3,290,245 United States Patent Office Patiented Dec. 6, 1966 2 3,290,245 amounts of the amine and ammonium tungstate in the LUBRICATING COMPOSITONS CONTAINING presence of aqueous ammonia under reflux while passing AMNETUNGSTATES a stream of nitrogen through the reaction mixture until Joha Scotchford Eliott and Eric Descamp Edwards, the reaction is substantially complete, distilling water London, England, assignors to Castro Limited, a 5 and ammonia from the mixture and finally drying the British company product by blowing nitrogen through it at a tempera No Drawing. Fied June 3, 1960, Ser. No. 33,658 ture of about 100° C. Claims priority, application Great Britaia, Jane 5, 1959, The invention also includes lubricating compositions 19,370/59; Apr. 14, 1960, 13,454/60 comprising a major proportion of a lubricating oil and 11. Claims. (C. 252-32.7) a minor proportion, e.g. from 0.5 to 10% by weight on The invention relates to lubricating oil additives and O the weight of the composition, of a salt soluble in the lubricating compositions containing such additives. lubricating oil of molybdic or tungstic acid and the above According to the present invention there is provided a defined amines. salt of a molybdic acid or tungstic acid and an amine The production of organic nitrogen base molybdates having the formula: and tungstates which are soluble in hydrocarbon oils has proved to be an extremely difficult matter. Thus we have found that whereas the molybdates and tungstates R-(-NH, of the present invention are freely miscible with hydro l, carbon oils and are comparatively stable substances, the wherein R1 and R2 are the same or different straight 20 corresponding compounds derived from other nitrogen chain alkyl radicals having up to 4 carbon atoms in the bases, e.g. high molecular weight primary and secondary radical and R is an alkyl radical, the radicals R, R1 and straight chain amines and even the N-methyl and N,N- R being such that the total number of carbon atoms dimethyl derivatives of Primene JM-T, are oil-insoluble in the amine is from 16 to 50. Preferably the radicals substances which appear to have a complex structure 25 or alternatively to be highly unstable. R1 and R are both methyl radicals, and the total num We have also found that even when molybdates of ber of carbon atoms in the amine is from 18 to 22. tertiary alkyl primary amines are prepared, a certain Specific examples of the new salts are: minimum number of carbon atoms is necessary to ensure Primene JM-T molybdate adequate oil-solubility. Thus, for example, molybdates Primene JM-T paramolybdate 30 prepared from the closely related commercially available Primene JM-T tungstate amine Primene 81-R have been found to be but sparingly t-Octadecylamine molybdate soluble in hydrocarbon oils. In this instance, R and R2 t-eicosylamine molybdate are methyl radicals and R represents a mixture of t-Octadecylamine tungstate branched-chain alkyl radicals containing principally from 1-methyl-1-ethyl octadecylamine molybdate 35 9 to 11 carbon atoms. 1,1-dimethyl octadecylamine molybdate Lubricating compositions containing a lubricating oil 1-methyl-1-butyl hexadecylamine molybdate and a proportion of the Salt of the above-defined amines t-Triacontylamine molybdate and a molybdic or tungstic acid, may contain a wide range of proportions of the salt depending upon the Preferred salts are those of Primene JM-T, a com 40 particular application of the lubricating composition. mercially available material consisting essentially of a However, in compositions where this new lubricant addi mixture of tertiary alkyl primary amines having the above tive is employed as a cold sludge dispersant, the additive formula, where R1 and R2 are methyl radicals and R may be present in amounts of from 0.2 to 5 percent and represents a mixture of branched-chain alkyl radicals preferably from 0.4 to 2 percent by weight on the weight ' containing principally from 15 to 19 carbon atoms. In of the composition. general, for use as additives for lubricating oil composi According to the present invention there is also pro tions, salts of molybdic acid are preferred. vided a lubricating composition comprising a major pro By the fractional distillation of Primene JM-T under portion of a mineral oil of lubricating viscosity and a reduced pressure, cuts boiling over a narrow range can minor proportion of a combination of two additives, the be obtained containing amines or mixtures of isomeric 50 first additive being a salt of molybdic acid or tungstic amines having a definite neutral equivalent, correspond acid and above-defined amines and the second additive ing, for example, to t-octadecylamine and t-eicosylamine. being elementary Sulphur or an organic compound solu The salt of a molybdic acid and tungstic acid may ble in the lubricating oil containing divalent sulphur and be made by heating the amine and molybdic acid or capable of decomposing at temperatures produced local ammonium tungstate in the presence of water to form the ly by friction under boundary lubricating conditions at salt and subsequently removing excess water and isolat metal Surfaces to cause the formation of a friction re ing the salt. The molybdic acid and the ammonium ducing molybdenum or tungsten compound. tungstate may, of course, be formed in the reaction mix The Sulphur containing compound is preferably a zinc ture. When the salt is a molybdate it is preferably made dialkyl dithiophosphate which may have alkyl groups by heating equivalent amounts of the amine and molybdic 60 having a total number of carbon atoms in the alkyl groups acid at a temperature between 50° C. and 80° C. in of from 6 to 36. However, examples of other classes the presence of water, the mixture being stirred to dis which may be employed as the second additive are: solve the molybdic acid. The salt may be isolated by solvent extraction from the mixture and removing the Organic disulphides, and organic polysulphides, such as solvent by evaporation. The Salt may be prepared 65 tri-sulphides directly in a mineral oil by heating equivalent amounts Organic Xanthates and thiocarbonates of the amine dissolved in a mineral oil and molybdic Organic thiocarbamates e.g. dithiocarbamates acid at a temperature between 50° C. and 80° C. in Organic thiocyanates the presence of water, the mixture being stirred to dis Organic thioureas solve the molybdic acid and subsequently removing water 70 Furthermore, the organic sulphur-containing com from the product to form the salt dissolved in the oil. pound may be one of various sulphurised materials, such Tungstates are preferably prepared by heating equivalent as Sulphurised fatty oils or sulphurised terpenes. 3,290,245 3. 4. Preferred types of the second additive are the oil-solu A particular preferred composition in accordance with ble metal salts of organic dithiophosphoric acids e.g. zinc the invention is a lubricating composition comprising a or barium dialkyl dithiophosphates. These additives, major proportion of a mineral oil of lubricating viscosity the use of which in lubricating oils has been well known and a molybdate of an amine having the formula: for many years, confer valuable oxidation and corrosion 5 resistance to the oils in which they are dissolved and also enhance the load-carrying capacity. Other types of com pounds containing both sulphur and phosphorus may be employed, if desired, e.g. derivatives of organic thiophos phoric, thiophosphorous, thiophosphonic and thiophos where R is an alkyl radical having from 15 to 19 carbon phinic acids. Also, phosphorised sulphurised terpenes or O atoms, the molybdate being present in an amount to pro other unsaturated compounds may be used. Specific ex vide a molybdenum content of from 0.01 to 0.1 percent amples of these compounds are: by weight, a zinc dialkyl dithiophosphate having a total of from 6 to 24 carbon atoms in the alkyl radicals present Zinc dihexyl dithiophosphate (zinc di(4-methyl-2-pentyl) in an amount to provide from 0.1 to 0.2 percent by weight dithiophosphate) 15 of sulphur in the composition, and from 0.5 to 3.0 per Zinc dihexyl/diisopropyl mixed dithiophosphate cent by weight of a basic alkaline earth metal petroleum Zinc dicapryl dithiophosphate sulphonate derived from a petroleum sulphonic acid hav Barium dilauryl dithiophosphate ing a molecular weight of from 400 to 600, the weights Tributyl thionophosphate being based upon the total weight of the composition. Triphenyl phosphine sulphide 20 The new compounds of the present invention are Ethylenebis (dihexyl dithiophosphate) of particular utility in lubricating oils for internal com Dihexyl dithiophosphate disulphide ibustion engines, both petrol and diesel engines, and have 2-ethyl hexyl diphenyl dithiophosphinate valuable sludge dispersing properties. They are particul PAS3-treated turpentine larly effective dispersants of the so-called "cold sludge' Zinc dilauryl dithiophosphate 25 which tends to form in certain types of engine in cold Phosphorized sulphurized sperm oil weather. This form of sludge, which is produced as Dibenzyl disulphide the result of the ingress of water and fuel combustion Dibenzyl trisulphide products into the crankcase oil, is a particular problem Phosphorized sulphurized o-pinene in engines which are operated intermittently for short Dilauryl trisulphide 30 periods or more continuously at only a fraction of their Di-n-butyl trithiodiacetate maximum power output. It may appear on pistons and Benzyl thiocyanate around piston rings as resinous deposits resulting in re Zinc di-n-butyl dithiocarbamate duced efficiency of the engine, or it may appear as a Sulphurized sperm oil stiff emulsion in the sump or on the timing cover. n-Butyl dimethyldithiocarbamyl acetate 35 It has previously been proposed to use colloidal disper The two additives may be employed in the composi sions of molybdenum disulphide in lubricating oils in tions in a wide range of proportions depending on the order to reduce friction and in cutting and metal work application of the lubricating composition.