GB816237A - Improvements in or relating to corrosion resistant lubricant composition - Google Patents

Abstract

A lubricant composition comprises a major proportion of a lubricating oil containing elemental sulphur, a sulphur-containing organic compound or a mixture thereof and a minor proportion of the oil-soluble reaction product of 1 molar part of 2,5-dimercapto-1,3,4-thiadiazole and 1 to 3 molar parts of an unsaturated cyclic compound, having at least one olefinic double bond and of at least 6 carbon atoms. The lubricating oil may be a natural or synthetic hydrocarbon oil or a synthetic lubricating oil such as an alkylene oxide polymer or polycarboxylic acid ester. Sulphur - containing organic compounds include the reaction products of a phosphorus sulphide with a hydrocarbon, such as a mono-olefin hydrocarbon polymer or a wax-benzene, alcohol, ketone, amine, or ester, neutralized with a basic material such as an hydroxide, carbonate, oxide, or sulphide of an alkali or alkaline earth metal or ammonia or an amine. The cation may be replaced by a heavy metal, e.g. tin, titanium, aluminium, chromium, cobalt, zinc or iron by double decomposition. The reaction product of a phosphorus sulphide with a fatty acid ester, degras, alkylated phenol, turpentine or stearonitrile may also be used. Examples of cyclic olefinic compounds which may be reacted with 2,5-dimercapto-1,3,4-thiadiazole are styrene, alpha-methyl styrene, pinene, dipentene, vinyl thiophene, vinyl pyridine, cyclohexene, methyl cyclohexene, terpinene, terpinolene, sylvestrene, bornylene, and methyl cyclopentene. The composition may also contain conventional additives. Examples comprise a solvent extracted SAE30 oil, a barium-containing neutralized reaction product of P2S5 and polybutene, and the reaction product of 2,5-dimercapto - 1,3,4 - thiadiazole and dipentene, pinene, styrene, or alpha-methyl styrene.ALSO:Oil-soluble 1,3,4-thiadiazole derivatives are prepared by reacting 2,5-dimercapto-1,3,4-thiadiazole with an unsaturated cyclic compound having at least one olefinic double bond and at least 6 carbon atoms, at a temperature of 25-150 DEG C., the reagents being used in molar proportions of thiadiazole to unsaturated compound of from 1 : 3 to 1 : 1. If desired, catalysts such as ultra-violet light, organic peroxides and azonitriles may be used. Specified unsaturated reagents are styrene, a -methyl styrene, pinene, dipentene, vinyl thiophene, vinyl pyridine, cyclohexene, methyl cyclohexene, terpinene, terpinolene, sylvestrene, bornylene and methyl cyclopentene. The reaction may result in addition of one or each mercapto group of the thiadiazole to the double bonds of one or two molecules respectively of the unsaturated reagent; short reaction times are suggested as favouring 1 : 1 addition products. The products are used as corrosioninhibiting lubricant additives (see Group III). In examples: (1) commercial dipentene is heated with the dimercaptan at 100-120 DEG C. and the reacted mixture is worked up, yielding an oil containing 7.47 per cent N and 26.6 per cent S; (2) pinene yields a similar product containing 7.55 per cent N and 26.6 per cent S; (3) a -methyl styrene yields a product containing 8.53 per cent N and 27.3 per cent S; and (4) styrene yields a product containing 10.66 per cent N and 36.6 per cent S. Phosphosulphurized hydrocarbons. - Other lubricant additives mentioned (see Group III) include: (a) the reaction products of a phosphorus sulphide and an aromatic or alkylated aromatic hydrocarbon, e.g. benzene, naphthalene, toluene, xylene, diphenyl and waxbenzenes; (b) phosphosulphurized hydrocarbons neutralized with a basic compound, e.g. potassium, sodium, calcium or barium hydroxide, potassium or sodium carbonate, calcium or barium oxide, sodium sulphide, ammonia, or an alkyl or aryl amine. Neutralized products containing a heavy metal, e.g. Sn, Ti, Al, Cr, Co, Zn or Fe can be obtained by reacting the products of (b) with a salt of the heavy metal.