1016-05-3Relevant articles and documents
Non-hydrolytic synthesis of mesoporous silica-titania catalysts for the mild oxidation of sulfur compounds with hydrogen peroxide
Cojocariu, Ana Mihaela,Mutin, P. Hubert,Dumitriu, Emil,Fajula, Francois,Vioux, Andre,Hulea, Vasile
, p. 5357 - 5359 (2008)
A SiO2-TiO2 mesoporous xerogel prepared in one-step by a non-hydrolytic route shows excellent performance in the mild oxidation of sulfides, sulfoxides and thiophenes with aqueous solutions of H 2O2. The Royal Society of Chemistry.
Unique Thia-Baeyer–Villiger-Type Oxidation of Dibenzothiophene Sulfoxides Derivatives
Kong, Yang,Li, Jie,Markó, István E.,Shi, Wenjun,Zhou, Xinrui
, (2020)
The present research has demonstrated that selective C?S bond cleavages of dibenzothiophene and its derivatives are feasible by thia-Baeyer–Villiger type oxidation, i. e. the oxygen insertion process within a sulfoxide-carbon linkage, in the presence of porphyrin iron (III) and by ultraviolet irradiation originating from sunlight, high pressure Hg-lamp or residentially germicidal ultraviolet lamp under very mild conditions. This reaction with tert-butylhydroperoxide at 30.0 °C leads to dibenzo[1,2]oxathiin-6-oxide (PBS) in 83.2 % isolated yield or its hydrated products, 2-(2-hydroxyphenyl)-benzenesulfinic derivatives (HPBS) in near 100 % yield based HPLC data. PBS and HPBS are a type of biological products detected on the C?S bond cleavage step through various oxidative biodesulfurization (OBDS) pathways, and are useful synthetic intermediates and fine chemicals. These observations may contribute on understanding delicately molecular aspect of OBDS in the photosynthesis system, expanding the C-S cleavage chemistry of S-heterocyclic compounds and approaching toward biomemic desulfurization with respect to converting sulfur contaminants to chemically beneficial blocks as needed and performing under the ambient conditions.
Oxidation of dibenzothiophene by hydrogen peroxide catalyzed by solid bases
Figueras,Palomeque,Clacens
, p. 103 - 108 (2002)
The removal of sulfur compounds from hydrocarbon-based distillate fuels is essential due to environmental concerns (i.e., acid rain and airborne particulate material production), and because a few parts per million of sulfur are enough to poison the catalysts used for the purification of the exhaust gases of diesel cars. The oxidation of dibenzothiophene (DBT) by H2O2 at 333 K was investigated using the catalysts (hydrotalcite (HT) and MgLa mixed oxide) and solvents (methanol, acetonitrile, benzonitrile, acrylonitrile, and 3-methoxypropionitrile). High activity was found only after calcinations followed by rehydration of HT. Acetonitrile was the best solvent, while much lower reaction rates were observed in methanol. The decomposition of H2O2 into oxygen was observed for HT, and was the major reaction at > 353 K. This reaction did not occur in the absence of nitrile, and was faster over MgLa mixed oxide of higher basic strength. The activity increased with increasing Mg/Al ratio due to a lower rate of H2O2 decomposition attributed to a lower basicity of the solid.
Polyoxometalate as effective catalyst for the deep desulfurization of diesel oil
Wang, Rui,Zhang, Gaofei,Zhao, Haixia
, p. 117 - 121 (2010)
Aiming at the deep desulfurization of the diesel oil, a comparison of the catalytic effects of several Keggin type POMs, including H3PWxMo12-xO40 (x = 1, 3, 6), Cs2.5H0.5PW12O40, and H3PW12O40, was made, using the solution of DBT in normal octane as simulated diesel oil, H2O2 as oxidant, and acetonitrile as extractant. H3PW6Mo6O40 was found to be the best catalyst, with a desulfurization efficiency of 99.79% or higher. Hence, it is promising for the deep desulfurization of actual ODS process. The role of the main factors affecting the process including temperature, O/S molar ratio, initial sulfur concentration, and catalyst dosage, was investigated, whereby the favourable operating conditions were recommended as T = 60 °C, O/S = 15, and a catalyst dosage of 6.93 g (H3PW6Mo6O40)/L (simulated diesel). With the aid of GC-MS analysis, sulfone species was confirmed to be the only product after reaction for 150 min. Furthermore, macro-kinetics of the process catalyzed by H3PW6Mo6O40 was studied, from which the reaction orders were found to be 1.02 to DBT and 0.38 to H2O2, and the activation energy of the reaction was found to be 43.3 kJ/mol. Moreover, the catalyst recovered demonstrated almost the same activity as the fresh.
Synergy between bis(dimethyldioctylammonium) molybdate and tetraethylene glycol monooctyl ether: A winning combination for interfacial catalysis in thermo-controlled and switchable microemulsions
Hong, Bing,Leclercq, Lo?c,Collinet-Fressancourt, Marion,Lai, Jonathan,Bauduin, Pierre,Aubry, Jean-Marie,Nardello-Rataj, Véronique
, p. 142 - 149 (2015)
A simple thermo-responsive one-phase microemulsion (μem) is designed to enable the dark singlet oxidation of organic substrates while allowing a straightforward separation of the catalytic surfactant and products in two distinct phases by cooling down the reaction medium. This latter is prepared by combining a small amount (1%) of the catalytic surfactant bis(dimethyldioctylammonium) molybdate, [DiC8]2[MoO4], with the nonionic amphiphile tetraethylene glycol monooctyl ether, C8E4. Tensiometry and dynamic light scattering are used to rationalize the synergy between the two surfactants which strongly interact. The oxidation takes place in the effective one-phase Winsor IV system which separates into two phases (μem + oil, i.e. Winsor I) just by temperature change thanks to the presence of the thermosensitive C8E4. The thermal-controlled nanostructured reaction medium is applied to the ene reaction, [4+2] cycloaddition and sulfide oxidation.
Performance evaluation of the carbon nanotubes supported Cs2.5H0.5PW12O40 as efficient and recoverable catalyst for the oxidative removal of dibenzothiophene
Wang, Rui,Yu, Fengli,Zhang, Gaofei,Zhao, Haixia
, p. 37 - 41 (2010)
With the issues of increasingly stringent legislations on sulfur level in transportation fuels, clean fuels research including desulfurization has become a more important subject of environmental catalysis studies. Oxidative desulfurization (ODS) combined with extraction is one of the most promising desulfurization processes. With the loading of Cs2.5H0.5PW12O40, a new multi-walled carbon nanotube (MWNT) supported catalyst (Cs2.5H0.5PW12O40/MWNT) has been developed in this study. Through experimental evaluations, Cs2.5H0.5PW12O40/MWNT was found to be very effective for the oxidative removal of DBT, with a desulfurization efficiency of up to 100%. Factors affecting the process, including reaction temperature, O/S molar ratio, initial sulfur content, catalyst dosage, and pre-immersion time of the catalyst in H2O2 solution, were evaluated, and the favourable operating conditions were determined. Sulfone species was confirmed by GC-MS analysis to be the only product from DBT oxidation by H2O2 in the presence of Cs2.5H0.5PW12O40/MWNT after 160 min. Moreover, the new catalyst developed is recoverable. The recovered Cs2.5H0.5PW12O40/MWNT demonstrates quite close catalytic activity to that of the fresh. As a whole, Cs2.5H0.5PW12O40/MWNT has a high potential for using as an effective catalyst for deep desulfurization of diesel.
One-pot extractive and oxidative desulfurization of liquid fuels with molecular oxygen in ionic liquids
Wang, Jianlong,Guo, Qingping,Zhang, Changming,Li, Kaixi
, p. 59885 - 59889 (2014)
Benzothiophene (BT), dibenzothiophene (DBT) and 4,6-dimethlydibenzothiophene (4,6-DMDBT) were extracted from an oil phase to ionic liquid phase, and then oxidized to the corresponding sulfone by the cheap catalyst, N-hydroxyphthalimide (NHPI), using molecular oxygen as the oxidant in one-pot. The system can be recycled 5 times without a significant decrease in desulfurization.
Selective oxidation of sulfides to sulfoxides and sulfones by microwave thermolysis on wet silica-supported sodium periodates
Varma, Rajender S.,Saini, Rajesh K.,Meshram, Harshadas M.
, p. 6525 - 6528 (1997)
A variety of symmetrical and unsymmetrical sulfides have been selectively and expeditiously oxidized to either sulfoxides or sulfones in good yields using wet silica-supported sodium periodate under microwave thermolysis conditions.
Efficient molybdenum catalyzed chemoselective, solvent-free oxidation of sulfides to sulfones at room temperature
Hadigavabar, Ali Dadashi,Tabatabaeian, Khalil,Zanjanchi, Mohammad Ali,Mamaghani, Manouchehr
, p. 3829 - 3833 (2018)
An effcient and reusable molybdenum-based catalyst has been prepared by tethering dioxomolybdenumacetylacetonate complex, MoO2(acac)2, via postsynthesis modifcation of zeolite beta. The catalyst has been characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy-energy dispersive X-ray analysis (SEM-EDX) and inductively coupled plasma (ICP). The catalyst exhibited very high activity for the selective oxidation of sulfdes to sulfones at room temperature. The catalyst can be recycled and reused four times without signifcant loss of activity.
Tungstophosphoric Acid-catalyzed Oxidative Desulfurization of Light Oil with Hydrogen Peroxide in a Light Oil/Acetic Acid Biphasic System
Yazu, Kazumasa,Furuya, Takeshi,Miki, Keiji,Ukegawa, Koji
, p. 920 - 921 (2003)
Dibenzothiophenes were oxidized effectively with H2O 2 in the presence of 12-tungstophosphoric acid in the tetradecane/ AcOH biphasic system to give their corresponding sulfones as the major products. The oxidation proceeded in the AcOH phase and most of the sulfones distributed there, resulting in the successive removal of the sulfur compounds from the tetradecane phase. This biphasic oxidation system can effectively reduce the sulfur content in light oil.
