Catalytic oxidation of acetic acid in supercritical water

The oxidation kinetics of acetic acid in supercritical water was examined in the presence of a solid catalyst consisting of supported copper, zinc, and cobalt oxides. For the conditions studied, the rate of catalysed oxidation was found to be well described by means of the power-law kinetic formulation based on the theory of non-uniform surfaces in which the rate is proportional to the 0.5 power of the oxygen mole fraction and 0.7 power of the acetic acid mole fraction. It is postulated that oxygen is adsorbed on active sites and that a reaction between adsorbed species and organic molecules from the van der Waals sublayer forms a carbonate complex that further decomposes to carbon dioxide and water. The apparent activation energy of catalysed oxidation is 110 kJ/mol.