Protection of hydroxy-gps. using hexa:methyl:di-silazane - by reaction in presence of cation exchanger and small amts. of water

摘要

Prepn. of hydrocarbons contg. C-OSiMe3 units comprises reaction of aliphatic- or aromatic-bound C-OH gps. with hexamethyl disilazane in the presence of an acid catalyst (e.g. a cation exchanger), opt. with introduction of a carrier gas and with addition of moisture. The water content in the reaction mixt. over the whole reaction is 0.001-2 wt.%. The water content is pref. 0.01-0.5 wt.% and the water is added via the reagents, the catalyst or the gas. Polyoxyalkylene glycols may be silylated. USE/ADVANTAGE - The prods. are used as intermediates (protecting the OH gp.) in the organic chemical and pharmaceutical industries. The process gives good yields in short reaction times and does not require exclusion of moisture. Sepn. of prod. from catalyst is simple