New route for light olefins production from chloromethane over HSAPO-34 molecular sieve

HSAPO-34 molecular sieve was employed in chloromethane conversion and showed high performance in activity and selectivity in production of light olefins. Our detailed IR investigation allowed the identification of the active sites and the adsorbed species and demonstrated that the conversion started from 350 °C with alkoxy group as the intermediate. The fixed-bed catalytic testing evidenced that in the range of 350-500 °C, 70-80% of chloromethane was transferred to ethylene, propylene and butenes. Increasing reaction temperature favors the conversion and enhances the yield of lighter olefins. A very important reversible phenomenon, the breaking of AlOP bonds upon adsorption of HCl, a main product of reaction to generate a large amount of POH groups and the recovery of AlOP upon removal of HCl was revealed.