INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2014
·
IF 2.235
Nan Li,Fang Wang,Zhiqing Zhang,Huihui Nie,Chengcheng Ren,Mei Cui
Polymeric 1-vinyl-3-ethylimidazolium tetrafluoroborate ionic liquids modified microspheres of silica gel were prepared by free radical polymerization in toluene. Characterization with Fourier transform infrared (FTIR), elemental analysis, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), gel permeation chromatography (GPC), thermogravimetric analysis (TGA), and 13C, 29Si magic angle spinning (MAS) nuclear magnetic resonance (NMR) demonstrated that 1-vinyl-3-ethylimidazolium tetrafluoroborate had successfully loaded on the surface of silica gel and formed a stable polymer coating. Furthermore, to detect the potential desulfurization performance, a series of experiments of model fuel desulfurization with polymeric ionic liquid modified silica gel had been carried out. The desulfurization efficiency of modified silica gel was investigated by removing 2-methylthiophene, benzothiophene, and dibenzothiophene from model fuel (n-heptane/2-methylthiophene, benzothiophene, and dibenzothiophene) under tested conditions. It was shown that the modified silica gel exhibited remarkable desulfurization capacity for aromatic S-containing compounds and the sulfur removal selectivity followed the order of 2-methylthiophene < benzothiophene < dibenzothiophene due to the different density aromatic π-electrons.
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CARBON
·
2014
·
IF 6.16
Deli Xiao,Danhua Yuan,Hua He,Chuong Pham-Huy,Hao Dai,Cuixia Wang,Chan Zhang
A novel mixed hemimicelles solid phase extraction (SPE) based on magnetic carbon nanotubes (MCNTs) and ionic liquid (IL) is developed for the simultaneous extraction and determination of trace flavonoids in spiked human urine. In this novel SPE, the formation of C 16 mimBr with mixed hemimicelles on the surface of MCNTs@SiO 2 nanoparticles (NPs) causes retention of analytes by strong hydrophobic, π–π and electrostatic interactions . This SPE technique combines the advantages of mixed hemimicelles and MCNTs. In order to establish the guidelines for the preparation of mixed hemimicelles on composite materials, different main factors affecting the preconcentration of analytes, such as material type , amount of surfactant , pH of solution, ionic strength , extraction time, desorption condition and regeneration property, were investigated and optimized. Under the selected conditions, the accuracy of the method was evaluated by recovery measurements on spiked samples, and good recoveries with low relative standard deviations from 3.5% to 4.9% were achieved. No interferences were caused by endogenous compounds in human urine. For our knowledge, this is the first development of a mixed hemimicelles SPE based on MCNTs and IL for the extraction of trace analytes in complex biological samples.
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BIOPROCESS AND BIOSYSTEMS ENGINEERING
·
2014
·Vol. 37
·期 8
·1617-1626
·
IF 1.823
Hu Yi,Yang Jiao,Jia Ru,Ding Yan,Li Shuang,Huang He
Chemical modification of lysine residues in Candida rugosa lipase (CRL) was carried out using five different functional ionic liquids, and about 15.4–25.0 % of the primary amino groups of lysine were modified. Enzymatic properties of the native and modified CRLs were investigated in olive oil hydrolysis reaction. Improved thermal stability, catalytic activity in organic solvents, and adaptability to temperature and pH changes were achieved compared with the native enzyme. CRL modified by [choline][H 2 PO 4 ] showed the best results, bearing a maximum improvement of 16.7 % in terms of relative activity, 5.2-fold increase in thermostability (after incubation at 45 °C for 5 h), and 2.3-fold increase in activity in strong polar organic solvent (80 % dimethyl sulfoxide) compared with the native enzyme. The results of ultraviolet, circular dichroism and fluorescence spectroscopy suggested that the change of the secondary and tertiary structures of CRL caused by the chemical modification resulted in the enhancement of enzymatic performance. The modification of CRL with functional ionic liquids was proved to be a novel and efficient method for improving the enzymatic properties of CRL.
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PubMed
高影响因子
MOLECULES
·
2015
·Vol. 20
·期 5
·7683-7699
·
IF 2.416
Ying Zhou,Datong Wu,Pengfei Cai,Guifang Cheng,Chaobiao Huang,Yuanjiang Pan
A microwave-assisted extraction approach based on ionic liquids of different chain lengths was successfully applied to the extraction of ten flavonoid glycosides from the flowering heads ofChrysanthemum morifoliumRamat. The pretreated sample was quantified by HPLC-ESI-MSn. The main components were identified as flavonoid glycosides, including three luteolin glycosides, three apigenin glycosides, three kaempferide glycosides, and one acacetin glycoside according to the characteristics of the corresponding CID mass spectrometric patterns. Eight ionic liquids from the imidazolium family with different chain lengths, namely, 1-alkyl-3-methylimidazolium bromide, [Cnmim]Br, (n = 2–16) were studied as extraction medium in water. Results indicated that alkyl chain length had an irregular impact on the extraction efficiency. Moreover, the best extraction efficiency was achieved by 1-dodecyl-3-methylimidazolium bromide aqueous solution ([C12mim]Br). Besides the alkyl chain length of the cations, other factors influencing extraction efficiency were systematically investigated, including concentration of the IL solutions, extraction time, matrix-to-solvent ratio and irradiation power.Keywords:ionic liquids;flavonoid glycosides;microwave-assisted extraction;Chrysanthemum morifoliumRamat
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高影响因子
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
·
2015
·Vol. 16
·期 12
·28146-28155
·
IF 2.862
Qing You,Yan Zhang,Huan Wang,Hongfu Fan,Jianping Guo,Ming Li
Wormlike micelles are typically formed by mixing cationic and anionic surfactants because of attractive interactions in oppositely charged head-groups. The structural transitions of wormlike micelles triggered by pH in ionic liquids composed ofN-alkyl-N-methylpyrrolidinium bromide-based ILs (ionic liquids) and anthranilic acid were investigated. These structures were found responsible for the variations in flow properties identified by rheology and dynamic light scattering, and account for the structures observed with cryogenic transmission electron microscopy (Cryo-TEM). High-viscosity, shear-thinning behavior, and Maxwell-type dynamic rheology shown by the system at certain pH values suggested that spherical micelles grow into entangled wormlike micelles. Light scattering profiles also supported the notion of pH-sensitive microstructural transitions in the solution. Cryo-TEM images confirmed the presence of spherical micelles in the low-viscosity sample and entangled wormlike micelles in the peak viscosity sample. Nuclear magnetic resonance spectroscopy analysis revealed that the pH sensitivity of ionic liquid systems originated from the pH-dependent binding ability of anthranilic acid to the cationic headgroup of ionic liquids.Keywords:pH-sensitive;wormlike micelles;rheology;morphological variation;formation mechanism
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高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2015
·
IF 2.752
Aili Wang,Li Chen,Fan Xu,Zongcheng Yan
Epoxidized soybean oil (ESBO)-based ionic liquid microemulsions are promising alternatives for petroleum-based lubricants. This study presents the phase behavior of these microemulsions through phase manifestation, and the areas of the single-phase domain were accordingly calculated to illustrate the phase-forming capacities of the designed microemulsions. Effects of ionic liquid anions and cations, surfactant and co-surfactant chain lengths on the phase behavior, and phase-forming capacities of ESBO-based ionic liquid microemulsions were investigated. Results showed that the phase-forming capacities of the ESBO-based ionic liquid microemulsions with different ionic liquid anions and cations showed the following sequence: Tf 2 N − -based > PF 6 − -based > BF 4 − -based, OMIM + -based > HMIM + -based > BMIM + -based > EMIM + -based. Given the presence of ionic liquid–ESBO amphiphilic balance in the designed systems, the ESBO–surfactant micelles achieved maximum solubilization capacity for 1-butyl-3-methyl-imidazolium tetrafluoroborate when the surfactant had approximately eight ethoxylated groups. In addition, ESBO-based microemulsion containing n -hexanol showed a higher phase-forming capacity than that containing n -butanol, and n -octanol caused a different phase behavior for the ESBO-based microemulsion because of its oilier nature than a co-surfactant.
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高影响因子
RSC Advances
·
2014
·Vol. 4
·期 43
·22520-22525
·
IF 3.708
Yong Liu,Yi-Tao Wang,Tao Liu,Duan-Jian Tao
SO3H-functionalized Brønsted acidic ionic liquids (BAILs) were synthesized and utilized as highly efficient catalysts for the production of fructone via the acetalization reaction of ethyl acetoacetate with ethylene glycol. In comparison with conventional H2SO4 and cation exchange resins, the BAILs N-(4-sulfonic acid) butyl triethylammonium hydrogensulfate ([BSEt3N][HSO4]) of strong acidities exhibited excellent catalytic activities. The effects of various parameters such as different BAILs, reaction temperature, catalyst dosage, and molar ratio of the reactants on the conversion of ethyl acetoacetate were investigated in detail. The experimental results indicated that the catalytic performance of BAILs were closely related to their Hammett acidities. Moreover, it was found that [BSEt3N][HSO4] could be also recovered easily and used repetitively six times without obvious decline in activity and quantity, showing great potential application in industry.
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高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2014
·Vol. 49
·期 14
·4919-4926
·
IF 2.305
Du Zhiping,Li Enze,Li Guojin,Cheng Fangqin,Wang Guoyong
Yolk–shell silica spheres consisting of a core and an outer shell were prepared by a one-step method using a new class of eco-friendly templates, trisiloxane-tailed surface active ionic liquids. The effects of pH, calcination, and template concentration were investigated in detail. Our results showed that yolk–shell silica spheres could be obtained only in alkaline conditions when using trisiloxane-tailed ionic liquids as templates. The particle diameter, core diameter, dimension of void space, and shell thickness, which we measured by transmission electron microscopy and nitrogen adsorption–desorption techniques, could be tuned by precisely varying the template concentration. The organosilicon component of the ionic liquid template contributes to the reaction during the formation of yolk–shell nanostructures, which leads to a firm silica sphere skeleton resulting in essentially identical morphology and void structure before and after calcination. This investigation provides a convenient approach to fabricate yolk–shell silica spheres, which may expand the application of organosilicon ionic liquids in the field of nanomaterials and could be expected to generate tailor-made yolk–shell silica with functionality in both the core and shell.
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ORGANIC & BIOMOLECULAR CHEMISTRY
·
2013
·Vol. 11
·期 41
·7192-7198
·
IF 3.568
Ru Jia,Yi Hu,Luo Liu,Ling Jiang,He Huang
Various imidazolium-functional ionic liquids (ILs) composed of different cations and anions were grafted onto Candida antarctica lipase B (CALB) through lysine coupling, and 4–6 of the 9 primary amino groups of the lysine residues were modified. The catalytic activity and stability were investigated in a p-nitrophenyl palmitate hydrolysis reaction. After modification, CALB was activated and achieved a high catalytic efficiency in the aqueous phase (e.g., [HOOCMMIm][Cl] modification showed a 1.5-fold increase in the catalytic efficiency). The thermostability and organic solvent tolerance were significantly increased with the ILs modification (e.g., [HOOCBMIm][Cl] owned kosmotropic cation and chaotropic anion modification showed a 7-fold thermostability increase at 70 °C, 1-fold increase in 50% aqueous dimethylformamide and 5-fold increase in 50% aqueous methanol). Conformation changes were confirmed by fluorescence spectroscopy, circular dichroism spectroscopy and attenuated total reflection Fourier transform infrared spectroscopy.
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高影响因子
ACS Sustainable Chemistry & Engineering
·
2015
·
IF 4.642
Yuehua Chen,Huiyong Wang,Yuanchao Pei,Jiao Ren,Jianji Wang
The recovery of rare-earth metals from waste materials is very important due to the risks associated with having a low supply of them in the future. In this work, hydrophobic 1-alkylcarboxylic acid-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ionic liquids, [(CH2)nCOOHmin][Tf2N] (n = 3, 5, 7), were synthesized and used to separate neodymium (III) from Fe(III) and samarium (III) from Co(II) in aqueous solutions. The factors affecting the solvent extraction process such as phase volume ratio, contact time, pH value of the aqueous phase, alkyl chain length of the ionic liquids, and temperature of the system were examined systematically. It was found that the maxmium extraction efficiency of the investigated metal ions was as high as 99%, and Sm(III) and Nd(III) could be selectively separated from Co(II) and Fe(III), with separation factors of 104–105, by simply modulation of the aqueous phase pH. After extraction, about 97% of the metal ions could be stripped from ionic liquid phase in a single stripping step by using dilute aqueous HCl or oxalic acid, and the ionic liquids would be recovered and reused in the next extraction process. These results indicate that the ionic liquids developed here are useful for the selective recovery of rare-earth metals from NdFeB and SmCo permanent magnets.
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JOURNAL OF CHEMICAL AND ENGINEERING DATA
·
2016
·
IF 1.835
Tian Tian,Xiaoling Hu,Ping Guan,Yimei Tang
N-Vinyl-3-alkylimidazolium tetrahalogenidoferrate(III) ([VRIM][FeX4], X4 = Cl3Br, Cl4) and N-vinyl-3-esterimidazolium tetrachloroferrate(III)([VEIM][FeCl4]) magnetic ionic liquids were synthesized. They were characterized by 1H NMR, Raman, electrospray ionization mass spectrometry, differential scanning calorimetry and thermogravimetric analysis. Through Gaussian09/B3LYP/LANL2DZ density functional theory, the interaction energies of ion pairs and dipole moment of [VRIM][FeX4] and [VEIM][FeCl4] were obtained. The relationships between the surface tensions and temperature, molecular structure, and interaction energies of ion pairs along with the relationships between the solubility and molecular structure, common solvents, and interaction energies of ion pairs were discussed systematically. The relationship between the surface tensions and solubility parameter for [VRIM][FeX4] was expressed by using a Hildebrand–Scoff equation. And the hydrophilic–lipophilic balance (HLB) values of [VRIM][FeX4] were obtained by a solubility parameter. The results showed that surface tension decreased linearly with temperature and decreased with the elongation of alkyl chain length on cation and the decrease of interaction energies of ion pairs; With decreasing dielectric constant of solvent, the solubility of the title magnetic ionic liquids increased first and then decreased; with the elongation of alkyl chain length, the interaction energies of ion pairs and HLB value decreased, and the solubility in polar solvents had a decreasing trend.
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COLLOID AND POLYMER SCIENCE
·
2017
·Vol. 295
·期 10
·1863-1871
·
IF 1.723
Zhang Zhiqing,Cui Mei,Wang Fang,Zhou Ting,Zhang Guodong,Wang Xiufeng
Ionic liquids (ILs) as environmental-friendly extractive solvents can remove aromatic heterocyclic sulfur compounds (S-compounds) from fuel oils, which due to their capacity for S-compounds (easy separation and higher selectivity). In this work, a series of polystyrene (PS)-supported polymeric ILs (PS-PILs or PS-6-PILs) with different alkyl side chain length were synthesized. Characterization with Fourier transform infrared (FTIR), nuclear magnetic resonance (NMR), elemental analysis, scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) demonstrated that IL monomers had been successfully loaded and polymerized on the surface of PS to form a thin polymer coating. The adsorptive desulfurization behavior of polystyrene-supported polymeric ILs was investigated by removing aromatic S-containing compound from model fuel (cyclohexane/thiophene, 2-methylthiophene, benzothiophene, and dibenzothiophene). Under the experimental conditions, the adsorption ability followed the order of PS < PS-PILs < PS-6-PILs. With the length of alkyl chain of imidazole ring increased, the desulfurization rate of thiophene was gradually increased, 2-methylthiophene was first increased and then decreased, benzothiophene and dibenzothiophene were slightly decreased. These trends were due to the different steric effect and aromatic π-electron density of ILs with different alkyl side chain length.
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危险品化学品经营许可证（带存储）