Thermal decomposition behavior of mono‐aminimides and their application to polymerization of epoxide

Mono‐aminimide compounds [N,N‐dimethyl‐N‐(2‐hydroxypropyl)‐amine‐N′‐propionimide (1), trimethylamine valerimide (2), and trimethylamine benzimide (3)] were found to exhibit different thermal decomposition behaviors and polymerization efficiencies for an epoxide (phenyl glycidyl ether, PGE). The thermal decomposition rate of aminimides at 150°C decreased in the order 1 > 2 > 3. It seemed that hydrogen bonding enchanced the decomposition rate, and the resonance effect induced by the phenyl group suppressed the decomposition. 1 was thermolyzed to give isocyanate and tertiary aminoalcohol, which subsequently reacted with each other to give isocyanate and tertiary aminoalcohol, which subsequently reacted with each other to give urethane. When 2 was heatted, the isocyanurate generated from 2 remained intact. On heating of 3, we observed the formation of triphenyl isocyanurate. PGE reacted with those aminimides and gave different products depending on their thermolyzed products. Equimolar mixtures of isocyanate, tertiary amine, PGE were used in the model reactions, and the thermal reaction between the expected decompostion products of aminimides was investigated in the presence and absence of PGE. The rate of PGE consumption was in the order PGE + 2 > PGE + 1 > PGE + 3. It is clear that the formation of urethanes and oxazolidone derivatives affects the polymerization process.