Copolymerization of propylene and complexed acrylonitrile by TiCl3–AlEt3 catalyst system

Abstract It was found that an equimolar complex is formed from acrylonitrile with triethylaluminum. The complex formation was verified by infrared spectroscopy. The original bands of acrylonitrile at 2235 cm−1 shifted and the new bands appeared at 2225 and 2275 cm−1. Copolymerization of acrylonitrile with propylene was proved to be possible with a TiCl3–AlEt3 catalyst system. Kinetic studies on copolymerization of propylene with acrylonitrile showed that composition of the starting monomer mixture markedly influenced the course of the reaction and the acrylonitrile content of the copolymer. Optimum conditions of the copolymerization reaction were as follows: temperature, 70°C; reaction time, 30 min; molar ratios of acrylonitrile to the metal alkyl and Al to Ti, 1:1 and 2;1, respectively, concentration of the total amount of monomers. Conversion is influenced by the aging time of the acrylonitrile‐metal alkyl complex; the yield is a linear function of the aging time. Composition of copolymers was determined by chemical analysis.