Electro-Epoxidation\nof Propylene in the Gas Phase\nwith Solid-Polymer-Electrolyte Water Electrolysis

The development of a reaction system for direct epoxidation\nof\npropylene is an essential topic. Gas-phase electro-epoxidation of\npropylene to propylene oxide (PO) with water as the oxidant was successfully\naccomplished by using solid-polymer-electrolyte (SPE) electrolysis\nwithout solvents. The oxidized surface of the PtOx anode was essential\nfor propylene epoxidation and oxidation. It was revealed that PO was\nsequentially oxidized and accumulated on the anode by the interval\nelectrolysis experiment. The formation rate and Faraday efficiency\n(FE) to PO were improved by applying mild hot-press conditions for\nthe SPE unit because the active phase of the oxide surface of PtOx\nwas maintained and diffusibility of water in the SPE (Nafion) membrane\nwas improved. The FEs to PO are low in this work, but this system\nis halogen-free.