A novel composite material(TD)composed of TS-1 microcrystalline and dendritic mesoporous silica nanospheres(DMSNs)was successfully prepared.The TD composite material had open pore structure and large specific surface ...A novel composite material(TD)composed of TS-1 microcrystalline and dendritic mesoporous silica nanospheres(DMSNs)was successfully prepared.The TD composite material had open pore structure and large specific surface area,which was conducive to the mass transfer of reactants and products.The Ti element in TS-1 could be used as an electron assistant,and the spillover d-electrons were conducive to the improvement of the sulfidation and dispersion of MoS_(2),thereby forming more type II MoS_(2) active phases.The incorporation of Ti could bring more Brønsted(B)and Lewis(L)acid,which was conducive to the hydrogenation pathway(HYD)selectivity(41.2%)of dibenzothiophene(DBT)hydrodesulfurization(HDS)and isomerization(ISO)route selectivity(21.9%)of 4,6-dimethyldibenzothiophene(4,6-DMDBT)HDS,thus improve the HDS activity of DBT and 4,6-DMDBT.NiMo/TD-70(Aging temperature=70℃)had the best HDS activities of DBT(99.0%)and 4,6-DMDBT(93.7%)due to its large open pore structure,good acidity,suitable metal-support interaction(MSI)and perfect dispersion of the metallic active sites.展开更多
Polychlorinated dibenzothiophenes(PCDTs)and their corresponding sulfone(PCDTO2)compounds are a group of important persistent organic pollutants.In the present study,geometrical optimization and subsequent calculations...Polychlorinated dibenzothiophenes(PCDTs)and their corresponding sulfone(PCDTO2)compounds are a group of important persistent organic pollutants.In the present study,geometrical optimization and subsequent calculations of electrostatic potentials(ESPs)on molecular surface have been performed for all 135 PCDTs and 135 PCDTO2 congeners at the HF/6-31G*level of theory.A number of statistically-based parameters have been extracted.Linear relationship between gas-chromatographic retention index(RI)and the structural descriptors have been established by multiple linear regression.The result shows that two descriptors derived from positive electrostatic potential on molecular surface,σ+^2 andπ,together with the molecular volume(Vmc)and the energy of the lowest unoccupied molecular orbital(ELUMO)can be well used to express the quantitative structure-retention relationship(QSRR)of PCDTs and PCDTO2.Predictive capability of the two models has been demonstrated by leave-one-out cross-validation with the cross-validated correlation coefficient(RCV)of 0.996 and 0.997,respectively.Furthermore,the predictive power of the models is further examined for the external test set.Correlation coefficients(R)between the observed and predicted RI values for the external test set are 0.997 and0.998,respectively,validating the robustness and good prediction of our model.The QSRR model established may provide again a powerful method for predicting chromatographic properties of aromatic organosulfur compounds.展开更多
By using the bimodal mesoporous silica(BMMS) as the carrier and butyl titanate as the titanium source, the TiO_2/BMMS catalyst was prepared. The samples were characterized by XRD, XRF, N_2 adsorption and desorption, F...By using the bimodal mesoporous silica(BMMS) as the carrier and butyl titanate as the titanium source, the TiO_2/BMMS catalyst was prepared. The samples were characterized by XRD, XRF, N_2 adsorption and desorption, FTIR, UVvis,SEM, EDS, and TEM techniques. The test results showed that TiO_2 was amorphous, the TiO_2/BMMS catalyst had an ordered bimodal mesoporous structure, and the chemical interaction existed between BMMS and TiO_2. Since the TiO_2/BMMS had a lower band gap, its photocatalytic activity was better than TiO_2. Under UV irradiation a one-pot PODS system was set up, using TiO_2/BMMS as the catalyst, H_2O_2 as the oxidant, and methanol as the solvent. The TiO_2/BMMS catalyst showed better photocatalytic activity than the mono-modal mesoporous TiO_2/SBA-15 catalyst, and the desulfurization rate of dibenzothiophene(DBT) over TiO_2/BMMS catalyst could reach 99._2%. The TiO_2/BMMS catalyst also had so good stability that the desulfurization rate of DBT did not drop apparently after 8 cycles of reusing, and could still be close to 90%.展开更多
Supported ionic liquid(IL) catalysts [C_nmim]_3PMo_(12)O_(40)/Am TiO_2(amorphous TiO_2) were synthesized through a one-step method for extraction coupled catalytic oxidative desulfurization(ECODS) system. Characteriza...Supported ionic liquid(IL) catalysts [C_nmim]_3PMo_(12)O_(40)/Am TiO_2(amorphous TiO_2) were synthesized through a one-step method for extraction coupled catalytic oxidative desulfurization(ECODS) system. Characterizations such as FTIR, DRS,wide-angle XRD, N_2 adsorption–desorption and XPS were applied to analyze the morphology and Keggin structure of the catalysts. In ECODS with hydrogen peroxide as the oxidant, it was found that ILs with longer alkyl chains in the cationic moiety had a better effect on the removal of dibenzothiophene. The desulfurization could reach 100% under optimal conditions, and GC–MS analysis was employed to detect the oxidized product after the reaction. Factors affecting the desulfurization efficiencies were discussed, and a possible mechanism was proposed. In addition, cyclic experiments were also conducted to investigate the recyclability of the supported catalyst. The catalytic activity of [C_(16)mim]_3 PMo_(12)O_(40)/Am TiO_2 only dropped from 100% to 92.9% after ten cycles, demonstrating the good recycling performance of the catalyst and its potential industrial application.展开更多
In this research, the degradation of dibenzothiophene(DBT) was investigated by using Pseudomonas sp. LKY-5 isolated from oil contaminated soil. The response surface methodology(RSM) based on the Box-Behnken design(BBD...In this research, the degradation of dibenzothiophene(DBT) was investigated by using Pseudomonas sp. LKY-5 isolated from oil contaminated soil. The response surface methodology(RSM) based on the Box-Behnken design(BBD) was applied for evaluating the interactive effects of four independent variables including substrate concentration, temperature, pH and agitation rate on the DBT removal response. A total of 29 experiments for four factors at three levels were conducted in present study. A second-order regression model was then developed, and the analysis of variance(ANOVA) illustrated that the proposed quadratic model could be utilized to navigate the design space. The value of determination coefficient(R2=0.953 4) indicated a satisfactory agreement between the quadratic model and the experimental data. It was found that DBT removal was more significantly affected(P<0.000 1) by substrate concentration compared with other three parameters. An 100% degradation of DBT could be obtained by Pseudomonas sp. LKY-5 at a substrate concentration of 100 mg/L.展开更多
The potential of carrying out oxidative desulfurization(ODS) using oxygen as an oxidant was explored in this work. n-Octane firstly reacted with oxygen to produce hydroperoxides in-situ, which were then used as oxidan...The potential of carrying out oxidative desulfurization(ODS) using oxygen as an oxidant was explored in this work. n-Octane firstly reacted with oxygen to produce hydroperoxides in-situ, which were then used as oxidants to oxidize the dibenzothiophene(DBT) in the absence of catalysts. The hydroperoxides generated in-situ were effective in oxidizing DBT to its corresponding dibenzothiophene sulfone(DBTO_2) which was characterized by FT-IR and ~1H-NMR. The removal rate of DBT could reached 98.4% under conditions covering a temperaure of 140℃, a rection duration of 4 h, and an oxygen partial pressure of 0.4 MPa. The influences of different hydrocarbon components in diesel on DBT removal were investigated. The results showed that cyclohexane and n-dodecane had no effect on the removal of DBT, but xylene had a slight negative effect on DBT removal. A possible oxidation mechanism was proposed and the concentration of hydroperoxides in both O_2-oxidized octane and model diesel were detected.展开更多
In this research,1-butyl-pyridinium tetrafluoroborate([C4Py][BF4]-)was prepared by ion exchange method and was characterized by1H-NM R,13C-NM R,and FT-IR techniques.The synthesized ionic liquid w as used for removal o...In this research,1-butyl-pyridinium tetrafluoroborate([C4Py][BF4]-)was prepared by ion exchange method and was characterized by1H-NM R,13C-NM R,and FT-IR techniques.The synthesized ionic liquid w as used for removal of dibenzothiophene as a typical organosulfur pollutant from organic medium.The effect of different parameters on the extraction efficiency w as studied and optimized.At the optimized conditions,97.68%of dibenzothiophene w as extracted from 1 000 mg/L n-hexane solution.The extraction efficiency obtained in this w ork w as higher than the previous reported values.The desulfurization reaction w as kinetically follow ed the second order mechanism.The ionic liquid w as reusable and after four regeneration cycles 97%of its original extraction efficiency w as retained.展开更多
The aim of the current work is to synthesize the new heterocyclic pentacyclic condensed systems that combine benzothiophen and benzimidazole/triazole into one molecule. The dibenzothiophene was taken as an initial com...The aim of the current work is to synthesize the new heterocyclic pentacyclic condensed systems that combine benzothiophen and benzimidazole/triazole into one molecule. The dibenzothiophene was taken as an initial compound and by consistent “extension” was annihilated the imidazole and triazole nucleuses. As a result two new pentacyclic systems were produced: 3H-, 7H-diimidazole[4,5-b][5,4-g] dibenzothiophene-5,5-dioxide and 3H-, 7H-ditriazole[4,5-b][5,4-g] dibenzothiophene-5,5-dioxide with the promising antimi-crobial activity. Their spectral characteristics were studied.展开更多
Density functional methods have been used for the calculation of electronic structures, electronic transitions, vertical electron affinities and intermolecular reorganization energies for tri-aryl substituted dibenzot...Density functional methods have been used for the calculation of electronic structures, electronic transitions, vertical electron affinities and intermolecular reorganization energies for tri-aryl substituted dibenzothiophenes. These model compounds were then compared to the predicted values for dibenzo[b,d]thiophen-2-yltriphenylsilane (DBTSI 2) and to dibenzo[b,d]thiophene-2,8-diylbis(diphenylphosphine oxide) (PO15), known electron transport molecules. The results indicate that these model compounds can be used in a blue OLED system.展开更多
In this work, the possibility of enhanced activity during the hydrodesulfurization of dibenzothiophene over certain nano-MoS<sub>2</sub> catalyst due to the presence of H<sub>2</sub>S was exami...In this work, the possibility of enhanced activity during the hydrodesulfurization of dibenzothiophene over certain nano-MoS<sub>2</sub> catalyst due to the presence of H<sub>2</sub>S was examined by focusing on the reaction kinetics. With H<sub>2</sub>S generated <i>in situ</i>, the overall reaction followed the autocatalytic rate law;while in the absence of H<sub>2</sub>S the kinetics indicated a pseudo-first-order reaction. H<sub>2</sub>S appears to modify the relative contributions of parallel hydrogenation and desulfurization reactions by drastically increasing the hydrogenation rate. Kinetic models were developed that describe the hydrodesulfurization reaction at various H<sub>2</sub>S concentrations, and the kinetic parameters and adsorption equilibrium constants associated with this process were estimated by fitting the experimental data. The results suggest that the promotion and/or inhibition of hydrodesulfurization by H<sub>2</sub>S likely result from the same overall reaction mechanism.展开更多
Sulfur emission through fuel combustion is a global problem because it is a major cause of acid rain. Crud oil contains many heterocyclic organic sulfur compounds, among which dibenzothiophene(DBT) and DBTs bearing al...Sulfur emission through fuel combustion is a global problem because it is a major cause of acid rain. Crud oil contains many heterocyclic organic sulfur compounds, among which dibenzothiophene(DBT) and DBTs bearing alkyl substitutions usually are representative compounds. A strain was isolated from refinery sludge and identified as Corynebacterium ZD-1. The behavior of DBT degradation by ZD-1 in aqueous phase was investigated. Corynebacterium ZD-1 could metabolize DBT to 2-hydroxybiphenyl(2-HBP) as the dead-end metabolite through a sulfur-specific pathway. In shake flask culture, ZD-1 had its maximal desulfurization activity in the late exponential growth phase and the specific production rate of 2-HBP was about 0.14(mmol·kg dry cell -1·min -1, mmol·KDC -1·min -1). Active resting cells for desulfurization should be prepared only in this period. 2-HBP inhibited the growth of strain ZD-1, the production of DBT degradation enzymes, and the activity of enzymes. Sulfate inhibited the production of dibenzothiophene(DBT) degradation enzymes but had no effect on the enzymes’ activity. The production rates of 2-HBP at lower cell densities were higher and the maximum amount conversion of DBT to 2-HBP(0.067 mmol/L) after 8 h was gained at 9.2 g dry cell/L rather higher cell density. The results indicated that this newly isolated strain could be a promising biocatalyst for DBT desulfurization.展开更多
Aromatic fractions of 140 oils and condensates that originated from different types of source rocks(marine shale, terrestrial shale and marine carbonate) were analyzed using gas chromatography–mass spectrometry(GC–M...Aromatic fractions of 140 oils and condensates that originated from different types of source rocks(marine shale, terrestrial shale and marine carbonate) were analyzed using gas chromatography–mass spectrometry(GC–MS) to investigate the relative distributions of methylated dibenzothiophenes with respect to thermal maturity. The positions of methyl groups of trimethyldibenzothiophene isomers(TMDBTs) including those used in the definition of maturity indicator TMDBT index in previous studies were firmly identified by co-elution of internal standards in GC–MS analysis and by comparing with reported retention indices. A new maturity ratio related to dimethyldibenzothiophenes(DMDBTs) is proposed on the basis of the differences in thermodynamic stability among different DMDBT isomers. Another maturity index(TMDBT-I2) based on TMDBTs is also suggested on the basis of our empirical observations and presumed thermodynamic stability of TMDBT isomers. These two newly proposed(2,6 + 3,6)-/1,4-DMDBT ratio and TMDBT-I2 correlate well with MDR(4-/1-methyldibenzothiophene) and 2,4-/1,4-DMDBT ratios, suggesting their common chemical reaction mechanisms and similar behavior with increasing maturity. Therefore, they can be effectively applied for maturity assessments. Furthermore, the TMDBTs related maturity parameters are more reliable for over-mature oils and condensates due to the relatively higher concentrations of thermodynamically unstable TMDBT isomers, i.e. 1,4,6-, 1,4,8- and 3,4,6-TMDBT in this study than those of 1-methyldibenzothiophene(1-MDBT) or 1,4-DMDBT. In contrast with 4,6-/1,4-DMDBT, the newly proposed(2,6 + 3,6)-/1,4-DMDBT ratios for oils that originated from different types of source rocks have approximately same relationship with the oil maturity(Rc %). This suggests that the lithology and organic facies may have relatively less influence on(2,6 + 3,6)-/1,4-DMDBT ratio compared to 4,6-/1,4-DMDBT. The maturity parameters based on methylated dibenzothiophenes are particularly useful in the maturity assessments of post- and over-mature oils and condensates and can complement maturity indicators based on steranes and terpanes.展开更多
V2O3 nanoparticles with high surface area have been successfully prepared by a new solvothermal method without using any surfactant and template. The size of V2O3 nanoparticles is mostly equal to 10 nm-30 nm. The high...V2O3 nanoparticles with high surface area have been successfully prepared by a new solvothermal method without using any surfactant and template. The size of V2O3 nanoparticles is mostly equal to 10 nm-30 nm. The highest surface area of obtained V2O3 nanoparticles reaches 49 m2/g. Several kinds of V2O3 catalysts were prepared by different methods. All these V2O3 catalysts obtained thereby showed high catalytic activity for oxidative desulfurization(ODS) reaction by using tert-butyl hydroperoxide as the oxidant. The V2O3 catalyst with a highest ODS activity was obtained under the following conditions: The catalyst was prepared upon using V2O5 as the vanadium source, methanol as the solvent, and oxalic acid as the complexing reagent at a V2O5/oxalic acid molar ratio of 1:2. The process for ODS of dibenzothiophene was carried out under mild conditions(under atmospheric pressure and at a relatively low temperature). The highest ODS activity of the obtained V2O3 nanoparticles can be attributed to their highest surface area.展开更多
Five bacterial strains,which are able to grow and to disintegrate dibenzothiophene (DBT) and dibenzothiophene sulfone (DBTO2) in fossil fuels,are isolated.Analysis of products of DBT metabolized by these strains shows...Five bacterial strains,which are able to grow and to disintegrate dibenzothiophene (DBT) and dibenzothiophene sulfone (DBTO2) in fossil fuels,are isolated.Analysis of products of DBT metabolized by these strains shows that different bacteria strains oxidize DBT by different pathways.The isolated strains R-6,R-16,R-9 and R-8 can metabolize DBT to DBTO2 and 2-hydroxybiphenyl(HBP),which are identified as Bacillus brevis,Bacillus sphaericus,Nocardia globerula and Pseudomonas delafieldii respectively.Another strain R-12 identified as Pseudomonas sp. can degrade DBT completely but it cannot produce DBTO2 and HBP. The optimum temperature and initial pH for desulfurization by R-8 are 32℃ and 7.02 respectively and pH of the broth decreases during biodegradation.The growth of strain R-8 with different sulfur-sources indicates that this strain in DBT medium has an induction period of 3 days,which is longer than those with dimethylsulfoxide and MgSO4 media,but the growth rate of the bacterial strain in DBT is higher after the induction.Higher growth and desulfurization rates are observed in the DBT-hexadecane system than in both DBT-ethanol and DBT-dimethylformamide systems.Both strains of R-8 and R-9 also show higher desulfurization activities toward other sulfur-substrates,indicating that they have greater desulfurization potential in application.展开更多
Highly active MCM-41 supported nickel phosphide catalysts for hydrodesulfurization(HDS) were synthesized by two different phosphorus sources, in which the surface of Ni_2P catalysts were modified by air instead of bei...Highly active MCM-41 supported nickel phosphide catalysts for hydrodesulfurization(HDS) were synthesized by two different phosphorus sources, in which the surface of Ni_2P catalysts were modified by air instead of being passivated by O_2/N_2 mixture. In addition, the catalysts need not be activated with flowing H_2(30 ml·min^(-1))at 500 °C for 2 h prior to reaction as traditional method. X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS), N_2-adsorption specific surface area measurements and CO chemisorption were used to characterize the resulting catalysts. The effect of modification with air on the surface of the catalysts for HDS performance was investigated. Results showed that the surface modification with air can promote the formation of smaller Ni_2P particles and more active Ni sites on surface of catalysts. At 3.0 MPa and 613 K, the dibenzothiophene(DBT)conversion of the catalysts modified with air was 98.7%, which was 7.1% higher than that of catalyst passivated by O_2/N_2 mixture. The higher activities of Ni_2P(x)/M41-O catalysts can be attributed to the smaller Ni_2P particles sizes and the increased hydrogen dissociation activity due to the surface modification.展开更多
Adsorption properties of dibenzothiophene (DBT) on a CNT (carbon nanotube) support as well as on CoMoS/CNT and CoMoO/CNT catalysts have been studied. Consecutive desorption of adsorbates was measured by TGA. The commo...Adsorption properties of dibenzothiophene (DBT) on a CNT (carbon nanotube) support as well as on CoMoS/CNT and CoMoO/CNT catalysts have been studied. Consecutive desorption of adsorbates was measured by TGA. The commonly used carriers AC (activated carbon), γ-Al2O3, and their supported catalysts (CoMoO/AC, CoMoS/AC, CoMoO/γ-Al2O3, CoMoS/γ-Al2O3) were also subjected to analysis for comparison. The acidic properties of the samples were characterized using the NH3-TPD technique.Correlation between the adsorption of DBT and the acidic properties of the catalysts has been established.It was found that the Co-Mo catalysts in the sulfide state adsorbed much more DBT molecules than the corresponding Co-Mo catalysts in the oxide state. The CoMoS/CNT catalyst exhibited very high HDS activity and selectivity, as compared with the CoMoS/γ-Al2O3 catalysts. Based on the BET data and the high hydrogenolysis/hydrogenation selectivity of the CoMoS/CNT, it was deduced that more than90% of the DBT molecules adsorbed on the CoMoS/CNT with an end-on mode, and the surface of the CoMoS/CNT catalyst was almost fully covered with DBT molecules. Although the AC support had very high surface area and high loading ability, the AC supported CoMoS catalyst showed lower HDS activity,as compared with the CoMoS/γ-Al2O3 catalyst.展开更多
This work reports the enhancing effect of a highly cost effective and efficient metal, Fe, incorporation to Co or Ni based Mo/Al_2O_3 catalysts in the oxidative desulfurization(ODS) of dibenzothiophene(DBT) using H_2O...This work reports the enhancing effect of a highly cost effective and efficient metal, Fe, incorporation to Co or Ni based Mo/Al_2O_3 catalysts in the oxidative desulfurization(ODS) of dibenzothiophene(DBT) using H_2O_2 and formic acid as oxidants. The influence of operating parameters i.e. reaction time, catalyst dose, reaction temperature and oxidant amount on oxidation process was investigated. Results revealed that 99% DBT conversion was achieved at 60 °C and 150 min reaction time over Fe–Ni–Mo/Al_2O_3. Fe tremendously enhanced the ODS activity of Co or Ni based Mo/Al_2O_3 catalysts following the activity order: Fe–Ni–Mo/Al_2O_3 NFe–Co–Mo/Al_2O_3 NNi–Mo/Al_2O_3 NCo–Mo/Al_2O_3, while H_2O_2 exhibited higher oxidation activity than formic acid over all catalyst systems. Insight about the surface morphology and textural properties of fresh and spent catalysts were achieved using scanning electron microscopy(SEM), X-ray diffraction(XRD), energy dispersive X-ray(EDX)analysis, Atomic Absorption Spectroscopy(AAS) and BET surface area analysis, which helped in the interpretation of experimental data. The present study can be deemed as an effective approach on industrial level for ODS of fuel oils crediting to its high efficiency, low process/catalyst cost, safety and mild operating condition.展开更多
Two novel V-shaped symmetric chromophores: E-2,8-bis(4-vinyl-4-carbazol-9-yl)diben- zothiophene (abbreviated as SK-G1) and E-2,8-bis(4-vinyl-4-triphenylamino) dibenzothiophene (abbreviated as ST-G1) have been synthesi...Two novel V-shaped symmetric chromophores: E-2,8-bis(4-vinyl-4-carbazol-9-yl)diben- zothiophene (abbreviated as SK-G1) and E-2,8-bis(4-vinyl-4-triphenylamino) dibenzothiophene (abbreviated as ST-G1) have been synthesized and characterized. Their two photon absorption properties were measured by the open-aperture femtosecond Z-scan technique and the nanosecond nonlinear optical transmission (NLT), respectively, when pumped by Ti: sapphire laser at 750 nm and 800 nm.展开更多
基金This research was supported by the Science Foundation of China University of Petroleum-Beijing(No.2462023QNXZ002)the National Key R&D Program of China(2021YFA1501201)+2 种基金the National Natural Science Foundation of China(No.22278174)Independent research project of State Key Laboratory of heavy oil(2021–01)Shandong Excellent Young Scientists Fund Program(Overseas,2022HWYQ-082).
文摘A novel composite material(TD)composed of TS-1 microcrystalline and dendritic mesoporous silica nanospheres(DMSNs)was successfully prepared.The TD composite material had open pore structure and large specific surface area,which was conducive to the mass transfer of reactants and products.The Ti element in TS-1 could be used as an electron assistant,and the spillover d-electrons were conducive to the improvement of the sulfidation and dispersion of MoS_(2),thereby forming more type II MoS_(2) active phases.The incorporation of Ti could bring more Brønsted(B)and Lewis(L)acid,which was conducive to the hydrogenation pathway(HYD)selectivity(41.2%)of dibenzothiophene(DBT)hydrodesulfurization(HDS)and isomerization(ISO)route selectivity(21.9%)of 4,6-dimethyldibenzothiophene(4,6-DMDBT)HDS,thus improve the HDS activity of DBT and 4,6-DMDBT.NiMo/TD-70(Aging temperature=70℃)had the best HDS activities of DBT(99.0%)and 4,6-DMDBT(93.7%)due to its large open pore structure,good acidity,suitable metal-support interaction(MSI)and perfect dispersion of the metallic active sites.
基金supported by the Science and Technology Project of Zhejiang Province(2016C33039)the Public Technology Research Project(Analysis and Measurement)of Zhejiang Province(LGC19B070004)+1 种基金State Key Laboratory of Environmental Chemistry and Ecotoxicology,Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences(KF2018-15)Natural Science Foundation of Zhejiang Province(LY18C030003)
文摘Polychlorinated dibenzothiophenes(PCDTs)and their corresponding sulfone(PCDTO2)compounds are a group of important persistent organic pollutants.In the present study,geometrical optimization and subsequent calculations of electrostatic potentials(ESPs)on molecular surface have been performed for all 135 PCDTs and 135 PCDTO2 congeners at the HF/6-31G*level of theory.A number of statistically-based parameters have been extracted.Linear relationship between gas-chromatographic retention index(RI)and the structural descriptors have been established by multiple linear regression.The result shows that two descriptors derived from positive electrostatic potential on molecular surface,σ+^2 andπ,together with the molecular volume(Vmc)and the energy of the lowest unoccupied molecular orbital(ELUMO)can be well used to express the quantitative structure-retention relationship(QSRR)of PCDTs and PCDTO2.Predictive capability of the two models has been demonstrated by leave-one-out cross-validation with the cross-validated correlation coefficient(RCV)of 0.996 and 0.997,respectively.Furthermore,the predictive power of the models is further examined for the external test set.Correlation coefficients(R)between the observed and predicted RI values for the external test set are 0.997 and0.998,respectively,validating the robustness and good prediction of our model.The QSRR model established may provide again a powerful method for predicting chromatographic properties of aromatic organosulfur compounds.
基金financially supported by the Program for Liaoning Excellent Talents in University,abbreviated as“LNET”(LJQ2015062)Program for Science and Technology Agency of Liaoning Province(20170540585)+1 种基金General Scientific Research Project of Liaoning Provincial Department of Education(L2015296,L2016018)Science and Technology Planning project of Fushun(FSKJHT201376)
文摘By using the bimodal mesoporous silica(BMMS) as the carrier and butyl titanate as the titanium source, the TiO_2/BMMS catalyst was prepared. The samples were characterized by XRD, XRF, N_2 adsorption and desorption, FTIR, UVvis,SEM, EDS, and TEM techniques. The test results showed that TiO_2 was amorphous, the TiO_2/BMMS catalyst had an ordered bimodal mesoporous structure, and the chemical interaction existed between BMMS and TiO_2. Since the TiO_2/BMMS had a lower band gap, its photocatalytic activity was better than TiO_2. Under UV irradiation a one-pot PODS system was set up, using TiO_2/BMMS as the catalyst, H_2O_2 as the oxidant, and methanol as the solvent. The TiO_2/BMMS catalyst showed better photocatalytic activity than the mono-modal mesoporous TiO_2/SBA-15 catalyst, and the desulfurization rate of dibenzothiophene(DBT) over TiO_2/BMMS catalyst could reach 99._2%. The TiO_2/BMMS catalyst also had so good stability that the desulfurization rate of DBT did not drop apparently after 8 cycles of reusing, and could still be close to 90%.
基金financially supported by the National Natural Science Foundation of China (Nos. 21576122, 21646001, 21506080)Natural Science Foundation of Jiangsu Province (Nos. BK20150485, BK20170528)+2 种基金China Postdoctoral Science Foundation (2017M611727)Jiangsu Planned Projects for Postdoctoral Research Funds (1701104B)supported by the Student Innovation and Entrepreneurship Training Program (201810299332 W)
文摘Supported ionic liquid(IL) catalysts [C_nmim]_3PMo_(12)O_(40)/Am TiO_2(amorphous TiO_2) were synthesized through a one-step method for extraction coupled catalytic oxidative desulfurization(ECODS) system. Characterizations such as FTIR, DRS,wide-angle XRD, N_2 adsorption–desorption and XPS were applied to analyze the morphology and Keggin structure of the catalysts. In ECODS with hydrogen peroxide as the oxidant, it was found that ILs with longer alkyl chains in the cationic moiety had a better effect on the removal of dibenzothiophene. The desulfurization could reach 100% under optimal conditions, and GC–MS analysis was employed to detect the oxidized product after the reaction. Factors affecting the desulfurization efficiencies were discussed, and a possible mechanism was proposed. In addition, cyclic experiments were also conducted to investigate the recyclability of the supported catalyst. The catalytic activity of [C_(16)mim]_3 PMo_(12)O_(40)/Am TiO_2 only dropped from 100% to 92.9% after ten cycles, demonstrating the good recycling performance of the catalyst and its potential industrial application.
基金support provided by the Fundamental Research Funds for the Central Universities (No. 12CX06043A) of Chinathe Key Laboratory of Marine Spill Oil Identification and Damage Assessment Technology,SOA(No. 201407)
文摘In this research, the degradation of dibenzothiophene(DBT) was investigated by using Pseudomonas sp. LKY-5 isolated from oil contaminated soil. The response surface methodology(RSM) based on the Box-Behnken design(BBD) was applied for evaluating the interactive effects of four independent variables including substrate concentration, temperature, pH and agitation rate on the DBT removal response. A total of 29 experiments for four factors at three levels were conducted in present study. A second-order regression model was then developed, and the analysis of variance(ANOVA) illustrated that the proposed quadratic model could be utilized to navigate the design space. The value of determination coefficient(R2=0.953 4) indicated a satisfactory agreement between the quadratic model and the experimental data. It was found that DBT removal was more significantly affected(P<0.000 1) by substrate concentration compared with other three parameters. An 100% degradation of DBT could be obtained by Pseudomonas sp. LKY-5 at a substrate concentration of 100 mg/L.
基金the Undergraduate Innovation and Entrepreneurship Training Project (201710057009) for providing funding and support for this research
文摘The potential of carrying out oxidative desulfurization(ODS) using oxygen as an oxidant was explored in this work. n-Octane firstly reacted with oxygen to produce hydroperoxides in-situ, which were then used as oxidants to oxidize the dibenzothiophene(DBT) in the absence of catalysts. The hydroperoxides generated in-situ were effective in oxidizing DBT to its corresponding dibenzothiophene sulfone(DBTO_2) which was characterized by FT-IR and ~1H-NMR. The removal rate of DBT could reached 98.4% under conditions covering a temperaure of 140℃, a rection duration of 4 h, and an oxygen partial pressure of 0.4 MPa. The influences of different hydrocarbon components in diesel on DBT removal were investigated. The results showed that cyclohexane and n-dodecane had no effect on the removal of DBT, but xylene had a slight negative effect on DBT removal. A possible oxidation mechanism was proposed and the concentration of hydroperoxides in both O_2-oxidized octane and model diesel were detected.
文摘In this research,1-butyl-pyridinium tetrafluoroborate([C4Py][BF4]-)was prepared by ion exchange method and was characterized by1H-NM R,13C-NM R,and FT-IR techniques.The synthesized ionic liquid w as used for removal of dibenzothiophene as a typical organosulfur pollutant from organic medium.The effect of different parameters on the extraction efficiency w as studied and optimized.At the optimized conditions,97.68%of dibenzothiophene w as extracted from 1 000 mg/L n-hexane solution.The extraction efficiency obtained in this w ork w as higher than the previous reported values.The desulfurization reaction w as kinetically follow ed the second order mechanism.The ionic liquid w as reusable and after four regeneration cycles 97%of its original extraction efficiency w as retained.
文摘The aim of the current work is to synthesize the new heterocyclic pentacyclic condensed systems that combine benzothiophen and benzimidazole/triazole into one molecule. The dibenzothiophene was taken as an initial compound and by consistent “extension” was annihilated the imidazole and triazole nucleuses. As a result two new pentacyclic systems were produced: 3H-, 7H-diimidazole[4,5-b][5,4-g] dibenzothiophene-5,5-dioxide and 3H-, 7H-ditriazole[4,5-b][5,4-g] dibenzothiophene-5,5-dioxide with the promising antimi-crobial activity. Their spectral characteristics were studied.
文摘Density functional methods have been used for the calculation of electronic structures, electronic transitions, vertical electron affinities and intermolecular reorganization energies for tri-aryl substituted dibenzothiophenes. These model compounds were then compared to the predicted values for dibenzo[b,d]thiophen-2-yltriphenylsilane (DBTSI 2) and to dibenzo[b,d]thiophene-2,8-diylbis(diphenylphosphine oxide) (PO15), known electron transport molecules. The results indicate that these model compounds can be used in a blue OLED system.
文摘In this work, the possibility of enhanced activity during the hydrodesulfurization of dibenzothiophene over certain nano-MoS<sub>2</sub> catalyst due to the presence of H<sub>2</sub>S was examined by focusing on the reaction kinetics. With H<sub>2</sub>S generated <i>in situ</i>, the overall reaction followed the autocatalytic rate law;while in the absence of H<sub>2</sub>S the kinetics indicated a pseudo-first-order reaction. H<sub>2</sub>S appears to modify the relative contributions of parallel hydrogenation and desulfurization reactions by drastically increasing the hydrogenation rate. Kinetic models were developed that describe the hydrodesulfurization reaction at various H<sub>2</sub>S concentrations, and the kinetic parameters and adsorption equilibrium constants associated with this process were estimated by fitting the experimental data. The results suggest that the promotion and/or inhibition of hydrodesulfurization by H<sub>2</sub>S likely result from the same overall reaction mechanism.
文摘Sulfur emission through fuel combustion is a global problem because it is a major cause of acid rain. Crud oil contains many heterocyclic organic sulfur compounds, among which dibenzothiophene(DBT) and DBTs bearing alkyl substitutions usually are representative compounds. A strain was isolated from refinery sludge and identified as Corynebacterium ZD-1. The behavior of DBT degradation by ZD-1 in aqueous phase was investigated. Corynebacterium ZD-1 could metabolize DBT to 2-hydroxybiphenyl(2-HBP) as the dead-end metabolite through a sulfur-specific pathway. In shake flask culture, ZD-1 had its maximal desulfurization activity in the late exponential growth phase and the specific production rate of 2-HBP was about 0.14(mmol·kg dry cell -1·min -1, mmol·KDC -1·min -1). Active resting cells for desulfurization should be prepared only in this period. 2-HBP inhibited the growth of strain ZD-1, the production of DBT degradation enzymes, and the activity of enzymes. Sulfate inhibited the production of dibenzothiophene(DBT) degradation enzymes but had no effect on the enzymes’ activity. The production rates of 2-HBP at lower cell densities were higher and the maximum amount conversion of DBT to 2-HBP(0.067 mmol/L) after 8 h was gained at 9.2 g dry cell/L rather higher cell density. The results indicated that this newly isolated strain could be a promising biocatalyst for DBT desulfurization.
基金funded by the National Natural Science Foundation of China (Grant No. 41272158)the State Key Laboratory of Petroleum Resources and Prospecting (PRP/indep-2-1302)
文摘Aromatic fractions of 140 oils and condensates that originated from different types of source rocks(marine shale, terrestrial shale and marine carbonate) were analyzed using gas chromatography–mass spectrometry(GC–MS) to investigate the relative distributions of methylated dibenzothiophenes with respect to thermal maturity. The positions of methyl groups of trimethyldibenzothiophene isomers(TMDBTs) including those used in the definition of maturity indicator TMDBT index in previous studies were firmly identified by co-elution of internal standards in GC–MS analysis and by comparing with reported retention indices. A new maturity ratio related to dimethyldibenzothiophenes(DMDBTs) is proposed on the basis of the differences in thermodynamic stability among different DMDBT isomers. Another maturity index(TMDBT-I2) based on TMDBTs is also suggested on the basis of our empirical observations and presumed thermodynamic stability of TMDBT isomers. These two newly proposed(2,6 + 3,6)-/1,4-DMDBT ratio and TMDBT-I2 correlate well with MDR(4-/1-methyldibenzothiophene) and 2,4-/1,4-DMDBT ratios, suggesting their common chemical reaction mechanisms and similar behavior with increasing maturity. Therefore, they can be effectively applied for maturity assessments. Furthermore, the TMDBTs related maturity parameters are more reliable for over-mature oils and condensates due to the relatively higher concentrations of thermodynamically unstable TMDBT isomers, i.e. 1,4,6-, 1,4,8- and 3,4,6-TMDBT in this study than those of 1-methyldibenzothiophene(1-MDBT) or 1,4-DMDBT. In contrast with 4,6-/1,4-DMDBT, the newly proposed(2,6 + 3,6)-/1,4-DMDBT ratios for oils that originated from different types of source rocks have approximately same relationship with the oil maturity(Rc %). This suggests that the lithology and organic facies may have relatively less influence on(2,6 + 3,6)-/1,4-DMDBT ratio compared to 4,6-/1,4-DMDBT. The maturity parameters based on methylated dibenzothiophenes are particularly useful in the maturity assessments of post- and over-mature oils and condensates and can complement maturity indicators based on steranes and terpanes.
基金supported by the National Nature Science Foundation of China (21303088)
文摘V2O3 nanoparticles with high surface area have been successfully prepared by a new solvothermal method without using any surfactant and template. The size of V2O3 nanoparticles is mostly equal to 10 nm-30 nm. The highest surface area of obtained V2O3 nanoparticles reaches 49 m2/g. Several kinds of V2O3 catalysts were prepared by different methods. All these V2O3 catalysts obtained thereby showed high catalytic activity for oxidative desulfurization(ODS) reaction by using tert-butyl hydroperoxide as the oxidant. The V2O3 catalyst with a highest ODS activity was obtained under the following conditions: The catalyst was prepared upon using V2O5 as the vanadium source, methanol as the solvent, and oxalic acid as the complexing reagent at a V2O5/oxalic acid molar ratio of 1:2. The process for ODS of dibenzothiophene was carried out under mild conditions(under atmospheric pressure and at a relatively low temperature). The highest ODS activity of the obtained V2O3 nanoparticles can be attributed to their highest surface area.
基金Supported by the special funds for major state basic research project (No.G2000048004) and SINOPEC.
文摘Five bacterial strains,which are able to grow and to disintegrate dibenzothiophene (DBT) and dibenzothiophene sulfone (DBTO2) in fossil fuels,are isolated.Analysis of products of DBT metabolized by these strains shows that different bacteria strains oxidize DBT by different pathways.The isolated strains R-6,R-16,R-9 and R-8 can metabolize DBT to DBTO2 and 2-hydroxybiphenyl(HBP),which are identified as Bacillus brevis,Bacillus sphaericus,Nocardia globerula and Pseudomonas delafieldii respectively.Another strain R-12 identified as Pseudomonas sp. can degrade DBT completely but it cannot produce DBTO2 and HBP. The optimum temperature and initial pH for desulfurization by R-8 are 32℃ and 7.02 respectively and pH of the broth decreases during biodegradation.The growth of strain R-8 with different sulfur-sources indicates that this strain in DBT medium has an induction period of 3 days,which is longer than those with dimethylsulfoxide and MgSO4 media,but the growth rate of the bacterial strain in DBT is higher after the induction.Higher growth and desulfurization rates are observed in the DBT-hexadecane system than in both DBT-ethanol and DBT-dimethylformamide systems.Both strains of R-8 and R-9 also show higher desulfurization activities toward other sulfur-substrates,indicating that they have greater desulfurization potential in application.
基金Supported by the National Natural Science Foundation of China(21276048)the Project of Education Department of Heilongjiang Province,China(12541060)the Graduate Innovation Project of Northeast Petroleum University,China(YJSCX2016-019NEPU)
文摘Highly active MCM-41 supported nickel phosphide catalysts for hydrodesulfurization(HDS) were synthesized by two different phosphorus sources, in which the surface of Ni_2P catalysts were modified by air instead of being passivated by O_2/N_2 mixture. In addition, the catalysts need not be activated with flowing H_2(30 ml·min^(-1))at 500 °C for 2 h prior to reaction as traditional method. X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS), N_2-adsorption specific surface area measurements and CO chemisorption were used to characterize the resulting catalysts. The effect of modification with air on the surface of the catalysts for HDS performance was investigated. Results showed that the surface modification with air can promote the formation of smaller Ni_2P particles and more active Ni sites on surface of catalysts. At 3.0 MPa and 613 K, the dibenzothiophene(DBT)conversion of the catalysts modified with air was 98.7%, which was 7.1% higher than that of catalyst passivated by O_2/N_2 mixture. The higher activities of Ni_2P(x)/M41-O catalysts can be attributed to the smaller Ni_2P particles sizes and the increased hydrogen dissociation activity due to the surface modification.
文摘Adsorption properties of dibenzothiophene (DBT) on a CNT (carbon nanotube) support as well as on CoMoS/CNT and CoMoO/CNT catalysts have been studied. Consecutive desorption of adsorbates was measured by TGA. The commonly used carriers AC (activated carbon), γ-Al2O3, and their supported catalysts (CoMoO/AC, CoMoS/AC, CoMoO/γ-Al2O3, CoMoS/γ-Al2O3) were also subjected to analysis for comparison. The acidic properties of the samples were characterized using the NH3-TPD technique.Correlation between the adsorption of DBT and the acidic properties of the catalysts has been established.It was found that the Co-Mo catalysts in the sulfide state adsorbed much more DBT molecules than the corresponding Co-Mo catalysts in the oxide state. The CoMoS/CNT catalyst exhibited very high HDS activity and selectivity, as compared with the CoMoS/γ-Al2O3 catalysts. Based on the BET data and the high hydrogenolysis/hydrogenation selectivity of the CoMoS/CNT, it was deduced that more than90% of the DBT molecules adsorbed on the CoMoS/CNT with an end-on mode, and the surface of the CoMoS/CNT catalyst was almost fully covered with DBT molecules. Although the AC support had very high surface area and high loading ability, the AC supported CoMoS catalyst showed lower HDS activity,as compared with the CoMoS/γ-Al2O3 catalyst.
文摘This work reports the enhancing effect of a highly cost effective and efficient metal, Fe, incorporation to Co or Ni based Mo/Al_2O_3 catalysts in the oxidative desulfurization(ODS) of dibenzothiophene(DBT) using H_2O_2 and formic acid as oxidants. The influence of operating parameters i.e. reaction time, catalyst dose, reaction temperature and oxidant amount on oxidation process was investigated. Results revealed that 99% DBT conversion was achieved at 60 °C and 150 min reaction time over Fe–Ni–Mo/Al_2O_3. Fe tremendously enhanced the ODS activity of Co or Ni based Mo/Al_2O_3 catalysts following the activity order: Fe–Ni–Mo/Al_2O_3 NFe–Co–Mo/Al_2O_3 NNi–Mo/Al_2O_3 NCo–Mo/Al_2O_3, while H_2O_2 exhibited higher oxidation activity than formic acid over all catalyst systems. Insight about the surface morphology and textural properties of fresh and spent catalysts were achieved using scanning electron microscopy(SEM), X-ray diffraction(XRD), energy dispersive X-ray(EDX)analysis, Atomic Absorption Spectroscopy(AAS) and BET surface area analysis, which helped in the interpretation of experimental data. The present study can be deemed as an effective approach on industrial level for ODS of fuel oils crediting to its high efficiency, low process/catalyst cost, safety and mild operating condition.
基金the National Natural Science Foundation of China(No.50273024)the Foundation for the Author of National Excellent Doctoral Dissertation of PR China(FANEDD,No 200333)+1 种基金Natural Foundation of Jiangsu Province(No.BK2003031)the Foundation of Jiangsu Province Education Committee(No.03KJB 150115)for financial support.
文摘Two novel V-shaped symmetric chromophores: E-2,8-bis(4-vinyl-4-carbazol-9-yl)diben- zothiophene (abbreviated as SK-G1) and E-2,8-bis(4-vinyl-4-triphenylamino) dibenzothiophene (abbreviated as ST-G1) have been synthesized and characterized. Their two photon absorption properties were measured by the open-aperture femtosecond Z-scan technique and the nanosecond nonlinear optical transmission (NLT), respectively, when pumped by Ti: sapphire laser at 750 nm and 800 nm.
