有机物在离子液体中无限稀释活度因子及液液界面张力的定量机构-性质关系

用PM3半经验量子化学方法计算了烷烃、烯烃和芳烃等的疏水性参数lgP、偶极矩、前线分子轨道能隙和水合能等结构描述符,与实验测定的烃类在1-丁基-3-甲基咪唑六氟磷酸盐（［C₄MIM］［PF₆］）、1-烯丙基-3-甲基咪唑四氟硼酸盐（［AMIM］［BF₄］）、1-异丁烯基-3-甲基咪唑四氟硼酸盐（［MPMIM］［BF₄］）和［MPMIM］［BF₄］-AgBF₄ 4种离子液体中的无限稀释活度因子进行定量结构-性质关系（QSPR）研究,建立的QSPR模型具有良好的关联和预测能力.同时测定了烃类等溶质与离子液体［C₄MIM］［PF₆］的液液界面张力,发现其与无限稀释活度因子有相似的变化趋势,据此采用同样的结构描述符,建立了溶质与［C₄MIM］［PF₆］界面张力的QSPR模型,模型的关联能力良好.     

Modeling infinite dilution activity coefficients of organic-aqueous systems using a modified regular solution equation and cubic equations-of-state

Expressions derived from the regular solution equation and the generalized cubic equations-of-state (EOS) were employed to model the infinite dilute activity coefficient (γ^∞) of organic-aqueous systems. A database of 119 organic species in aqueous systems, divided into six classes, was gathered for models evaluations. The use of the molar density, the first order molecular connectivity, and the dipole moment appear to be adequate correlating variables for describing the structural dependence of the residual part in the modified regular solution equation (MRS). The Soave-Redlich-Kwong (SRK) and Peng-Robinson (PR) were specified and employed in the generalized cubic EOS form. The excess activity coefficient concept was used in the SRK and PR EOS models to account for the deficiency of EOS in dealing with highly non-ideal or polar systems. The abilities of two existing correlation models along with two modified versions of the UNIFAC model were also assessed. The proposed models provide creditable equations for correlating γ^∞ of organic-aqueous systems.     

Correlations for prediction of molecular diffusivities in liquids at infinite dilution

Diffusivities measured at 278.2 K to 323.2 K are reported for propene in acetic acid, acetone, n-butanol, chloroben-zene, N, N dimethyl formamide, ethyl acetate and n-octane. Measurements were made utilizing the steady-state capil-lary cell method. It was found that the diffusivities were reduced in the associating solvents when compared with those obtained in non-polar solvents at the same temperature. Three new empirical correlations have been developed for the prediction of diffusivities in liquids at infinite dilution and these are: for n-alkane solutions, for dissolved gases in organic solvents, and for dissolved gases in water.     

基于QSAR方法的离子液体毒性预测

离子液体因其极低的蒸气压、独特的溶解催化性能而备受关注,在许多领域展现出良好的应用潜力。但实现离子液体的工业化,离子液体的潜在毒性及环境影响也是重要的指标。针对离子液体的毒性性质,采用启发式算法筛选了5个影响离子液体毒性的关键参数,以离子液体对大肠杆菌（E. coil）毒性数据 MIC值作为研究对象,建立了40种咪唑类离子液体的定量结构-活性相关（QSAR）预测模型,使用外部测试集对模型进行了外部验证。结果表明,该模型具有良好的可靠性,可用于咪唑类离子液体的毒性预测。     

反相气相色谱法测定小分子溶剂在聚乙烯粒子中的无限稀释扩散系数

基于经典线性非平衡色谱过程的矩分析理论,用反相气相色谱法测定了323.15～358.15 K温度范围内二氯甲烷、三氯甲烷、四氯甲烷3种不同相对分子量的同系物小分子及正己烷在聚乙烯粒子中的无限稀释扩散系数。采用聚合物粒子直接填充的色谱柱,考察了温度、同系物小分子分子量及聚乙烯结晶度对扩散系数的影响。实验结果表明,对同一种小分子溶剂/聚乙烯体系,扩散系数均随温度升高而增大。不同相对分子量的同系物小分子在同一种聚乙烯中扩散系数随分子量增加而减小,聚乙烯结晶度增加也会导致扩散系数减小。采用文献中所报道的Krevelen扩散系数预测模型的计算值与实验测量值较为吻合,表明本文所采用的以聚合物粒子直接填充色谱柱的反相气相色谱扩散分析具有一定的可靠性。     

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。     

Viscosity of ionic liquids: Database,observation, and quantitative structure‐property relationship analysis

Viscosity data for ionic liquids (ILs) are needed for the theoretical study on viscosity or for the design/development of industrial process that involves ILs; understanding the relationship between ionic structure and viscosity is also desired to more rationally design and synthesize ILs with ideal viscosity. A database for the viscosity of pure ILs and their binary/ternary mixtures with molecular compounds is created by performing a comprehensive collection from published scientific literature sources worldwide covering the period from 1970 to 2009. In this database, there are 5046 data entries, 696 ILs, 306 cations, and 138 anions. Following the database, a direct observation of the effects of ionic structure along with temperature, pressure, and impurity on the viscosity is summarized, and a quantitative structure‐property relationship (QSPR) correlation is performed to understand the viscosity at a micro‐electronic or molecular level. Through direct observation and QSPR, the relationship between ILs structure and viscosity is addressed. © 2011 American Institute of Chemical Engineers AIChE J, 2012     

萃取精馏中离子液体萃取剂的研究进展

离子液体的低熔点和不挥发等特点使其较传统的萃取精馏萃取剂具有先天的优势,具有广泛的应用前景。本文介绍了离子液体作为萃取精馏萃取剂的研究进展,综述了汽液平衡法、无限稀释活度系数法等筛选离子液体萃取剂方法的研究成果以及目前用于计算含离子液体体系的相平衡模型研究进展,分析了离子液体萃取剂用于实用仍存在的问题,并展望了今后的研究方向。     

Effect of Ionic Liquids on Organic Reactions Based on Activity Coefficients at Infinite Dilution

It is important to know how ILs（ionic liquids） influence organic reaction. In this paper, activity coefficients at infinite dilution of more than 80 organic compounds in ILs are collected and analyzed systematically. Through the study on typical organic reactions happened in ILs, such as Diels-Alder, esterification and Friedel-Crafts reaction, the ratio of activity coefficients at infinite dilution of products and reactants is employed to estimate different effects of different structural ILs on the rate and selectivity of reactions.     

咪唑类离子液体的合成与表征

采用溴丁烷与N-甲基咪唑为原料合成了中间体溴化1-丁基-3-甲基咪唑，并通过离子交换反应制备离子液体1-丁基-3-甲基咪唑六氟磷酸盐以及1-丁基-3-甲基咪唑四氟鹏酸盐。产物结构经FT-IR和1^HNMR确认，其纯度通过HPLC分析均达到99．0％以上。     

Calculation of infinite dilution activity coefficients by the NRTL and UNIQUAC models

Infinite dilution activity coefficients have been calculated for 42 binary systems using the NRTL and UNIQUAC models. Temperature dependent parameters of the models are used in the calculations. These parameters have been estimated by using excess Gibbs free energy and enthalpy of mixing data simultaneously. The calculated values are compared with experimental infinite dilution activity coefficients obtained by extrapolation of vapor-liquid equilibrium (VLE) data published in the literature. The agreement between the calculated and experimental values is poor for highly nonideal system. The selection of the best model is difficult and may be system dependent.     

苯并噻唑类离子液体在乳酸酯中的溶解度测定

为促进离子液体的应用,在常压下由平衡法测定了3种新型苯并噻唑类离子液体在乳酸甲酯、乳酸乙酯中的溶解度,温度范围为253.15～333.15 K,用λh方程对溶解度数据进行了关联,关联效果理想。该类离子液体表现出的"温敏性"对其在反应结束后的回收及循环使用具有重要意义。     

Extending the UNIFAC model for ionic liquid–solute systems by combining experimental and computational databases

Considering that the predictive UNIFAC model is highly valuable for the solvent selection, process design and optimization of separation tasks, a large extension of this model to ionic liquid (IL)–solute systems is presented by combining experimental and COSMO-RS derived databases. The experimental infinite dilution activity coefficient (γ^∞) data of different solutes in ILs are first collected exhaustively to extend UNIFAC-IL to cover all involved IL and conventional functional groups. Afterwards, the experimental and COSMO-RS calculated γ^∞ are compared for different types of solutes to evaluate the potential of using COSMO-RS predictions as quasi-experimental data for further UNIFAC-IL extension. In the cases where COSMO-RS can provide quantitatively accurate predictions after calibration, additional γ^∞ database is specifically generated to regress more group interaction parameters in the UNIFAC-IL model. Finally, a large experimental liquid–liquid and vapor–liquid equilibria database is collected and employed to evaluate the predictive performance of the obtained γ^∞-based UNIFAC-IL model.     

离子液体萃取分离烃类化合物的研究进展

溶剂萃取分离技术广泛应用于石油化工领域,为石油石化产品的分离和提纯生产提供了有力的技术支撑。离子液体的结构可设计性、化学稳定性和热稳定性、极低的蒸气压等优点,使其在烃类化合物分离领域受到了研究者广泛关注。本文首先介绍了离子液体的性质及分类,根据分离目标不同,归纳了离子液体在芳烃-饱和烃分离、脱硫脱氮、烯烃-烷烃分离领域取得的最新进展,探讨了离子液体在油品分离领域研究中存在的问题和未来发展方向。文中指出：阳离子烷基侧链和极性是影响其对芳烃萃取效果的关键因素,然而对实际体系芳烃-饱和烃分离还有待进一步研究;离子液体对杂原子含硫含氮化合物均表现出较强的分离能力,但是碱性氮化物和非碱性氮化物不易通过一种离子液体同时脱除;氢键碱性是影响离子液体分离烯烃的关键因素,然而大部分离子液体对烯烃选择性仍然不高。根据不同的分离任务,从分子水平上认识离子液体结构与分离效果的关系,进而设计出兼具高效分离能力和低环境影响的新型离子液体,对提升油品中关键组分的高附加值转化利用具有重要意义。     

Framework for correlating the effect of temperature on nonelectrolyte and ionic liquid activity coefficients

A power‐law expression is proposed for correlating the temperature dependence of infinite‐dilution activity coefficients ( ) for nonelectrolyte solute–solvent binary pairs and for pairs including an ionic liquid: , where θ_ij = 0 for Lewis–Randall ideal solutions, θ_ij = 1 for classic enthalpy‐based Scatchard–Hildebrand regular solution and van Laar models, and ?5 < θ_ij < 5 for most real binaries. The exponent θ_ij is a function of partial molar excess enthalpy ( ) and entropy ( ) such that . Real binaries are classified into seven types corresponding to distinct domains of and θ_ij. The new method provides a framework for correlating phase‐equilibrium driven temperature effects for a wide variety of chemical and environmental applications. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3675–3690, 2014     

Synthesis and application of dicationic ionic liquids

Ionic liquids were synthesised that consisted of two methylimidazolium rings joined by a spacer 1–12 carbon atoms in length. The bis(triflic)imides with spacer ≤C₄ were solids; the others were liquid at room temperature. The polarity of the dication liquids and their performance in the extraction of phenol from water were compared with those of similar monocationic liquids. Copyright © 2005 Society of Chemical Industry     

Temperature dependence of kinetics and diffusion coefficients for ferrocene/ferricenium in ammonium-imide ionic liquids

The electrochemical behavior of ferrocene (Fc) and ferricenium (Fc⁺) was investigated by cyclic voltammetry with convolutional and semi-differential electroanalyses in the temperature range 298-373 K in the hydrophobic room temperature ionic liquid systems consisting of bis(trifluoromethanesulfone)imide anion with quaternary ammonium cation. The experimental results indicated that the redox reaction of Fc/Fc⁺ was reversible in this ionic liquid and the charge-transfer rate constant (k⁰) has been obtained. Mass transport towards the electrode is a simple diffusion process and the diffusion coefficient (D) for Fc/Fc⁺ has been also calculated. These results indicated that the k⁰ and D increased with increasing temperature in ionic liquids. The validity of the Arrhenius law was verified by investigating the temperature dependences of k⁰ and D.     

离子液体降解性的研究进展

离子液体作为绿色溶剂,在电化学、有机化学、生物化学等领域获得了广泛重视,但目前研究主要集中于离子液体的合成和应用,而与环保问题直接相关的降解性方面的研究不足,实现离子液体的降解是离子液体大规模使用之前必须要解决的问题。本文综述了离子液体的降解方法:化学降解法和生物降解法。化学降解法主要通过UV/H₂O₂体系、Fe(Ⅲ)/H₂O₂体系、电解体系实现对离子液体的降解;生物降解法则通过引入可以提供酶解位点的基团,或者单加氧酶将离子液体阳离子烷基侧链甲基末端氧化为羟基、醛基,形成羧基,再进行β-氧化过程。提出了针对化学降解法和生物降解法机理的不同,需要对离子液体的化学结构进行设计、适当控制烷基侧链的长度、引入易降解的功能基团等;同时筛选微生物,进而提高离子液体的降解效率。     

Prediction of infinite-dilution activity coefficients with neural collaborative filtering

Accurate prediction of infinite dilution activity coefficient (γ^∞) for phase equilibria and process design is crucial. In this work, an experimental γ^∞ dataset containing 295 solutes and 407 solvents (21,048 points) is obtained through data integrating, cleaning, and filtering. The dataset is arranged as a sparse matrix with solutes and solvents as columns and rows, respectively. Neural collaborative filtering (NCF), a modern matrix completion technique based on deep learning, is proposed to fully fill in the γ^∞ matrix. Ten-fold cross-validation is performed on the collected dataset to test the effectiveness of the proposed NCF, proving that NCF outperforms the state-of-the-art physical model and previous machine learning model. The completed γ^∞ matrix makes solvent screening and extension of UNIFAC parameters possible. Taking two typical hard-to-separate systems (benzene/cyclohexane and methyl cyclopentane/n-hexane mixtures) as examples, the NCF-developed database provides high-throughput screening for separation systems in terms of solvent selectivity and capacity.     

Ecotoxicological risk profile of ionic liquids: octanol‐water distribution coefficients and toxicological data

BACKGROUND: A knowledge of the toxicity of ionic liquids (ILs) and their influence on aquatic ecosystems must be assessed before an accurate judgment of their environmental benefits and prior to their industrial application. In the present work, the overall octanol‐water distribution coefficients (D_ow) of imidazolium‐based ILs were measured using the slow‐stirring method. Biological tests were performed to establish the toxicity of some of these imidazolium‐based ILs and to relate it with the D_ow. RESULTS: The D_ow values of the ILs investigated are low and concentration dependent, indicating that these ILs, at low concentrations, will not accumulate or bioconcentrate in the environment. Moreover, it is shown that the most hydrophobic anions present higher D_ow and higher toxicity, which means lower EC₅₀ values (the concentration of IL needed to decrease the luminescence of the marine bacteria Vibrio fischeri by 50% compared with the control organism luminescence). CONCLUSIONS: A new and more accurate interpretation of the partition of ionic liquids between water and 1‐octanol is presented. The work included measurement of new D_ow data and the study of their relation with water solubility and EC₅₀ values. Copyright © 2011 Society of Chemical Industry