Modification of Acidic Properties of the Support for Pt–Sn/BEA Propane Dehydrogenation Catalysts

Resumo

Platinum–tin catalysts for propane dehydrogenation supported on a zeolite of the BEA framework type are studied. The presence of acid sites on the support leads to the occurrence of side reactions, which inhibit the achievement of a high propylene selectivity. To decrease the acidity of the support, the zeolite is subjected to dealumination with the preservation of the crystalline structure. The deposition of tin on this support leads to the incorporation of tin atoms into the zeolite framework, as confirmed by IR spectroscopy of adsorbed deuterated acetonitrile. The subsequent deposition of platinum leads to the occurrence of the Pt–Sn interaction, which provides a high selectivity for the target product and an increase in the agglomeration resistance of the active phase. In the presence of samples containing 0.5% of platinum and 0.5–1.0% of tin, at a reaction temperature of 550°C, a propane conversion of 26–28% at a propylene selectivity of up to 98.8% is achieved.