The solid-liquid equilibria of musk ketone + musk xylene, musk xylene+1,3-dimethyl-2,4-dinitro-5-tert-butyl benzene are measured by differential scanning calorimeter (DSC), these systems are proved to be simple eutect...The solid-liquid equilibria of musk ketone + musk xylene, musk xylene+1,3-dimethyl-2,4-dinitro-5-tert-butyl benzene are measured by differential scanning calorimeter (DSC), these systems are proved to be simple eutectics. Moreover the melting points and the fusion enthalpies of musk ketone, musk xylene and 1,3-dimethyl-2,4-dinitro-5-tert-butyl benzene are also measured by the DSC. These solid-liquid equilibrium data and the heats of fusion are reported for the first time. Then UNIFAC model is used to correlate the solid-liquid equilibrium data.It is shown that the solid-liquid equilibria of musk systems can be predicted bv the UNIFAC model.展开更多
The direct tandem oxidation synthesis of benzenediol from benzene could simplify or even avoid the separation and purification of reaction intermediates, which is promising but challenged because of the further requir...The direct tandem oxidation synthesis of benzenediol from benzene could simplify or even avoid the separation and purification of reaction intermediates, which is promising but challenged because of the further required immediate consecutive activation of intermediate phenol. In this work, a synergistic benzene tandem-oxidation catalyst that V-Cu bimetallic oxides modified nanoporous silica(VCu-NS)was constructed via a facile assembly strategy which involves addictive negative anion citric acid mediating the intercalation of metal-citric acid chelate in mesopore of silica and subsequent thermal calcination inducing dual-metal active site formation. Such a tactic could make amorphous VOxspecies well covered on the surface of mesopore, and ultrafine copper oxide particles surrounded and neighbored by highly dispersed VOxwith strong interplay in mesopore, which was comprehensively confirmed by various characterizations. Benefiting from the unique V-Cu neighboring effect, the desorption of formed phenol over the catalytic site might be restricted therefore easily further activated by the formed reactive oxidative species, 3VCu-NS shows synergetic tandem-oxidation catalytic activities for benzene towards benzenediol with a selectivity of 57%. The result allows optimal 3VCu-NS to be a promising catalyst for benzenediol synthesis from benzene.展开更多
To better understand the benzene alkylation with chloroaluminate ionic liquids(ILs) as catalyst, the interfacial properties between the benzene/butene binary reactants and chloroaluminate ILs with varying cation alkyl...To better understand the benzene alkylation with chloroaluminate ionic liquids(ILs) as catalyst, the interfacial properties between the benzene/butene binary reactants and chloroaluminate ILs with varying cation alkyl chain length and different anions were investigated using molecular dynamics(MD) simulations. The results indicate that ILs can obviously improve the interfacial width, solubility and diffusion of reactants compared to H_(2)SO_(4). The longer alkyl chains of cations present a density enrichment at the interface and protrude into the binary reactants phase. Furthermore, the ILs consisting of 1-octyl-3-methylimidazolium cations([Omim]^(+)) and the stronger acidity heptachlorodialuminate anions([Al_(2)Cl_(7)]^(-)) are more beneficial to promote the interfacial width and facilitate the dissolution and diffusion of benzene in both the IL bulk and the interfacial region in comparison to the ones with shorter alkyl chains cations and weaker acidity anions. The information gives us a better guideline for the design of ILs for benzene alkylation.展开更多
In this work, liquid–liquid equilibria(LLE) data for the ternary system methyl tert-butyl ketone(MTBK)+ o, m,p-benzenediol + water were investigated at 333.2 K, 343.2 K and 353.2 K under 101.3 kPa. The performance of...In this work, liquid–liquid equilibria(LLE) data for the ternary system methyl tert-butyl ketone(MTBK)+ o, m,p-benzenediol + water were investigated at 333.2 K, 343.2 K and 353.2 K under 101.3 kPa. The performance of MTBK to extract o, m, p-benzenediol from wastewaters was estimated by partition coefficients and separation factors. The Hand and Bachman equations were both applied to check the reliability of the experimental LLE data. Furthermore, the Non-Random Two-Liquid(NRTL) and Universal Quasi Chemical(UNIQUAC) models were applied to correlate the measured LLE data. The results showed a good agreement with the determined ternary LLE data with the root-mean-square error(RMSE) values below 0.71%. MTBK was proved to be a promising extracting agent in extracting benzenediols from effluents.展开更多
A series of Cu-based catalysts were developed for alkylation of benzene with syngas. The catalyst samples were prepared by the impregnation method, and were characterized by XRD, XRF, NH3-TPD, and TEM and evaluated in...A series of Cu-based catalysts were developed for alkylation of benzene with syngas. The catalyst samples were prepared by the impregnation method, and were characterized by XRD, XRF, NH3-TPD, and TEM and evaluated in a fixed bed reactor. The optimized reaction temperature of Cu/Al2O3/ZSM-5 catalyst was 350 ℃, while higher contents of copper were conducive to alkylation of benzene with syngas. The new medium strength acid centers in the catalyst created by Cu were beneficial to alkylation. Hydrogenation reaction of CO was executed on the metal centers without dissociation, Dimethyl ether(DME) was the major intermediate over Cu-based catalysts. Higher selectivity of methylation and lower selectivity of heavy aromatics were confirmed after the second metal(Zn, Mn, or V) was added to the copper catalyst. Cu was partly covered by Zn in the Cu-Zn/Al2O3/ZSM-5 catalyst leading to low dispersion and low activity of copper. Cu-Mn/Al2O3/ZSM-5 catalyst possessed the best yield of methylation product. Cu-Mn composite oxides were probably formed in fresh catalyst, which blocked the sintering of Cu in the reaction process. The loading of Cu decreased dramatically after the introduction of V, while causing an increase of the amount of medium strength acid centers at the same time. V prevented the sintering of copper particles during the reducing process and had a promoting effect on the activity of Cu.展开更多
The acidity and acid distribution of hierarchical porous ZSM-5 were tailored via phosphate modification. The catalytic results showed that both benzene conversion and selectivity of toluene and xylene increased with t...The acidity and acid distribution of hierarchical porous ZSM-5 were tailored via phosphate modification. The catalytic results showed that both benzene conversion and selectivity of toluene and xylene increased with the presence of appropriate amount of phosphorus. Meanwhile, side reactions such as methanol to olefins related with the formation of by-product ethylbenzene formation and isomerization of xylene to meta-xylene were suppressed efficiently. The acid strength and sites amount of Br?nsted acid of the catalyst were crucial for improving benzene conversion and yield of xylene, whereas passivation of external surface acid sites played an important role in breaking thermodynamic equilibrium distribution of xylene isomers.展开更多
A novel industrial process was designed for the highly selective production of ethylbenzene. It comprised of a reactor vessel, vapor phase ethylene feed stream, benzene and transalkylation feed stream. Especially the ...A novel industrial process was designed for the highly selective production of ethylbenzene. It comprised of a reactor vessel, vapor phase ethylene feed stream, benzene and transalkylation feed stream. Especially the product stream containing ethylbenzene was used to heat the reactor vessel, which consisted of an alkylation section, an upper heat exchange section, and a bottom heat exchange section. In such a novel reactor, vapor phase benzene and liquid phase benzene were coexisted due to the heat produced by isothermal reaction between the upper heat exchange section and the bottom heat exchange section. The process was demonstrated by the thermodynamic analysis and experimental results. In fact, during the 1010 hour-life-test of gas phase ethene with gas phase-liquid phase benzene alkylation reaction, the ethene conversion was above 95%, and the ethylbenzene selectivity was above 83% (only benzene feed) and even higher than 99% (benzene plus transalkylation feed). At the same time, the xylene content in the ethylbenzene was less than 100 ppm when the reaction was carried out under the reaction conditions of 140-185℃ of temperature, 1.6-2.1 MPa of pressure, 3.0-5.5 of benzene/ethylene mole ratio, 4-6 v% of transalkylation feed/(benzene+transalkylation feed), 0.19-0.27 h^-1 of ethene space velocity, and 1000 g of 3998 catalyst loaded. Thus, compared with the conventional ethylbenzene synthesis route, the transalkylation reactor could be omitted in this novel industrial process.展开更多
The alkylation of benzene with isopropanol over beta-zeolite is a more cost-effective solution to cumene production. During the benzene alkylation cycles, the cumene selectivity slowly increased, while the benzene con...The alkylation of benzene with isopropanol over beta-zeolite is a more cost-effective solution to cumene production. During the benzene alkylation cycles, the cumene selectivity slowly increased, while the benzene conversion presented the sharp decrease due to catalyst deactivation. The deactivation mechanism of betazeolite catalyst was investigated by characterizing the fresh and used catalysts. The XRD, SEM and TEM results show that the crystalline and particle size of the beta-zeolite catalyst almost remained stable during the alkylation cycles. The drop in catalytic activity and benzene conversion could be explained by the TG, BET,NH_3-TPD and GC–MS results. The organic matters mainly consisted of ethylbenzene, p-xylene and 1-ethyl-3-(1-methyl) benzene produced in the benzene alkylation deposited in the catalyst, which strongly reduced the specific surface area of beta-zeolite catalyst. Moreover, during the reaction cycles, the amount of acidity also significantly decreased. As a result, the catalyst deactivation occurred. To maintain the catalytic performance,the catalyst regeneration was carried out by using ethanol rinse and calcination. The deactivated catalyst could be effectively regenerated by the calcination method and the good catalytic performance was obtained.展开更多
The adsorption behavior and description behavior of benzene , ethylene and ethylbenzene over HZSM-5 and Co/HZSM-5 catalysts were studied by means of TPSR (Temperature programmed surface reaction) technique. TPSR resul...The adsorption behavior and description behavior of benzene , ethylene and ethylbenzene over HZSM-5 and Co/HZSM-5 catalysts were studied by means of TPSR (Temperature programmed surface reaction) technique. TPSR results of ben- zene and ethylene co-adsorption show that the maian products are styrene , ethylben- zene, toluene, propane, and butane. In a separate experiment of ethylbenzene ad- sorption, styrene . toluene and benzene are formed due to cracking and dehydro- genation. The mechanism of styrene formation was proposed , i. e. , the reaction was carried out via. the dehydrogenation of mediate species ethylbenzene according to the results of TPSR-MS , activity testing and thermodynamic analysis.展开更多
The effect of La on the performance of a supported RuB amorphous alloy catalyst for benzene selective hydrogenation was studied by means of activity and selectivity tests, such as HRTEM, SAED, XPS, and XRD. The result...The effect of La on the performance of a supported RuB amorphous alloy catalyst for benzene selective hydrogenation was studied by means of activity and selectivity tests, such as HRTEM, SAED, XPS, and XRD. The results show that the addition of La to RuB amorphous alloy catalyst can evidently increase the activity and improve the thermal stability of RuB amorphous alloy to refrain its crystallization. The promoting effect of La on the activity of RuB amorphous alloy catalyst is because of the high dispersion of the active components.展开更多
Ru-based catalysts promoted with Mn and Zn were prepared by a co-precipitation method. In liquid-phase hydrogenation of benzene, the Ru-Mn-Zn catalysts exhibited superior catalytic performance to the catalysts promote...Ru-based catalysts promoted with Mn and Zn were prepared by a co-precipitation method. In liquid-phase hydrogenation of benzene, the Ru-Mn-Zn catalysts exhibited superior catalytic performance to the catalysts promoted with Zn or Mn alone. The optimum Mn/Zn molar ratio was determined to be 0.3. With the addition of 0.5 g NaOH, the Ru-Mn-Zn-0.3 catalyst, which was reduced at 150 ? C, afforded a cyclohexene selectivity of 81.1% at a benzene conversion of 60.2% at 5 min and a maximum cyclohexene yield of 59.9% at 20 min. Based on characterizations, the excellent performance of Ru-Mn-Zn catalyst was ascribed to the suitable pore structure, the appropriate reducibility and the homogenous chemical environment of the catalyst.展开更多
The humidity effects on the benzene decomposition process were investigated by the dielectric barrier discharge(DBD) plasma reactor.The results showed that the water vapor played an important role in the benzene oxi...The humidity effects on the benzene decomposition process were investigated by the dielectric barrier discharge(DBD) plasma reactor.The results showed that the water vapor played an important role in the benzene oxidation process.It was found that there was an optimum humidity value for the benzene removal efficiency,and at around 60% relative humidity(RH),the optimum benzene removal efficiency was achieved.At a SIE of 378 J/L,the removal efficiency was 66% at 0% RH,while the removal efficiency reached 75.3% at 60% RH and dropped to 69% at 80% RH.Furthermore,the addition of water inhibited the formation of ozone and NO2 remarkably.Both of the concentrations of ozone and NO2 decreased with increasing of the RH at the same specific input energy.At a SIE of 256 J/L,the concentrations of ozone and NO2 were 5.4 mg/L and 1791 ppm under dry conditions,whereas they were only 3.4 mg/L and 1119 ppm at 63.5%RH,respectively.Finally,the outlet gas after benzene degradation was qualitatively analyzed by FT-IR and GC-MS to determine possible intermediate byproducts.The results suggested that the byproducts in decomposition of benzene primarily consisted of phenol and substitutions of phenol.Based on these byproducts a benzene degradation mechanism was proposed.展开更多
Ru-Ce catalysts were prepared by a co-precipitation method.The effects of Ce precursors with different valences and Ce contents on the catalytic performance of Ru-Ce catalysts were investigated in the presence of ZnSO...Ru-Ce catalysts were prepared by a co-precipitation method.The effects of Ce precursors with different valences and Ce contents on the catalytic performance of Ru-Ce catalysts were investigated in the presence of ZnSO4.The Ce species in the catalysts prepared with different valences of the Ce precursors all exist as CeO2 on the Ru surface.The promoter CeO2alone could not improve the selectivity to cyclohexene of Ru catalysts.However,almost all the CeO2 in the catalysts could react with the reaction modifier ZnSO4 to form(Zn(OH)2)3(ZnSO4)(H2O)3 salt.The amount of the chemisorbed salt increased with the CeO2 loading,resulting in the decrease of the activity and the increase of the selectivity to cyclohexene of Ru catalyst.The Ru-Ce catalyst with the optimum Ce/Ru molar ratio of 0.19 gave a maximum cyclohexene yield of 57.4%.Moreover,this catalyst had good stability and excellent reusability.展开更多
Preparation of dispersed transition metal oxides catalyst with low oxidation state still remains a challenging task in heterogeneous catalysis.In this study,vanadium oxides supported on zeolite SBA-15 have been prepar...Preparation of dispersed transition metal oxides catalyst with low oxidation state still remains a challenging task in heterogeneous catalysis.In this study,vanadium oxides supported on zeolite SBA-15 have been prepared under hydrothermal condition using V 2 O 5 and oxalic acid as sources of vanadium and reductant,respectively.The structures of samples,especially the oxidation state of vanadium,and the surface distribution of vanadium oxide species,have been thoroughly characterized using various techniques,including N 2-physisorption,X-ray diffraction(XRD),transmission electron microscopy(TEM),X-ray photoelectron spectroscopy(XPS),UV-visible spectra(UV-Vis) and UV-visible-near infrared spectra(UV-Vis-NIR).It is found that the majority of supported vanadium was in the form of vanadium(IV) oxide species with the low valence of vanadium.By adjusting hydrothermal treatment time,the surface distribution of vanadium(IV) oxide species can be tuned from vanadium(IV) oxide cluster to crystallites.These materials have been tested in the hydroxylation of benzene to phenol in liquid-phase with molecular oxygen in the absence of reductant.The catalyst exhibits high selectivity for phenol(61%) at benzene conversion of 4.6%,which is a relatively good result in comparison with other studies employing molecular oxygen as the oxidant.展开更多
The title compound C6H4(C7H5N2)2 was prepared by the condensation of o-phenyl- enediamine with o-phthalic acid and characterized by elemental analysis, IR, UV and H NMR 1 spectra, and its stru...The title compound C6H4(C7H5N2)2 was prepared by the condensation of o-phenyl- enediamine with o-phthalic acid and characterized by elemental analysis, IR, UV and H NMR 1 spectra, and its structure was determined by single-crystal X-ray diffraction. The crystal belongs to orthorhombic system, space group Pbcn with a = 17.928(8), b = 8.828(4), c = 9.752(4)?, Z = 4, V = 1543.4(12) ?3, Dc = 1.336 g/cm3, Mr = 310.35, λ(MoKα) = 0.71073 ?, μ = 0.082 mm-1, F(000) = 648, R = 0.0405 and wR = 0.1092. A total of 1693 unique reflections were collected, of which 1319 with I > 2σ(I) were observed. It is shown that the compound molecule belongs to C2 point group. A one-dimensional chain structure was formed by the intermolecular hydrogen bonds (N(2)–H… N(1)).展开更多
In this work, a novel gas phase silent-packed bed hybrid discharge plasma reactor has been proposed, and its ability to control a simulative gas stream containing 240 ppm benzene is experimentally investigated. In ord...In this work, a novel gas phase silent-packed bed hybrid discharge plasma reactor has been proposed, and its ability to control a simulative gas stream containing 240 ppm benzene is experimentally investigated. In order to optimize the geometry of the reactor, the benzene conversion rate and energy yield (EY) were compared for various inner electrode diameters and quartz tube shapes and sizes. In addition, benzene removal efficiency in different discharge regions was qualitatively analyzed and the gas parameter (space velocity) was systematically studied. It has been found that silent-packed bed hybrid discharge plasma reactor can effectively decompose benzene. Benzene removal proved to achieve an optimum value of 60% with a characteristic energy density of 255 J/L in this paper with a 6 mm bolt high-voltage electrode and a 13 mm quartz tube. The optimal space velocity was 188.1 h^-1, which resulted in moderate energy yield and removal efficiency. Reaction by-products such as hydroquinone, heptanoic acid, 4-nitrocatechol, phenol and 4-phenoxy-phenol were identified by mean of GC-MS. In addition, based on these organic by-products, a benzene destruction pathway was proposed.展开更多
In this paper we take photobacterium phosphoreum (T3) as the experimental bacteria, and determine the half-inhibitory concentration (-1gEC50) against the photobacterium phosphoreum of 16 halogenated benzenes. Usin...In this paper we take photobacterium phosphoreum (T3) as the experimental bacteria, and determine the half-inhibitory concentration (-1gEC50) against the photobacterium phosphoreum of 16 halogenated benzenes. Using B3LYP method of DFT in the Gaussian 03 program, we obtain the structural and thermodynamic descriptors of 16 halogenated benzenes by fully-optimized calculation at the 6-311G** level. Taking the structural and thermodynamic descriptors as theoretical descriptors, the 2D QSAR model (R2 = 0.983) was established, which can be utilized to predict -lgEC50 of halogenated benzene according to the corrected linear solvation energy theory based on the experimental data of-lgECs0. In addition, the relationship between the toxicity and 3D spatial structure of the compound is studied by comparing the molecular similarity index analysis (CoMSIA) of 3D-QSAR method. By cross validation, the correlation coefficient q2 of CoMSIA model is 0.687, and the conventional correlation coefficient R2 = 0.958. The model is stable and reliable with great predictive ability. The 3D-QSAR model shows that the toxicity of halogenated benzene compound is mainly affected by the characteristics of hydrophobie field of the substituted halogens.展开更多
The ZSM-22 and ZSM-35 zeolites were synthesized via the hydrothermal crystallization method. The samples were characterized by XRD, SEM, N_2 adsorption-desorption, NH_3-TPD, TPO, TG, and Raman spectrometry, and the re...The ZSM-22 and ZSM-35 zeolites were synthesized via the hydrothermal crystallization method. The samples were characterized by XRD, SEM, N_2 adsorption-desorption, NH_3-TPD, TPO, TG, and Raman spectrometry, and the results showed that ZSM-22 and ZSM-35 possessed similar microporous volume and acidity. In the alkylation of benzene with methanol, ZSM-22 and ZSM-35 showed different coke location, coking rate and graphitizing degree. Compared with the industrial ZSM-5, ZSM-22 and ZSM-35 both showed higher selectivity of toluene and xylene(93.63% and 96.50%,respectively) during the alkylation of benzene with methanol, and the selectivity of para-xylene in xylene isomers was51.96% and 41.45%, respectively. Meanwhile, the selectivity of ethylbenzene and C_9^+ aromatics was also lower than that of industrial ZSM-5.展开更多
A series of batch experiments were performed using mixed bacterial consortia to investigate biodegradation performance of benzene, toluene, ethylbenzene and three xylene isomers (BTEX) under nitrate, sulfate and fer...A series of batch experiments were performed using mixed bacterial consortia to investigate biodegradation performance of benzene, toluene, ethylbenzene and three xylene isomers (BTEX) under nitrate, sulfate and ferric iron reducing conditions. The results showed that toluene, ethylbenzene, m-xylene and o-xylene could be degraded independently by the mixed cultures coupled to nitrate, sulfate and ferric iron reduction. Under ferric iron reducing conditions the biodegradation of benzene and p-xylene could be occurred only in the presence of other alkylbenzenes. Alkylbenzenes can serve as the primary subs'rates to stimulate the transformation of benzene and p-xylene under anaerobic conditions. Benzene and p-xylene are more toxic than toluene and ethylbenzene, under the three terminal electron acceptors conditions, the degradation rates decreased with toluene 〉 ethylbenzene 〉 m-xylene 〉 o-xylene〉 benzene 〉 p- xylene. Nitrate was a more favorable electron acceptor compared to sulfate and ferric iron. The ratio between sulfate consumed and the loss of benzene, toluene, ethylbenzene, o-xylene, m-xylene, p-xylene was 4.44, 4.51, 4.42, 4.32, 4.37 and 4.23, respectively; the ratio between nitrate consumed and the loss of these substrates was 7.53, 6.24, 6.49, 7.28, 7.81, 7.61, respectively; the ratio between the consumption of ferric iron and the loss of toluene, ethylbenzene, o-xylene, m-xylene was 17.99, 18.04, 18.07, 17.97, respectively.展开更多
文摘The solid-liquid equilibria of musk ketone + musk xylene, musk xylene+1,3-dimethyl-2,4-dinitro-5-tert-butyl benzene are measured by differential scanning calorimeter (DSC), these systems are proved to be simple eutectics. Moreover the melting points and the fusion enthalpies of musk ketone, musk xylene and 1,3-dimethyl-2,4-dinitro-5-tert-butyl benzene are also measured by the DSC. These solid-liquid equilibrium data and the heats of fusion are reported for the first time. Then UNIFAC model is used to correlate the solid-liquid equilibrium data.It is shown that the solid-liquid equilibria of musk systems can be predicted bv the UNIFAC model.
基金financially supported by the National Natural Science Foundation of China (21908085)Natural Science Foundation of Jiangsu Province, China (BK20190961)+1 种基金Postdoctoral Research Foundation of Jiangsu Province (2020Z291)the Jiangsu Provincial Key Laboratory of Environmental Science and Engineering (JSHJZDSYS-202103)。
文摘The direct tandem oxidation synthesis of benzenediol from benzene could simplify or even avoid the separation and purification of reaction intermediates, which is promising but challenged because of the further required immediate consecutive activation of intermediate phenol. In this work, a synergistic benzene tandem-oxidation catalyst that V-Cu bimetallic oxides modified nanoporous silica(VCu-NS)was constructed via a facile assembly strategy which involves addictive negative anion citric acid mediating the intercalation of metal-citric acid chelate in mesopore of silica and subsequent thermal calcination inducing dual-metal active site formation. Such a tactic could make amorphous VOxspecies well covered on the surface of mesopore, and ultrafine copper oxide particles surrounded and neighbored by highly dispersed VOxwith strong interplay in mesopore, which was comprehensively confirmed by various characterizations. Benefiting from the unique V-Cu neighboring effect, the desorption of formed phenol over the catalytic site might be restricted therefore easily further activated by the formed reactive oxidative species, 3VCu-NS shows synergetic tandem-oxidation catalytic activities for benzene towards benzenediol with a selectivity of 57%. The result allows optimal 3VCu-NS to be a promising catalyst for benzenediol synthesis from benzene.
基金The financial support by State Key Laboratory of Heavy Oil Processing, China University of Petroleum。
文摘To better understand the benzene alkylation with chloroaluminate ionic liquids(ILs) as catalyst, the interfacial properties between the benzene/butene binary reactants and chloroaluminate ILs with varying cation alkyl chain length and different anions were investigated using molecular dynamics(MD) simulations. The results indicate that ILs can obviously improve the interfacial width, solubility and diffusion of reactants compared to H_(2)SO_(4). The longer alkyl chains of cations present a density enrichment at the interface and protrude into the binary reactants phase. Furthermore, the ILs consisting of 1-octyl-3-methylimidazolium cations([Omim]^(+)) and the stronger acidity heptachlorodialuminate anions([Al_(2)Cl_(7)]^(-)) are more beneficial to promote the interfacial width and facilitate the dissolution and diffusion of benzene in both the IL bulk and the interfacial region in comparison to the ones with shorter alkyl chains cations and weaker acidity anions. The information gives us a better guideline for the design of ILs for benzene alkylation.
基金Supported by the State Key Laboratory of Pulp and Paper Engineering in China(201703,201708)
文摘In this work, liquid–liquid equilibria(LLE) data for the ternary system methyl tert-butyl ketone(MTBK)+ o, m,p-benzenediol + water were investigated at 333.2 K, 343.2 K and 353.2 K under 101.3 kPa. The performance of MTBK to extract o, m, p-benzenediol from wastewaters was estimated by partition coefficients and separation factors. The Hand and Bachman equations were both applied to check the reliability of the experimental LLE data. Furthermore, the Non-Random Two-Liquid(NRTL) and Universal Quasi Chemical(UNIQUAC) models were applied to correlate the measured LLE data. The results showed a good agreement with the determined ternary LLE data with the root-mean-square error(RMSE) values below 0.71%. MTBK was proved to be a promising extracting agent in extracting benzenediols from effluents.
文摘A series of Cu-based catalysts were developed for alkylation of benzene with syngas. The catalyst samples were prepared by the impregnation method, and were characterized by XRD, XRF, NH3-TPD, and TEM and evaluated in a fixed bed reactor. The optimized reaction temperature of Cu/Al2O3/ZSM-5 catalyst was 350 ℃, while higher contents of copper were conducive to alkylation of benzene with syngas. The new medium strength acid centers in the catalyst created by Cu were beneficial to alkylation. Hydrogenation reaction of CO was executed on the metal centers without dissociation, Dimethyl ether(DME) was the major intermediate over Cu-based catalysts. Higher selectivity of methylation and lower selectivity of heavy aromatics were confirmed after the second metal(Zn, Mn, or V) was added to the copper catalyst. Cu was partly covered by Zn in the Cu-Zn/Al2O3/ZSM-5 catalyst leading to low dispersion and low activity of copper. Cu-Mn/Al2O3/ZSM-5 catalyst possessed the best yield of methylation product. Cu-Mn composite oxides were probably formed in fresh catalyst, which blocked the sintering of Cu in the reaction process. The loading of Cu decreased dramatically after the introduction of V, while causing an increase of the amount of medium strength acid centers at the same time. V prevented the sintering of copper particles during the reducing process and had a promoting effect on the activity of Cu.
基金Supported by the National Natural Science Foundation of China(21476207,21506189)Zhejiang Postdoctoral Research Funded Projects(BSH1502147)
文摘The acidity and acid distribution of hierarchical porous ZSM-5 were tailored via phosphate modification. The catalytic results showed that both benzene conversion and selectivity of toluene and xylene increased with the presence of appropriate amount of phosphorus. Meanwhile, side reactions such as methanol to olefins related with the formation of by-product ethylbenzene formation and isomerization of xylene to meta-xylene were suppressed efficiently. The acid strength and sites amount of Br?nsted acid of the catalyst were crucial for improving benzene conversion and yield of xylene, whereas passivation of external surface acid sites played an important role in breaking thermodynamic equilibrium distribution of xylene isomers.
基金This work is supported by the National 973 Project of China (2009CB623501)
文摘A novel industrial process was designed for the highly selective production of ethylbenzene. It comprised of a reactor vessel, vapor phase ethylene feed stream, benzene and transalkylation feed stream. Especially the product stream containing ethylbenzene was used to heat the reactor vessel, which consisted of an alkylation section, an upper heat exchange section, and a bottom heat exchange section. In such a novel reactor, vapor phase benzene and liquid phase benzene were coexisted due to the heat produced by isothermal reaction between the upper heat exchange section and the bottom heat exchange section. The process was demonstrated by the thermodynamic analysis and experimental results. In fact, during the 1010 hour-life-test of gas phase ethene with gas phase-liquid phase benzene alkylation reaction, the ethene conversion was above 95%, and the ethylbenzene selectivity was above 83% (only benzene feed) and even higher than 99% (benzene plus transalkylation feed). At the same time, the xylene content in the ethylbenzene was less than 100 ppm when the reaction was carried out under the reaction conditions of 140-185℃ of temperature, 1.6-2.1 MPa of pressure, 3.0-5.5 of benzene/ethylene mole ratio, 4-6 v% of transalkylation feed/(benzene+transalkylation feed), 0.19-0.27 h^-1 of ethene space velocity, and 1000 g of 3998 catalyst loaded. Thus, compared with the conventional ethylbenzene synthesis route, the transalkylation reactor could be omitted in this novel industrial process.
基金Supports by the National Key Research and Development Plan(2016YFB0301503)the Jiangsu Natural Science Foundation for Distinguished Young Scholars(BK20150044)+3 种基金the National Natural Science Foundation of China(91534110,21606124)the Natural Science Foundation of the Higher Education Institutions of Jiangsu Province(14KJB530004)the Foundation from State Key Laboratory of Materials-Oriented Chemical Engineering(ZK201402,ZK201407)the Technology Innovation Foundation for Science and Technology Enterprises in Jiangsu Province(BC2015008)
文摘The alkylation of benzene with isopropanol over beta-zeolite is a more cost-effective solution to cumene production. During the benzene alkylation cycles, the cumene selectivity slowly increased, while the benzene conversion presented the sharp decrease due to catalyst deactivation. The deactivation mechanism of betazeolite catalyst was investigated by characterizing the fresh and used catalysts. The XRD, SEM and TEM results show that the crystalline and particle size of the beta-zeolite catalyst almost remained stable during the alkylation cycles. The drop in catalytic activity and benzene conversion could be explained by the TG, BET,NH_3-TPD and GC–MS results. The organic matters mainly consisted of ethylbenzene, p-xylene and 1-ethyl-3-(1-methyl) benzene produced in the benzene alkylation deposited in the catalyst, which strongly reduced the specific surface area of beta-zeolite catalyst. Moreover, during the reaction cycles, the amount of acidity also significantly decreased. As a result, the catalyst deactivation occurred. To maintain the catalytic performance,the catalyst regeneration was carried out by using ethanol rinse and calcination. The deactivated catalyst could be effectively regenerated by the calcination method and the good catalytic performance was obtained.
文摘The adsorption behavior and description behavior of benzene , ethylene and ethylbenzene over HZSM-5 and Co/HZSM-5 catalysts were studied by means of TPSR (Temperature programmed surface reaction) technique. TPSR results of ben- zene and ethylene co-adsorption show that the maian products are styrene , ethylben- zene, toluene, propane, and butane. In a separate experiment of ethylbenzene ad- sorption, styrene . toluene and benzene are formed due to cracking and dehydro- genation. The mechanism of styrene formation was proposed , i. e. , the reaction was carried out via. the dehydrogenation of mediate species ethylbenzene according to the results of TPSR-MS , activity testing and thermodynamic analysis.
文摘The effect of La on the performance of a supported RuB amorphous alloy catalyst for benzene selective hydrogenation was studied by means of activity and selectivity tests, such as HRTEM, SAED, XPS, and XRD. The results show that the addition of La to RuB amorphous alloy catalyst can evidently increase the activity and improve the thermal stability of RuB amorphous alloy to refrain its crystallization. The promoting effect of La on the activity of RuB amorphous alloy catalyst is because of the high dispersion of the active components.
文摘Ru-based catalysts promoted with Mn and Zn were prepared by a co-precipitation method. In liquid-phase hydrogenation of benzene, the Ru-Mn-Zn catalysts exhibited superior catalytic performance to the catalysts promoted with Zn or Mn alone. The optimum Mn/Zn molar ratio was determined to be 0.3. With the addition of 0.5 g NaOH, the Ru-Mn-Zn-0.3 catalyst, which was reduced at 150 ? C, afforded a cyclohexene selectivity of 81.1% at a benzene conversion of 60.2% at 5 min and a maximum cyclohexene yield of 59.9% at 20 min. Based on characterizations, the excellent performance of Ru-Mn-Zn catalyst was ascribed to the suitable pore structure, the appropriate reducibility and the homogenous chemical environment of the catalyst.
基金supported by National Natural Science Foundation of China(Nos.11205007 and 11205029)
文摘The humidity effects on the benzene decomposition process were investigated by the dielectric barrier discharge(DBD) plasma reactor.The results showed that the water vapor played an important role in the benzene oxidation process.It was found that there was an optimum humidity value for the benzene removal efficiency,and at around 60% relative humidity(RH),the optimum benzene removal efficiency was achieved.At a SIE of 378 J/L,the removal efficiency was 66% at 0% RH,while the removal efficiency reached 75.3% at 60% RH and dropped to 69% at 80% RH.Furthermore,the addition of water inhibited the formation of ozone and NO2 remarkably.Both of the concentrations of ozone and NO2 decreased with increasing of the RH at the same specific input energy.At a SIE of 256 J/L,the concentrations of ozone and NO2 were 5.4 mg/L and 1791 ppm under dry conditions,whereas they were only 3.4 mg/L and 1119 ppm at 63.5%RH,respectively.Finally,the outlet gas after benzene degradation was qualitatively analyzed by FT-IR and GC-MS to determine possible intermediate byproducts.The results suggested that the byproducts in decomposition of benzene primarily consisted of phenol and substitutions of phenol.Based on these byproducts a benzene degradation mechanism was proposed.
基金supported by the National Nature Science Foundation of China(21273205)the Innovation Found for Technology Based Firms of China(10C26214104505)+1 种基金the Chinese Post-doctorate Science Fund 51th batch of surface subsidizes(2012M511125)the Scientific Research Foundation of Graduate School of Zhengzhou University
文摘Ru-Ce catalysts were prepared by a co-precipitation method.The effects of Ce precursors with different valences and Ce contents on the catalytic performance of Ru-Ce catalysts were investigated in the presence of ZnSO4.The Ce species in the catalysts prepared with different valences of the Ce precursors all exist as CeO2 on the Ru surface.The promoter CeO2alone could not improve the selectivity to cyclohexene of Ru catalysts.However,almost all the CeO2 in the catalysts could react with the reaction modifier ZnSO4 to form(Zn(OH)2)3(ZnSO4)(H2O)3 salt.The amount of the chemisorbed salt increased with the CeO2 loading,resulting in the decrease of the activity and the increase of the selectivity to cyclohexene of Ru catalyst.The Ru-Ce catalyst with the optimum Ce/Ru molar ratio of 0.19 gave a maximum cyclohexene yield of 57.4%.Moreover,this catalyst had good stability and excellent reusability.
基金supported by the National Nature Science Foundation of China (21073184 and 21103175)One Hundred Person Project of the Chinese Academy of Sciences
文摘Preparation of dispersed transition metal oxides catalyst with low oxidation state still remains a challenging task in heterogeneous catalysis.In this study,vanadium oxides supported on zeolite SBA-15 have been prepared under hydrothermal condition using V 2 O 5 and oxalic acid as sources of vanadium and reductant,respectively.The structures of samples,especially the oxidation state of vanadium,and the surface distribution of vanadium oxide species,have been thoroughly characterized using various techniques,including N 2-physisorption,X-ray diffraction(XRD),transmission electron microscopy(TEM),X-ray photoelectron spectroscopy(XPS),UV-visible spectra(UV-Vis) and UV-visible-near infrared spectra(UV-Vis-NIR).It is found that the majority of supported vanadium was in the form of vanadium(IV) oxide species with the low valence of vanadium.By adjusting hydrothermal treatment time,the surface distribution of vanadium(IV) oxide species can be tuned from vanadium(IV) oxide cluster to crystallites.These materials have been tested in the hydroxylation of benzene to phenol in liquid-phase with molecular oxygen in the absence of reductant.The catalyst exhibits high selectivity for phenol(61%) at benzene conversion of 4.6%,which is a relatively good result in comparison with other studies employing molecular oxygen as the oxidant.
文摘The title compound C6H4(C7H5N2)2 was prepared by the condensation of o-phenyl- enediamine with o-phthalic acid and characterized by elemental analysis, IR, UV and H NMR 1 spectra, and its structure was determined by single-crystal X-ray diffraction. The crystal belongs to orthorhombic system, space group Pbcn with a = 17.928(8), b = 8.828(4), c = 9.752(4)?, Z = 4, V = 1543.4(12) ?3, Dc = 1.336 g/cm3, Mr = 310.35, λ(MoKα) = 0.71073 ?, μ = 0.082 mm-1, F(000) = 648, R = 0.0405 and wR = 0.1092. A total of 1693 unique reflections were collected, of which 1319 with I > 2σ(I) were observed. It is shown that the compound molecule belongs to C2 point group. A one-dimensional chain structure was formed by the intermolecular hydrogen bonds (N(2)–H… N(1)).
基金supported by the Program for National Natural Science Foundation of China (No.51177007)Liaoning Excellent Talents in University of China (Project No.2009R09)863 Program of China (No.2009AA064101-4)
文摘In this work, a novel gas phase silent-packed bed hybrid discharge plasma reactor has been proposed, and its ability to control a simulative gas stream containing 240 ppm benzene is experimentally investigated. In order to optimize the geometry of the reactor, the benzene conversion rate and energy yield (EY) were compared for various inner electrode diameters and quartz tube shapes and sizes. In addition, benzene removal efficiency in different discharge regions was qualitatively analyzed and the gas parameter (space velocity) was systematically studied. It has been found that silent-packed bed hybrid discharge plasma reactor can effectively decompose benzene. Benzene removal proved to achieve an optimum value of 60% with a characteristic energy density of 255 J/L in this paper with a 6 mm bolt high-voltage electrode and a 13 mm quartz tube. The optimal space velocity was 188.1 h^-1, which resulted in moderate energy yield and removal efficiency. Reaction by-products such as hydroquinone, heptanoic acid, 4-nitrocatechol, phenol and 4-phenoxy-phenol were identified by mean of GC-MS. In addition, based on these organic by-products, a benzene destruction pathway was proposed.
基金supported by the National Natural Science Foundation of China(20977046, 20737001) the Natural Science Foundation of Zhejiang Province(2007Y507280)
文摘In this paper we take photobacterium phosphoreum (T3) as the experimental bacteria, and determine the half-inhibitory concentration (-1gEC50) against the photobacterium phosphoreum of 16 halogenated benzenes. Using B3LYP method of DFT in the Gaussian 03 program, we obtain the structural and thermodynamic descriptors of 16 halogenated benzenes by fully-optimized calculation at the 6-311G** level. Taking the structural and thermodynamic descriptors as theoretical descriptors, the 2D QSAR model (R2 = 0.983) was established, which can be utilized to predict -lgEC50 of halogenated benzene according to the corrected linear solvation energy theory based on the experimental data of-lgECs0. In addition, the relationship between the toxicity and 3D spatial structure of the compound is studied by comparing the molecular similarity index analysis (CoMSIA) of 3D-QSAR method. By cross validation, the correlation coefficient q2 of CoMSIA model is 0.687, and the conventional correlation coefficient R2 = 0.958. The model is stable and reliable with great predictive ability. The 3D-QSAR model shows that the toxicity of halogenated benzene compound is mainly affected by the characteristics of hydrophobie field of the substituted halogens.
基金financial support from the National Natural Science Foundation of China (No.2177061270)
文摘The ZSM-22 and ZSM-35 zeolites were synthesized via the hydrothermal crystallization method. The samples were characterized by XRD, SEM, N_2 adsorption-desorption, NH_3-TPD, TPO, TG, and Raman spectrometry, and the results showed that ZSM-22 and ZSM-35 possessed similar microporous volume and acidity. In the alkylation of benzene with methanol, ZSM-22 and ZSM-35 showed different coke location, coking rate and graphitizing degree. Compared with the industrial ZSM-5, ZSM-22 and ZSM-35 both showed higher selectivity of toluene and xylene(93.63% and 96.50%,respectively) during the alkylation of benzene with methanol, and the selectivity of para-xylene in xylene isomers was51.96% and 41.45%, respectively. Meanwhile, the selectivity of ethylbenzene and C_9^+ aromatics was also lower than that of industrial ZSM-5.
基金Project supported by the National Basic Research Program(973)of China(No.2006CB403400).
文摘A series of batch experiments were performed using mixed bacterial consortia to investigate biodegradation performance of benzene, toluene, ethylbenzene and three xylene isomers (BTEX) under nitrate, sulfate and ferric iron reducing conditions. The results showed that toluene, ethylbenzene, m-xylene and o-xylene could be degraded independently by the mixed cultures coupled to nitrate, sulfate and ferric iron reduction. Under ferric iron reducing conditions the biodegradation of benzene and p-xylene could be occurred only in the presence of other alkylbenzenes. Alkylbenzenes can serve as the primary subs'rates to stimulate the transformation of benzene and p-xylene under anaerobic conditions. Benzene and p-xylene are more toxic than toluene and ethylbenzene, under the three terminal electron acceptors conditions, the degradation rates decreased with toluene 〉 ethylbenzene 〉 m-xylene 〉 o-xylene〉 benzene 〉 p- xylene. Nitrate was a more favorable electron acceptor compared to sulfate and ferric iron. The ratio between sulfate consumed and the loss of benzene, toluene, ethylbenzene, o-xylene, m-xylene, p-xylene was 4.44, 4.51, 4.42, 4.32, 4.37 and 4.23, respectively; the ratio between nitrate consumed and the loss of these substrates was 7.53, 6.24, 6.49, 7.28, 7.81, 7.61, respectively; the ratio between the consumption of ferric iron and the loss of toluene, ethylbenzene, o-xylene, m-xylene was 17.99, 18.04, 18.07, 17.97, respectively.