Improvement of the catalytic activity of MCM-48 synthesized from metakaolinite in the alkylation of phenol with tert -butyl alcohol

M/MCM-48 (M and MCM-48 represent metakaolinite and Mobile composite of matter) mesoporous molecular sieves with good thermal and hydrothermal stabilities were synthesized by a hydrothermal method using metakaolinite as partial Si and Al sources. The samples were characterized by X-ray diffraction (XRD), NH3 temperature-programmed desorption (NH3-TPD), thermal gravimetric-differential scanning calorimeter (TG-DSC), transmission electron microscopy (TEM), Fourier transform-infrared (FT-IR) and N2 physical adsorption. The effect of crystallization time and temperature on the synthesis of M/MCM-48 was investigated. The catalytic activity of M/MCM-48 was evaluated by the alkylation of phenol with tert-butyl alcohol (TBA). M/MCM-48 with long-range ordering was synthesized at the crystallization temperature of 120°C for 36h. The H-M/MCM-48, H-Al/MCM-48 and H-MCM-48 catalysts (H represents the protonated sample) were prepared via an ion-exchanged method. Under comparable conditions, H-M/MCM-48 exhibited a higher catalytic activity than H-MCM-48. A maximum phenol conversion of 73.4% with a 4-tert-butylphenol selectivity of 70.0% was achieved over the H-M/MCM-48 catalyst at the reaction temperature of 140°C.