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

- Modification of a heterogeneous catalyst by coating it with SiO2.
- ε-caprolactam was produced through Beckmann rearrangement in mild conditions.
- The proposed method is a promising approach for saving time in large scale production.

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.