The conversion of glycerol to methyl lactate catalyzed by tin‐exchanged montmorillonite‐supported gold catalysts

Abstract

AbstractBACKGROUNDGlycerol is a versatile platform compound to produce valuable chemicals. One‐pot direct conversion of glycerol into methyl lactate with methanol as solvent is very attractive, because it can reduce intermediate steps and avoid the separation of glycerol/methanol mixtures.RESULTSA series of tin (Sn)‐exchanged montmorillonite(M)‐supported Au catalysts were prepared by a combination of ion exchange and colloidal deposition methods, and designed as bifunctional catalysts containing gold (Au) and solid acid. These catalysts were employed for one‐pot conversion of glycerol to methyl lactate in methanol. The Au/Sn(20)‐Mt catalyst gave a high yield of methyl lactate of 54% upon conversion of 0.25 mol L–1 glycerol methanol solution over 0.07 g catalyst at 210 °C under 3 MPa air for 5 h. The good performance of Au/Sn(20)‐Mt was ascribed to the coexistence of small Au particle and abundance of acid sites. The glycerol conversion remained almost unchanged in the five recycled runs, whereas the methyl lactate yield decreased after the first run but kept stably in the later four catalytic runs.CONCLUSIONSAmong the series of Sn‐exchanged Mt‐supported Au catalysts, Au/Sn(20)‐Mt showed the highest glycerol conversion and methyl lactate yield. Containing both small Au particles and having an abundance of acid sites contributed to the excellent catalytic activity of Au/Sn(20)‐Mt. © 2019 Society of Chemical Industry