Linear and cyclic organosiloxanes

Abstract

Organosilicon monomers containing functional groups at silicon atoms are extremely inclined to various reactions of transformation. At the present time, the most practically significant organosilicon polymers are industrially produced from organochlorosilanes of various functionalities. Application of partial hydrolytic condensation to synthesis of chlorine-containing alkyl- and arylsiloxanes is known since the old times. In the case if hydrolysis of dialkylchlorosilanes proceeds with water excess, complete replacement of chlorine atoms by hydroxyl groups and formation of dihydroxydiorganosilanes, which are easily condensed with water extraction, takes place already at the initial stage of the process. For the purpose of increasing selectivity of partial hydrolytic condensation of aralkyl (aryl) chlorosilanes, the vapor-phase method of polychlorosiloxanes production at high temperature in the absence of solvents has been suggested. Heterofunctional condensation reaction is more suitable for synthesizing organocyclosiloxanes with functional groups at silicon atoms.