In this work

the selectivities of catalytic oxidative desulfurization of gasoline and diesel fuel were investigated.The type and concentration of thiophenic sulfur in gasoline and diesel fuel were determined separately by gas chromatography with a sulfur chemiluminescence detector (GC-SCD).With activated carbon (AC) and 30％（mass）aqueous solution of H2O2 as catalyst and oxidant respectively

the experimental studies of oxidative desulfurization of gasoline and diesel were carried out.The effect of electron densities of sulfur atom of different organic sulfur species on the oxidative selectivity was discussed.The results showed that gasoline fuel contained mainly thiophene (T) and its derivatives

such as T containing 1-methyl (C1-T)

2-methyl (C2-T)

3- methyl (C3-T) substituents and benzothiophene (BT); diesel fuel contained mainly BT

BT alkylated derivatives

dibenzothiophene (DBT) and DBT alkylated derivatives.The organic sulfur species whose electron densities of sulfur atom were larger than 5.716 could be oxidized.The higher the electron density

the higher the oxidation rate，and the higher the oxidation reactivity.The reactivity decreased in the order of DBT alkylated derivatives > DBT > BT alkylated derivatives> BT> C3-T.However

in gasoline，the T

C1-T and C2-T whose electron densities of sulfur atom were smaller than 5.716 were difficult to be removed by the catalytic oxidation method.The use of oxidative desulfurization could reduce the concentration of total sulfur in the diesel to less than 10 μg8226;g-1 from original 1200 μg8226;g-1

and make that in gasoline reduce to 155 μg8226;g-1 from 320 μg8226;g-1.