Integrated glycerol- and ethanol-based chemical synthesis routes using Cu–Mg–Al LDH-derived catalysts without external hydrogen: Intervention of bio-ethanol co-fed with glycerol

Abstract

In order to secure the feed, a bio-based chemical production plant shall be designed to process more than one bio-based feedstock. However, the process usually requires costly H2 supply. Without H2 feeding, the effects of Cu on Cu0.3Mg1.7Al-LDO catalysts were investigated on the hydrogenolysis of glycerol with and without bio-ethanol co-feeding. As a result, the reduced catalyst dramatically increased the glycerol conversion and gave an apparently-high selectivity of chemicals such as 1,2-propandiol, ethyl lactate, and lactic acid. Apparently, besides as a hydrogen donor, ethanol also acted as a reactant that produced ethyl lactate via the esterification with lactic acid. In summary, Cu2+ and Cu+ sites promoted glycerol dehydration, the oxidation to lactic acid, and the esterification with ethanol to ethyl lactate whereas Cu0 was believed to promote the in-situ hydrogen formation from glycerol reforming. The integrated reaction pathways were also proposed and discussed.