共查询到20条相似文献,搜索用时 15 毫秒
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Francisco J. Deive Ana Rodríguez Isabel M. Marrucho Luís P.N. Rebelo 《The Journal of chemical thermodynamics》2011,43(11):1565-1572
The specific effects of K3PO4, K2CO3, Na2CO3, and (NH4)2SO4, as high charge-density inorganic salts and thus inducers of the formation of aqueous biphasic systems (ABS) containing several ethyl-methylimidazolium alkylsulfate ionic liquids, C2MIM CnSO4 (n = 2, 4, 6, or 8), have been assessed at T = 298.15 K. The results are analyzed in the light of the Hofmeister series. The influence of different alkyl chain lengths in the anion, together with the ability of the selected inorganic salts to induce the formation of ABS, is discussed. Phase diagrams have been determined through turbidimetry, including tie lines assignments from mass phase ratios according to the lever – arm rule. The Merchuck equation was satisfactorily used to correlate the solubility curve. 相似文献
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Atsushi Kimura Mitsumasa Taguchi Takafumi Kondoh Jinfeng Yang Ryuji Nagaishi Yoichi Yoshida Koichi Hirota 《Radiation Physics and Chemistry》2010,79(11):1159-1164
In this article, we report the reaction of halophenols with solvated electrons in room-temperature ionic liquids (RTILs) initiated by γ-ray and pulsed electron radiolyses. The decomposition G-values of ortho-chlorophenol (CP) in N-methyl-N-propylpyrrolidinium–bis(trifluoromethanesulfonyl)imide (TFSI), N-butyl-N-methylpyrrolidinium–TFSI and N-methyl-N-propylpiperidinium–TFSI were estimated to be 1.4, 1.6, and 1.7 molecules 10?2 eV?1 under γ-ray irradiation; these values were almost the same as the yield of solvated electron formation. The second-order rate constant for the reaction of CP with solvated electrons in diethylmethyl(2-methoxyethyl)ammonium (DEMMA)–tetrafluoroborate (BF4) was one order of magnitude lower than that in DEMMA–TFSI although the G-values of CP decomposition and phenol formation in DEMMA-BF4 were higher. The decomposition yield of ortho-iodophenol in DEMMA–TFSI was slightly higher than that of the other halophenol (ortho-fluorophenol, CP, and ortho-bromophenol), and the formation yield of phenol for the decomposition of only ortho-fluorophenol was lower. 相似文献
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吡啶类离子液体在汽油萃取脱硫中的应用研究 总被引:17,自引:0,他引:17
利用合成的六种吡啶类离子液体,N-丁基吡啶硝酸盐离子液体([BPy]NO3),N-乙基吡啶硝酸盐离子液体([EPy]NO3),N-丁基吡啶四氟硼酸盐离子液体([BPy]BF4),N-乙基吡啶四氟硼酸盐离子液体([EPy]BF4)、N-乙基吡啶乙酸盐([EPy]Ac)、N-丁基吡啶乙酸盐([BPy]Ac),进行了汽油萃取脱硫的应用研究。结果表明,[BPy]BF4的脱硫效果最好,[EPy]BF4的脱硫效果最差。[BPy]BF4对模型化合物单程脱硫率达到45.5%,可以有效地脱除汽油中的含硫化合物,使用过的离子液体可以通过真空加热或用四氯化碳反萃取再生。 相似文献
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V. V. Okhlobystina A. O. Okhlobystin Yu. Yu. Koldaeva N. O. Movchan A. A. Litvin N. T. Berberova 《Russian Journal of General Chemistry》2013,83(11):2062-2065
We consider the possible application of pyridinium ionic liquids to desulfurize hydrocarbon raw products and to transform the extracted toxic admixtures into promising sulfur compounds. Anodic oxidation of the extracted thiols as well as oxidation in the presence of electron mediators (N,N,N′,N′-tetramethyl-1,4-phenylenediamine, tri-p-bromophenylamine, and tri-p-tolylamine) leads to the corresponding disulfides. 相似文献
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Catalytic reactions in two liquid phases containing ionic liquids (ILs), in which organic reactions proceed in the ILs phase and products are extracted to the other liquid phase, are efficient and environmentally benign. This short review briefly reports the development of catalytic application in biphasic systems containing ILs in the last two years. Recent progress for the functionalization of ILs themselves and combinations of homogeneous and heterogeneous catalysts with ILs are described. Prospects and future challenges are also addressed. 相似文献
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Paulina Dróżdż 《Natural product research》2019,33(1):148-151
Room temperature ionic liquids are novel solvents with the specific properties that makes them of interest for application for extraction for a wide range of compounds. In this work extraction efficiency of flavonoids from heather flowers using ionic liquids based on imidazolium cation were evaluated and compared with organic solvents. It was found that the anion of ionic liquid significantly influence the extraction yields. Flavonoid content as well as antioxidant activity based on radical scavenging on 1,1-diphenul-2-pirylhydrazyl radicals and cupric reducing antioxidant capacity increased in the order: [Bmim]PF6 < [Bmim]BF4 < [Bmim]Cl. The obtained extraction yield using [Bmim]Cl were higher than reported for 60% ethanol and ethyl acetate under similar conditions, thus, may be helpful for better utilization of heather flowers as the potential pharmaceutical and nutraceutical ingredients. 相似文献
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Bösmann A Datsevich L Jess A Lauter A Schmitz C Wasserscheid P 《Chemical communications (Cambridge, England)》2001,(23):2494-2495
A new approach for the deep desulfurization of diesel fuels by extraction with ionic liquids is described. 相似文献
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Amino acid ionic liquids (AAILs) have received great attention due to their potentials in catalysis and separations. In this work, functional AAILs were used as solvent and selector in chiral liquid–liquid extraction for the first time. The AAILs have shown distinct enantioselectivity in amino acid extraction. Using these functional AAILs as acceptor phase and ethylacetate as donor phase, more L-enantiomer of amino acid was extracted into the ionic liquid phase than that of D-enantiomer. The influencing factors, including AAILs structure, copper ion concentration, organic phase and amino acid concentration, were investigated. We found that the enantioselective enrichment of racemic amino acids was achieved through a chiral ligand-exchange mechanism. The enantioselectivity of single-step extraction was up to enantiomeric excess value of 50.6%. Moreover, the functional AAILs were found to be efficient extraction solvents for amino acids. The logarithm of distribution coefficient for L-Phe was in the range of 3.4–3.6 in the ionic liquid–ethylacetate two-phase system. This liquid–liquid extraction approach may extend the application of ionic liquids in chiral separations. 相似文献
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有效萃取复杂食品样品中的极性污染物是实现其准确测定的瓶颈,也是食品安全分析的难点。针对污染物的结构特点,设计和发展能与之产生特定作用的新型材料是高效萃取的关键。敌草快是一种广谱性除草剂,为碱性的阳离子有机化合物。该文以1-乙烯基咪唑和1,3-丙磺酸内酯为原料合成了磺酸功能化的离子液体,通过自由基聚合反应,将其固载至磁性纳米颗粒表面,得到磺酸功能化的聚(1-乙烯基-3-丙基磺酸基咪唑氯盐)修饰的磁性纳米颗粒(Poly([VPImi-SO3H][Cl])-MP)。采用红外光谱、扫描电镜、振动样品磁强计和热重分析等对其结构、形貌和磁性进行了表征。将其作为磁性固相萃取的吸附剂,萃取青菜中的敌草快。磺酸基的功能化使Poly([VPImi-SO3H][Cl])-MP的表面在一定pH下带有丰富的负电荷,与敌草快之间产生强的静电吸引作用,可实现对敌草快的有效萃取。对影响萃取效率的各种参数如溶液pH、吸附剂质量、吸附时间、解吸剂种类和体积等进行了优化。在优化条件下,结合磁性固相萃取和高效液相色谱技术,对方法的性能及适用性进行了考察。敌草快在0.2~20μg/g... 相似文献
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The products of transformation of elemental sulfur in benzene solutions in the presence of ionic liquids under microwave irradiation have been studied by NMR. It has been shown that some ionic liquids can cease to be chemically inert and react with elemental sulfur. 相似文献
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This paper reports a novel pressure sensor with an electrical readout based on electrofluidic circuits constructed by ionic liquid (IL)-filled microfluidic channels. The developed pressure sensor can be seamlessly fabricated into polydimethylsiloxane (PDMS) microfluidic systems using the well-developed multilayer soft lithography (MSL) technique without additional assembly or sophisticated cleanroom microfabrication processes. Therefore, the device can be easily scaled up and is fully disposable. The pressure sensing is achieved by measuring the pressure-induced electrical resistance variation of the constructed electrofluidic resistor. In addition, an electrofluidic Wheatstone bridge circuit is designed for accurate and stable resistance measurements. The pressure sensor is characterized using pressurized nitrogen gas and various liquids which flow into the microfluidic channels. The experimental results demonstrate the great long-term stability (more than a week), temperature stability (up to 100 °C), and linear characteristics of the developed pressure sensing scheme. Consequently, the integrated microfluidic pressure sensor developed in this paper is promising for better monitoring and for characterizing the flow conditions and liquid properties inside the PDMS microfluidic systems in an easier manner for various lab on a chip applications. 相似文献
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Ultrasonication-assisted extraction and preconcentration of medicinal products from herb by ionic liquids 总被引:1,自引:0,他引:1
Ionic liquid-based extraction of medicinal or useful compounds from plants was investigated as an alternative to supercritical fluid, cloud point and conventional organic solvent extractions. The method integrated extraction and preconcentration. Medicinal products were first extracted by an ionic liquid solution, part of which was then converted to a hydrophobic form by anion metathesis for preconcentration. The remaining soluble ionic liquid acted as a dispersive agent to enhance the efficiency of preconcentration. Protein in the extract was precipitated spontaneously without addition of further solvents. Ultrasonication assisted this method for extraction and preconcentration of cryptotanshinone, tanshinone I and tanshinone II A from Salvia Miltiorrhiza Bunge. 0.233 mg g−1, 0.695 mg g−1 and 0.682 mg g−1 of each, respectively, were extracted using [OMIM][Cl], and preconcentrated in a [OMIM][PF6] phase at respective concentrations of 148.1, 507.1 and 486.1 μg mL−1. The method exhibited potential applicability with other medicinal products. 相似文献
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Boelo Schuur 《Chemical Papers》2015,69(2):245-253
Since the late 1990’s there has been a tremendous growth in literature on ionic liquids (ILs) for a broad range of applications, i.e. catalysis, electrolytes for batteries, in solvolysis of biomass, and also in separation technology. ILs can be applied as solvents for absorption (e.g. of CO2), extractive distillation and extraction processes. That ILs are not magic solvents but have their limitations has also become evident during the past years. Especially the high costs associated with ILs and the lack of experience with these materials in the industrial practice are factors limiting industrial adoption of ILs. The often praised versatility of properties that can be achieved through combination of different cations and anions generates a huge amount of options and makes it difficult to decide where to start when selecting/designing a solvent. This paper focuses on solvent selection/design for applications in extractive distillations and liquid-liquid extractions; also, solvent performance in several specific case studies taken from the open literature is discussed. Important recommendations include: a) make a conceptual process design including the recovery step, regeneration of the IL may be a critical parameter; b) if extractions from aqueous streams are studied, the uptake of water by the IL is an important factor because such co-extracted water is evaporated during the regeneration; c) compare the process with conventional processes to check whether it performs better than the state-of-the-art in industry. 相似文献
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A novel method: ionic liquid-based ultrasound-assisted extraction of polyphenols from Chinese purple yam 总被引:1,自引:0,他引:1
Junhong Zhang Aizhen Zong Tongcheng Xu Ping Zhan Lina Liu Bin Qiu 《Natural product research》2018,32(7):863-866
Chinese purple yam is famous for therapeutic and nutritional values in lowering blood glucose, blood pressure and even preventing and treating cardiovascular diseases. However, traditional extraction techniques for the functional polyphenolic compounds mostly utilise unfriendly organic solvent and easily cause degradation of polyphenols. In this study, a novel ionic liquid-based ultrasound-assisted extraction (IL-UAE) technique was utilised to obtain polyphenols. The optimal extraction condition included: solid–liquid ratio (0.05 g/mL), ionic liquid concentration (1.05 M), extraction temperature (67°C) and ultrasonic time (37 min). The maximum free radical scavenging activity (86.21%) and total antioxidant activity (2.21 mM) were achieved and matched well with the predicted values, superior to that of the extract from regular ethanol-based UAE. IL-UAE could be a rapid and green technique for efficient extraction of polyphenols from purple yam with low solvent consumption and few structural deterioration, exhibiting application potential in food and pharmaceutical industries. 相似文献
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Stepnowski P 《Analytical and bioanalytical chemistry》2005,381(1):189-193
Owing to their favorable properties, ionic liquids have recently gained recognition as possibly environmentally benign solvents. Now among the most promising industrial chemicals, they have already been labeled green, but this appellation seems due entirely to their very low vapor pressure. This growing interest in the various applications of ionic liquids will soon result in their presence in the environment. Therefore, reliable analytical tools for the environmental analysis of ionic liquids need to be developed urgently. This paper presents a newly developed analytical procedure for the enrichment of 1-alkyl- and 1-aryl-3-methylimidazolium ionic liquids from water samples. The method is based on cation exchange solid-phase extraction followed by selective elution. Pre-concentrated samples are subjected to high-performance liquid chromatography (HPLC) with an advanced methodology for qualitative and quantitative analysis. The overall procedure was verified by using standard spiked samples of tap water, seawater, and freshwater. 相似文献
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The preliminary results described here show the complete transfer of Hg(II) ions, in the absence of a chelating agent in 1-alkyl-3-methylimidazolium hexafluorophosphate ionic liquids; the lag time required to gain the quantitative metal ion partition turned out to be strongly dependent both on alkyl chain length on the imidazolium ring and on the working temperature. 相似文献
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The rate constants of a bimolecular Diels-Alder reaction in binary mixtures of ionic liquids prepared in molecular solvents were analyzed to investigate the effect of viscosity of the medium and solvent effect. In this connection, we have carried out the Diels-Alder reaction of anthracene 9-carbinol with N-ethyl maleimide in binary mixtures of pyridinium-based ionic liquids, 1-butyl-pyridinium tetrafluoroborate, 1-butyl-3-pyridinium tetrafluoroborate, and 1-butyl-4-methyl pyridinium tetrafluoroborate in water, methanol, and chloroform at 298.15 K. The rates of reaction decreased, caused by gradually increasing the volume fraction of ionic liquids in solvents for all three ionic liquids. The kinetic results demonstrate a successful application of the pairwise interaction model built upon the concept of enforced hydrophobic hydration. A temperature-dependent study of kinetics of the Diels-Alder reaction was carried out in the binary mixtures of ionic liquids in water and was explained by the entropy-enthalpy compensation effect based upon activation parameters. Kinetics of the Diels-Alder reaction in highly aqueous medium was noted to be entropically driven. 相似文献