(583ch) Pd Catalyzed Oxidation of Glycerol: Effect of Different Supports

Glycerol oxidation has attracted the scientists around the world and has been of interest for the past two decades. Glycerol is a major side product in the synthesis of biodiesel (~yield 14%). A surplus of this product is expected to hit the market due to biodiesel’s renewable nature and less pollution. The motive behind the oxidation is to absorb part of this surplus and thereby improve the economics of biodiesel production by converting glycerol into the value added products. Glycerol oxidation is known for its complex reaction network with multiple side reactions that hamper the selectivity towards the desired product(s). The selectivity can be improved both, on micro (i.e. catalyst) level as well as on macro (i.e. reactor) level engineering. Palladium catalyzed Liquid-phase oxidation of glycerol in basic conditions (pH>>7) with different catalytic supports Al₂O₃, SiO_2, TiO₂ and activated carbon is studied. The reaction needs an intelligent choice of support to obtained desired activity and product distribution. The oxidation reactions were carried out in a batch reactor (Autoclave) for different catalyst supports under otherwise similar conditions. The product distribution varies with the support material. For carbon support, the apparent reaction rate was highest among all. It was found that the presence of transport limitations influences product selectivity significantly.  Catalysts are characterized using techniques such as TEM, BET, and TPD, and the results were used to explain the results obtained.