An amphiphilic graphene oxide-based triphase catalyst for highly efficient synthesis of benzyl esters

Abstract

In this study, graphene oxide-grafted pyridine-based ionic liquids were prepared and used as novel and highly efficient triphase catalysts for the synthesis of benzyl esters by the nucleophilic substitution reaction of benzyl halide with carboxylic acid salt. The as-prepared catalysts were characterized through several technologies including Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, elemental analysis, atomic force microscopy and thermal gravimetric analysis. The catalysts showed excellent catalytic performances in the synthesis of benzyl esters by the above-mentioned reaction. High conversion of benzyl halide (99%) and selectivity of benzyl ester (97%) were obtained after 6h at 120°C over the catalysts. Furthermore, the as-prepared triphase catalysts could be easily recovered and reused at least five times without significant loss of catalytic activity. The amphiphilicity of graphene oxide played an important role in the transfer of carboxylic anions from the aqueous phase to the organic phase, which accelerated the nucleophilic substitution reaction of benzyl halide with carboxylic acid salt.