Patent GB-700530-A (GB)
Title: Dithiophosphatosuccinic acid triester salts and lubricating oil compositions containing the same
IPC: C10M137/10
Filed: 1951-07-30
Abstract: The invention comprises dithiophosphatosuccinic acid triester salts of formula:-  <FORM:0700530/IV(b)/1> including the isomeric forms thereof, in which R is an aliphatic or cycloaliphatic hydrocarbon radicle, R1 and R2 are aromatic, aliphatic, or cycloaliphatic radicles, M is a salt-forming radicle and x is the valency of M. They may be made by condensing an O, O-diester of dithiophosphoric acid containing the radicles R1 and R2, with a monoester of formula ROOC CH = CH COO H or an isomer thereof, and neutralizing the product with a salt-forming base containing the radicle M.  The condensation proceeds at temperatures up to 100 DEG C. or higher and is usually completed within about 5 to 24 hours.  A small excess of diester is usually used.  Inorganic and organic bases may be used and those specified include ethylamine, aniline, xylidene and toluidene. Alkali and alkali earth metal salts are specified and zinc, lead, aluminium, cadmium, tin and bismuth salts.  Salts of alkali metals and ammonium are made by neutralization with an aqueous alcoholic solution of the hydroxide.  Salts of calcium, barium, strontium and magnesium are made by neutralizing and boiling with a suspension of the metal oxide or hydroxide in a relatively large quantity of a polar solvent, e.g. a lower aliphatic alcohol, containing about 1/10 th of its volume of a non-polar solvent such as benzene or toluene. Polyvalent metal salts are made by double decomposition of the alkali metal salts with the chloride or sulphate of the polyvalent metal in solvents such as ethanol.  Many radicles are specified for R1 and R2 representative being methyl, butyl, cyclohexyl, octyl, octadecyl, phenyl, naphthyl, chlorphenyl and bromphenyl.  Maleic and fumaric acid esters specified include the methyl and isobutyl esters. Representative of other specified esters are n - butyl, n - hexyl and n - octadecyl maleate and esters derived from alcohols obtained from the hydrogenation of carbon oxides or as by-products in the production of higher aliphatic-ketones and esters of cycloaliphatic alcohols such as cyclohexanol and butyl cyclohexanols obtained by reducing phenols or naphthenic acid petroleum esters.  Esters of maleic acid are preferred.  The products are lubricating oil additives.  In examples (1) O, O - di (4 - methyl - pentyl - 2) dithiophosphoric acid is treated with mono - 3, 5, 5 - trimethyl hexyl maleate and the product with barium oxide in methanol-benzene mixture to yield the barium salt or with sodium hydroxide in aqueous ethanol to give the sodium salt which on treatment with zinc chloride yields the corresponding zinc salt, (2) O, O - di - octadecyl dithio - phosphoric acid is treated with monoethyl maleate and the product with barium methoxide in methanol-benzene, (3) the dithioacid of (1) is treated with mono-octadecyl maleate and the product converted to the barium, sodium and zinc salts as in (1), (4) O, O - dimethyl dithiophosphoric acid is treated with mono - n - octadecyl maleate and the product converted to the barium salt, (5) O, O - di-decyl dithiophosphoric acid is treated with mono-(4 - methylpentyl - 2) maleate and the product converted to the barium salt, (6) O, O - di - p - tertiaryamylphenyl dithiophosphoric acid is treated with mono-p-tertiarybutylcyclohexyl maleate and the barium salt of the product formed, (7) O, O - di - p - octylphenyl dithiophosphoric acid and mono-4-methylpentyl - 2 - maleate are reacted and the barium salt of the product formed, (8) O, O - di - 2, 4 - diamyl phenoxyethyl dithiophosphate is treated with-monoethyl maleate and the barium salt formed as before, (9) O, O - dihydroabietyl dithiophosphate and monoethyl maleate are reacted and the barium salt of the product formed, (10)O, O-di-sec. butyl dithiophosphoric acid is treated with mono - 3, 5, 5 - trimethylhexyl maleate and the barium and ammonium salts of the product formed, (11) O, O - di - isopropyl - dithiophosphoric acid is treated with mono - p - tert. butylcyclohexyl maleate and the barium salt of the product formed, (12) O, O, di-4 - methylpentyl - 2 - dithiophosphoric acid is treated with mono-tridecyl maleate and the barium salt of the product formed (13) the acidic product of (10) is converted to the sodium salt and the latter to the zinc, lead and mercuric salts and to the guanidinium, phenylbiguanide and dodecylamine salts, (16) O, O - diethyldithiophosphoric acid is treated with mono - 2 - ethylhexyl maleate and the product converted to the barium salt and (17) O, O - di - 4 - methylpentyl - 2 - dithiophosphoric acid is treated with mono - 4 - methylpentyl - 2 - maleate and the product converted to the barium salt.ALSO:Hydrocarbon lubricating oil compositions comprise a compound of formula <FORM:0700530/III/1> where R is an aliphatic or cycloaliphatic hydrocarbon radicle, R1 and R2 are aromatic, aliphatic or cycloaliphatic radicles, M is a salt-forming radicle and x is the valency of M. Inorganic and organic bases may provide the radicle M and those specified include ethylamine, aniline, xylidine and toluidine. Ammonium, alkali and alkali earth metal salts are mentioned and zinc, lead, aluminium, cadmium, tin and bismuth salts specified. The amine salts are antioxidants for use in oils at relatively low temperatures, e.g. in turbine oils and anti-rust compositions when also it is preferred that R1 and R2 are lower alkyl groups; and the polyvalent metal salts are used in oils for internal combustion engines.  Many radicles are specified for R1 and R2 representative being methyl, butyl, cyclohexyl, octyl, octadecyl, phenyl, naphthyl, chlorophenyl and bromphenyl.  It is preferred that ROOC CH CH2COO-be derived from maleic rather than fumaric acid esters and representative of values for R are methyl, isobutyl, n-butyl, n-hexyl and n-octadecyl, alkyl residues from alcohols obtained by the hydrogenation of carbon oxides or as by-products in the production of higher aliphatic ketones and of esters of cycloaliphatic alcohols such as cyclohexanol and butyl cyclohexanols obtained by reducing phenols or naphthenic acid petroleum esters.  The additives are preferably used in small amounts e.g. about 0.1-4 or 5 per cent.  The additives are compatible with conventional detergents, stabilisers and sludge-inhibitors and may be used with aliphatic or aromatic sulphonates such as calcium petroleum sulphonate, alkyl phenol sulphides such as p-p1-dibutyl, diamyl-or dioctyl phenol mono-or polysulphides and their metal salts, or salts of oxygen- or sulphur - containing phosphorus acids.  These additives are normally used in amounts of about 0.1-5 per cent., e.g. 0.5-2 per cent., in admixture with the compounds of the invention.  In examples the antioxidant effect of incorporating 0.2 per cent. of the following additives in a refined mineral lubricating oil containing 10 p.p.m. of copper as copper naphthenate is illustrated in (14) with zinc 3, 5, 5-trimethyl hexyl (di-4-methylpentyl - 2 dithiophosphato)-, octadecyl di-4-methyl-pentyl-2-dithiophosphato) and 3, 5, 5-trimethylhexyl (di-sec. butyl dithiophosphato)-succinate, barium ethyl (di-octadecyl dithiophosphato)-, n-octadecyl (di-methyl-dithiophosphato)-, 4-methylpentyl-2-(di-n-decyl dithiophosphato)-, 4-tert. butyl-cyclohexyl (di-p-amylphenyl dithiophosphato)-, 4-methylpentyl-2-(di-p-octylphenyl dithiophosphato)-, ethyl (di-2, 4-diamyl phenoxeythyl dithiophosphato)-, ethyl (di-hydroabietyl dithiophosphato)-, p-tert. butyl-cyclohexyl (di-isopropyl dithiophosphato)- and tridecyl (di-4-methylpentyl-2-dithioposphato)-succinate, and ammonium 3, 5, 5-trimethylhexyl (di-sec. butyl dithiophosphato) succinate, and in (15) together with corrosion tests with barium octadecyl (di-hexyl dithiophosphato) - succinate (also in white mineral oil without the copper compound); in (16) antioxidant tests are carried out in a mineral lubricating oil containing 10 p.p.m. of copper and 0.076 per cent., 0.13 per cent. and 0.2 per cent. of barium 2-ethylhexyl (diethyl dithiophosphato) succinate; in (17) corrosion tests are shown with a mineral lubricating oil containing 0.625 per cent. of barium-4-methylpentyl (di-4-methylpentyl)-2-dithiophosphato)-succinate and in (18) antioxidant and corrosion tests are shown on a mineral lubricating oil containing 0.04 per cent. of Fe as an iron naphthenate catalyst and 0.5 of zinc tridecyl (dihexyl dithiophosphato) succinate.