Desulfurization Simulated Gasoil

Desulfurization imitate Gas anointDesulfurization Simulated Gaspetroleum by Polyoxometalate/H2O2/ dome Liquid SystemArouna Dolo, Yu-Hui Luo, Wen-Wen Ma, Xin-Xin Lu, Yan Xu, Kaiwen Ma, Nah Traor, Hong ZhangAbstractThe Keggin-type atom smashers (Q)3+nPW12-nVnO40 (n= 1-3) were synthesized by noggin exchange for rock oil beginning/catalytic oxidation desulfurization (ECODS) of DBT, BT and 4,6-DMDBT. The samples were characterized by Fourier commute Infrared (FT-IR) spectra analysis, thermogravimetric analysis (TGA) and Ultraviolet-visible (UV-vis) absorption spectra analysis. The experimental results indicated that (STA)6PW9V3 exhibits superior catalytic activity and durability with rough 99.14% desulfurization dictate from the five hundred ppm model oil within 1 h at 40 , and no simply decrease in its catalytic performance was observed afterwards five dollar bill full-strength ECODS recycles with active 98% recovery rate. Therefore, the Keggin-type material is a promise a nd efficient catalyst for the catalytic oxidation desulfurization of diesel fuel.Keywords Catalysts, Polyvanadotungstates, inception/oxidation desulfurization, Ionic liquid, Keggin-type polyoxometalates1. IntroductionThe combustion of hydro hundred generates gaseous conta minute of arcants, such as SOx and dark species, which lead to environmental hazards, including acid rain, air contamination and ozone consumption 1. Hydrodesulfurization (HDS), a standard refining technology, is very efficient in removal of thiols, sulfides and disulfides. However, it is slight effective when dealing with refractory sulfur compounds such as benzothiophene (BT), dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT) 2. This attracts noted efforts to explore an efficient approach for sulfur removal from oil, including extractive desulfurization (EDS), oxidative desulfurization (ODS), biodesulfurization (BDS) and spongelike desulfurization (ADS) or their combination. Among them, extractive/catalytic oxidative desulfurization (ECODS) has emerged as an intriguing approach receivable to its superior desulfurization activity, selectivity and stability 3.Various catalysts, such as commercially getable molybdic compound 4, phosphotungstic acid,5 peroxotungsten complex 6 and polymolybdates 7 have demonstrated good efficiency with ECODS. However, phase-transfer confinement across the interface and lack of adaptive reaction environment in the hydrophobic ILs are the main drawbacks in these systems. The Keggin-type containing-vanadium POMs PMo12-nVnO40(3+n)- and PW12-nVnO40(3+n) have demonstrated to be an effective and robust catalyst for various oxidation reactions, including ketones, aldehydes, alcohols and sulfur infra mild conditions 8, 9. However, few reports on the catalytic oxidative desulfurization by PW12-nVnO40(3+n) encapsulated with entire alkyl chains have been reported.In this work, we used Keggin-type containing-vanadium POMs H3+nPW12-nVnO40 (n= 1- 3) grafted with a serial publication of alkyl chains, including stearyltrimethylammonium bromide (STABr), hexadecyltrimethylammonium bromide (HDABr), and dodecyltrimethylammonium bromide (DDABr) as catalysts, BmimPF6 as extractant resolving power in the presence of H2O2 as oxidant for desulfurization. The results show that, among the synthesized catalysts (STA)6PW9V3 exhibited superior activity. response parameters, such as the influence of vanadium structure, oil/catalyst plug ratio and H2O2 dosage on the desulfurization were investigated. From our experiments, it suggests that the higher number of vanadium-substituted to the catalyst results the offend catalytic activity.2. Experimental 2.1. Materials facilitySynthesis of H4PW11VO40 (PW11V), H5PW10V2O40 (PW10V2) and K6PW9V3O40 (PW9V3)PW11V , PW10V2 and PW9V3 were synthesized as reported in the literature 11, 12. Surfactant-Encapsulated POMs (SEPs) were synthesized via bean exchange of method of PW12-nVn and surfactants (STAB r, HDABr and DDAB), respectively. PW12-nVn were dissolved in water, whereas surfactants were dissolved in alcohol. The two solutions were mixed, filtered, washed with water and ethanol to begin with drying for 24 h to obtain the final products. All catalysts used in this work were characterized according to the reported literatures.2.2. ECODS for oil modelSynthesis of dome liquid and model oil Ionic liquid BmimPF6 was synthesized as mentioned in the literature 10. The ECODS was conducted via initially mixing model oil with BmimPF6 inside two-necked bottomed flask immersed in water bath at various temperature 40, 50 and 60 C, respectively. The ECODS commenced after addition of H2O2 30 wt. % into the (STA)6PW9V3 down the stairs stirring for 3h. modal(a) samples were collected at dissimilar reaction times from 10 min to 160 min. The remained sulfur-containing compounds in model oil after the reaction were canvas by GC.2.3. CharacterizationFT-IR spectra were measured on a Mattson Alpha-Centauri spectrometer in the range of 4000-400 cm-1. Thermogravimetric analysis was performed on Perkin-Elmer Thermal Analyzer under nitrogen atmosphere at heating of 5 C/min till 600 C. UV absorption was measured with Cary five hundred UV-Vis-NIR spectrophotometer.3. Results and discussionThe ECODS was tested in comparison with other desulfurization systems, such as the extraction, the chemical oxidation and the catalytic oxidation (Table 1). Interestingly, the ECODS system was superior to others desulfurization systems. This is due to the persistence of catalyst with IL and oxidant in the same reaction somehow stimulates invention effect, which stabilizes the oxidant and subsequently enhances activity. In addition, the high oil-model solubility in bean liquid results in less binding energy of adsorbents on the system, and then contributing to a much higher sulfur removal.Three different surfactants were used to synthesize (Q)6PW9V3, (Q)6PW10V2 and (Q)6PW11V (Q = STABr, HDABr and DDABr) to investigate the influence of surfactant alkyl-chain distance on the catalytic performance. As shown in Fig. 1, the efficiency of DBT removal in ECODS are about 99.14%, 95% and 81% by employ (STA)6PW9V3, (HDA)6PW9V3 and (DDA)6PW9V3 as catalysts, correspondingly. In contrast, surfactant-encapsulated POMs (Q)5PW10V2 and (Q) are slightly less efficient than (STA)6PW9V3.Fig 2 shows the removal of DBT at 40, 50 and 60 C, respectively. The results show that removal of DBT via ECODS increases with temperature rising. aft(prenominal) 10 minutes for the ECODS reaction, the DBT removal efficiency was 38.47% at 40 C, part 80.36% at 60 C. Also, the DBT removal efficiency became stable for all trio temperatures after an hour. These results depict the superior catalytic activity at 60 C. However, the excessive higher temperature will lead to thermal decomposition of H2O2, hence low desulfurization efficiency 14. As a result, although the catalytic effect is hibernating(a ) at 40 C, which took around 1 h to remove about 99% of sulfur, it is economically preferred due to low energy exist and higher H2O2 stability. In addition, the durability of (STA)6PW9V3 was investigated on DBT removal for five legal separation cycles. The results show that, the catalyst keeps around 98 % of its activity after consecutive 5 cycles (Fig S8). Furthermore, the catalyst, (STA)6PW9V3, reserved all its characteristic peaks without significant shift after the durability test (Fig S9).The ECODS capability of DBT, BT, 4,6-DMDBT were evaluated using (STA)6PW9V3 as catalyst. The achieved desulfurization efficiency were about 99.14%, 91.09% and 71.06% for DBT, 4,6-DMDBT and BT at 40 C within 1 h, respectively, as shown in Fig 3. The data reflects the superior ECODS efficiency of DBT compared to 4,6-DMDBT and BT resulting from distinct electron engrossment of BT (5.739), DBT (5.758) and 4,6-DMDBT (5.760) 15. Thereby, high electron density eases up sulfur removal and criminal ity versa. However, 4,6-DMBT is the exception due to the persistence of two methyl groups in carbon chain, which cause steric hindrance 16.4. ConclusionIn summary, the Keggin-type organic-inorganic framework catalysts, (Q)6PW11V, (Q)6PW10V2, (Q)6PW9V3 Q=C18H37N(CH3)3 (STA), C16H42N(CH3)3 (HDA, C12H3N(CH3)3 (DDA), were synthesized by ionic exchange approach for oil extraction/catalytic oxidation desulfurization. Their desulfurization efficiencies were investigated by varing reactants concentration and reaction parameters. Intriguingly, (STA)6PW9V3 with longer carbon chain and higher V content exhibits superior catalytic activity compared to its counterparts. The ECODS presents better performance compared to others systems. Furthermore, (STA)6PW9V3 exhibits a drastic durability. From the experiment, it maintained catalytic activity with 98% recovery rate after five consecutive ECODS cycles.AcknowledgmentWe gratefully acknowledge fiscal support by the NSF of China (21271038, 21071027), the China High-Tech Development 863 computer program (2007AA03Z218) and analysis and testing foundation of Northeast Normal University.References1 R. Martinez-Palou, R. Luque, Applications of ionic liquids in the removal of contaminants from refinery feedstocks an industrial perspective, Energy Environ. Sci. 7 (2014) 2414-2447.2 W. Jiang, W. Zhu, Y. Chang, Y. Chao, S. Yin, H. Liu, F. Zhu, H. Li, Ionic liquid extraction and catalytic oxidative desulfurization of fuels using dialkylpiperidinium tetrachloroferrates catalysts, Chem. Eng. J. 250 (2014) 48-54.3 S. Ribeiro, A.D.S. Barbosa, A.C. Gomes, M. Pillinger, I.S. Gonalves, L. Cunha-Silva, S.S. Balula, Catalytic oxidative desulfurization systems based on Keggin phosphotungstate and metal-organic framework MIL-101, Fuel Process. Technol. 116 (2013) 350-357.4 W. Zhu, H. Li, X. Jiang, Y. Yan, J. Lu, L. He, J. Xia, Commercially available molybdic compound-catalyzed ultra-deep desulfurization of fuels in ionic liquids, greenish Chem. 10 (2008) 641-646.5 H. Li, L. He, J. Lu, W. Zhu, X. Jiang, Y. Wang, Y. Yan, Deep Oxidative Desulfurization of Fuels Catalyzed by Phosphotungstic Acid in Ionic Liquids at Room Temperature, Energy Fuels 23 (2009) 1354-1357.6 X. Jiang, H. Li, W. Zhu, L. He, H. Shu, J. Lu, Deep desulfurization of fuels catalyzed by surfactant-type decatungstates using H2O2 as oxidant, Fuel 88 (2009) 431-436.7 L. He, H. Li, W. Zhu, J. Guo, X. Jiang, J. Lu, Y. Yan, Deep Oxidative Desulfurization of Fuels Using Peroxophosphomolybdate Catalysts in Ionic Liquids, Ind. Eng. Chem. Res. 47 (2008) 6890-6895.8 W. Guo, Z. Luo, H. Lv, C.L. Hill, Aerobic Oxidation of Formaldehyde Catalyzed by Polyvanadotungstates, ACS Catal. 4 (2014) 1154-1161.9 Y. Liu, S. Liu, S. Liu, D. Liang, S. Li, Q. Tang, X. Wang, J. Miao, Z. Shi, Z. Zheng, Facile Synthesis of a Nanocrystalline MetalOrganic Framework Impregnated with a Phosphovanadomolybdate and Its Remarkable Catalytic Performance in Ultradeep Oxidative Desulfurization, ChemC atChem 5 (2013) 3086-3091.10 S. CardaBroch, A. Berthod, D.W. Armstrong, resolvent properties of the 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid, Anal. Bioanal. Chem. 375 (2003) 191-199.11 P.J. Domaille, G. Herva, A. Taza, Vanadium(V) Substituted Dodecatungstophosphates, Inorganic Syntheses, New York John Wiley Sons 1990, p 96-104.12 G.A. Tsigdinos, C.J. Hallada, Molybdovanadophosphoric acids and their salts. I. Investigation of methods of preparation and characterization, Inorg. Chem. 7 (1968) 437-441.13 M. Akimoto, H. Ikeda, A. Okabe, E. Echigoya, 12-Heteropolymolybdates as catalysts for vapor-phase oxidative dehydrogenation of isobutyric acid 3. Molybdotungstophosphoric and molybdovanadophosphoric acids, J. Catal. 89 (1984) 196-208.14 D. Fang, Q. Wang, Y. Liu, L. Xia, S. Zang, High-Efficient OxidationExtraction Desulfurization Process by Ionic Liquid 1-Butyl-3-methyl-imidazolium Trifluoroacetic Acid, Energy Fuels 28 (2014) 6677-6682.15 Z. Jiang, H. L, Y. Zhang, C. Li, Oxidative Desulfurization of Fuel Oils, Chin. J. Catal. 32 (2011) 707-715.16 M. Zhang, W. Zhu, S. Xun, H. Li, Q. Gu, Z. Zhao, Q. Wang, Deep oxidative desulfurization of dibenzothiophene with POM-based hybrid materials in ionic liquids, Chem. Eng. J. 220 (2013) 328-336.HighlightsA series of Keggin-type catalyst was successfully synthesizedThe influence factors for catalytic oxidation desulfurization were discussed in detailAs synthesized catalyst exhibited superior catalytic activity and durability.Figure captionsFig. 1 Influence of surfactant alkyl-chain length on the catalytic oxidation of DBT. Reaction conditions 5 mL model oil (S content = 500 ppm) time = 1 h T = 40 C H2O2 = 64 L, BmimPF6 = 1 mL.Fig. 2 Influence of temperature on the removal of DBT. Reaction conditions 5 mL model oil (S content = 500 ppm) (STA)6PW9V3 = 3.5 mg time=3 h H2O2 = 64 L, BmimPF6 = 1 mL.Fig. 3 Influence of different sulfur-containing compounds. Reaction conditions 5 mL model oil S content (BT, DB T and 4,6-DMDBT was 250, 500 and 250 ppm respectively) (STA)6PW9V3 = 3.5 mg time = 3 h T = 40 C H2O2 = 64 L BmimPF6 = 1mL.Fig. 1Fig. 2Fig. 3TablesTable 1 Influence of different desulfurization systems on removal of DBTReaction conditions 5 mL model oil (S content=500 ppm) t=1 h T =40 C H2O2= 64 L, catalyst = 3.5 mg, BmimPF6=1 mL1