水-乙醇-1-丁基-3-甲基咪唑乙酸盐三元体系汽液平衡测定及模型

Vapor-liquid equilibrium (VLE) data were measured for ternary system water + ethanol + 1-butyl-3- methylimidazolium acetate ([bmim][OAc]), in a relatively wide range of ionic liquid (IL) mass fractions up to 0.8. Six sets of complete T-x-y data were obtained, in which the mole fraction of ethanol on IL-free basis was fixed separately at 0.1, 0.2, 0.4, 0.6, 0.8, and approximate 0.98. The non-random-two-liquid (NRTL) and electrolyte non-random-two-liquid (eNRTL) equations were used for correlation, showing similar deviations. The ternary VLE was also modeled with the correlation from two data sets, with the mole fractions of ethanol on IL-free basis being 0.1 and approximate 0.98. The VLE data were also reproduced satisfactorily. With the eNRTL model, the root-mean-square deviation for temperature is 0.79 K and that for vapor-phase mole fraction is 0.0094. The calculations are in good agreement with experimental data. The effect of the IL on the VLE behavior of the volatile components is also illustrated.     

Measurement and modeling of vapor-liquid equilibrium for ternary system water + 2-propanol + 1-butyl-3-methylimidazoliumchloride简

Vapor-liquid equilibrium （VLE） data for water ＋ 2-propanol ＋ 1-butyl-3-methylimidazolium chloride （[bmim]Cl） were measured. Six sets of complete T, x, y data are reported, in which the 2-propanol mole fraction on IL-free basis is fixed separately at 0.1, 0.2, 0.4, 0.6, 0.8, and approximate 0.98, while the IL mass fraction is varied from 0.1 to 0.8, in an interval of 0.1. The non-random-two-liquid （NRTL） and electrolyte non-random-two-liquid （eNRTL） equations are used to correlate the experimental data with satisfactory results. The ternary VLE behavior is also modeled with the parameters obtained by correlating two data sets, in which the mole fraction of 2-propanol on IL-free basis is approximately 0.1 and 0.98. In this way, the six sets of data are reproduced satisfactorily. With the eNRTL model, the root-mean-square deviation for temperature is 0.82 K and that for vapor-phase mole fraction is 0.0078. The influences of IL on activity coefficients and relative volatility of the volatile components are also graphically illustrated.     

神经网络技术用于醇水盐体系汽液平衡关联和预测

运用神经网络 ,对 32个醇水盐体系的汽液平衡数据进行了关联 ,计算值与实验值符合良好 ,泡点温度和汽相组成的平均偏差分别是 0 .93K和 0 .0 15。对未列入该模型的体系的汽液平衡进行了预测 ,也取得了较好的结果。     

Vapor Liquid Equilibria for Ionic Liquid/Ethanol/Water Systems and the Effect of Anion Hydrolysis

The performance of two tetrafluoroborate-based ionic liquids (ILs) as entrainers in the dehydration of water/ethanol azeotropic mixtures was evaluated. Isobaric vapor-liquid equilibrium (VLE) data were measured for the systems ethanol/water/1-butyl-3-methyl imidazolium tetrafluoroborate and ethanol/water /n-butylpyridinium tetrafluoroborate including the azeotropic region. VLE data for the ethanol/water, ethanol/IL, and water/IL binary mixtures were obtained at 100 kPa. The hydrolysis of the tetrafluoroborate anion was studied for both types of ILs by ¹⁹F NMR analysis. The hydrolysis of the tetrafluoroborate anion does not have much effect on the ethanol/water VLE. The ¹⁹F NMR analysis indicated that hydrolysis occurred at high mole fractions of water.     

Effect of methylimidazolium-based ionic liquids on vapor–liquid equilibrium behavior of tert-butyl alcohol + water azeotropic mixture at 101.3 kPa

Three ionic liquids(ILs),1-ethyl-3-methylimidazolium bromine([EMIM]Br),1-butyl-3-methylimidazolium bromine([BMIM]Br),and 1-hexyl-3-methylimidazolium bromine([HMIM]Br),were used as the solvent for separation of {tert-butyl alcohol(TBA)+ water} azeotrope.Vapor–liquid equilibrium(VLE)data for {TBA + water + IL}ternary systems were measured at 101.3 k Pa.The results indicate that all the three ILs produce an obvious effect on the VLE behavior of {TBA + water} system and eliminate the azeotropy in the whole concentration range.[EMIM]Br is the best solvent for the separation of {TBA + water} system by extractive distillation among the three ILs.The experimental VLE data for the ternary systems are correlated with the NRTL model equation with good correlations.Explanations are given with activity coefficients of water and TBA,and the experimental VLE-temperature data for {TBA or water + IL} binary systems.     

含离子液体乙醇-水物系等压汽液平衡数据的测定

用Ellis双循环汽液平衡釜测定了101.32 kPa下乙醇 水 三乙基铵硫酸氢盐(N-2,2,2,H］HSO4)的等压汽液平衡数据。实验结果表明,当［N-2,2,2,H］HSO4的摩尔分数为5%时乙醇 水二组分物系的汽液平衡线就开始偏离,［N-2,2,2,H］HSO4摩尔分数为10%、20%时,偏离程度增大;［N-2,2,2,H］HSO4表现出盐效应,使乙醇对水的相对挥发度发生改变,消除了乙醇 水物系的共沸点;含量越大,盐效应越明显。随着［N-2,2,2,H］HSO4含量的增加,乙醇对水的相对挥发度也随着增加;与其他离子液体相比较,［N-2,2,2,H］HSO4具有低成本、高效率的优点,可以作为乙醇-水物系萃取精馏分离的有机盐。用NRTL模型对数据进行了关联,关联的结果和实验计算值相当,符合实验趋势。     

Salting-out effect of ionic liquids on isobaric vapor-liquid equilibrium of acetonitrile-water system☆

This paper presents the vapor–liquid equilibrium (VLE) data of acetonitrile–water system containing ionic liquids (ILs) at atmospheric pressure (101.3 kPa). Since ionic liquids dissociate into anions and cations, the VLE data for the acetonitrile+water+ILs systems are correlated by salt effect models, Furter model and improved Furter model. The overall average relative deviation of Furter model and improved Furter model is 5.43%and 4.68%, respectively. Thus the salt effect models are applicable for the correlation of IL containing systems. The salting-out effect theory can be used to explain the change of relative volatility of acetonitrile–water system.     

Effects of imidazolium-based ionic liquids on the isobaric vapor–liquid equilibria of methanol + dimethyl carbonate azeotropic systems

The separation of methanol(MeOH) and dimethyl carbonate(DMC) is important but difficult due to the formation of an azeotropic mixture. In this work, isobaric vapor–liquid equilibrium(VLE) data for the ternary systems containing different imidazolium–based ionic liquids(ILs), i.e. MeOH + DMC + 1-butyl-3-methy-limidazolium bis[(trifluoromethyl)sulfonyl]imide([Bmim][Tf_2N]), MeOH + DMC + 1-ethyl-3-methyl-imidazolium bis[(trifluoromethyl)sulfonyl]imide([Emim][Tf_2N]), and MeOH + DMC + 1-ethyl-3-methylimidazolium hexafluorophosphate([Emim][PF6])) were measured at 101.3 kPa. The mole fraction of IL was varied from0.05 to 0.20. The experimental data were correlated with the NRTL and Wilson equations, respectively. The results show that imidazolium-based ILs were beneficial to improve the relative volatility of MeOH to DMC,and [Bmim][Tf_2 N] showed a much more excellent performance on the activity coefficient of MeOH. The interaction energies of system components were calculated using Gaussian program, and the effects of cation and anion on the separation coefficient of the azeotropic system were discussed.     

含离子液体乙腈-正丙醇体系的等压汽液平衡

常压(101.3 kPa)下, 测定了如下体系的汽液平衡数据:乙腈-正丙醇-氯化1-苄基-3-甲基咪唑([BzMIM][Cl])、乙腈-正丙醇-溴化1-苄基-3-甲基咪唑([BzMIM][Br])、乙腈-正丙醇-溴化1-己基-3-甲基咪唑([HMIM][Br]), 考察了3种离子液体对乙腈-正丙醇体系相平衡行为的影响。实验结果表明, 3种离子液体都能够提高乙腈对正丙醇的相对挥发度, 3种离子液体提高相对挥发度的顺序为 [BzMIM][Cl] > [BzMIM][Br] > [HMIM][Br]。用NRTL模型对测得的汽液平衡数据进行了关联, 关联结果与实验结果具有良好的一致性。     

含盐体系汽液平衡的热力学一致性检验

将拟二元方法与Barker法相结合可从三元含盐体系的P-T-x数据推算相应的平衡汽相组成,逐点比较其推算值与实测值,即可检验汽液平衡数据的热力学一致性.具体地对醇(乙醇、异丙醇)-水-盐(氯化钙、醋酸钾)体系的等压汽液平衡数据进行了热力学一致性检验,所得结果满意.含盐溶液P-T-x推算汽相组成的成功,为改进含盐溶液汽液平衡的测试手段创造了条件.     

运用EVLAC模型推算二元与多元体系的汽液平衡数据

运用EVLAC模型由二元恒温VE-x数据推算25个二元体系的76组恒温γ-x数据,γ的相对均方根偏差为0.27～3.7％;推算了其中六个二元体系的12组恒压汽液平衡数据,t的平均绝对偏差为0.1～0.5℃,y的平均绝对偏差为0.0022～0.0092摩尔分率;同时由二元数据推算了一个三元体系的四组恒温γ-x数据,γ的相对均方根偏差为1.7～2.1％。     

Isobaric vapor–liquid equilibrium for ternary system of ethanol,ethyl propionate and para-xylene at 101.3 kPa

Isobaric vapor–liquid equilibrium(VLE) data for the binary system ethyl propionate(2) + para-xylene(3) and ternary system ethanol(1) + ethyl propionate(2) + para-xylene(2) at atmospheric pressure(101.3 k Pa)were obtained by a VLE modified othmer still. All the experimental data passed a point to point consistency test of Van Ness method, which verified the data reliability. The Wilson and UNIQUAC activity coefficient models were employed to correlate the binary VLE data to obtain binary interaction parameters. Based on binary interaction parameters, ternary VLE data of ethanol(1) + ethyl propionate(2) + para-xylene(3) were predicted by Wilson and UNIQUAC models, which proved that predicted values are consistent with the experimental data.Furthermore, azeotropic phenomenon between ethanol and ethyl propionate disappears when the mole ratio of para-xylene and binary system of ethanol and ethyl propionate is 1:1. Therefore, this paper convinced that para-xylene is a proper extractive additive that could be used in extractive distillation to separate the binary azeotropic system of ethanol and ethyl propionate.     

甲酸-水-甲酸丁酯体系的等压汽液相平衡研究

用改进的Rose釜测定了101.33 kPa下甲酸-水、甲酸-甲酸丁酯、甲酸-水-甲酸丁酯(互溶区内)的等压汽液相平衡数据。考虑了甲酸在汽相中的缔合效应和非理想性,用Hayden-O’connell关联式修正了汽相的非理想性,用NRTL模型对甲酸-水和甲酸-甲酸丁酯体系的汽液平衡数据进行了关联,得到了相应的模型参数。利用得到的二元体系模型参数,结合部分三元体系汽液平衡数据,关联得到水-甲酸丁酯体系的模型参数。由关联得到的3对二元NRTL模型参数预测三元体系汽液平衡数据,温度平均偏差为1.20℃,甲酸的汽相平均偏差为0.0152,甲酸丁酯的汽相平均偏差为0.0184,实验值与预测值基本吻合。     

甲醇-乙酸-丙酸多元体系汽液平衡

用新型泵式沸点仪测定了在100kPa下甲醇-乙酸、甲醇-丙酸、乙酸-丙酸3个二元体系以及甲醇-乙酸-丙酸三元系在不同液相组成时的沸点,并用间接法T-p-x(温度、压力和液相摩尔分数)推算了3个二元体系的汽相平衡组成。3个二元体系活度系数分别用Wilson模型、NRTL模型、Margules模型和van Laar模型进行关联,用最小二乘法求出了它们的液相活度系数模型参数,同时,用这些模型参数来计算它们的汽相摩尔分数。所得的液相活度系数来计算3个二元体系的过量吉布斯自由能函数,且所研究的所有体系中各组分之间不存在共沸点。用3个二元体系Wilson模型参数对所测的三元体系数据进行关联,建立该系统汽液平衡的热力学模型并计算平衡时的汽相摩尔分数和泡点温度。由面积积分法检验这些模型参数计算的3个二元体系相平衡数据,得到很好的热力学一致性。     

Measurement and correlation of excess enthalpies for water+ethanol+1-buthyl 3-methylimidaozolium tetrafluoroborate system

It is difficult to find physical properties data for systems containing ionic liquids, excess molar enthalpies, binary interaction parameter, etc. In this study, the excess molar enthalpies were measured for water+ethanol+ionic liquid system using a isothermal microcalorimeter at 298.15 K. The ionic liquid used was 1-butyl 3-methyl imidazolium tetrafluoroborate, [BMIM] [BF₄]. The isothermal microcalorimeter (IMC) is a flow-type calorimeter that measures the heat of mixing directly, using specific mixing cell. By employing NRTL, electrolyte-NRTL and UNIQUAC models, binary interaction parameters were determined and investigated for the correlation with vapor liquid equilibrium (VLE). The e-NRTL model with the partial dissociation was employed to correlate the ionic liquid system. The binary data of VLE system were used from literatures. Specifically, UNIQUAC volume and surface area parameters were determined using Bondi radius.     

Statistical mechanics and artificial intelligence to model the thermodynamic properties of pure and mixture of ionic liquids

In this paper, the volumetric properties of pure and mixture of ionic liquids are predicted using the developed statistical mechanical equation of state in different temperatures, pressures and mole fractions. The temperature dependent parameters of the equation of state have been calculated using corresponding state correlation based on only the density at 298.15 K as scaling constants. The obtained mean of deviations of modified equation of state for density of al pure ionic liquids for 1662 data points was 0.25%. In addition, the performance of the arti-ficial neural network (ANN) with principle component analysis (PCA) based on back propagation training with 28 neurons in hidden layer for predicting of behavior of binary mixtures of ionic liquids was investigated. The AADs of a col ection of 568 data points for al binary systems using the EOS and the ANN at various temperatures and mole fractions are 1.03%and 0.68%, respectively. Moreover, the excess molar volume of all binary mixtures is predicted using obtained densities of EOS and ANN, and the results show that these properties have good agree-ment with literature.     

含盐溶液汽液平衡预测(Ⅰ)——Pitzer模型的扩展及其在多元体系中的应用

本文提出一种新的预测含盐溶液汽液平衡的方法.对Pitzer(1980)模型进行扩展后,将其简化成单参数形式,推广至多元电解质溶液;经过适当假定,得到计算含盐挥发性强电解质和水体系及含盐水醇体系的活度系数公式,这些公式仅含二元相互作用参数;由二元溶液的活度关联出该参数后,可用于含盐体系各种温度下汽液平衡的预测.关联了40个二元电解质水溶液及7个电解质甲醇溶液298.15K时的简化Pitzer方程的单参数;用以推算6个水盐体系和2个甲醇盐体系在320-403K的蒸汽压,得到满意的结果,182个数据点的平均偏差小于0.65kPa;用以预测5个不同类型的含盐三元体系的等温、等压汽液平衡,所得的平均偏差对于汽相组成、沸点、压力分别为0.015、1K和1.92kPa.     

α-蒎烯+β-蒎烯+对伞花烃的减压汽液平衡

用Dvorak-Boublik双循环汽液平衡釜测定了三元体系α-蒎烯（1）+β-蒎烯（2）+对伞花烃（3）在53.3和80.0 kPa下的汽液平衡数据,采用McDermott-Ellis对三元体系的实验数据进行热力学一致性检验,所有数据均通过一致性检验。采用相关二元体系的NRTL模型参数预测α-蒎烯+β-蒎烯+对伞花烃三元体系在53.3和80.0 kPa下的汽液平衡数据。结果表明：三元体系在两个压力下平衡温度的最大绝对偏差分别是0.80和0.86 K,平均绝对偏差分别为0.30和0.39 K。该体系在53.3 kPa下α-蒎烯和β-蒎烯在汽相中的最大绝对偏差分别为0.0096和0.0102,平均绝对偏差分别为0.0033和0.0028;在80.0 kPa下α-蒎烯和β-蒎烯在汽相中的最大绝对偏差分别为0.0083和0.0081,平均绝对偏差为0.0049和0.0025。实验结果为松节油体系主要成分的分离提纯提供了基础数据。     

Vapor–liquid equilibria of HFC-161 + HFC-32 + DMF ternary mixture for low-grade heat driven absorption refrigeration system

Ternary mixture of fluoroethane (HFC-161) + difluoromethane (HFC-32) + N,N-dimethylformamide (DMF) is a promising working fluid for absorption refrigeration system which is an important energy saving technology receiving more and more attention. Investigation on vapor–liquid equilibrium (VLE) is necessary for further study and the application in absorption system of the ternary mixture. Therefore, an experimental system with continuous vapor-phase circulation is set up, measuring VLE data within temperature range of 283.15 to 323.15 K. The experimental data is correlated with Wilson and NRTL models, and BP-ANN method, respectively. The calculating data of Wilson model has the largest relative deviation of 5.14% and average relative deviation of 2.65% for vapor pressure, being the best one. The deviation of molar fraction data obtained with BP-ANN model has the best average relative deviation 3.07%. However, NRTL model provides a smooth predicted surface. The correlated parameters of the three models are given.     

Experimental results for the vapor–liquid equilibria of (formaldehyde+1,3,5-trioxane+methanol+salt+water) systems and comparison with predictions

The salt effect on the vapor–liquid phase equilibrium (VLE) of solvent mixtures is of significant interest in the industrial production of 1,3,5-trioxane. Experimental data for the VLE of quinary systems (formaldehyde + 1,3,5-trioxane + methanol + salt + water) and their ternary subsystems (formaldehyde+salt+water), (1,3,5-trioxane+salt+water), and (methanol+salt+water) were system-atic measured under atmospheric pressure. The salts considered included KBr, NaNO3, and CaCl2. The extended UNIFAC model was used to describe the VLE of the salt-containing reactive mixtures. The model parameters were determined from the experimental VLE data of ternary systems or obtained from the literature, and then were used to predict the VLE of systems (1,3,5-trioxane + KBr + water), (methanol+KBr+water), (formaldehyde+KBr+water), and (formaldehyde+1,3,5-trioxane+methanol+salt+water) with salt=KBr, NaNO3, and CaCl2. The predicted results showed good agreements with the measured results. Furthermore, the model was used to uncover the salt effect on the VLE of these multi-solvent reactive systems.