amount suflicient substandrocarbon oil subject to deterioration in the presence of oxygen, and a barium salt or a thio-ester .of phosphoric acid, said salt being present in an amount sufllcient substantially to inhibit said deterioration. Y i

14;. A composition of matter comprising a hydrocarbon oil subject to deterioration in the pres- 4 ence of oxygen, and a magnesium salt of a thinester of phosphoric acid, said salt being present in an amount sumcient substantially to inhibit said deterioration.

15. A composition of matter comprising a hydrocarbon oil subject to deterioration in the presence of oxygen, and an alkaline earth metal salt of an ester of a thiophosphorie acid, said salt being present in an amount sufilcient substantially to inhibit said deterioration.

16. A" composition of matter comprising a hydrocarbon oil subject to deterioration in the presence of oxygen. and a calcium salt. of an ester of a 'thiophosphorie acid, said salt being present in an amount sufficient substantially to inhibit said deterioration.

1'7. A composition of matter comprising a hydrocarbon oil subject to deterioration in the presence ofoxygemand a barium salt of an ester of a thiophosphoric acid,'s'aid salt being present in an amount sufiicient substantially to inhibit said deterioration.

18. A composition of matter comprising a hydrocarbon oil subject to deterioration in',the presence of oxygen, and a magnesium salt of an ester of a thiophosphoric acid, said salt being present in an amount suflicient substantially to inhibit said deterioration.

19. A stabilized liquid lubricant'comprising a paraflinic lubricating oil and more than approximately 0.05% by weight based on the oil of an alkaline earth metal salt of a sulfur-containing substituted acid of phosphorus having an organic substituent therein.

20. A stabilized liquid lubricant comprising a paraifinic lubricating oil and more than approximately 0.05% by weight based on the 'oil of a calcium salt of a sulfur-containing substituted acid of phosphorus having an organic substituent therein. I

21. A compounded lubricant comprising a inbricating oil and from approximately 0.05% to approximately 2% by weight based on the oil of an alkaline earth metal salt of a sulfur-containing substituted acid of pentavalent phosphorus having more than approximately twelve carbon atoms in the molecule.

22. A compounded lubricant comprising 'a lubricating oil and from approximately 0.05% to approximately 2% by weight based on the oil of a calcium salt of a sulfur-containing substituted acid of pentavalent phosphorus having more than approximately twelve carbon atoms in the molecule.

23. A compounded lubricant comprising alubricating oil and 'from approximately 0.05% to approximately 2% by weight based on the oil of a barium salt of a sulfur-containing substituted acid of pentavalent phosphorus having more than approximately twelve .carbon atoms in the molecule 24. A compounded lubricant comprising a lubricating oil and from approximately 0.05% to approximately 2% by weight based on the oil of a magnesium salt of a sulfur-containing sub CERTIFICATE 013 common 0N.

Patent-"K0. 2,252,985. August 19 191 1. 1 Y I Jon 1. mmnmnn, ET AL.

It is hereby certified that error appear; in the printed specification of the above mmbered patent requiring correction as follows: Page 5,,first column, line 514., 0111117, for the word "salt" read --oil-; line 59, sane. claim, for "determination" read. --deterioration--; line 51, claim 9, after 'sufficiefit" insert -subatentially--; and that the said Letters Patent ahofild be read with this correction therein that the some may conform to the record of the case in the Patent Office.

Signed and sealed this 28th da of October, 1,. D 1911.1.

Henry Van Arsdale, H (Seal) Acting Conmis sioner of Patents.-

DISCLAIMER 2,252,985.-John T. Rmhmwd and Robert J. Miller, Berkeley, Calif. CoMPoUNbEo OIL. Patent dated August 19, 1941. Disclaimer filed May 10, 1944, by v the assignee, Standard Oil Company of California. 7 Hereby enters this disclaimer to claims 1,- 2, 4, 5, 6, 8, 9, 10, 11, 12, 14, 15, 16, 18, and 24 of said patent. I

[Ofiieial Gazette Jane 6, 1,944.]

CER'iPIFICATE 0F commcnonl Patent R0. 2, 252, 985. w

August 19, 19!;1. Jean *1. RUTHERFORD, ET AL. V

It is hereby certified that error appeare in the printed specification of the above numbered patent requiring correction as follows: Page 5, first line 31;, clum'r, for the word "salt" read -oi1--; line 59, same. "determinetion" read -deterioration-; line 51, claim 9, after Patent column,

claim, for "gufficiexit" insert --substantially-; and that the said Letters shoizld be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 28th day of October, A. D 191:1.

Henry Van Arsdale,

(s l) Acting Commissioner of Patents;

DISCLAIMER 2,252,985.J0hn T. Rutherford and Robert J. Miller, Berkeley, Calif. COMPOUNDED OIL. Patent dated August 19, 1941. Disclaimer filed May 10, 1944, by the assignee, Standard Oil Company of California. 7 Hereby enters this disclaimer to claims 1, 2, 4, 5, 6, 8, 9, 10, 11, 12, 14, 15, 16, 18, and 24 of said patent.

[Ojfic'ial Gazette June 6', 1944.]