Patent GB-862199-A (GB)
Title: Thia-alkyl ortho-silicate esters
Inventor: GARNER PHILIP JAMES
IPC: C07F7/04
Filed: 1959-04-10
Abstract: The invention comprises thia-orthosilicates of the formula (RO)4-nSi(OR1)n where n is 1, 2, 3 or 4, R1 is a thia-alkyl group and R is an alkyl group, each having at least 4 carbon atoms and in which at least one of the carbon atoms attached to an oxygen atom is a tertiary carbon atom. They are prepared by reacting the appropriate alkanol and thioalkanol, together or successively, with a silicon tetrahalide in the presence of a hydrogen halide acceptor.  The reaction may be effected in an inert liquid.  The Specification lists a number of compounds according to the invention, and in the examples: SiCl4 is added to a solution of 1,1-dimethyl-3-thiaheptanol and pyridine in petroleum naphtha, followed by 2-ethyl hexanol, the temperature being kept not higher than 30 DEG  C.  After refluxing, di-(2 - ethylhexyl) - di - (1,1 - dimethyl - 3 - thiaheptyl) orthosilicate is separated; (2) SiCl4 is first reacted with tert.-butyl alcohol and then with 3-thiaheptanol to give di-(3-thiaheptyl)-di-(tert.-butyl) orthosilicate.  The compounds are useful as hydraulic fluids alone or mixed with other mineral or synthetic lubricants, as lubricating oils.  Examples of synthetic oils are polyoxyalkylenes, polysiloxanes and polymers of unsaturated hydrocarbons.  Among the compositions specified are: (a) and (b) the liquid block copolymer of ethylene oxide and propylene oxide described in Example 2 of Specification 786,950, a coester of sebacic acid, 2-ethyl hexanol and 3,5,5-trimethyl hexanol, phenothiazine and the orthosilicate of Example 1 above, the two compositions including different amounts of the silicate.  The compositions may also contain other additives, e.g. an epoxy compound and a metal salt of phenolaldehyde condensate, as described in Specification 745,161, an epoxy compound and an arylamine as described in Specification 759,284, or a bis-(amino-arylalkane) and a thio-di-arylamine as described in Specification 740,575.ALSO:A lubricating oil comprises a thia-alkyl orthosilicate of the formula (RO)4-nSi(OR1)n, where n is 1 to 4, R1 is a thia-alkyl group and R is an alkyl group, each having at least 4 carbon atoms and in which at least one of the carbon atoms attached to an oxygen atom is a tertiary carbon atom, the silicates being used alone or blended with a mineral or synthetic lubricating oil.  Examples of synthetic oils are dialkyl esters of dicarboxylic acids, polyoxyalkylenes, polysiloxanes and polymers of unsaturated hydrocarbons.  Specified compositions are: (A) and (B) the liquid block copolymer of ethylene oxide and propylene oxide described in Example 2 of Specification 786,950, a coester of sebacic acid, 2-ethyl hexanol and 3,5,5-trimethyl hexanol, phenothiazine and di-(2 - ethylhexyl) di-(1,1 - dimethyl - 3 - thiaheptyl) orthosilicate, the two compositions including different amounts of the silicate; (c) di-(3,5,5-trimethylhexyl) sebacate and the same silicate as in (A) or (B).  Other additives may be added to the compositions, e.g. an epoxy compound and a metal salt of phenolaldehyde condensate as described in Specification 745,161, an epoxy compound and an arylamine as described in Specification 759,284, or a bis-(aminoaryl-alkane) and a thio-di-arylamine as described in Specification 740,575.