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

Abstract

The treatment of a β zeolite with sodium hydroxide solution can partially desilicate the β zeolite, thereby obtaining a mesoporous structure. The isomerization of α-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 β zeolite can be effectively regulated by the sodium hydroxide solution. The microporous structure of the β 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 α-pinene. The conversion of α-pinene increased to 96%, and the yield of camphene and limonene reached 67%. It was found that the isomerization reaction of α-pinene on the β zeolite followed the first-order reaction kinetics, and the activation energy of the reaction was 41.58 kJ mol⁻¹.