ELECTROPHORESIS
·
2013
·Vol. 34
·期 6
·846-853
·
IF 3.261
Haizhi Zhang,Li Qi,Ying Shen,Juan Qiao,Lanqun Mao
Amino acid ionic liquids (AAILs) with l -lysine ( l -Lys) as anion were synthesized and applied as new chiral ligands in Zn(II) complexes for chiral ligand-exchange CE. After effective optimization, baseline enantioseparation of seven pairs of dansylated amino acids was achieved with a buffer of 100.0 mM boric acid, 5.0 mM ammonium acetate, 3.0 mM ZnSO 4 , and 6.0 mM [C 6 mim][ l -Lys] at pH 8.2. To validate the unique behavior of AAILs, a comparative study between the performance of Zn(II)- l -Lys and Zn(II)-[C 6 mim][ l -Lys] systems was conducted. In Zn(II)-[C 6 mim][ l -Lys] system, it has been found that the improved chiral resolution could be obtained and the migration times of the three test samples were markedly prolonged. Then the separation mechanism was further discussed. The role of [C 6 mim][ l -Lys] indicated clearly that the synthesized AAILs could be used as chiral ligands and would have potential utilization in separation science in future.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2012
·
IF 2.237
Duan-Jian Tao,Zhang-Min Li,Zheng Cheng,Na Hu,Xiang-Shu Chen
It is remarkable that Brønsted acidic ionic liquids (BAILs) have several unique advantages in the acid-catalysis reaction, which avoids the technical issues raised from mineral acids. The kinetics for the ketalization of cyclohexanone with glycol using BAILs as catalysts was therefore studied for the first time. The effects of various parameters such as kind of BAILs, temperature, catalyst loading, and molar ratio of the reactants on the conversion of cyclohexanone were examined in detail, and a pseudohomogeneous (PH) kinetic model was used successfully to correlate the experimental data in the temperature range from 313.15 to 343.15 K. The kinetic parameters such as reaction rate constant, activation energy, and chemical equilibrium constant then were proposed and utilized to interpret the catalytic activities of the BAILs catalysts. It was also validated from the comparison of catalytic performance among the BAILs, H2SO4, and solid resin that the BAILs were considered to be environmentally friendly and high efficient catalysts, and were suggested to replace mineral and solid acids in the synthesis of ketal.
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JOURNAL OF WUHAN UNIVERSITY OF TECHNOLOGY-MATERIALS SCIENCE EDITION
·
2014
·Vol. 29
·期 5
·1090-1097
·
IF 0.422
Tang Yimei,Hu Xiaoling,Guan Ping,Li Xiaoqian,Tian Tian
Several 1-vinyl-3-alkylimidazolium halogens [VRIM]X, which are functional materials with ethylenic bonds, were synthesized using the microwave-assisted synthesis method. Fourier transform infrared spectroscopy and 1H nuclear magnetic resonance spectroscopy were carried out to analyze the resultant structures. The electrochemical properties and solubility of [VRIM]Br were investigated and discussed in detail. The temperature dependence of pure [VRIM]Br over a wide temperature range of 298.15–323.15 K fitted the Arrhenius equation well. At certain low concentrations, the electrical conductivity of the [VRIM]Br solution significantly increased with increasing solution concentration. The electrical conductivities of the [VRIM]Br observed in water, methanol, and ethanol showed the trend σ
water > σ
methanol > σ
ethanol . Conductometry showed that the critical micelle concentrations of the bromines in water, methanol, and ethanol were 6.8–6.9 × 10 −6 , 1.4–1.5 × 10 −5 , and 1.9–2.0×10 −5 mol·L −1 , respectively; these results indicate that [VRIM]Br is an excellent surfactant. The solubility of [VRIM]X in common solvents was determined at 293.15 K, and results indicated that a decrease in solubility could be observed with decreasing dielectric constant of the solvent, elongation of the alkyl chain of the cation, and increasing anion size. Solubility parameters were also determined according to the Hildebrand-Scoff equation.
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Energy Technology
·
2015
·Vol. 3
·期 5
·509-517
·
IF 2.824
Lei Wang,Junning Zhang,Ziting Tan,Hong Jiang,Chunrong Xiong
Ionic liquids (ILs) were prepared in situ successfully on coconut shell activated carbon (AC) granules for biogas upgrading in a packed bed. In biogas upgrading, the saturated CO 2 capture capacities of AC-tethered 1-butyl-3-propylimidazolium bis(trifluoromethylsulfonyl)imide (AC-[BPIM][Tf 2 N]) and AC-tethered 1-aminoethyl-3-propylimidazolium bis(trifluoromethylsulfonyl)imide (AC-[EPIM-NH 2 ][Tf 2 N]) were 2.58 and 2.95 mmol g −1 at 20 °C and 0.5 MPa, respectively. The heat of adsorption was 23–28 kJ mol −1 for AC-[BPIM]-based adsorbents and 65–71 kJ mol −1 for AC-[EPIM-NH 2 ]-based ones. As a CO 2 concentration of less than 3 % is required for biogas to be used in a vehicle, an adsorption capacity at which 3 % of CO 2 is reached in the upgraded gas could be more important. If the flow rate of the inlet gas was 50 mL min −1 , the adsorption capacity at which 3 % of CO 2 is reached in the upgraded gas was 1.44 mmol g −1 for AC-[BPIM][Tf 2 N] and 1.95 mmol g −1 for AC-[EPIM-NH 2 ][Tf 2 N] at 20 °C and 0.2 MPa. The adsorption selectivities of CO 2 over CH 4 were ∼92 and 95 % for AC-[BPIM][Tf 2 N] and AC-[EPIM-NH 2 ][Tf 2 N], respectively. The immobilized ILs exhibited a relatively stable cyclability in a packed bed.
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CARBON
·
2014
·
IF 6.16
Lili Zhang,Jibin Pu,Liping Wang,Qunji Xue
The use of graphene and multi-walled carbon nanotubes (MWCNTs) additives as lubricants has received considerable interest because of their excellent mechanical and frictional properties . Given their structural differences, both carbon nano-additives are expected to have different synergistic effects at various conditions (from boundary to mixed lubrication). For applications in space, the tribological properties of graphene and MWCNTs additives in diamond-like carbon/ionic liquids hybrid films in different lubricating states at high vacuum were compared. The wear surfaces, transfer films, wear debris, and microstructures of the hybrid films were analyzed via Raman spectroscopy , X-ray photoelectron spectroscopy, and high-resolution transmission electron microscopy. The results showed that MWCNTs and graphene present the different nano-scale tribological mechanisms and produce different lubricating effect on the hybrid films at different lubricating states.
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Materials Science & Engineering C-Materials for Biological Applications
·
2014
·
IF 2.736
Yueting Wu,Lele Tang,Linhong Huang,Zhizhong Han,Jian Wang,Haibo Pan
In this study, we reported on a low detection limit penicillin biosensor with layer-by-layer (LbL) film containing single-graphene nanosheets (SGNs) preadsorbed with hematein, ionic liquids (ILs) and penicillinase. The penicillinase catalyzes the hydrolysis of penicillin to penicilloic acid, where H + is liberated and monitored amperometrically with hematein as a pH indicator. The SGN-hematein/ILs/penicillinase biosensor exhibited excellent performance for penicillin in PBS with a wide range from 1.25 × 10 − 13 to 7.5 × 10 − 3 M, and a low detection limit of 10 − 13 M (0.04 ppt, S/N ≥ 3). Furthermore, the detection of penicillin concentration in real sample (milk) had acceptable accuracy with the assay system.
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FUEL
·
2013
·
IF 3.357
Chenhua Shu,Tonghua Sun,Hongbo Zhang,Jinping Jia,Ziyang Lou
A novel integrated process of extraction with ionic liquid (IL) and reductive desulfurization by sodium borohydride (NaBH 4 ) was presented for gasoline desulfurization. The factors that influenced desulfurization efficiency were investigated and desulfurization efficiency reached more than 97% for model gasoline and more than 93% for real gasoline. The components of model gasoline after desulfurization were analyzed by gas chromatography/mass spectrometry (GC/MS) and the reaction routes of model sulfur compounds were proposed. The contents of sulfur, boron and nickel in aqueous solutions were analyzed by Chinese standard method or inductively coupled plasma (ICP). Furthermore, the structures of original and recycled ILs were analyzed by nuclear magnetic resonance (NMR) and the desulfurization performance of recycled ILs was investigated. Results indicated that ILs maintained their original structures after regeneration. Finally, desulfurization kinetics was also probed and results showed that desulfurization reactions of both model sulfur compounds and real gasoline could be treated as pseudo-first-order reactions.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2013
·
IF 2.206
Duan-Jian Tao,Fan Ouyang,Zhang-Min Li,Na Hu,Zhen Yang,Xiang-Shu Chen
Four tetrabutylphosphonium carboxylate ionic liquids ([P4444][CA]) were prepared, characterized, and used as catalysts for the synthesis of propylene glycol methyl ether (PGME) from the alcoholysis reaction of propylene oxide (PO) with methanol. The effects of various parameters such as the kind of ILs, temperature, reaction time, catalyst loading, and molar ratio of the reactants on PGME yield and selectivity were also studied in detail. The results indicated that tetrabutylphosphonium butyrate ([P4444][Buty]) exhibited the best catalytic activity in comparison to three other carboxylate ILs, and PGME was produced in nearly 94% yield under mild conditions. In addition, [P4444][Buty] was found to exhibit good catalytic activities and selectivities in other alcoholysis reactions of epoxides with various alcohols, such as PO with n-propanol, PO with n-butanol, 1-(allyloxy)-2,3-epoxypropane with methanol, and 1,2-epoxybutane with methanol. [P4444][Buty] could also be recovered easily and used repetitively at least 10 times without an obvious decrease in activity and quantity. Therefore, [P4444][Buty] proved to be an effective recyclable homogeneous catalyst for the synthesis of PGME and showed potential application in industry.
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GREEN CHEMISTRY
·
2013
·Vol. 16
·期 3
·1436-1443
·
IF 6.828
Guofeng Wang,Zhanquan Zhang,Linhua Song
The production of alkyl levulinates from furfuryl alcohol (FAL) in alcohol media was investigated at moderate temperature in the presence of Brønsted acidic ionic liquids. The reaction was examined and optimized under batch conditions, where it was found that furfuryl alcohol was rapidly and almost quantitatively converted into intermediate products including 2-alkoxymethylfuran and 4,5,5-trialkoxypentan-2-one, and high alkyl levulinates yield of 95% can be achieved after reaching a steady state in 2 h. An advantage of this catalyst system is that undesired dialkyl ether (DEE) formed by a side reaction of the dehydration of alcohol is negligible. The Hammett method was used to determine the acidities of these ionic liquids, which indicated that the acidity and the molecular structure have strong effects on the catalytic activity of ionic liquids. Based on the experimental results, a possible mechanism for the alcoholysis of FAL is proposed.
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CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2014
·
IF 0.872
Zhijian HE,Xiaomin WANG,Tian YAO,Hang SONG,Shun YAO
Four novel benzothiazolium ionic liquids with PF − 6 ([C 1 Bth][PF 6 ], [C 4 Bth][PF 6 ], [C 5 Bth][PF 6 ] and [C 6 Bth][PF 6 ]) were synthesized, and the rang of their melting points were determined between 358.35 K–424.05 K. The relationship of their melting points and the length of the straight alkyl chain on cation reflected ‘S’ type tendency. Then, the solubilities of the four ionic liquids in six lower alcohols (methanol, ethanol, 1-propanol, 2-propanol, 1-butanol and 2-methyl-1-propanol) were measured in the temperature rang of 253.15–383.15 K at atmospheric pressure with static analytical method, respectively. It was found that [C 6 Bth][PF 6 ] in all investigated ionic liquids had the largest solubility in six alcohols and the solubility of [C 4 Bth][PF 6 ] in methanol was very sensitive for temperature in 313.15–333.15 K, which was so-called “temperature-sensitivity”. This feature is of great significance to their application of catalyzing reaction or extraction process, and makes the recovery and reuse of ionic liquids (ILs) become easier. Moreover, the experimental solubility data were correlated with the modified Apelblat equation and λ h equation, respectively. It was found that the result of correlation using two divided temperature ranges was better than that of using the whole temperature range.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2013
·
IF 2.206
Ying Tian,Xuan Meng,Li Shi
The novel ionic liquids with an alkane sulfonic acid group were prepared and used for removal of trace olefins from aromatics (referred to as oil). The structures and acidities of the ionic liquids were experimentally characterized and systematically analyzed. The influences of various reaction parameters, such as the stirring speed, viscosities of the ionic liquids, molar fraction of ZnCl2, dosage and type of ionic liquid, reaction temperature, reaction time, and the reusability of the ionic liquid, were investigated. It was found that the ionic liquid 1-(3-sulfopropyl)-3-methylimidazolium bromochlorozincinate ([C3SO3Hmim]Br-ZnCl2) with the molar fraction of ZnCl2 of 0.67 exhibited a better performance for olefin removal. Meanwhile, the experimental results showed that after the reaction had taken place at 373 K for 1 h, olefin conversion of 29.54% was obtained with the mass ratio of IL to oil of 0.2. Even though the reusability of the ionic liquid was not good, the separation of the reaction mixture can be performed by simple decantation.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2014
·
IF 2.235
Fang Ding,Junjie Zheng,Yaqian Chen,Kaihong Chen,Guokai Cui,Haoran Li,Congmin Wang
A series of dual functionalized ionic liquids with metal chelate cations from surfactant and alkali metal salt were designed, prepared, and used for SO2 capture. The effect of metal ions, coordination number, anionic structures, temperature, and pressure on SO2 absorption was investigated. The interaction of these functionalized ionic liquids with SO2 was explained by spectroscopic investigation. The results showed that these metal-containing ionic liquids exhibited high absorption capacity through a combination of physical and chemical interaction of SO2 with basic anions and ether-containing cations as well as excellent reversibility (21 recycles). Considering the easy preparation, low cost, and excellent performance, these dual functionalized metal-containing ionic liquids provide significant improvements over traditional ionic liquids, indicating the promise for industrial application in SO2 capture.
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