Abstract
Polyoxometalate-based ionic liquid hybrid materials with a pyridinium cation, containing Brönsted acid sites, were synthesized and used as catalysts for the oxidation of model and real diesel fuels. Keggin-type polyoxometalates with the formulae [PMo12O40]3−, [PVMo11O40]4−, [PV2Mo10O40]4−, [PW12O40]3− were used as anions. It was shown that increasing the acid site strength leads to an increase of dibenzothiophene conversion to the corresponding sulfone. The best results were obtained in the presence of a catalyst, containing a nicotinic acid derivative as cation and phosphomolybdate as anion. The main factors affecting the process consisting of catalyst dosage, temperature, reaction time, oxidant dosage were investigated in detail. Under optimal conditions full oxidation of dibenzothiophene and more than a 90% desulfurization degree of real diesel fuel (initial sulfur content of 2050 ppm) were obtained (the oxidation conditions: NK-1 catalyst, molar ratio H2O2:S 10:1, molar ratio S:Mo 8:1, 1 mL MeCN, 70 °C, 1 h). The synthesized catalysts could be used five times with a slight decrease in activity.
Highlights
In recent years, the produced hydrocarbon feedstock has contained an increasing number of organosulfur compounds, which adversely affect the refining processes and the quality of the resulting fuels [1]
The results obtained show similar values of experimentally detected and calculated values which proves the composition of the synthesized catalysts and the proposed molar ratios of corresponding cation and anion
2800–3000 cm−1 are the stretching vibrations of the saturated C–H bond in NK-4 (Figure 1d). These results indicate the formation of the catalyst containing ionic liquid (IL), cation, and heteropolyacid anion
Summary
The produced hydrocarbon feedstock has contained an increasing number of organosulfur compounds, which adversely affect the refining processes and the quality of the resulting fuels [1]. In another article [26], it was shown that more than 90% of DBT can be removed by adding to hydrogen peroxide [(C2 H4 OH)N(CH3 )3 ]FeCl4 (ChFeCl4 ) and an ionic liquid (1-butyl-3-methylimidazole tetrafluoroborate [BMIM]BF4 or 1-n-octyl-3-methylimidazole tetrafluoroborate [OMIM]BF4 ) as a catalyst This catalytic system containing the IL and the catalyst can be separated and used up to five times without loss of activity. The Brønsted acid sites are presented by carboxylic groups, bonded with a pyridinium cation and the transition metal containing anion is presented by the phosphoromolybdate anion The advantage of such an approach is the possibility to provide a single catalyst having the high catalytic activity of transition metals and acids as well as the functions of an interfacial carrier
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
