Anionic Polymerization of Aldehydes

VII. Polymerization of Aldehydes with Alkali-Metal Ketyls

Abstract

Polymerization of aldehydes with alkali-metal ketyls as catalyst was studied. Lithium, sodium and potassium were used as alkali metals and benzophenone, Michler's ketone and benzyl were used as ketones. High polymer yield was obtained when the polymerization was carried out at -78°C with lithium complexes. When sodium complex was used as catalyst, polymer yield at-78°C was lower than that at-100°C. Only low polymer yield was obtained as potassium complex was used as catalyst. Block copolymerization of acetaldehyde was attempted by using living polymers which obtained by polymerization of vinyl momomers with these complexes as catalyst. It was possible to polymerize n-, iso-butyraldehyde and chloral with these complexes. In the polymerization of aldehyde with these complexes, it is considered from the infrared spectra of low molecular weight polymer that alcohlate anion of metal ketyl participates in initiation of the polymerization. Effects of metallic and organic components of complexes on the polymerization of acetaldehyde were also discussed.