The copolymerization kinetics of ethylene oxide and propylene oxide in an atomizing-circulation reactor under semi-continuous operation is studied which is of great importance for molecular designation. The kinetic parameters are obtained by numerical optimization of the kinetic model. The copolymerization kinetics of ethylene oxide and propylene oxide in an atomizing-circulation reactor under semi-continuous operation is studied which is of great importance for molecular designation. The kinetic parameters are obtained by numerical optimization of the kinetic model.