Oxidative desulfurization of fuel oil: Part I. Oxidation of dibenzothiophenes using tert-butyl hydroperoxide

Abstract

The oxidation of sulfur compounds in kerosene was conducted with tert-butyl hydroperoxide ( t-BuOOH) in the presence of various catalysts. The oxidation activities of dibenzothiophene (DBT) in kerosene for a series of Mo catalysts supported on Al 2O 3 with various Mo contents were estimated. The results show that the oxidation activity of DBT increased with increasing Mo content up to about 16 wt.% and decreased when Mo content was beyond this value. The oxidation of benzothiophene (BT), dibenzothiophene (DBT), 4-methyl dibenzothiophene (4-MDBT), and 4,6-dimethyl dibenzothiophene (4,6-DMDBT) dissolved in decalin was also carried out on 16 wt.% Mo/Al 2O 3 catalyst with t-BuOOH to investigate the oxidation reactivities of these sulfur compounds. The results indicated that the oxidation reactivities of these sulfur compounds decreased in the order of DBT>4-MDBT>4,6-DMDBT⪢BT. Analyses of the oxidative reactions of the sulfur compounds suggested that the oxidative reaction of each sulfur compound can be treated as a first-order reaction. The oxidation mechanism is then discussed.