Selective oxidation of methanol to dimethoxymethane over iron and vanadate modified phosphotungstate

Abstract

Iron and vanadate modified phosphotungstate was fabricated by Fe salt and vanadate incorporating into H3PW12O40. Its morphology, composition and structure were determined by XRD, SEM, TEM, FT-IR and XPS. The catalytic performance of the prepared composite for selective oxidation of methanol to dimethoxymethane using molecular oxygen as oxidant was evaluated. A detail study on influence of key reaction parameters, involving the calcination temperature of the catalyst during the preparation, reaction time, temperature and pressure, and flow rate of O2, methanol and N2 on the reactivity and selectivity was optimized. The results showed that the composite was active and highly selective for methanol oxidation, giving ca. 70% conversion of methanol and > 96% selectivity to DMM. The adsorption behaviour of methanol on surface of the catalyst or various components composed of the catalyst was investigated by in situ DRIFTS technique to identify the active sites and further considering reaction mechanism. Moreover, the operating lifetime and stability of the catalyst was also discussed.