Cesium salts of heteropoly acid immobilized mesoporous silica: An efficient catalyst for acylation of anisole

A series of Cs salt of phosphotungstic acid (Cs-PTA) supported on MCM-41 (Cs-PTA/MCM-41) was synthesized by a wet impregnation method and thoroughly characterized by using various analytical techniques, viz. X-ray diffraction, UV–Vis diffused reflectance spectroscopy (UV–Vis DRS), nitrogen adsorption desorption, scanning electron microscopy (SEM), Infrared spectra (FTIR), temperature programmed reduction (TPR), and temperature programmed desorption (TPD). The spectroscopic results revealed that Cs-PTA is highly dispersed on a MCM-41 surface. The 50 wt.% Cs-PTA supported on MCM-41 showed remarkable catalytic performance toward acylation of anisole reaction. The catalyst is regenerable by simple calcinations without appreciable loss in catalytic activity.

CsPTA/MCM-41 is an efficient catalyst for the acylation of anisole. The interaction of anhydride molecules with Brønsted acid sites of catalysts generates acylium, which attacks π-electrons of anisole to form methoxyacetophenones.Figure optionsDownload high-quality image (44 K)Download as PowerPoint slideResearch highlights
► Cs-PTA/MCM-41 is an efficient, stable and reusable solid acid catalyst.
► This catalyst is most effective towards acylation of anisole reaction.
► 50Cs-PTA/MCM-41 shows high activity and selectivity towards acylation of anisole.
► The catalytic activity decreased with increase in calcinations temperature.
► FTIR confirmed that Keggin structure remains unaltered when supported on MCM-41.