The oxidative desulfurization process of diesel became a research hot-point with advantages of mild operating condition, no hydrogen consumption as well as low operating expenses and capital charges, being superior to the hydrodesulfurization (HDS) process, and a viable alternative to replace for HDS. A new desulfurization method. catalytic oxidative desulfurization with NOx-air as a catalyst and with acetic acid as a promoter, for straight-run diesel was attempted and the better results were achieved, overcoming the shortcomings of normal oxidative desulfurization technology, i.e., expensive cost of oxidant H2O2 which cannot be regenerated and the discharge of waste water containing sulfur. The experimental results showed that the sulfur content of diesel feed dropped from 1039 to 299 mug/g after oxidation with NOx-air as a catalyst and with promoter acetic acid at 60degreesC for 70 min. Then the sweetened diesel was extracted by N, N-dimethylformamide (DMF) to remove the oxidized products. As a result, the sulfur amount in the extracted diesel was reduced to 152 mug/g, which sufficed the Europe U diesel specification of less than 300 mug/g, with desulfurization rate of 85.4% and oil volume yield of 93.7% after extraction at 60degreesC for four times when the volume ratio of extractant to diesel was 0.2.
