Molybdenum-modified mesoporous SiO₂ as an efficient Lewis acid catalyst for the acetylation of alcohols

A suitable, expeditious and well-organized approach for the acetylation of alcohols with acetic anhydride in the presence of 5%MoO₃-SiO₂ as an optimum environmentally benign heterogeneous catalyst was developed. The high surface area obtained for 5%MoO₃-SiO₂, 101 m² g^-1 compared to other catalysts, 22, 23, and 44 m² g^-1 for 5%WO₃-ZrO₂, 5%WO₃-SiO₂, and 5%MoO₃-ZrO₂, respectively, appears to be the driving force for better catalytic activity. Amongst the two dopants used, molybdenum oxide is the better dopant compared to its tungsten oxide counterpart. High yields of up to 86% were obtained with MoO₃ doping while WO₃ containing catalysts did not show any activity. Other reaction parameters such as reactor stirring speed, and solvent variation were studied and revealed that the optimum stirring speed is 400 rpm and cyclohexane is the best solvent. Thus, the utilization of affordable and nontoxic materials, short reaction times, reusability, and producibility of excellent yields of the desired products are the advantages of this procedure.