Homogeneous oxidation using an oil-soluble oxidant

tert

-amyl hydroperoxide(TAHP)

for ultra-deep desulfurization was performed under mild conditions in the presence of molybdenum oxide catalysts.Dibenzothio-phene(DBT)

benzothiophene(BT) and 4

6-dimethyl-dibenzothiophene(DMDBT)

which are the refractory sulfur compounds for hydrodesulfurization(HDS)

were employed as model substrates for a simulated diesel fuel.Activity of molybdenum oxide supported on a macroporous weak acidic resin was investigated.The mass conversion of DBT reached near 100% at 90℃ and a TAHP/DBT molar ratio of 3 with 1% of molybdenum oxide supported on Amberlite IRC-748 resin for 1 h.It was further found that the activities of the model substrates decreased in the order of DMDBTDBTBT.In the flow oxidation using TAHP as the oxidant

mass conversion of DBT increased remarkably from 61.3% to 98.5% when dropping the weight hourly space velocity(WHSV) from 40 h

-1

to 10 h

-1

.A series of experiments dealt with selectivity of this oxidation using TAHP revealed that the model unsaturated compounds

i.e.4

6

8-trimethyl-2-nonylene

and 2-methylnaphthalene did not affect the oxidation of DBT.Car-bazole had nearly no effect on the conversion of DBT using TAHP

but had some influence on the one using

tert

-butyl hydroperoxide(TBHP).The mass conversion of DBT decreased remarkably from 75.2% to 3.6% when the content of carbazole increased from 0 to 500 μg·g

-1

.In the flow oxidation using TAHP as the oxidant

the concentration o

f DBT in model fuels was reduced from 500 μg·g

-1

to 7.2 μg·g

-1

at WHSV of 10 h

-1

and then reduced to 3.8 μg·g

-1

by adsorption of Al

2

O

3

.