Catalytic conversion of glycerol to value-added chemicals in alcohol

Abstract

With the aim to directly use the mixture of glycerol and methanol from the biodiesel production for value-added chemical production, catalytic conversion of refined glycerol to lactic acid (LA) and propylene glycol (PG) using mixed solid catalysts of CaO and CuO in methanol medium was first investigated. At the optimum condition, the yields of LA and PG achieved were 46mol% and 35mol%, respectively. For recycling the catalysts, a combined process of glycerol conversion to alkyl lactate was further investigated. Using this integrated process, 45mol% methyl lactate yield and 28mol% PG yield were achieved in methanol medium, and 45mol% ethyl lactate and 18mol% PG yield were achieved in ethanol medium. The test for crude glycerol conversion showed that the impurities had slightly negative effects on glycerol conversion and product yield in methanol medium but no obvious effect in ethanol medium. Similar glycerol conversion and product yield were obtained when the mixture of glycerol, methanol, and CaO from biodiesel production were directly used as starting material. This result suggests that the mixture from biodiesel production can be directly used to produce valued-added chemicals such as methyl lactate and PG.