Synthesis and characterization of sulfonated graphene as a highly active solid acid catalyst for the ester-exchange reaction

A new synthesis methodology of sulfonated graphene was developed. In this process, the number of hydroxyl groups in graphene was initially increased with n-BuLi. Then, in the presence of chlorosulfonic acid, sulfonic acid groups could be covalently immobilized to hydroxyl groups under mild conditions. Sulfonated graphene as a solid catalyst was applied for the reactions between various alcohols and ethyl acetate. The experimental results indicate that sulfonated graphene can catalyze the ester-exchange reaction efficiently.