Polymerization of acrylonitrile initiated by ceric ion–citric acid redox system

Heterogeneous polymerization of acrylonitrile initiated by ceric ammonium sulfate–citric acid (C.A.) redox system is reported at 35 ± 0.2°C under nitrogen atmosphere. The rate of monomer disappearance is found to be proportional to [C.A.]⁰, [Ce⁴⁺]^0.63, and [Monomer]^1.59. The rate of ceric ion disappearance is directly proportional to ceric ion concentration but independent of monomer concentration. The initial rate was independent of [H₂SO₄]. The molecular weight of polyacrylonitrile increases with increasing monomer concentration and decreasing ceric ion concentration. Activation energy was found to be 27.9 kJ/mol.