Patent GB-687418-A (GB)
Title: Improvements in or relating to lubricating oil additives
Filed: 1950-03-07
Abstract: The Specification comprises as a new chemical product valuable as a lubricating oil additive (see Group III) an alkali or alkaline earth metal, zinc, magnesium, or aluminium salt of a phosphorus sulphide treated sulphurized cyclic terpene, said phosphorus sulphide treatment being conducted at elevated temperature.  The terpene is preferably a monocyclic C10H16 terpene, e.g. dipentene and its isomers.  Any of the phosphorus sulphides, e.g. P2S5 or P4S3, may be used for treating the sulphurized terpene.  The product is then treated with the appropriate metal base, the preferred metal bases being those of barium, calcium, sodium, potassium and lithium.  In the sulphurization step one mole. of the terpene may be treated with 1 to 3 moles. of elemental sulphur at between 135 DEG  and 220 DEG C. and in the phosphorus sulphide treatment from 0.01 to 0.5 moles. of phosphorus sulphide may be used for each mole. of sulphurized terpene.  Preferably the sulphurized terpene is diluted with an inert diluent such as mineral lubricating oil and the phosphorus sulphide then added and the mixture heated at 110-175 DEG  C.  A small quantity of a higher alcohol may then be added as a plasticizer.  In examples: (1) "Special Dipentene" (a mixture of dipentene and terpinolene) containing a small amount of a -pinene, a -terpineol, D -2,4(8)-para-menthadiene and para-cymene) is added to molten sulphur and the mixture heated at 165-170 DEG  C. (example 1) and 165-175 DEG C. (example 2).  The product is then diluted with mineral lubricating oil and added to P4S3 and the mixture heated at 125-150 DEG  C.  A commercial alcohol derived from coconut oil is then added as plasticizer and the mixture further heated and finally stripped of volatile constituents.  The product is then heated to 125 DEG  C. and barium hydroxide octahydrate added slowly.  The product is then maintained at 125 DEG  to 150 DEG  C. for one hour and then blown with nitrogen gas at the same temperature and filtered to yield a product containing sulphur, phosphorus and barium. Specification 679,296 is referred to.ALSO:A lubricating composition comprises a major proportion by weight of lubricating oil and a minor proportion by weight sufficient to substantially inhibit corrosion by said oil of copper lead bearings, of an alkali or alkaline earth metal, zinc, magnesium or aluminium salt of a phosphorus sulphide treated sulphurized cyclic terpene (see Group IV (b)), said phosphorus sulphide treatment being effected at elevated temperature.  The terpene is preferably a monocyclic C10H14 terpene, e.g. dipentene and its isomers and any phosphorus sulphide, e.g. P2S5 and P4S3 may be used for treating the sulphurized terpene and the product is converted to the metal salt by treating with the metal base. Generally from 0.01 per cent to 5 per cent of the salt may be used as lubricating additive based upon the weight of the total composition, or the salt may be provided in the form of an oil concentrate containing an amount of the additive of up to 50 per cent of the weight of the oil.  In examples the barium salt of P4S3 treated sulphurized "Special Dipentene" (a mixture of dipentene and terpinolene containing a small amount of a-pinene, a-terpineol, D  2, 4 (8) para menthadiene and para cymene) is blended in a mineral lubricating oil and the blend subjected to tests for determining the effectiveness of the barium salt as a lubricant additive. Tests for the effectiveness of the P4S3 treated sulphurized terpene products as lubricating additives are also given, the results showing that the barium salt shows substantial improvement both as an oxidation inhibitor and as a copper corrosion inhibitor.  Specification 679,296 is referred to.