Polymerization of tert‐butyl crotonate

Lithium alkyls and phenylmagnesium bromide, in toluene, and lithium‐naphthalene, in dimethoxyethane, polymerize tert‐butyl crotonate. Sodium naphthalene produces only low polymer (Mn <3000), and potassium naphthalene gives no polymer. Even lithium naphthalene, which polymerized tert‐butyl crotonate readily, fails to polymerize tert‐butyl tiglate. Free radicals polymerize neither tert‐butyl crotonate nor tert‐butyl tiglate. Poly(tert‐butyl crotonate) formed in the presence of lithium naphthalene is noncrystalline, in the presence of lithium alkyls, either noncrystalline or partly crystalline, and in the presence of phenylmagnesium bromide, highly crystalline. Poly(crotonic acid) was prepared from poly(tert‐butyl crotonate).