The kinetics of phase-transfer catalyzed free-radical polymerization of acrylonitrile (AN) was carried out with water-soluble initiator peroxomonosulphate (PMS) with phase-transfer catalysts (tetrabutylammonium chloride and benzyltributylammonium chloride (TBAC and BTBAC) in toluene/water two-phase systems in the temperature range of 45-55-degrees-C at fixed pH (4) and ionic strength. The rates of polymerization (R(p)) were evaluated at various values of [ PMS ], [ PTC ], and [ AN ]. It has been observed that the rates of polymerization increase with an increase of [ AN ], [ PMS ], and [ PTC ]. A kinetic scheme has been proposed to account for the experimental observations.