在汽液平衡中由T、p、x数据推算y的样条函数法(Ⅱ)三元系

采用模拟平板弯曲变形的曲面样条函数表达三元系过量自由焓函数Q,由此建立了一个在汽液平衡中由T、p、x数据推算y的间接算法.非线性方程组的求解采用Broyden改进的Newton—Raphson迭代程序,经过30个从接近理想到高度非理想的不同类型三元系的检验结果表明,本方法计算结果可靠,与实验值符合良好.本方法还具有算法稳定、对初值要求不高及收敛速度快、过量性质影响小等特点.     

The mixing criterion in crystallization by cooling

In processes where mass flows have to be mixed, and the formation of new phases has to be prevented, it is essential for the composition and enthalpy (J/kg) to be so adjusted to each other that, whatever the mixing ratio, the ultimate mixture will consist of one single phase under physical equilibrium conditions (temperature and pressure).The requirements imposed on the composition and enthalpy will be called the mixing criterion.The mixing criterion plays an important role in technical crystallization processes involving mixing — frequently under adiabatic conditions — of liquid flows differing in temperature and/or concentration.For a binary system and a ternary one, both containing one component that can be crystallized, the authors determined the conditions under which supersaturation and its consequences (scaling and undesired nucleation) can be avoided during adiabatic mixing of the feed and the mother liquor in a draft-tube baffled (D.T.B.)-crystallizer.The correctness of the theory is confirmed by the results of runs conducted with a ternary system in a 100 l. experimental crystallizer; compliance with the mixing criterion proved to prevent scaling, and to increase the average crystal size by a factor of 3·5.     

Thermodynamics of associated solutions—I: Alcohol-inert solvent solutions

For alcohol-aliphatic hydrocarbon solutions, the athermal associated solution theory of Wiehe and Bagley is modified by introducing a physical interaction term of the Scatchard—Hildebrand type expression. Good fits between the modified theory and experimental data for the excess Gibbs free energy of mixing, G^E, the excess enthalpy of mixing, H^E, and the excess volume of mixing, V^E are obtained. The parameters involved in G^E and H^E expressions are either a characteristic of the alcohol or calculable using the proposed correlations and pure component properties.     

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％。     

Excess enthalpy data for the ternary system methane—ethylene—carbon dioxide by flow calorimetry

Excess enthalpy data for the ternary system methane – ethylene – carbon dioxide was obtained utilizing an isothermal flow calorimeter. The measurements were made at three temperatures: 293.15, 305.15 and 313.15 K and pressures of 1.114, 1.520 and 3.445 MPa (11, 15 and 34 atm). The determination of excess enthalpies for the binary systems methane—ethylene, ethylene—carbon dioxide and methane—carbon dioxide has been reported in three preceeding articles, respectively: Gagné et al., 1985; Ba et al., 1979 and Barry et al., 1982a. The binary interaction coefficients k_ij obtained for these systems have been utilized as initial values for the optimization procedure leading to the k_ij for the ternary system. For the case of the ternary system studied in this investigation, two types of binary interaction coefficients k_ij have been determined from experimental data: k_ij independent of temperature and pressure and k_ij adjusted as function of temperature and pressure. Experimental data were compared with the predictions from Benedict—Webb—Rubin and Redlich—Kwong equations of state. In both cases, the coefficients k_ij dependent on temperature and pressure led to better prediction of excess enthalpies.     

助表面活性剂对乙草胺微乳液相图的影响

用拟三元相图法研究了醇醚糖苷(AEG)/醇醚羧酸盐(AEC)/醇/乙草胺/水体系的微乳液相行为,讨论了不同碳链长度的醇对乙草胺微乳液拟三元相图的影响,并通过电导率测定,研究了乙草胺微乳液的微观结构转变。结果表明,随着助表面活性剂醇碳链的增长,乙草胺微乳液的微乳区面积逐渐变小,而液晶区从无到有并逐渐增大;以正丁醇为助表面活性剂时,正丁醇的质量分数〔m(正丁醇)/m(AEG+AEC+正丁醇)〕对微乳区面积有一个最佳值。     

醇对乙草胺微乳液相图的影响

用拟三元相图法研究了醇醚糖苷（AEG）/醇醚羧酸盐（AEC）/醇/乙草胺/水体系的微乳液相行为,讨论了不同链长的醇对乙草胺微乳液拟三元相图相图的影响,并通过电导率测定研究了乙草胺微乳液的微观结构转变。结果表明：随着助表面活性剂醇碳链的增长,乙草胺微乳液的微乳区面积逐渐变小,而液晶区从无到有并逐渐增大;固定醇的种类为正丁醇时,醇的含量对微乳区面积有一个最佳值。     

甲苯－乙醇－正己烷（四氯化碳）三元体系过量焓

使用流动式微量热计测量了２９８．１５Ｋ下甲苯－乙醇－正己烷和甲苯－乙醇－四氯化碳两组三元体系以及正己烷－乙醇、乙醇－甲苯、正己烷－甲苯、四氯化碳－甲苯和四氯化碳－乙醇五组二元体系过量焓，对实测数据进行了关联，并计算了全浓度范围内过量焓，绘制了三元体系的等过量焓图。     

甲苯－乙醇－正己烷（四氯化碳）三元体系过量焓

使用流动式微量热计测量了２９８．１５Ｋ下甲苯－乙醇－正己烷和甲苯－乙醇－四氯化碳两组三元体系以及正己烷－乙醇、乙醇－甲苯、正己烷－甲苯、四氯化碳－甲苯和四氯化碳－乙醇五组二元体系过量焓，对实测数据进行了关联，并计算了全浓度范围内过量焓，绘制了三元体系的等过量焓图。     

Prediction of excess free energies of liquid mixtures containing aromatic hydrocarbons using a group solution model

The group solution model of Ratcliff and Chao for the excess free energies of liquid mixtures has been tested and found satisfactory for six mixtures of alcohols and aromatic hydrocarbons. The model was tested by comparing experimental and predicted vapor-liquid equilibrium data. The assumption that aliphatic and aromatic carbon atoms are equivalent appears satisfactory for the mixtures considered. Group contribution functions were generated from experimental data on ethanol/benzene mixtures at 45°C, and are presented. These functions allow the prediction of excess free energies of mixtures containing alcohols and aromatic hydrocarbons at 45°C. No experimental data is required. Predictions at temperatures close to 45°C, using the same functions, should be satisfactory. The group contribution functions were close to those generated previously from alcohol/alkane data. The latter may be used for predicting excess free energies of alcohol/aromatic hydrocarbon mixtures with little loss of accuracy.     

A Thermoanaerobacter ethanolicus secondary alcohol dehydrogenase mutant derivative highly active and stereoselective on phenylacetone and benzylacetone

The secondary alcohol dehydrogenase from Thermoanaerobacter ethanolicus 39E (TeSADH) is highly thermostable and solvent-stable, and it is active on a broad range of substrates. These properties make TeSADH an excellent template to engineer an industrial catalyst for chiral chemical synthesis. (S)-1-Phenyl-2-propanol was our target product because it is a precursor to major pharmaceuticals containing secondary alcohol groups. TeSADH has no detectable activity on this alcohol, but it is highly active on 2-butanol. The structural model we used to plan our mutagenesis strategy was based on the substrate's orientation in a horse liver alcohol dehydrogenase*p-bromobenzyl alcohol*NAD(+) ternary complex (PDB entry 1HLD). The W110A TeSADH mutant now uses (S)-1-phenyl-2-propanol, (S)-4-phenyl-2-butanol and the corresponding ketones as substrates. W110A TeSADH's kinetic parameters on these substrates are in the same range as those of TeSADH on 2-butanol, making W110A TeSADH an excellent catalyst. In particular, W110A TeSADH is twice as efficient on benzylacetone as TeSADH is on 2-butanol, and it produces (S)-4-phenyl-2-butanol from benzylacetone with an enantiomeric excess above 99%. W110A TeSADH is optimally active at 87.5 degrees C and remains highly thermostable. W110A TeSADH is active on aryl derivatives of phenylacetone and benzylacetone, making this enzyme a potentially useful catalyst for the chiral synthesis of aryl derivatives of alcohols. As a control in our engineering approach, we used the TbSADH*(S)-2-butanol binary complex (PDB entry 1BXZ) as the template to model a mutation that would make TeSADH active on (S)-1-phenyl-2-propanol. Mutant Y267G TeSADH did not have the substrate specificity predicted in this modeling study. Our results suggest that (S)-2-butanol's orientation in the TbSADH*(S)-2-butanol binary complex does not reflect its orientation in the ternary enzyme-substrate-cofactor complex.     

EXCESS ENTHALPIES OF 3-METH YLPHENOL - n - HEPTANE, 3-METH YLPHENOL - PHENOL -n- HEPTANE AND 3-METHYLPHENOL- 1-HEXANOL-n-HEPTANE AT 318·15 K

Excess molar enthalpies H^E for two ternary systems, 3-methylphenol-phenol-n-heptane and 3-melhylphenol-1-hexanol-n-heptane and a constituent binary 3-methylphenol-n-heptane have been measured with Calvet-type microcalorimeter at 318·15 K. For predicting ternary excess enthalpies, the modified Redlich-Kister equation was used. It has been shown that the second ternary system exhibits regions of both exothermic and endothermic mixing, and due to the intricated interaction between phenols and alcohols predicting of ternary excess enthalpies with the Redlich-Kister equation is unsuccessful.     

三元非共沸混合制冷剂热力性质算法

为了确保计算的精确性,文中采用PRHV与Lee-Kesler-P lǒcker(LKP)模型相结合的方法计算混合工质汽液相平衡参数与焓、熵等热物理性质,即利用Huron-V idal混合规则,采用立方型PR方程和过量G ibbs自由能NRTL模型相结合的PRHV模型预测相平衡参数,在此基础上,由LKP多参数状态方程计算的焓、熵等状态参数。文中验证了这种预测方法的可靠性与准确性,此方法可作为系统循环模拟计算中相平衡及热力参数的精确计算方法。     

On the application of GE models to high-pressure vapor—liquid equilibrium calculations

This paper demonstrates that the two excess Gibbs free energy G^E models with temperature-dependent parameters in the modified Huron—Vidal first-order (MHV1) mixing rule allow the Peng—Robinson equation of state modified by Stryjek and Vera (PRSV) to be used for calculation of vapor—liquid equilibria over wide ranges of temperature and pressure. Good results are obtained for strongly non-ideal binary and ternary systems.     

Extrapolation of ternary excess thermodynamic properties

A method, based on the Gibbs-Duhem equation, is proposed for extrapolating ternary excess thermodynamic properties over the complete concentration range. For those thermodynamic properties whose three excess partial molal quantities at a given composition can be directly evaluated from a single measurement, such as excess Gibbs free energy of mixing, 4 ternary experimental points are required. For those thermodynamic properties whose three excess partial mólal quantities at a given composition cannot be directly evaluated from a single measurement, such as excess enthalpy of mixing, 7 ternary experimental points are required. In both cases necessary binary data are assumed to be available. Experimental heat of mixing data for the systems ethanol-n-heptane, n-heptane-benzene and ethanol-n-heptane-benzene at 25°C. are also reported.     

三元体系汽液平衡数据的热力学一致性逐点检验

用曲面样条函数表达三元ＶＬＥ体系过量自由焓Ｑ函数，非线性方程组用Ｂｒｏｙｄｅｎ改进的ＮｅｗｔｏｎＲａｐｈｓｏｎ法求解，对１６个不同类型三元ＶＬＥ体系的检验表明，本方法具有计算结果可靠，算法稳定，对初值要求不高及收敛速度快等特点，为三元ＶＬＥ数据的热力学一致性逐点检验提供了一种有价值的方法。     

Associating lattice cluster theory and application to modeling oleic acid + formic acid + formoxystearic acid

The associating lattice cluster theory (ALCT) is developed in this work. It is especially useful for describing mixtures of oligomers of varying architecture. As the influence of the structure is predicted, it can also be applied in cases in which pure component data are lacking. ALCT is used here for the calculation of liquid–liquid equilibria (LLE) in the system oleic acid (OA) + formic acid (FA) + formoxystearic acid that is interesting for biopolymer production. Experimental studies of LLE in that system were carried out at 296, 313, and 333 K. Ternary mixtures were prepared from the educts OA and FA using heterogeneous acidic catalysis. Quantitative NMR spectroscopy was applied for the analysis. For the educt system also the excess enthalpy was studied by isothermal titration calorimetry. The prediction of the ternary LLE by ALCT succeeds. © 2018 American Institute of Chemical Engineers AIChE J, 65: 783–791, 2019     

Effect of self-association on liquid—liquid equilibria. Correlation of mutual solubility for methanol—saturated hydrocarbon systems

The continuous linear association model of the Kretschmer—Wiebe type is used to examine the effects of self-association on liquid-liquid equilibria. The results of the calculation show that the self-association enhances the phase separation and decreases the mole fraction of the self-associating component in a binary mixture at the critical solution point. The application of the theory to the binary systems of methanol—saturated hydrocarbons has yielded good correlations for both the critical solution points and the mutual solubilities at temperatures below the critical. The values of the association constant and enthalpy obtained for methanol are 1030 at 25°C and ?3·5 kcal/mol, respectively. The temperature dependence of the physical interaction parameter for each hydrocarbon is represented by a reduced form. The applicabilities of the theory to both vapour—liquid and liquid—liquid equilibria are better than those of NRTL equation for the systems of methanol—saturated hydrocarbons.     

液体混合物的过量焓热力学模型

引言在溶液现象的研究中,过量焓是一个重要的热力学量,它反映了液体混合物偏离理想溶液的程度．由于能精确地测量,故能否确切地描述这个热力学量,已成为鉴定溶液理论的重要指标．对于简单的小分子液体混合物,过量焓已可由计算机模拟、微扰理论和状态方程来预测．但对于复杂分子构成的液体混合物,特别是有化学作用的系统,上述理论尚不够成熟,通常多用溶液的化学理论来描述．这种理论最早由Dolezalek提出,后经Kretschmer、Renon、Stokes、Chen、Nagata和Heintz等人进一步发展．虽然它已能满意地描述液体混合物的过量焓,但是,迄…