Improvements in or relating to the preparation of phenyl silane diols

摘要

1,134,488. Preparation of diphenyl silane diols. M. & T. CHEMICALS Inc. 29 March, 1967 [29 March, 1966], No. 14353/67. Heading C3S. Diphenyl silane diols are prepared by reacting #MgX with # a SiX b in the presence of an inert hydrocarbon solvent, wherein # is a phenyl group which may be inertly substituted, (a+b) = 4 and a is 0 or 1, the #MgX being in a solution-complex with a cyclic ether and in a molar ratio of (b - 2) moles of #MgX per mole of # a SiX b , and the product obtained, # SiX b , is then hydrolysed, preferably after distilling off a quantity of the complexing cyclic ether, to precipitate the diphenyl silane diol. Typical compounds of the # a SiX b type are silicon tetrachloride and tetrabromide and phenyl trichlorosilane and tribromosilane. Typical complexing agents are tetrahydrofuran, 2-methyl tetrahydrofuran, tetrahydropyran, 2-ethoxytetrahydropyran, N-methylmorpholine dihydropyran and tetrahydrofurfuryl ethyl ether. The preferred Grignard reagents are phenyl magnesium chloride and substituted phenyl magnesium chlorides. The preferred hydrocarbon solvents have a boiling range of 100-150‹ C. The exothermic reaction is maintained between 25‹ and 125‹ C. and the distillation at 85- 125‹ C. for 30-180 mins. generally removes 25-70% of the complexing agent leaving a reduced reaction mixture containing 1À5 to 3 moles of complexing agent per mole of magnesium added as the Grignard reagent. The hydrolysis is effected by adjusting the pH to between 6 and 7, using a buffer solution, preferred buffers being sodium or potassium bicarbonate, at 0-45‹ C. for 30-120 mins. and the precipitated product yields 80-95% of pure diphenyl silane diol. Reference has been directed by the Comptroller to Specification 795,772.