Fast oxidative desulfurization of fuel oil using dialkylpyridinium tetrachloroferrates ionic liquids

• Published in: Fuel (Guildford) 2013-01, Vol.103, p.997-1002
• Main Authors: Nie, Yi, Dong, Yuxiao, Bai, Lu, Dong, Haifeng, Zhang, Xiangping
• Format: Article
• Language: English
• Subjects: Acidic ionic liquid; Applied sciences; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Fuel oil; Fuels; Oxidative desulfurization
• ISSN: 0016-2361; 1873-7153
• DOI: 10.1016/j.fuel.2012.07.071

A lower temperature is more suitable for the [C43MPy] FeCl4–H2O2–DBT oxidative desulfurization system. Kinetics of oxidative desulfurization of DBT by H2O2 and [C83MPy] FeCl4 is first-order with an apparent rate constant of 0.9951min−1 at 1/3 IL/oil mass ratio and 298K. [Display omitted] ► Iron-containing ILs were used as extractant and catalyst in ODS process. ► Iron-containing ILs showed S-removal of 100% and reached reaction equilibrium fast. ► Kinetics was first-order with an apparent rate constant of 0.9951min−1 at 298K. In this work, a series of Lewis acidic ionic liquids (ILs), dialkylpyridinium tetrachloroferrates [C43MPy] FeCl4,[C83MPy] FeCl4, and [C83MPy] FeCl4), was synthesized and utilized as extractant and catalyst to investigate the oxidative removal of dibenzothiophene (DBT) from model oil, with 30wt% hydrogen peroxide (H2O2) solution as oxidant. The effects of reaction time, temperature, H2O2/DBT molar ratio, initial sulfur content, IL/oil mass ratio, and alkyl chain length of IL cation ring on the DBT removal of model oil were investigated in detail. Dialkylpyridinium tetrachloroferrates ILs presented good catalytic activity and high extraction performance on the desulfurization of model oil, with the advantages of fast reaction equilibrium, high sulfur removal of 100%, low temperature, and low mass ratio of IL/oil. The desulfurization system could be recycled twice without a significant decrease in desulfurization activity. Kinetics of oxidative desulfurization of DBT by H2O2 and [C43MPy] FeCl4 is first-order with an apparent rate constant of 0.9951min−1 at 1/3 IL/oil mass ratio and 298K. [C83MPy] FeCl4 can reduce sulfur content in actual gasoline from 468ppm to 261ppm with a sulfur removal of 44% at IL/gasoline mass ratio of 1/3. The present work shows that fuel oil can be purified into ultralow sulfur fuels through further deep oxidative desulfurization using acidic ILs after hydrodesulfurization.