GB705266A - Gear lubricant - Google Patents

Abstract

Reaction products of chlorinated aliphatic hydrocarbons with thiocarbonates are obtained by reacting a polychlorinated aliphatic hydrocarbon with an alkali or alkaline earth metal salt of an alkyl or aralkyl thiocarbonic acid under such conditions that only part, preferably about one third, of the chlorine is replaced by the alkyl or aralkyl thiocarbonate group. The aliphatic hydrocarbon may contain 2 to 24 carbon atoms, preferably 5 to 15; petroleum naphtha or kerosene of B.P. 150 DEG -275 DEG C. is preferred. The chlorination may be carried to the point at which the chlorine content is from 40 to 60 per cent. A mono-, di- or trithiocarbonate radical may be caused to replace part of the chlorine, the dithiocarbonate (xanthate) being preferred. Preferably the alkyl group of the thiocarbonate group contains 5 carbon atoms or less. Suitable compounds include sodium and potassium methyl, ethyl, propyl, isopropyl, benzyl, butyl and amyl xanthates and the corresponding mono- or tri-thiocarbonates. The reaction product may contain from about 25 to 40 per cent. chlorine and from about 7 to 15 per cent. sulphur. The reaction is preferably carried out in the presence of a solvent, such as acetone or methyl ethyl ketone, which is a non-solvent for the alkali chloride formed. In an example petroleum naphtha (Stoddard solvent) is chlorinated until it contains 54 per cent. of chlorine. The chlorinated naphtha is dissolved in acetone, potassium ethyl xanthate is added (in an amount to give the desired chlorine: sulphur ratio) and the mixture is refluxed with stirring. When reaction is complete, the mixture is filtered and acetone distilled off. Dihydroabietyl malate is prepared bv reacting 2 mols. of hydroabietyl alcohol with 1 mol. of dl-malic acid. The commercial hydroabietyl alcohol may be used. Water produced during the reaction may be removed as an azeotrope with benzene. Alkyl phenol-phosphorus pentoxide reaction products. Preferred alkyl phenols for this reaction are mono-tertiary octyl phenol and di-tertiary amyl phenol: di-secondary amyl phenol, cetyl phenol, octadecyl phenol and wax phenol may also be used. Three mols. of the phenol are heated with 1 mol. of phosphorus pentoxide at 75 DEG -125 DEG C. for several hours. Several examples are given in the Specification. The three materials are incorporated in mineral lubricating oil to give an extreme pressure lubricating composition (see Group III).ALSO:An extreme-pressure lubricating composition comprises a mineral lubricating oil having incorporated therein (a) 1 to 10 per cent. of a product obtained by substituting a part of the chlorine in a chlorinated aliphatic hydrocarbon by a thiocarbonate group, (b) 0.1 to 3 per cent. of dihydroabietyl malate and (c) 0.1 to 1.5 per cent. of the reaction product of an alkylated phenol and phosphorus pentoxide, all percentages being based on the total composition. Preferred amounts of the additives are 5 per cent. of (a), 1 per cent. of (b) and 0.5 per cent. of (c). The chlorinated aliphatic hydrocarbon-thiocarbonate reaction product (for preparation see Group IV (b)) may be a polychlor compound in which about one third of the chlorine is replaced by an alkyl or aralkyl thiocarbonate group. The chlorine content of the chlorinated hydrocarbon may be between about 40 and 60 per cent. Preferably the hydrocarbon is one containing from 5 to 15 carbon atoms, though compounds containing 2 to 24 carbon atoms may be used. Petroleum naphtha (or kerosene) of BP 150 DEG -275 DEG C. is preferred. A mono-, di- or tri-thiocarbonate radical may be caused to replace part of the chlorine, the dithiocarbonate (xanthate) being preferred. Suitable compounds for the substitution (used as their sodium or potassium salts) include methyl, ethyl, propyl, isopropyl, benzyl, butyl and amyl xanthic acids and the corresponding mono- and tri-thiocarbonic acids. The use of alkyl thiocarbonic acids in which the alkyl group contains more than 5 carbon atoms is not advantageous. The reaction product may contain from about 25 to 40 per cent. chlorine and from about 7 to 15 per cent. sulphur. The dihydroabietyl malate may be prepared from commercial hydroabietyl alcohol and dl-malic acid (see Group IV (b)). Preferred alkylated phenols which may be reacted with phosphorus pentoxide to obtain additive (c) are mono-tertiary octyl phenol and di-tertiary amyl phenol: di-secondary amyl phenol, cetyl phenol, octadecyl phenol and wax phenol may also be used (see Group IV (b)). A specified composition comprises 5 per cent. by weight of a reaction product of chlorinated kerosene and potassium ethyl xanthate, 1 per cent. dihydroabietyl malate, 0.5 per cent. of a reaction product of ditertiary amyl phenol and phosphorus pentoxide, and 93.5 per cent. of SAE 90 grade mineral oil.