Polyoxometalate-based ionic liquids as catalysts for deep desulfurization of fuels

• Published in: Fuel processing technology 2011-10, Vol.92 (10), p.1842-1848
• Main Authors: Zhu, Wenshuai, Huang, Wangli, Li, Huaming, Zhang, Ming, Jiang, Wei, Chen, Guangying, Han, Changri
• Format: Article
• Language: English
• Subjects: Applied sciences; Catalysis; catalysts; catalytic activity; Characterization; diesel fuel; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Fuels; hydrogen peroxide; ionic liquids; oxidants; oxidation; Oxidative desulfurization; Polyoxometalate-based ionic liquids; recycling; temperature
• ISSN: 0378-3820; 1873-7188
• DOI: 10.1016/j.fuproc.2011.04.030

In order to obtain the ultra low-sulfur diesel, deep desulfurization of diesel oil has become a vital subject of environmental catalysis studies. Extraction and catalytic oxidation desulfurization (ECODS) system is one of the most promising desulfurization processes. A series of Keggin-type POM-based ionic liquids hybrid materials [MIMPS] 3PW 12O 40·2H 2O (1-(3-sulfonic group) propyl-3-methyl imidazolium phosphotungstate), [Bmim] 3PW 12O 40 (1-butyl 3-methyl imidazolium phosphotungstate), [Bmim] 3PMo 12O 40 (1-butyl 3-methyl imidazolium phosphomolybdate) and [Bmim] 4SiW 12O 40 (1-butyl-3-methyl imidazolium silicotungstate) have been developed in this study, and the reaction has performed using the POM-ILs materials as catalysts, H 2O 2 as oxidant, and ionic liquid (IL) as solvent. Through experimental evaluations, [MIMPS] 3PW 12O 40·2H 2O was found to be the best catalyst, with an S-removal of 100% at 30 °C for 1 h. The main factors affecting the process including temperature, catalyst dosage, and O/S (H 2O 2/DBT) molar ratio were investigated in detail. Under the optimal conditions, DBT (dibenzothiophene) and 4,6-DMDBT (4,6-dimethyl-dibenzothiophene) could achieve high desulfurization efficiency. Moreover, the reaction system also exhibited high activity in actual diesel oil, which could be reduced from 1113 ppm to 198 ppm. The reaction system could recycle 8-times with a slight decrease in activity. [Display omitted] ► Several POM-based ILs were synthesized and characterized. ► New attempt with POM-based ILs as catalysts in removing DBT in fuels. ► High desulfurization was achieved in water-immiscible IL. ► Desulfurization differences among different POM-ILs catalysts have been explained.