Transesterification of dimethyl carbonate with phenol using Brønsted and Lewis acidic ionic liquids

Transesterification reaction of dimethyl carbonate with phenol to methylphenyl carbonate and diphenyl carbonate using dibutyltin oxide catalyst in conjunction with Brønsted and Lewis acidic ionic liquids was studied. It was observed that the use of ionic liquids significantly enhances the yield of diphenyl carbonate. The ionic liquid having p-toluenesulfonate as anion and metal halide (e.g. ZnCl2) as Lewis acid precursor exhibited higher activity and selectivity for diphenyl carbonate formation. Furthermore, the Brønsted and Lewis acidity of ionic liquids was measured by IR spectroscopy using pyridine as a probe and their Lewis acidity order was also determined.

Graphical AbstractTransesterification of dimethyl carbonate with phenol to yield methylphenyl carbonate and diphenyl carbonate using dibutyltin oxide catalyst in conjunction with Brønsted and Lewis acidic ionic liquids was studied. Brønsted and Lewis acidity of ionic liquids was measured using IR spectroscopy with the help of pyridine as a probe and also their Lewis acidity order was determined.Figure optionsDownload as PowerPoint slideResearch Highlights
► In present work, we developed a catalytic system of dibutyltin oxide and Brønsted/Lewis acidic ionic liquids which enhances the yield and selectivity of DPC.
► Brønsted and Lewis acidity of ionic liquids was measured by using pyridine as probe molecule.
► Relation between selectivity and Brønsted/Lewis acidity was discussed.
► Influence of various parameter such as catalyst loading ,mole ratio, was studied
► Effect of electron donating and withdrawing substituent on phenol was examined.