Phosphosulfonic acid Supported on Nano Silica: A Novel and EfficientSolid Acid Catalyst for the Unsymmetrical Ethes Synthesis

The efficient synthesis of unsymmetrical ethers has been achieved in the presence of acatalytic amount of phosphosulfonic acid supported on nano silica as a novel environmentallybenign heterogeneous solid acid under solvent-free conditions.Phosphosulfonic acid, PSA, was easily prepared [۱] by simple mixing ofdiammonium hydrogen phosphate and chlorosulfonic acid in CH۲Cl۲ at room temperature(Scheme ۱). This reaction is easy and clean, because the by-products of the reaction are HCland NH۳ gases which are evolved from the reaction vessel immediately. The obtained solidacid was supported on silica gel by simple grinding.The efficiency of this solid acid was investigated in the preparation of unsymmetrical ethersthat one component of the reaction include (p-methoxybenzylalcohol or pmethylbenzylalcohol)and the others were short-chain alcohols. Similarly, In this case, theresults showed that products were produced with high yield and in short reaction time.