Preparation of Hβ zeolites with hierarchical pores and a study on the isomerization performance of α-pinene

The treatment of a beta zeolite with sodium hydroxide solution can partially desilicate the beta zeolite, thereby obtaining a mesoporous structure. The isomerization of alpha-pinene has been studied at 403 K and under atmospheric pressure. The catalytic materials were characterized by XRD, SEM, BET analysis, FT-IR spectroscopy and Py-IR spectroscopy. The results show that the pore structure of the beta zeolite can be effectively regulated by the sodium hydroxide solution. The microporous structure of the beta zeolite was destroyed. The crystallinity changed, the number of mesopores increased and the amount of acid slightly decreased. The catalyst after alkali treatment was applied to the isomerization reaction of alpha-pinene. The conversion of alpha-pinene increased to 96%, and the yield of camphene and limonene reached 67%. It was found that the isomerization reaction of alpha-pinene on the beta zeolite followed the first-order reaction kinetics, and the activation energy of the reaction was 41.58 kJ mol(-1).