Selective formation of 1,5-disodiumoxyhexamethyltrisiloxane in the reaction of dimethylsiloxanes and sodium hydroxide

摘要

The 1,5-disodiumoxyhexamethyltrisiloxane has been isolated in high yield with a purity of up to 98%, by simple interaction of dimethylsiloxanes with sodium hydroxide. The reasons of high selectivity of the reaction towards 1,5-disodiumoxyhexamethyltrisiloxane were analyzed. It was found that variation of reaction time, type of dimethylsiloxane precursor and ratio between sodium hydroxide and dimethylsiloxanes in wide range led to the materialization of most part of used sodium hydroxide in 1,5-disodiumoxyhexamethyltrisiloxane. Its fast crystallization and precipitation from the homogeneous reaction media were found to be the main reason of the high selectivity of the reaction towards 1,5-disodiumoxyhexamethyltrisiloxane. The crystalline structure of 1,5-disodiumoxyhexamethyltrisiloxane was determined and its packaging peculiarities were discussed and illustrated. (C) 2019 Elsevier B.V. All rights reserved.