Clicked graphene oxide as new support for the immobilization of peroxophosphotungstate: Efficient catalysts for the epoxidation of olefins

Peroxophosphotungstate (PW) anions were successfully immobilized on the surface of clicked graphene oxides and used as heterogeneous catalysts for the epoxidation of various olefins using H2O2 as oxidant. Graphene oxide (GO) was functionalized with azide groups through both grafting and tethering methods Then, supported ionic liquids were formed on the surface of GO through the Cu (I)-catalyzed azide-alkyne cycloaddition (CuAAC) click reaction. The clicked GO supported ionic liquids were used as appropriate supports for the immobilization of PW anions. Characterization of the prepared materials by various physicochemical methods showed that PW anions have been successfully immobilized on the surface of clicked GOs. Catalytic activities of these heterogeneous catalysts were evaluated in the epoxidation of olefins which showed that not only the catalysts are active, but also they could be reused several times without significant loss of their activities.