碳酸丙烯酯与1,2-丙二醇二元体系UNIQUAC模型参数的估算与实验修正

在碳酸二甲酯的转酯化工艺过程模拟、设计与优化研究中,缺少与碳酸丙烯酯(PC)和1,2-丙二醇(PG)二元体系相关的相平衡实验数据及UNIQUAC模型参数。今通过实验数据推算和基团贡献法估算两种方法进行了PC和PG二元体系的UNIQUAC模型参数的估算;利用自行设计的汽液平衡装置实验测定了该二元体系的常压汽液平衡数据,通过绘制T-x-y曲线对比对估算结果的准确性进行验证,结果显示实验数据推算办法获得的UNIQUAC模型参数精度较高;最后借助流程模拟软件Aspen Plus,通过数据回归对该二元体系的UNIQUAC模型参数进行了修正,使用修正后的UNIQUAC模型参数对PC和PG二元体系汽液平衡的温度、液相PC摩尔分数和气相PC摩尔分数计算的平均绝对偏差分别是0.5、0.0124%和2.3035%,表明修正后的UNIQUAC模型参数能够用于高精度要求的工艺过程模拟计算。     

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。     

用修正的UNIFAC模型参数及HVOS规则预测汽液平衡

利用Orbey和Sandler提出的HVOS混合规则,PR状态方程与Larsen的活度系数模型相结合建立了无限压力下汽液平衡模型,模型给定状态方程中不随温度变化的参数C*=-0.623 23。用大量的汽液平衡数据在广泛的温度范围内修正了12组MLUNIFAC基团相互作用参数,并用修正的和原始的参数分别对含醇、酸、酮、水、腈和胺等极性二元体系进行了预测。结果表明,体系预测精度显著提高,大部分体系汽相组成的绝对偏差低于4.00×10-2,压力的相对偏差低于6.00%。     

UNIFAC模型关联碳酸酯合成体系的汽液平衡

利用UNIFAC模型对甲醇氧化羰基合成碳酸二甲酯(DMC)体系中的各组分及DMC与苯酚酯交换合成碳酸二苯酯(DPC)体系中的各组分进行了基团划分.根据实验测定的甲醇-DMC、甲醇-草酸二甲酯(DMO)、DMC-DMO、甲醇-苯酚、DMC-苯酚五组二元物系等温汽液平衡数据,拟合了新基团-OCOO-和其他基团间的UNIFAC相互作用参数,扩充了UNIFAC模型的应用范围.与原基团划分的UNIFAC模型关联结果比较,采用新基团划分法推算得到的汽液平衡数据的计算值与实验值偏差较小,说明新基团划分更合理.     

UNIFAC基团贡献法预测混合制冷剂的气液相平衡

将UNIFAC基团贡献法成功地应用于HFCs混合制冷剂的气液相平衡热力学性质的预测.根据资料拟合得到了CH₂、CF₂、F三个主基团的相互作用参数, 用拟合的基团相互作用参数预测了新工质对R32/R227ea、R227ea/R134a和R152a/R227ea及三元混合制冷剂R32/R125/R134a的气液相平衡数据,并与实验进行了对比,两者基本吻合.本工作为今后HFCs混合制冷剂替代和制冷系统研究提供了极有推广价值的物性计算方法和数据,满足了新工质工程设计的要求.     

Calculation of solubilities of the pesticides diuron and monuron in organic nonelectrolyte solvents using UNIFAC and modified UNIFAC (dortmund) models

The solubility of diuron (3‐(3,4‐dichlorophenyl)‐1, 1 ‐dimethyl urea) and monuron (3‐(4‐chlorophenyl)‐1, 1 ‐dimethyl urea) in 49 and 43 different organic non‐electrolyte solvents, respectively, have been calculated. It was found that Modified UNIFAC described well the solubilities both in polar solvents like alcohols, ketones, esters and ethers and in nonpolar solvents like alkanes and aromatic hydrocarbons. UNIFAC and the mobile order theory supplement each other well in calculating the solubilities, which means that one can choose the right model depending on the solvent one is using.     

Isobaric vapor liquid equilibrium in binary mixtures of α-pinene,limonene and 1, 8-cineole

Isobaric vapor liquid equilibrium at atmospheric pressure has been determined for binary mixtures of (–) α-pinene, (+)-limonene and 1, 8-cineole. The Margules and Var Laar equations as well as the models proposed by Wilson, by Renon and Prausnitz (NRTL) and by Abrams and Prausnitz (UNIQUAC) were used to correlate the experimental data. The corresponding parameters for two binaries are reported here.     

Solubilities of anthracene,fluoranthene and pyrene in organic solvents: Comparison of calculated values using UNIFAC and modified UNIFAC (Dortmund) models with experimental data and values using the mobile order theory

The solubility of anthracene in 43 organic solvents, fluoranthene (45 solvents) and pyrene (30 solvents) has been calculated using UNIFAC and Modified UNIFAC (Dortmund) models to estimate the activity coefficient of the solute. It was found that both UNIFAC and Modified UNIFAC described better the solubilities in polar solvents like alcohols, ketones, esters and ethers than in nonpolar solvents like alkanes and aromatic hydrocarbons. UNIFAC and the Mobile Order Theory supplement each other well in calculating the solubilities, which means that one can choose the right model depending on the solvent one is using.     

甲醇、碳酸二甲酯、草酸二甲酯二元体系汽液平衡测定与关联

采用液上气相色谱法测定了一氧化碳低压气相催化合成碳酸二甲酯过程中3组二元物系甲醇-碳酸二甲酯、甲醇-草酸二甲酯、碳酸二甲酯-草酸二甲酯的等温汽液平衡数据。选用W ilson、NRTL、UNIQUAC活度系数方程进行了关联,利用关联出的模型参数计算相应的汽相组成,并与实验值比较,二者符合较好。     

Influence of polymer molecular weight on selected thermodynamic properties of polymer/solvent systems and the application of the UNIFAC theory

The intrinsic viscosities of eleven narrow molecular weight distribution polystyrene samples ranging from number-average molecular weight 1820 to 1 292 000 have been determined in pure solvents of tetrahydrofuran and chloroform with a Ubbelohde No. 1 viscometer at 25°C. By combining the original and modified Fox-Flory viscosity treatments, respectively, with the Flory-Huggins Lattice theory, the interaction parameters were calculated. With the aid of original and modified UNIFAC methods the solvent activity, clustering function of the solvent, and the interaction parameter were computed and compared with the experimental data. It was established that the influence imposed by the polymer molecular weight on the activity of the solvent, the clustering function of solvent, and interaction parameter is insignificant. The modified UNIFAC method satisfactorily predicted the solvent activity as illustrated by previous investigators. However, both UNIFAC methods failed to predict the interaction parameter.     

Vapor-liquid equilibrium,excess gibbs energy and excess enthalpy of 1, 3 dioxolane-methylcyclohexane at t = 313.15 k

Data on vapor-liquid equilibrium and enthalpy of mixing H^E are, obtained for the mixture 1, 3 dioxolane-methylcyclohexane at 313.15 K (40.0°C). Correlation of the data is given by using Redlich-Kister expressions and the excess functions G^E = RT(X₁ In γ₁ + X₂ In γ₂) and TS^E = H^E - G^E are thereby calculated. A comparison is made between this mixture and those formed by 1, 3 dioxolane with cyclohexanol and cyclohexanone.