JOURNAL OF CHROMATOGRAPHY A
·
2015
·
IF 4.169
Kexin Hou,Fengli Chen,Yuangang Zu,Lei Yang
An efficient method for the extraction of vitexin , vitexin-4″- O -glucoside, and vitexin-2″- O -rhamnoside from Phyllostachys edulis leaves comprises heat treatment using an ionic liquid–lithium salt mixture (using 1-butyl-3-methylimidazolium bromide as the solvent and lithium chloride as the additive), followed by ultrasound-assisted extraction. To obtain higher extraction yields, the effects of the relevant experimental parameters (including heat treatment temperature and time, relative amounts of 1-butyl-3-methylimidazolium bromide and lithium chloride, power and time of the ultrasound irradiation, and the liquid–solid ratio) are evaluated and response surface methodology is used to optimize the significant factors. The morphologies of the treated and untreated P. edulis leaves are studied by scanning electron microscopy. The improved extraction method proposed provides high extraction yield, good repeatability and precision, and has wide potential applications in the analysis of plant samples.
研究领域:
植物化学
·
分析化学
✓ 已验证
DOI
PubMed
高影响因子
POLYMER DEGRADATION AND STABILITY
·
2011
·
IF 2.594
Qin Chen,Wenjun Xiao,Lilong Zhou,Tinghua Wu,Ying Wu
Hydrolysis of chitosan in ionic liquids was carried out under microwave irradiation (MW) using sulfonic acid-functionalized ionic liquids (SFILs) as catalysts. The effect of microwave power, irradiation time, dosage of SFILs and DMSO was investigated by orthogonal tests. Under the optimal reaction conditions, the yield of total reducing sugars (TRS) reached over 90% within 2 min. The viscosity-average molecular weight of degraded chitosan was determined by viscosity method. The structures of the original and degraded chitosan were characterized by Fourier-transform infrared (FTIR) spectra, X-ray powder diffraction (XRD) analysis and carbon-13 nuclear magnetic resonance spectroscopy ( 13 C NMR). The influence of microwave power and irradiation time on the TRS and M v was further studied. This method can dramatically reduce reaction time.
研究领域:
生物化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Soft Matter
·
2024
·Vol. 20
·期 37
·7420-7428
·
IF 2.9
Yue Pan,Chunhua Zhao,Ruirui Wang,Mingjie Zhu,Wenchang Zhuang,Qintang Li
The structure of ionic liquids (ILs) has an influence on their physiochemical properties, determining their performance as self-assembly media. In this study, we focus on the anion effect of aprotic ionic liquids (AILs). The aggregation behaviours of the cationic surfactant 1-hexadecyl-3-methylimidazolium bromide (C16mimBr) have been investigated in the imidazolium AILs with the 1-ethyl-3-methyl imidazolium cation and different anions, including nitrate, ethylsulfate, bis(trifluoromethylsulfonyl) imide and tetrafluoroborate. Surface adsorption parameters of C16mimBr were determined using surface tension measurements, and the critical micellization concentration values in AILs vary for their different cohesive energy. The micellar and lamellar lyotropic liquid crystal phases emerge with the increase of C16mimBr concentrations. The structure and properties of aggregates were determined using small angle X-ray scattering, polarized optical microscopy, rheology and differential scanning calorimetry. The anion effects of AILs on the phase behaviours and structure and properties of aggregates were analysed and discussed. The lamellar lyotropic liquid crystals have shown good conductivity, as confirmed by electrochemical impedance spectroscopy characterization. Our results enhance the understanding of the structure effect of ILs as self-assembly media and contribute to the design of tailorable solvents.
研究领域:
材料科学
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物理化学
·
胶体与界面科学
✓ 已验证
DOI
高影响因子
Chemistry-An Asian Journal
·
2016
·Vol. 11
·期 10
·1555-1564
·
IF 4.592
Cheng-Feng Du,Nan-Nan Shen,Jian-Rong Li,Min-Ting Hao,Zi Wang,Xiao-Ying Huang
Graphical MAC it happen : Presented is a study of the synergistic structure-directing effect of metal–amine complexes (MACs) with different chelating polyamine ligands and imidazolium-based ionic liquid (IL) cations. For the first time, a layered selenidostannate with an asymmetric eight-membered ring, an organic-decorated layered selenidostannate, and a 3D selenidostannate with both the MAC and IL cations as structure-directing agents and counterions are obtained. en=ethylenediamine, teta=triethylenetetramine, tepa=tetraethylenepentamine, 1,2-pda=1,2-diaminopropane. Presented are the ionothermal syntheses, characterizations, and properties of a series of two- and three-dimensional selenidostannate compounds synergistically directed by metal–amine complex (MAC) cations and ionic liquids (ILs) of [Bmmim]Cl (Bmmim=1-butyl-2,3-dimethylimidazolium). Four selenidostannates, namely, 2D-(Bmmim) 3 [Ni(en) 3 ] 2 [Sn 9 Se 21 ]Cl ( 1 , en=ethylenediamine), 2D-(Bmmim) 8 [Ni 2 (teta) 2 (μ-teta)]Sn 18 Se 42 ( 2 , teta=triethylenetetramine), 2D-(Bmmim) 4 [Ni(tepa)Cl] 2 [Ni(tepa)Sn 12 Se 28 ] ( 3 , tepa=tetraethylenepentamine), and 3D-(Bmmim) 2 [Ni(1,2-pda) 3 ]Sn 8 Se 18 ( 4 , 1,2-pda=1,2-diaminopropane), were obtained. Single-crystal X-ray diffraction analyses revealed that compounds 1 and 2 possess a lamellar anionic [Sn 3 Se 7 ] n 2 n − structure comprising distinct eight-membered ring units, whereas 3 features a MAC-decorated anionic [Ni(tepa)Sn 12 Se 28 ] n 6 n − layered structure. In contrast to 1 – 3 , compound 4 exhibits a 3D open framework of anionic [Sn 4 Se 9 ] n 2 n − . The structural variation from 1 to 4 clearly indicates that on the basis of the synergistic structure-directing ability of the MACs and ILs, variation of the organic polyamine ligand has a significant impact on the formation of selenidostannates.
研究领域:
材料科学
·
无机化学
✓ 已验证
DOI
PubMed
高影响因子
CRYSTAL GROWTH & DESIGN
·
2017
·
IF 4.055
Kaisheng Yao,Zhiyong Li,Xinying Li,Weiwei Lu,Airong Xu,Hucheng Zhang,Jianji Wang
The design of green and ingenious strategies for the fabrication of anisotropic nanoparticles and their assembly is particularly important in the advancement of nanoscience and nanotechnology but still remains an enormous challenge. In this work, the Ag films, with variously shaped particles as building blocks, were successfully prepared at the interface of different ionic liquids and water (ILs–H2O) under ambient conditions only by using ILs with different cationic structures. The as-prepared Ag films with different morphologies were characterized and analyzed by scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, and X-ray powder diffraction. The possible growth mechanisms were also suggested for the formation of differently morphological Ag films at the ILs–H2O interface. The as-obtained Ag films could be directly applied to perform surface-enhanced Raman scattering (SERS) studies. It was found that the nanobelt-contructed Ag films prepared at the interface of methyltrioctylammonium bis(trifluoromethylsulfonyl)imide ([N8881][Tf2N]) and water exhibited striking SERS sensitivities and good reproducibility.
研究领域:
材料科学
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF SOLID STATE ELECTROCHEMISTRY
·
2016
·Vol. 21
·期 2
·469-476
·
IF 2.327
Li Min,Gao Bingliang,Liu Chengyuan,Chen Wenting,Wang Zhaowen,Shi Zhongning,Hu Xianwei
AlCl 3 /amide (acetamide, propionamide, butyramide) ionic liquids were used as the electrolytes to study the electrodeposition behavior of aluminum on a tungsten electrode. Cyclic voltammograms on the tungsten electrode indicate that Al(III) ions can be reduced to aluminum only within the molar ratio range of 1.1 to 1.5 and the reduction potentials of Al(III) ions strongly depend on the molar ratio of AlCl 3 /amide. Raman spectra results reveal that the electroactive specie of AlCl 3 /amide ionic liquids is Al 2 Cl 7
− . Aluminum coatings were prepared at −0.25 V (vs. Al/Al 3+ ) and at 313 K in AlCl 3 /amide ionic liquids with the molar ratio of 1.3. The SEM and cross-sectional SEM images show that all the obtained aluminum films are silver-colored, thick, and adherent. The EDS and XRD analysis confirm that the obtained deposits are pure aluminum. The present results can provide a new route for aluminum electrodeposition under ambient conditions.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
ACS Sustainable Chemistry & Engineering
·
2019
·
IF 6.97
Xiong Zhang,Haowei Li,Xuan Li,Yong Liu,Xuehui Li,Jianyu Guan,Jinxing Long
The isomerization of glucose to fructose is a crucial step in the formation of high-value biochemicals from renewable cellulosic biomass. In this work, we have demonstrated a novel and efficient strategy for the aqueous isomerization of glucose catalyzed with basic ionic liquids. At 80 °C and 30 min, a fructose selectivity and yield of 73.8% and 36.8%, respectively, are obtained in the presence of tetrabutyl ammonium proline ([N4,4,4,4]Pro). Both of these values are notably larger than those obtained in numerous other technologies, making this technique a significant step toward selective generation of fructose. Further investigation reveals that the isomerization performance of glucose is influenced by the structure and hydrophobicity of the ionic liquids, where the latter enhances glucose isomerization via the formation of a microreactor. Moreover, this process exhibits a low activation energy of 34.4 kJ mol–1 with the [N4,4,4,4]Pro ionic liquid, correlating well with the high activity of this catalytic system. In addition, this IL catalyst shows good reusability as demonstrated by the retention of satisfactory performance after four consecutive runs. Based upon the above results, we have proposed a plausible catalytic mechanism, which can be further confirmed by DFT calculations and isotopic labeling studies.
研究领域:
生物化学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
·
2019
·
IF 4.561
Dongren Cai,Nisakorn Saengprachum,Zhipeng Lin,Ting Qiu
In this study, a molecular simulation (Gaussian03) was used to analyze the chemical structure of 4-dimethylaminopyridine (DMAP) to investigate its use for the synthesis of ionic liquids (ILs). Based on DMAP, a series of new ILs was prepared and characterized by fourier transform infrared spectroscopy (FT-IR), 1 H nuclear magnetic resonance ( 1 H-NMR), thermogravimetric analysis (TGA), and differential scanning calorimeter (DSC). The density data of the studied ILs were measured from 328.15 K to 358.15 K, p = 0.101 MPa. It is shown that density decreases with an increase in the temperature and the alkyl chain length of cations. And density is also affected by the anion type. Furthermore, the volume of ions, NBO charges, and the interactions of anions and cations were calculated by Gaussian03 to explain the obtained density results. The second-order polynomial equation was adopted to correlate the relationship of density and temperature. Then, an isobaric thermal expansion coefficient , molecular volume, and lattice potential energy were obtained from the density data. Viscosity was determined from 323.15 K to 368.15 K, p = 0.101 MPa. It is determined that the viscosity of ILs decreases with an increase in the temperature but increases with an increase in the alkyl chain length of cations. The temperature dependence of viscosity was described by the Vogel-Fulcher-Tamman (VFT) model, and the activation energy of viscous flow ( E η ) was obtained. Furthermore, the decomposition temperature ( T d ), glass transition temperature ( T g ), and melting temperature ( T m ) of ILs were obtained from the results of TGA and DSC.
研究领域:
化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2022
·
IF 7.392
Qingkai Zheng,Muhammad Chhattal,Changning Bai,Zhiwen Zheng,Dan Qiao,Zhenbin Gong,Junyan Zhang
Polytetrafluoroethylene (PTFE) is in the limelight due to its self-lubricating properties and outstanding corrosion resistance. Nevertheless, it suffers from severe adhesive and abrasive wear, resulting in barriers to the achievement of robust superlubricity and reliability of moving parts. Herein, two green protic ionic liquids (ILs) are synthesized using alkyl amine and carboxylic acids with long molecular chains, which are applied in PTFE/steel tribo-pair, showing a robust superlubricity under high contact pressure. Compared with conventional lubricating oils (PAO8, PAO10 and PEG400), as-prepared ILs show the lowest coefficients of friction less than 0.008, and the lowest wear volume of PTFE with the adhesive and abrasive wear of PTFE significantly inhibited. The excellent lubricating performance attributes to the thick and dense Stern layer as well as the formation of tribo-chemical film. This work, for the first time, achieves superlubricity on soft material substrates and guides the lubricants design for PTFE tribological applications.
研究领域:
材料科学
·
摩擦学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF PHYSICAL CHEMISTRY B
·
2023
·
IF 3.3
Chengyu He,Tie Liu,Peng Miao,Shuang Yuan,Jun Wang,Qiang Wang
Here, we demonstrate that high magnetic fields alter the wettability of water and ionic solutions on the single-crystal α-Al2O3. We investigated the relationship between the substrate crystal orientation, material magnetism, liquid conductivity, and the surface contact angle. Applying high magnetic fields decreased the water contact angles on all of the surface orientations studied, and the reduction was larger for more magnetic substrates. For ionic solutions, high magnetic fields increased the contact angle on the (0001) α-Al2O3 surface but decreased the contact angles on the (112̅0), (101̅0), and (011̅2) surfaces. We attribute these orientation-dependent ionic solution responses to competition between the field-induced sample magnetization energy and the Lorentz force acting on the ionic solution. Overall, this work provides new magnetic-field-based strategies for changing the wettability and provides guidelines for fabricating novel microfluidic systems or biointerfaces with in situ magnetic control.
研究领域:
材料科学
·
物理学
·
化学
·
微流控技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
WATER AIR AND SOIL POLLUTION
·
2023
·Vol. 234
·期 7
·1-9
·
IF 2.9
Shi Zhimeng,Liu Yuchen,Wang Xiaowen,Du Kehui,Tian Hongzhe
Five choline ionic liquids were selected to evaluate their toxicity to green alga ( Chlorella vulgaris ) and Daphnia magna . Their influence on chlorophyll content, respiration rate, antioxidase activity, and malondialdehyde content of Chlorella vulgaris and the acute and chronic toxicity of Daphnia magna were investigated. The studied ionic liquids slightly inhibited the algal growth with the median effective concentrations (EC 50 ) > 1900 mg/L. Chlorophyll contents, respiration rate, and protein contents of the alga after 96 h of exposure decreased with the higher concentrations of the ionic liquids, while superoxide dismutase and catalase activity and malondialdehyde content increased firstly and then decreased. The acute toxicity of Daphnia magna after 48 h of exposure (indicated by the median effective concentrations, EC 50 ) was 200.44 and 184.50 mg/L for choline acetate and choline D-lactate, respectively, which was above the toxicity of other ionic liquids. The studied ionic liquids presented low toxicity to Chlorella vulgaris and Daphnia magna .
研究领域:
生态毒理学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2023
·
IF 8.6
Jiming Yang,Kai Luo,Xingmei Lu,Wei He,Shuangfei Zhao,Zheng Fang,Yirong Feng,Ning Zhu,Kai Guo
Polyhydroxy compounds such as sugar alcohols /derivatives are high value chemicals with application potential in medicine, materials and other fields. Researches on preparation and selective extraction of polyhydroxy compounds have attracted wide attention in the world. However, the selective extraction of polyhydroxy compounds is still a major challenge. In this paper, hydrophobic ionic liquids (ILs) 1-butyl-3-methylimidazole bis(trifluoromethanesulfon)imide salt ([Bmim][Ntf 2 ]), 1-ethyl-3-methylimidazole bis(trifluoromethanesulfon)imide salt ([Emim][Ntf 2 ]) and 1-allyl-3-methylimidazole bis(trifluoromethanesulfon)imide salt ([Amim][Ntf 2 ])) were used for the dissolution and selective extraction of polyhydroxy compounds. In addition, the interaction between ionic liquids and polyhydroxy compounds was characterized and analyzed by NMR and contact angle analysis. The partition coefficients of polyhydroxy compounds in water and hydrophobic ionic liquids were also investigated. It was shown that among the ILs used, the solubility of polyhydroxy compounds fluctuated strongly (from 0 wt% to 19.50 wt%), and the solubility in [Amim][Ntf 2 ] was the highest. These hydrophobic ionic liquids showed strong selective extraction ability when fractionating mixtures composed of sugar alcohols and their dehydrated derivatives (1:1, w / w). The results showed that the purities of isosorbide and isomannide separated were more than 99.60 wt% and 99.99 wt% respectively. Polyhydroxy compounds dissolved in hydrophobic ionic liquids could be directly extracted by water without chemical modification. The regeneration rate of ionic liquids reached 93.22%−97.04%. The NMR characterization of the regenerated ionic liquid showed that water could fully extract polyhydroxy compounds dissolved in the ionic liquids and the structure of the regenerated ionic liquid did not change. It was promising to construct a green and efficient method for fractionating such polyhydroxy compounds based on hydrophobic ionic liquids, and it is suggested to further strengthen the research in this field.
研究领域:
化学工程
·
材料科学
·
绿色化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）