Patent GB-596570-A (GB)
Title: Improvements in or relating to lubricating oil compositions
IPC: C10M141/10
Filed: 1944-05-17
Abstract: A lubricating oil composition particularly suitable for use under heavy duty, high temperature conditions in the crankcase of an internal combustion engine contains a salt of a dithiophosphoric acid diester with a metal from Groups II, III or IV of the Periodic Table and a salt of a 2.4-dialkyl phenol sulphide with one of the said metals.  Suitable metal salts of dithiophosphoric acid diesters are those derived from dialkyl dithiophosphoric diesters in which each alkyl group contains at least 5 carbon atoms whether the alkyl groups are straight chain or branched chain primary or secondary alkyl groups, dithiophosphoric diesters of cycloaliphatic alchols such as dicyclohexyl dithiophosphate, and diaryl dithiophosphates especially those in which the aryl groups contain aliphatic sidechains as substituents.  Specific metal salts of dithiophosphoric acid diesters are the calcium, barium, zinc and tin salts of dicapryl, di-n-octyl, dilauryl, dioctadecyl, di (p-tert-amylphenyl), di (2, 4-diamylphenyl), or di-(dodecylphenyl) dithiophosphates and esters of dithiophosphoric acid with at least one branched-chain higher alkyl radicle such as those obtained by the reaction of phosphorus pentasulphide with mixtures of branched-chain alcohols obtained as by-products in the commercial hydrogenation of oxides of carbon such as the "B-22," "B-23," "B-24" and "B-30" fractions.  The metal salts of 2, 4-dialkyl phenol sulphides are compounds of the general formula:- <FORM:0596570/III/1> in which R, R1, R2 and R3 are alkyl groups, n is 1 or 2, M is a metal from Groups II, III or IV of the Periodic Table and V is the valency of the metal.  The alkyl groups may be like or unlike but preferably one or more of these groups contains from 5 to 21 carbon atoms.  Specific metal salts of 2, 4-dialkyl phenol sulphides are the calcium barium zinc and tin salts of 2, 4-diamylphenol monosulphide and they may be prepared by the method described in Specification 561,801.  In the examples, mineral lubricating oil compositions are described which contain (1) barium di (2, 4- diamylphenol) monosulphide and one of (a) a mixture of barium dilauryl dithiophosphate, barium diamyl dithiophosphate and barium "B-24" alcohol dithiophosphate, (b) barium di-dodecylphenyl dithiophosphate, (c) the calcium or zinc salts of dicycloalkyl dithiophosphoric acid diesters derived from a mixture of cycloparaffinic alcohols of 15-18 carbon atoms, (d) calcium salts of dialkyl dithiophosphoric acid diesters derived from a mixture of octadecanol and woolgrease or (e) barium di (ethylhexyl) dithiophosphate and (2) barium di (2, 4-diamyl phenol) disulphide and calcium (triisobutylphenyl) dithiophosphate.  Specification 575,828 also is referred to.  Preparation of zinc salts of dicycloalkyl dithiophosphoric acid diesters.  A mixture of cycloparaffinic alcohols of 15-18 carbon atoms is reacted with phosphorus pentasulphide and the resulting dithiophosphoric acid diesters are neutralized with zinc oxide.ALSO:The preparation of the following lubricating oil additives is described: (1) calcium, salts of dicycloalkyl dithiophosphoric acid diesters; a mixture of cycloparaffinic alcohols of 15-18 carbon atoms is reacted with phosphorus pentasulphide and the resulting dithiophosphoric acid diesters are neutralized with calcium oxide; (2) calcium salts of dialkyldithiophosphoric acid diesters; a mixture of octadecanol and wool grease is reacted with phosphorus pentasulphide and the resulting dithiophosphoric acid diesters are neutralized with calcium oxide; and (3) barium di-(2,4-diamylphenol) disulphide; 2,4-diamylphenol is reacted with sulphur monochloride and the product is neutralized with barium hydroxide.