Boosting Selective Oxidation of Ethylene to Ethylene Glycol Assisted by In situ Generated H2O2 from O2 Electroreduction

The in situ generated H₂O₂ from O₂ electroreduction over mesoporous carbon is applied to oxidize ethylene via titanium silicalite-1. The in situ generated ⋅OOH on the mesoporous carbon can form the key active species Ti-OOH over titanium silicalite-1 and oxidize ethylene. This route exhibits outstanding production rate and selectivity of ethylene glycol.

Abstract

Ethylene glycol is a useful organic compound and chemical intermediate for manufacturing various commodity chemicals of industrial importance. Nevertheless, the production of ethylene glycol in a green and safe manner is still a long-standing challenge. Here, we established an integrated, efficient pathway for oxidizing ethylene into ethylene glycol. Mesoporous carbon catalyst produces H₂O₂, and titanium silicalite-1 catalyst would subsequently oxidize ethylene into ethylene glycol with the in situ generated H₂O₂. This tandem route presents a remarkable activity, i.e., 86 % H₂O₂ conversion with 99 % ethylene glycol selectivity and 51.48 mmol g_ecat ⁻¹ h⁻¹ production rate at 0.4 V vs. reversible hydrogen electrode. Apart from generated H₂O₂ as an oxidant, there exists ⋅OOH intermediate which could omit the step of absorbing and dissociating H₂O₂ over titanium silicalite-1, showing faster reaction kinetics compared to the ex situ one. This work not only provides a new idea for yielding ethylene glycol but also demonstrates the superior of in situ generated H₂O₂ in tandem route.

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