Abstract:

Epoxidations of styrene and unsaturated fatty acid methyl esters(FAMEs) were studied using bicarbonateactivated hydrogen peroxide(BAP) system. The effects of bicarbonate， surfactants, adding modes of feedstocks, reaction time, the amount of H2O2 and reaction temperature on H2O2 decomposition and olefin epoxidation were investigated, respectively. When the molar ratio of n(styrene)∶n(H2O2)∶n(NaHCO3) is 1∶10∶0.25, the adding amount of cation surfactant cetyl trimethylammonium bromide（CTAB） is 1% mass fraction, the reaction temperature is less than 35 ℃, the reaction time is 6 h with slowly adding 30%H2O2 under stirring, the yield and selectivity of styrene oxide were up to 85% and 96%, respectively, and only a minor amount of benzaldehyde was formed. Cation surfactant CTAB, which carries active oxygen species HCO-4, can significantly promote the styrene conversion. However, the electrophilicity of active oxygen species HCO-4 is not enough to epoxide unsaturated FAMEs molecules with straight chains or containing an electron-defect C=C bond.

Key words: bicarbonate, H2O2 activation, olefin epoxidation, green process