GB799055A - New corrosion inhibitors and lubricating compositions containing the same - Google Patents

Abstract

The invention comprises the oil-soluble reaction product of a mercaptan RSH, formic acid and 2:5-dimercapto-1:3:4-thiadiazole in molar ratio from 1:1:1 to (3+x):(1+x):1, where x is 1-10, at 30-250 DEG F., R is a hydrocarbon radical of 1-30 carbon atoms. The products are believed to have one of the following structures <FORM:0799055/IV (b)/1> or <FORM:0799055/IV (b)/2> depending on the proportions of the reactants. The preferred proportions are 4 : 2 : 1 giving the second of the above structures. An acidic catalyst may be employed such as chlorine, hydrogen chloride, sulphuric acid or a metal chloride. Examples show the use of t-octyl and t-dodecyl mercaptans, these being in the preferred class of aliphatic mercaptans of 6-20 carbon atoms. Others specified are ethyl, butyl, hexyl, nonyl, octadecyl and phenyl mercaptans and it is also stated that R may be alkaryl. Phosphorus compounds.-Lubricating oil additives are made by reacting a phosphorus sulphide (e.g. P2S5) with a hydrocarbon at 200-500 DEG F., using 1-50 per cent (preferably 5-25 per cent) of the phosphorus sulphide. The product can then be treated with steam at 100-600 DEG F. The acidity of the product may be neutralized with an oxide, hydroxide, carbonate or sulphide of an alkali or alkaline earth metal, or with ammonia, an alkylamine or an arylamine. Heavy metal salts (e.g. Sn, Ti, Al, Cr, Co, Zn, Fe) can then be made by double decomposition. The hydrocarbon is preferably a polymer or copolymer, e.g. of propylene, butene or amylene, having a molecular weight of 150-50,000 (e.g. 500-10,000). A higher paraffin or olefine or condensation product thereof with an aromatic hydrocarbon may also be used, or an unalkylated aromatic. Suitable hydrocarbons are mentioned.ALSO:An oil composition comprises a major proportion of an oil and 0.02-10 per cent of the reaction product of a mercaptan RSH, formic acid and 2 : 5-dimercapto-1 : 3 : 4-thiadiazole in molar ratio from 1 : 1 : 1 to (3 + x) : (1 + x) : 1, where x is 1-10. R is a hydrocarbon radical of 1-30 carbon atoms and the product is believed to have one of the following structures: <PICT:0799055/III/1> The composition may also contain 0.002-10 per cent of P- and S-containing detergent and 0.001-10 per cent of a sulphurized terpene. The products of the above formula are corrosion inhibitors. Specified compounds are those in which R is t-octyl or t-dodecyl, and R may also be aryl or alkaryl. The phosphorus-containing constituent may be a neutralized phosphorus sulphide reaction product of a hydrocarbon, alcohol, ketone, ester, amine, alkylphenol turpentine, or stearonitrile. A hydrocarbon is preferred and suitable ones are mentioned, especially higher olefines, higher paraffins, aromatics and poly-olefines. The other constituent may be a sulphurized mineral oil, nondrying animal or vegetable oil, olefine or sperm oil instead of terpene as above. The oil may be a hydrocarbon (e.g. mineral oil or olefin polymer), alkylene oxide or polycarboxylic ester lubricant, or may be a fuel oil, non-drying animal or vegetable oil, or internal combustion engine fuel.