Mo Schiff base-tungstate ionic hybrid with enhanced heterogeneous catalytic activity for epoxidation reactions

• A novel Mo Schiff base-tungstate hybrid is prepared.
• The hybrid catalyst leads to the heterogeneous epoxidation of alkenes with H2O2.
• The hybrid catalyst gives high conversion and selectivity.
• The catalyst can be easily recovered and reused.

A novel metal Schiff base-tungstate ionic hybrid (Mo–MimAM–WO4) was prepared by anion-exchange of Mo Schiff base functionalized imidazole ionic liquid with sodium tungstate. The resulting hybrid catalyst was fully characterized by 1H NMR, FT-IR, XRD, SEM, TGA, and XPS, and its catalytic activity was studied for the epoxidation of alkenes using aqueous H2O2 as the oxidant. The catalyst was found to be highly efficient and showed higher catalytic activity than its corresponding homogeneous and heterogeneous analogues Mo–MimAM and Na2WO4. After reaction, the catalyst can be easily recovered by filtration and reused for the next run. The synergistic effect between Mo Schiff base complex and tungstate is revealed to be responsible for the catalyst’s excellent performance in epoxidation.

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