One-pot synthesis of ethylene glycol by oxidative hydration of ethylene with hydrogen peroxide over titanosilicate catalysts

Abstract

The oxidative hydration of ethylene with aqueous hydrogen peroxide was investigated over various titanosilicate catalysts for the purpose of one-pot synthesis of ethylene glycol (EG). The effect of titanosilicate topology (Ti-MWW, TS-1, Ti-MCM-68 and Ti-MOR), solvent, Ti content, catalyst amount, H2O/H2O2 ratio, reaction temperature and time on the EG production have been studied in detail. The Ti-MWW/H2O2/H2O catalytic system showed the highest EG yield together with high H2O2 conversion and utilization efficiency for the oxidative hydration of ethylene. The mechanism for the titanosilicate-catalyzed hydration of ethylene oxide (EO) has also been considered, which then shed light on the active sites for the second step in the oxidative hydration of ethylene. The catalyst deactivation could be ascribed to that the target product of EG and other heavy by-products with high boiling points were deposited inside the channels. The used Ti-MWW can be reusable when subjected to the regeneration by high-temperature calcination. Amine-assisted structural rearrangement of Ti-MWW not only enhanced the catalytic activity but also improved its stability in the oxidative hydration of ethylene.