International Journal of Chemical Engineering
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2016
·
IF 0
Lili Li,Yupin Guo,Chunchao Zhao,Mengxia Wei,Junling Liu,Yuangang Zu,Fei Wang,Lei Yang
In order to hydrolyze geniposide and extract geniposidic acid, a novel microwave irradiation heating method for simultaneous hydrolysis and extraction for preparation of geniposidic acid from Eucommia ulmoides bark using basic imidazolide ionic liquid was developed in this work. Basic ionic liquid paired by imidazolide anion and 1-hexyl-3-methylimidazolium cation ([C6mim]Im) was used as a dual hydrolysis catalyst and extraction solvent in the proposed approach. The optimal concentration of [C6mim]Im was 0.4 mol/L. And the independent parameters optimized by Box-Behnken design (BBD) based on single-factor tests were as follows: microwave irradiation time of 20 min at power of 415 W and liquid-solid ratio of 15 mL/g. Yield of geniposidic acid was increased to μmol/g. DM130 macroporous resin, after reaction, was selected to separate geniposidic acid from hydrolysate. The plant materials with different treatment were analyzed by scanning electron microscopy (SEM) and thermogravimetric analysis (TG). The analysis of SEM and TG further indicated that IMSHE is an efficient preparation method for geniposidic acid. It is reasonable to assume that the method and the dual hydrolysis catalyst and extraction solvent would offer an alternative for the preparation of some other kinds of bioactive substances from plant materials.
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Materials Research Express
·
2016
·Vol. 3
·期 9
·095020
·
IF 0.968
Congyue Wang,Chunfeng Wang,Dong Sun,Aoqi Li,Yujuan Chen,Kelei Zhuo
Heteroatom doped carbon dots (CDs) possess many unique properties and have attracted increasing attention. The precursor is vital for the preparation of highly fluorescent heteroatom doped CDs. Herein, 1, 3-bis(carboxymethyl)imidazolium chloride ([Im(AH)2]Cl, a COOH-functional ionic liquid) and aminoethylethanolamine (AEEA) were firstly used as precursors to prepare nitrogen-doped carbon dots (N-CDs) by a simple one-step pyrolysis approach. The effects of reaction time, temperature, and mass ratio of precursors on the quantum yield (QY) of N-CDs were investigated. The prepared N-CDs are spherical morphology with an average diameter of 2.4 nm, and have blue fluorescence with a QY of 23.2% and excitation-dependent emission behavior. They also possess good water solubility and fluorescent stability. In addition, based on the obtained N-CDs, a sensing method of free chlorine detection in acidic water system was introduced. The proposed method has good sensitivity and selectivity to free chlorine, and exhibits a nice linear response in the concentration range from 0.2 to 22 μM with a detection limit of 0.15 μM. Furthermore, this sensing method was successfully applied to detect free chlorine of tap water with satisfactory recovery (97%–103%), suggesting it has the potential application in water quality monitoring.
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高影响因子
RSC Advances
·
2016
·Vol. 6
·期 35
·29172-29181
·
IF 3.289
Xuzhao Yang,Hao Song,Jun Wang,Wenyuan Zou
A novel asymmetrical gemini ionic liquid, 1-(1-methypiperidinium-1-yl)hexane-(1-pyridinium)bi[bis(trifluoromethanesulfonyl)imide] ([MPiC6Py][NTf2]2) was synthesized and characterized by 1H NMR, 13C NMR and IR. Elemental analysis was performed on a Vario EL III instrument. Densities, viscosities and refractive indexes were measured for the binary mixture of [MPiC6Py][NTf2]2 with acetonitrile over the entire range of mole fractions at temperatures from T = (293.15 to 323.15) K under the atmospheric pressure of 0.1 MPa. Using the basic experimental data, the excess molar volumes (VEm), the viscosity deviations (Δη) and the refractive index deviations (ΔnD) for the binary systems were calculated and correlated to the Redlich–Kister polynomial to estimate coefficients and the standard deviation between the experimental and calculated values. The negative values of VEm and Δη result from strong self-association and weak hydrogen bonding interactions between the molecules of [MPiC6Py][NTf2]2 and acetonitrile. The values of ΔnD are all positive for the binary mixtures and increase with increasing temperature. The enthalpy, entropy and excess Gibbs energy of activation of the viscous flow of the binary mixtures also have been determined. The values of molar refraction and polarizability indicate that the dominant interactions between [MPiC6Py][NTf2]2 and acetonitrile are dipole–dipole molecular interactions. The obtained results are hoped to provide helpful information for the fundamental physicochemical properties of asymmetrical gemini ionic liquids and their further industrial applications.
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高影响因子
ANALYTICAL LETTERS
·
2016
·
IF 1.088
Xingxiu Qin,Xiashi Zhu
Novel solid phase extraction using an α-picoline ionic liquid-β-cyclodextrin-cross-linked polymer is reported with high-performance liquid chromatography for the determination of allura red. The linear dynamic range, limit of detection, limit of quantitation, and relative standard deviation values were 5.0–2.5 × 104 µg L−1, 0.35 µg L−1, 1.17 µg L−1, and 0.47%, respectively. The preconcentration factor of method was approximately fourteen, and the α-picoline based ionic liquid-β-cyclodextrin polymer may be used for up to thirteen times. The mechanism of adsorption was investigated by kinetic modeling and the inclusion interaction of the ionic liquid-β-cyclodextrin-cross-linked polymer with allura red was characterized. This method was employed for the determination of allura red in food with satisfactory results.
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高影响因子
ELECTROCHIMICA ACTA
·
2017
·
IF 4.798
Nanjun Chen,Yang Liu,Chuan Long,Rui Li,Fanghui Wang,Hong Zhu
We present an effective method to improve the comprehensive performance of anion exchange membranes (AEMs) by fixing ionic-liquid-coated silica in trimethylamine functionalized poly(2,6-dimethyl-1,4-phenylene oxide). The ionic liquid (IL) is locked on the surface of silica by chemical bonds to stabilize the IL in AEMs. Crosslinked structure between the modified silica and polymer backbone is designed to improve the performance of the AEMs. As expected, the hydroxide conductivity, mechanical properties, dimensional stability, and chemical stability of the quaternized poly(2,6-dimethyl-1,4-phenylene oxide)/modified silica composite membranes (designated as QAPPO/IL-SiO 2 ) are improved by the introduction of the modified silica. The QAPPO/8% IL-SiO 2 composite membrane exhibits the highest hydroxide conductivity of 70.2 mS cm −1 at 80 °C and the lowest activation energy of 12.1 kJ mol −1 . Besides, the QAPPO/8% IL-SiO 2 composite membrane show a higher dimensional stability after hot pressing than the pristine membrane. The loss-resistance test of IL in the QAPPO/8% IL-SiO 2 composite membrane shows a negligible loss rate for the IL in the membrane. The QAPPO/8% IL-SiO 2 composite membrane achieves a maximum power density of 145.40 mW cm −2 at a current density of 340.76 mA cm −2 . Therefore, the QAPPO/IL-SiO 2 composite membranes are promising AEM materials for fuel cells.
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高影响因子
RSC Advances
·
2014
·Vol. 4
·期 81
·43029-43038
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IF 3.708
Heping Gao,Yinxian Peng,Jianming Pan,Jun Zeng,Changhua Song,Yunlei Zhang,Yongsheng Yan,Weidong Shi
Stable water-in-oil (W/O) Pickering high internal phase emulsions (HIPEs) with an internal phase volume fraction of 84.8% were first stabilized by both the hydrophobic silica nanoparticles and span 80. Then, based on the obtained Pickering HIPEs, several macroporous polymerized solid acid (PDVB-SS-X-SO3H, X = 0, 0.2, 0.6) were prepared by polymerizing divinyl benzene (DVB) and sodium p-styrenesulfonate (SS), and were subsequently combined with sulfonation in H2SO4. All the as-prepared PDVB-SS-X-SO3H possessed open-cell structure, interconnecting pores and strong acidity, and were adopted as catalysts to convert cellulose into 5-hydroxymethylfurfural (HMF) in the presence of [Emim]Cl-mediated solvents. The results showed a maximum yield of 29.6% for PDVB-SS-0.2-SO3H, 12.9% for PDVB-SS-0-SO3H and 15.5% for PDVB-SS-0.6-SO3H under the same condition within 2.0 h at 120 °C, suggesting that the pore sizes and strong acidic sites played a key role in cellulose conversion. PDVB-SS-X-SO3H can be very easily recycled at least four times without a significant loss of activity. This research opens up a new method to synthesize porous solid acid catalyst materials through Pickering HIPEs templates.
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高影响因子
ELECTROCHIMICA ACTA
·
2013
·
IF 3.777
Rui Li,Changxian Liu,Ming Ma,Zhengguo Wang,Guoqing Zhan,Buhai Li,Xian Wang,Huaifang Fang,Huijuan Zhang,Chunya Li
1,3-Di(4-amino-1-pyridinium)propane tetrafluoroborate (DAPPT) ionic liquid was successfully synthesized, and was used as a modifier to functionalize graphene nanosheets through covalent binding of amino groups and epoxy groups in an alkaline solution. The as-prepared graphene-DAPPT nanosheets (Gr-DAPPT) were confirmed with transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV/vis and FTIR spectroscopy. A biocompatible platform based on Gr-DAPPT was constructed for the immobilization of hemoglobin (Hb) through a cross-linking step with chitosan and glutaraldehyde. The direct electron transfer and bioelectrocatalytic reaction of Hb immobilized on Gr-DAPPT surface were achieved. A pair of reversible redox peaks of hemoglobin was observed, and bioelectrocatalytic activity toward the reduction of H 2 O 2 was also demonstrated, displaying a potential application for the fabrication of novel biosensors to sense H 2 O 2 . Such results indicated that Gr-DAPPT based interface would be a promising platform for biomacromolecular immobilization and biosensor preparation.
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高影响因子
Soft Matter
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2012
·Vol. 8
·期 46
·11644-11653
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IF 4.39
Zhangwei Wang,Hengjie Lai,Peiyi Wu
The assembly properties, thermal phase behavior and microdynamics of poly(NIPAM-b-BVImBr), poly(N-isopropylacrylamide)-b-poly(1-butyl-3-vinylimidazolium bromide), in aqueous solution are investigated by dynamic light scattering (DLS), turbidity measurements and FTIR spectroscopy in combination with two-dimensional correlation spectroscopy (2Dcos) and the perturbation correlation moving window (PCMW) technique. In particular, the influence of the introduction of the poly(BVImBr) segment on the solution properties of the block copolymer has attracted our attention: a core–shell micelle structure forms, consisting of a relatively hydrophobic core of poly(BVImBr) and a hydrophilic shell of PNIPAM; the phase transition temperature increases, due to one more step in the dehydration process originating from the alkyl side chains of the poly(1-butyl-3-vinylimidazolium bromide) (PIL) segment; what's more, a stronger hysteresis during the heating–cooling cycle, closely related to the recovery process, is observed. It reveals that the hydrogen bonds of CO⋯D–N among the micelles formed during heating are harder to remove, thus, the reconstruction of the CO⋯D–O–D hydrogen bonding and the recovery hydration process for the C–H groups during cooling are prevented due to the compact and regular micelle structure. More interestingly, the CO groups interact with the N–D groups at room temperature because of the existence of the micelle structure, which is regarded as intra-micelle hydrogen bonding; above the LCST, hydrogen bonds of the CO⋯D–N among the aggregated micelles called inter-micelle hydrogen bonding occur.
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高影响因子
ANALYST
·
2014
·Vol. 139
·期 8
·1938-1944
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IF 3.906
Xiaoji Cao,Lingxiao Shen,Xuemin Ye,Feifei Zhang,Jiaoyu Chen,Weimin Mo
An ultrasound-assisted magnetic solid-phase extraction procedure with the [C7MIM][PF6] ionic liquid-coated Fe3O4-grafted graphene nanocomposite as the magnetic adsorbent has been developed for the determination of five nitrobenzene compounds (NBs) in environmental water samples, in combination with high performance liquid chromatography-photodiode array detector (HPLC-PDA). Several significant factors that affect the extraction efficiency, such as the types of magnetic nanoparticle and ionic liquid, the volume of ionic liquid and the amount of magnetic nanoparticles, extraction time, ionic strength, and solution pH, were investigated. With the assistance of ultrasound, adsorbing nitrobenzene compounds by ionic liquid and self-aggregating ionic liquid onto the surface of the Fe3O4-grafted graphene proceeded synchronously, which made the extraction achieved the maximum within 20 min using only 144 μL [C7MIM][PF6] and 3 mg Fe3O4-grafted graphene. Under the optimized conditions, satisfactory linearities were obtained for all NBs with correlation coefficients larger than 0.9990. The mean recoveries at two spiked levels ranged from 80.35 to 102.77%. Attributed to the convenient magnetic separation, the Fe3O4-grafted graphene could be recycled many times. The proposed method was demonstrated to be feasible, simple, solvent-saving and easy to operate for the trace analysis of NBs in environmental water samples.
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PubMed
高影响因子
JOURNAL OF THE BRAZILIAN CHEMICAL SOCIETY
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2013
·Vol. 24
·期 6
·1034-1040
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IF 1.283
Yu Chen,Zhang Sanbing,Zhang Jiaheng,Li Songqing,Zhou Wenfeng,Gao Haixiang,Lu Runhua
An in situ ionic liquid dispersive liquid-liquid microextraction (IL-DLLME) method was developed as a new approach for the detection of four pyrethroid pesticides in environmental water samples. The method is fast, simple, accurate and environmentally friendly. The hydrophobic ionic liquid, [C8MIM]-NTf2, formed by the water-soluble ionic liquid [C8MIM]Cl and the ion exchange reagent LiNTf2 was used as the extraction solvent. The experimental parameters affecting the extraction efficiency, including the amount of the IL, the extraction and the centrifugation times and the salt concentration were investigated and optimized using an orthogonal array design (OAD). A suitable molar ratio of LiNTf2 to [C8MIM]Cl on the recoveries of analytes was determined after OAD optimization. The method showed a good linear response in the range of 0.5 to 500 µg L-1 with correlation coefficients (R²) above 0.9998. The relative standard deviation (RSD) varied from 0.6 to 1.9%. The enrichment factor, the limit of detection and recovery ranged from 134 to 153, 0.02 to 0.18 µg L-1 and 89.7 to 95.6%, respectively. For water samples, the RSD ranged from 0.02 to 2.34% and the recovery ranges from 91.4 to 99.9%.
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高影响因子
ANALYTICA CHIMICA ACTA
·
2015
·
IF 4.513
Datong Wu,Pengfei Cai,Zhihao Tao,Yuanjiang Pan
In this study, a novel task-specific ionic liquid functionalized gold nanoparticle (TSIL-GNP) was successfully prepared and applied in the recognition of amino acids . Particularly, the surface of GNP was modified with the ionic liquid containing carbamido and ester group via thiol, which was characterized by Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). The stability of this material in aqueous solution improves apparently and can remain unchanged for more than three months. The effect of pH was also discussed in this study. Attractive ionic interaction would effectively weaken intensity of the covalent coupling between the metal ion and the functional groups of amino acids. Thus, TSIL-GNP was successfully applied to recognizing serine , aspartic acid , lysine, arginine, and histidine in the presence of Cu 2+ through distinctive color changes. Suspension would be generated once a spot of cysteine was added into the GNPs solution. Results indicated that it had a good linear relationship between extinction coefficients and concentration of amino acids in a wide range of 10 −3 –10 −6 M. Moreover, the proposed strategy was successfully used to analyze the histidine in urinary samples. In brief, TSIL-GNP is a suitable substrate for discrimination of five amino acids in a rapid and simple way without sophisticated instruments.
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PubMed
高影响因子
RSC Advances
·
2015
·Vol. 5
·期 113
·92932-92939
·
IF 3.84
Xiaojiao Wang,Chuannan Luo,Leilei Li,Huimin Duan
An imprinted electrochemical sensor based on graphene oxide/carboxylated multiwalled carbon nanotube/ionic liquid/gold nanoparticles/molecularly imprinted polymers (GO/CCNTs/IL/AuNPs/MIPs) has proved highly ultrasensitive and selective in the analysis of vanillin in spiked water samples. The GO/CCNTs/IL/AuNPs composite was utilized to improve the electrochemical response and sensitivity of the sensor. The molecularly imprinted polymer membrane was prepared by electropolymerization and could specifically determine vanillin. Under optimized conditions, the prepared molecular imprinting electrode material showed fast rebinding dynamics, and was successfully applied to vanillin detection with a wide linearity range from 1.00 × 10−8 to 2.50 × 10−6 mol L−1 and a detection limit of 6.23 × 10−10 mol L−1. The proposed imprinted electrochemical sensor also exhibited high repeatability (relative standard deviation of 3.16%) and stability (3.8%) for the analysis of real samples.
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高影响因子
危险品化学品经营许可证（带存储）