Dibenzothiophene Sulfone Research Articles

Amine modified nano-sized hierarchical hollow system for highly effective and stable oxidative-adsorptive desulfurization

Oxidative-adsorptive desulfurization (OADS) has become a frontier scientific topic. The main factors affecting the oxidation and adsorption performance are the polarity and size of porous catalysts. Herein, highly active and stable phosphotungstic acid immobilized on amino grafted nano-sized hierarchical hollow silica spheres (HPW-NH2-HHSS) was successfully prepared and completely characterized. The hierarchical hollow structure of HHSS support can be maintained after being functionalized with amine groups, and the active species of phosphotungstic acid H3PW12O40 (HPW) were well dispersed on the amine-modified HHSS and retained its Keggin structure of the heteropolyanions. The prepared catalyst was applied to simultaneous oxidation and adsorption of dibenzothiophene (DBT) from model fuel. The effects of contact time, the loading content of HPW, the dosage of catalyst, the [O]/[S] mole ratio, initial DBT concentration, and temperature on the removal efficiency of the OADS system were investigated. 20% HPW-NH2-HHSS demonstrated a high catalytic performance and its desulfurization efficiency could be reached to 99.36% in 30 min at a lower O/S rate (2.5). Meanwhile, the equilibrium adsorption capacity of dibenzothiophene sulfone (DBTO2) of this catalyst is about 374 mg g−1. Beside this there was no significant decline in catalyst performance after seven catalytic cycles, assigned to the chemical force between the positive charges of NH2 and the negative charges of HPW. It is the first time that this work involving the nano-sized hierarchical hollow system has been used for high-efficiency desulfurization and the theory has been advanced that the polar groups of catalysts replace polar solvents to adsorb S-oxidation products.

Fabrication of titanosilicate pillared MFI zeolites with tailored catalytic activity

Titanosilicate pillared MFI zeolite nanosheets were successfully synthesized by infiltrating the mixed tetraethyl orthosilicate (TEOS)/tetrabutyl orthotitanate (TBOT) solvent into the gallery space between adjacent MFI zeolite layers. The obtained zeolite catalysts were characterized using powder X-ray diffraction, N2 adsorption/desorption isotherms, scanning electron microscopy, transmission electron microscopy, ultraviolet-visible spectroscopy, X-ray photoelectron spectroscopy, and Fourier-transform infrared spectroscopy techniques. The H2O2 oxidation of dibenzothiophene (DBT) was used to evaluate the catalytic performance of the obtained titanosilicate pillared MFI zeolites. The conversion of DBT and selectivity of dibenzothiophene sulfone (DBTS) were most affected by the textural properties of the zeolites. This was attributed to the DBT and DBTS molecules being larger than micropores of the MFI zeolites. The conversion of DBT and yield of DBTS could be systematically tailored by tuning the molar ratio of the TEOS/TBOT solvent. These results implied that a balance between the meso- and microporosity of zeolites and tetrahedrally coordinated Ti (IV) active sites of titanosilicate pillars can be achieved for the preparation of desired catalysts during the oxidation of bulk S compounds.

Dibenzothiophene Sulfone Derivatives as Plasma Membrane Dyes.

Dibenzothiophene 5,5-dioxide (DBTOO) derivatives have recently been shown to processes utility as fluorescent cell dyes. In an effort to extend the functionality of DBTOO-based dyes to include the visualization of cellular membranes, two lipophilic DBTOO were synthesized and their ability to incorporate into the plasma membrane of HeLa cells was examined by fluorescent microscopy. The photophysical properties of the two new DBTOO derivatives were determined and both have good fluorescent quantum yields and a visible blue emission. Due to agreeable wavelengths of excitation and emission, a standard 4',6-diamindino-2-phenylindole (DAPI) filter set worked well with these dyes. After co-staining, it was confirmed that both DBTOO dyes localized in the plasma membrane. The quality of the overlap was quantified using Pearson correlation coefficient, which indicated a strong overlap between the DBTOO dyes and the standard plasma membrane dye. The novel dyes also displayed relatively low toxicity to the HeLa cells with IC50 between 10 and 100µm. Thus, this work reports a new use of DBTOO derivatives as fluorescent microscopy stains.

Synthesis of N-benzylated cobalt phthalocyaninetetrasulfonamide and its application in oxidative desulfurization catalysis

The FeCl2/K2CO3 catalyst system was used successfully for the synthesis of oil soluble N-benzylated cobalt phthalocyaninetetrasulfonamide by the reaction of benzyl alcohol on water-soluble cobalt phthalocyaninetetrasulfonamide via heating at 135 °C for 20 h under N2. The new oil-soluble peripherally N-benzylated phthalocyanine was characterized by elemental analysis, FT-IR, UV–vis, TG and mass spectrometry. The catalytic activity of this new cobalt complex for oxidation of dibenzothiophene (DBT) was evaluated in n-dodecane (a middle distillate model compound) using H2O2 as an oxidant. The acetonitrile was taken as an extracting solvent for further extracting DBT sulfoxide and sulfone. The novel peripherally substituted cobalt(II) complex showed better oxidative desulfurization catalytic activity than cobalt phthalocyanine and cobalt phthalocyaninetetrasulfonamide. DBT oxidation kinetics were evaluated by lumped nth- and first-order kinetic models. The maximum removal of the DBT was found to be 85% at the optimized dose and experimental conditions.

Preparation of WO3/CNT catalysts in presence of ionic liquid [C16mim]Cl and catalytic efficiency in oxidative desulfurization

AbstractBACKGROUNDWith the strict regulation for environmental protection, the removal of sulfur compounds from fuels is becoming more and more urgent. Hydrodesulfurization is one of the most widely used technologies in chemical industry, but its application is limited because of the harsh reaction conditions and the low efficiency in removal of aromatic organic sulfide. In this work, catalysts consisting of tungsten trioxide immobilized on carbon nanotubes (WO3/CNT) in the presence of ionic liquid [C16mim]Cl were prepared for the oxidative desulfurization of aromatic organic sulfide.RESULTSThe catalysts were systematically characterized by TG‐DSC, XRD, UV–visible, FTIR, Raman, SEM, TEM, XPS and BET. The dispersion of CNT and the crystal phase of WO3 on the carrier (CNT) were changed in the presence of ionic liquid [C16mim]Cl. The WO3 exists in tetrahedral form when the mass ratio of [C16mim]Cl to CNT is 2. The WO3/CNT catalyst demonstrates better activity in the oxidative desulfurization system, with the removal of dibenzothiophene (DBT) reaching 90.73% under optimal conditions. The oxidation process of DBT follows pseudo‐first‐order kinetics, and the activation energy is about 29.69 kJ mol−1. Dibenzothiophene sulfone (DBTO2) was determined to be the oxidative product of DBT.CONCLUSIONThe results illustrated that the oxidative desulfurization efficiency of different forms of WO3 loaded on the same carrier (CNT) followed the order tetrahedral WO3 > tetragonal phase WO3 > monoclinic phase WO3. © 2019 Society of Chemical Industry

Alkali Earth Catalysts Based on Mesoporous MCM-41 and Al-SBA-15 for Sulfone Removal from Middle Distillates.

Mg, Ca, and Ba catalysts supported on structured mesoporous silica oxides types MCM-41 and Al-SBA-15 were synthesized and investigated in sulfone cracking for sulfur removal from oxidized diesel fuel. Functional materials and catalysts were characterized by low-temperature nitrogen adsorption/desorption, transmission electron microscopy, and inductively coupled plasma atomic emission spectroscopy techniques. Catalytic tests were carried out in fixed-bed and batch reactors with a model compound dibenzothiophene sulfone and oxidized diesel fraction as a feed. MgO/MCM-41 and MgO/Al-MCM-41 possess high activity in sulfone cracking. The sulfur content in the diesel fraction decreases from initial 450 up to 100 ppmw. Catalysts can be regenerated for reuse in several cycles and may be potentially scaled up for industrial applications

Formation of Polycyclic Aromatic Hydrocarbon Oxidation Products in α-Pinene Secondary Organic Aerosol Particles Formed through Ozonolysis.

Accurate long-range atmospheric transport (LRAT) modeling of polycyclic aromatic hydrocarbons (PAHs) and PAH oxidation products (PAH-OPs) in secondary organic aerosol (SOA) particles relies on the known chemical composition of the particles. Four PAHs, phenanthrene (PHE), dibenzothiophene (DBT), pyrene (PYR), and benz(a)anthracene (BaA), were studied individually to identify and quantify PAH-OPs produced and incorporated into SOA particles formed by ozonolysis of α-pinene in the presence of PAH vapor. SOA particles were characterized using real-time in situ instrumentation, and collected on quartz fiber filters for offline analysis of PAHs and PAH-OPs. PAH-OPs were measured in all PAH experiments at equal or greater concentrations than the individual PAHs they were produced from. The total mass of PAH and PAH-OPs, relative to the total SOA mass, varied for different experiments on individual parent PAHs: PHE and 6 quantified PHE-OPs (3.0%), DBT and dibenzothiophene sulfone (4.9%), PYR and 3 quantified PYR-OPs (3.1%), and BaA and benz(a)anthracene-7,12-dione (0.26%). Further exposure of PAH-SOA to ozone generally increased the concentration ratio of PAH-OPs to PAH, suggesting longer atmospheric lifetimes for PAH-OPs, relative to PAHs. These data indicate that PAH-OPs are formed during SOA particle formation and growth.

Analysis of thiophenes in seawater: Molecularly imprinted polymer thin-film extraction with desorption electrospray ionization mass spectrometry

A new method coupling molecularly imprinted polymer thin-films (MIP thin-films) with desorption electrospray ionization mass spectrometry (DESI-MS) has been developed for indirect analysis of thiophene compounds in water. MIP thin-films were prepared on non-porous glass slides using a simple drop-casting fabrication method. The resulting films were used for indirect quantitative analysis of thiophene compounds in water by sorbing thiophene oxidation products (sulfones) to MIP films, then interrogating the MIP surface by DESI-MS. Oxidation of thiophenes to sulfones in water was achieved by reaction with a mixture of H2O2/formic acid at 65 °C for 2 h. DESI source parameters were optimized, and the optimal spray solvent composition was found to be MeOH:H2O (95:5 v/v) containing 0.5 mM NaCl. Among all sulfones formed, the protonated ion and sodium adduct signals were observed only for dibenzothiophene sulfone. The method was applied to dibenzothiophene in seawater, yielding a limit of detection at 3 ng L−1 and relative standard deviations (RSDs) below 8.0%. DESI-MS response was linear (R2 = 0.9841) over the range studied 0.1–10 μg L−1. With limited sample handling and ease of sample processing, many samples can be processed simultaneously making the method suitable for high throughput of screening environmental waters for dibenzothiophene and has the potential for detection its sulfone-metabolite.

Oxidative desulfurization of dibenzothiophenes over metallic and bimetallic supported ZSM-11 catalysts: xLa/yMo-ZSM-11 as an efficient bimetallic catalyst

In the present work, ZSM-11 zeolite was synthesized using the seed-assisted method and the proposed template of N,N-diethylaniline was used as a structure directing agent. Synthesized zeolite was characterized by FT-IR, XRD, FE-SEM and BET analysis. Oxide of intermediate metals of molybdenum, vanadium, lanthanum, cobalt, copper, and cerium was stabilized in the zeolite. The zeolite base catalysts applied as heterogeneous catalyst in the oxidative desulfurization (ODS) process for the model fuel including n-heptane, dibenzothiophene (DBT) with hydrogen peroxide as oxidant and ethanol as extractive solvent. The highest conversion percent of dibenzothiophene belongs to molybdenum, vanadium, and lanthanum. Different molar percentage of molybdenum and lanthanum were stabilized in zeolite and the yield of conversion of their dibenzothiophene to each other was compared. Finally, through the GC–MS reported data, dibenzothiophene sulfone and sulfur removal mechanism were identified. The results showed that the conversions of dibenzothiophene to dibenzothiophene sulfone achieve 100% under optimal experimental conditions.

Prospective Approach to the Anaerobic Bioconversion of Benzo- and Dibenzothiophene Sulfones to Sulfide.

Sulfur recovery from organic molecules such as toxic sulfones is an actual problem, and its solution through the use of environmentally friendly and nature-like processes looks attractive for research and application. For the first time, the possible bioconversion of organic sulfones (benzo-and dibenzothiophene sulfones) to inorganic sulfide under anaerobic conditions with simultaneous biogas production from glucose within a methanogenesis process is demonstrated. Biogas with a methane content of 50.7%–82.1% was obtained without H2S impurities. Methanogenesis with 99.7%–100% efficiency and 97.8%–100% conversion of benzo- and dibenzothiophene sulfones (up to 0.45 mM) to inorganic sulfide were obtained in eight days by using a combination of various anaerobic biocatalysts immobilized in a poly(vinyl alcohol) cryogel. Pure cell cultures of sulfate-reducing bacteria and/or H2-producing bacteria were tested as additives to the methanogenic activated sludge. The immobilized activated sludge “enhanced” by bacterial additives appeared to retain its properties and be usable multiple times for the conversion of sulfones under batch conditions.

Initial characterization of DszA for the high throughput validation of rationally designed DszC mutants

Sulfur dioxide production through fossil fuel combustion is a negative contributor to atmospheric pollution and human health. Currently, the preferred method for the removal of sulfur containing compounds from fossil fuels is though hydrodesulfurization. This process however, continues to be costly and inefficient in targeting certain common aromatic organosulfur contaminants like dibenzothiophene (DBT). Fortunately, the biodesulfurization (BDS) pathways in R. erythropolis and other bacterial species have shown promise in the removal of sulfur from such organosulfur compounds. However, improvements are still necessary for this pathway to become competitive and industrially applicable. Our current laboratory objectives are to rationally design the BDS pathway in R. erythropolis to decrease substrate specificity, starting with the first enzyme in the pathway DszC. To facilitate high‐throughput validation of our rationally designed DszC mutants, we will generate a strain of E. coli that harbors the three downstream biodesulfurization genes (DszA, DszB, and DszD). Here, we present our preliminary overexpression and biochemical characterization of the other enzymes in the BDS pathway, focusing on DszA, a flavin‐dependent monooxygenase. DszA crystals have also been produced and are being optimized for co‐crystallization with dibenzothiophene sulfone (DBTO2) substrate to accurately identify the substrate active site.Support or Funding InformationResearch Initiative for Science Enhancement (RISE), National Institute of Health (NIH), California State University NorthridgeThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Light-Enhanced Adsorptive Desulfurization of Dibenzothiophene Using Supported TiO<sub>2</sub>-ZrO<sub>2</sub>

Combustion of diesel fuel containing sulfur compounds emits SOx into atmosphere causing acid rain and respiratory illness in human. Dibenzothiophene (DBT) is one of the most difficult sulfur compounds in diesel to be removed by hydrodesulfurization (HDS). To produce ultra-low sulfur diesel (<15 ppmw-S), severe operating condition is required. As a result, production cost is increase. In this work, we investigated an alternative method for sulfur removal called Light-enhanced Adsorptive Desulfurization or L-ADS using supported TiO2-ZrO2. The TiO2-ZrO2 was loaded on commercial γ-Al2O3, fumed silica (FS), silica gel (SG) and zeolite (Z30) by wet-impregnation method. Impact of these supports on DBT removal were focused. Characteristic of the supported TiO2-ZrO2 was analyzed by N2 adsorption-desorption, scanning electron microscopy equipped with energy dispersive spectroscopy (SEM-EDS), and UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS). The presence of TiO2-ZrO2 greatly enhanced DBT removal compared to TiO2 and ZrO2. SG promoted DBT removal by facilitating the adsorption of dibenzothiophene sulfone (DBTO2), a product of DBT photocatalytic oxidation. Using TiO2-ZrO2/SG, 86% of sulfur was removed from 50 ppmw-S DBT/C16 within 4 h.

Investigations in enhancement biodesulfurization of model compounds by ultrasound pre-oxidation

In this study, complicated model sulfur compounds in crude oil were biodesulfurized in a batch process by microbial consortium enriched from oil contaminated soil. Dibenzothiophene (DBT) was selected as model sulfur compounds. Ultrasonic radiation was used to pre-oxidize the model sulfur compounds before the biodesulfurization (BDS) process. The enhancement mechanism of ultrasound pre-oxidation (UPO) on the biodesulfurization of DBT was investigated. The effects of initial conditions on the biodesulfurization of DBT in UPO/BDS system such as solution initial pH, DBT initial concentration, sulfur source, biocatalyst initial concentration, and incubation temperature were discussed. The results show that the application of UPO before BDS procedure significantly improved the efficiency of the biodesulfurization and allowed sulfur removal in shorter time through oxidizing DBT to DBT sulfone, resulting in shortening the “4S” pathway for biodesulfurization from 4 steps to 2 steps, enhancement in reaction velocity and enzyme-substrate affinity as well as reduction in substrate inhibition. The concentration of 2-HBP increased fast with the use of ultrasound pre-oxidation, which was dependent on solution initial pH, DBT initial concentration, sulfur source, biocatalyst initial concentration, and incubation temperature.

Thermally activated delayed fluorescence in dibenzothiophene sulfone derivatives: Theory and experiment

The photophysical properties are calculated for the dibenzothiophene sulfone substituted with various electron donor moieties:3,7-bis[N,N-di(4-tert-butylphenyl)amino]dibenzothiophene-S,S-dioxide (1L), 2,8-bis[N,N-di(4-tert-butylphenyl)amino]dibenzothiophene-S,S-dioxide (1A), and 2,8-bis[N,N-di(4 methoxyphenyl)amino]dibenzothiophene-S,S-dioxide (2A). It is shown that the linear arrangement of the electron donor substituents relative to the dibenzothiophene sulfone acceptor turns compound (1L) an efficient prompt fluorescent emitter, while the angular arrangement of the substituents decreases the efficiency of prompt fluorescence, but increases the efficiency of thermally activated delayed fluorescence (TADF). Replacing the auxiliary tert-butyl groups in the donor moieties by methoxy groups leads to an increase in kISC and kRISC. OLEDs are made with the studied compounds.

Unified catalytic oxidation–adsorption desulfurization for aromatic sulfur compounds with cyclohexanone peroxide over Ti-HMS

Three kinds of Ti-HMS zeolites have been synthesized by using different templates, and their catalytic performance was investigated in deep oxidation-adsorption desulfurization process. Various analysis techniques have been applied to investigate physical and chemical properties of the catalysts. Using cyclohexanone peroxide as an oxidant, the catalytic performance results show that Ti-HMS-12 exhibits highest desulfurization performance (99.9%) without solvents. Dibenzothiophene (DBT) was almost completely oxidized to the more polar DBT sulfone, which could be subsequently adsorbed on the Ti-HMS-12, achieving a unified processes of oxidative-adsorption desulfurization process. Furthermore, the catalyst was recycled for five runs with slight decreases in the catalytic performance and can be easily regenerated by methanol washing.

Catalytic oxidative desulfurization of model and real diesel over a molybdenum anchored metal-organic framework

In this work, we report the catalytic performance of a MoO2Cl2 anchored metal-organic framework, [email protected], in the oxidative desulfurization (ODS) process on a continuous fixed-bed reactor. [email protected] was examined as a catalyst in the oxidation of model oils containing dibenzothiophene (DBT), benzothiophene (BT) or 4,6-dimethyldibenzothiophene (4,6-DMDBT). In a 50-h ODS reaction of DBT at 70 °C, with tert-butyl hydroperoxide (TBHP) as the oxidant, a constant high DBT conversion of nearly 80% was observed along with a high oxidant utility of over 85%, where DBT was converted rapidly into DBT sulfone. XRD and ICP analysis show that the structure of [email protected] was well preserved, with no significant leaching of Mo species. In addition, [email protected] can also oxidize a hydrogenated diesel oil, and 74% sulfur removal efficiency was achieved, with an extraction recovery of 92.5% after acetonitrile extraction. Spectroscopic characterization confirmed the formation of a molybdenum peroxide complex from MoO2Cl2 under TBHP treatment, a plausible catalytic process was proposed based on the experiment evidence as well as FT-IR and FT-FIR characterization results.

Improved conversion of Dibenzothiophene into sulfone by surface display of Dibenzothiophene monooxygenase (DszC) in recombinant Escherichia coli

Biodesulfurization is an eco-friendly process for removing sulfur from petroleum fractions. The process could not be commercialized because of the inability of microorganisms to desulfurize a wide range of heterocyclic poly aromatic sulfur compounds like dibenzothiophene (DBT), 4, 6-Dimethyl DBT present in fuel and low desulfurization activity. In the present study, to improve the rates of conversion of dibenzothiophene to dibenzothiophene sulfone, the responsible enzyme dibenzothiophene monooxygenase DszC, is displayed on the surface of Escherichia coli. This helped in overcoming the mass transfer limitation and resulted in approximately 3 times faster conversion with respect to control (which contained intracellular enzyme). This is the first report demonstrating display of a biodesulfurization enzyme on bacterial cell surface.

Catalytic oxidative desulfurization of fuels in acidic deep eutectic solvents with [(C6H13)3P(C14H29)]3PMo12O40 as a catalyst

Deep eutectic solvents (DESs) are a new class of green solvents analogous to ionic liquids due to their biodegradable capacity and low cost. However, the direct extractive desulfurization of diesel oil by DESs cannot meet the government’s standard. In this work, amphiphilic polyoxometalates were synthesized and characterized by FT-IR and mass spectrometry. The oxidative desulfurization results showed that benzothiophene (BT) could be completely removed by employing a [(C6H13)3P(C14H29)]3PMo12O40, DES (ChCl/2Ac) and H2O2 system. It was also found that the organic cation of catalysts played a positive role in oxidative desulfurization. The reaction conditions, such as reaction temperature and time, the amount of catalyst and DES and H2O2/S (O/S) molar ratio, were optimized. Different sulfides were tested to determine the desulfurization selectivity of the optimal reaction system, and it was found that 97.2% of dibenzothiophene (DBT) could be removed followed by 80.7% of 4-MDBT and 76.0% of 4,6-DMDBT. After reaction, the IR spectra showed that the catalyst [(C6H13)3P(C14H29)]3PMo12O40 was stable during the reaction process and the oxidative product was dibenzothiophene sulfone (DBTO2). Furthermore, the catalyst can be regenerated and recycled for four runs with little loss of activity.

Asymmetric Dibenzothiophene Sulfones as Fluorescent Nuclear Stains.

Asymmetric dibenzothiophene S, S-dioxides (DBTOOs) were synthesized and their photophysical properties examined. Through examination, the molecules fluoresced at wavelengths between 371 and 492 nm with quantum yields of fluorescence nearing 0.59. Three of the sulfonic acid sodium salt analogues were chosen to be introduced to HeLa cells, resulting in illumination of the nucleus by fluorescent microscopy. These compounds function as nuclear stains while also affording the ability to predict the localization of the corresponding sulfoxide precursor to ground-state atomic oxygen.

Synthesis of WO3/mesoporous ZrO2 catalyst as a high-efficiency catalyst for catalytic oxidation of dibenzothiophene in diesel

The catalyst of WO3 highly dispersed on mesoporous ZrO2 was prepared by hydrothermal treatment and calcination. Ionic liquid templates with different cations and various calcination temperatures were taken into account to investigate factors that affect the structure of the catalysts. Wide-angle XRD, Raman, low-angle XRD, N2 adsorption–desorption, SEM, EDS-mapping and TEM analyses were employed to characterize the composition, morphology and the dispersion of WO3. It was found that [C16H33N(CH3)3]4SiW12O40 and 700 °C were the optimal ionic liquid template and calcination temperature; the obtained catalyst, expressed as 700-C16-WO3/ZrO2, exhibited the best catalytic activity in oxidation desulfurization. Dibenzothiophene (DBT) in the model oil could be oxidized to DBT sulfone (DBTO2) completely, certified by GC-MS analysis, under optimum conditions. The oxidative desulfurization efficiencies of different substrates catalyze by 700-C16-WO3/ZrO2, and the cycle performance on the oxidation of DBT were studied.