Multifunctional Heterogeneous Catalysts for the Selective Conversion of Glycerol into Methyl Lactate

[Image: see text] Multifunctional catalytic systems consisting of physical mixtures of Au nanoparticles (2–3 nm) supported on metal oxides and Sn-MCM-41 nanoparticles (50–120 nm) were synthesized and investigated for the selective conversion of glycerol to methyl lactate. The Au catalyst promotes the oxidation of glycerol to trioses, whereas the solid acid Sn-MCM-41 catalyzes the rearrangement of the intermediate trioses to methyl lactate. Among the supported Au nanoparticles, Au/CuO led to the highest yield and selectivity toward methyl lactate, while the Sn-MCM-41 nanoparticles showed much better catalytic performance than a benchmark solid acid catalyst (USY zeolite). The activity of the multifunctional catalytic system was further optimized by tuning the calcination temperature, the gold loading in the Au/CuO catalyst, and the Au/Sn molar ratio, reaching 63% yield of methyl lactate (ML) at 95% glycerol conversion. This catalytic system also showed excellent reusability. The catalytic results were rationalized on the basis of a detailed characterization by means of TEM, N(2)-physisorption, UV–vis spectroscopy, and by FT-IR using probe molecules (CO and ethanol).