Hydrolysis of methylethoxydisilylmethanes

Abstract

AbstractHydrolysis of monomers of the type (I) should give polymers with the skeleton SiCSiO, which might possess better properties than siloxanes. The monomers were prepared by the action of methylmagnesium bromide on hexaethoxydisilylmethane. From mono‐ up to pentamethylethoxydisilylmethanes were obtained, the symmetrically substituted and even‐numbered methyl compounds being obtained in preferential yields.Hydrolysis of these five monomers gave interesting results. The strong tendency of ring formation reduced their functionality and thus gave less chance to form crosslinks. While pentamethylmonoethoxydisilylmethane gave the normal product (II), tetramethyldiethoxydisilylmethane gave a ring dimer (III), which, although closely analogous to cyclosiloxane D4, resisted all attempts at ring opening to give a linear polymer. The trifunctional trimethyl compound gave an oil of the type (IV), consisting of rings connected into a chain by oxygen atoms. Dimethyltetraethoxydisilylmethane, although tetrafunctional, gave, on hydrolysis, a highly crystalline compound with a cage structure (V). Only the pentafunctional monomer, monomethylpentaethoxydisilylmethane, gave an insoluble infusible powder of high stability.Co‐hydrolysis of the monomers gave fused ring compounds; dimethyltetraethoxydisilylmethane and tetramethyldiethoxydisilylmethane, when hydrolyzed together, gave a compound of formula (VI). magnified image