含盐溶液汽液平衡预测

本文提出一种新的预测含盐溶液汽液平衡的方法。对Pitzer(1980年)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,这些公式仅含有二元相互作用参数;由二元溶液的活度关联出参数后,可用于含盐体系各温度下汽液平衡的预测。关联了四十个二元电解质水溶液及七个电解质甲醇溶液298.15K时的简化Pitzer方程的单参数;用以推算六个水盐体系和二个甲醇盐体系在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;用以预测五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、1.92kPa。     

CO2+共溶剂二元和三元体系的临界性质研究

The performance of supercritical fluid (SCF) as a solvent can be greatly affected by addition of an entrainer to the system.In this study,a constant volume visual method is used to measure the critical point of CO2 n-butyraldehyde,CO2 i-butyraldehyde and CO2 alcohol binary systems and CO2 entrainer trisodium salt of tri-(m-sulfonphenyl) phosphine(TPPTS) ternary systems,which provides us good theoretical basis for supercritical extraction and chemical reaction.The relationship between critical point and concentration of the entrainer are discussed.The phase behavior of binary system and that of ternary system are compared.The relationship between the concentration of TPPTS and critical point of binary systems are also discussed.     

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.     

Topology of Liquidus Phase Diagrams of Charge-Asymmetric Reciprocal Molten Salt Systems

An empirical extension of conformal ionic solution theory is presented which describes the solution behavior of a class of reciprocal molten salt systems, the A^+qA, B^+qB∥C^-qC, D^-qD charge-asymmetric systems. The thermodynamic properties of such ternary systems can be calculated from data on the standard free energy change for the metathetical reaction between the 4 pure constituents and solution data on the 4 binary subsystems. Calculated liquidus phase diagrams for the systems Na,Sr∥Cl,NO₃; Na,Ba∥Cl,NO₃; Li,K∥Cl,CrO₄; Li,K∥Br,CrO₄; and Na,Ca∥F,Cl agree well with measurements within experimental uncertainties. These systems are illustrative of a wide range of values of the thermodynamic quantities used in the calculations. The equations developed should prove useful as a test of the self-consistency of reported phase diagrams, as a means of calculating Liquidus temperatures in experimentally inaccessible regions, and as an aid in constructing phase diagrams from a minimum number of measurements.     

New Sorbents for Metal Salts based on Cation Exchange Extractants and Anion Exchange Resins: Their Preparation and Properties

Preparation and properties of binary sorbents containing a salt of cation exchange organic extractant in the matrix of a strongly basic anion exchanger were studied. Analysis of isotherms of exchange of chloride ions for dialkyldithiophosphate ions in the systems of various anion exchangers led to the conclusion that the stability of the binary sorbents depends on the amount of free water in the sorbent matrix. To improve the stability, it was proposed to use low cross-linked anion exchange resins or to use cation exchange extractants of moderate molecular volume. On the example of anion exchanger ММ-22x6.5 in the dibutyldithiophosphate form, it was shown that the binary sorbents efficiently recover chlorides of non-ferrous metals. The recovery increases in the series Ca²⁺<<Ni²⁺<Zn²⁺<<Cu²⁺. Because, in the systems studied, the anions are recovered together with cations, this leads to an increase in metal recovery in the presence of salting-out agents, and allows the desorbtion of the salts with water or with solutions of complexing agents. The binary sorbents offer good prospects for the recovery and separation of metal salts.     

制备方法对纳米熔盐储热性能及形成机理的影响

纳米材料能够改善高温熔盐的传热储热性能,提升大规模储热系统的储热和热交换效率,但目前仍未找到纳米熔盐的高效大规模制备方法。为优选纳米熔盐的高效大规模制备方法,以二元混合盐为基盐,采用高温熔融法和水溶液法分别制备纳米熔盐,用差示扫描量热法、热重分析法和微观形貌分析法,研究制备方法对纳米熔盐显热和储热性能提升、微观结构的影响,探索纳米熔盐形成机理。结果表明,两种制备方法均在搅拌90 min时制备的纳米熔盐性能达到最优,且高温熔融法制备纳米熔盐的熔化潜热和比热容分别比水溶液法高2.6%和28.18%;两种方法制备纳米熔盐的熔点较小,但对纳米熔盐的微观形貌存在明显影响,云核的形成与结构影响着纳米熔盐的储热性能。相比水溶液法,高温熔融法工艺简单,过程能耗低,纳米熔盐储热性能更好,适用于纳米熔盐的大规模生产和工程应用。     

Iodonium salt improves the dentin bonding performance in an experimental dental adhesive resin

The aim of this study was to evaluate the influence of an iodonium salt on the immediate and long-term microtensile bond strength to dentin of an experimental dental two-step, self-etching adhesive system. A model dental adhesive resin was formulated using bisphenol A glicidyl dimethacrylate (Bis-GMA), triethylene glicol dimethacrylate (TEGDMA), and hydroxyethyl methacrylate (HEMA), which was polymerized using four combinations of photo-initiators and coinitiators. A group using only camphorquinone (CQ), two binary systems (CQ and ethyl 4-dimethylamine benzoate (CQ+EDAB), CQ and diphenyliodonium hexafluorphosphate (CQ+DPIHFP)) and a ternary system (CQ+EDAB+DPIHFP) was investigated. Clearfil SE Bond (CSEB) was used as a commercial reference. Bond strength to bovine dentin was assessed through microtensile bond tests measured in MPa in a universal testing machine. The beam specimens were stored in distilled water at 37 °C for 24 h and 1 year. Two-way ANOVA and Student–Newman–Keuls' post-hoc tests were used to compare means of groups (α=5%) and failure modes classified under magnification. After 24 h, the ternary system showed a bond strength similar to that of the binary system CQ+EDAB and the commercial material. After 1 year of storage, the μTBS values of the group CQ+EDAB+DPIHFP showed a bond strength significantly higher (p<0.05) than those of the CQ, CQ+DPIHFP, and CQ+EDAB groups and no difference from that of the CSEB group. The ternary photo-initiator system with iodonium salt maintained increased bond strength to dentin of model self-etching adhesive systems after 1 year of aging.     

用拓扑法关联预测气液平衡的研究

用TTM法的十个模型关联了三个二元物系的VLE,并进行了模型选择,还关联了恒压、恒温二元系的VLE,又对用某温度下的参数预测相邻温度下的气液平衡以及由已知二元数据预测由组分同系物组成的其它二元系的气液平衡进行研究。结果表明,对所研究的含醇和丙酮物系,用TTM法关联的结果一般与用Margules方程相近,比用UNIQUAC,Wilson方程差,但用TTM法计算简单。用该法预测相邻温度下的VLE是可行的,而预测同系物组成的二元系尚需进一步研究。     

Mixtures of Organic and Inorganic Salts to Prevent Coal Freezing

Methods are proposed for the production of effective new reagents: binary salt systems that form low-temperature eutectics with water and readily melt ice, thereby preventing the freezing of coal in autumn and winter. Considerations of availability, cost, and physicochemical properties are of most importance in the selection of mixtures of organic and inorganic salts that are able to prevent the freezing of coal at temperatures down to–40°C. Research shows that the freezing point of solutions of organic-salt mixtures are lower than those of the individual mixture components. This may be explained by a synergetic effect. The consumption of the proposed salt mixtures for the prevention of coal freezing is considerably less than that of comparable systems containing only a single salt.     

无限稀活度系数的测定与应用

本工作改进了预饱和器结构,采用二级预饱和装置,用色谱测定了52组二元系在不同温度下88个无限稀活度系数,其中14个和文献报道的温度相近,数值与文献报道吻台.以乙苯为固定液的体系,其lnγ~∞与温度的倒数呈良好的线性关系,由此求出了相应的无限稀释溶解热.     

EQUILIBRIUM OF METALS WITH IMINODIACETIC RESIN IN BINARY AND TERNARY SYSTEMS

ABSTRACT

Experiments of binary and ternary ion exchange equilibrium of heavy metals and sodium were carried out in a complexing iminodiacetic resin Lewatit TP 207. First, binary equilibrium data were obtained at different temperatures and ionic strength and fixed to models considering two different ion exchange stoichiometrics. For ternary equilibrium data, two distinct simple models were applied. One to be applied to systems showing very different selectivity for the metals (for instance, Cu²⁺/Co²⁺/Na⁺) and the other for systems with similar selectivity for the metals (such as Zn²⁺/Co²⁺/Na⁺). The ternary equilibrium data obtained is presented in this work and fitted using the two above mentioned models. These models allow us to obtain the equilibrium parameters for binary and ternary system to be used in the design of equipment using this iminodiacetic resin.     

Measurement and correlation of the isobaric vapor-liquid equilibrium for mixtures of alcohol+ketone systems at atmospheric pressure

Vapor-liquid equilibrium (VLE) for binary mixtures composed of ethanol+methyl isobutyl ketone, 1-butanol+ methyl ethyl ketone, and 1-butanol+methyl propyl ketone systems was measured using a circulation type equilibrium apparatus at atmospheric pressure. The measured data and literature data for alcohol and ketone systems have been correlated by the UNIversal Quasi-Chemical (UNIQUAC) model with two binary interaction parameters and the non-random lattice fluid equation of state with hydrogen bonding equation of state (NLF-HB EoS) using a single binary interaction parameter. For the NLF-HB EoS calculations, the numbers of proton acceptor for ketones were adjusted between 0 and 1. The calculation results with the NLF-HB EoS are better than those with the UNIQUAC model.     

Poly(allyl glycidyl ether)‐block‐poly(ethylene oxide): A novel promising polymeric intermediate for the preparation of micellar drug delivery systems

Novel diblock copolymers designed for the preparation of micellar drug delivery systems, consisting of hydrophobic poly(allyl glycidyl ether) (PAGE) and hydrophilic poly(ethylene oxide) (PEO), were prepared, and their self‐assembly into micellar structures was studied. Copolymers differing in the length of the polymer blocks were purified and characterized. These amphiphilic copolymers with narrow molecular weight distributions were prepared through the anionic polymerization of allyl glycidyl ether with PEO monomethyl ether sodium salt as the macroinitiator. The PAGE–PEO copolymer readily formed small micelles with narrow size distributions via simple dissolution in water. The addition of pendant double bonds to the hydrophobic part of the chain was intended for further covalent modifications. Catalytic hydrogenation, the radical crosslinking of the micelle core, and the addition of thiol to double bonds of the copolymer were examples of such modifications that were proved to proceed with a quantitative yield for this copolymer. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 201–211, 2005     

醋酸脱水过程中对二甲苯+(醋酸,醋酸甲酯,醋酸正丙酯)和醋酸甲酯+醋酸正丙酯的二元汽液相平衡(英文)

The vapor-liquid equilibrium data of four binary systems (acetic acid +p-xylene, methyl acetate +n-propyl acetate, n-propyl acetate +p-xylene and methyl acetate +p-xylene) are measured at 101.33 kPa with Ellis equilibrium still, and then both the NRTL and UNIQUAC models are used in combination with the HOC model for correlating and estimating the vapor-liquid equilibrium of these four binary systems. The estimated binary VLE results using correlated parameters agree well with the measured data except the methyl acetate +p-xylene system which easily causes bumping and liquid rushing out of the sampling tap due to their dramatically different boiling points. The correlation results by NRTL and UNIQUAC models have little difference on the average absolute deviations of temperature and composition of vapor phase, and the results by NRTL model are slightly better than those by UNIQUAC model except for the methyl acetate +n-propyl acetate system, for which the latter gives more accurate correlations.     

Ion Rejection in Single and Binary Mixed Electrolyte Systems by Nanofiltration: Effect of Feed Concentration

Abstract

The objectives of this work were to investigate and compare the separation behavior of ions in single and binary mixed electrolyte systems by NF70, with emphasis on the effect of feed concentration. Experimental results showed that the anion rejection is lower in the binary mixed system compared to the single salt system. Anion rejection decreases with the enhancement of feed concentration of co‐existing electrolyte. As for cation rejection, Na⁺ rejection in the mixed electrolyte system is generally greater than that in the single NaCl system; whereas the separation performance of Ca²⁺ at high feed concentrations shows the opposite trend, and cannot be explained by the Donnan theory. Several possible mechanisms have been evaluated. Finally, the Spiegler‐Kedem equation was used and parameters were calculated.     

Prediction of vapor — liquid equilibria: Derivation of a new expression for vapor — liquid equilibrium correlations

To replace the interchange energy between two different types of molecules, two types of local energy parameters derived from Scott's two liquid concept are defined. When this definition is introduced into the quasichemical approximation, a new expression for correlating vapor-liquid equilibria in binary systems results. The new expression is semi-empirical in nature and for a binary system, it contains two adjustable parameters and a binary constant which are obtained from binary experimental data. It has been shown that the new expression can be used as a two-parameter equation. Its application was tested with thirty-four examples of highly non-ideal systems, including twenty-two systems at isobaric and twelve systems at isothermal conditions. Application to partially miscible systems is also examined. The results, correlated through the new expression, are compared with those obtained using the equations of Wilson and of Renon. The significance of the parameters of the new expression is discussed.     

Equation of state for the systems containing aqueous salt: Prediction of high pressure vapor-liquid equilibrium

An equation of state (EOS), which is based upon contributions to the Helmholtz energy, is presented for systems containing aqueous electrolyte solutions at high pressure. The Peng-Robinson equation of state is used to provide the Helmholtz energy of a reference system. The electrolyte terms consist three terms containing a modified Debye-Hückel term for long-range electrostatic interactions, the Born energy contribution for electrostatic works and a Margules term for short-range electrostatic interactions between ions and solvents. The binary and ternary interaction parameters of the equation of state are obtained by experimental osmotic coefficient data. Systems that were studied here are (water+ NaCl+SC-CO₂), (water+NH₄Cl+SC-CO₂), (water+Na₂SO₄+SC-CO₂) and (water+methanol+NaCl+SC-CO₂). It is found that the proposed equation of state is able to accurately represent the experimental data over a wide range of pressure, temperature and salt concentration.     

EXPERIMENTAL STUDIES OF NUCLEATION PHENOMENA WITHIN THERMAL BOUNDARY LAYERS—INFLUENCE ON CHEMICAL VAPOR DEPOSITION RATE PROCESSES

In carrying out partial vapor condensations using actively cooled surfaces it is known that 'mist' formation can occur within thermal boundary layers (Rosner and Epstein, 1968), dramatically modifying total deposition fluxes. Using a combination of flash-evaporation (Rosner and Liang, 1986) and laser probing techniques, we report new experimental results on binary alkali salt (K₂SO₄ + Na₂SO₄) deposition from combustion gases showing that the deposition rate of potassium sulfate first increases with the addition of sodium sulfate until the concentration of Na₂SO₄ reaches a (target surface temperature dependent) 'threshold' value. Further increases in the concentration of Na₂SO₄ dramatically decrease the total deposition rate of K₂SO₄, implying that potassium sulfate-containing microdroplets are formed within the thermal boundary layer, which, despite their thermophoretic drift toward the target, are not collected as effectively as the 'parent' K₂SO₄-vapor species. Laser light scattering measurements clearly reveal that suspended particles exist near the deposition surface under these conditions. Our experimental results on mass transfer rate and light scattering are consistent with those predicted using laminar boundary layer theory (Castillo and Rosner, 1989b) coupling both binary salt vapor deposition with particle vapor scavenging and deposition. Comparisons of our observed mist onset conditions (implying critical supersaturations near unity) with those expected using homogeneous nucleation theory suggest that the binary alkali sulfate mist nucleation mechanism is, instead, heterogeneous, even in our relatively 'clean' combustion products. Because of the; well-known vapor pressure reduction phenomenon associated here with the formation of non-ideal solutions, binary systems are shown to provide convenient 'vehicles' to investigate BL mist formation onset conditions and CVD-rate consequences without requiring the more extreme surface coolings characteristic of unary condensible vapor systems. An understanding of this dramatic phenomenon, obtained via such laboratory experiments and calculations, will allow its inclusion in future deposition rate calculations of engineering importance.     

Predicting NRTL binary interaction parameters from molecular simulations

A predictive approach for calculating the binary interaction parameters ( ) of the nonrandom two liquid (NRTL) local composition model is developed, combining molecular simulations with the two‐fluid theory. The binary interaction parameters are determined for the following three sets of model binary mixtures: water + methanol, methanol + methyl acrylate, and water + methyl acrylate. For each binary mixture, the interaction parameters are expressed in terms of molecular size and strength of interactions, which are in turn, calculated from molecular simulations. We show that the binary interaction parameters determined from simulations are in qualitative agreement with those estimated from regressing experimental data. The major factors that determine the binary interaction parameters are outlined based on simple thermodynamic arguments for each mixture. © 2018 American Institute of Chemical Engineers AIChE J, 64: 2758–2769, 2018     

含盐有机溶剂饱和蒸气压的测定和关联

采用改良的等压仪,测定了浓度在1.5mol盐/kg溶液以下乙醇-氯化钙,乙醇-碘化钠,乙醇-醋酸钾,异丙醇-氯化钙、异丙醇-碘化钠等五个系统低于1大气压时的饱和蒸气压,并采用一个单参数方程对实验数据进行了关联。计算结果表明,计算值能较好地与实验值相吻合。