Polymerization of acrylonitrile initiated by the manganese (III)–glycine redox system: a kinetic study

The polymerization of acrylonitrile, initiated by the free radicals formed in situ in the manganese (III)–glycine redox system, was studied in aqueous sulfuric acid medium in the temperature range of 40–55°C. The rate of polymerization (Rp) and the rate of manganese (III) disappearance have been measured. The effects of some water-miscible organic solvents, surfactants, and complexing agents on the rate of polymerization were investigated. The temperature dependence of the rate was studied and the activation parameters were computed using the Arrhenius and Eyring plots. A mechanism consistent with the experimental data, involving manganese (III)–glycine complex formation, which generates free radicals, is suggested. The chain termination step of the polymerization reaction is by mutual interaction of the free radicals.