Friedel–Crafts acylation of anisole with propionic anhydride over mesoporous superacid catalyst UDCaT-5

Abstract

The synthesis of 4-methoxypropiophenone, an intermediate for the production of fine chemicals and pharmaceuticals, was carried out via Friedel–Crafts acylation of anisole with propionic anhydride by using various solid acid catalysts. The reactions were carried out under solvent-free conditions. A novel mesoporous superacid catalyst UDCaT-5 developed in our laboratory was the most active, selective and robust. The conversion of propionic anhydride and selectivity for 4-methoxypropiophenone at an anisole to propionic anhydride mole ratio of 5:1, using UDCaT-5 (0.05 g/cm³) at 383 K were 57% and 98.6%, respectively. The effects of various reaction parameters on the rate of reaction and selectivity were investigated to deduce the intrinsic kinetics of the reaction. Based on the experimental data, a suitable kinetic model was developed and it follows the Eley–Rideal mechanism. The results are novel.