The epoxidation of electron-deficient a, β-unsaturated carbonyl compounds with different structures has been investigated in room temperature ionic liquid/water biphasic system by using hydrogen peroxide. The effects of reaction time, concentration of sodium hydroxide, amount of oxidant and substrates on the epoxidation were studied in detail, and moreover, the reaction mechanism for the epoxidation system was proposed. In comparison with conventional phase transfer catalysis, the ring-opening reaction of the epoxides can efficiently be inhibited in the novel system induced epoxidation of a, β-unsaturated carbonyl compounds besides its relatively simple and mild reaction conditions. Under optimal conditions, the conversion and selectivity of the epoxidation of a, β-unsaturated carbonyl compounds could reach to 100% and 98% , respectively

Key words: HYDROGEN PEROXIDE SOLUTION, PHOSPHORIC ACID P, GLYOXALINE P, REACTION MECHANISM, PENTENONE P, EPOXIDATION REACTION, SELECTIVITY, CATALYTIC REACTION