Patent GB-804119-A (GB)
Title: Improvements in polysiloxanes
IPC: C07F7/08
Filed: 1956-03-01
Abstract: A lubricant comprises one or more siloxanes having the average general formula <FORM:0804119/III/1> wherein m is 1, 2 or 3, n has an average value from 2 to 9, A is -CN or -COOR0, where R0 is cyclohexyl or an alkyl group of 1 to 18 C atoms, each R1 is H or an alkyl radical of 1 to 8 C atoms and each R is an alkyl radical of 1 to 5 C atoms (see Group IV (a)), with or without other lubricants in amount of 10 to 90 per cent by weight such as esters, e.g. butyl stearate, dodecyl pelargonate, dioctyl sebacate and dioctyl adipate or liquid hydrocarbons, corrosion inhibitors, e.g. phenothiazine, and lubricity-enhancing and wear-reducing agents, e.g. phosphoric acid, tricresyl-, triphenyl, tricyclohexyl or trioctyl-phosphate, phosphite or phosphonate.  In Example (7) the product of (4) was mixed with tricresyl phosphate with or without dioctyl sebacate.ALSO:Organopolysiloxanes useful as lubricants or hydraulic fluids and having the average general formula <FORM:0804119/IV (a)/1> wherein m is 1, 2 or 3, n has an average value from 2 to 9, A is -CN or -COOR0, where R0 is cyclohexyl or an alkyl group of 1 to 18 carbon atoms, each R1 is H or an alkyl radical of 1 to 8 carbon atoms, may be made by reacting (1) a siloxane of the formula <FORM:0804119/IV (a)/2> with (2) a compound of the formula <FORM:0804119/IV (a)/3> Compounds (2) specified are esters of lactic, glycollic, a  - hydroxybutyric, a  - hydroxy - isobutyric, a  - hydroxy - n - valeric, a  - hydroxy - isovaleric, b  - hydroxypropionic, b  - hydroxybutyric, g -hydroxybutyric and a -hydroxydecanoic acids, and glycollonitrile, ethylenecyanohydrin, lactonitrile and acetonecyanohydrin.  The reaction is generally effected by heating the reactants with stirring, compound (2) preferably being used in excess, until the theoretical amount of HCl is evolved, and this may require from 10 to 20 hours at 200 DEG  to 250 DEG  C.  Where the reaction is effected in a solvent such as benzene, toluene or xylene, in the presence of a tertiary amine, e.g. trimethylamine, triethylamine, pyridine and diethylaniline, temperatures from 0 DEG to 35 DEG  C. are used.  The resulting oils are isolated, by filtering off the hydrochloride salt of the amine, if used, and stripping to remove unreacted esters and solvent.  In examples, the compounds are made in the above manner from a ,o -dichloropolydimethyl or -polydiisopropyl siloxane and (1) methyl a -hydroxybutyrate or ethyl lactate; (2) n - butyl a  - hydroxybutyrate or butyl glycollate; (3) n - hexyl - a  - hydroxyisobutyrate, per se or in admixture with an equal quantity of t-octyl a -hydroxyisobutyrate, or cyclohexyl a -hydroxyisovalerate; (4) n-octyl a -hydroxybutyrate; (5) acetone-cyanohydrin, glycollonitrile, ethylenecyanohydrin, lactonitrile or 3,3,5 - trimethylhexaldehyde cyanohydrin; (6) n - octadecyl a  - hydroxyisobutyrate.  The compounds may be mixed with 10 to 90 per cent by weight of other lubricants, e.g. esters of alcohols from octyl to octadecyl with fatty acids of 4 to 18 C atoms or diesters of diacids of 6 to 12 C atoms with monohydric alcohols of 6 to 10 C atoms, e.g. butyl stearate, dodecyl pelargonate, dioctyl sebacate and dioctyl adipate, or liquid hydrocarbons.  Corrosion inhibitors, e.g. phenothiazine, lubricity-enhancing and wear-reducing agents such as phosphoric acid, triphenyl-, tricresyl-, tricyclohexyl- or trioctyl-phosphate, -phosphite or -phosphonate, may also be added. In Example (7), the product of (4) was mixed with tricresylphosphate with or without dioctyl sebacate.