MICROCHEMICAL JOURNAL
·
2020
·
IF 3.594
Ying Ji,Yuan Li,Binbin Ren,Xinsheng Liu,Yonghong Li,Jeffrey Soar
The analysis of quercetin (Qu) is of great significance owing to its multiple biomedical effects. In this work, a nitrogen-doped graphene-ionic liquid-glassy carbon microsphere paste electrode (N-GE/GCILE) was constructed for the determination of Qu. Cyclic voltammetry (CV) and square wave voltammetry (SWV) were employed to investigate the electrochemical behavior of Qu. In comparison with unmodified glassy carbon microsphere paste electrode, the modified electrode exhibited better electrocatalytic activity towards Qu. The influencing conditions on sensitivity such as the amount of modifier, accumulation potential and time, and electrolyte pH value were respectively discussed. Under the optimized conditions, two linear ranges of 0.002- 0.1 μM and 0.1–10 μM were obtained, with a detection limit of 1 nM (S/N = 3). The method was applied in Qu determination in blueberry juice with the recoveries of 102.5–105.0%.
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JOURNAL OF CHROMATOGRAPHY A
·
2020
·
IF 4.049
Alula Yohannes,Xueting Feng,Shun Yao
Nowadays, enantioseparation of racemic pharmaceuticals in preparations is a prime concern by drug authorities across the globe. In the present work, it was attempted to develop novel enantioselective extraction method for five clinically used drugs (atenolol, propranolol, metoprolol, racecadotril, and raceanisodamine in their tablets) as racemates. The enantioselective solid-liquid extraction of these racemic drugs was carried out successfully by the use of chiral ionic liquid (CIL) in combination with a metal organic framework (MOF) for the first time. The composite CIL@MOF was synthesized from tropine based chiral ionic liquids with L-proline anion ([C n Tr][L-Pro], n =3–6) and HKUST-1 type MOF , which was comprehensively characterized before being used as sorbent for enantioselective dispersive solid-liquid extraction. Preliminary selection of appropriate CIL was carried out on thin layer chromatography (TLC); under the joint participation of copper ion in the developing reagent, [C 3 Tr][L-Pro] ionic liquid showed better resolution performance with ΔR f value of 0.35 between the enantiomers was obtained for racemic atenolol. Moreover, the effect of copper salt dosage, amount of CIL, soli-liquid ratio and extraction time were investigated. The optimal conditions were obtained after thorough investigations; i.e. sample solution: ethanol, elution solvent: methanol, solid-liquid ratio: 12.5 mg:50 mL, amount of copper salt: 8 mg L −1 , amount of impregnated CIL: 30% and extraction time of 30 min. As a result, enantiomeric excess values are 90.4%, 95%, 92%, 81.6% and 83.2% for atenolol, propranolol, metoprolol, racecadotril and raceanisodamine, respectively. The developed enantioselective method was validated following ICH guidelines and it was proved to be simple, effective and enantioselective way for separation of racemic pharmaceuticals with similar behaviors.
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GREEN CHEMISTRY
·
2020
·Vol. 22
·期 6
·1944-1951
·
IF 9.48
Anlian Zhu,Wanlu Feng,Zhiyong Li,Shuang Cheng,Qianhan Chen,Dongshuang Fan,Yuanyang Guo,Lingjun Li,Jianji Wang
The great challenges of modern industry and the environment make it important to develop sustainable energy resources with low cost. In this work, a cleaner enzymatic procedure for biodiesel production was developed through the utilization of a biocompatible and hydrophilic ionic liquid [Choline][H2PO4]. This ionic liquid can be synthesized from cheap raw materials through simple neutralization procedures, and it has been proved to be well biocompatible. The utilization of this ionic liquid in Novozym 435 catalyzed biodiesel production makes the reaction and work-up procedures very simple, because its hydrophilicity can lead to the implementation of a pseudo homogeneous reaction and then heterogeneous separation. Various oil resources such as triolein, sunflower oil and castor oil can all be converted to biodiesels with high yields. After the completion of reaction, both the ionic liquid and Novozym 435 can be recycled and reutilized for at least five cycles without a significant activity decrease. In addition, this reaction system can be conveniently scaled up to the multi-gram level with high efficiency and feasible separation. Overall, the above mentioned benefits make this ionic liquid based enzymatic system cleaner for the production of biodiesel and promising for further industrial applications.
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Green Energy & Environment
·
2020
·
IF 6.395
Lu Gan,Jiachen Guo,Siying Che,Qiaoxin Xiao,Mingyang Wang,Jienan You,Congmin Wang
Specific fluorophore was introduced into ionic liquid based on its tunability, thus a kind of novel fluorescent ionic liquid probe [P 66614 ][HQS] was designed, synthesized and characterized. Compared with non-fluorescent HQS, ionic liquid [P 66614 ][HQS] emitted a certain amount of fluorescence, which could be attributed to the well-delocalized frontier orbitals and its charge transfer character, as demonstrated by quantum chemical calculation. Considering the interaction of [P 66614 ][HQS] with metal ions, the application for detecting specific substance as a chemical sensor, such as Al 3+ was investigated. Compared with the traditional probe HQS, significant improvements in Al 3+ detecting was achieved by [P 66614 ][HQS] with stronger binding ability, better sensitivity and selectivity. The better performance of [P 66614 ][HQS] was contributed to the changed charge distribution, leading to the stronger binding interaction. We believe that this new fluorescent ionic liquid exhibited unique properties in detecting Al 3+ in aqueous solution, which would broaden the application of ionic liquids.
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ACS Sustainable Chemistry & Engineering
·
2020
·
IF 7.632
Xiaohui Di,Yu Zhang,Junying Fu,Qiang Yu,Zhongming Wang,Zhenhong Yuan
Dimethyl itaconate (DI), a promising biomass-derived intermediate, cannot be synthesized from itaconic acid (IA) in organisms due to the lack of metabolic pathways. It is necessary to develop a green and high-efficiency method to synthesis DI from IA. In this study, DI was, for the first time, produced from IA in an aqueous medium by an ionic liquid-strengthened enzymatic method. We found that when pretreated by the ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]), the pH tolerance range of the lipase shrunk and the hydrolysis activity of it was greatly inhibited, while its esterification activity was not. Moreover, when the [bmim][PF6]-treated immobilized Rhizomucor miehei lipase (RML, 50 mg/mL) was employed in a reaction containing IA/methanol at a molar ratio of 1:30 and methanol/water in a volume ratio of 1:10 at 30 °C after 24 h, a 64.3% yield and 73.2% selectivity of DI was obtained. The results of HPLC and GC–MS revealed that in addition to the main product DI, other side products including acetic acid, propionic acid, and itaconic acid cyclolactone were also generated, which indicates that the RML-catalyzed esterification of IA and methanol has various side reactions, such as lactonization and self-decomposition of IA.
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JOURNAL OF CHROMATOGRAPHIC SCIENCE
·
2020
·Vol. 58
·期 6
·576-584
·
IF 1.28
Li Kai,Liu Zhongling,Liu Yue,Zhang Hanqi,Yu Wei
An ultrasound-assisted ionic liquid (IL) salting-out microextraction system was developed and applied for the extraction of quinolone antibiotics from urine. A precipitate was formed from the salt and IL, and it acted as the sorbent for the analytes. The precipitate containing the analyte was separated by filtration, redissolved, and the solution then was evaporated. The resulting extract was redissolved for high-performance liquid chromatographic analysis. Several parameters, including type and volume of IL, the type and amount of salts, sample pH, temperature and extraction time were optimized. Under the optimal experimental conditions, the limits of detection for fleroxacin and ciprofloxacin were 3.12 and 4.97 μg L−1, respectively. When the present method was applied to real urine sample analysis, the analyte recoveries ranged from 82.3 to 106.8%. This ultrasound-assisted IL salting-out microextraction system had the characteristics of high recoveries, shorter separation time and easy-to-perform collection procedure, which yielded the method to have potential for wide application.
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2020
·
IF 4.939
Kai Li,Jia Chen,Mingming Guan,Shaokun Tang
The “trade-off” effect between hydroxide conductivity and dimensional stability is challenging issue for anion exchange membrane fuel cells (AEMFCs). In this study, the framework of UiO-66-NH 2 is for the first time applied to anion exchange membranes (AEMs). The robust pore walls of UiO-66-NH 2 with mechanical and structural durabilities protect the membrane from the excessive swelling effects (a swelling ratio of 7%). In addition, the framework of UiO-66-NH 2 is directly modified into (UiO-66-NH 2 ) + Cl − as hydroxide conduction channels by anion stripping for the first time. And we construct well-organized ion nanochannels by the in-situ self-assembly of N,N,N′,N' -tetramethyl-1,6-hexanediamine (TMHDA) and allyl bromide within the highly ordered pores of (UiO-66-NH 2 ) + Cl − . The obtained QA@(UiO-66-NH 2 ) + Cl − then incorporated into pristine membrane (QAPPO) to fabricate the novel multi-channel AEMs. The hydroxide conductivity of QA@(UiO-66-NH 2 ) + Cl − /PPO is up to 123 mS⋅cm −1 at 80 °C, which is greatly improved compared to QAPPO pristine membrane.
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SEPARATION AND PURIFICATION TECHNOLOGY
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2020
·
IF 5.774
Jiuli Han,Lu Bai,Shuangjiang Luo,Bingbing Yang,Yinge Bai,Shaojuan Zeng,Xiangping Zhang
Ionic liquids (ILs) are attractive and prospective materials used in membranes due to the nonvolatility, structure tunability, and the ability to tune the interface compatibility. The cobalt IL Bmim 2 Co(NCS) 4 possesses the porphyrin-like N4-coordinated cobalt center which could selectively and reversibly interact with O 2 . Herein the Bmim 2 Co(NCS) 4 as liquid-phase oxygen carrier was used to fabricate thin-film composite (TFC) membrane with the polymer of intrinsic microporosity (PIM-1). The microstructures, properties and gas separation performance of the membrane were compared with the TFC membrane which takes cobalt porphyrin (T(4-Cl)PPCo) as a carrier. We found that the addition of a small amount of T(4-Cl)PPCo can enlarge the d -spacing of packed chains of PIM-1 and significantly increase the fractional free volume (FFV) and the gas permeability of the membrane, but the selectivity is unsatisfactory. It is worth noting that adding Bmim 2 Co(NCS) 4 into the polymer can increase greatly the O 2 /N 2 selectivity which is higher than that of the membrane with T(4-Cl)PPCo. Although the addition of Bmim 2 Co(NCS) 4 decreases the d -spacing of packed chains of PIM-1, resulting in the slight decline of FFV and gas permeability of the membrane, the Bmim 2 Co(NCS) 4 /PIM-1 TFC membranes exhibit better O 2 /N 2 separation performance than the T(4-Cl)PPCo/PIM-1 TFC membranes in consideration of the Robeson upper bound.
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JOURNAL OF MEMBRANE SCIENCE
·
2020
·
IF 7.183
Yun Yang,Qian Wu,Dong Wang,Chenchong Ma,Zheng Chen,Qinting Su,Caizhen Zhu,Cuihua Li
The composite solid electrolytes (CSEs) inherits the high safety of the inorganic solid electrolyte and the easy processing of the organic polymer electrolyte , thereby exhibiting a broad application prospect. However, the performance of the CSE was hard to realizing its practical application in lithium metal batteries . Herein, the significant impact of CSE performance brought about by the addition of ionic liquids was studied and summarized: significantly increase ionic conductivity ; constructing a viscoelastic interface between electrode and electrolyte to reduce the interface impedance; forming a stable and LiF-rich SEI at the negative electrode to inhibit the growth of lithium dendrites ; wetting the LiFePO 4 porous cathode. The LiFePO 4 /CSE-60/Li battery displays high initial discharge specific capacity of 158.2 mAh g −1 and a capacity retention of 86.3% after 400 cycles at 1 C at 55 °C, and with coulombic efficiency of 99.7%. The surface of the lithium metal anode after long-term cycling exhibits to dendrite-free morphology. This research highlights the critical role that ionic liquids play in improving the performance of CSEs and will shed light on designing CSEs for LMB practical applications.
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FOOD CHEMISTRY
·
2020
·
IF 6.306
Tenghe Zhang,Wencai Huang,Tingting Jia,Yuqiao Liu,Shun Yao
A new kind of multi-component membrane was prepared by combining gelatin solution, porogen and an inclusion complex of ionic liquid (IL) and beta-cyclodextrin (β-CD) in a simple physical manner for selective separation of tea polyphenols (TPs) from green tea crude extracts. After screening, it was found that the resulting membrane containing the IL of dicationic N -vinylimidazole proline salt ([VIm] 2 C 3 [ l - pro ] 2 ) had the excellent performance for the enrichment of the target molecules. Then the newly-developed film was comprehensively characterized by scanning electron microscopy, conductivity, thermogravimetry and spectral analysis. Under pressure driving, the adsorption from an aqueous solution of a mixture of TPs and theophylline on IL@β-CD-Gel membrane showed that the adsorption capacity for TPs was 303.45 mg/g with removal percentages of 94.38%. The experimental data fit well with pseudo-second-order model and Freundlich model. By using this composite material, a new technology of membrane separation for selective adsorption of TPs was finally established.
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JOURNAL OF MOLECULAR LIQUIDS
·
2020
·
IF 5.065
Linghua Zhuang,Fei Zhong,Mengyi Qin,Yu Sun,Xiaoyan Tan,Huiwen Zhang,Mengke Kong,Kehui Hu,Guowei Wang
Two imidazolium chloride ionic liquids (ILs) were mixed with urea for chitosan dissolution. Ionic liquids were [Amim]Cl and [Etmim]Cl (1-allyl-3-methyl-imidazolium chloride and 3-methyl-1-(ethylacetyl)imidazolium chloride, respectively). Physicochemical properties of neat ILs and IL-Urea solutions (including density, viscosity, conductivity, β value, π* value, and thermogravimetric analysis), were thoroughly investigated. Dissolution performance of chitosan in IL-Urea solutions was determined. Chitobiose (KET) as model chitosan structure, density functional theory (DFT) calculations were used to discuss the interactions between IL, urea, and chitobiose, and to clarify the different physicochemical properties of ILs, IL-Urea solutions. Also DFT simulation results were used for elucidating the influence of different cationic substituents and urea addition for chitosan dissolution. [Etmim]Cl showed higher density, viscosity, conductivity, β, and π* value than those of [Amim]Cl. These results revealed strong hydrogen bonds among [Etmim]Cl owing to the carboxylic acid ester group than allyl group of [Amim]Cl. Densities, viscosities, and π* values of IL-Urea solutions increased with increasing urea content. Conductivities and β values of IL-Urea solutions decreased with the increase of urea content at same temperature. The thermal stability of [Amim]Cl-Urea mixture increased when urea content increased from 10% to 30%, which was different from [Bmim]Cl-Urea melt. The thermal stability of [Etmim]Cl-Urea mixture was different to that of [Amim]Cl-Urea mixture. Urea was accommodated in ILs, forming hydrogen bonds with both the anion and cation in ILs, which changed the molecular interactions of ILs. The influence of different substituents in imidazolium ILs and urea addition on chitosan dissolution were analyzed using experimental determination and DFT calculations. Cationic substituents of imidazolium ILs play an extraordinary role in hydrogen bonds formation with chitobiose, so to strengthen chitosan dissolution. The information obtained would provide a guide for designing novel IL solvent systems for chitosan dissolution.
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Analytical Methods
·
2019
·Vol. 12
·期 3
·324-332
·
IF 2.378
Ranxi Ni,Jingdong Peng,Miaomiao Wen,Huanjun Peng,Zhongying Zhang,Shiyu Li,Xiang Wang,Jun Chen,Dengying Long,Hong Xian
A novel imidazolium ionic liquid mixed-mode stationary phase (named IBON) was successfully prepared by a controlled thiol-initiated radical polymerization method. The successful preparation of the IBON stationary phase was certified by Fourier transform infrared (FT-IR) spectrometry, elemental analysis, scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). Meanwhile, the zeta potential showed the surface potential of the IBON stationary phase, while the results of gel permeation chromatography (GPC) demonstrated the successful control of the surface-initiated polymerization. The retention behaviour was investigated by various types of analytes, including acidic compounds, basic compounds and neutral compounds (containing polar nucleosides and bases, non-polar benzene series). Through investigating the influence of the acetonitrile content, pH of the mobile phase, buffer concentration on the retention and by employing the van't Hoff equation and linear solvation energy relationships model, it was found that the various test solutes could undergo multiple interactions with the IBON stationary phase, including hydrophobic, electrostatic, dipole–dipole, hydrogen bonding, ion exchange and π–π interactions. The prepared stationary phase was employed to separate polar solutes, benzene series, and inorganic anions, and it displayed different separation characters when compared to the commercial Acclaim™ Mixed-mode WAX-1 column.
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危险品化学品经营许可证（带存储）