New catalysts based on the heteropoly acid-zeolite system for the synthesis of higher α-olefins by paraffin cracking

Abstract

Natural zeolites (clinoptilolite) from the Shankanay deposit in Almaty oblast were used to prepare catalysts for the synthesis of higher α-olefins by paraffin cracking. The modification of zeolite with inorganic and organic heteropoly acids resulted in an enhancement of catalytic activity. The olefin yield on the zeolite modified with heteropoly acids was as high as 36.6% after one run in a flow system at atmospheric pressure and temperatures of 500–525°C. The modification of natural zeolite with HPA led to an increase of 22 to 257 m2/g in the total surface area. The increase in catalytic activity after HPA deposition can be attributed to the formation of stable nanostructures with sizes of 1 to 4 nm, resulting in the emergence of stronger Bronsted acid sites. The catalyst works stably in the reaction-regeneration mode.