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Supercritical carbon dioxide extraction of CLA-ethyl ester

Yingdi CHEN, Peng XU, Jian CHENG

《化学科学与工程前沿(英文)》 2011年 第5卷 第1期   页码 102-106 doi: 10.1007/s11705-010-0536-3

摘要: Supercritical carbon dioxide (SC-CO ) extraction of Conjugated linoleic acid (CLA) ethyl ester was investigated at pressures in the range of 9 to 10.5 MPa and temperature gradients ranging from 0°C to 21°C. The content of CLA-ethyl ester in the fraction was analyzed with gas chromatography (GC). The experimental results indicated that the rate of extraction would rise with the increase of pressure when temperature gradient was given. Moreover, the extraction pressure had insignificant influence on the selectivity of CLA-ethyl ester in SC-CO . When pressure was fixed, setting certain temperature gradient can improve the selectivity of CLA-ethyl ester in SC-CO , and CLA-ethyl ester can be concentrated more effectively than without a temperature gradient. The acid value and peroxide value of the fractions were reduced obviously, compared to the raw material. The optimal condition is pressure at 10 MPa and temperature gradient at 11°C.

关键词: supercritical carbon dioxide     extraction     CLA-ethyl ester     temperature gradient    

Modeling of Ce(IV) transport through a dispersion flat combined liquid membrane with carrier P507

Liang PEI,Liming WANG,Zhanying MA

《环境科学与工程前沿(英文)》 2014年 第8卷 第4期   页码 503-509 doi: 10.1007/s11783-013-0540-1

摘要: A mathematical model for the transport of Ce(IV) from hydrochloric acid solutions through dispersion flat combined liquid membrane (DFCLM) with contain 2-ethyl hexyl phosphonic acid-mono-2-ethyl hexyl ester (P507) as the carrier, dissolved in kerosene as the membrane solution have been studied. This process of facilitated transport, based on membrane technology, is a variation on the conventional technique of solvent extraction and may be described mathematically using Fick’s second law. The equations for transport velocity are derived considering the diffusion of P507 and its metallic complexes through the liquid membrane. In this work, the system is considered to be in a transient state, and chemical reaction between Ce(IV) and the carrier to take place only at the solvent–aqueous interfaces. Model concentration profiles are obtained for the Ce(IV), from which extraction velocities are predicted. The experimental and simulated Ce(IV) extractions showed similar tendencies for a high Ce(IV) concentration and acidity case.The model results indicate that high initial Ce(IV) concentrations and acidity both have detrimental effects on Ce(IV) extraction and stripping. The diffusion coefficient of Ce(IV) in the membrane and the thickness of diffusion layer between feed phase and membrane phase are obtained and the values are 6.31 × 10 m ·s and 31.2 μm, respectively. The results are in good agreement with experimental results.

关键词: Dispersion flat combined liquid membrane (DFCLM)     dispersion phase     feed phase     2-ethyl hexyl phosphonic acid-mono-2-ethyl hexyl ester     Ce (IV)    

CLA的生理活性和应用前景

张根旺,郭诤,杨天奎

《中国工程科学》 2001年 第3卷 第7期   页码 85-89

摘要:

CLA是20世纪80年代末才被发现具有许多重要生理活性的天然脂肪酸,文章讨论了CLA的涵义界定、天然存在、重要的生理活性及其应用前景。

关键词: CLA     生理活性     应用前景    

Toughening of vinyl ester resins by two-dimensional MXene nanosheets

《化学科学与工程前沿(英文)》   页码 1651-1658 doi: 10.1007/s11705-022-2208-5

摘要: Two-dimensional nanosheets are highly effective tougheners for vinyl ester resins. The toughening effect is related to the high specific surface area and unique two-dimensional planar structure of the nanosheets. In this study, a coupling agent γ-(2,3-epoxypropoxy) propytrimethoxysilane (Kh-560) was used to modify MXene nanosheets (M-MXene) for use in toughening vinyl ester resin. The mechanical properties, including the tensile strength, flexural strength, Young’s modulus and elongation, of neat vinyl ester resin and vinyl ester resin modified with MXene and M-MXene were investigated. The results showed that modification significantly improved the mechanical properties of the vinyl ester resin. The tensile and flexural strengths of the MXene-nanosheet-modified vinyl ester resin were 27.20% and 25.32% higher, respectively, than those of the neat vinyl ester resin. The coupling agent improved the interfacial compatibility between the MXene nanosheets and vinyl ester resin, which resulted in the tensile and flexural strengths of the M-MXene-nanosheet-modified vinyl ester resin being 52.57% and 54.60% higher, respectively, than those of the neat vinyl ester resin for a loading quantity of nanosheets of only 0.04 wt %, which is economically viable. The main mechanisms by which the nanosheets toughen the resin are crack deflection and crack pinning.

关键词: MXene nanosheets     2D material     vinyl ester resin     modification     coupling agent    

The prediction of adsorption isotherms of ester vapors on hypercrosslinked polymeric adsorbent

Liuyan WU,Lijuan JIA,Xiaohan LIU,Chao LONG

《环境科学与工程前沿(英文)》 2016年 第10卷 第3期   页码 482-490 doi: 10.1007/s11783-015-0826-6

摘要: Adsorption isotherms of methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate and ethyl propionate on hypercrosslinked polymeric resin (ND-100) were measured at 303K, 318K and 333K,respectively, and well fitted by Dubinin–Astakhov (DA) equation. The plots of the adsorbed volume ( ) versus the adsorption potential ( ) at three different temperatures all fell basically onto one single curve for every ester. A predicted model based on DA equation was obtained on the basis of adsorption equilibrium data of methyl acetate, ethyl acetate and ethyl propionate at 318K. The model equation successfully predicted the adsorption isotherms of methyl acetate, ethyl acetate and ethyl propionate on ND-100 at 303K, and 333K, and also gave accurate predictive results for adsorption isotherms of the other two ester compounds (propyl acetate and isopropyl acetate) on ND-100 at 303K, 318K and 333K. The results proved the effectiveness of DA model for predicting the adsorption isotherms of ester compounds onto ND-100. In addition, the relationship between physico-chemical properties of adsorbates and their adsorption properties was also investigated. The results showed that molecular weight, molar volume and molar polarizability had good linear correlations with the parameter (which represents adsorption characteristic energy) of DA equation.

关键词: hypercrosslinked polymeric adsorbent     adsorption isotherm     ester     prediction    

Reaction and characterization of crosslinking hyperbranched poly (amine-ester) with succine anhydride

XIAO Ling, WEI Xiuzhen, ZHU Baoku

《化学科学与工程前沿(英文)》 2007年 第1卷 第4期   页码 355-359 doi: 10.1007/s11705-007-0064-y

摘要: Basing on hydroxyl terminated hyperbranched poly (amine-ester)s (HPAEs), the cross-linking reactions and preparation of ester-crosslinked HPAE films were investigated using succine anhydride (SA) as crosslink reagent. It was proved that the cross-linking reaction between HPAE and SA followed a two-step mechanism. This mechanism provides an efficient route to prepare HPAE/SA cross-linked films, in which, the precursor films were prepared by casting HPAE/SA solution at a lower temperature, and then curing the films at a higher temperature. By varying SA content, the solid HPAE/SA films with different cross-linking degrees were prepared successfully. The highest tensile strength of the cross-linked film could reach 59.60 MPa. With all water contact angle smaller than 74.3°, the crosslinked films demonstrated good hydrophilic properties.

关键词: different cross-linking     amine-ester     temperature     crosslinked     efficient    

Effect of exhaust gas recirculation and ethyl hexyl nitrate additive on biodiesel fuelled diesel engine

K. VENKATESWARLU, B. S. R MURTHY, V. V. SUBBARAO, K. Vijaya KUMAR

《能源前沿(英文)》 2012年 第6卷 第3期   页码 304-310 doi: 10.1007/s11708-012-0195-9

摘要: Cetane improvers reduce the ignition delay, which in turn reduces the combustion temperatures thereby reduce NO emissions. Exhaust gas recirculation (EGR) proved to be an effective way to reduce the NO emissions. In this present experimental work, a combination of exhaust gas recirculation and cetane improver ethyl hexyl nitrate (EHN) is used to investigate the performance and exhaust emissions of a single cylinder four stroke naturally aspirated direct injection and air cooled diesel engine. Test results show that the brake thermal efficiency increases with the increase in the percentage of EGR which is accompanied by a reduction in brake specific fuel consumption and exhaust gas temperatures, and that bio-diesel with cetane improver under 20% EGR reduces NO emissions by 33% when compared to baseline fuel without EGR. However carbon monoxide (CO), hydro carbon (HC) and smoke emissions increase with an increase in percentage of EGR.

关键词: additive     exhaust gas recirculation (EGR)     emissions     ethyl hexyl nitrate (EHN)     performance    

Catalytic oxidation of carbon monoxide, toluene, and ethyl acetate over the

Zhidan Fu, Lisha Liu, Yong Song, Qing Ye, Shuiyuan Cheng, Tianfang Kang, Hongxing Dai

《化学科学与工程前沿(英文)》 2017年 第11卷 第2期   页码 185-196 doi: 10.1007/s11705-017-1631-5

摘要: The Pd catalyst supported on cryptomelane-type manganese oxide octahedral molecular sieve (OMS-2) were prepared. The effect of Pd loading on the catalytic oxidation of carbon monoxide, toluene, and ethyl acetate over Pd/OMS-2 has been investigated. The results show that the Pd loading plays an important role on the physicochemical properties of the Pd/OMS-2 catalysts which outperform the Pd-free counterpart with the 0.5Pd/OMS-2 catalyst being the best. The temperature for 50% conversion was 25, 240 and 160 °C, and the temperature for 90% conversion was 55, 285 and 200 °C for oxidation of CO, toluene, and ethyl acetate, respectively. The low-temperature reducibility and high oxygen mobility of Pd/OMS-2 are the factors contributable to the excellent catalytic performance of 0.5Pd/OMS-2.

关键词: cryptomelane-type manganese oxide octahedral molecular sieve     oxygen mobility     reducibility     carbon monoxide oxidation     volatile organic compound combustion    

Energy-efficient recovery of tetrahydrofuran and ethyl acetate by triple-column extractive distillation

Ao Yang, Yang Su, Tao Shi, Jingzheng Ren, Weifeng Shen, Teng Zhou

《化学科学与工程前沿(英文)》 2022年 第16卷 第2期   页码 303-315 doi: 10.1007/s11705-021-2044-z

摘要: An energy-efficient triple-column extractive distillation process is developed for recovering tetrahydrofuran and ethyl acetate from industrial effluent. The process development follows a rigorous hierarchical design procedure that involves entrainer design, thermodynamic analysis, process design and optimization, and heat integration. The computer-aided molecular design method is firstly used to find promising entrainer candidates and the best one is determined via rigorous thermodynamic analysis. Subsequently, the direct and indirect triple-column extractive distillation processes are proposed in the conceptual design step. These two extractive distillation processes are then optimized by employing an improved genetic algorithm. Finally, heat integration is performed to further reduce the process energy consumption. The results indicate that the indirect extractive distillation process with heat integration shows the highest performance in terms of the process economics.

关键词: extractive distillation     solvent selection     conceptual design     process optimization     heat integration    

Synthesis and bulk polymerization kinetics of monomer dehydroabietic acid-(2-acryloyloxy-ethoxy)-ethylester

Haibo ZHANG,Yanping YANG,He LIU,Jie SONG,Shibin SHANG,Zhanqian SONG

《农业科学与工程前沿(英文)》 2017年 第4卷 第1期   页码 97-105 doi: 10.15302/J-FASE-2016115

摘要: A bulk polymerization monomer dehydro- abietic acid-(2-acryloyloxy-ethoxy)-ethyl ester (DHA-DG-AC) was synthesized from dehydroabietic acid (DHA). The chemical structure of DHA-DG-AC was characterized by H NMR, C NMR, MS and FT-IR. The kinetics of the bulk polymerization of DHA-DG-AC was investigated by Differential Scanning Calorimeter (DSC). Two kinds of kinetic model (nth-order model and autocatalytic model) were used to investigate the polymerization process. The results showed that the experimental DSC curves were consistent with the computational data generated by the autocatalytic kinetic model, and the value of was 95.73 kJ·mol .

关键词: dehydroabietic acid     bulk polymerization     kinetics     autocatalytic kinetic model    

A comparison of the biological activities of ethyl acetate fractions from the stems and leaves of

Zhaolei WANG, Kai JIANG, Qinchao DING, Shujun LIU, Xiaobing DOU, Bin DING

《农业科学与工程前沿(英文)》 2020年 第7卷 第4期   页码 505-512 doi: 10.15302/J-FASE-2019271

摘要:

Pursh (PCP) is a popular traditional medicinal plant in China, widely used for the treatment of a variety of liver diseases. Although it has been long recognized that the main active elements of PCP are contained in ethyl acetate fraction (EAF), little is known so far in terms of the relative effectiveness of EAF derived from the stems versus leaves of this plant. In the current study, we prepared EAF by reflux extraction and sequential extraction from the stems (SEAF) and leaves (LEAF) of PCP and tested their hepatoprotective efficacies. The extract rates and flavonoid contents of LEAF were higher than those of SEAF. EAFs (>50 μg·mL ) prevented lipid accumulation in cells and protected against lipotoxicity injury when the concentration exceeded 25 μg·mL . More than 95% free radicals released by 2,2-diphenyl-1-picrylhydrazyl (DPPH) were eliminated by 25 μg·mL SEAF and 50 μg·mL LEAF, respectively. Further, EAFs (25 μg·mL ) also showed protective antioxidant effects, with the activity of LEAF being significantly higher than that of SEAF. EAFs (10 mg·mL ) also showed similar unspecific bacteriostatic activity. In comparison with SEAF, LEAF contained more flavonoids and had a higher anti-oxidation capability and for these reasons we suggest it should be better for clinical use.

关键词: antibacterial     anti-oxidation     lipid accumulation     lipotoxicity     Penthorum chinense Pursh    

用于锂离子电池的富醚/酯/氟黏结剂配方 Article

Xianqing Zeng, Donglin Han, Zeheng Li, Hongxun Wang, Gu Wu, Yong Deng, Kai Liu, Li Xie, Chengdu Liang, Min Ling, Yuchuan Huang

《工程(英文)》 2022年 第19卷 第12期   页码 199-206 doi: 10.1016/j.eng.2022.05.020

摘要:

由于硅阳极体积膨胀过大,无法在高能量密度电池中实现实际应用。研究人员一直专注于在阳极中添加黏结剂以限制体积膨胀,来解决这一问题,因为黏结剂的氢键和机械性能可以用来增强黏附力和适应硅阳极的体积变化。在这里,我们综合考虑了黏结剂的氢键、力学性能、稳定性以及与电解液的相容性,设计了一种富醚/酯/氟的复合聚合物P(TFEMA-co-IBVE)。该黏结剂配方具有优异的稳定性、黏结性和机械强度,能够适应硅电极体积的剧烈变化,表现出优异的电化学性能,面积容量高达5.4 mA∙h∙cm−2。这种新型聚合物设计可应用于下一代锂离子电池的其他电极材料。

关键词: 硅阳极     乳液共聚合     氟原子            

Potential hybrid feedstock for biodiesel production in the tropics

Solomon GIWA,Oludaisi ADEKOMAYA,Collins NWAOKOCHA

《能源前沿(英文)》 2016年 第10卷 第3期   页码 329-336 doi: 10.1007/s11708-016-0408-8

摘要: Recently, mixture of different oils at various proportions have been used as feedstock for biodiesel production. The primary aim is to improve fuel properties which are strongly influenced by the fatty acid composition of the individual oil that makes up the feedstock mix. The tropics are renowned for abundant oil-bearing crops of which palm kernel oil (PKO) from palm seed and groundnut oil (GNO) are prominent. This present paper investigated biodiesel production from hybrid oil (HO) of PKO (medium carbon chain and highly saturated oil) and GNO (long carbon chain and highly unsaturated oil) at 50/50 (v/v) blending. The principal fatty acids (FAs) in the HO are oleic (35.62%) and lauric acids (24.23%) with 47.80% of saturated FA and 52.26% of unsaturated FA contents. The chemical conversion of the oil to methyl ester (ME) gave 86.56% yield. Fuel properties of hybrid oil methyl ester (the HOME) were determined in accordance with standard test methods and were found to comply with both ASTM D6751 and EN 14214 standards. The oxidative stability, cetane number and kinematic viscosity (KV) of HOME were observed to be improved when compared with those of GNO methyl ester from single parent oil, which could be accredited to the improved FA composition of the HO. The KV (3.69 mm /s) of HOME obtained in this paper was remarkably low compared with those reported in literature for most biodiesels. This value suggests better flow, atomization, spray and combustion of this fuel. Conclusively, the binary blend of oils can be a viable option to improve the fuel properties of biodiesel feedstock coupled with reduced cost.

关键词: groundnut oil     palm kernel oil     methyl ester     fuel properties     tropics     fatty acid composition    

Ternary phase behavior of water microemulsified diesel-palm biodiesel

Nurul Atiqah Izzati MD ISHAK,Ismail Ab RAMAN,Mohd Ambar YARMO,Wan Mohd Faizal WAN MAHMOOD

《能源前沿(英文)》 2015年 第9卷 第2期   页码 162-169 doi: 10.1007/s11708-015-0355-9

摘要: This paper aims to develop a new microemulsions system comprising diesel and palm oil methyl ester (PME) that have the potential to be used as alternative fuels for diesel engines. The water-in-diesel-biodiesel microemulsions were prepared by applying PME mixed with diesel, non-ionic surfactants, co-surfactants and water to make the water-in-oil (W/O) microemulsion system. This microemulsified fuel was achieved through low-energy microemulsification by using the constant composition method. The diesel used was mixed with four different concentrations of PME, i.e., 10% (w/w) (B10), 20% (w/w) (B20), 30% (w/w) (B30) and neat diesel (B0). The amount of water was fixed at 20% (w/w). The phase behavior of the water/mixed non-ionic surfactant/diesel-PME system were studied by constructing pseudoternary phase diagrams with the goal of formulating optimized systems. The results showed that the microemulsions were formed and stabilized with a mixture of non-ionic surfactants at a weight ratio of 80:20 at 20% (w/w), and with mixed co-surfactants at a weight ratio of 25:75, 20:80 and 10:90 for B0, B10, B20 and B30 respectively. The particle size, kinematic viscosity at 40°C, refractive index, density, heating value, cloud point, pour point and flash point of the selected water-in-diesel microemulsion were 19.40 nm (polydispersity of 0.12), 2.86 mm /s, 1.435, 0.8913 g/mL, 31.87 MJ/kg, 7.15°C, 10.5°C and 46.5°C respectively. The corresponding values of the water-in-diesel-PME selected were 20.72 nm to 23.74 nm, 13.02 mm /s to 13.29 mm /s, 1.442, 0.8939 g/mL to 0.8990 g/mL, 31.45 MJ/kg to 27.34 MJ/kg, 7.2°C to 6.8°C, 8.5°C to 1.5°C and 47.5°C to 52.0°C. These preliminary findings were further studied as potential fuels for diesel engines.

关键词: palm methyl ester     palm oil biodiesel     microemulsion     water microemulsified fuels    

Methyl acetate–methanol mixture separation by extractive distillation: Economic aspects

Elena Graczová, Branislav Šulgan, Samuel Barabas, Pavol Steltenpohl

《化学科学与工程前沿(英文)》 2018年 第12卷 第4期   页码 670-682 doi: 10.1007/s11705-018-1769-9

摘要:

Methyl acetate is considered low toxicity volatile solvent produced either as a by-product during methanol carbonylation or via acetic acid esterification with methanol. In both cases, pure methyl acetate has to be isolated from the reaction mixture. Simulation of methyl acetate separation from its mixture with methanol by extraction distillation was carried out in ASPEN+ software. In total three case studies were assumed using two different extraction solvents and two solvent regeneration strategies. In case A, novel extraction solvent 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ionic liquid, was considered. Raw material separation was achieved in an extraction distillation column while the solvent regeneration was accomplished in a second distillation column in this case. In case study B, the same extraction solvent was used; however, its regeneration was carried out in a single-effect evaporator. Dimethyl sulfoxide was the second extraction solvent selected. Its use in methyl acetate-methanol separation is presented in case study C. As high purity of dimethyl sulfoxide was required for the methyl acetate-methanol azeotrope breaking, its regeneration was carried out in the second distillation column only. To simulate the ternary methyl acetate–methanol–extraction solvent mixtures separation, vapor–liquid equilibrium was predicted based on the NRTL equation. Further, unknown properties of the considered ionic liquid and variation of these properties with temperature were predicted and introduced into the ASPEN+ components properties database. Based on these data, optimum operation parameters of the respective separation equipment were established. In all case studies, the same condition had to be fulfilled, namely minimum methyl acetate content in the distillate from the extraction distillation column of 99.5mol-%. Results of simulations using the respective optimum operation parameters were employed in the economic evaluation of the three separation unit designs studied. It was found that the least energy-demanding design corresponds to the case study B in terms of both capital as well as operation expenses.

关键词: methyl acetate     1-ethyl-3-methylimidazolium trifluoromethanesulfonate     extraction distillation     dimethyl sulfoxide     economic evaluation    

标题 作者 时间 类型 操作

Supercritical carbon dioxide extraction of CLA-ethyl ester

Yingdi CHEN, Peng XU, Jian CHENG

期刊论文

Modeling of Ce(IV) transport through a dispersion flat combined liquid membrane with carrier P507

Liang PEI,Liming WANG,Zhanying MA

期刊论文

CLA的生理活性和应用前景

张根旺,郭诤,杨天奎

期刊论文

Toughening of vinyl ester resins by two-dimensional MXene nanosheets

期刊论文

The prediction of adsorption isotherms of ester vapors on hypercrosslinked polymeric adsorbent

Liuyan WU,Lijuan JIA,Xiaohan LIU,Chao LONG

期刊论文

Reaction and characterization of crosslinking hyperbranched poly (amine-ester) with succine anhydride

XIAO Ling, WEI Xiuzhen, ZHU Baoku

期刊论文

Effect of exhaust gas recirculation and ethyl hexyl nitrate additive on biodiesel fuelled diesel engine

K. VENKATESWARLU, B. S. R MURTHY, V. V. SUBBARAO, K. Vijaya KUMAR

期刊论文

Catalytic oxidation of carbon monoxide, toluene, and ethyl acetate over the

Zhidan Fu, Lisha Liu, Yong Song, Qing Ye, Shuiyuan Cheng, Tianfang Kang, Hongxing Dai

期刊论文

Energy-efficient recovery of tetrahydrofuran and ethyl acetate by triple-column extractive distillation

Ao Yang, Yang Su, Tao Shi, Jingzheng Ren, Weifeng Shen, Teng Zhou

期刊论文

Synthesis and bulk polymerization kinetics of monomer dehydroabietic acid-(2-acryloyloxy-ethoxy)-ethylester

Haibo ZHANG,Yanping YANG,He LIU,Jie SONG,Shibin SHANG,Zhanqian SONG

期刊论文

A comparison of the biological activities of ethyl acetate fractions from the stems and leaves of

Zhaolei WANG, Kai JIANG, Qinchao DING, Shujun LIU, Xiaobing DOU, Bin DING

期刊论文

用于锂离子电池的富醚/酯/氟黏结剂配方

Xianqing Zeng, Donglin Han, Zeheng Li, Hongxun Wang, Gu Wu, Yong Deng, Kai Liu, Li Xie, Chengdu Liang, Min Ling, Yuchuan Huang

期刊论文

Potential hybrid feedstock for biodiesel production in the tropics

Solomon GIWA,Oludaisi ADEKOMAYA,Collins NWAOKOCHA

期刊论文

Ternary phase behavior of water microemulsified diesel-palm biodiesel

Nurul Atiqah Izzati MD ISHAK,Ismail Ab RAMAN,Mohd Ambar YARMO,Wan Mohd Faizal WAN MAHMOOD

期刊论文

Methyl acetate–methanol mixture separation by extractive distillation: Economic aspects

Elena Graczová, Branislav Šulgan, Samuel Barabas, Pavol Steltenpohl

期刊论文