Extreme pressure lubricant composition

An extreme pressure lubricant comprises a lubricating oil from 3 to 10 per cent by weight of a phosphosulphurized hydrocarbon and a halogen- and sulphur-containing hydrocarbon, the phosphosulphurized hydrocarbon being present in a greater proportion than the halogen- and sulphur-containing hydrocarbon. The phosphosulphurized hydrocarbon may be prepared by reacting P2S3, P2S5, P4S3 or P4S7 with paraffins, olefins, olefin polymers, diolifins, acetylenes, aromatics or alkyl aromatics, cyclic aliphatics, petroleum fractions such as lubricating oil fractions, petroleums, waxes, cracked cycle stocks, condensation products of petroleum fractions and solvent extracts of petroleum fractions. Specified monoolefins are isobutylene, decene, dodecene, cetene octadecene, cerotene, melene, gasoline, olefinic extracts from gasoline, cracked waxes, dehydrohalogenated chlorinated waxes; polymers of monolefins may also be used. In addition, aromatic hydrocarbonic such as benzene, naphthalene, anthracene, toluene, xylene, diphenyl, and alkyl substituted aromatics, or resin-like oils of high molecular weight may be used. The reaction product may be obtained by heating the phosphorus sulphide with the hydrocarbon to a temperature of 300-550 DEG F. in a non-oxidizing temperature such as an atmosphere of nitrogen. The product may be refined by blowing with steam, alcohols or phenols at a temperature of 200-600 DEG F. The sulphur- and halogen-containing organic compound may be a halo-hydrocarbon sulphide such as a mono-or di- or polysulphide. Aromatic derivatives such as the chlorinated and brominated alkaryl sulphides are preferred, although sulphochlorinated hydrocarbons such as those formed by treating olefins, paraffins, and naphthalenes with sulphur halides may be used. Specified compounds are chloroparaffin wax polysulphide, dibromodiphenyl disulphide, dichlorodibenzyl sulphide, and chlorodimethylbenzyl disulphide. The oil may be a mineral oil, which may have been refined, with acid, alkali or solvent extraction treatment, or an animal, vegetable or fish oil, which may be hydrogenated; or a synthetic oil of the ester, polyester or polyether such as di - 2 - ethyl - hexyl sebacate, dibasic acid esters and polyalkyllene oxides. Stability may be increased by adding a soluble metal petroleum sulphonate such as that of lithium, sodium, potassium, calcium, strontium, or barium; and a metal alkyl phenol sulphide which may be that of calcium, barium, strontium or magnesium. The pref