Synthesis of propylene oxide in a paired electrolytic system: Studies on the mechanism and operating factors

Epoxidation of propylene to propylene oxide (PO) by means of paired electro lysis was studied in a bubbling system. An electrolytic cell, divided by an anion exchange membrane, was designed for producing PO in both anode and c athode compartments simultaneously. In the anode compartment, AgNO3 in the anolyte was used to form redox mediator, Ag+/AgO+, for indirect epoxidation of propylene. In the cathode compartment, oxygen was introduced into an ac idic aqueous catholyte to form H2O2, hydrogen peroxide, which further epoxi ded propylene. The examined factors, which affected the amount of PO produc tion per unit faraday, were the applied current, gas flow rate, electrolyte concentration and temperature. The optimum operating conditions of the ano de and the cathode compartments were obtained. The overall amount of PO pro duction per unit of energy consumption was evaluated, and a mechanism of pa ired electro-epoxidation of propylene is also proposed.