CFC混合替代物的汽液平衡研究

自行安装并调试了一套用汽液双循环法测定加压下的汽液平衡数据的实验装置。通过对设备的测温、测压及相平衡测定系统进行调试、校核,表明该装置测定的汽液平衡数据是可靠的。用本实验装置分别测定了HCFC22+HCFC142b二元体系在313.15K、322.80K和328.15K三个温度下的汽液平衡实验数据;HCFC22+HFC152a二元体系在313.15K和328.15K两个温度下的汽液平衡实验数据;HCFC22+HFC152a+HCFC142b三元体系在313.15K、323.15K、328.15K和338.15K四个温度下的汽液平衡实验数据。最后,用Peng-Robinson状态方程对实验数据进行了成功的关联。     

异丙醇-水-含盐复合溶剂体系汽液平衡

用改进的Othmer汽液平衡釜测定了101．3kPa下异丙醇-水-含盐复合溶剂体系在三个不同溶剂比(1：1,0．5：1,2：1)下的汽液平衡数据,选定的6种复合溶剂是乙二醇 氯化锂,乙二醇 氯化钙,乙二醇 醋酸钾,乙二醇 氯化锂 氢氧化钾,乙二醇 氯化钙 氢氧化钾和乙二醇 醋酸钾 氢氧化钾。汽液平衡实验结果表明,所选的6种含盐复合溶剂均能显著提高异丙醇-水的相对挥发度,其中含氯化锂复合溶剂效果明显优于其他溶剂。用Wilson模型和NRTL模型对实验数据进行了关联,汽相组成平均偏差(△ym）小于022,温度平均偏差(△Tm)小于0．65K。     

沸点分析法在二元和三元体系汽液平衡测定中的应用

本文用沸点分析法测定了101.325kPa压力下,苯-甲苯二元体系和苯-甲苯-四氯化碳三元体系的汽液平衡数据。为了获得该三元体系的推算结果,同时又测定了苯-四氯化碳和甲苯-四氯化碳两组二元体系的汽液平衡数据,所有二元体系的汽液平衡数据用NRTL方程进行了热力学关联,并用获得的二元参数对三元体系的汽液平衡进行了预测,预测结果和实验结果符合良好。     

氟里昂—22—乙醇,氟里昂—22—异丙醇体系高压汽液平衡研究

用静态法装置测定了氟里昂-22-乙醇体系在343.25,361.70,382.65K和氟里昂-22-异丙醇体系在363.71,382.75K下的高压汽液平衡数据,并用PengRobinson状态方程对实验数据进行了成功的关联计算。     

乙醇-水-复合溶剂体系汽液平衡

用改进的Othmer汽液平衡釜测定了101 3kPa下乙醇-水-复合溶剂6个体系在不同溶剂比下的汽液平衡数据,6种复合溶剂为:乙二醇+氯化锂,乙二醇+氯化钙,乙二醇+醋酸钾,乙二醇+氯化锂+氢氧化钾,乙二醇+氯化钙+氢氧化钾,乙二醇+醋酸钾+氢氧化钾。并用Wilson模型和NRTL模型对实验数据进行了关联,结果良好,大部分体系汽相组成平均偏差小于0 02,泡点温度平均偏差小于1K。     

乙醇/丙醇-水-复合溶剂体系汽液平衡研究

为研究复合萃取溶剂体系下醇-水的汽液平衡,分别选用盐质量浓度为0.2 g/mL的乙二醇+氯化锂、乙二醇+醋酸钾2种复合萃取溶剂,测定了101.3 kPa下不同溶剂体积比(0.5∶1,1∶1,2∶1)时乙醇-水和丙醇-水的汽液平衡数据。分别用W ilson和NRTL热力学模型对所测汽液平衡数据按拟三元体系进行了关联。利用工业规模的实验装置,对测定结果进行了验证。结果表明,复合萃取溶剂能使乙醇-水和丙醇-水体系的共沸点消失,大大改变了体系中醇与水的相对挥发度。关联结果表明,W ilson热力学模型较NRTL热力学模型更适于乙醇/丙醇-水复合萃取溶剂体系。工业规模生产数据验证了所测定数据的可靠性,乙醇产品纯度可达到99.85%。     

用鼓泡平衡釜测定高温汽液平衡数据及对总压测定的探讨

本文用改进了的鼓泡平衡釜测定了均三甲苯-偏三甲苯体系在411.4K、424.2K、437.0K三个温度下,以及甲苯-正丁醇体系在353.5K及373.2K二个温度下的汽液平衡数据,所得数据均通过热力学一致性检验,实验数据用Wilson方程进行了关联,两个二元体系的计算值与实验值的偏差|△Y|<0.005,△Ymax<0.01。文中还就鼓泡平衡釜总压确定问题进行了探讨。     

常压下叔丁醇-水-乙二醇体系汽液平衡测定与关联

在常压(101.3 kPa)下,采用改进的Othmer汽液平衡釜测定了叔丁醇-乙二醇体系的汽液平衡数据,对所测得的数据进行热力学一致性检验,结果表明实验数据符合热力学一致性。用NRTL模型对叔丁醇-乙二醇体系的汽液平衡数据进行关联,得到二元交互作用参数,并用这些参数计算汽相组成及平衡温度,计算结果与实验数据吻合。测定了叔丁醇-水-乙二醇三元体系的汽液平衡数据,乙二醇存在下,叔丁醇-水体系的相对挥发度大幅提高,证明乙二醇是萃取精馏分离叔丁醇-水体系的优良溶剂。     

苯乙烯—丁二烯共聚物的表征：稀溶液性质的研究

用紫外／示差双检测器ＧＰＣ仪，小角激光光散射仪及红外光谱仪测定了苯乙烯（Ｓｔ）－丁烯共聚物的微观结构，分子量及其分布、组成分布及稀溶液特性。实验表明，Ｋ树脂是ＳＢＳ，ＳＢ和ＰＳ三段聚合物的混合物；在四氢呋喃，甲苯，氯仿和环已烷４种溶剂中，Ｋ树脂Ｍ基本一致，但其特性粘数与溶剂有关，其大小按溶剂四氢呋喃、甲苯、氯仿、环已烷顺序递减。因产Ｋ树脂稀溶液的性质与国外试样基本相似。     

用拟二元方法研究iPP-DBP-DOP三元体系的热致相分离热力学

采用拟二元方法研究等规聚丙烯（iPP）‐邻苯二甲酸二丁酯（DBP）‐邻苯二甲酸二辛酯（DOP）三元聚合物溶液的热致相分离热力学,得出了拟二元相图的数学关联方法.采用光学显微镜法测定浊点温度, 采用差式扫描量热法（DSC）测定熔点、动态结晶温度.利用浊点测定数据回归聚合物-共溶剂的交互作用参数 χ的表达式,χ是共溶剂配比和温度的函数,以此为基础计算的拟二元相图与实验数据吻合较好.发现共溶剂中DBP份数增加,相分离类型由单纯固液分相形式转变为液液分相、固液分相依次发生形式,共溶剂配比能调控拟二元相图结构.研究表明,只需测定一个较低冷却速率下几种共溶剂配比的拟二元溶液的浊点温度、分别测定几个冷却速率下iPP–DOP二元溶液的动态结晶温度即可掌握该三元溶液热致相分离热力学的全部信息.其可用来指导制膜过程,并能准确预测形成的膜结构形貌.     

Influence of molecular weight of poly (methyl methacrylate) on its miscibility with poly (vinyl chloride) in the solution

In this work, the molecular weight effect on miscibility between poly(vinyl chloride) (PVC) and poly(methyl methacrylate) (PMMA) in cyclohexanone(CH) solutions at 30 °C was examined by the viscometric method. Three samples of PMMA were prepared by emulsion polymerization, which molecular weights were changed by tert-dodecyl-mercaptan (TDDM) content. The parameter Δb is used to predict polymer-polymer miscibility of PVC/PMMA/cyclohexanone blend. Δb values indicated that the highest molecular weight of PMMA is immiscible with PVC resin. The molecular weight of PMMA decrease with the increase of the contention of TDDM, and the contribution of miscibility PVC/PMMA blend in CH is better.     

碳酸二甲酯-苯甲醇体系汽液平衡的研究

试验测定了碳酸二甲酯-苯甲醇体系在常压下的汽液平衡数据,采用Herrington法对数据进行了热力学一致性检验,结果表明所测数据符合热力学一致性。同时依据测定的汽液平衡数据计算出碳酸二甲酯及苯甲醇的无限稀释活度系数,求出Wilson活度系数模型参数,并计算了该体系于413.15 K的汽液平衡数据。     

Vapor-Liquid Equilibrium of Copolymer＋ Solvent Systems： Experimental Data and Thermodynamic Modeling with New UNIFAC Groups

Vapor-liquid equilibrium （VLE） data for copolymer solutions are necessary for several chemical processes. However, VLE data for copolymer solutions in the published report are rare. In this study, experimental VLE data for binary systems copolymer＋solvent were obtained using a gravimetric-sorption apparatus. The studied systems were hexane＋poly （21% acrylonitrile-co-butadiene）, hexane＋poly （33% acrylonitrile-co-butadiene）, hexane＋poly （51% acrylonitrile-co-butadiene）, hexane＋poly （23% styrene-co-butadiene）, hexane＋poly （45% styrene-co-butadiene）, and benzene＋poly （44% styrene-co-methyl methacrylate） in the range 50-70℃. The experimental data were correlated with the UNIFAC and Elbro-FV group contribution models for the activity coefficient. Two sets of functional groups had been used to represent the monomers in copolymers： literature groups and new proposed groups. The mean deviations between experimental and calculated mass fractions about 2.4% with Elbro- FV and 13.3% with Zhong were observed when the groups proposed in this study were used, and of 3.5% for E1- bro-FV and 13.2% for Zhong, when literature grouns were used.     

Representation of vapor–liquid and liquid–liquid equilibria for binary systems containing polymers: Applicability of an extended flory–huggins equation

For some binary systems, an extended Flory–Huggins equation is applicable to both vaporliquid equilibria (VLE) and liquid–liquid equilibria (LLE) using the same adjustable parameters. New LLE and VLE data are reported for polystyrene (PS) (MW = 100,000)/cyclohexane and for poly(ethylene glycol) (PEG) (MW = 8,000)/water. Experimental results for the PS/cyclohexane system agree well with the semiempirical model, whereas those for PEG/water do not, probably because, for PEG/water, the temperature range of the VLE data is about 55°C lower than that of the LLE data. Excellent fits were obtained for our previously published experimental results for PS/cyclohexane (upper critical solution temperature, UCST), PS/ethyl acetate (lower critical solution temperature, LCST), PS/tert-butyl acetate and PS/methyl acetate (both UCST and LCST), and PEG/water (closed-loop). The semiempirical model also fits well with new data obtained for the polymer blend PS/poly(vinyl methyl ether). © 1993 John Wiley & Sons, Inc.     

New method of determining miscibility in binary polymer blends through hydrodynamic interaction: The free volume approach

A new method has been developed to determine the probability of miscibility in binary polymer blends through hydrodynamic interaction. This is achieved by the measurement of the free volume content in blends of carefully selected systems—styrene acrylonitrile (SAN)/poly(methyl methacrylate) (PMMA), PMMA/poly(vinyl chloride) (PVC), and PVC/polystyrene (PS)—with positron annihilation lifetime spectroscopy. The free volume content can predict the miscible/immiscible nature of the blends but provides no information on the extent of miscibility for different compositions of the blends. We have generalized a model used to understand the viscometric behavior of polymer/solvent systems to polymer/polymer systems through the free volume approach. This model provides two important parameters: a geometric factor (γ) and a hydrodynamic interaction parameter (α). γ depends on the molecular architecture, whereas α accounts for the excess friction at the interface between the constituents of the blend, and we propose that α can serve as a precursor to miscibility in a system and indicate which composition produces a high probability of miscibility. The efficacy of this proposition has been checked with measured free volume data for the three blend systems. The SAN/PMMA system produces a maximum α value of ?209 at 20% PMMA; PVC/PMMA produces a maximum α value of ?57 at 10% PMMA. Interestingly, for the PS/PVC system, α is close to zero throughout the entire concentration range. Therefore, we infer that α is perhaps an appropriate parameter for determining the composition‐dependent probability of miscibility in binary blend systems. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

101.3 kPa 下环氧环己烷-环己酮气液平衡的测定及关联简

Many by-products are generated in the process of oxidizing cyclohexene to produce 1,2-epoxycyclohexane by hydrogen peroxide, including cyclohexanol, cyclohexanone, etc. To obtain high-purity 1,2-epoxycyclohexane, the by-products must be removed through rectification. Refining 1,2-epoxycyclohexane through rectification requires vapor-liquid equilibrium （VLE） data of the related system. Therefore, the VLE data of 1,2-epoxycyclohexane- cyclohexanone system were measured at 101.3 kPa using an improved EC-2 VLE still. The thermodynamic consistency of the data was then tested by Herington＇s method and the rigorous point-to-point method. The results obtained were exemplary. The VLE data were correlated by the Wilson and non-random two-liquid （NRTL） equations, using the error sum squares of the vapor composition as the objective function to obtain the model parameters. The difference between the calculated values and the experimental data is minor, indicating that the VLE data are suitable for engineering design.     

Vapor-liquid equilibria of water+monoethanolamine system

The accurate design of carbon dioxide separation processes by the absorption method requires knowledge of the vapor-liquid equilibrium of aqueous alkanolamine systems. MEA (monoethanolamine) is widely used for the separation of carbon dioxide by the chemical absorption process. The equilibrium apparatus was tested by comparing the measured VLE data for the methanol+ethanol system with the literature data. The isobaric vapor liquid equilibrium data were measured for the water+MEA binary system by using a modified Stage-Muller equilibrium still with circulation in both phases. The vapor liquid equilibrium data of water+MEA were measured in the pressure range from 50.0 to 70.0 kPa and temperature range from 355.2 to 430.3 K. The measured data were correlated with the UNIQUAC and NRTL activity coefficient models. This article is dedicated to Professor Chul Soo Lee in commemoration of his retirement from Department of Chemical and Biological Engineering of Korea University.     

Vapor-liquid equilibria for (methyl tertiary butyl ether+methanol+octane) and (methyl tertiary butyl ether+methanol+i-octane) systems at atmospheric pressure

Isobaric vapor-liquid equilibria (VLE) of two ternary systems (methyl tertiary butyl ether+methanol+ octane and methyl tertiary butyl ether+methanol+i-octane) were measured at atmospheric pressure by using a modified Othmer-type circulation apparatus. The VLE data of these ternary systems can be predicted by Wilson equation with the parameters determined by VLE data of constituent binary systems.     

气液平衡数据测定装置可靠性的检验

介绍了气液平衡数据测定装置可靠性的一种检验方法。以气相单循环气液平衡仪为实验装置,分别对乙醇-水体系及水-醋酸体系的常压气液平衡(VLE)数据进行了测定,用气相色谱仪分析气、液相组成并与文献值比较,同时用Herington面积法对所测VLE数据进行热力学一致性的检验,从而考察了本实验装置测定气液平衡数据的稳定性及可靠性。     

Measurement and correlation of vapor-liquid equilibria of the binary carbon dioxide-chloroform mixture system

Binary vapor liquid equilibrium data of the carbon dioxide+chloroform system were measured at five isotherms from 310.13 K to 333.32 K. A circulating type apparatus with on-line gas chromatography was used in this study. The experimental data were correlated by classical Peng-Robinson equation of state using van der Waals one fluid mixing rules and the multi-fluid nonrandom lattice fluid (MF-NLF) equation of state.