Polymerization of acrylonitrile initiated by Ce(IV)-sucrose redox system: A kinetic study

摘要

The polymerization of acrylonitrile (M), initiated by the free radicals formed in situ in the Ce(IV)-sucrose redox system, was studied in aqueous sulfuric acid medium under nitrogen atmosphere in the temperature range of 30-60 degrees C. The rate of polymerization is proportional to [M],(1.0) [R],(0.76) [Ce(IV)](0.8), and [H+](-0.46). The rate of Ceric ion disappearance and the rate of polymerization R-p have been measured. The effects of some water-miscible organic solvents, surfactants, ionic strength, 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 Ce(IV)-sucrose complex formation, which generates free radicals, is suggested. The chain termination step of the polymerization reaction was determined. (C) 2008 Wiley Periodicals, Inc.