A comprehensive understanding of the structure and dynamic evolution of catalytic active sites is vital for advancing the study of liquid-phase acetylene hydrochlorination.Here,we successfully developed a Ru-DIPEA/TMS...A comprehensive understanding of the structure and dynamic evolution of catalytic active sites is vital for advancing the study of liquid-phase acetylene hydrochlorination.Here,we successfully developed a Ru-DIPEA/TMS catalyst optimised through systematic composition and condition tuning,demonstrating exceptional performance with 95.5%C_(2)H_(2)conversion and sustaining over 91.1%activity along with nearly 100%selectivity for VCM during a continuous 900-h test.Using a combination of characterisation techniques,including UV–vis spectroscopy,FT-IR spectroscopy,X-ray photoelectron spectroscopy,singlecrystal X-ray diffraction,and X-ray absorption spectroscopy,along with density functional theory(DFT)calculations,the structure and dynamic behaviour of the active sites were thoroughly investigated under the synergistic influence of ligands and HCl.The results revealed that HCl activation induces a significant structural transformation of the active sites,leading to the formation of a hexacoordinate complex,Ru(CO)_(2)C_(12)(C_(6)H_(15)N·HCl)_(2).DFT calculations further elucidated the mechanism underlying active site formation,revealing that an increased electron density around the Ru centre and corresponding changes in its coordination environment play critical roles in enhancing catalyst stability and activity.This study contributes to a deeper understanding of the structural basis of active site evolution during acetylene hydrochlorination,offering both practical insights into industrial applications and foundational knowledge for advancing liquid-phase catalysis.展开更多
Pt nanoparticles entrapped in ordered mesoporous CMK-3 carbons with p6mm symmetry were prepared using a facile impregnation method, and the resulting materials were characterized using X-ray diffraction spectroscopy, ...Pt nanoparticles entrapped in ordered mesoporous CMK-3 carbons with p6mm symmetry were prepared using a facile impregnation method, and the resulting materials were characterized using X-ray diffraction spectroscopy, N2 adsorption-desorption, scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. The Pt nanoparticles were highly dispersed in the CMK-3 with 43.7% dispersion. The Pt/CMK-3 catalyst was an effective catalyst for the liquid-phase hydrogenation of nitrobenzene and its derivatives under the experimental conditions studied here. The Pt/CMK-3 catalyst was more active than commercial Pt/C catalyst in most cases. A highest turnover frequency of 43.8 s-1 was measured when the Pt/CMK-3 catalyst was applied for the hydrogenation of 2-methyl-nitrobenzene in ethanol under optimal conditions. It is worthy of note that the Pt/CMK-3 catalyst could be recycled easily, and could be reused at least fourteen times without any loss in activity or selectivity for the hydrogenation of nitrobenzene in ethanol.展开更多
Liquid phase oxidation of toluene is an environmental benign route for the production of benzoic acid.In a φ48mm bubble column reactor,the commercial process of toluene liquid phase oxidation was conducted with Co(CH...Liquid phase oxidation of toluene is an environmental benign route for the production of benzoic acid.In a φ48mm bubble column reactor,the commercial process of toluene liquid phase oxidation was conducted with Co(CH3COO)2.4H2O as catalyst.The Co2+ concentration [Co2+] was determined by extraction spectrophotometry and hereby the Co3+ concentration [Co3+] was obtained by mass balance.The results showed that [Co3+] reached the maximum at about 25-30min.[Co3+] increased with increasing Co catalyst amount at total Co concentration<150 mg.L-1 of toluene.The conversion of toluene,yield and selectivity of benzoic acid increased with the increasing [Co3+/Co2+] max.A high [Co3+] and a high [Co3+]/[Co2+] ratio are beneficial to the reaction.展开更多
The homogeneous liquid was separated into two phases, （Fe, Co）-rich LI and Cu-rich L2, once the melt was undercooled below a liquid-phase separation temperature Tsep. If the duration from Tsep to Tsl （solidificatio...The homogeneous liquid was separated into two phases, （Fe, Co）-rich LI and Cu-rich L2, once the melt was undercooled below a liquid-phase separation temperature Tsep. If the duration from Tsep to Tsl （solidification temperature of LI phase）, termed the liquid-phase separation interval Δt, exceeded a critical value, an eggtype structure was observed. By utilizing differential thermal analyses （DTA）, the solidification process of the undercooled Fe-Co-Cu alloys was studied. Additionally, an immiscible boundary was obtained, which was a convex parabola with a symmetrical axis of XCu=0.52. Depending on the relative amounts of LI and L2, the minor phase was nucleated firstly to form liquid droplets and separated from the original liquids at the beginning of liquid-phase separation.展开更多
The volatile and semi-volatile components in tobacco flavor additives were extracted by both simultaneous distillation extraction and solid-phase micro-extraction. Extraction conditions for solid-phase micro-extractio...The volatile and semi-volatile components in tobacco flavor additives were extracted by both simultaneous distillation extraction and solid-phase micro-extraction. Extraction conditions for solid-phase micro-extraction were optimized with information theory. Then, detection were accomplished by gas chromatography-mass spectrometry. Characteristic of each method was compared. Qualitative analysis and quantitative analysis of 6# tobacco flavor sample were accomplished through both simultaneous distillation extraction and solid-phase micro-extraction. The experimental results show that solid-phase micro-extraction method is the first choice for qualitative analysis and simultaneous distillation extraction is another good selection for quantitative analysis. By means of simultaneous distillation extraction, 20 components are identified, accounting for 92.77% of the total peak areas. Through solid-phase micro-extraction, there are 17 components identified accounting for 91.49% of the total peak areas. The main aromatic components in 6# tobacco flavor sample are propanoic acid, 2-hydroxy-, ethyl ester, menthol and menthyl acetate. The presented method has been successfully used for quality control of tobacco flavor.展开更多
The liquid-phase furfural （FAL） hydrogenation to furfuryl alcohol （FOL） and tetrahydrofurfuryl alcohol （THFOL） was investigated using sulfonate group （-SO3H） grafted activated carbon （AC） supported Ni cataly...The liquid-phase furfural （FAL） hydrogenation to furfuryl alcohol （FOL） and tetrahydrofurfuryl alcohol （THFOL） was investigated using sulfonate group （-SO3H） grafted activated carbon （AC） supported Ni catalyst, which was prepared and activated simultaneously by liquid phase reduction method. This functionalized nickel catalyst demonstrated an enhanced catalytic performance for selective hydrogenation of FAL, in which almost 100% FOL （〈80℃） and THFOL （〉100℃） selectivity with complete conversion was obtained, respectively. More importantly, the conversion of transfer hydrogenation of FAL to FOL also can reach almost 100% under optimal conditions （140℃, 4.0h）. The effect of -SO3H was evaluated and systematically analyzed by the combination of reaction performance and physico-chemical characterizations. Cycling test proved the prepared catalyst could be recycled and reused for several times without noticeably reducing catalytic activity of hvdrogenation.展开更多
The kinetics of liquid-phase hydrogenation of toluene catalyzed by MlNi_5 was studied by investigating the influences of the reaction temperature and pressure on the mass transfer-reaction processes inside the slurry....The kinetics of liquid-phase hydrogenation of toluene catalyzed by MlNi_5 was studied by investigating the influences of the reaction temperature and pressure on the mass transfer-reaction processes inside the slurry. The results show that the reaction rate accelerates when the reaction temperature increases, and reaches its maximum at about 490 K, but if temperature is higher than 510 K, the reaction rate decreases rapidly. The whole reaction process is controlled by the reaction at the surface of the catalyst particles. The mass transfer resistance at gas-liquid interface and that from the bulk liquid phase to the surface of the catalyst particle can be neglected. The apparent reaction rate is zero order for toluene concentration and first order for hydrogen concentration in the liquid phase. The kinetic model is obtained. The kinetic model fits the experimental data very well. The apparent activation energy of the hydrogen absorption reaction of MlNi_5-toluene slurry system is 41.01 kJ·mol^(-1).展开更多
The main problems with the liquid-phase technology of carbon fiber/aluminum matrix composites include poor wetting of the fiber with liquid aluminum and formation of aluminum carbide on the fibers’surface.This paper ...The main problems with the liquid-phase technology of carbon fiber/aluminum matrix composites include poor wetting of the fiber with liquid aluminum and formation of aluminum carbide on the fibers’surface.This paper aims to solve these problems.The theoretical and experimental dependence of porosity on the applied pressure were determined.The possibility of obtaining a carbon fiber/aluminum matrix composite wire with a strength value of about 1500 MPa was shown.The correlation among the strength of the carbon fiber reinforced aluminum matrix composite,the fracture surface,and the degradation of the carbon fiber surface was discussed.展开更多
Cu-Zn-Al slurry catalysts were prepared using a complete liquid-phase preparation technology under different heat treatment atmospheres.The catalysts were characterized using X-ray diffraction,X-ray photoelectron spec...Cu-Zn-Al slurry catalysts were prepared using a complete liquid-phase preparation technology under different heat treatment atmospheres.The catalysts were characterized using X-ray diffraction,X-ray photoelectron spectroscope,and N2 adsorption-desorption.Their application in the single-step synthesis of dimethyl ether from syngas was also investigated.The results indicate that the type of heat treatment atmosphere has an influence on the Cu species and the Cu0/Cu＋ ratio on the catalyst surface.Moreover,the final Cu/Zn ratio on the catalyst surface is mainly dependent on the composition and reaction environment of the catalyst and less on the type of heat treatment atmosphere.The prepared catalysts can suppress sintering of active sites at high temperatures,and the type of heat treatment atmosphere mainly affects the capability of the catalyst for methanol synthesis.The catalysts perform best using N2 as the heat treatment atmosphere.展开更多
TiO2 nanowire arrays were successfully fabricated by liquid-phase deposition method using porous alumina templates. The obtained TiO2 nanowires were characterized using Raman spectroscopy, X-ray diffraction （XRD）, s...TiO2 nanowire arrays were successfully fabricated by liquid-phase deposition method using porous alumina templates. The obtained TiO2 nanowires were characterized using Raman spectroscopy, X-ray diffraction （XRD）, scanning electron microscopy （SEM）, field emission scanning electron microscopy （FE- SEM）, transmission electron microscopy （TEM）, and selected area electron diffraction （SAED） analysis. Results of electron microscopic observations indicated that the nanowires were smooth and uniform with a diameter of about 50-80 nm and several micrometers in length. SAED, Raman, and XRD mea- surements showed that TiO2 nanowires were single-crystalline with a pure rutile structure after heating at 800 ~C for 10 h. In this situation, the nanowire constituents grew preferentially along the 〈001〉 direction. Furthermore, the formation process and mechanistic study of the Ti02 nanowire arrays were proposed and discussed in detail. The nanowires are clearly produced by the deposition of TiO2 particles on the inner wall of the template nanochannels.展开更多
According to the characteristics of FCC diesel, a technology of liquid-phase hydrodesulfurization of the diesel in tubular reactors was proposed and lab-scale experiments were carried out. A kinetic model for the hydr...According to the characteristics of FCC diesel, a technology of liquid-phase hydrodesulfurization of the diesel in tubular reactors was proposed and lab-scale experiments were carried out. A kinetic model for the hydrodesulfurization process was developed and verified. The model was utilized to predict the sulfur content of products under different operating conditions. The effects of temperature, space velocity, pressure, and hydrogen concentration on the dcsulfurization rate were investigated.展开更多
Olivine LiFePO4/C nanowires have been successfully synthesized by a simple and eco-friendly solution preparation.The phase,structure,morphology and composition of the as-prepared products were characterized by powder ...Olivine LiFePO4/C nanowires have been successfully synthesized by a simple and eco-friendly solution preparation.The phase,structure,morphology and composition of the as-prepared products were characterized by powder X-ray diffraction(XRD),scanning electron microscopy(SEM),thermogravimetric and differential-thermogravimetric analysis(TG-DTA) and energy dispersive X-ray spectrometry(EDS) techniques,showing uniform nanowire shape of LiFePO4/C with a diameter of 80-150 nm and a length of several microns.The heat-treated LiFePO4/C nanowires show excellent electrochemical properties of specific discharge capacity,rate capacity and cycling stability.In particular,the LiFePO4/C nanowires heat-treated at 400 °C show preferable first discharge specific capacity of 161 mA·h/g at 0.1C rate,while the voltage platform is 3.4 V and the first discharge specific capacity is 93 mA·h/g at 20C rate.The specific capacity retention is 98% after 50 cycles at 5C rate.展开更多
Nanobubbles have attracted considerable attention in various industrial applications due to their exceptionally long lifetime and their potential as carriers at the nanoscale.The stability and physiochemical propertie...Nanobubbles have attracted considerable attention in various industrial applications due to their exceptionally long lifetime and their potential as carriers at the nanoscale.The stability and physiochemical properties of nanobubbles are highly sensitive to the presence of surfactants that can lower their surface tension or improve their electrostatic stabilization.Herein,we report real-time observations of the dynamic behaviors of nanobubbles in the presence of soluble surfactants.Using liquid-phase transmission electron microscopy(TEM)with multi-chamber graphene liquid cells,bulk nanobubbles and surface nanobubbles were observed in the same imaging condition.Our direct observations of nanobubbles indicate that stable gas transport frequently occurs without interfaces merging,while a narrow distance is maintained between the interfaces of interacting surfactant-laden nanobubbles.Our results also elucidate that the interface curvature of nanobubbles is an important factor that determines their interfacial stability.展开更多
A kind of Ni-Cr-Fe-B-Si system amorphous alloy was used as interlayer in transient liquid-phase bonding(TLP bonding)of polycrystalline superalloy K465.The bonding behavior,microstructure feature and the tensile proper...A kind of Ni-Cr-Fe-B-Si system amorphous alloy was used as interlayer in transient liquid-phase bonding(TLP bonding)of polycrystalline superalloy K465.The bonding behavior,microstructure feature and the tensile properties of the joints were investigated.There are B-rich phase and Si-rich phase formed in the center of the seam after bonding at 1210℃for 30 min.The isothermal solidification is complete after bonding at 1210℃for 4 h.The relationship of the average width of the remnant eutectic zone and bonding time at 1210℃is nonlinear.The tensile strength of the bonded joint at room temperature and 900℃is comparable to that of K465 alloy.展开更多
Quality control of ginseng currently is mainly based on ginsenoside analysis,but rarely focuses on the volatile organic components.In the current work,an untargeted metabolomics approach,by headspace solid-phase micro...Quality control of ginseng currently is mainly based on ginsenoside analysis,but rarely focuses on the volatile organic components.In the current work,an untargeted metabolomics approach,by headspace solid-phase micro-extraction gas chromatography/mass spectrometry(HS-SPME-GC/MS),was elaborated and further employed to holistically compare the compositional difference of the volatile components simultaneously from 12 Panax herbal medicines,which included P.ginseng(PG),P.quinquefolius(PQ),P.notoginseng(PN),red ginseng(PGR),P.ginseng leaf(PGL),P.quinquefolius leaf(PQL),P.notoginseng leaf(PNL),P.ginseng flower(PGF),P.quinquefolius flower(PQF),P.notoginseng flower(PNF),P.japonicus(PJ),and P.japonicus var.major(PJvm).Chromatographic separation was performed on an HP-5MS elastic quartz capillary column using helium as the carrier gas,enabling good resolution within 1 h.We were able to characterize totally 259 volatile compounds,including 82 terpenes(T),46 alcohols(Alc),29 ketones(K),25 aldehydes(Ald),21 esters(E),and the others.By analyzing 90 batches of ginseng samples based on the untargeted metabolomics workflows,236 differential ions were unveiled,and accordingly 36 differential volatile components were discovered.It is the first report that simultaneously compares the compositional difference of volatile components among 12 Panax herbal medicines,and useful information is provided for the quality control of ginseng aside from the well-known ginsenosides.展开更多
A rapid headspace single-drop micro-extraction（mix） gas chromatography mass spectrometry（SDMEGC -MS） for the analysis of the volatile compounds in Herba Asari was developed in this study.A mixed solvent of n-tride...A rapid headspace single-drop micro-extraction（mix） gas chromatography mass spectrometry（SDMEGC -MS） for the analysis of the volatile compounds in Herba Asari was developed in this study.A mixed solvent of n-tridecane and butyl acetate（1：1） was finally used for the extraction at 70 C for 15 min with sample amount of 0.750 g and 100 mesh particle size.Under the determined conditions,the pound samples of Herba Asari were directly applied for the analysis.SDME-GC-MS,SPME-GC-MS and SD-GCMS methods were compared and the results showed that SDME-GC-MS method was a simple, inexpensive and effective way to measure the volatile compounds in Herba Asari and could be used for the analysis of volatile compounds in complex samples.展开更多
The interfacial reactions in partial transient liquid-phase bonding of Si3N4 ceramics with Ti/Ni/Ti interlayers were studied by means of scanning electron microscopy （SEM）, energy dispersive spectrometry （EDS） and...The interfacial reactions in partial transient liquid-phase bonding of Si3N4 ceramics with Ti/Ni/Ti interlayers were studied by means of scanning electron microscopy （SEM）, energy dispersive spectrometry （EDS） and X-ray diffractometry （XRD）. It was shown that the interfacial structure of Si3N4/TiN/Ti5Si3+Ti5Si4 + Ni3Si/ （NiTi ） /Ni3Ti/ Ni was formed after bonding. The activation energies for TiN layer and the mixed reaction layer of Ti5Si3 + Ti5Si4 + Ni3Si are 546. 8 kJ/mol and 543. 9 kJ/mol, respectively. The formation and transition processes of interface layer sequence in the joint were clarified by diffusion path. An important characteristic, which is different from the conventional brazing and soid-state diffusion bonding, has been found, i. e., during the partial transient liquid-phase bonding, not only the reaction layers which have formed grow, but also the diffusion path in the subsequent reaction changes because of the remarkable variation of the concentration on the metal side.展开更多
The 8% （mass fraction） yttrium-partially-stabilized zirconia （8YSZ） ceramic was fabricated via liquid phase sintering at 1 200-1 400℃ by adding different mass ratios of CuO-16.7%TiO2 （molar fraction） as sinteri...The 8% （mass fraction） yttrium-partially-stabilized zirconia （8YSZ） ceramic was fabricated via liquid phase sintering at 1 200-1 400℃ by adding different mass ratios of CuO-16.7%TiO2 （molar fraction） as sintering aid. Relative density, microstructure, Vickers hardness and bending strength as a function of sintering temperature and additive content were investigated. The experiment results show that liquid phase sintering at low temperature can be realized through adding CUO-16.7% TiO2 to 8YSZ. The Vickers hardness and bending strength of samples with sintering aid are generally much higher than those of samples without sintering aid for all sintering temperatures, and increase with the increase of sintering temperature. When the addition content of CUO-16.7% TiO2 is beyond 0.5%, the relative density, Vickers hardness and bending strength decrease with the increase of the mass ratio of sintering aid. Low additions of sintering aid are beneficial to aiding densification; high additions of sintering aid are detrimental to the sintered properties mainly due to greater amounts of pores generated by the volatilization of oxygen with the eutectic reaction between copper oxide and titanium dioxide. It is found that the fine grain size and high relative density are two main reasons of the high bending strength and Vickers hardness of the materials.展开更多
An efficient poly(ethylene glycol) (PEG)-supported liquid-phase parallel approach to di(aryloxyacetyl)thiosemicarbazides is described. PEG-bound phenol reacted with chloroacetic acid to afford PEG-bound phenyloxyaceti...An efficient poly(ethylene glycol) (PEG)-supported liquid-phase parallel approach to di(aryloxyacetyl)thiosemicarbazides is described. PEG-bound phenol reacted with chloroacetic acid to afford PEG-bound phenyloxyacetic acid, which was readily converted into corresponding phenyloxyacetyl chloride. Subsequent nucleophilic substitution with ammonium thiocyanate followed by addition of aryloxyacetic acid hydrazides gave PEG-bound di(aryloxyacetyl)thiosemi-carbazides, which were easily cleaved to give the resulting library of 1-aryloxyacetyl-4-(4'-methoxylcarbonylphenyloxyacetyl)thiosemicarbazides in good to high yield and high purity.展开更多
Pt/CeO2–ZrO2–SnO2/γ-Al2O3 catalysts were prepared by co-precipitation and wet impregnation methods for catalytic oxidation of acetaldehyde to acetic acid in water. In the present catalysts, Pt and CeO2–ZrO2–SnO2 ...Pt/CeO2–ZrO2–SnO2/γ-Al2O3 catalysts were prepared by co-precipitation and wet impregnation methods for catalytic oxidation of acetaldehyde to acetic acid in water. In the present catalysts, Pt and CeO2–ZrO2–SnO2 were successfully dispersed on the γ-Al2O3 support.Dependences of platinum content and reaction time on the selective oxidation of acetaldehyde to acetic acid were investigated to optimize the reaction conditions for obtaining both high acetaldehyde conversion and highest selectivity to acetic acid. Among the catalysts, a Pt（6.4 wt.%）/Ce0.68Zr0.17Sn0.15O2.0（16 wt.%）/γ-Al2O3 catalyst showed the highest acetaldehyde oxidation activity. On this catalyst, acetaldehyde was completely oxidized after the reaction at 0°C for 8 hr, and the selectivity to acetic acid reached to 95%and higher after the reaction for 4 hr and longer.展开更多
基金supported by the National Natural Science Foundation of China(No.22378308)Jing-Jin-Ji Regional Integrated Environmental Improvement-National Science and Technology Major Project(No.2024ZD1200301–2)the Scientific and Technological Project of Yunnan Precious Metal Laboratory(No.YPML2023050202)。
文摘A comprehensive understanding of the structure and dynamic evolution of catalytic active sites is vital for advancing the study of liquid-phase acetylene hydrochlorination.Here,we successfully developed a Ru-DIPEA/TMS catalyst optimised through systematic composition and condition tuning,demonstrating exceptional performance with 95.5%C_(2)H_(2)conversion and sustaining over 91.1%activity along with nearly 100%selectivity for VCM during a continuous 900-h test.Using a combination of characterisation techniques,including UV–vis spectroscopy,FT-IR spectroscopy,X-ray photoelectron spectroscopy,singlecrystal X-ray diffraction,and X-ray absorption spectroscopy,along with density functional theory(DFT)calculations,the structure and dynamic behaviour of the active sites were thoroughly investigated under the synergistic influence of ligands and HCl.The results revealed that HCl activation induces a significant structural transformation of the active sites,leading to the formation of a hexacoordinate complex,Ru(CO)_(2)C_(12)(C_(6)H_(15)N·HCl)_(2).DFT calculations further elucidated the mechanism underlying active site formation,revealing that an increased electron density around the Ru centre and corresponding changes in its coordination environment play critical roles in enhancing catalyst stability and activity.This study contributes to a deeper understanding of the structural basis of active site evolution during acetylene hydrochlorination,offering both practical insights into industrial applications and foundational knowledge for advancing liquid-phase catalysis.
基金supported by the National Natural Science Foundation of China(21273076 and 21373089)the Open Research Fund of Top Key Discipline of Chemistry in Zhejiang Provincial Colleges and Key Laboratory of the Ministry of Education for Catalysis Materials(Zhejiang Normal University,ZJHX2013)Shanghai Leading Academic Discipline Project (B409)~~
文摘Pt nanoparticles entrapped in ordered mesoporous CMK-3 carbons with p6mm symmetry were prepared using a facile impregnation method, and the resulting materials were characterized using X-ray diffraction spectroscopy, N2 adsorption-desorption, scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. The Pt nanoparticles were highly dispersed in the CMK-3 with 43.7% dispersion. The Pt/CMK-3 catalyst was an effective catalyst for the liquid-phase hydrogenation of nitrobenzene and its derivatives under the experimental conditions studied here. The Pt/CMK-3 catalyst was more active than commercial Pt/C catalyst in most cases. A highest turnover frequency of 43.8 s-1 was measured when the Pt/CMK-3 catalyst was applied for the hydrogenation of 2-methyl-nitrobenzene in ethanol under optimal conditions. It is worthy of note that the Pt/CMK-3 catalyst could be recycled easily, and could be reused at least fourteen times without any loss in activity or selectivity for the hydrogenation of nitrobenzene in ethanol.
基金Supported by the National Natural Science Foundation of China （20576081, 20736009） and the Ph.D. Programs Foundation of Ministry of Education of China （20070610128）.
文摘Liquid phase oxidation of toluene is an environmental benign route for the production of benzoic acid.In a φ48mm bubble column reactor,the commercial process of toluene liquid phase oxidation was conducted with Co(CH3COO)2.4H2O as catalyst.The Co2+ concentration [Co2+] was determined by extraction spectrophotometry and hereby the Co3+ concentration [Co3+] was obtained by mass balance.The results showed that [Co3+] reached the maximum at about 25-30min.[Co3+] increased with increasing Co catalyst amount at total Co concentration<150 mg.L-1 of toluene.The conversion of toluene,yield and selectivity of benzoic acid increased with the increasing [Co3+/Co2+] max.A high [Co3+] and a high [Co3+]/[Co2+] ratio are beneficial to the reaction.
基金supported by the Natural Science Foundation of China (Grant No.50771084)the Natural Science Foundation of the Education Department of Jiangsu province,China (Grant No.09KJB430004)
文摘The homogeneous liquid was separated into two phases, （Fe, Co）-rich LI and Cu-rich L2, once the melt was undercooled below a liquid-phase separation temperature Tsep. If the duration from Tsep to Tsl （solidification temperature of LI phase）, termed the liquid-phase separation interval Δt, exceeded a critical value, an eggtype structure was observed. By utilizing differential thermal analyses （DTA）, the solidification process of the undercooled Fe-Co-Cu alloys was studied. Additionally, an immiscible boundary was obtained, which was a convex parabola with a symmetrical axis of XCu=0.52. Depending on the relative amounts of LI and L2, the minor phase was nucleated firstly to form liquid droplets and separated from the original liquids at the beginning of liquid-phase separation.
文摘The volatile and semi-volatile components in tobacco flavor additives were extracted by both simultaneous distillation extraction and solid-phase micro-extraction. Extraction conditions for solid-phase micro-extraction were optimized with information theory. Then, detection were accomplished by gas chromatography-mass spectrometry. Characteristic of each method was compared. Qualitative analysis and quantitative analysis of 6# tobacco flavor sample were accomplished through both simultaneous distillation extraction and solid-phase micro-extraction. The experimental results show that solid-phase micro-extraction method is the first choice for qualitative analysis and simultaneous distillation extraction is another good selection for quantitative analysis. By means of simultaneous distillation extraction, 20 components are identified, accounting for 92.77% of the total peak areas. Through solid-phase micro-extraction, there are 17 components identified accounting for 91.49% of the total peak areas. The main aromatic components in 6# tobacco flavor sample are propanoic acid, 2-hydroxy-, ethyl ester, menthol and menthyl acetate. The presented method has been successfully used for quality control of tobacco flavor.
基金the National Natural Science Foundation of China (Nos. 51502297, 51372248, and 51432009)Instrument Developing Project of the Chinese Academy of Sciences (No. yz201421)
文摘The liquid-phase furfural （FAL） hydrogenation to furfuryl alcohol （FOL） and tetrahydrofurfuryl alcohol （THFOL） was investigated using sulfonate group （-SO3H） grafted activated carbon （AC） supported Ni catalyst, which was prepared and activated simultaneously by liquid phase reduction method. This functionalized nickel catalyst demonstrated an enhanced catalytic performance for selective hydrogenation of FAL, in which almost 100% FOL （〈80℃） and THFOL （〉100℃） selectivity with complete conversion was obtained, respectively. More importantly, the conversion of transfer hydrogenation of FAL to FOL also can reach almost 100% under optimal conditions （140℃, 4.0h）. The effect of -SO3H was evaluated and systematically analyzed by the combination of reaction performance and physico-chemical characterizations. Cycling test proved the prepared catalyst could be recycled and reused for several times without noticeably reducing catalytic activity of hvdrogenation.
文摘The kinetics of liquid-phase hydrogenation of toluene catalyzed by MlNi_5 was studied by investigating the influences of the reaction temperature and pressure on the mass transfer-reaction processes inside the slurry. The results show that the reaction rate accelerates when the reaction temperature increases, and reaches its maximum at about 490 K, but if temperature is higher than 510 K, the reaction rate decreases rapidly. The whole reaction process is controlled by the reaction at the surface of the catalyst particles. The mass transfer resistance at gas-liquid interface and that from the bulk liquid phase to the surface of the catalyst particle can be neglected. The apparent reaction rate is zero order for toluene concentration and first order for hydrogen concentration in the liquid phase. The kinetic model is obtained. The kinetic model fits the experimental data very well. The apparent activation energy of the hydrogen absorption reaction of MlNi_5-toluene slurry system is 41.01 kJ·mol^(-1).
基金financially supported by ISSP RAS-Russian Government contracts
文摘The main problems with the liquid-phase technology of carbon fiber/aluminum matrix composites include poor wetting of the fiber with liquid aluminum and formation of aluminum carbide on the fibers’surface.This paper aims to solve these problems.The theoretical and experimental dependence of porosity on the applied pressure were determined.The possibility of obtaining a carbon fiber/aluminum matrix composite wire with a strength value of about 1500 MPa was shown.The correlation among the strength of the carbon fiber reinforced aluminum matrix composite,the fracture surface,and the degradation of the carbon fiber surface was discussed.
基金supported by the National Natural Science Foundation of China(No.20706039)the National Basic Research Program(973 Program) of China (No.2005CB221204)+1 种基金the Program for the Top Young Academic Leaders of Higher Learning Institutions of Shanxi of China in 2010the Young Scientific and the Technical Fund of Shanxi of China (No.2006021010)
文摘Cu-Zn-Al slurry catalysts were prepared using a complete liquid-phase preparation technology under different heat treatment atmospheres.The catalysts were characterized using X-ray diffraction,X-ray photoelectron spectroscope,and N2 adsorption-desorption.Their application in the single-step synthesis of dimethyl ether from syngas was also investigated.The results indicate that the type of heat treatment atmosphere has an influence on the Cu species and the Cu0/Cu＋ ratio on the catalyst surface.Moreover,the final Cu/Zn ratio on the catalyst surface is mainly dependent on the composition and reaction environment of the catalyst and less on the type of heat treatment atmosphere.The prepared catalysts can suppress sintering of active sites at high temperatures,and the type of heat treatment atmosphere mainly affects the capability of the catalyst for methanol synthesis.The catalysts perform best using N2 as the heat treatment atmosphere.
基金supported by the Institute of Science and High Technology and Environmental Sciences(No.1/1859)
文摘TiO2 nanowire arrays were successfully fabricated by liquid-phase deposition method using porous alumina templates. The obtained TiO2 nanowires were characterized using Raman spectroscopy, X-ray diffraction （XRD）, scanning electron microscopy （SEM）, field emission scanning electron microscopy （FE- SEM）, transmission electron microscopy （TEM）, and selected area electron diffraction （SAED） analysis. Results of electron microscopic observations indicated that the nanowires were smooth and uniform with a diameter of about 50-80 nm and several micrometers in length. SAED, Raman, and XRD mea- surements showed that TiO2 nanowires were single-crystalline with a pure rutile structure after heating at 800 ~C for 10 h. In this situation, the nanowire constituents grew preferentially along the 〈001〉 direction. Furthermore, the formation process and mechanistic study of the Ti02 nanowire arrays were proposed and discussed in detail. The nanowires are clearly produced by the deposition of TiO2 particles on the inner wall of the template nanochannels.
基金the financial support from the SINOPEC(No.2014310031600599)
文摘According to the characteristics of FCC diesel, a technology of liquid-phase hydrodesulfurization of the diesel in tubular reactors was proposed and lab-scale experiments were carried out. A kinetic model for the hydrodesulfurization process was developed and verified. The model was utilized to predict the sulfur content of products under different operating conditions. The effects of temperature, space velocity, pressure, and hydrogen concentration on the dcsulfurization rate were investigated.
基金Project(51202066)supported by the National Natural Science Foundation of ChinaProject supported by Scientific Research Fund of Hunan Provincial Science and Technology Department,China+1 种基金Project(2013-26)supported by the State Key Program of Jilin University,ChinaProject(2013001)supported by Key Laboratory of Ecological Impacts of Hydraulic-projects and Restoration of Aquatic Ecosystem,Minister of Water Resources,China
文摘Olivine LiFePO4/C nanowires have been successfully synthesized by a simple and eco-friendly solution preparation.The phase,structure,morphology and composition of the as-prepared products were characterized by powder X-ray diffraction(XRD),scanning electron microscopy(SEM),thermogravimetric and differential-thermogravimetric analysis(TG-DTA) and energy dispersive X-ray spectrometry(EDS) techniques,showing uniform nanowire shape of LiFePO4/C with a diameter of 80-150 nm and a length of several microns.The heat-treated LiFePO4/C nanowires show excellent electrochemical properties of specific discharge capacity,rate capacity and cycling stability.In particular,the LiFePO4/C nanowires heat-treated at 400 °C show preferable first discharge specific capacity of 161 mA·h/g at 0.1C rate,while the voltage platform is 3.4 V and the first discharge specific capacity is 93 mA·h/g at 20C rate.The specific capacity retention is 98% after 50 cycles at 5C rate.
基金financial support from the National Research Foundation of Korea(NRF)grant funded by the Korean government(Ministry of Science and ICT,NRF-2017R1A5A1015365)Creative-Pioneering Researchers Program through Seoul National University(2020)+3 种基金the Interdisciplinary Research Initiatives Programs by College of Engineering and College of Medicine,Seoul National Universitythe POSCO Science Fellowship of POSCO TJ Park Foundationthe support from the NRF funded by the Ministry of Education(2019R1F1A1059099 and 2020R1F1A1065856)the support from the research fund of Hanyang University(HY-2018-N)。
文摘Nanobubbles have attracted considerable attention in various industrial applications due to their exceptionally long lifetime and their potential as carriers at the nanoscale.The stability and physiochemical properties of nanobubbles are highly sensitive to the presence of surfactants that can lower their surface tension or improve their electrostatic stabilization.Herein,we report real-time observations of the dynamic behaviors of nanobubbles in the presence of soluble surfactants.Using liquid-phase transmission electron microscopy(TEM)with multi-chamber graphene liquid cells,bulk nanobubbles and surface nanobubbles were observed in the same imaging condition.Our direct observations of nanobubbles indicate that stable gas transport frequently occurs without interfaces merging,while a narrow distance is maintained between the interfaces of interacting surfactant-laden nanobubbles.Our results also elucidate that the interface curvature of nanobubbles is an important factor that determines their interfacial stability.
基金financially supported by the National Basic Research Program China(Nos.2010CB631200 and 2010CB631206)the National Natural Science Foundation of China(Nos.50971124,50904059,51071165,U1037601 and 51204156)
文摘A kind of Ni-Cr-Fe-B-Si system amorphous alloy was used as interlayer in transient liquid-phase bonding(TLP bonding)of polycrystalline superalloy K465.The bonding behavior,microstructure feature and the tensile properties of the joints were investigated.There are B-rich phase and Si-rich phase formed in the center of the seam after bonding at 1210℃for 30 min.The isothermal solidification is complete after bonding at 1210℃for 4 h.The relationship of the average width of the remnant eutectic zone and bonding time at 1210℃is nonlinear.The tensile strength of the bonded joint at room temperature and 900℃is comparable to that of K465 alloy.
基金National Natural Science Foundation of China(Grant No.81872996)Natural Science Foundation of Tianjin of China(Grant No.20JCYBJC00060).
文摘Quality control of ginseng currently is mainly based on ginsenoside analysis,but rarely focuses on the volatile organic components.In the current work,an untargeted metabolomics approach,by headspace solid-phase micro-extraction gas chromatography/mass spectrometry(HS-SPME-GC/MS),was elaborated and further employed to holistically compare the compositional difference of the volatile components simultaneously from 12 Panax herbal medicines,which included P.ginseng(PG),P.quinquefolius(PQ),P.notoginseng(PN),red ginseng(PGR),P.ginseng leaf(PGL),P.quinquefolius leaf(PQL),P.notoginseng leaf(PNL),P.ginseng flower(PGF),P.quinquefolius flower(PQF),P.notoginseng flower(PNF),P.japonicus(PJ),and P.japonicus var.major(PJvm).Chromatographic separation was performed on an HP-5MS elastic quartz capillary column using helium as the carrier gas,enabling good resolution within 1 h.We were able to characterize totally 259 volatile compounds,including 82 terpenes(T),46 alcohols(Alc),29 ketones(K),25 aldehydes(Ald),21 esters(E),and the others.By analyzing 90 batches of ginseng samples based on the untargeted metabolomics workflows,236 differential ions were unveiled,and accordingly 36 differential volatile components were discovered.It is the first report that simultaneously compares the compositional difference of volatile components among 12 Panax herbal medicines,and useful information is provided for the quality control of ginseng aside from the well-known ginsenosides.
文摘A rapid headspace single-drop micro-extraction（mix） gas chromatography mass spectrometry（SDMEGC -MS） for the analysis of the volatile compounds in Herba Asari was developed in this study.A mixed solvent of n-tridecane and butyl acetate（1：1） was finally used for the extraction at 70 C for 15 min with sample amount of 0.750 g and 100 mesh particle size.Under the determined conditions,the pound samples of Herba Asari were directly applied for the analysis.SDME-GC-MS,SPME-GC-MS and SD-GCMS methods were compared and the results showed that SDME-GC-MS method was a simple, inexpensive and effective way to measure the volatile compounds in Herba Asari and could be used for the analysis of volatile compounds in complex samples.
文摘The interfacial reactions in partial transient liquid-phase bonding of Si3N4 ceramics with Ti/Ni/Ti interlayers were studied by means of scanning electron microscopy （SEM）, energy dispersive spectrometry （EDS） and X-ray diffractometry （XRD）. It was shown that the interfacial structure of Si3N4/TiN/Ti5Si3+Ti5Si4 + Ni3Si/ （NiTi ） /Ni3Ti/ Ni was formed after bonding. The activation energies for TiN layer and the mixed reaction layer of Ti5Si3 + Ti5Si4 + Ni3Si are 546. 8 kJ/mol and 543. 9 kJ/mol, respectively. The formation and transition processes of interface layer sequence in the joint were clarified by diffusion path. An important characteristic, which is different from the conventional brazing and soid-state diffusion bonding, has been found, i. e., during the partial transient liquid-phase bonding, not only the reaction layers which have formed grow, but also the diffusion path in the subsequent reaction changes because of the remarkable variation of the concentration on the metal side.
基金Project(200805331062) supported by the Research Fund for the Doctoral Program of Higher Education of ChinaProject(2010FJ4061) supported by the Science and Technology Program of Hunan Province,China
文摘The 8% （mass fraction） yttrium-partially-stabilized zirconia （8YSZ） ceramic was fabricated via liquid phase sintering at 1 200-1 400℃ by adding different mass ratios of CuO-16.7%TiO2 （molar fraction） as sintering aid. Relative density, microstructure, Vickers hardness and bending strength as a function of sintering temperature and additive content were investigated. The experiment results show that liquid phase sintering at low temperature can be realized through adding CUO-16.7% TiO2 to 8YSZ. The Vickers hardness and bending strength of samples with sintering aid are generally much higher than those of samples without sintering aid for all sintering temperatures, and increase with the increase of sintering temperature. When the addition content of CUO-16.7% TiO2 is beyond 0.5%, the relative density, Vickers hardness and bending strength decrease with the increase of the mass ratio of sintering aid. Low additions of sintering aid are beneficial to aiding densification; high additions of sintering aid are detrimental to the sintered properties mainly due to greater amounts of pores generated by the volatilization of oxygen with the eutectic reaction between copper oxide and titanium dioxide. It is found that the fine grain size and high relative density are two main reasons of the high bending strength and Vickers hardness of the materials.
文摘An efficient poly(ethylene glycol) (PEG)-supported liquid-phase parallel approach to di(aryloxyacetyl)thiosemicarbazides is described. PEG-bound phenol reacted with chloroacetic acid to afford PEG-bound phenyloxyacetic acid, which was readily converted into corresponding phenyloxyacetyl chloride. Subsequent nucleophilic substitution with ammonium thiocyanate followed by addition of aryloxyacetic acid hydrazides gave PEG-bound di(aryloxyacetyl)thiosemi-carbazides, which were easily cleaved to give the resulting library of 1-aryloxyacetyl-4-(4'-methoxylcarbonylphenyloxyacetyl)thiosemicarbazides in good to high yield and high purity.
文摘Pt/CeO2–ZrO2–SnO2/γ-Al2O3 catalysts were prepared by co-precipitation and wet impregnation methods for catalytic oxidation of acetaldehyde to acetic acid in water. In the present catalysts, Pt and CeO2–ZrO2–SnO2 were successfully dispersed on the γ-Al2O3 support.Dependences of platinum content and reaction time on the selective oxidation of acetaldehyde to acetic acid were investigated to optimize the reaction conditions for obtaining both high acetaldehyde conversion and highest selectivity to acetic acid. Among the catalysts, a Pt（6.4 wt.%）/Ce0.68Zr0.17Sn0.15O2.0（16 wt.%）/γ-Al2O3 catalyst showed the highest acetaldehyde oxidation activity. On this catalyst, acetaldehyde was completely oxidized after the reaction at 0°C for 8 hr, and the selectivity to acetic acid reached to 95%and higher after the reaction for 4 hr and longer.
