Heterogeneous catalysis for biodiesel synthesis and valorization of glycerol

In the present work, heterogeneous catalysts in the synthesis of biodiesel, glycerol-based chemicals i.e., mono-glyceride, glycerol carbonate and di-methyl carbonate are explored. Use of heterogeneous catalysts can make the production process cost-effective and environment-friendly. We evaluated three catalysts viz. ZnO/Zeolite, PbO/Zeolite, and MgO for the above mentioned syntheses. The conversion of jatropha oil and the yield of biodiesel on ZnO/zeolite were found to be around 100 and 93.8 %, respectively, at optimum reaction conditions. Selectivity for mono-glyceride in esterification of oleic acid with glycerol was found to be as high as 70–80 % in a conversion range of 60–90 %. Ammonia formed in the synthesis of glycerol carbonate and di-methyl carbonate can be used with CO₂ for the production of one of the reactants i.e., urea, thereby providing the opportunity to reduce carbon foot print.