基于COSMO-SAC模型的分子筛选方法用于咪唑类离子液体吸收甲苯蒸气

采用基于COSMO-SAC模型的分子筛选方法,对作为甲苯蒸气吸收剂的咪唑类离子液体进行了筛选。建立了100种常见的N,N'-二烷基咪唑阳离子与阴离子构成的咪唑类离子液体的s-谱图,在此基础上计算了303.15 K下离子液体对甲苯的吸收势,并以此为热力学评价标准对吸收剂进行筛选。选取6种离子液体进行甲苯蒸气的吸收实验,通过其饱和吸收量验证此方法的可行性。研究表明,实验和分子筛选结果相吻合。利用Gaussian 09软件进行微观结构分析,计算了离子液体阳离子与甲苯的相互作用能。对进气浓度和进气速度等动力学因素的影响进行探究,在条件为303.15 K、进气浓度为10000 mg·m~(-3)、进气速度为0.05 m~3·h~(-1)情况下,离子液体对甲苯的初始吸收率高达96.2%。此外,实验验证了离子液体随着重复利用次数的增加,其吸收效果基本不变。     

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SO     

咪唑类离子液体对苯系挥发性有机物脱除性能的研究

为研究咪唑类离子液体吸收甲苯的性能,考察了甲苯体积分数、吸收温度、N₂进气速度和离子液体流量等对吸收甲苯性能的影响,并评价了离子液体的再生性能。结果表明,[Emim][Tf₂N]、[Bmim][Tf₂N]和[Omim][Tf₂N]这3种离子液体对甲苯的吸收率均在90%以上,且阳离子碳链越长,对甲苯的吸收率越高,3种离子液体对甲苯的吸收率大小为:[Omim][Tf₂N]>[Bmim][Tf₂N]>[Emim][Tf₂N]。甲苯体积分数为3 113μL/L、N₂进气速度为50 mL/min、离子液体流量为15 mL/min和吸收温度为20℃的条件下,离子液体对甲苯的吸收率最高。离子液体在140℃、5 066 Pa下干燥再生5次后性能基本稳定。     

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。     

基于COSMO-RS方法筛选离子液体用于焦油脱除

焦油的脱除是生物质气化规模化应用的难题。离子液体具有饱和蒸气压低、分子结构可设计等优势,在催化和吸收领域有广泛的应用前景,但在脱除焦油方面鲜有探索。以改进的COSMO-RS方法为基础,借助COSMOtherm软件推算离子液体对苯、甲苯、苯酚和萘等焦油模拟物的无限稀释活度系数。并进一步通过偏摩尔过量焓验证以上筛选结果。结果表明,优选的两取代基咪唑类离子液体对四种焦油模拟物的无限稀释活度系数值主要分布在0.4~1之间,预计具有良好的吸收性能。当阴离子相同时,两取代基咪唑阳离子随着R₁位置烷基侧链的增长吸收性能变好,其中[C₈MIM][NTf₂]表现出了较佳性能,吸收苯、甲苯和萘的γ^∞分别为0.95、1.24和1.36,但此时离子液体黏度较大;对于苯酚体系,[BF₄]^-阴离子性能较佳。     

咪唑类离子液体合成及其应用研究

介绍了咪唑类离子液体的一般性质和合成方法,及其作为一种新型的化学溶剂广泛应用于化学合成、分离过程和电化学等方面,具有良好的发展前景。     

咪唑类离子液体辅助溶剂萃取油砂沥青研究

采用阴离子为BF₄^-,阳离子为1-烷基-3-甲基咪唑类的离子液体（Ionic Liquids,ILs）辅助丙酮/正庚烷复合溶剂和甲苯2种溶剂萃取加拿大油砂中的沥青,考察了ILs辅助2种溶剂萃取油砂沥青过程中,ILs阳离子咪唑环一取代位上的碳链长度对沥青萃取率和固体夹带的影响。实验结果表明,随着ILs阳离子咪唑环一取代位上碳链的增长,沥青的萃取率总体逐渐降低。碳链从甲基变化到正己基,在丙酮/正庚烷复合溶剂体系中,沥青萃取率由9.29%降到8.55%;在甲苯体系中,沥青萃取率由10.05%降低到9.45%。但在2种体系中,加入碳链为正丁基的IL的沥青萃取率高于碳链为正丙基的IL。采用红外光谱对不同萃取体系中所萃出的沥青相进行分析发现,纯甲苯萃出的沥青相中检测到砂砾物质,而6种ILs辅助甲苯所萃取出的沥青中的砂砾含量则在红外检出限以下。丙酮/正庚烷复合溶剂及在6种ILs辅助下萃出的沥青相中均未检测到细小砂砾物质。实验结果为如何筛选适当ILs应用于非常规石油分离提供了科学基础。     

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...     

咪唑类离子液体的制备与合成

离子液体作为一类新型绿色介质,近年来获得了突飞猛进的发展。本文简单介绍了离子液体的种类及性质,列举了常用的常规法、微波法、超声法和电化学法等辅助合成方法;重点介绍了目前主要的功能化和手性咪唑离子液体合成方法。     

Optimized ionic liquids for toluene absorption

Conductor‐like‐screening model for real solvents (COSMO‐RS) method was used to analyze the solute‐solvent interactions and to screen Henry's law constant of toluene over 272 ionic liquids (ILs), to select high‐capacity absorbents. Thermogravimetric experiments were carried out to evaluate the toluene absorption by selected ILs at different temperatures and atmospheric pressure. Experimental equilibrium data were found in good agreement with COSMO‐RS predictions. Complete desorption of toluene by N₂ stripping was achieved, indicating an easy regeneration. The kinetic curves were described by a phenomenological diffusion model, obtaining effective diffusivities in reasonable concordance with those calculated by Wilke–Chang correlation. The separation process with selected ILs was modeled by Aspen Plus and a comparison with organic absorbents was carried out. Equilibrium‐ and rate‐based simulations were used to analyze the importance of thermodynamics and kinetics in toluene absorption by ILs. Current computational‐experimental research allowed selecting a set of suitable ILs for toluene absorption. © 2012 American Institute of Chemical Engineers AIChE J, 59: 1648–1656, 2013     

Novel method for determination of gas solubilities in low vapor pressure liquids

A modified version of a standard device for measuring gas adsorption and desorption isotherms and surface area of adsorbents and catalysts (ASAP (Accelerated Surface Area and Porosimetry System) 2020, Micromeritics USA) is used for the first time to measure gas solubilities (i.e., CO₂) in low vapor pressure liquids (i.e., the IUPAC standard ionic liquid 1‐hexyl‐3‐methylimidazolium bis(trifluoromethylsulfonyl)imide ([C₆mim][Tf₂N])) in the Henry's law region. The solubility data are in very good agreement with the reported data in literature. Furthermore, the Henry's law constants are calculated from the solubility data and compared to the experimental data found in literature. The results from this study demonstrate that Micromeritics ASAP 2020 is a suitable apparatus for gas absorption by solvents with reduced vapor pressures. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2981–2986, 2017     

Ionic liquids for absorption and separation of gases: An extensive database and a systematic screening method

Ionic liquids (ILs) have attracted considerable attention in both the academic and industrial communities for absorbing and separating gases. However, a data‐rich and well‐structured systematic database has not yet been established, and screening for highly efficient ILs meeting various requirements remains a challenging task. In this study, an extensive database of estimated Henry's law constants of twelve gases in more than ten thousand ILs at 313.15 K is established using the COSMO‐RS method. Based on the database, a new systematic and efficient screening method for IL selection for the absorption and separation of gases subject to important target properties is proposed. Application of the database and the screening method is highlighted through case studies involving two important gases separation problems (CO₂ from CH₄ and C₂H₂ from C₂H₄). The results demonstrate the effectiveness of using the screening method together with the database to explore and screen novel ILs meeting specific requirements for the absorption and separation of gases. © 2017 American Institute of Chemical Engineers AIChE J, 63: 1353–1367, 2017     

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.     

离子液体气体干燥技术的研究进展

离子液体（ionic liquids, ILs）被视为化工中传统溶剂的优良替代物,使用它们作为溶剂吸收可凝性气体时,具有溶剂损失少、无腐蚀和稳定性强等优点。一些ILs具有很强的吸水性,所以在气体干燥领域ILs受到了广泛关注。本文介绍了用于预测气体在ILs中溶解度的预测型分子热力学模型和气体在ILs中的实验测量方法,具体分析了ILs对CH₄、CO₂等气体的干燥机理和工艺,最后对ILs用于气体干燥的基础研究作出展望。     

功能型离子液体的合成表征及CO2吸收性能

合成了两种传统型离子液体［bmim］BF₄和［emim］BF₄及含有胺基和羟基的功能型离子液体［NH₂P-mim］Br、［NH₂-e-mim］BF₄、［OH-e-mim］Br,并对合成的离子液体进行IR和¹H NMR表征。常温常压条件下,对所合成的离子液体开展CO₂吸收性能实验,发现胺基改性离子液体［NH₂P-mim］Br、［NH₂-e-mim］BF₄和羟基改性离子液体［OH-e-mim］Br的CO₂饱和吸收量分别是常规离子液体的3～9倍和1～2倍,且含有乙基官能团的离子液体吸收平衡时间普遍较短。最终探讨了温度、CO₂分压等对功能型离子液体吸收CO₂过程的影响。     

Predictive molecular thermodynamic models for ionic liquids

Predictive molecular thermodynamic models can bridge the gap between the microscopic molecular level and macroscopic system scale. Over the past few decades, ionic liquids (ILs), as a class of green solvents and functional materials, have received widespread research interest in the field of chemical processing owing to their unique physicochemical merits. This review aims to provide an easy-to-read and exhaustive reference regarding state-of-the-art predictive thermodynamic models for ILs, with more focuses on UNIFAC- and COSMO-based models and various applications involving phase equilibrium prediction, guidance for IL screening and design, and building equilibrium stage models for separation processes. This review provides a theoretical perspective on the structure–property relationships between molecular structures and phase behaviors for the systems and the constituted components covering a multi-scale viewpoint from molecular level to industrial scale. Moreover, the predictive capacities of different thermodynamic models are comprehensively compared.     

Cuprous-based composite ionic liquids for the selective absorption of CO: Experimental study and thermodynamic analysis

Three cuprous-based composite ionic liquids (ILs) [EimH][OAc]–xCuOAc (x = 0.5, 0.6, 0.7) were prepared and employed for efficient absorption of CO. It is shown that the cuprous composite IL [EimH][OAc]–0.6CuOAc exhibited the largest absorption capacity for CO (0.031 g/g at 293.15 K and 1 bar) and had a record CO/N₂ selectivity of 967, which is better than most of common ILs and solvents reported in the literature. The results of Fourier transform infrared (FTIR) spectra, electrospray ionization mass spectrometry (ESI-MS) analysis, and theoretical calculations reveal that such superior CO capacity mainly resulted from two kinds of chemical interaction between CO and the active anionic species [Cu(OAc)₂]⁻ in [EimH][OAc]–0.6CuOAc. Furthermore, a “deactivated IL model” was further proposed to accurately describe the absorption behavior of CO in [EimH][OAc]–0.6CuOAc, in which the thermodynamic parameters including Henry's law constants, reaction equilibrium constants, and absorption enthalpies were estimated by the correlation of the experimental solubilities of CO.