Deoligomerization of cyclooligosiloxanes with dimethyl carbonate over solid-base catalysts

Cyclooligosiloxanes, hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane and decamethylcyclopentasiloxane were efficiently deoligomerized with dimethyl carbonate using an alumina-supported potassium fluoride catalyst under a continuous vapor-phase flow condition to form dimethoxydimethylsilane monomer. In the deoligomerization of larger cyclooligosiloxanes, the catalyst was deactivated. The addition of a small amount of methanol suppressed the deactivation. These results strongly suggest a new method for recycling silicone via monomers.