Selective hydrogenation of oxalic acid to glycolic acid and ethylene glycol with a ruthenium catalyst

Abstract

The hydrogenation of the oxalic acid was evaluated with a ruthenium micro-mesoporous catalyst (5 wt%/activated carbon, 710 m2 g−1, 0.39 cm3 g−1), at 120 °C–150 °C under 80.0 bar in a slurry reactor, for the development of glycolic acid and ethylene glycol productions. The kinetic behavior of the process based on a surface mechanism was established according to the Langmuir–Hinshelwood approach. The mass balance equations fitted to the experimental data provided orders of magnitude for the specific reaction rates, reaching 1.93 × 10–1 h−1 for the hydrogenation of oxalic acid into glycolic acid at 130 °C and 2.51 × 10–2 h−1 for the production of volatile products at 150 °C. The kinetic selectivities under these conditions, 130 °C and 150 °C, were circa 70% for the production of glycolic acid, while for the volatile compounds was reached 87%.