Desulfurization of liquid fuels by extraction and sulfoxidation using H2O2 and [CpMo(CO)3R] as catalysts

• Published in: Applied catalysis. B, Environmental Environmental, 2018-08, Vol.230, p.177-183
• Main Authors: Julião, Diana, Gomes, Ana C., Pillinger, Martyn, Valença, Rita, Ribeiro, Jorge C., Gonçalves, Isabel S., Balula, Salete S.
• Format: Article
• Language: English
• Subjects: Cyclopentadienyl molybdenum complexes; Extraction; Hydrogen peroxide; Ionic liquid; Oxidative desulfurization
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2018.02.036

[Display omitted] •Catalytic precursor [CpMo(CO)3R] complexes for desulfurization of model and real fuels.•Efficient oxidation-extraction systems operating under sustainable conditions.•Optimization of RTIL and oxidant amounts to guarantee the sustainability and economical process.•Recyclable [CpMo(CO)3R]@RTIL systems for various consecutive cycles without loss of efficiency.•Sulfur removal efficiency of 83–84% was achieved for untreated diesel and jet fuel samples. Efficient and recyclable liquid–liquid extraction and catalytic oxidative desulfurization (ECODS) systems for the removal of refractory sulfur compounds from liquid fuels are reported that use the cyclopentadienyl molybdenum tricarbonyl complexes [CpMo(CO)3Me] (1), [CpMo(CO)3(CH2-pC6H4-CO2Me] (2) and [CpMo(CO)3CH2COOH] (3) as catalyst precursors. An ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate, was used as both extractant and reaction medium, entrapping the active homogeneous MoVI catalysts that are formed in situ under the operating catalytic conditions (aqueous H2O2 as oxidant, 50 °C). The high sulfoxidation activity of the catalyst formed from 1 was largely responsible for enabling >99% desulfurization within 1 h of a model oil containing 1-benzothiophene, dibenzothiophene, 4-methyldibenzothiophene and 4,6-dimethyldibenzothiophene (2000 ppm S). The IL/catalyst phase could be repeatedly recycled with no loss of desulfurization efficiency. By sequentially performing extractive desulfurization and ECODS steps, 83–84% sulfur removal was achieved for untreated real diesel and jet fuel samples with initial sulfur contents of ca. 2300 and 1100 ppm, respectively.