Synthesis and polymerization of epoxymethacrylates, 1. Catalysis and kinetics of the addition reaction of methacrylic acid and 2,2‐bis[4‐(2,3‐epoxypropoxy)phenyl]propane

Abstract

AbstractThe kinetics of the addition reaction of methacrylic acid (1) and 2,2‐bis[4‐(2,3‐epoxypropoxy)‐phenyl]propane catalyzed by tertiary aliphatic amines, aromatic N‐heterocycles and quaternary ammonium salts, respectively, was studied in bulk with equimolar amounts of functional groups from room temperature to 120°C. A reaction order of 1,5 with regard to the conversion of epoxy as well as carboxylic groups was observed. This can be explained assuming the formation of an ammonium alkoxide ion pair by the equilibrium reaction of an epoxy group with ammonium carboxylate and the irreversible consecutive reaction of the ion pair with (1) under formation of 2‐hydroxyester groups and regeneration of ammonium carboxylate. The reaction rate constants increase linearly with the concentration of the catalyst and increase with increasing basicity of alkylpyridines. The advantage of the aromatic N‐heterocyclic catalysts consists in their stability to peroxides which are ingredients of preparations together with the epoxy methacrylate Bis‐GMA, e. g. in dental composites and adhesives.