A search for alternative Deacon catalysts

High-throughput methods, emissivity-corrected infrared thermography (ecIRT) and a sequential 10-fold fixed bed gas phase reactor have been used to accelerate the development of new catalysts for the Deacon process (4 HCl + O-2 reversible arrow 2 Cl-2 + 2 H2O). Both setups were modified to withstand the corrosive process conditions. Besides the reactor equipment also the catalysts themselves often suffered corrosion during the reaction. To consider the catalyst corrosion the tested oxides were typically aged for 24 h under a HCl-O-2 atmosphere at reaction temperature. The experimentally observed stability of selected binary mixedmetal oxides is correlated with literature data for the bulk chlorination tendency of the pure oxides and the corresponding melting/sublimation point of the chloride. The starting binary mixed-metal oxides have been selected based on a set of thermodynamic data for bulk chlorination and chloride oxidation and doping of TiO2 and SnO2, which are preferentially used as catalyst supports in Deacon reactions. The best catalysts discovered were optimized through doping and composition variations. Characterization of the best materials is provided. (c) 2012 Elsevier B.V. All rights reserved.