Polyaniline supported 12-tungstosilicic acid as the catalyst for acetals and ketals synthesis

A novel environmental friendly catalyst, H4SiW12O40/PAn was prepared and identified by FT-IR, XRD and TG/DTA. The optimal synthetic protocol was a PAn to H4SiW12O40 mass ratio of 1: 1, a 20 mL of methanol and a reaction time of 2 h at reflux. It was used in catalytic synthesis of ten important ketals and acetals with a high catalytic activity. With an aldehyde/ketone to glycol molar ratio of 1: 1.5 and a 1 wt% catalyst loading, the yields of ketals and acetals could reach 60.0%–93.8 % after 1 h.