Effect of Anions on the Epoxidation of Styrenes with H2O2 in the Presence of Ammonium Heptamolybdate(VI)– Dioctyltin Oxide Catalysts

The epoxidation of styrene, α-methylstyrene, β-methylstyrene, p-chlorostyrene, and m-divinylbenzene with H2O2 in the presence of ammonium heptamolybdate(VI)–dioctyltin oxide catalysts in CHCl3–H2O was studied. The addition of neutral salts, such as NaNO3 or Na2SO4, to the catalyst system prevented the successive hydration of styrene oxide once formed. The presence of KCl or NaCl almost suppressed the oxidation, while no substantial effect was observed in NaClO4. The various effects of these anions were related to the results concerning the coordination of anions to Mo(VI)-ions.