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
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
The degradation mechanism of photocrosslinking products formed by cyclized polyisoprene-diazide system under the influence of the different alkyl benzene sulfonic acids was studied. The effects of alkyl chain length a...The degradation mechanism of photocrosslinking products formed by cyclized polyisoprene-diazide system under the influence of the different alkyl benzene sulfonic acids was studied. The effects of alkyl chain length and the concentration of alkyl benzene sulfonic acids on the rate of degradation reaction were discussed. It was found that in the initial stage of degradation, the cyclicity ratio and the average fused ring number did not change considerably, but the percentage of uncyclized parts content varied significantly. The suitable mechanism was supposed.展开更多
The retention behaviors of benzene and its alkyl homologues in microemulsion electrokinetic chromatography were investigated in both anionic and cationic surfactant MEEKC systems. The effects of the composition of mic...The retention behaviors of benzene and its alkyl homologues in microemulsion electrokinetic chromatography were investigated in both anionic and cationic surfactant MEEKC systems. The effects of the composition of microemulsion on retention time and selectivity were studied. A good linear relationship was obtained between log k and the carbon number of alkyl chain.展开更多
A series of ZnO-ZrO_(2) solid solutions with different Zn contents were synthesized by the urea coprecipitation method,which were coupled with H-ZSM-5 zeolite to form bifunctional catalysts.As a new benzene alkylation...A series of ZnO-ZrO_(2) solid solutions with different Zn contents were synthesized by the urea coprecipitation method,which were coupled with H-ZSM-5 zeolite to form bifunctional catalysts.As a new benzene alkylation reagent,syngas was used instead of methanol to realize the efficient conversion of syngas and benzene into toluene and xylene.A suitable ratio of ZnO-ZrO_(2) led to the significant improvement in the catalytic performance,and a suitable amount of acid helped to increase the selectivity of toluene/xylene and reduce the selectivity of the by-products ethylbenzene and C^(9+) aromatics.The highest benzene conversion of 89.2%and toluene/xylene selectivity of 88.7%were achieved over 10%ZnO-ZrO_(2)&H-ZSM-5(Si/Al=23)at a pressure of 3 MPa and a temperature of 450℃.In addition,the effect of the zeolite framework structure on product distribution was examined.Similar to the molecular dynamics of aromatic hydrocarbons,H-ZSM-5 zeolites comprise 10-membered-ring pores,which are beneficial to the activation of benzene;hence,the conversion of benzene is higher.H-ZSM-35 and HMOR zeolites exhibited small eight-membered-ring channels,which were not conducive to the passage of benzene;hence,the by-product ethylbenzene exhibits a higher selectivity.The distance between the active centers of the bifunctional catalysts was the main factor affecting the catalytic performance,and the powder mixing method was more conducive to the conversion of syngas and benzene.展开更多
Alkylation of benzene with carbon dioxide and hydrogen to produce toluene and xylene could increase the added-value of surplus benzene as well as relieve environmental problems like green-house effect.In this work,the...Alkylation of benzene with carbon dioxide and hydrogen to produce toluene and xylene could increase the added-value of surplus benzene as well as relieve environmental problems like green-house effect.In this work,the alkylation benzene with carbon dioxide and hydrogen reaction was proceeded by using the mixture of zinc-zirconium oxide and HZSM-5 as bifunctional catalyst.The equivalent of Zn/Zr=1 displays the best catalytic performance at 425℃ and 3.0 MPa,and benzene conversion reaches 42.9%with a selectivity of 90%towards toluene and xylene.Moreover,the carbon dioxide conversion achieves 23.3%and the carbon monoxide selectivity is lower than 35%,indicating that more than 50%carbon dioxide has been effectively incorporated into the target product,which is the best result as far as we know.Combined with characterizations,it indicated that the Zn and Zr formed a solid solution under specific conditions(Zn/Zr=1).The as-formed solid solution not only possesses a high surface area but also provides a large amount of oxygen vacancies.Additionally,the bifunctional catalyst has excellent stabilities that could keep operating without deactivation for at least 80 h.This work provides promising industrial applications for the upgrading of aromatics.展开更多
Benzene alkylation catalyzed by immobilized ionic liquids(ILs)on solid carriers is considered as a heterogeneous reaction,in which the interfacial properties play an important role.Hence,the interfacial characteristic...Benzene alkylation catalyzed by immobilized ionic liquids(ILs)on solid carriers is considered as a heterogeneous reaction,in which the interfacial properties play an important role.Hence,the interfacial characteristics between benzene/1-dodecene mixture and immobilized chloroaluminate ILs with different alkyl chain length on the silica substrate were investigated by molecular dynamics simulation.The grafted ILs can obviously promote the enrichment of benzene near the interface,leading to a higher ratio of benzene to dodecene,and the interfacial width increases slightly with increased alkyl chain of grafted cations.At the same time,the grafted cations can also enhance the benzene diffusion and suppress the dodecene diffusion at the interface,which probably helps to inhibit the inactivation of catalysts.This work provides deeply insights into the rational design of novel immo-bilized ILs catalysts for the benzene alkylation.展开更多
Nitrided hierarchical porous ZSM-5 was synthesized by nitridation of hierarchical porous ZSM-5 with flowing ammonia at elevated temperature.The samples were characterized by XRD,SEM,Nitrogen sorption isotherms,NH3-TPD...Nitrided hierarchical porous ZSM-5 was synthesized by nitridation of hierarchical porous ZSM-5 with flowing ammonia at elevated temperature.The samples were characterized by XRD,SEM,Nitrogen sorption isotherms,NH3-TPD and Py-IR,and evaluated in alkylation of benzene and methanol.The result indicated that the high specific surface area of parent ZSM-5 was maintained,while the Bronsted acidity was effectively adjusted by nitridation.Moreover,the high suppression of ethylbenzene was observed on nitrided catalyst and this could be attributed to the decrease of Bronsted acidity which suppressed the methanol to olefins reactions.展开更多
Linear alkyl benzene (LAB) will be used as the solvent in a liquid scintillator mixture for the JUNO antineutrino experiment. Its light absorption properties should therefore be understood prior to its effective use...Linear alkyl benzene (LAB) will be used as the solvent in a liquid scintillator mixture for the JUNO antineutrino experiment. Its light absorption properties should therefore be understood prior to its effective use in the experiment. Attenuation length measurements at a light wavelength of 430 nm have been performed on samples of LAB prepared for the JUNO experiment. Inorganic impurities in LAB have also been studied for their possibilities of light absorption in our wavelength of interest. In view of a tentative plan by the JUNO collaboration to utilize neutron capture with hydrogen in the detector, we also present in this work a preliminary study on the carbon-hydrogen ratio and the attenuation length of the samples.展开更多
Linear Alkyl Benzene (LAB) is a promising liquid scintillator solvent in neutrino experiments because it has many appealing properties. The timing properties of LAB-based liquid scintillator have been studied throug...Linear Alkyl Benzene (LAB) is a promising liquid scintillator solvent in neutrino experiments because it has many appealing properties. The timing properties of LAB-based liquid scintillator have been studied through ultraviolet and ionization excitation in this study. The decay time of LAB, PPO and bis-MSB is found to be 48.6 ns, 1.55 ns and 1.5 ns, respectively. A model can describe the absorption and re-emission process between PPO and bis-MSB perfectly. The energy transfer time between LAB and PPO with different concentrations can be obtained via another model. We also show that the LAB-based liquid scintillator has good (n, γ) and (α, γ) discrimination power.展开更多
The source rocks and crude oils from the Qianjiang Formation (Eocene) in the Jiangban basin have been systematically studied in the present work. Supergene hydrocarboholds are characterized by (ⅰ) high alteration rat...The source rocks and crude oils from the Qianjiang Formation (Eocene) in the Jiangban basin have been systematically studied in the present work. Supergene hydrocarboholds are characterized by (ⅰ) high alteration ratio of soluble organic matter over organic carbon and middle ratio of hydrocarbon over organic carbon; (ⅱ) high content of non-hydrocarbon plus asphahene in extracts or crude oils; (ⅲ) sulfur-rich crude oils being an important immature crude oil; (ⅳ) alkane showing high content of phytane, gammacerane and marked even-carbon predominance or odd-carbon predominance; (ⅴ) aromatic biomarkers being distinctly classified into four groups; (ⅵ) pronounced evencarbon predominance in alkyl henzenes. In combination of all geochemical data. it is extrapolated that exploration of immature crude oil in hypersaline environment should be noticed.展开更多
We studied the temperature dependence of the light yield of linear alkyl benzene (LAB)-based and mesitylene-based liquid scintillators. The light yield increases by 23% for both liquid scintillators when the temper-...We studied the temperature dependence of the light yield of linear alkyl benzene (LAB)-based and mesitylene-based liquid scintillators. The light yield increases by 23% for both liquid scintillators when the temper- ature is lowered from 26 ℃ to -40 ℃, correcting for the temperature response of the photomultiplier tube. The measurements help to understand the energy response of liquid scintillator detectors. Especially, the next generation reactor neutrino experiments for neutrino mass hierarchy, such as the Jiangmen Underground Neutrino Observatory (JUNO), require very high energy resolution. As no apparent degradation on the liquid scintillator transparency was observed, lowering the operation temperature of the detector to ~4 ℃ will increase the photoelectron yield of the detector by 13%, combining the light yield increase of the liquid scintillator and the quantum efficiency increase of the photomultiplier tubes.展开更多
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 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.
文摘The degradation mechanism of photocrosslinking products formed by cyclized polyisoprene-diazide system under the influence of the different alkyl benzene sulfonic acids was studied. The effects of alkyl chain length and the concentration of alkyl benzene sulfonic acids on the rate of degradation reaction were discussed. It was found that in the initial stage of degradation, the cyclicity ratio and the average fused ring number did not change considerably, but the percentage of uncyclized parts content varied significantly. The suitable mechanism was supposed.
文摘The retention behaviors of benzene and its alkyl homologues in microemulsion electrokinetic chromatography were investigated in both anionic and cationic surfactant MEEKC systems. The effects of the composition of microemulsion on retention time and selectivity were studied. A good linear relationship was obtained between log k and the carbon number of alkyl chain.
基金financial support from the National Key Research&Development Program of China(2018YFB0604901)the National Natural Science Foundation of China(21706210)the Key Research&Development Program of Shaanxi Province(2020ZDLGY11-06)。
文摘A series of ZnO-ZrO_(2) solid solutions with different Zn contents were synthesized by the urea coprecipitation method,which were coupled with H-ZSM-5 zeolite to form bifunctional catalysts.As a new benzene alkylation reagent,syngas was used instead of methanol to realize the efficient conversion of syngas and benzene into toluene and xylene.A suitable ratio of ZnO-ZrO_(2) led to the significant improvement in the catalytic performance,and a suitable amount of acid helped to increase the selectivity of toluene/xylene and reduce the selectivity of the by-products ethylbenzene and C^(9+) aromatics.The highest benzene conversion of 89.2%and toluene/xylene selectivity of 88.7%were achieved over 10%ZnO-ZrO_(2)&H-ZSM-5(Si/Al=23)at a pressure of 3 MPa and a temperature of 450℃.In addition,the effect of the zeolite framework structure on product distribution was examined.Similar to the molecular dynamics of aromatic hydrocarbons,H-ZSM-5 zeolites comprise 10-membered-ring pores,which are beneficial to the activation of benzene;hence,the conversion of benzene is higher.H-ZSM-35 and HMOR zeolites exhibited small eight-membered-ring channels,which were not conducive to the passage of benzene;hence,the by-product ethylbenzene exhibits a higher selectivity.The distance between the active centers of the bifunctional catalysts was the main factor affecting the catalytic performance,and the powder mixing method was more conducive to the conversion of syngas and benzene.
基金sponsored financially by the National Natural Science Foundation of China (Grant No.21776076)the Fundamental Research Funds for the Central Universities (Grant No.JKA01211710).
文摘Alkylation of benzene with carbon dioxide and hydrogen to produce toluene and xylene could increase the added-value of surplus benzene as well as relieve environmental problems like green-house effect.In this work,the alkylation benzene with carbon dioxide and hydrogen reaction was proceeded by using the mixture of zinc-zirconium oxide and HZSM-5 as bifunctional catalyst.The equivalent of Zn/Zr=1 displays the best catalytic performance at 425℃ and 3.0 MPa,and benzene conversion reaches 42.9%with a selectivity of 90%towards toluene and xylene.Moreover,the carbon dioxide conversion achieves 23.3%and the carbon monoxide selectivity is lower than 35%,indicating that more than 50%carbon dioxide has been effectively incorporated into the target product,which is the best result as far as we know.Combined with characterizations,it indicated that the Zn and Zr formed a solid solution under specific conditions(Zn/Zr=1).The as-formed solid solution not only possesses a high surface area but also provides a large amount of oxygen vacancies.Additionally,the bifunctional catalyst has excellent stabilities that could keep operating without deactivation for at least 80 h.This work provides promising industrial applications for the upgrading of aromatics.
基金The financial support by State Key Laboratory of Heavy Oil Processing
文摘Benzene alkylation catalyzed by immobilized ionic liquids(ILs)on solid carriers is considered as a heterogeneous reaction,in which the interfacial properties play an important role.Hence,the interfacial characteristics between benzene/1-dodecene mixture and immobilized chloroaluminate ILs with different alkyl chain length on the silica substrate were investigated by molecular dynamics simulation.The grafted ILs can obviously promote the enrichment of benzene near the interface,leading to a higher ratio of benzene to dodecene,and the interfacial width increases slightly with increased alkyl chain of grafted cations.At the same time,the grafted cations can also enhance the benzene diffusion and suppress the dodecene diffusion at the interface,which probably helps to inhibit the inactivation of catalysts.This work provides deeply insights into the rational design of novel immo-bilized ILs catalysts for the benzene alkylation.
基金the National Natural Science Foundation of China (Nos. 21476207 and 21506189)Zhejiang Postdoctoral Research Funded Projects (No. BSH1502147)National Basic Research Program of China (973 Program, No. 2011CB710800)
文摘Nitrided hierarchical porous ZSM-5 was synthesized by nitridation of hierarchical porous ZSM-5 with flowing ammonia at elevated temperature.The samples were characterized by XRD,SEM,Nitrogen sorption isotherms,NH3-TPD and Py-IR,and evaluated in alkylation of benzene and methanol.The result indicated that the high specific surface area of parent ZSM-5 was maintained,while the Bronsted acidity was effectively adjusted by nitridation.Moreover,the high suppression of ethylbenzene was observed on nitrided catalyst and this could be attributed to the decrease of Bronsted acidity which suppressed the methanol to olefins reactions.
基金Supported by China Ministry of Science and Technology(2013CB834300)
文摘Linear alkyl benzene (LAB) will be used as the solvent in a liquid scintillator mixture for the JUNO antineutrino experiment. Its light absorption properties should therefore be understood prior to its effective use in the experiment. Attenuation length measurements at a light wavelength of 430 nm have been performed on samples of LAB prepared for the JUNO experiment. Inorganic impurities in LAB have also been studied for their possibilities of light absorption in our wavelength of interest. In view of a tentative plan by the JUNO collaboration to utilize neutron capture with hydrogen in the detector, we also present in this work a preliminary study on the carbon-hydrogen ratio and the attenuation length of the samples.
基金Supported by National Natural Science Foundation of China (10890094, 11011120080)
文摘Linear Alkyl Benzene (LAB) is a promising liquid scintillator solvent in neutrino experiments because it has many appealing properties. The timing properties of LAB-based liquid scintillator have been studied through ultraviolet and ionization excitation in this study. The decay time of LAB, PPO and bis-MSB is found to be 48.6 ns, 1.55 ns and 1.5 ns, respectively. A model can describe the absorption and re-emission process between PPO and bis-MSB perfectly. The energy transfer time between LAB and PPO with different concentrations can be obtained via another model. We also show that the LAB-based liquid scintillator has good (n, γ) and (α, γ) discrimination power.
文摘The source rocks and crude oils from the Qianjiang Formation (Eocene) in the Jiangban basin have been systematically studied in the present work. Supergene hydrocarboholds are characterized by (ⅰ) high alteration ratio of soluble organic matter over organic carbon and middle ratio of hydrocarbon over organic carbon; (ⅱ) high content of non-hydrocarbon plus asphahene in extracts or crude oils; (ⅲ) sulfur-rich crude oils being an important immature crude oil; (ⅳ) alkane showing high content of phytane, gammacerane and marked even-carbon predominance or odd-carbon predominance; (ⅴ) aromatic biomarkers being distinctly classified into four groups; (ⅵ) pronounced evencarbon predominance in alkyl henzenes. In combination of all geochemical data. it is extrapolated that exploration of immature crude oil in hypersaline environment should be noticed.
基金Supported by National Science Foundation of China(11205183,11005117,11225525,11390384)
文摘We studied the temperature dependence of the light yield of linear alkyl benzene (LAB)-based and mesitylene-based liquid scintillators. The light yield increases by 23% for both liquid scintillators when the temper- ature is lowered from 26 ℃ to -40 ℃, correcting for the temperature response of the photomultiplier tube. The measurements help to understand the energy response of liquid scintillator detectors. Especially, the next generation reactor neutrino experiments for neutrino mass hierarchy, such as the Jiangmen Underground Neutrino Observatory (JUNO), require very high energy resolution. As no apparent degradation on the liquid scintillator transparency was observed, lowering the operation temperature of the detector to ~4 ℃ will increase the photoelectron yield of the detector by 13%, combining the light yield increase of the liquid scintillator and the quantum efficiency increase of the photomultiplier tubes.