Enhanced Effect of the Mesoporous Carbon on Iron Carbide Catalyst for Hydrogenation of Dimethyl Oxalate to Ethanol

Abstract

Due to the low activity of bulk Fe 5 C 2 catalyst in the hydrogenation of dimethyl oxalate to ethanol, a supported Fe 5 C 2 catalyst was designed and prepared with mesoporous carbon as the carrier. For a comparison, two iron carbide catalysts supported on activated carbon and microporous carbon were also prepared. Based on the characterization results of IR, XRD, H 2 -TPR, CO-TPD, XPS and MES, the oxygen-containing functional groups (especially COOH group) on the surface of the carbon supports inhibit the formation of iron carbides, which are regarded as the active sites and play the key role in the hydrogenation of dimethyl oxalate to ethanol. However, the mesoporous carbon exhibits a more positive effect on the dispersion of iron particles than the other two carbon supports. As a result, the as-prepared mesoporous catalyst presents an excellent activity (the ethanol yield of 85.8 %) and stability in the hydrogenation of dimethyl oxalate. This work suggests a practical strategy in fabricating a supported iron carbides catalyst for the chemosynthesis of ethanol via DMO hydrogenation from syngas.

Epsilon-Iron Carbide for the Hydrogenation of Carbonyl Groups in Esters

“…The replacement of methanol solvent by 1,4-dioxane could offer a higher selectivity from ∼80% to >90%, , yet limited in practical operation for the cycle of produced methanol. Transition metal carbide catalysts, e.g., Hägg iron carbide (χ-Fe 5 C 2 ) and Mo 2 C, in contrast, afford a distinct reaction pathway with MA as an intermediate instead of EG. − χ-Fe 5 C 2 exhibited a higher EtOH selectivity of ∼90% due to the lack of C–C cleavage ability compared with Mo 2 C. Nevertheless, the activity of χ-Fe 5 C 2 is still far from satisfying with a sluggish kinetics of MA hydrogenation, as the stabilized formation and effect of iron carbides on the transformation of esters have been mysterious up to now.…”