固体─超临界流体相平衡的分子热力学模型

从分子热力学基础出发提出一个适用于固体-超临界流体相平衡的理论模型，溶液中溶质的化学位分解为无限稀溶液化学位及溶质浓度效应两部.无限稀溶液化学位由简化的Oz方程计算，其中包括斥力贡献、局部组成及长程引力项浓度对化学位的贡献由作者根据Kirkwood-Buff溶液理论提出的修正Wilson模型计算．用45个二元系862个数据点对此模型进行检验并和PR方程（vdw-2混合规则）计算结果进行比较，本模型的平均绝对误差为11.7％，而PR方程的结果为14.9％，对极性溶剂体系的计算结果有显著改善.用此模型直接推算的萘-Co_2体系萘的偏摩尔焓和文献数据相吻合     

烃类溶质无限稀活度系数的测定和关联

研究溶质进样量、溶剂(固定液)涂复量和载气流速(柱压降)等对色谱法测定溶质无限稀活度系数的影响,提出用通用型气相色谱仪准确测定溶质无限稀活度系数的实验方法,测定了正戊烷、正己烷、正庚烷、环己烷、苯和甲苯等烃类溶质在角鲨烷和正十八烷两种溶剂中,在30℃、50℃和70℃及大气压力下的无限稀活度系数,提出关联溶质无限稀活度系数的基团贡献模型,并定出CH_3、CH_2、CH、CYCH_2、ARCH和ARC基团的参数,用此模型进行无限稀活度系数和非无限稀活度系数的预测,其结果比ASOG模型要好。     

三维溶解度参数和MOSCED模型相结合预测液相活度系数

提出活度系数预测的新方法，用纯物质的一些性质参数按三参数溶解度参数法结合ＭＯＳＣＥＤ模型计算的无限稀释活度系数，选合适的单参数方程求得过量自由焓模型的两个参数，对１１７个二元溶液体系的２２２３个组成点的液相活度系数作了预测。与由文献数据相应方程求得的结果相比，平均相对误差约５％。     

羟基和烃类基团相互作用参数的确定

在以前工作的基础上,进一步用气相色谱法测定了40—80℃含醇体系溶质无限稀活度系数。确定了羟基和烃类基团的相互作用参数。用本文的基团贡献模型和相互作用参数计算活度系数,其结果与实验值符合良好。     

由汽液平衡数据推算溶液粘度的研究

从Ｅｙｒｉｎｇ的粘度理论出发,结合Ｒｏｔｈｅｒ等人的有关假设,提出了一个由汽液平衡数据推算溶液粘度的模型。用该模型,由纯物质粘度和Ｗｉｌｓｏｎ方程参数推算了乙醇 正己烷等九个体系的溶液粘度,计算结果较为满意     

乙醇水溶液中极稀甲醇的蒸发平衡比

用改良的 Rose-Williams 釜测定了乙醇水溶液中极稀甲醇的蒸发平衡比数据,并结合文献中的端极数据,用一个七常数的经验方程进行了关联计算。该方程可推算乙醇水溶液全浓度范围内甲醇的无限稀 K 值。     

含醇溶液中分子扩散系数的分子模拟

利用分子动力学(MD)模拟验证了含醇溶液的无限稀释扩散系数模型和不同浓度溶液的扩散系数模型.选用的溶质分别为甲醇、乙醇、丙醇、异丙醇、正丁醇和甘油,温度为293.15K,压力为0.1MPa.计算结果表明:Dullien和Asfour方程适用于计算甲醇和乙醇溶液的扩散系数DAB;而对于其它醇溶液的扩散系数,Leffler和Cullinan方程较适用.     

多硝基化合物的偶极矩测定

本文根据Debye偶极矩理论,报告了太安、苦味酸、黑索今和α—奥克托金四种多硝基化合物分子偶极矩的测量方法及其实验结果。实验以折射法为基本原理,选用电桥实验装置。将极性溶质溶于非极性溶剂的稀溶液中,在同一温度时分别测定几种不同重量分数浓度溶液的相对介电常数、比容和折射率,通过图解外推法求得几个参数来计算溶质的总克分子极化度和克分子折射度,最后计算溶质的分子偶极矩。实验偶极矩采用Halverstadt-Kumler方程计算。分子偶极矩的实测值与国外文献值一致。实验值在多次测量中的绝对误差为±0.03D;报告中的实验的精度经误差分析,其最大相对误差为±0.4％。     

苯-噻吩-DMF体系汽液平衡的研究(Ⅱ)——气相色谱法测定稀溶液的活度系数

根据 Conder 和 Purnell 提出的有限浓度普遍化保留理论,导出了有限稀释活度系数公式,用气相色谱法测定了苯-DMF 和噻吩-DMF 两个二元体系在稀溶液区的汽液平衡数据。用 Margules方程和 Wilson 方程对测得的汽液平衡数据进行了关联,并与平衡釜测定的汽液平衡数据作了比较,征明可在全浓度范围内用 Wilson 方程推算苯-噻吩-DMF 体系的汽液平衡数据。     

二氧化碳气田气常温闪蒸的实验测定和模拟计算

在含N_2、CH_4、CO_2体系常温汽液平衡(VLE)文献数据的基础上,用扩展的PR方程(MPR)建立了该体系VLE计算模型,计算精度达到压力平均相对偏差0.76％、汽相组成平均绝对偏差0.0018(摩尔分率);用静态法高压VLE测定装置对CO_2气田气在292至299 K温度下作了闪蒸实验测定。并用MPR方程进行模拟计算,计算结果与实验值符合良好。     

On the molecular basis of adsorbed solution behaviour

A theoretical study, based on statistical thermodynamics, of the adsorbed solution behaviour of binary gas monolayers on a homogeneous solid surface is presented. The adsorbate—solid interactions are modelled via the summed 10-4 potential and the adsorbate—adsorbate interactions as those of a two-dimensional fluid mixture in which the molecules interact via Lennard-Jones 12-6 potentials. The thermodynamic properties of the two-dimensional mixture are obtained from the van der Waals one-fluid model. We present results from Monte Carlo computer simulations of two-dimensional fluid mixtures which support the accuracy of this procedure. The model can be used to study the relative importance of adsorbate—solid and adsorbate—adsorbate interactions in determining the adsorbed solution behaviour.Comparisons with experimental adsorption equilibria data for ethane—propane mixtures adsorbed on graphitized carbon black show that the theory gives excellent predictions of the adsorption equilibria, without adjustable parameters. For this system at 298 K and 700 Torr the adsorption selectivity is dominated by the difference in the Henry's law constants. However, it is shown that the adsorbate—adsorbate interactions and nonideal adsorbed solution behaviour become more or less important depending on the conditions in relation to the two-dimensional phase diagram.     

含盐多元体系汽液相平衡数据测定及预测

对甲醇／乙醇/水／NH_4NO_3四元体系中的有关含盐二元汽液相平衡数据进行了测定及关联．提出用化学滴定──色谱分析联合法确定含盐液相组成．关联所得的最佳参数用于该体系三元及四元汽液相平衡数据的预测,并与实验值作了比较．结果表明,预测值与实验值符合良好．     

Modeling aspirin and naproxen ternary solubility in supercritical CO2/alcohol with a new Peng–Robinson EOS plus association model

A new version of the Peng–Robinson equation of state (PR EOS) is developed through the use of Wertheim's thermodynamic perturbation theory of associating fluids and statistical associating fluid theory (SAFT). The new equation is characterized by two temperature-independent parameters, namely, association strength and association volume, which account for the association interactions between associating molecules. In this work, we employed the equation to model aspirin and naproxen solubility enhancement obtained in the ternary supercritical CO₂/alcohol systems, where the original PR EOS has resulted in large and negative binary interaction parameters between the polar solute and polar cosolvent. Calculated results show that the Peng–Robinson EOS plus association model gives better performance to correlate these ternary solubility data over the ranges of temperature, pressure and cosolvent concentration investigated than its conventional form that uses temperature-dependent parameters.     

Nonrandom two-liquid activity coefficient model with association theory

Considered one of the most versatile and widely used classical thermodynamic models to correlate phase equilibria behavior of nonideal systems, the nonrandom two-liquid (NRTL) theory does not explicitly account for specific chemical associations such as hydrogen bonding. This deficiency has been recognized as the cause for unsatisfactory representation of association systems like methanol–alkanes binaries. This work presents a practical approach to integrate Wertheim's perturbation theory for association contribution with the classical NRTL model. Specifically, the association contribution is calculated from pre-determined molecule-specific association strengths while the physical interaction contribution is captured with NRTL binary interaction parameters. The resulting association NRTL model correlates fluid phase equilibria of association systems with few adjustable parameters and offers improved predictive capability for higher order systems.     

Effects of crystal growth rate and heat and mass transfer on solute distribution

The effects of crystal growth rate and heat and mass transfer on solute distribution during solidification of binary melt have been theoretically investigated on the basis of a new theory of solute distribution proposed by the present authors. The solute distribution factor f at the solid-liquid (SL) interface is in inverse proportion to the one-half power of the dimensionless growth rate U. The growth rate U is in proportion to the second power of the normalized concentration difference between the SL interface and bulk melt. A new transport factor K, which describes heat and mass transfer in melt, gives an important contribution to the crystal growth and the solute distribution at the SL interface. The transport factor is used successfully to control the solidification of melt. The flow structure in melt exerts essential influence on the solid purity.     

CORRELATION OF DIFFUSION COEFFICIENTS FOR LIQUIDS AND DENSE FLUIDS WITH TEMPERATURE AND PRESSURE

On the basis of the free volume theory and activation energy concept,a fundamental equation whichtakes into account the effects of temperature and pressure has been developed.By introducing differentexpressions for the free volume and activation energy,several equations for fluid diffusion coefficients were derivedaccordingly.With the van der Waals free volume and intermal energy formula,a three-parameter model for fluiddiffusion coeffficients at moderate pressure was obtained.The grand average absolute deviation percent of 345data points (44 systems)for self-and infinite dilute inter-diffusivities is 2.32,against the results of the model ofCohen and Turnbull,4.13.In particular,by means of the modified Carnahan-Starling free volume equation,afour-parameter model with average abosolute deviation percent 2.64(30 systems,644 data points)for theestimation of dense fluid inter-and self-diffusivities at high pressures and in supercritical conditions was derived.The derived model is superior to the method of L     

Dimensional analysis of the detergency process for systems containing multicomponent soils

Dimensional analysis of the detergency process has been extended from soil-surfactant systems which contain a single polar soil to those with binary and ternary component soils which contain a nonpolar ingredient. This was made possible by replacement of the soil dipole moment variable by the proportional square root of orientation polarization (P_o) and by establishment of the validity of the empirical volume fraction additivity of the ingredient P₀ values of binary polar—polar mixtures by using the classical dilute solution—solute (P₂) extrapolation procedure with a chemical oscillometer.     

Metabolic network modelling: Including stochastic effects

We propose to model the dynamics of metabolic networks from a systems biology point of view by four dynamical structure elements: potential function, translocation matrix, degradation matrix, and stochastic force. These four elements are balanced to determine the network dynamics, which gives arise to a special stochastic differential equation supplemented by a relationship between the stochastic force and the degradation matrix. Important network behaviors can be obtained from the potential function without explicitly solving for the time-dependent solution. The existence of such a potential function suggests a global optimization principle. The existence stochastic force corresponds naturally to the hierarchical structure in metabolic networks. We provide theoretical evidences to justify our proposal by discussing its connections to others large-scale biochemical systems approaches, such as the network thermodynamics theory, biochemical systems theory, metabolic control analysis, and flux balance analysis. Experimental data displaying stochasticity which carries important biological information are also pointed out.