Immobilization of 12-Tungstophosphoric Acid on AlSBA-15 and Its Catalytic Activity for Acetylation

Abstract

Abstract 12-Tungstophosphoric heteropoly acid (TPA) with a Keggin structure was introduced into Al-incorporated mesoporous molecular sieves (AlSBA-15) by the incipient wetness method. The materials were characterized by X-ray diffraction, nitrogen adsorption, scanning electron microscopy, UV-Vis diffuse reflectance and Raman spectroscopy, which confirmed the Keggin and mesopore structure. Its catalytic activity was evaluated under solvent-free conditions in the liquid phase at 333–383 K for the propionylation of anisole with propionic anhydride. The catalysts used were AlSBA-15, 10%, 20%, and 40%TPA/AlSBA-15, and 20%TPA/MCM-48. In the propionylation of anisole with propionic anhydride, the substitution occurred predominantly at the para position. The 20%TPA/AlSBA-15 catalyst gave a total product yield of 48% with 98% selectivity towards 4-methoxypropiophenone. The regenerability of the catalyst was also studied and was found to be excellent.