Polymerization of methacrylonitrile with potassium in ammonia

The polymerization of methacrylonitrile with potassium and potassium amide in liquid ammonia has been investigated. The results indicated that the degree of polymerization was approximately independent of the monomer and the catalyst concentrations. Furthermore, unlike lithium amide catalysts, potassium amide in ammonia initiates the polymerization of methacrylonitrile as rapidly as potassium does. The results with potassium amide catalysis were similar to those in potassium catalysis. When methacrylonitrile was reacted with potassium in ammonia, small amounts of isobutyronitrile could be detected in the reaction product. On the basis of these results, it is suggested that part of the initiator system in the methacrylonitrile—potassium—ammonia system is potassium amide produced in situ. This is similar to the styrene—potassium—ammonia system studied by Wooding and Higginson. The major termination reaction proposed is a transfer to monomer and to a small extent to the solvent ammonia. Methacrylonitrile was polymerized rapidly to a colorless polymer by initiation by potassium hydroxide. The reaction appears to be slower than that with potassium and potassium amide as catalysts and is retarded by trace amounts of water.