Selective Oxidation of Glycerol to Dihydroxyacetone over Pt−Bi/C Catalyst: Optimization of Catalyst and Reaction Conditions

Glycerol selective oxidation to dihydroxyacetone was investigated systematically in a semibatch reactor over Pt−Bi/C catalyst. Catalysts with different metal loadings, supports, and preparation methods were synthesized, characterized, and tested. The sequential impregnation of Pt and then Bi, followed by NaBH 4 reduction, was the optimum synthesis method for high glycerol oxidation rate and maximum DHA yield. The optimum catalyst composition was determined to be 3 wt % Pt, 0.6 wt % Bi, supported on Norit Darco 20-40 mesh activated carbon (BET surface area 600 m 2 /g, average pore size 4 nm, average pore volume 0.53 cm 3 /g). In addition to the catalyst, the reaction conditions were also optimized by conducting experiments in the range of temperature 30−90 °C, oxygen pressure 0−180 psig, and initial pH 2−12. The optimum reaction conditions were identified as 80 °C, 30 psig, and initial pH = 2. Under these conditions, a maximum DHA yield of 48% was obtained at 80% glycerol conversion. The catalysts were characterized by using BET, ICP-OES, TEM, XRD, and XPS techniques.