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.