Polyoxometalate and copolymer-functionalized ionic liquid catalyst for esterification

A new room-temperature ionic liquid (RTIL) consisting of a polyoxometalate (POM) anion and tri-block copolymer (P123)-functionalized imidazolium cation was syn- thesized and utilized as a halogen-free catalyst for esterification. The catalytic system was a homogeneous solution at the beginning of the reaction, but an emulsion formed during the course of the reaction, and a progressive phase separation of the catalyst occurred at 0 °C over the course of 3 h. Dynamic light scattering (DLS), transmission electron microscopy (TEM), and Fourier transform/infrared spectroscopy (FT/IR) have been used to characterize the properties of the IL during the reaction. The new IL catalyst was found to be highly effi- cient in the esterification of various alcohols and can be recycled at least seven times.