abstract
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)(3)Me] (1), [CpMo(CO)(3)(CH2-PC6H4-CO2Me] (2) and [CpMo(CO)(3)CH2COOH] (3) as catalyst precursors. An ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate, was used as both extractant and reaction medium, entrapping the active homogeneous Mo-VI catalysts that are formed in situ under the operating catalytic conditions (aqueous H2O2 as oxidant, 50 degrees 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.
keywords
TEMPERATURE IONIC LIQUIDS; OXIDATIVE DESULFURIZATION; ROOM-TEMPERATURE; HYDROGEN-PEROXIDE; DEEP DESULFURIZATION; OLEFIN EPOXIDATION; MOLECULAR-OXYGEN; METAL CATALYSIS; MODEL DIESEL; SELECTIVE OXIDATION
subject category
Chemistry; Engineering
authors
Juliao, D; Gomes, AC; Pillinger, M; Valenca, R; Ribeiro, JC; Goncalves, IS; Balula, SS
our authors
acknowledgements
This work was partly funded through the projects REQUIMTE-LAQV, POCI-01-0145-FEDER-007265 (FCT, Fundacao para a Ciencia e a Tecnologia Ref. UID/QUI/50006/2013) and CICECO - Aveiro Institute of Materials, POCI-01-0145-FEDER-007679 (FCT Ref. UID/CTM/50011/2013), financed by national funds through the FCT/MEC and when appropriate co-financed by FEDER (Fundo Europeu de Desenvolvimento Regional) under the PT2020 Partnership Agreement. The FCT and the European Union are acknowledged for grants to D.J. (SFRH/BD/102783/2014) and A.C.G. (SFRH/BPD/108541/2015) co-funded by MCTES and the European Social Fund through the program POPH of QREN.