Condensation of methylphenylalkoxysilanes in an active medium as a selective method for synthesis of cyclic or linear methylphenylsiloxanes

Polycondensation of methylphenyldialkoxysilane was studied under the conditions of an active medium, namely, an acetic acid excess, being simultaneously a reactant, catalyst, and solvent. This method was shown to be universal for the synthesis of a wide range of polymethylphenylsiloxanes of diverse structure. The conditions that allow one to synthesize both linear and cyclic methylphenylsiloxanes by this method were found. The possibility to prepare linear polymethylphenylsiloxanes with the molecular weight up to 34000 amu was shown.