THE PLATINUM-CATALYZED OXIDATION OF 2-PROPANOL

The platinum-catalyzed oxidation of 2-propanol was run over a series of single-turnover (STO) characterized Pt/CPG (Controlled Pore Glass) catalysts. Comparison of reaction rates with STO site densities showed that the oxidation was taking place on the more coordinatively unsaturated corner atoms on the catalysts. Specific site TOFs were found to be 5.5, 7.9, and 5.0 moles 02 uptake/mole of site/mm for the 3MI, 3MR, and 3MH sites, respectively. Initial rate data were obtained for reactions run at several 2-propanol concentrations at three separate oxygen pressures. These data were analyzed using the double reciprocal Lineweaver-Burke method commonly employed in enzyme kinetic determinations. The data obtained showed that oxygen was adsorbed about 200 times more strongly than 2-propanol in these reactions. A maximum rate value of 18 moles of O2 consumed/mole of active site/min was calculated. This value represents the maximum rate for the reaction when it is run under zero-order conditions for both reactants without diffusion limitations. The present data were obtained, however, under first order reaction conditions. Given the difference in reaction conditions, the experimentally determined TOF of 6 min-1 is not an unreasonable value. © 1993 Academic Press, Inc.