Patented Nov. 5, i946 2,41%,659 HUBBKCANT CQEIPGSEEI‘KQN .‘ichn ,3. Giaminaria, Weodhm'y, N.‘ 3., asngnor to Balcony-Vacuum @il Qompuny, incorporated, a corporation of New York No Drawing, Application March 39, 194d, :‘derial No. 528,783 - 9 Claims. (oi. ass-sac) ii ri’his application is a continuation-in-part of substituted with relatively long-chain alkyl copending application Serial No. 390,586, ?led April 26, 194i, and relates to hydrocarbon olls‘of the type employed as lubricants, dielectrics, and groups, such as those characterizing parafin wax (predominantly alkyl groups or" at least twenty carbon atoms). ' ‘ the like. Primarily, the present invention is con-_ 5 A compound or reaction product of the type cerned with improving certain characteristics of contemplated herein may be broadly described such oils, particularly pour point and viscosity as an oil-miscible metal salt of a thio acid of phosphorus or, more speci?cally, as a metal salt of index, and stabilizing the oils against the deteri- - crating in?uences encountered under operating conditions. ’ ~ \ a partial ester‘ ofv a ‘chic acid of phosphorus, ob~ 10 .tained by reacting Pass with a compound having as is well known to those skilled in the art, petroleum oils of the viscous type re?ned for use _ as lubricants or the like are generally subject to deterioration in service with theiiormation of the general formula ROH wherein R represents an alkaryl oil soluhilizing hydrocarbon group of the type described above and then reacting the - product thus obtained with a reactive metal com acidic materials, sludge, and other oxidation prod 15 pound. Although, as aforesaid, we do not wish ucts which reduce their usefulness. li/l'otor oils, to be bound by any theory of reaction or formula for example, and particularly those used in the of the product, it does appear that under certain lubrication of Diesel engines, are subjected to conditions of reaction and reactants the ultimate 'relatively severe conditions which accelerate the products obtained are the metal salts of wax development of acid and sludge in the crank case 20 substitut'ed diaryl dithiophosphcric acid, the gen and the accumulation of lacquer and carbona eral structural formula of which may be expressed ceous material about the piston rings, which cause - as follows: the rings to stick and which obstruct the oil slots therein. The acidic materials developed tend to - corrode certain hard alloy bearing metals such as those having the corrosion-susceptibility of cadmium-silver alloys and the like. . This invention is based upon the discovery of a novel class of addition agents which when wherein R ‘and R’ represent alkaryl hydrocarbon groups in which the alkyl substituents correspond to high molecular Weight aliphatic hydrocarbon blended in minor proportions with hydrocarbon 30 materials, such as para?in wax and are predomi , oils of the type above-referred to will effectively retard the deterioration imposed-by either mild or severe conditions of use and will therefore . nantly groups of at least twenty carbon atoms; and M represents the hydrogen equivalent of a metal. greatly increase the useful life of the oil. These materials which, as aforesaid, possess The class of compounds or reaction products 35 pour-depressing properties in addition to other contemplated herein as addition agents for lubri oil characterizing properties may, for purposes of cating oils and the like are organic compounds illustration, betypiiied by the metal salt of a containing sulfur, phosphorus, and metal in chemical combination or a mixture thereof pre waxnsubstituted diphenyl dithiophosphoric acid and may be represented by the following general dominantly comprised of compounds obtained by 40 formula reacting phosphorus pentasul?de with an alkyl substituted phenol. and then introducing metal into the product thus obtained by reaction with a metal hydroxide or the like. These compounds or reaction products contain a hydrocarbon group or groups of a character which will impart oil . miscibility or oil-solubility to the compound or reaction product. The present invention contemplates compounds of the class described wherein the oil-solubilizing action is obtained from an alkylated aryl nucleus wherein Rn represents at least one alkyl group having at least twenty carbon atoms or an alkyl depressant properties to the compound or reac group corresponding to the aliphatic hydrocar tion product. The pour-depressant property is bons characterizing parai?n wax, and M is as obtained by employing an aryl nucleus which .is 55 de?ned above. As aforesaid, howeventhe for which, in addition to oil-solubility impartspour 2,410,650 3 phenyl dithiophosphoric acid (3-16) in approxi mulae and nomenclature 'used herein are based upon our theory of the reaction and are intended mately 25 per cent mineral oil- blend. to represent the reaction product obtained rather than a speci?c chemical compound in each in stance.‘ - The stannous salt of "Wax-substituted diphenyi .dithiophosphoric acid”'was obtained by dissolv ing 100 grams of the acid product obtained by the procedure last described above (dissolved in ‘ It is to be understood that the aryl nucleus in compounds of the type represented by the fore going general formulae (I and 11) may be mono or poly-cyclic and, as aforesaid, the alkyl sub 300 grams of mineral oil) in 100 cc. of butyl alcohoLadding 1.5 grams of metallic sodium, and ' heating the mixture at the re?ux temperature of stituent thereon should correspond to an alkyl 10 the alcohol until the sodium was all reacted. A group of su?iciently high molecular weight to im part to the compound pour point-depressing and butyl alcohol solution of stannous chloride (6.2‘ .- viscosity index-improving action in addition to , ture slowly heated to 150° C. while the alcohol grams of SnClz) was then added and the mix oil miscibility. For alkyl substituents that will impart these properties, particular preference‘ is was distilled oil. The mixture was then cooled, diluted with benzol, and ?ltered through a ?lter- _ ' given to alkyl groups of at least twenty carbon aid clay to remove NaCl, after which the solvent atoms. was distilled o? to obtain the ?nished product. As to the metallic constituent M, it ‘appears The barium salt of, “wax-substituted diphenyl that any metal may be used. The alkaline earth dithiophosphoric acid” was prepared by forming metals are preferred, with particular preference 20 a reaction mixture consisting of 100 grams of the given to barium. Other representative metals “wax-substituted diphenyl dithiophosphoricacid" which may be used are zinc, tin, aluminum, co in 300 grams of mineral oil, 11 grams of balt, nickel, chromium, the alkali metals, etc. , Ba(OH)2.8Hz0 and 100 cc. or benzol. The mix As aforesaid, the reaction products contem ture was gradually heated to 150° C., the benzol plated herein as typi?ed by the metal salts of the 25 and the water formed in the reaction thereby be; partial esters of dithiophosphoric acid may be ing distilled off. ,'After the reaction mixture was prepared by ?rst forming the corresponding par cooled, it was diluted with benzol, ?ltered through tial ester of dithiophosphoric acid by any known ‘ a ?lter-aid clay to remove unreacted method, such as that described by P. S. Peshchi Ba (OH) 28H2O, muka (J. Russ. Phys. Chem. Soc. 56, 11 (1925) ); 30 _ (Chem. Ab. 19, 2808) , wherein phosphorus penta~ and the solvent was distilled oi! to obtain the sul?de is reacted with an alcohol, and then re - ?nished product. acting the partially esteri?ed acid thus formed a Typical metal salts of partial esters of dithio with a metallic hydroxide to form the metal salt phosphoric acid which have been synthesized and of the partial ester of dithiophosphoric acid. 35 demonstrated to be effective addition agents for The reactions involved can probably be expressed hydrocarbon oils of the type used in lubricants by the following equations, although, as afore and the like are the following: - said._we do not wish to be bound :by any theory of. Stannous _di(wax-phenyl) dithiophosphate reaction. Barium di(wax-phenyl) dithiophosphate (A) 4ROH+P2S5+2 (R0) zPSSH-I-HaS (B) (R0) aPSSH-i-MOH.» (R0) zPSSM-I-HaO 40 As a modi?cation of the foregoing procedure reaction (B) may be carried out with sodium or to stabilize and improve the various properties of various viscous hydrocarbon oils. 45 EXAMPLE 2 potassium hydroxide (M'OH) to form the corre sponding salt (R0): PSSM', which can then be reacted with a water-soluble salt of another metal,‘ CORROSION Tssr v The corrosion-inhibiting action of these com pounds was demonstrated in the so-called cata such; as’ zinc chloride or stannous chloride, to yield “by metathesis‘; the substituted dithiophos phoric ‘acid saltj'of the‘ second metal. Further detailsfwfthe procedure which may be 50 lyzed Underwood oxidation test, which is de scribed in a pamphlet, dated August 1, 1938, of the Research Laboratories Division of the Gen followed in synthesizing the compounds contem plated herein, may be obtained from the follow ' eral Motors Corporation, entitled f‘Underwood ox ing illustrative examples. idation testing apparatus.” The following results EXAMPLE 1 Min-AL SALTS or 55 were obtained by using a motor oil of 210 seconds Dn'mornosrnoarc - The following examples will illustrate the effec - tiveness of the compounds contemplated herein ~Acm Saybolt viscosityat 130° F. with the addition of su?icient iron naphthenate to be equivalent to 0.01 per cent iron oxide to act as a catalyst. Bearings containing a cadmium-nickel surface Wax-substituted ‘was ?rst prepared by 60 were used and the Mg loss in bearing weight and the acidity bf the oil (N. N. value) were deter the Friedel-Crafts condensation of chlorinated mined after ?ve hours of test. ' para?in wax (16 per cent chlorine content) with phenol in the ratio of 1 molecular part phenol to 3 atomic parts chlorine in the chlorwax. The‘ Compound added egg‘; N. N. 65 wax-substituted diphenyl dlthiophosphoric acid was obtained by making a reaction mixture of 100 grams of the wax-phenol, 8.1 grams of Past, and 300 grams of mineral oil of Saybolt viscosity of 6'? seconds at 210° F. This‘ mixture was heated at 100° C. until the evolution of H28 had sub stantially stopped (about 15 or 20 hours). The clear solution was then blown with a stream of nitrogen to remove entrained H118, to obtain the ‘ product which, for purposes of identi?cation herein we may refer to as wax-substituted di None _______________________________________ __ Ba salt of wax-substituted diphenyl dithiophosphoric acid (3-16) ________ ._ 1 789 13.4 40 _ 2. l EXAMPLE 3 Form Dnrxsssam AND V. I. IMPROVEMENT‘ As aforesaid, the so-called “wax”-substituted compounds have‘the properties of acting as pour point-depressants and viscosity index-improvers. 2,410,650 6 2. A lubricant composition comprising a major These properties are demonstrated by the re sults set forth in, Tables 11 and m below showing proportion of a viscous hydrocarbon oil and an oil-miscible metal salt of a wax-phenyl-sub pour point-depressing and V.. I. results, I respec stituted thio' acid of phosporus in an amount suf tively. on typical motor oils with and without the addition agent. Table II ' g A. S. 'I‘. M. pour .Compound blended with motor oil of 67 sec. points on on Hands Baybolt viscosity at 210° F. ' ‘ ' * 9% 340% ° F. None _______________________________________ ._ +20 ° F. %% . ?cient to exert detergent and anti-corrosive prop erties in the oil under heavy duty service, said wax group containing at least twenty carbon atoms. dithiophosphoric acid (3-16) ____________________ _. —10 -20 - to exert detergent and anti-corrosive properties ° F. in the oil under heavy duty service, said wax group ............ __ Barium salt of waxsubstituted *diphenyl . 3. A lubricant composition comprising a major 10 proportion or a viscous hydrocarbon oil and an oil-miscible metal salt of a wax-aryl-substituted thio acid of phosphorus in an amount su?lcient 15 containing atleast twenty carbon atoms. 4. A lubricant composition comprising a major proportion of a viscous hydrocarbon oil and an oil-miscible‘ metal salt of a wax-substituted diphenyl dithiophosphoric acid in an amount suf Table III \ Kinematic viscosity Compound blended with C v ‘I lubricating oil‘ 20 ?cient to exert detergent and antil-corrosive prop erties in the oil‘ under heavy duty service, said ‘ 100° F. Per can't None ____________________ __ 210° F. , , o wax group containing at least twenty carbon atoms.’ 5. A lubricant composition comprising a major . 29. 56 4. 72 76. 7 32. 28 5. 04 - 86. 0 proportion of a viscous hydrocarbon oil and an . Waxeuhstituted diphenyl dithiophosphoric acid (3-1 _______________ __,___ Barium salt of wax-substt‘ tuted diphenyl 1 dithio- - phosphoric acid (3-16)... 1 oil-miscible alkaline earth metal salt of a wax substituted diphenyl dithiophosphoric acid in an amount 'su?icient to exert detergent and anti= I 33.06 I5. 15 89.6 corrosive properties in the oil under heavy duty The'parenthetical expression “(3-16)” used in 30 service, said wax group containing at least twenty carbon atoms. 6. A lubricant composition comprising a major Tables I, II and III and in Example 1 above indi cates the number of atomic proportions (3) of I chlorine in the chlorwax reacted with 1 molecular proportion of a viscous hydrocarbon oil and an oil-miscible barium salt of a wax-substituted part of phenol and the percentage (16) of chlorine 35 diphenyl dithiophosphoric acid in an amount in the chlorwax used in this reaction from which su?icient to exert detergent and anti-corrosive the wax phenol was obtained. This wax'phenol properties in the oil under heavy duty service. (3-16) provides the wax-substituted phenyl sub said wax group containing at least twenty carbon stituents in the salts disclosed herein, as described in Example 1. ‘ atoms. ' ‘ ' 7. A lubricant composition comprising a majo The compounds or reaction products contem plated herein may be used in various amounts de pending upon the character of the. oil and the severity of the conditions under which it is to be proportion of a viscous hydrocarbon oil and an oil-miscible zinc salt 01’ an acidic reaction prod used. In general it appears that satisfactory im- , having the formula: uct obtained ,by reacting PzSs with a compound ' provement may be obtained with amounts rang ing from about 0.01 per cent to about 5.0 per cent. It ‘is to be understood that while I have herein described certain speci?c compounds and pro cedures to illustrate the invention, such speci?c ,, examples are illustrative only and the invention, inv an amount sumcient to exert detergent and anti-corrosive properties in the oil under heavy duty service, wherein Rn represents at least one embraces within its scope such changes and modi ?cations as fairly come within-the spirit of the appended claims. I claim: . I I oil-solubilizing alkyl group containing at least - 1. A lubricant composition comprising a major proportion of a‘. viscous hydrocarbon oil and an oil miscible metal salt of a substitutedthio acid of twenty carbon atoms. 8. A lubricant composition comprising a major proportion of a viscous hydrocarbon oil and an oil-miscible stannous salt of an acidic reaction phosphorus having the general formula 60 product obtained by reacting Pass with a, com pound having the formula? R. —— 0 ~ 1 1 P£SM Ra' in amounts sumcient to exert detergent and anti corrosive properties in the oil under heavy duty service, wherein ‘Rn represents at least one oil solubilizing alkyl group containing at least twenty carbon atoms and M represents the hydrogen equivalent of a metal. 65 in an amount suii‘icient to exert detergent and anti-corrosive properties in the oil under heavy duty service, wherein Rn represents at least one oil-solubilizing alkyl group containingv at least twenty carbon atoms. ' ' ,9. A lubricant composition comprising a major proportion of a viscous hydrocarbon oil and from about 0.01 per cent to about 5.0 per cent of an oil 2,410,050 7 miscible metal salt 01' a substitutedthio acid of I 'phosphorus having the general formula: Esq-o \/ Ego 8 ' ' 1 wherein Rn represents at least one oil-solubiiizing _alkyl group ‘containing at least twenty carbon atoms vand M represents the hydrogen equivalent 01a metal. . JOHN J. '