含氰基离子液体的物理性能及其对SO_2的吸收性能

对两种阴离子含氰基的离子液体1-乙基-3-甲基咪唑硫氰酸盐([Emim][SCN])、1-丁基-3-甲基咪唑硫氰酸盐([Bmim][SCN])的密度、粘度及热稳定性等物理性质进行了研究,探讨了离子液体的分子体积V_m、标准熵S~0、晶格能U_(POT)等热力学性能。同时对两种离子液体的脱硫性能进行了研究。结果表明,两种离子液体的热稳定性较高,能够适用于烟气脱硫应用。两种离子液体均表现出良好的脱硫性能,20℃条件下,1 mol[Bmim][SCN]可吸收3.04 mol SO_2,且[Emim][SCN]、[Bmim][SCN]循环脱硫5次脱硫性不变。通过核磁共振H谱和红外光谱对两种离子液体的脱硫机理进行研究,发现离子液体和SO_2的结合主要为物理作用。     

含氰基离子液体的物理性能及其对SO_2的吸收性能

对两种阴离子含氰基的离子液体1-乙基-3-甲基咪唑硫氰酸盐([Emim][SCN])、1-丁基-3-甲基咪唑硫氰酸盐([Bmim][SCN])的密度、粘度及热稳定性等物理性质进行了研究,探讨了离子液体的分子体积V_m、标准熵S⁰、晶格能U_(POT)等热力学性能。同时对两种离子液体的脱硫性能进行了研究。结果表明,两种离子液体的热稳定性较高,能够适用于烟气脱硫应用。两种离子液体均表现出良好的脱硫性能,20℃条件下,1 mol[Bmim][SCN]可吸收3.04 mol SO_2,且[Emim][SCN]、[Bmim][SCN]循环脱硫5次脱硫性不变。通过核磁共振H谱和红外光谱对两种离子液体的脱硫机理进行研究,发现离子液体和SO_2的结合主要为物理作用。     

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...     

低黏二氰胺类离子液体乙烯汽液相平衡研究

从工业废气中回收分离乙烯(C_2H_4)具有重要意义,选用了三种低黏度二氰胺类离子液体,分别测定了293.15～333.15 K下其密度、黏度等物化性质,研究了其对乙烯(C_2H_4)吸收性能。采用非随机(局部)双液体模型(NRTL)关联了三种二元体系溶解度数据,实验值与计算值的平均相对偏差均小于3%。结果表明,低黏度二氰胺类离子液体对C_2H_4气体吸收性能良好,其中阳离子侧链长度增加和羟基功能团引入可增强对C_2H_4溶解度。同时,离子液体1-丁基-3-甲基咪唑二氰胺盐([Bmim][DCN])经过3次的吸收解吸循环,仍可以保持较好的C_2H_4吸收性能,表明该离子液体循环稳定性好,而1-丁基-3-甲基咪唑二氰胺盐([Bmim][DCN])对乙烯吸收量较高,具有作为C_2H_4吸收剂的潜力。     

咪唑类双氰胺根离子液体的合成与表征

合成了两种典型的咪唑类双氰胺根离子液体,1-丁基-3-甲基咪唑双氰胺盐([Bmim][N(CN)2])和1-烯丙基-3-甲基咪唑双氰胺盐([Amim][N(CN)2])。通过元素分析、核磁共振和红外光谱对产物的组成和结构进行了表征。结果表明,获得的物质即为目标双氰胺根离子液体,且纯度较高。这为今后有关研究工作的发展提供了科学依据。     

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.     

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%。     

[Bmim][PF6]高效吸收二氯甲烷及流程模拟

采用智能重量吸附仪测量了不同温度、压力下二氯甲烷(CH2Cl2)在离子液体1-丁基-3-甲基咪唑六氟磷酸盐([Bmim][PF6])中的溶解度,用NRTL方程建立了离子液体?二氯甲烷体系的气液平衡模型,拟合得到二元交互作用参数,计算所得的二氯甲烷溶解度与实验数据吻合良好,平均相对误差为3.16%. 构建了离子液体处理含二氯甲烷尾气及资源回收利用的常压吸收?减压闪蒸解吸工艺和模型,模型适用范围为温度278.15~308.15 K,压力0~0.1 MPa. 对吸收塔进行了模拟和灵敏度分析,获得了常温常压吸收条件下的最佳操作工艺参数.     

1-丁基-3-甲基咪唑表面活性离子液体的界面膨胀流变行为研究

研究了1-丁基-3-甲基咪唑十二烷基硫酸盐([bmim][DS])和1-丁基-3-甲基咪唑二(2-乙基己基)磺基琥珀酸酯盐([bmin][AOT]两种表面活性离子液体在正庚烷/水界面的动态界面张力和膨胀特性。比较了[bmim][DS]或[bmin][AOT]和传统表面活性剂十二烷基硫酸钠(SDS)或二(2-乙基己基)磺基琥珀酸酯钠(Na[AOT])之间的膨胀弹性,并且考察了1-丁基-3-甲基咪唑阳离子之间静电相互作用对界面膜特性的影响。另外,通过对比[bmim][DS]和[bmim][AOT]在不同浓度下的膨胀弹性,验证了烷基链数量的改变对界面膨胀流变行为的影响。     

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。     

Insight into the behavior at the hygroscopicity and interface of the hydrophobic imidazolium-based ionic liquids

How to completely remove the water from ionic liquids(ILs) is difficult for researchers because of the hygroscopicity of ILs. In order to study the hygroscopicity of ILs, two kinds of ILs, 1-Butyl-3-methylimidazolium hexafluorophosphate([Bmim][PF_6]) and 1-Butyl-3-methylimidazolium Bis(trifluoromethanesulfonyl)([Bmim][NTf_2]) were investigated by molecular dynamics simulations. Although[Bmim][PF_6] and [Bmim][NTf_2] are hydrophobic, both of the ILs could absorb water molecules from the vapor. In this work, the process of absorbing water from the vapor phase was studied, and the water molecules could disperse into the IL. Aggregation was observed with increasing the water concentration.Although the absorbed water increases obviously, the amount of free water and small cluster in the ILs does not change significantly and always stays at a certain level. The amount of free water and small cluster in [Bmim][PF_6] is more than that in [Bmim][NTf_2], which is consistent with their hydrophobicity. In addition, the liquid-vacuum and liquid–liquid interfaces of the ILs were simulated and analyzed in detail.The number density distribution and angle distribution indicated that [Bmim]+cations arrangement regularly at the IL-vacuum interface. The butyl chain point to the vacuum, while the imidazlium ring is close to the IL phase region and perpendicular to the interface. While at the IL-water interface, the cations and anions are disordered.     

Removal of carbon dioxide from flue gases in packed column using ionic liquids

The study of CO₂ absorption in ionic liquids (ILs): [Emim] [Ac], [Bmim] [Ac] in a packed column is presented. The influence of mass transfer resistances, initial CO₂ concentration, absorption temperature and 2, 5, 10% wt. water addition on CO₂ removal efficiency was investigated. The resistance in series model and estimated values of enhancement factor were used to predict with good accuracy mass fluxes of absorbed carbon dioxide for both ILs. The CO₂ absorption efficiency in packed column depends on temperature and initial CO₂ concentration. The addition of small amounts of water to [Emim][Ac] is of minor effect on CO₂ absorption.     

SO2 Absorption/Desorption Characteristics of Two Novel Phosphate Ionic Liquids

Two kinds of phosphate ionic liquids were synthesized and their SO₂ absorption performance was investigated. It was found that both ionic liquids could readily absorb SO₂, and the absorption capacity could reach 2.8 and 2.7 mol SO₂ per mole ILs, respectively, at ambient temperature and under normal pressure. Moreover, the cycle of SO₂ absorption and desorption from ionic liquids was repeated for four times and no change in the absorption capacity was observed. FT-IR spectrum and ¹H NMR were used to characterize the microstructure of SO₂-absorbed ILs and ILs, analysis showed that both ionic liquids absorbed SO₂ purely by physical absorption. Comparing with the previous reported ionic liquids such as [Bmim][PF6] and [Emim][BF4], the synthesized ionic liquids showed higher absorption capacity, due to the anion based phosphate (O?P?O) with the free electrons on the oxygen interacting with the Lewis acidic sulfur of SO₂, and then showing a great affinity for SO₂.     

咪唑类离子液体混合物用于二氧化硫高效吸收

开发易制备、价格便宜、面向SO₂气体高效分离的离子液体（ILs），是当前ILs从实验探索迈向工业应用的难点与重大挑战。合成了不同摩尔比（3∶1、2∶1、1∶1、1∶2和1∶3）的1-乙基-3-甲基咪唑氯盐（[Emim][Cl]）和1-乙基-3-甲基咪唑乙酸盐（[Emim][OAc]）的离子液体混合物[Emim][Cl]_x[OAc]_1-x， 在测定其密度、黏度、热稳定性等基本物性数据的基础上，研究了[Emim][Cl]_x[OAc]_1-x混合物在不同温度和SO₂分压下的SO₂吸收能力。结果表明，[Emim][Cl]_x[OAc]_1-x能够有效地捕获SO₂。[Emim][Cl]与[Emim][OAc]之间存在协同促进作用，有利于实现SO₂高效吸收。[Emim][Cl]_0.33[OAc]_0.66混合液在1.0和0.2 atm（1 atm=101325 Pa）下捕获SO₂量分别为（1.34±0.08）和（0.74±0.05） g/g，与现有结果相比，混合物在SO₂捕获方面有明显优势。此外，这些离子液体混合物对二氧化硫的吸收和解吸具有良好的可逆性。     

High capacity absorption of SO2 using imidazole ionic liquid mixtures

The capture of sulfur dioxide (SO₂) with readily available and cost-effective ionic liquids (ILs) is one of the challenges for the application of ILs. Here, we synthesized the ILs mixtures with different molar ratios (3∶1, 2∶1, 1∶1, 1∶2, and 3∶1) of 1-ethyl-3-methylimidazolium chloride ([Emim][Cl]) and 1-ethyl-3-methylimidazolium acetate ([Emim][OAc]) to study their SO₂ absorption capacities. The SO₂ solubilities in these mixtures were investigated under different conditions. The SO₂ absorption capacities of [Emim][Cl]_x[OAc]_1-x at different temperatures and SO₂ partial pressure were measured. The results show that ILs can effectively capture SO₂. There exists a synergistic promotion effect between [Emim][Cl] and [Emim][OAc], resulting in quite high SO₂ absorption capacity. The [Emim][Cl]_0.33[OAc]_0.66 mixture can capture SO₂ (1.34±0.08) and (0.74±0.05) g/g at 1.0 and 0.2 atm(1 atm=101325 Pa), respectively. Comparing with the reported data, [Emim][Cl]_x[OAc]_1-x mixtures show obvious advantage for SO₂ capture. In addition, these ionic liquid mixtures have good reversibility for the absorption and desorption of sulfur dioxide.     

COSMO-RS based predictions for the desulphurization of diesel oil using ionic liquids: Effect of cation and anion combination

Ionic Liquids ILs provide an important alternative in removing aromatic sulphur compounds by Liquid-Liquid Extraction (LLE). A total of 28 anions and 6 cations resulting in 168 possible combinations were screened via COSMO-RS (COnductor Like Screening MOdel for Real Solvents). Initially benchmarking was performed to predict the infinite dilution activity coefficients of thiophene in ionic liquids. Comparison with literature values involving 8 ILs with 20 points gave the average root mean square deviation (RMS) to be 11%. Thereafter artificial simulated diesel, aromatic sulphur compound and the cation and anion combination was used to predict the capacity (C) and selectivity (S) at infinite dilution. In general the selectivities were found to decrease in the following order: thiophene (4-24) > benzothiophene (2-12)> dibenzothiophene (1-7). The different hetero atom (N,S,O) and its location in the cation structure strongly influenced the selectivity and capacity at infinite dilution for all the three aromatic sulphur compounds. It was found that the cation without the aromatic ring combined with anions having sterical shielding effect such as [SCN], [CH₃SO₃], [CH₃COO], [Cl], and [Br] proved to be the most favourable IL for desulphurization. [EMMOR][SCN] proved to be the most viable IL for the removal of all the three aromatic sulphur compounds.     

Dissolution of antibiotics mycelium in ionic liquids: Performance and mechanism

Antibiotics mycelium, byproduct of pharmaceutical industry, contains high percentage of proteins, polysaccharides and lipids, while, the low solubility in traditional solvents limits its utilization. The dissolution process of penicillin mycelium was investigated using ionic liquids(ILs) as solvent. Quantitative correlation of solubility and ILs structure and dissolution mechanism were determined. About 91.45% of penicillin mycelium was dissolved in 1-butyl-3-methylimidazolium acetate([Bmim]Ac) under the condition of 120.0 ℃ and [Bmim]Ac/mycelium(m/m) ratio of 3.90:1. Synergistic effect of ILs and DMSO was confirmed with the DMSO/[Bmim]Ac(v/m) ratio in the range of 0.0-1.0. At 25.0 ℃, the dissolution of penicillin mycelium increased from 69.74% to94.50%, with the ratio of DMSO to [Bmim]Ac(v/m) as 1:1. The room temperature dissolution of mycelium provides a novel and energy-saving process for its high-valued utilization. The NMR and FT-IR spectra showed that hydrogen bonds are the dominant driving force for the dissolution in ILs. Quantitative study on the effects of anions and cations of ILs on dissolution using Kamlet-Taft model showed that there was a linearly positive correlation between solubility of penicillin mycelium and(3 parameter of the ILs. The solubility of mycelium increased with increasing hydrogen bond accepting ability of anions and donating ability of cations.     

Improving Physical Adsorption of CO2 by Ionic Liquids‐Loaded Mesoporous Silica

CO₂ sorption capacities of the neat and silica‐supported 1‐butyl‐3‐methylimidazolium‐based ionic liquids (ILs) were measured under atmospheric pressure. The silica‐supported ILs were synthesized by the impregnation‐vaporization method and charactrized by N₂ adsorption/desorption and thermogravimeteric analysis (TGA). Evaluation of the effects of influential factors on sorption capacity demonstrated that by increase of the temperature, flow rate, and the weight percentage of ILs in sorbents, the sorption capacity decreases. Among the sorbents, [Bmim][TfO] and SiO₂‐[Bmim][BF₄](50) had the highest capacity. By increasing the IL portion in SiO₂‐[Bmim][BF₄], the selectivity for CO₂ to CH₄ could be improved. The CO₂‐rich sorbents could be easily recycled.     

Influence of ionic liquids under controlled water activity and low halide content on lipase activity

Room-temperature ionic liquids (ILs) can be used as reaction media for nonaqueous biocatalysis. However, the purity of ILs should be considered to understand the influence of ILs on enzyme activity. The major impurities in ILs are water and halide. In the transesterification of benzyl alcohol with vinyl acetate, the optimal water activities for lipases in [Omim][Tf₂N] were similar to those in organic solvents. The chloride impurity in [Omim][Tf₂N] seriously influenced the activity of lipase. In this work, the effect of ILs on lipase activity was investigated under controlled initial water activity and low halide content. The activity of lipase was highly dependent upon the anion structure of ILs. The initial reaction rate of lipases followed the order [Tf₂N]⁻>[PF6]⁻>[TfO]⁻>[SbF₆]⁻≈[BF₄]⁻. All tested lipases showed the highest activities in ILs containing [Tf₂N] anion. Particularly, [AAIM][Tf₂N] was shown as a suitable reaction medium for biocatalysis. Lipozyme IM showed the highest activity in this IL among tested ILs. Thermal stability of lipase was also investigated. The higher thermal stability of Novozym 435 was obtained in hydrophobic and water-immiscible ILs such as [Bmim][Tf₂N], [Edmim][Tf₂N], and [Bmim][PF₆].     

Effect of small amount of water on the dynamics properties and microstructures of ionic liquids

A series of systems of 1‐butyl‐3‐methylimidazolium acetate ([Bmim][Ac]), 1‐butyl‐3‐methylimidazolium tetrafluoroborate ([Bmim][BF₄]), and 1‐butyl‐3‐methylimidazolium bis(trifluoromethylsulfonyl)imide ([Bmim][Tf₂N]) with a small amount of water were simulated. Viscosities of systems were obtained by nonequilibrium molecule dynamics simulation and the results show that the viscosities change in different ways: for [Bmim][BF₄] and [Bmim][Tf₂N], viscosities decrease rapidly in the first stage, and then decrease slowly with the increase of water content. But for [Bmim][Ac], the viscosities increase first and then decrease. The unique phenomenon of [Bmim][Ac] can be attributed to the formation of chain‐like structure of anion???water???anion???. Hydrogen bond (HB) interaction between ion pairs is weakened, but the number of HB between water and anions increases with increase of water content. Besides, the microstructures of water in ionic liquids‐water systems were compared and found that the distribution of water is more concentrated in [Bmim][Tf₂N]‐H₂O system, while it is isotropy in [Bmim][Ac]‐H₂O system. © 2016 American Institute of Chemical Engineers AIChE J, 63: 2248–2256, 2017