Patent GB-714509-A (GB)
Title: Improvements relating to sulphurized terpene esters of dithiophosphoric acid and lubricating compositions containing the same
IPC: C07F9/173
Filed: 1951-08-21
Abstract: The invention comprises S-(sulphurized terpene) o,o-dialkyldithiophosphates of formula <FORM:0714509/IV (b)/1> in which T is the residue of a sulphurized terpene hydrocarbon and each R is an aliphatic radicle of 1-18 carbon atoms per molecule, a cycloaliphatic radicle of from 6 to 10 or more carbon atoms per molecule or a phenyl or alkylphenyl radicle of 6-22 carbon atoms per molecule.  They may be made by condensing 1 to 2 mols. of a terpene hydrocarbon with 1 mol. of a sulphur halide, heating the product to 110-160 DEG  C. to expel about 25-50 per cent of its combined halogen, mixing the product so obtained with a salt of an o,o-dithiophosphoric acid diester containing the groups OR and heating the mixture until the sulphurized terpene ester is obtained. The condensation may be effected at 25-100 DEG  C., a range of 25-50 DEG  C. being preferred.  The dehalogenation is preferably effected between 110-120 DEG  C. and 150-160 DEG  C. so that the heat-treated sulphurized terpenes contain from 1 to about 1.5 mols. of combined halogen per mol.  Treatment with salts of o,o-dithiophosphoric acid diester is usually carried out in the presence of a solvent for the salt, preferably a polar solvent such as water or an aliphatic monohydric alcohol, many of which are specified, at temperatures of about 25-100 DEG  C. or up to about 120-130 DEG  C. when a refluxing solvent is present.  Other solvents, e.g. toluene, solvent naphtha or hydrocarbon lubricating oil may also be present.  Any ratio of dithiophosphoric acid ester salt may be added to the halogenated sulphurized terpene quantities mentioned being 0.1-0.2 mols. or up to an equimolar amount. Inorganic alkalies, e.g. alkali metal hydroxides, carbonates and ammonium hydroxide are preferably present during this reaction, the preferred pH being 7.0-8.5.  Alkali or alkaline earth metal, ammonium and zinc salts may be used, as may those of aliphatic amines and pyridine.  Terpenes mentioned include limonenes, dipentene, terpinenes, sabinanes, caranes, pinanes, camphanes, fenchene and bornylene.  Commercial mixtures of terpenes are preferred starting materials.  The product, used as a lubricating oil additive (see Group III) is preferably washed with hot aqueous alkali, e.g. sodium carbonate, solution and stripped by heating under vacuo, e.g. at 90-125 DEG  C. at 20-25 mm.  In examples a mixture of terpenes consisting mainly of dipentene with some beta-pinene, alpha-pinene and cymene is treated with SCI2 and the dehydrohalogenated product in aqueous sodium carbonate with the sodium salts of (1) and (5) di - (4 - methyl - 2 - pentyl) - and (2) diisopropyl-dithiophosphoric acid, in (3) betapinene is treated with SC12, the product dehydrohalogenated and treated in aqueous sodium carbonate with the sodium salt of di-(4-methyl-2-pentyl)-dithiophosphoric acid; (4) alpha-pinene is treated with SC12, the product dehydrohalogenated and treated in sodium hydroxide with di-(4-methyl-2-pentyl)-dithiophosphoric acid; (6) dipentene is treated with SC12, the product dehydrohalogenated and treated with an aqueous solution of the salt of di - (4 - methyl - 2 - pentyl) - dithiophosphoric acid; (7) dipentene is treated with SC12, the product dehydrohalogenated and treated in aqueous sodium carbonate with a reaction product of cetyl alcohol and P2S5 neutralized with potassium hydroxide; (8) dipentene is treated with SC12, the product dehydrohalogenated and treated with a reaction product of 1,1,3,3-tetra-methylbutyl phenol and P2S5 neutralized with sodium hydroxide; and in (9) beta-pinene is treated with SC12, the product dehydrohalogenated and treated with an aqueous solution of calcium diisopropyl dithiophosphate in the presence of lime. Specification 575,828 is referred to.ALSO:A lubricating composition comprises a major amount of a hydrocarbon lubricating oil and a minor quantity of a sulphurized terpene ester of formula <FORM:0714509/III/1> where R is an aliphatic radicle of 1-18 carbon atoms per molecule, a cycloaliphatic radicle of 6-10 or more carbon atoms per molecule or a phenyl or alkylphenyl radicle of 6-22 carbon atoms per molecule and T is the residue of a sulphurized terpene hydrocarbon.  Terpenes mentioned include limonenes, dipentene, terpinenes, sabinanes, caranes pinanes, camphanes, fenchene and borrylene.  Commercial mixtures of terpenes are preferred.  The additives may be used in amounts of 0.1-5 per cent. by weight of lubricating oil and concentrates containing 40-50 per cent. by weight of additive may be prepared.  The esters are made by reacting the terpene with SCI2, dehydrohalogenating the product and treating it with a salt of the appropriate dithiophosphoric acid (see Group IV (b)).  Examples are provided showing the antioxidative and anti-corrosive properties in hydrocarbon lubricating oils of additives derived from a mixture of terpenes consisting mainly of dipentene with some beta-pinene, alpha-pinene and cymene and 1 and 5 di-(4-methyl-2-pentyl)- and 2 diisopropyl-dithiophosphoric acid and 3 beta-pinene, 4 alpha-pinene and 6 dipentene and di-(4-methyl-2-pentyl)-dithiophosphoric acid.  Specification 575,828 is referred to.