SYNTHESIS OF ORGANOSILOXANES WITH REACTIVE GROUPS AT SILICON ATOMS

The heterofunctional condensation of (dihydroxy)organodisiloxanes and -trisiloxanes with vinyl(hydro)organodichlorosilanes was studied with the purpose of preparing alpha,omega-dichloroorganosiloxanes with reac tive Si-H and Si-CH=CH2 groups. During the isolation, 1,9-dichloro-1,9 -dihydropentamethyloctasiloxane disproportionates with the elimination of (dichloro)methylsilane to form heptamethylcyclotetrasiloxane. A se ries of cyclotetra-, cyclohexa-, and cyclooctasiloxanes with Si-H and Si-CH=CH2 groups was obtained by the condensation of alpha,omega-dihyd roxyorganosiloxanes with a,omega-(dichloro)divinyl(dihydro)organosilox anes.