Silver Cyanide Powder-Catalyzed Selective Epoxidation of Cyclohexene and Styrene with its Surface Activation by H₂O_2(aq) and Assisted by CH₃CN as a Non-Innocent Solvent

We undertake silver cyanide (AgCN) powder for its catalytic epoxidation of cyclohexene or styrene in CH₃CN with variable substrate-to-solvent volume ratios using H₂O_2(aq) at 60 °C. The reaction mixtures can facilely separate into organic and aqueous layers. Cyclohexene oxide can be produced in the organic layer with 100 % selectivity from the substrate cyclohexene, while styrene oxide was identified with 80 % selectivity against benzaldehyde in styrene oxidation. After reactions, we can recycle the AgCN particles with comparable bulk property clarified via XRD, XPS, XAS, FT-IR, and ¹³C-SS NMR spectroscopy. Using H₂¹⁸O₂ as the oxidant, both epoxide products and acetamide are highly enriched with ¹⁸O-atom, indicating that the π bond-activation is essential for forming the cyclohexene/styrene oxides in the organic and acetamide in the aqueous layers. The oxidation of cyclohexene/styrene catalyzed by AgCN powder through surface activation by H₂O_2(aq) and assisted by the non-innocent CH₃CN-originated acetamide can achieve highly selective π-bond activation with high reactivity.