Oxidation of Toluene on Supported and Unsupported LaCoO3 Perovskites Catalyst

Abstract

Perovskite type oxide are known to be catalysts for a number of reactions such as total and partial oxidation, hydrocracking, hydrogeneous, hydrogenolysis and reduction etc. Efforts has largely been directed towards synthesis of unsupported and supported perovskites oxides of moderates or high specific area, their bulk and surface properties and their role in heterogenous catalysis. Oxidation of aromatic and aliphatic hydrocarbon over LaMO3 (M=Al, Ni, Mn, Co, Fe, Cr etc.) perovskites have been studied. Vapour phase catalytic oxidation of toluene over perovskites Viz., LaCoO3, LaCoO3/ SiO2 and LaCoO3/Al2O3 has been studied. The characterization of the catalyst was carried out using technique Viz. I.R., Surface area, Packing density. Surface acidity, Surface basicity. The surface area measurements in the temperature range 350ºC to 600ºC. The maximum surface area & maximum activity was observed at 450ºC. The heterogeneous catalytic vapour phase oxidation of toluene give benzaldehyde, benzoic acid, maleic acid and CO2 as products over LaCoO3 and LaCoO3 supported on Al2O3 and SiO2 as catalyst. The LaCoO3 supported on Al2O3 has been found to be the most active and selective catalyst giving 84.0% selectivity for benzaldehyde at 450⁰C with surface area 78.9m2/g. The overall Kinetic analysis indicate that the oxidation of Toluene to benzaldehyde is first order. The order of catalytic reactivity is LaCoO3/Al2O3 > LaCoO3/ SiO2 > LaCoO3.