Modification of a heterogeneous catalyst: Sulfonated graphene oxide coated by SiO2 as an efficient catalyst for Beckmann rearrangement

Abstract

In this work and in continuation of our strategy for improving the performance of heterogeneous catalysts, the SiO2@GO-OSO3H catalyst was applied as a very efficient solid acid catalyst for the Beckmann rearrangement. This catalyst effectively catalyzed the liquid-phase Beckmann rearrangement of cyclohexanone oxime to caprolactam in high yield under very mild conditions. The improvement of GO-OSO3H catalyst in regard to its separation from reaction mixture is achieved by coating it with a mesoporous SiO2 layer. The influence of the operating parameters on the performance of the catalyst namely solvent, temperature, amount of catalyst, and time was studied.