水-丁酸-壬醇三相系统的液液平衡

Liquid-liquid equilibrium (LLE) data for the water butyric acid nonanol system have been determined experimentally at the temperatures of 298.15 K, 308.15 K and 318.15 K. Tie-line compositions were correlated by Othmer-Tobias method. The universal quasichemical functional group activity coefficient (UNIFAC) and modified UNIFAC methods were used to predict the phase equilibrium in the system using the interaction parameters between CH3, CH2, COOH, OH and H2O functional groups. Distribution coefficients and separation factors were evaluated for the immiscibility region.     

Liquid-Liquid Equilibria of Water Butyric Acid Nonanol Ternary System

Liquid-liquid equilibrium (LLE) data for the water butyric acid nonanol system have been determined experimentally at the temperatures of 298.15 K, 308.15 K and 318.15 K. Tie-line compositions were correlated by Othmer-Tobias method. The universal quasichemical functional group activity coefficient (UNIFAC) and modified UNIFAC methods were used to predict the phase equilibrium in the system using the interaction parameters between CHs, CH2, COOH, OH and H2O functional groups. Distribution coefficients and separation factors were evaluated for the immiscibility region.     

水-醋酸-醋酸正丁酯三元体系液液平衡研究

文章用液液平衡装置在常压下,测定了水．醋酸-醋酸正丁酯三元体系40℃的液液相平衡数据。运用Othmer-Tobias方法对系线组成进行关联。由实验数据回归确定了NRTL、UNIQUAC以及修正的UNIFAC活度系数模型参数,并运用这些模型对体系相平衡进行了预测。将实验数据与关联结果比较,结果表明,三种方程均能较好地对溶液组成进行预测,其中UNIQUAC方程的拟合精度最好。     

Liquid-liquid equilibrium for the quaternary system of o-xylene(1)+water(2)+butyric acid(3)+ethyl acetate(4) at 25 °C and atmospheric pressure

The liquid-liquid equilibrium for the quaternary system of o-xylene(1)+water(2)+butyric acid(3)+ethyl acetate(4) was measured at 25 °C and atmospheric pressure. Binodal curves, tie-lines, distribution, and selectivity for the quaternary system have been determined in order to investigate the effect of binary solvents, o-xylene and ethyl acetate, on extracting butyric acid from aqueous solution. In addition, these experimental tie line data were also compared with the values predicted by the UNIFAC model. It is found that UNIFAC group interaction parameters used for LLE could not provide a good prediction.     

UNIFAC模型法计算含己内酰胺体系的相平衡(英文)

An extended liquid-liquid equilibrium (LLE) UNIFAC model is proposed to describe phase equilibria of mixtures containing caprolactam. In this model, caprolactam is introduced as a new group. New group interaction parameters are calibrated from 156 sets of liquid-liquid equilibrium data. The present model gives satisfactory correlation and prediction in liquid-liquid equilibrium, including quaternary systems containing the mixed solvent of an alcohol and an alkane. The model can be applied to predict caprolactam solubility in water and benzene accurately. Freezing point and vapor-liquid equilibrium of binary systems containing caprolactam are also predicted with the extended LLE UNIFAC model. Satisfactory prediction results are obtained.     

Solvent extraction of aromatics from middle distillates: Equilibria prediction method by group contribution

This work describes a method of calculating liquid-liquid aromatics extraction of a middle distillate. The group contribution models of the ASOG and UNIFAC type are investigated. Four vapour liquid equilibrium (VLE), two solid-liquid equilibrium (SLE), three binary and six ternary liquid-liquid equilibrium (LLE) have been measured. The parameters of the models are based mainly on the data of the systems having 10–20 carbon number. VLE, SLE, and infinite dilution activity coefficient data (17–245°C) have been used for calculating interaction parameters between hydrocarbon groups and LLE data (20–80°C) for interaction parameters of dimethylformamide-hydrocarbon groups. Middle distillate representation is based on mass spectrometric and gas chromatographic analysis and on limited data of middle distillate-DMF liquid-liquid equilibrium. It is shown that the performance of ASOG and UNIFAC models are sufficiently valid in representation of data base and in extraction calculations. Considering the predictive character and the rapidi of its application this method can be useful in the preliminary study of extraction processes.     

合成硝基麝香三元体系的固液平衡

通过试验测定了合成硝基麝香二元体系的固液平衡数据,回归并修正了UNIFAC模型的相互作用参数,使UNIFAC模型具有更高的预测功能;为了评价修正后的UNIFAC模型对合成硝基麝香三元体系的预测功能,利用试验测定的溶解度数据和修正后的UNIFAC模型计算值进行了比较,结果表明相互作用参数的修正是理想的.     

甲苯-正己烯-二甲基亚砜液-液平衡数据的测定与关联

裂解汽油是含有烯烃的重要芳烃资源,二甲基亚砜(DMSO)能够从高烯烃含量组分中选择性萃取芳烃,测定相应体系液-液平衡是裂解汽油中的芳烃萃取过程研究开发的理论基础。测定了常压下293.15、298.15、303.15 K时甲苯-正己烯-DMSO体系液-液平衡数据,获得了三元体系的相图和褶点,并采用Hand方程和NRTL方程进行关联。体系中甲苯对正己烯选择性系数为2～6,表明DMSO萃取分离甲苯和正己烯理论上可行。通过体系液-液平衡关联获得了NRTL方程模型参数,利用NRTL模型对该体系进行计算,计算值与实验值的平均偏差较小,说明NRTL模型适用于该体系的液-液平衡。     

间苯二酚溶剂萃取液液相平衡数据的关联

用NRTL模型对实验测定的24℃、101.33 kPa下醋酸正丁酯-间苯二酚-盐水及正丁醇-间苯二酚-盐水拟三元体系的液液相平衡数据进行了关联,分别得出了醋酸正丁酯-间苯二酚-盐水及正丁醇-间苯二酚-盐水拟三元体系的模型参数,并运用模型对体系相平衡进行了预测.将实验数据与关联结果比较,结果表明:NRTL模型能较好地对以...     

Application of UNIFAC models for prediction of vapor-liquid and liquid-liquid equilibria relevant to separation and purification processes of crude biodiesel fuel

Vapor-liquid equilibrium (VLE) of the methanol-biodiesel (BDF)/glycerin binary system and liquid-liquid equilibrium (LLE) of the water-BDF binary system and the methanol-BDF-glycerin and methanol-water-BDF ternary systems were predicted using several UNIFAC models: the latest original UNIFAC model, Kikic’s model, Fornari’s model, Dortmund-UNIFAC model, and LLE-UNIFAC model. The former VLE and latter LLE are used to design methanol recovery processes and separation and purification processes of crude BDF, respectively. Unfortunately, LLE data on the water-BDF binary system was not available. Instead, solubility of water in fatty acid methyl ester (one of the BDF constituents) was measured. By examining the deviation between predicted and experimental results, we determined which of the UNIFAC models was more useful for the design of those processes as follows: either the original UNIFAC model or Dortmund-UNIFAC model should be used for the methanol recovery process. The LLE-UNIFAC model and Dortmund-UNIFAC model were more useful for the recovery and water-washing processes of crude BDF and purification process of water-washed BDF, respectively.     

水-异丙醚-苯酚和水-异丁醇-苯酚体系的液液平衡研究

水-异丙醚-苯酚体系的研究在工业上和环境保护上具有重要意义,但至今未见到液液平衡(LLE)数据的报导今报导了这一系统在两个工作温度的LLE数据.为了寻找萃取剂异丙醚的替代物,我们同时进行了水-异丁醇-苯酚体系的液液平衡研究. 在常压下使用GC-14B气相色谱仪,测定了319 K和329 K时水-异丙醚-苯酚体系的液液平衡(LLE)数据以及水-异丁醇-苯酚体系在319 K和333 K时的LLE数据.用内标法测定了这些体系中除水以外的各组分浓度.在水-异丙醚-苯酚体系中,异丙醚测量的根均方误差为1.4%;苯酚测量的根均方误差为4.6%.在水-异丁醇-苯酚体系中,异丁醇测量的根均方误差为3.1%:苯酚测量的根均方误差为4.6%. 文中给出了上述四个等温截面的LLE数据,同时也给出了相应示意图.2003年我们用工作曲线法(外标法)给出了水-异丙醚-苯酚在319K的等温截面图.两者比较,总体上是类似的,但内标法结果更可靠.这次的研究,还纠正了当时的一个错误估计.对于水-异丁醇-苯酚体系的液液平衡研究表明,异丁醇也是从废水中萃取苯酚的良好萃取剂.但是异丁醇的再生及其循环利用并不如异丙醚那样容易.     

UNIFAC模型在草酸二乙酯合成体系中的应用

利用原始ＵＮＩＦＡＣ模型对ＣＯ气相催化偶联合成草酸二乙酸产物中的各组分进行了基团划分,用实验测定的二元物系等温汽液平衡数据,关联了ＣＨ２Ｏ／ＨＣＯＯ基团相互作用参数,汽液平衡计算值性实验值比较偏差较大。为提高推算精度,对碳酸二忆是进行新的基团划分,提出了ＵＮＩＦＡＣ新基团ＯＣＯＯ,重新关联基团相互作用参数并进行了汽平稳推算,结果令人满意。     

探讨UNIFAC法推算正、异丁醇精制系统中若干体系的汽液平衡——增补a_(CCOH,CHO)和a_(CHO,CCOH)基团相互作用参数

本文通过异丁醇-异丁醛体系汽液平衡的文献数据,增补了用于UNIFAC法的一对a_（CCOH,CHO）和a_（CHO,CCOH）基团相互作用参数。用UNIFAC法推算有关正、异丁醇精制系统的各类相平衡数据,其计算精确度接近或达到NRTL等方程的关联结果。由于此法基于基团性质加和性的假定,因此在具体应用时必须慎重地选择参数值,并用实验数据进行检验。     

Phase equilibrium data for aqueous solutions of formic acid with 2-ethyl-1-hexanol at T=(298.2, 308.2, 318.2, and 328.2) K

Liquid-liquid equilibrium (LLE) data for the system of (water+formic acid+2-ethyl-1-hexanol) were experimentally determined at T=(298.2, 308.2, 318.2, and 328.2) K and atmospheric pressure. A type-2 LLE was obtained for this ternary system. The influence of temperature on the equilibrium characteristics was found to be smallat the temperatures studied. Distribution coefficients and separation factors were calculated over the immiscibility regions. The experimental tie-line data were correlated using the UNIQUAC model. The values of the interaction parameters between each pair of the components were obtained for this thermodynamic model. The root mean square deviation (RMSD) between the observed and calculated mass fractions was 0.61%.     

LIQUID-LIQUID EQUILIBRIA OF ORGANIC COMPOUNDS: MEASUREMENT,CORRELATION AND PREDICTION†

The knowledge of phase equilibria is an important step in the development of extraction processes. This knowledge is usually gained from experiments. However, this procedure is expensive when a suitable solvent has to be found for a specific separation. Therefore methods for predicting phase equilibria are needed. While formerly these methods were largely based on empirical assumptions, the use of the concept of local compositions by Wilson⁶ offers a semi-empirical approach.

There is one disadvantage of this approach: the parameters of models like UNIQUAC or NRTL have to be fitted to different types of data, to liquid-liquid equilibria (LLE) for the immiscible pairs of components and to vapour-liquid equilibria (VLE) or other data for the miscible pairs in a system with mutual solubility.

To demonstrate the problem we performed measurements in the binary systems: n-octane/aniline and methylcylohexane/aniline. of both liquid-liquid equilibrium and vapour-liquid equilibrium: for the second type of measurements ebulliomeiry was used. The prediction of LLE has been improved with two new concepts. One is based on the well-known UNIFAC method. The use of the Lyngby-Dorlmund data bank made it possible to determine a new parameter table merely based on LLE data.

The second method is based on common UNIQUAC parameters which have been determined with the data base.     

LIQUID-LIQUID EQUILIBRIA OF ORGANIC COMPOUNDS: MEASUREMENT, CORRELATION AND PREDICTION†

The knowledge of phase equilibria is an important step in the development of extraction processes. This knowledge is usually gained from experiments. However, this procedure is expensive when a suitable solvent has to be found for a specific separation. Therefore methods for predicting phase equilibria are needed. While formerly these methods were largely based on empirical assumptions, the use of the concept of local compositions by Wilson⁶ offers a semi-empirical approach.

There is one disadvantage of this approach: the parameters of models like UNIQUAC or NRTL have to be fitted to different types of data, to liquid-liquid equilibria (LLE) for the immiscible pairs of components and to vapour-liquid equilibria (VLE) or other data for the miscible pairs in a system with mutual solubility.

To demonstrate the problem we performed measurements in the binary systems: n-octane/aniline and methylcylohexane/aniline. of both liquid-liquid equilibrium and vapour-liquid equilibrium: for the second type of measurements ebulliomeiry was used. The prediction of LLE has been improved with two new concepts. One is based on the well-known UNIFAC method. The use of the Lyngby-Dorlmund data bank made it possible to determine a new parameter table merely based on LLE data.

The second method is based on common UNIQUAC parameters which have been determined with the data base.     

水-丙烯酸-醋酸-甲苯四元体系液液平衡数据的测定与关联

采用液液平衡釜,在常压下,测定了293.15,303.15,313.15 K时水-丙烯酸-醋酸-甲苯四元体系的液液平衡数据,为萃取-非均相共沸精馏法精制丙烯酸选择适宜的溶剂提供依据.使用Othmer-Tobias方程对实验数据进行线性拟合.分别采用非随机双液(NRTL)和通用似化学(UNlQUAC)活度系数模型对实验体...     

动态法辅助筛选萃取精馏分离环己烷-苯混合物的溶剂

采用基于UNIFAC模型(改进UNIFAC模型)的较严谨的"动态法"替代传统的"静态法",以FORTRAN语言开发了萃取精馏法分离沸点接近液体混合物(含共沸物)的萃取剂筛选和多元气液平衡预测程序. 经文献中的乙醇-水体系气液平衡实验数据验证,UNIFAC模型和改进UNIFAC模型的平衡气相组成预测结果平均相对误差分别为3.26%和1.74%,表明所开发的程序具有良好的可靠性和适用性. 采用基于改进UNIFAC模型的"动态法"对萃取精馏法分离环己烷-苯混合物的萃取剂进行了计算机高通量筛选,根据适宜萃取剂选取原则和计算结果,经综合考虑选出较好的萃取剂为二氯甲烷和1,2,3-三氯丙烷. 选取二氯甲烷做实验验证,测定了环己烷-苯-二氯甲烷分离体系的部分气液平衡实验数据,结果表明实验值与计算值吻合良好. 以二氯甲烷作为萃取剂具有能耗低、待分离体系热稳定性好和有效能损失小的优点.     

Synthesis of tertiary amyl methyl ether (TAME): Equilibrium of the multiple reactions

The octane enhancer tertiary amyl methyl ether (TAME) is produced by liquid phase synthesis from methanol and a mixture of isoamylenes, namely 2-methyl-1-butene and 2-methyl-2-butene, using a sulfonic acid ion exchange resin as catalyst. Three reactions take place simultaneously in TAME synthesis: etherification of the two methylbutenes and their isomerisation. In order to study the equilibrium of the multiple reactions in TAME synthesis, the thermodynamic properties of the compounds in the liquid phase and equilibrium constants were calculated using a modified UNIFAC method to describe the nonideality of the system. Four parameters influencing the equilibrium conversion were derived and discussed in detail. Supplemental experiments were performed at three temperatures in the range from 303 to 343 K and at different initial molar ratios of educts. Equilibrium conversions of methanol were determined from these experiments and compared with calculated values. At 298 K the predicted activity based equilibrium constant was 22.9 for TAME synthesis from 2-methyl-1-butene and 1.6 for TAME synthesis from 2-methyl-2-butene; for isomerisation of 2-methyl-1-butene to 2-methyl-2-butene a value of 14.3 was obtained.     

Measurement and correlation of phase equilibrium data of the mixtures consisting of water,resorcinol, mesityl oxide at different temperatures

Liquid-liquid equilibrium (LLE) data were measured for the ternary system of water+resorcinol+mesityl oxide under atmospheric pressure at temperatures of (298.2, 323.2, 333.2, 343.2 and 353.2) K. The reliability of the experimental data was verified by the Hand and Bachman equations. The distribution coefficient and selectivity were calculated from the experimental LLE data, which showed high efficiency of mesityl oxide extracting resorcinol from the aqueous solution. The NRTL and UNIQUAC models were employed to fit the measured experimental LLE data and yield corresponding binary interaction parameters.