SELECTIVE OXIDATION OF GLYCEROL ON A PLATINUM-BISMUTH CATALYST BY USING A FIXED-BED REACTOR

The selective oxidation of glycerol (GLY) using a fixed bed reactor packed with a Pt-Bi catalyst (weight ratio of Bi to Pt=0.2) supported on granular charcoal was performed. A new catalyst system to perform continuous oxidations was developed. Oxidation of a 50% aqueous solution of GLY at 50 degrees C, oxygen-to-GLY mole ratio of 2 and a GLY aq. soln. based LHSV (h(-1)) of 0.06 produced dihydroxyacetone (DBA) with a selectivity of ca. 80% at a GLY conversion of 80%. EPMA (electron probe micro analysis) line analysis of active BiPt catalysts showed the necessity of inner layer impregnation of both elements for selective oxidation of the secondary hydroxy group of GLY. Wood based granular charcoal with a high BET surface area (>1200 m(2)/g) and a low bulk density (<200 g/l) was the preferred catalyst support.