The Synthesis of the Polymer Containing the Si-O-phenylene Bond, using Transition Metal Salts as Catalysts

Various transition metals were found to be effective as catalysts in the dehydrocondensation of phenols and silanes. R3SiH+PhOH salt→R3SiOPh+H2 The effective species were PdCl2, H2PtCl6·6H2O, PtCl2, RhCl3, NiCl2, silane-treated NiCl2, Ptl2, PtS, Raney Ni, Pd-black, Pt-black, Au-black, FeCl3, ZnCl2, CuSO4, CuCl, Cu–Cr, Cu(CH3CO2)·CuO, the methyl ethyl ketoxime complex of Pd, Pt(OX)3, and Pd(OX)2. The ineffective species were metal mirrors of Pd, Au, Ag, Pt, and Cu, and the acetylacetonato complex of Ni, Co(II), Co(III), and Cu. The reaction was then extended to the preparation of polymers containing a Si–O–phenylene linkage in the main chain. Dihydricphenols, e.g., bisphenol A, hydroquinone, 4,4′-dihydroxydiphenyl gave high-molecular-weight polymers with an equimolar amount of a dihydro-silane, e.g., diphenylsilane, p-toluylmethylsilane and p-bisdimethylsilylphenylene, in bulk or in a solvent at temperatures above 150°C. The polymer obtained began to flow above 100°C.