γ-Butyrolactone-Assisted Route for the Fast Synthesis of β-Zeolite and Its Application in the Alkylation of Benzene with Isobutylene

A fast synthetic methodology of β-zeolite with the assistance of γ-butyrolactone (GBL) has been developed in this paper, and the synthetic parameters are systematically investigated to obtain β-zeolite efficiently. Compared to the conventional synthetic system with a crystallization time of 120 h, GBL promotes the crystallization of β-zeolite in a much shorter time of 24 h. An accelerated nucleation mechanism of β-zeolite assisted by GBL is unraveled by X-ray diffraction, scanning electron microscopy, thermogravimetry–differential thermal analysis, Fourier transform infrared spectroscopy, and NMR techniques. The results demonstrate that GBL can adjust the pH value of the initial gels and enhance the combination of TEA+ with aluminosilicate species; in the meantime, the Hoffmann degradation of TEAOH is suppressed. In addition, the β-catalyst obtained with the assistance of GBL exhibits both a higher selectivity of tert-butylbenzene and excellent catalytic stability in the alkylation of benzene with isobutylene compared with the commercial β-catalyst with a similar SiO2/Al2O3 molar ratio.