Low-Temperature Oxidative Dehydrogenation of Propane by an O_2/H_2 Mixture over Pt-Heteropoly Acid Catalysts

摘要

Conversion of low paraffins into olefins is a subject of great industrial interest. According to thermodynamics, increasing temperature favors dehydrogenation, however, high-temperature process is accompanied by cracking. Oxidative conditions shift the equilibrium toward olefins, but give rise to their secondary conversion. As a result, low selectivity to olefins is typical for conventional processes of paraffins dehydrogenation. In the systems here presented high selectivity to olefins resulted from low temperature of the process and selective action of an oxidant. The catalysts containing platinum and PMo_(12)O_(40)~(3-) heteropoly anions were applied to oxidation of propane with a mixture of 02 and H2 gases. Catalytic functions of the system were strongly affected by acidity of the catalysts: it was oxygenation of propane to mainly acetone on the neutral catalyst containing Cs-salts of the heteropoly anions, and oxidation combined with dehydrogenation on acidic catalyst. In the second case, propene can be obtained as a predominant product of propane conversion.