Use of ternary Cu/Zn/La mixed oxides for the hydrogenation/hydrogenolysis of hexyl hexanoate to 1-hexanol aimed at overcoming the issues of chromium-based systems

Cu-based catalysts are really attractive for the hydrogenation/hydrogenolysis of the esters to the corresponding alcohols, given their low cost and robustness, which make them already attractive for the methanol synthesis. In this work, hexyl hexanoate (HexHex) hydrogenolysis to 1-hexanol (HexOH) with different Cu-based catalysts was studied, e.g. binary Cu/Zn and ternary Cu/Zn/La catalyst mixed-oxides. For these evaluations, Cu/Zn/Cr mixed oxides were considered as benchmarks for the catalytic evaluations of our Cr-free catalysts. It was found that lanthanum effectively acted as a promoter, helping to improve the activity of the Cu active metal, and reducing the sinterization issue (35 mol% of conversion for the Cu/Zn versus 90 mol% for the Cu/Zn/La, working under the best reaction conditions). The catalytic performances of the Cu/Zn/La catalyst are comparable with those of the ternary Cu/Zn/Cr system (91 mol%), working under the same best reaction conditions, thus confirming the possibility of using our Cr-free catalytic systems for improving the sustainability of the HexOH synthesis.