NaOH-Treated Hβ Zeolite: A Highly 4-Tert-butyl-phenol Selective Catalyst for Alkylation of Phenol with Tert-Butanol

The catalytic performance of H beta zeolite treated with different concentration of NaOH on the alkylation of tert-butanol with phenol was studied. The effect of NaOH concentration on the crystallinity, morphology, textural property and acidity of H beta zeolite was studied by X-ray diffraction (XRD), scanning electron microscope characterization (SEM), N2 adsorption-desorption, Fourier transform infrared spectroscopy (FT-IR) and pyridine adsorption infrared spectra (Py-IR) techniques. A certain concentration of NaOH treatment can regulate the pore structure of H beta zeolite and remove part of framework aluminum and framework silicon, thus achieving the purpose of regulating the pore structure and acidity of the catalyst. Though lower Bronsted to Lewis acid amount ratio when treated NaOH concentrations were 0.15 mol/L, leading to the increasing of selectivity to 4-TBP. The H beta-0.2 M showed the high selectivity of 90.21% for synthesis of 4-tert-butyl-phenol (4-TBP), compared with the unmodified parent zeolite, the selectivity of 4-TBP improved 16.7%.