Polymerization of α‐piperidone by alkali metal and certain acyl compounds

Abstract

Abstract It has been shown that the resonance‐stabilized, six‐membered lactam, α‐piperidone, is polymerized by alkali metal and acyl compounds to form poly‐5‐valeramide, melting point 259°C., [ r ] = 0.25, d = 1.243. A mechanism is proposed for the polymerization of α‐piperidone with alkali metal and acyl compound which involves chain propagation by the stepwise addition of piperidone ring at the end of the molecules leading to the formation of poly‐5‐valeramide. This mechanism is supported by experimental results obtained in the presence of alkali metal salts of α‐piperidone, data on deuterium exchange reactions, and infrared analytical evidence. The conditions for polymerization have carefully been investigated. A maximum conversion of 76% was obtained. As the concentration of alkali metal and acyl compound increases, the conversion increases. On the other hand, the conversion decreases when the concentration of alkali exceeds 3.0 mole‐% and the concentration of N ‐acetyl piperidone is over 1.0 mole‐%. As the reaction temperature increases, both conversion and the degree of polymerization diminish. Furthermore, the polymerization with other useful catalysts has been reported.