乙醇在正己烷中的解缔与超额焓

测定了不同温度和浓度下乙醇与正己烷液体混合物的热压力系数及内压,并用修正的van der Waals模型关联了这些实验数据,从模型参数B/A2得到了一个乙醇自缔合随组成而遭破坏程度的公式.根据这个公式设想了一个醇与烃的混合模型,建立了混合物的超额焓方程,它能够满意地描述上述混合物的超额焓随组成的变化规律,并显示物理和化学作用对HE的贡献     

含醇溶液的热力学研究I.超额焓模型

提出了一个醇与烃混合的热力学模型，据此，得到了一个简单的超额焓方程， 它由物理和化学贡献两部分组成。这个方程具有一定的通用性，能够推广到其它含 醇溶液。方程不仅能满意地用来描述超额焓与组成间的关系，而且还能显示组分间 的相互作用。     

含醇溶液的热力学研究I.超额焓模型

提出了一个醇与烃混合的热力学模型,据此,得到了一个简单的超额焓方程, 它由物理和化学贡献两部分组成。这个方程具有一定的通用性,能够推广到其它含 醇溶液。方程不仅能满意地用来描述超额焓与组成间的关系,而且还能显示组分间 的相互作用。     

环己酮-醇二元系统超额焓测定和关联的研究

用MS-80型Calvet微热量计首次测定了环己酮＋乙醇、＋正丙醇、＋正丁醇、＋环戊醇、＋环己醇系统在293.15、298.15、303.15及308.15 K四个温度下的超额焓HE,并拟合为平滑方程,拟合方差很小.环己酮和醇组成的二元混合系统的超额焓在全浓度范围内都为正值,其最大值都处在醇浓度为50％附近.超额焓随着醇分子中含碳原子数的增多而增大；超额焓值受温度的影响很大,且随着温度的升高而增大.     

含醇溶液的热力学研究Ⅲ.超额体积

根据先前提出的含醇溶液形成的热力学模型，利用充上和释放两个组分间引力 势能的方法，建立了一个含醇溶液超额体积方程．该方程有清晰的物理意义，不仅 能描述各种各样含醇溶液的超额体积随组成的变化规律，而且还能显示自缔合、交 叉缔合和组分间的van der Waals引力对超额体积的贡献．     

含醇溶液的热力学研究IV.超额Gibbs自由能

利用先前提出的含醇溶液形成的热力学模型，以及释放和充入组分间引力势能 的方法，建立了超额Bibbs自由能方程，它可以避开计及化学作用对超额Gibbs自由 能的贡献，使方程的推导大为简化。这个模型能够联立地用来关联各种含醇溶液， 包括含醇水溶液的超额焓、超额Gibbs自由能和超额熵。对17个有代表性的含醇溶 液关联结果表明，与实验值的一致性是很令人满意的。     

含醇溶液的热力学研究IV.超额Gibbs自由能

利用先前提出的含醇溶液形成的热力学模型，以及释放和充入组分间引力势能 的方法，建立了超额Bibbs自由能方程，它可以避开计及化学作用对超额Gibbs自由 能的贡献，使方程的推导大为简化。这个模型能够联立地用来关联各种含醇溶液， 包括含醇水溶液的超额焓、超额Gibbs自由能和超额熵。对17个有代表性的含醇溶 液关联结果表明，与实验值的一致性是很令人满意的。     

醇类在苯及对二甲苯中过量焓预测

醇类在苯及对二甲苯中过量焓预测裘利言，姚惟馨（南京化工学院应用化学系南京２１０００９）关键词醇，芳烃，缔合，过量焓含醇体系的热力学性质研究近来十分活跃。通常文献所报道的醇－芳烃体系中醇的摩尔分数ｘ＿Ａ在０．１～０．９，而对于极稀溶液区有关报道很少。这...     

含醇溶液的热力学研究Ⅳ.超额Gibbs自由能

利用先前提出的含醇溶液形成的热力学模型,以及释放和充入组分间引力势能的方法,建立了超额Gibbs自由能方程,它可以避开计及化学作用对超额Gibbs自由能的贡献,使方程的推导大为简化.这个模型能够联立地用来关联各种含醇溶液,包括含醇水溶液的超额焓、超额Gibbs自由能和超额熵.对17个有代表性的含醇溶液关联结果表明,与实验值的一致性是很令人满意的.     

癸二醇和十二烷二醇及其混合物的液固相变研究

使用差示扫描量热法（DSC）和红外光谱法（IR）对1，10-癸二醇（1，10-C10H22O2，A）与1，12-十二烷二醇（1，12-C12H26O2，B）及其二元混合物系统液固相变进行研究。测定了该二元混合系统的相变温度、相变焓和液固平衡相图。该二元系统存在低共熔混合物，其组成为xB=0．333，低共熔温度为328K。该二元混合系统的IR图谱显示存在氢键缔合现象，长链烷烃中的亚甲基在晶格中是有序规则排列的。该系统具有较低的相变温度和较高的相变焓，是一种潜在的低温储能材料。     

脂肪族α-氨基酸疏水自缔合作用的流动微量热法研究

建立了水溶液中脂肪族α- 氨基酸疏水自缔合相互作用的化学模型, 根据模型方程对由精密流动微量热法测得的α- 氨基酸水溶液的稀释焓数据进行回归分析, 得到等步自缔合作用的平衡常数(K)、焓变(ΔHm)和熵变(ΔSm)等热力学参数, 发现焓、熵之间存在很好的补偿关系. 同时计算了溶液中水的偏摩尔过量熵(SE1), 并根据脂肪族α- 氨基酸的水化模型对结果进行了讨论. 建立的化学模型参数能在一定程度上解释McMillan- Mayer模型中的同系焓作用系数的物理意义.     

Calculating the thermodynamic properties of aqueous solutions of alkali metal carboxylates

A modified Robinson-Stokes equation with terms that consider the formation of ionic hydrates and associates is used to describe thermodynamic properties of aqueous solutions of electrolytes. The model is used to describe data on the osmotic coefficients of aqueous solutions of alkali metal carboxylates, and to calculate the mean ionic activity coefficients of salts and excess Gibbs energies. The key contributions from ionic hydration and association to the nonideality of solutions is determined by analyzing the contributions of various factors. Relations that connect the hydration numbers of electrolytes with the parameters of the Pitzer-Mayorga equation and a modified Hückel equation are developed.     

Hydration of nonelectrolytes in binary aqueous solutions

Literature data on the thermodynamic properties of binary aqueous solutions of nonelectrolytes that show negative deviations from Raoult’s law due largely to the contribution of the hydration of the solute are briefly surveyed. Attention is focused on simulating the thermodynamic properties of solutions using equations of the cluster model. It is shown that the model is based on the assumption that there exists a distribution of stoichiometric hydrates over hydration numbers. In terms of the theory of ideal associated solutions, the equations for activity coefficients, osmotic coefficients, vapor pressure, and excess thermodynamic functions (volume, Gibbs energy, enthalpy, entropy) are obtained in analytical form. Basic parameters in the equations are the hydration numbers of the nonelectrolyte (the mathematical expectation of the distribution of hydrates) and the dispersions of the distribution. It is concluded that the model equations adequately describe the thermodynamic properties of a wide range of nonelectrolytes partly or completely soluble in water.     

Simultaneous solubility of SO2 and NH3 in (salt + H2O) and enthalpy change upon dilution of (SO2 + NH3 + salt + H2O) in (salt + H2O) {salt = (NH4)2SO4 or Na2SO4}: Experimental results and model predictions

The simultaneous solubility of sulfur dioxide and ammonia in aqueous solutions of (ammonium sulfate or sodium sulfate) was measured by a synthetic method in the temperature range from 313.6 to 373.2 K and at pressures up to 2.5 MPa. Furthermore, the enthalpy change upon diluting aqueous solutions of sulfur dioxide, ammonia and (ammonium sulfate or sodium sulfate) in aqueous solutions of the same salt was measured in a batch calorimeter at about 313 and 352 K. The experimental results are used for comparison with predictions from a thermodynamic model for the vapor–liquid equilibrium and the enthalpy of dilution of those chemical reacting systems. In that model, activity coefficients are calculated from Pitzer's molality-scale-based Gibbs excess energy model, where all interaction parameters are either adopted from previous investigations on the properties of the binary and ternary sub-systems (if available) or they are neglected (if they are not available).     

Enthalpies of Dilution of Aqueous Solutions of NaOH, KOH, and CsOH at 300, 325, and 350°C

Dilution enthalpies, measured using isothermal flow calorimetry, are reported for aqueous solutions of KOH and CsOH at 300°C and 11.0 MPa, 325°C and 14.8 MPa, and for aqueous solutions of NaOH, KOH, and CsOH at 350°C and 17.6 MPa. Previously collected dilution enthalpies for aqueous solutions of NaOH at 300°C and 9.3 MPa and at 325°C and 12.4 MPa were included when fitting the Pitzer parameters. The concentration range of the hydroxide solutions was 0.5–0.02 molal. Parameters for the Pitzer excess Gibbs ion-interaction equation were determined from the fits of the experimental heat data. Equilibrium constants, enthalpy changes, entropy changes, and heat capacity changes for alkali metal ion association with hydroxide ion were estimated from the heat data. For all systems, the enthalpy changes and entropy changes were positive and had accelerating increases with temperature. The resulting equilibrium constants show significant, but smaller, increases with temperature.     

Modeling simple amphiphilic solutes in a Jagla solvent

Methanol is an amphiphilic solute whose aqueous solutions exhibit distinctive physical properties. The volume change upon mixing, for example, is negative across the entire composition range, indicating strong association. We explore the corresponding behavior of a Jagla solvent, which has been previously shown to exhibit many of the anomalous properties of water. We consider two models of an amphiphilic solute: (i) a "dimer" model, which consists of one hydrophobic hard sphere linked to a Jagla particle with a permanent bond, and (ii) a "monomer" model, which is a limiting case of the dimer, formed by concentrically overlapping a hard sphere and a Jagla particle. Using discrete molecular dynamics, we calculate the thermodynamic properties of the resulting solutions. We systematically vary the set of parameters of the dimer and monomer models and find that one can readily reproduce the experimental behavior of the excess volume of the methanol-water system as a function of methanol volume fraction. We compare the pressure and temperature dependence of the excess volume and the excess enthalpy of both models with experimental data on methanol-water solutions and find qualitative agreement in most cases. We also investigate the solute effect on the temperature of maximum density and find that the effect of concentration is orders of magnitude stronger than measured experimentally.     

Enthalpies of Dilution of Aqueous Solutions of LiCl, KCl, and CsCl at 300, 325, and 350°C

Dilution enthalpies, measured using isothermal flow calorimetry, are reported for aqueous solutions of LiCl, KCl, and CsCl at 300°C and 11.0 MPa, 325°C and 14.8 MPa, and 350°C and 17.6 MPa. The concentration range of the chloride solutions was 0.5 to 0.02m. Parameters for the Pitzer excess Gibbs ion-interaction equation were determined from the fits of the experimental heat data. Equilibrium constants, enthalpy changes, entropy changes, and heat capacity changes for ion association of the chloride salts were estimated from the heat data. For all systems, the enthalpy and entropy changes were positive and had accelerating increases with temperature. The resulting equilibrium constants show significant, but smaller, increases with temperature.