Search

Exceptional selectivity of LaMnO3 perovskite supported Au catalysts for the oxidation of glycerol to the dicarboxylate tartronic acid is reported. Through using monometallic Au, Pt or bimetallic Au:Pt nanoparticles the tartronic acid yield could be altered significantly, with a maximum yield of 44% in 6 h with Au/LaMnO3 and 80% within 24 h. These LaMnO3 supported catalysts were compared with conventionally TiO2 supported catalysts, which at comparable reaction conditions produced lactic acid, via a dehydration pathway, in high yield and a maximum tartronic acid yield of only 9% was observed. The LaMnO3 catalysts produced minimal lactic acid regardless of the supported metal, showing that the support structure influences the prevalence of dehydration and oxidation pathways. The choice of metal nanoparticle influenced product selectivity along the oxidation pathway for both LaMnO3 and TiO2 supported catalysts. Au catalysts exhibited a higher selectivity to tartronic acid, whereas AuPt catalysts produced glyceric acid and Pt catalysts produced predominantly C–C scission products. [ABSTRACT FROM AUTHOR]

A series of MgO catalysts have been prepared by calcination of (MgCO3)4·Mg(OH)2 and these have been found to be effective for the transesterification of triglycerides with methanol at 200 °C. The calcination temperature controls the surface area, porosity and the surface structure and we observe that the optimal calcination temperature is in the range 550–700 °C as this provides a balance between high surface area, and hence high concentration of active sites, and the pore structure which permits access of the reactants. Using appropriate conditions conversions in excess of 98% could be obtained. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]