Alkyl-methyl silicates prepn. - by reacting silicon with methanol-alkanol mixt. in the presence of alkali metal alcoholate

摘要

New alkyl silicate mixts. are of formula (RO)n(CH3O)4-n Si (I) (where R are Et, Pr, iso-Pr or butyl and n = 0.8-3.8). (I) are prepd. by reaction of pulverulent Si, in pure or combined form, the amt. of Si being >=30 wt. %, with a mixt. of 8-80 wt.% MeOH and 92-20 wt.% of the alcohol ROH at atmos. press. and at >100 degrees C in the presence of an alkali metal alcoholate and pref. an aromatic hydrocarbon of b.pt. >190 degrees C and m.pt 40 degrees C in an amt. of 31-95 wt. % based on the amt. of liq. reaction medium. Used for prodn. of silica by pptn. or combustion, as binders in smelting, in prodn. of paints and Zn-rich coatings, as reticulants in organosilicon hardeners of elastomers at room temp. and as starting materials for organosilicon resins. The process uses waste material from the prodn. of Me or Ph chlorosilanes.