离子液体用于乙酸乙酯-甲醇共沸物系的研究

选择铵盐类离子液体作为萃取精馏分离乙酸乙酯-甲醇共沸体系的萃取剂。测出了101.3 kPa下含有离子液体三丁基甲基醋酸铵([N_(4441)][Ac])或三丁基甲基丙酸铵([N_(4441)][Pr])的乙酸乙酯-甲醇共沸混合物的三元汽液平衡数据。使用非随机双液体模型(NRTL)对实验数据进行关联,并得到相关参数。[N_(4441)][Ac]和[N_(4441)][Pr]的加入都对体系产生了显著的盐析效应。随着[N_(4441)][Ac]或[N_(4441)][Pr]摩尔分数的增大,盐析效应愈发明显,最终共沸现象都能够被完全打破。通过NRTL方程拟合得出[N_(4441)][Ac]和[N_(4441)][Pr]最小打破共沸的摩尔分数分别为0.045和0.047。2种离子液体的分离能力为[N_(4441)][Ac][N_(4441)][Pr]。     

功能化离子液体催化合成柠檬酸三丁酯

研究了功能化离子液体3-N,N,N-三甲铵基丙磺酸硫酸氢铵盐([TMPS]·[HSO4])催化柠檬酸和正丁醇反应合成柠檬酸三丁酯的新方法。结果表明,[TMPS]·[HSO4]具有很高的催化活性,n(C6H8O7):n(C4H9OH)=1:3.5时在125～130℃下反应3.0h,酯化率达到99﹪;反应结束后产物与催化体系分层,简化了分离过程;离子液体可以循环使用9次,催化活性无明显变化。与传统工艺相比,反应时间较短、反应温度较低、副反应少,且不使用有机溶剂作为带水剂。     

基于离子液体的“可设计性”和“软酸”性质萃取分离电镀污泥中Cr~(6+)/Fe~(3+)

基于离子液体的"可设计性"和"软酸"性质对于其在电镀污泥酸浸液中铬铁萃取分离方面的应用及其机理进行研究。结果表明:咪唑环上烷基链的长度对于铬铁萃取分离效果有较大的影响,阴离子为[BF_4]~-的离子液体对于铬铁萃取分离能力大于阴离子为[PF_6]~-的离子液体。在所研究的离子液体中,[Omim][BF_4]对于铬铁具有较好的萃取分离效果,实现了电镀污泥中铬铁分离。结合斜率法、红外光谱分析、Raman光谱分析,[Omim][BF_4]萃取铬符合离子缔合机理,可推测[Omim][BF_4]咪唑阳离子与Cr_2O_7~(2-)阴离子形成离子缔合物而进入有机相,达到萃取分离,从而实现电镀污泥资源化目的,具有一定的应用性。     

疏水性离子液体萃取芳香化合物及其再生

利用疏水性离子液体1-丁基-3-甲基咪唑六氟磷酸盐[Bmim][PF6]、1-丁基-3-乙基咪唑六氟磷酸盐[Beim][PF6]、1-丁基-3-甲基咪唑双三氟甲磺酰亚胺盐[Bmim][Tf2N]对水溶液中的9种芳香化合物进行萃取,以苯胺为代表对萃取工艺进行了优化,考察了乙醚、正丁醇等低极性溶剂对离子液体的再生情况. 结果表明,在室温下,当相比O/A=0.2、时间为10 min时,[Bmim][PF6]对苯胺的萃取率达87.2%,分配系数为34.1,效果明显高于甲苯、正辛醇等传统有机溶剂. 芳香化合物的分子结构对萃取有较大影响,萃取率及分配系数随溶质疏水性增加而增加. 用乙醚作为反萃剂效果较好,苯胺和离子液体的回收率分别为93.1%和95.2%,溶质及离子液体均能实现资源化回收利用.     

胆碱脯氨酸/RTILs支撑液膜的CO_2/N_2分离性能

选用不同种类的室温型离子液体(RTILs)与胆碱脯氨酸离子液体进行混合分别制得[Choline][Pro]/[EMIm][N(CN)_2]、[Choline][Pro]/[bmim][PF_6]以及[Choline][Pro]/[HMIm][NTf_2]混合离子液体,并将其应用于离子液体支撑液膜(SILMs)。考察操作温度、操作压差、RTILs种类和含量对SILMs分离CO_2/N_2性能的影响。结果表明胆碱脯氨酸/RTILs系列SILMs的CO_2通量在343.3~1936.9 barrer之间变化并且CO_2/N_2选择性为10.3~34.8。对CO_2膜过程内在机制探索表明随着[HMIm][NTf2]离子液体在混合离子液体中比例的增加,总阻力1/Kμ会呈现先降低后升高的趋势。与实验现象中随着[HMIm][NTf2]离子液体在混合离子液体中比例的增加CO_2先升高后降低相符。     

离子液体[BMIm]NTf2中Ni纳米颗粒的制备及其催化性能研究

微波辐射下合成了1-丁基-3-甲基咪唑双三氟甲基磺酰亚胺（[BMIm]NTf2）离子液体,并采用IR和1HNMR验证了其结构。利用化学还原法分别在水溶液和离子液体[BMIm]NTf2中制备了Ni纳米颗粒,采用XRD、TEM对其结构进行表征,并考察这两种纳米Ni颗粒在邻硝基苯催化加氢反应中的催化性能。结果表明,[BMIm]NTf2中制备的Ni纳米颗粒为面心立方结构,粒径在3—30nm。在还原过程中,离子液体同时起到了溶剂和修饰剂的作用,在所生成的M纳米颗粒的表面形成了一层离子液体的修饰层,阻止了Ni纳米粒子之间的团聚;在相同条件下,[BMIm]NTf2中制备的纳米Ni颗粒的催化活性显著高于常规水性介质中制备的Ni催化剂。     

酸性离子液体催化丁烯酯化反应制备乙酸仲丁酯

采用两步法合成了[Bmim]HSO_4,[Bmim]Sb F6,Bmim]PF6,[BSmim]HSO_4,[BSmim]CF_3SO_3,[BSN222]H_2PW_12O_40,[Ph3PSO3H]HSO_4等离子液体,以离子液体及离子液体/酸性无机盐为催化剂,在90℃、混合碳四:乙酸体积比18:5、乙酸:催化剂摩尔比2、反应时间4 h条件下,催化丁烯与乙酸的酯化反应.结果表明,以[Ph_3PSO_3H]HSO_4为催化剂时,丁烯转化率、乙酸仲丁酯的选择性和收率分别达88.8%,100.0%和88.8%,远高于以浓H_2SO_4催化的转化率(73.5%)、选择性(77.7%)和收率(57.1%).以[Ph_3PSO_3H]HSO_4为催化剂的8次循环实验中,总丁烯转化率均大于88.4%,乙酸仲丁酯选择性均大于97.4%,且产物与离子液体易分离,催化效果和循环使用性能良好.     

基于离子液体的“可设计性”和“软酸”性质萃取分离电镀污泥中Cr6+/Fe3+

基于离子液体的"可设计性"和"软酸"性质对于其在电镀污泥酸浸液中铬铁萃取分离方面的应用及其机理进行研究。结果表明：咪唑环上烷基链的长度对于铬铁萃取分离效果有较大的影响,阴离子为[BF₄]^-的离子液体对于铬铁萃取分离能力大于阴离子为[PF₆]^-的离子液体。在所研究的离子液体中,[Omim] [BF₄]对于铬铁具有较好的萃取分离效果,实现了电镀污泥中铬铁分离。结合斜率法、红外光谱分析、Raman光谱分析,[Omim] [BF₄]萃取铬符合离子缔合机理,可推测[Omim] [BF₄]咪唑阳离子与Cr₂O₇^2-阴离子形成离子缔合物而进入有机相,达到萃取分离,从而实现电镀污泥资源化目的,具有一定的应用性。     

离子液体[BMIm]NTf_2中Ni纳米颗粒的制备及其催化性能研究

微波辐射下合成了1-丁基-3-甲基咪唑双三氟甲基磺酰亚胺([BMIm]NTf2)离子液体,并采用IR和1H NMR验证了其结构。利用化学还原法分别在水溶液和离子液体[BMIm]NTf2中制备了Ni纳米颗粒,采用XRD、TEM对其结构进行表征,并考察这两种纳米Ni颗粒在邻硝基苯催化加氢反应中的催化性能。结果表明,[BMIm]NTf2中制备的Ni纳米颗粒为面心立方结构,粒径在3～30 nm。在还原过程中,离子液体同时起到了溶剂和修饰剂的作用,在所生成的Ni纳米颗粒的表面形成了一层离子液体的修饰层,阻止了Ni纳米粒子之间的团聚;在相同条件下,[BMIm]NTf2中制备的纳米Ni颗粒的催化活性显著高于常规水性介质中制备的Ni催化剂。     

离子液体液液萃取分离正辛烷/邻二甲苯

将直馏石脑油分离为脂肪烃和芳烃有助于实现石脑油资源的优化利用,溶剂萃取是芳烃/脂肪烃分离的重要途径,萃取剂的设计与优选对萃取过程至关重要。实验探究了多种离子液体对正辛烷/邻二甲苯混合物萃取分离的效果,以萃取选择性、分配系数和萃取性能指数作为评价指标优选出1-丁基-2,3-二甲基咪唑四氯化铁([Bm₂im][FeCl₄])萃取剂。对于中低浓度芳烃体系(<33%),在30℃、溶剂质量比为4时,邻二甲苯萃取选择性在45以上,分配系数在0.38~0.40,萃取性能指数在18以上,单次萃取脱芳率可达60%以上。相比传统的环丁砜萃取剂,[Bm₂im][FeCl₄]萃取剂可以使体系具有更大的两相区,易于正辛烷/邻二甲苯的分离。利用量子化学软件探究[Bm₂im][FeCl₄]与正辛烷/邻二甲苯的弱相互作用,并计算其结合能,解释离子液体高选择性萃取邻二甲苯的原因。     

Ionic Liquid (IL) Cation and Anion Structural Effects on Metal Ion Extraction into Quaternary Ammonium-based ILs

Numerous factors have previously been shown to influence the mode of extraction of alkali and alkaline earth cations from an acidic aqueous phase into 1, 3-dialkylimidazolium-based ionic liquids (ILs) by a crown ether, among them the hydrophobicity of both the IL anion and cation. To determine if this observation is “generic” and thus, could provide the basis for guidelines for the rational design of ILs to be used as solvents in metal ion extraction, other families of ILs must be studied. A series of quaternary ammonium-based ILs have therefore been examined as solvents for the extraction of various metal ions from acidic nitrate- and chloride-containing aqueous phases by dicyclohexano-18-crown-6 (DCH18C6). Although the overall metal ion extraction behavior in these systems is similar to that observed for 1, 3-dialkylimidazolium-based ILs, significant differences in metal ion separation factors (e.g., α_Sr/Na) are observed under certain conditions, differences that may be sufficient to influence the choice of IL in separations applications.     

EXTRACTION OF STOONTIUM FROM NITRIC ACID SOLUTIONS USING DICYCLOHEXANO-18-CROWN-5 AND ITS DERIVATIVES

Dicyclohexano-18-Crown-6 (DCH18C6)and its dimethyl and di-t-butyl derivatives have been evaluated as extractants for Sr (II) from nitric acid media. As with DCH18C6, a correlation is observed between the extraction of strontium nitrate by the di-t-butyl compound dissolved in a variety of oxygenated, aliphatic solvents and the concentration of water in the organic phase. Comparison of the extractant dependencies of the three compounds using n-octanol as the diluent shows that the expected first power dependence of the strontium distribution ratio (Dsr) on crown concentration is observed only for the di-t-butyl derivative. DCH18C6 shows a marked deviation from first power dependence at crown concentrations greater -0.01 M. Dsr acid dependencies for DCHl8C6 and the di-t-butyl derivative do not exhibit the decrease in strontium distribution ratios at high acidities observed for DCH18C6 in chlorinated hydrocarbons.     

Ionic liquid-based salting-out extraction of bio-chemicals

Ionic liquids (ILs) are known as green solvents, and have been widely used in the dissolution and transformation of biopolymers, the extraction of bioactive compounds and metal ions, and the capture of SO₂ or CO₂. However, less attention was given to the separation of bio-based chemicals, such as diols and organic acids. Bio-based chemicals can be efficiently separated by organic solvent-based salting-out extraction (SOE) from fermentation broths, while organic solvents are normally unfriendly to environment and process safety in commercialized production due to their toxicity or/and flammability. In recent years, the IL-based SOE system has been explored in the separation of bio-based chemicals as an alternative of organic solvent-based SOE system. In this review, the progress of IL-based SOE of biobased chemicals has been summarized, including the effect of ILs structure on the formation of aqueous two phases, and the influences of ILs structure and concentration, temperature and pH on the partition behaviors of target products and ILs as well as removal of impurities. Most of bio-based chemicals could be distributed into the IL-rich phase with high recovery, while the partition behaviors of bio-based chemicals are sometimes different from that in organic solvent-based SOE systems. Although the results of ILbased SOE are promising, further studies are still required in the increased selectivity of target products over by-products, recovery and recycling of ILs, and the separation between ILs and bio-based chemicals. Additionally, three kinds of integrated bioprocesses would be developed on basis of utilization of ILs as extractant for SOE, catalyst for condensation reaction and solvent for pretreatment of lignocellulose.     

Application of silver-based dihydric alcohol to the extraction of methyl linolenate with high extractability and stability replacing ionic liquids

A novel silver-based dihydric alcohol extractant was substituted for ionic liquids to enrich methyl linolenate (C18-3) from tallow seed oil methyl ester in this study. The interactions among dihydric alcohol, Ag(I) and C18-3 were explored by FT-IR spectroscopy. The effects of dihydric alcohol structure, carrier Ag (I) concentration, temperature and initial feed concentration on extraction yield and selectivity were reported. The good extraction performance was achieved by 1,4-butanediol containing AgBF₄. The complexation of Ag (I) with C18-3 was dominant in extraction operation rather than physical partition. Furthermore, a multi-step reverse extraction method was proposed to obtain C18-3 product and regenerate the extractant. 1-Hexene as the stripping phase can facilitate C18-3 reverse extraction. The content of C18-3 in the product was up to 93.36%, and the yield was 73.76%. This work opened a new route for the utilization of the dihydric alcohol properties to manipulate the carrier efficiency for extracting unsaturated fatty acid methyl esters at a lower cost.     

Extraction of zinc(II) from ammoniacal solution into hydrophobic ionic liquids

BACKGROUND: Separation and recovery of zinc from ammoniacal solutions with solvent extraction is very important in the hydrometallurgical industry. Ionic liquids (ILs) have considerable potential for the separation of metal ions. The extraction behaviour of zinc from ammoniacal solution into three hydrophobic ILs was investigated using β‐diketone as the extractant. RESULTS: The extraction efficiency of zinc for three ILs reached a maximum at pH 7.5 and subsequently decreased with increase of pH and it also decreases with increase of the total ammonia concentration. The overall extraction process is exothermic. The extractability decreases in the IL order: [BMIM]NTf₂ > [OMIM]PF₆ > [OMIM]NTf₂. The results of X‐ray absorption spectra indicate that the coordination number of the extracted zinc complexes decreases with increase in the hydrophobicity of the ILs. The results of five recycling experiments indicate that the three hydrophobic ILs are more stable than [BMIM]PF₆ for the extraction of zinc in ammoniacal solutions. CONCLUSION: Hydrophobic ILs combined with β‐diketone can be used to extract zinc from ammoniacal solutions. The extraction of zinc is dependent on the zinc species in ammoniacal solutions and the hydrophobicity of ILs. Moreover, the latter affects both the extractability of extraction systems and the structure of the extracted complexes. © 2012 Society of Chemical Industry     

Partition Behavior of Drug Molecules in Cholinium-Based Ionic Liquids

In this paper, a series of ionic liquids (ILs) contains cholinium as cations were prepared. These ILs were used as extractants to separate some model drug molecules. The partition coefficients of these drug molecules between ILs and aqueous solutions were determined. Furthermore, the influence of different extraction parameters was investigated: volume ratio, equilibrium time, pH values, temperature, and ILs structure. It is shown that these ILs are highly effective materials for the extraction of drug molecules. The results imply that these ILs may have potential in drug extraction or separation as a new type of media.     

Extraction of strontium ion from sea water by contained liquid membrane permeator

To develop a liquid membrane permeator that extracts strontium ion from sea water effectively and continuously, we investigated the extraction of strontium ion from artificial and natural sea water in a contained liquid membrane permeator. The permeator consists of a liquid membrane and two cells for aqueous solutions. The liquid membrane containing D₂EHPA(di-2-ethylhexyl-phosphoric acid) and DCH18C6(dicyclohexano-18-crown-6) is trapped between two hydrophobic microporous polyethylene films and separates sea water and the 0.2 M H₂SO₄ aqueous stripping solution. The effects of various operating parameters on the extraction of strontium ion were experimentally examined. The extractant of DCH18C6 -D₂EHPA mixture in kerosene had a synergistic effect on the extraction of strontium ion. The permeator extracted strontium ion from sea water effectively and continuously with long membrane lifetime.     

Separation of m-cresol from aromatic hydrocarbon and alkane using ionic liquids via hydrogen bond interaction

Low temperature coal tar contained a large amount of phenols, aromatic hydrocarbons and alkanes; the separation of phenols from coal tar has a great significance to the deep processing of coal tar. In this work, the separation of m-cresol from cumene and n-heptane by liquid–liquid extraction using ionic liquids (ILs) as extractants was studied. The suitable ILs were screened by conductor-like screening model for real solvents (COSMO-RS) model and the liquid–liquid phase equilibrium (LLE) experiments were to verify the accuracy of the screening results. The extraction conditions such as extraction time, extraction temperature and mass ratio of ILs to model oils were evaluated. An internal mechanism of the m-cresol extract by ILs was revealed by COSMO-RS calculation and FT-IR. The results showed that the selected ILs can extract m-cresol effectively from cumene and n-heptane, 1-ethyl-3-methylimidazolium acetate (emimCH₃COO) was the best extraction solvent. A hydrogen bond between anion of ILs and phenolic hydroxyl groups was observed. M-cresol in model oils could be extracted with extraction efficiencies up to 98.85% at an emimCH₃COO: model oils mass ratio of 0.5 and 298.15 K, emimCH₃COO could be regenerated and reused for 4 cycles without obvious decreases in extraction efficiency and extractant mass.     

USE OF CROWN ETHERS AS SYNERGISTS IN THE SOLVENT EXTRACTION Of TRIVALENT ACTINIDES AND LANTHANIDES BY 1—PHENYL—3–METHYL—4 TRIFLUOROACETYL PYRAZOLONE—5

The synergistic extraction of trivalent Am, Cm, Cf and Eu with mixtures of 1—phenyl—3—methyl 1—4— trifluoroacetyl pyrazolone—5 ( HPMTFP) and a crown ether dicyclohexano—18—crown—6 (DCH18C6) or monobenzo—15—crown—5 ( B15C5) has been studied in chloroform. With DCH18C6 the synergistic species extracted are M(PMTFP)3 (HPMTFP) (DCH18C6) where N = Am, Cm and Eu and Cf ( PMTFP)3. (DCH18C6) whereas with B15C5 the species are M( PMTFP) 3.n( B15C5), n being 1 or 2 for all these metal ions. The possibility of high coordination numbere for theee metal ions in the above syeteme and the probable reaeone for the anbormel order of synergistic constants namely K2?81 have been discussed.     

Ionic Liquids as Extraction Solvents: Where do We Stand?

Abstract

The unique physicochemical properties of ionic liquids (ILs) and the relative ease with which these properties can be fine‐tuned by altering the cationic or anionic moieties comprising the IL have led to intense interest in their use as alternatives to conventional organic solvents in a wide range of synthetic, catalytic, and electrochemical applications. Recent work by a number of investigators has been directed at the application of ionic liquids in various separation processes, among them the liquid‐liquid extraction of metal ions. Although certain IL‐extractant combinations have been shown to yield metal ion extraction efficiencies far greater than those obtained with molecular organic solvents, other work suggests that the utility of ILs may be limited by solubilization losses and difficulty in recovering extracted metal ions. In this report, recent efforts to overcome these limitations are described, and progress both in achieving an improved understanding of the fundamental aspects of metal ion transfer into ILs and in devising viable IL‐based systems for metal ion separation is detailed. In addition, areas upon which future research efforts might profitably be focused are identified.