Oxidation of Glycerol to Dicarboxylic Acids Using Cobalt Catalysts

In this paper, the performance of cobalt-based catalysts was reported for oxidation of glycerol to dicarboxylic acids such as tartronic and oxalic acids. Cobalt catalysts supported on Mg3Al(OH)(y)(CO3)(z) structures prepared by a two-step modified sol gel method showed 100% glycerol conversion with 64% and 24% selectivity toward tartronic and oxalic acids under mild conditions (55-70 degrees C and 0.1 MPa O-2). Surface and bulk characterization by N-2 adsorption/desorption, X-ray diffraction, and temperature-programmed reduction reveals that the cobalt sites interacting with surface hydroxides are catalytically more active than those incorporated into a framework leading to selective glycerol oxidation to dicarboxylic acids in one pot. On the basis of the experiments at different cobalt contents, temperatures, and concentration time profiles, possible reaction pathways are discussed to explain the selectivity profile. Deactivation of the catalyst under certain conditions has been discussed as a result of loss of surface area due to structural changes.