Immobilized oxo- vanadium Schiff base on graphene oxide as an efficient and recyclable catalyst for the epoxidation of fatty acids and esters

Oxo-vanadiumSchiff base was covalently immobilized onto chemically functionalized graphene oxide (GO) using 3-aminopropyltriethoxysilane as a coupler. The loading of vanadyl Schiff base onto GO nanosheets was confirmed by FTIR, XRD, TGA, and inductively coupled plasma-atomic emission spectroscopy (ICP-AES). The synthesized heterogeneous catalyst was found to be efficient and selective for the epoxidation of fatty acids and esters using t-butyl hydroperoxide (TBHP) as an oxidant. Interestingly, the immobilized catalyst showed a higher catalytic efficiency than the homogeneous vanadyl acetylacetonate. The recycling experiment results indicated that the catalyst was highly stable and maintained very high activity, and selectivity even after being used for six cycles.