An amphiphilic graphene oxide-immobilized polyoxometalate-based ionic liquid: A highly efficient triphase transfer catalyst for the selective oxidation of alcohols with aqueous H2O2

Abstract Graphene oxide (GO) was utilized as an amphiphilic support to immobilize functionalized ionic liquid containing phosphotungstatic imidazolium (Im-PW) by an anion-exchange method. The physicochemical properties of the synthesized Im-PW/GO material were characterized by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, atomic force microscopy, scanning electron microscopy, transmission electron microscope, thermogravimetric analysis and contact angle measurements. In selective oxidation of benzyl alcohol to benzaldehyde, Im-PW/GO was determined to be an efficient triphase transfer catalyst, affording a high conversion (>90%) of benzyl alcohol and excellent selectivity (>99%) to benzaldehyde. Owing to the unique amphiphilic nature of GO support, the Im-PW/GO catalyst facilitated the contact between hydrophilic H 2 O 2 and hydrophobic benzyl alcohol, therefore demonstrated superior catalytic activity to the similar catalyst supported on conventional SBA-15. Moreover, it was readily recovered and reused up to four times without any significant loss in terms of its activity.