Polymerization of acrylonitrile: Kinetics of the reaction initiated by the Fe²⁺/BrO₃⁻ redox system

Abstract

SynopsisThe aqueous polymerization of acrylonitrile initiated by the bromate-ferrous redox system in aqueous sulfuric acid was studied under nitrogen atmosphere. The rate of polymerization increased with increasing concentration of ferrous in the range of 0.25-1 X 10-2M. The percentage of conversion increased with increasing concentration of the catalyst, but beyond 2.5 X 10-3M there was a decreasing trend in the rate of polymerization. The rate varied linearly with [monomer]. The initial rate of polymerization as well as the maximum conversion increased within the range of 1-2.5 X 10-3M KBr03, but beyond 2.5 X 10-3M the rate of polymerization decreased. The initial rate and limiting conversion increased with increasing polymerization temperature in the range 30-40OC; beyond 4OoC they decreased. The effect of certain neutral salts, water-miscible solvents, complexing agents, and copper sulfate concentration on the rate of polymerization was investigated. polymerization. It was therefore thought desirable to use the ferrous-bromate redox pair to examine its role in acrylonitrile polymerization.