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。     

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.     

基于离子液体原位泡腾萃取法在丹参及西洋参克百威残留分析中的应用

本研究建立了一种新颖的基于酸性离子液体的原位泡腾萃取技术的前处理方法。酸性离子液体1-丁基-3-甲基咪唑硫酸氢盐呈酸性,能与碳酸氢盐反应产生二氧化碳,起到泡腾萃取的效果,它还能与六氟磷酸铵发生离子交换作用而置换成疏水性离子液体1-丁基-3-甲基咪唑六氟磷酸盐,使其与水相分离,通过离心获取萃取相,最后通过高效液相色谱仪测定萃取相中农药的含量。考察了酸性离子液体、碳酸氢钠和氯化钠用量对萃取效率的影响,最终所得最佳条件为200 mg酸性离子液体、0.4 g碳酸氢钠和1.0 g氯化钠。在最优条件下,克百威的线性范围为0.3～4.0μg/mL,日内和日间的相对偏差(RSD)为4.6%和10.2%,丹参和西洋参在4.0μg/mL加标水平下,加标回收率为94.7%(西洋参)和74.6%(丹参),将此方法可用于不同基质中药材和饮片中农药残留的处理。     

离子液体体系用于盐湖卤水提取锂

3种咪唑类离子液体:1-丁基-3-甲基咪唑六氟磷酸盐([C₄mim][PF₆])、1-己基-3-甲基咪唑六氟磷酸盐([C₆mim][PF₆])、1-辛基-3-甲基咪唑六氟磷酸盐([C₈mim][PF₆])被作为绿色溶剂用于盐湖卤水分离镁锂, 建立了以离子液体(ILs)、磷酸三丁酯(TBP)分别为萃取介质和萃取剂的盐湖卤水锂萃取体系, 并与使用传统有机溶剂磺化煤油和氯仿的萃取效果进行了对比。研究发现, 该离子液体体系较使用传统挥发性有机溶剂的萃取体系有更高的萃取率。锂的萃取率随离子液体中烷基碳原子数的减小而增加。详细考察了溶液pH、离子液体浓度、相比对萃取效率的影响, 获得了离子液体体系萃取的最优条件。在最佳萃取条件下, 3种离子液体体系对锂的单级萃取效率均高于80%, 分离系数最高达到100以上。机理研究表明:离子液体体系是以阳离子交换实现对锂的萃取, Li⁺与TBP形成[Li·2TBP]⁺络合物进入有机相。     

1-丁基-3-甲基咪唑六氟磷酸盐离子液体合成

按照两步法合成了离子液体1-丁基-3-甲基咪唑六氟磷酸盐([Bmim]PF6),探讨了时间、温度、溶剂、反应物配比等对中间体1-丁基-3-甲基咪唑溴盐([Bmim]Br)以及离子液体[Bmim]PF6产率的影响。结果表明,反应物配比为(1∶1.1)~(1∶2),温度70℃,反应30 h,中间体产率为95.91%;中间体中加入等摩尔KPF6,25℃下反应10 h后,离子液体产率为97.26%。     

咪唑类[PF_6]^-型离子液体萃取苯胺

研究了以咪唑类[PF6]-型室温离子液体1-丁基-3-甲基咪唑六氟磷酸盐（[Bmim][PF6]）、1-己基-3-甲基咪唑六氟磷酸盐（[Hmim][PF6]）和1-辛基-3-甲基咪唑六氟磷酸盐（[Omim][PF6]）对苯胺水溶液的萃取平衡。实验结果表明：pH值对分配系数的影响很大,在碱性条件下,分配系数较高;萃取过程属于吸热过程;经过四级错流萃取,废水可达到排放标准,萃取相中的苯胺回收率在90%左右,离子液体回收率〉90%,离子液体可以循环利用。     

咪唑类离子液体的合成和光谱表征

以N-甲基咪唑为原料合成了离子液体氯化1-丁基-3-甲基咪唑盐([BMIm]Cl)、1-丁基-3-甲基咪唑氟硼酸盐([BMIm]BF4)、1-丁基-3-甲基咪唑六氟磷酸盐([BMIm]PF6),并对合成的产物作了紫外光谱、红外光谱、核磁共振的结构表征。     

咪唑类离子液体高效吸收二氯甲烷

合成了一系列常规离子液体1-丁基-3-甲基咪唑四氟硼酸盐([Bmim][BF4])、1-丁基-3-甲基咪唑六氟磷酸盐([Bmim][PF6])、1-丁基-3-甲基咪唑双三氟甲磺酰亚胺盐([Bmim][NTf2])、1-丁基-3-甲基咪唑双氰胺盐([Bmim][DCA])、1-丁基-3-甲基咪唑硫氰酸盐([Bmim][SCN])、1-乙基-3-甲基咪唑硫氰酸盐([Emim][SCN])和N-丁基吡啶硫氰酸盐([BPy][SCN]),用智能重量分析仪(IGA)测定不同温度和分压下离子液体吸收二氯甲烷(DCM)的容量。结果表明,[Bmim][SCN]具有最高的二氯甲烷吸收容量(1.46 g/g, 303.15 K, 60 kPa),5次循环后吸收能力无明显下降,[Bmim][SCN]基本可完全再生,能循环使用。量化计算结果表明[SCN]?可与二氯甲烷形成氢键,增强其对二氯甲烷的吸收能力。     

疏水性离子液体为溶剂对Co2+和Cd2+废水的萃取性能

研究了疏水性离子液体[Bmim]PF6(1-丁基-3-甲基咪唑六氟磷酸盐)、[Hmim]PF6(1-己基-3-甲基咪唑六氟磷酸盐)和[Omim]PF6(1-辛基-3-甲基咪唑六氟磷酸盐)对Co2+和Cd2+的萃取性能. 结果表明,未加入螯合剂时,离子液体对Co2+和Cd2+的萃取率都很低. 螯合剂的加入大大提高了离子液体对重金属离子的萃取性能,Co2+和Cd2+的萃取率分别由原来的2.06%和1.82%提高到96.37%和93.68%. 不同螯合剂对离子液体萃取Co2+和Cd2+有一定的影响. 离子液体碳链长度的增加有利于Co2+和Cd2+的萃取. 与传统有机溶剂相似,离子液体萃取重金属离子过程中具有很强的pH摆动效应,当pH<2时,Co2+和Cd2+的萃取率几乎为0,而当pH>6时,Co2+和Cd2+的萃取率均大于90%. 运用萃取过程中的pH摆动效应对Cd2+进行反萃取,实现了离子液体的回用.     

咪唑类离子液体的合成及其对氯苯的吸收-解吸性能研究

以溴代正丁烷、Ⅳ甲基咪唑为原料,合成了咪唑类离子液体1丁基3甲基咪唑六氟磷酸盐([Bmim] PF6)和1-丁基-3-甲基咪唑四氟硼酸盐([Bmim] BF4),通过红外光谱和核磁共振氢谱表征了离子液体结构;以离子液体为吸收剂进行氯苯气体吸收实验,考察了吸收温度、吸收时间、进气氯苯浓度等对离子液体吸收氯苯气体性能的影响...     

脱芳复合萃取剂的研究进展

复合萃取剂包括传统复合溶剂和新型复合溶剂。前者是有机溶剂与有机溶剂或无机盐的复配,后者则是不同种类的离子液体复配,它们不仅具有对芳烃的溶解性好、选择性高的优点,而且萃取后,萃余油的收率相对较高,已经成为继单一萃取剂用于油品（石脑油、重整汽油和模拟油等）脱芳烃研究之后又一新的研究热点。本文综述了国内外脱芳烃复合萃取剂的研究进展,重点介绍了两类复合萃取剂（萃取剂与醇类、胺类溶剂或无机盐复配和离子液体复配）在油品萃取脱芳烃中的应用;根据复合萃取剂中助萃取剂的种类不同,对用于萃取脱芳烃的复合萃取剂进行了分类总结;介绍了不同种类的萃取剂复配与不同种类的离子液体复配的研究进展;最后指出复合萃取剂在分离芳烃应用中具有选择性高、分配系数高、操作工艺简单有效且成本低廉等优点,是工业上萃取脱芳烃今后的发展趋势。     

Dearomatization of pyrolysis gasoline with an ionic liquid mixture: Experimental study and process simulation

The pyrolysis gasoline is the main source of benzene, toluene, and xylenes. The dearomatization of this stream is currently performed by liquid – liquid extraction using sulfolane. However, the sulfolane process has high operating costs that could be minimized by employing ionic liquids as solvents because of their non‐volatile character. In this work, we proposed a novel process to perform the dearomatization of pyrolysis gasoline using a binary mixture of 1‐ethyl‐3‐methylimidazolium tricyanomethanide ([emim][TCM]) and 1‐ethyl‐4‐methylpyridinium bis(trifluoromethylsulfonyl)imide ([4empy][Tf₂N]) ILs. The composition in the IL mixture was optimized considering their extractive and thermophysical properties. The Kremser method was applied using the experimental data to determine the number of equilibrium stages in the liquid – liquid extractor which provides the same extraction yields of aromatics using the IL mixture that those of the sulfolane process. The recovery section was designed and simulated from the experimental vapor – liquid equilibrium between the hydrocarbons and the IL mixture. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4054–4065, 2017     

Purification of ionic liquids by supercritical CO2 monitored by infrared spectroscopy

Transmission infrared and Attenuated Total Reflection (ATR) in situ infrared spectroscopies were combined for the time-resolved monitoring of both liquid and supercritical phases during extraction of water and other impurities from ionic liquids with supercritical carbon dioxide (scCO₂). Cleaning and drying by scCO₂ at 100 bar and 40 °C proved to be efficient for all ionic liquids tested, including 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF₄]), 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF₆]), and 1-butyl-3-methylimidazolium trifluoromethansulfonate ([bmim][TfO] or [bmim] triflate). Despite the moderate solubility of water in scCO₂ compared to other classical solvents, the amount of water decreased continuously during the drying. The extraction could be followed by simple transmission IR spectroscopy of the supercritical phase. During the extraction, organic impurities and water were removed rapidly from the ionic liquid phase as scCO₂ improved the transport properties in the ionic liquids.     

疏水性离子液体用于萃取酚类物质

测定了苯酚、苯基酚、苯二酚等几种不同取代基的酚类物质在疏水性离子液体[bmim]PF6(1-丁基-3-甲基咪唑六氟磷酸盐)和[dmim]PF6(1-癸基-3-甲基咪唑六氟磷酸盐)与水两相中的分配系数. 实验结果表明,萃取过程很快可以达到平衡. 与传统有机溶剂相比,分配系数处在同一个数量级. 分配系数随温度升高而降低,离子液体对不同取代基的酚类萃取能力有很大差异,咪唑基团上取代烷基链的长度对不同酚类物质的分配系数有很大影响,因此可以通过调节离子液体结构使其适用于不同成分的含酚废水.     

Development of energy-optimum aromatic extraction processes using ionic liquid [EMIM][NTf2]

There is industrial incentive to extract aromatics from ethylene cracker feeds, but the conventional sulfolane solvent was found not economical by Meindersma and coworkers. Ionic liquids (ILs) have long been considered alternative aromatic extraction solvents. This work develops energy-optimum aromatic extraction processes for an ethylene cracker feed using IL solvents. We avoid pitfalls of using simplified feeds and a priori thermodynamic property estimates, with the largest set of experimentally regressed UNIQUAC binary parameters for the IL, 1-ethyl-3-methylimidazolium bis([trifluoromethyl]sulfonyl)imide ([EMIM][NTf2]). We screen process energy and operating conditions for [EMIM][NTf2] and sulfolane at varying aromatic feed contents and find [EMIM][NTf2] favorable at low aromatic feed contents. Adding light and heavy components of the ethylene cracker feed necessitates process modifications. Our novel steam-assisted extractive distillation developed for [EMIM][NTf2] is also suitable for sulfolane. We show that the [EMIM][NTf2] solvent can reduce 10.7% of energy consumption compared to sulfolane using the same novel process.     

微波辅助离子液体制备及催化降解聚酯

采用微波辅助离子交换法,以氯化1-丁基-3-甲基咪唑([Bmim]Cl)和氯化锌为原料,合成了1-丁基-3-甲基咪唑氯锌酸盐离子液体,并考察了合成过程中溶剂对离子液体合成的影响。进一步以制备的离子液体为催化剂,乙二醇为溶剂,采用微波辅助乙二醇醇解聚对苯二甲酸乙二醇酯(PET)。以对苯二甲酸的回收量为指标,分别考察了离子液体用量、反应温度、时间以及溶剂用量对PET降解反应的影响。结果表明,采用微波辅助离子交换法在30 min内即可合成得到相应的离子液体,以二氧六环为溶剂时,3种产物的产率均高于90%。在微波加热的条件下,离子液体[Bmim][Zn2Cl5]对PET的乙二醇醇解反应具有较好的催化性能,对苯二甲酸的产率超过20%。     

Ionic liquids as co-solvents for zwitterionic copolymers and the preparation of poly(vinylidene fluoride) blend membranes with dominated β-phase crystals

A new series of green solvents that constituted with ionic liquids (ILs) and dimethyl acetamide (DMAc) were developed as good solvents for zwitterionic copolymers, and the dissolutions of amphiphilic copolymers carrying carboxylbetaine and sulfonatebetaine in these new solvents were studied. It was determined that the commonly found ILs such as 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF₄), 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM]PF₆) and many others were all effective co-solvents for zwitterionic copolymer with carboxylbetaine groups. However, the 1-methylimidazolium trifluoromethanesulfonic ([MIM]CF₃SO₃) instead of the [BMIM]BF₄ was proved as an effective co-solvent for the copolymer carrying sulfonatebetaine units. These newly designed mix-solvents were also good solvents for poly(vinylidene fluoride) (PVDF) and their influences on the crystallization as well as the formation of PVDF membranes were investigated. Our results had demonstrated that blend membranes with zwitterionic additives could be facilely prepared with many new solvent candidates.     

Extraction Behavior of Cu(II) Ion From Chloride Medium to the Hydrophobic Ionic Liquids Using 1,10-Phenanthroline

The study of liquid-liquid extraction of Cu(II) ion was carried out by using a series of hydrophobic ionic liquids; 1-butyl-3-methylimidazolium hexafluorophosphate ([C₄mimPF₆]), 1-hexyl-3-methylimidazolium hexafluorophospahate ([C₆mimPF₆]), 1-butyl-3-methylimidazolium bistrifluoromethylsulfonyl imide ([C₄mimNTf₂]) and 1-hexyl-3-methylimidazolium bistrifluoromethylsulfonyl imide ([C₆mimNTf₂]) as extraction phase. Cu(II) prefer to extract into [C₄mimPF₆] which is the less hydrophobic of ionic liquids. The extraction behavior of Cu(II) ion depends on the type of counterion and the extraction of Cu(II) ion in ionic liquid system proceeds via similar mechanism with a molecular organic solvent. From these results, it was proposed that the extraction of Cu complexes from chloride medium proceeds through ion pair mechanism.     

两种咪唑型离子液体对纤维素的溶解及纺丝性能的比较

以1-乙基-3-甲基咪唑醋酸盐（[EMIM]Ac）和1-丁基-3-甲基咪唑氯盐（[BMIM]CI）两种咪唑型离子液体为溶剂,研究比较了它们对纤维素的溶解性能及其溶液的纺丝加工性能。结果发现：两种离子液体均能在一定条件下溶解纤维素,但[EMIM]Ac较[BMIM]Cl对纤维素具有更低的溶解温度和更快的溶解速率。从流变分析还发现：纤维素/[EMIM]Ac溶液与纤维素/[BMIMCl溶液均为切力变稀流体,相同条件下纤维素/[EMIM]Ac溶液的黏度远低于纤维素/[BMIM]Cl溶液,使其可在相对低的温度下纺丝。此外,GPC分析结果表明：纤维素在用[EMIM]Ac溶解及纺丝过程中降解程度较小,而用[BMIM]Cl进行溶解纺丝时,降解作用则较明显。对纤维结构与力学性能的分析结果进一步表明：与相同喷头拉伸比下制得的[EMIM]Ac法再生纤维素纤维相比,[BMIM]Cl法再生纤维素纤维的聚集态结构相对较完善,结晶度与取向度更高些,从而使其力学性能也相对较好。