In situ IR study of dimethyl oxalate hydrogenation to ethylene glycol over Cu/SiO2 catalyst

The mechanism of dimethyl oxalate hydrogenation to ethylene glycol over Cu/SiO₂ catalyst was investigated by in situ Fourier transform infrared (FTIR) spectroscopy. It was found that dimethyl oxalate and methyl glycolate proceeded via dissociative adsorption on Cu/SiO₂ catalyst, and four main intermediates, CH₃OC(O)(O)C-M (1655 cm⁻¹), M-C(O)(O)C-M (1618 cm⁻¹), HOCH₂(O)C-M (1682 cm⁻¹) and CH₃O-M (2924-2926 cm⁻¹), were identified during the reaction. It was concluded that dimethyl oxalate hydrogenation to ethylene glycol mainly proceeded along the route: dimethyl oxalate → CH₃OC(O)(O)C-M → methyl glycolate → HOCH₂(O)C-M → ethylene glycol. Finally a schematic reaction network was proposed.