Catalytic reactivity of organometallic compounds in olefin polymerization. VI. Vinyl polymerization by metal ketyl

Some metal ketyls (mono‐alkali metal complex of non‐enolizable ketone) were found to induce the polymerization of vinyl compounds such as acrylonitrile and methylmethacrylate. Styrene was not polymerized by the ketyls. On the other hand, the di‐alkali metal complex of the ketone had a greater activity than the ketyl. By the dimetal complex. styrene was also polymerized readily to a quantitative yield, even at low temperature. In the polymerization of styrene, the formation of living polymer was observed. A study on the copolymerization by the ketyl or the dimetal complex showed the polymerization to be anionic. Variation in the kind of ketone and metal component of the ketyl or the kind of solvent, appreciably affected the catalytic activity of the ketyl. No effect of solvent, however, was found on the copolymer composition. Some samples of polymethyl methacrylate obtained by ketyl or dimetal complex were proved to have the same infrared absorption spectrum as that of the type‐F crystallizable polymer. Consideration was made on the possible mechanism of the polymerization.