Patent GB-658182-A (GB)
Title: Improvements in or relating to lubricating compositions and the preparation of additives therefor
Inventor: EVANS ELLIOTT ALFRED
IPC: C10M137/10
Filed: 1947-12-09
Abstract: Oil-soluble metal salts of organic di-substituted dithiophosphoric acids, derived at least in part from saturated aliphatic hydroxyethers or from heterocyclic alcohols containing only oxygen and carbon in the heterocyclic nucleus, are used as ingredients of lubricating compositions (see Group III).  The metal salts may have the general formula <FORM:0658182/IV (b)/1> where n represents the valency of the metal M, R1 is a saturated aliphatic radicle containing an ether group or a heterocyclic radicle containing only oxygen and carbon in the heterocyclic nucleus, and R2 is any suitable organic nucleus.  The radicle R1 may be derived from aliphatic hydroxy-ethers such as ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, triethylene glycol monobutyl ether or 3-methoxy-n-butanol or from a heterocyclic alcohol such as tetrahydrofurfuryl alcohol.  The radicle R2 may be derived from aliphatic alcohols such as amyl, octyl, lauryl or cetyl alcohols, alicyclic alcohols such as cyclohexanol or methyl cyclohexanol, phenols, especially alkylated phenols such as octyl cresol p-octyl phenol, p-tert. amyl phenol or tert.-butyl cresol, aromatic alcohols such as benzyl alcohol, or aliphatic hydroxy-ethers such as those already mentioned.  The metal salts may be salts of barium, calcium, strontium, magnesium, zinc, aluminium, nickel, cobalt, tin, cadmium, chromium, manganese or thallium.  Preparation of the metal salt of the di-substituted dithiophosphoric acid may be effected by first reacting the aliphatic hydroxyether or heterocyclic alcohol with phosphorus pentasulphide, and where a mixed organic dithiophosphate is desired an appropriate hydroxylic organic compound may be admixed with the hydroxyether or heterocyclic alcohol for simultaneous reaction with the phosphorus pentasulphide.  The acid may be neutralized with caustic soda and a desired metal salt produced by the addition of a suitable salt of the metal.  Alternatively the acid may be neutralized directly with the oxide or hydroxide of the desired metal.  In the examples: (1) a mixture of tetrahydrofurfuryl alcohol and octyl cresol is reacted with phosphorus pentasulphide, the acid obtained is neutralized with caustic soda and the sodium salt is converted to the chromium salt of tetrahydrofurfuryl octylcresyl dithiophosphoric acid by addition of chrome alum; (2) ethylene glycol mono-n-butyl ether is reacted with phosphorus pentasulphide, the acid obtained is neutralized with caustic soda and the sodium salt is converted to the zinc salt of di - (b  - butoxyethyl) - dithiophosphoric acid by addition of zinc chloride; the cadmium salt is obtained by using cadmium chloride instead of zinc chloride, and (3) a mixture of 2-ethyl-n-hexanol and 3-methoxy-n-butanol is reacted with phosphorus pentasulphide and the acid obtained is neutralized with zinc oxide to give the zinc salt of 3-methoxy-n-butyl 2-ethyl-hexyl dithiophosphoric acid. Specifications 569,939, [Group III], and 658,183 are referred to.ALSO:A lubricating composition comprises a mineral lubricating oil and a minor proportion of an oil-soluble metal salt of an organic di-substituted dithiophosphoric acid derived at least in part from a saturated aliphatic hydroxy-ether or from a heterocyclic alcohol containing only oxygen and carbon in the heterocyclic nucleus.  The metal salt may have the general formula <FORM:0658182/III/1> where n represents the valency of the metal M, R1 is a saturated aliphatic radicle containing an ether group or a heterocyclic radicle containing only oxygen and carbon in the heterocyclic nucleus, and R2 is any suitable organic nucleus.  The metal salt inhibits oil oxidation and bearing corrosion, substantially reduces the deposition of gum, lacquer and carbon on hot metal surfaces, and increases the film strength of the oil.  The lubricating composition is particularly suitable for use as the lubricant in high-speed Diesel engines.  The radicle R1 may be derived from aliphatic hydroxy-ethers such as ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, triethylene glycol monobutyl ether or 3-methoxy-n-butanol or from a heterocyclic alcohol such as tetrahydrofurfuryl alcohol.  The radicle R2 may be derived from aliphatic alcohols such as amyl, octyl, lauryl or cetyl alcohols, alicyclic alcohols such as cyclohexanol or methyl cyclohexanol, phenols, especially alkylated phenols such as octyl cresol, p-octyl phenol, p-tert.-amyl phenol or tert.-butyl cresol, aromatic alcohols such as benzyl alcohol, or aliphatic hydroxy ethers such as those already mentioned.  Specific examples of di-substituted dithiophosphoric acids are tetrahydrofurfuryl octyl-cresyl dithiophosphoric acid, di-(b -butoxyethyl) dithiophosphoric acid, 3 - methoxy - n - butyl 2 - ethyl - hexyl dithiophosphoric acid and ethylene glycol monoethyl ether lauryl dithiophosphoric acid. The metal salts may be salts of barium, calcium, strontium, magnesium, zinc, aluminium, nickel, cobalt, tin, cadmium, chromium, manganese or thallium.  Especially where a chromium salt of a di-substituted dithiophosphoric acid, the zinc salt of di-(21-butoxy-2-ethoxyethyl) dithiophosphoric acid, the calcium salt of di-(b -butoxyethyl) dithiophosphoric acid or the cobalt salt of 21-methoxy-2-ethoxyethyl methyl cyclohexyl dithiophosphoric acid is employed, the lubricating composition may also contain a metal salt of a petroleum sulphonic acid.  This sulphonate may be a salt of one of the metals already listed or other polyvalent metal, but tin sulphonates are preferred.  In the examples, mineral lubricating oil compositions are described containing (1) chromium tetrahydrofurfuryl octyl cresyl dithiophosphate and tin petroleum sulphonate; (2) zinc or manganese 3 - methoxy - n - butyl 2 - ethyl - n - hexyl-dithiophosphate; (3) cobalt 21-methoxy-2-ethoxyethyl methyl cyclohexyl dithiophosphate and cadmium petroleum sulphonate; (4) tin di - (b  - n - butoxyethyl) dithiophosphate; (5) zinc di-b -n-butoxyethyl) dithiophosphate with or without calcium or tin petroleum sulphonate; (6) nickel or aluminium b -ethoxyethyl lauryl dithiophosphate; (7) zinc di-(3-methoxy - n - butyl) dithiophosphate and calcium petroleum sulphonate; (8) cadmium di - (b  - n - butoxyethyl) dithiophosphate and barium petroleum sulphonate; (9) magnesium di - (21 - n - butoxy - 2 - ethoxyethyl) dithiophosphate and nickel petroleum sulphonate; (10) zinc di-(a -methyl-isoamyl) dithiophosphate; (11) zinc di-(2-ethyl-n-hexyl) dithiophosphate; (12) nickel di-(methyl cyclohexyl) dithiophosphate; (13) barium b -n-butoxyethyl nonyl dithiophosphate; (14) barium di-(decyl and dodecyl) dithiophosphate; (15) zinc di-(21-n-butoxy - 2 - ethoxyethyl) dithiophosphate and chromium petroleum sulphonate. Specifications 567,939 and 658,183 are referred to.