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。     

葡萄糖与醇在甲酰胺溶液中的焓相互作用参数

利用量热法测定了298.15K时葡萄糖在一些醇(甲醇、乙醇、1-丙醇、1-丁醇)与甲酰胺的混合溶剂中的溶解热.采用McMilan-Mayer方法,将溶液热力学过量性质与溶液中粒子的相互作用参数相关联,求得了粒子间的焓对相互作用参数和三分子相互作用参数,并就溶质-溶质间的相互作用及溶剂的影响进行了讨论.     

Enthalpy of Solution of Terfenadine in Different Solvents

Enthalpies of solution of various terfenadine samples in methanol and in ethanol were measured. Samples were prepared by crystallization in different solvents. The calorimetric results give important information on crystal structure of the terfenadine forms and on the solute/solvent interactions of this compound with the solvents.This revised version was published online in November 2005 with corrections to the Cover Date.     

Enthalpy of Solution of Glycine at Various pHs

A new approach to determination of the enthalpies of solution of amino acids in multicomponent solutions at various pHs is proposed. The approach allows correct estimation of the contribution of acid-base processes occurring in the system and, therefore, correct interpretation of experimental data with regard to interactions between components of the investigated systems. The approach is checked for consistency with an example of glycine.     

Simple System for Oxidation of Alcohols in Aqueous Solution

A simple and mild system for conversion of primary and secondary alcohols to corresponding aldehydes and ketones has been developed using aqueous sodium dichloroiodate at room temperature in water. This novel application of aqueous sodium dichloroiodate gives high yield and offers a number of advantages in terms of safety and ease of use in comparison to other methods that often employ toxic and hazardous solvents and materials.     

The Enthalpy of Solution in Water of Complexes of Zinc with Methionine

The enthalpies of solution in water of L--methionine and its zinc complexes Zn(Met)Cl₂, Zn(Met)₂Cl₂·2H₂O, Zn(Met)(NO₃)₂·1/2H₂O, Zn(Met)₃(NO₃)₂·H₂O and Zn(Met)SO₄·H₂O have been measured at 298.15 K. The standard enthalpy of formation of met(aq) has been calculated. The experimental results have been discussed.This revised version was published online in November 2005 with corrections to the Cover Date.     

The Enthalpy of Solution in Water of Histidine Complexes of Re Nitrates

The enthalpies of solution in water of RE(His)(NO₃)₃H₂O (RE=La—Nd, Sm—Lu, Y) were measured calorimetrically at 298.15 K, and the standard enthalpies of formation of RE(His)_aq³⁺ (RE=La—Nd, Sm—Lu, Y) were calculated. The plot of the enthalpies of solution vs. the atomic numbers of the elements in the lanthanide series exhibits the tetrad effect.This revised version was published online in November 2005 with corrections to the Cover Date.     

氯化钙/水-醇溶液稀释热

电解质溶液稀释热是溶液的重要热性质之一．由它可计算不同浓度下电解质的溶解热、表现相对摩尔焓、溶液中反应热和化合物生成热等．在电解质溶液理论研究中，稀释热也是重要的基础数据．由稀释热可推算溶液中组分的活度系数、渗透系数、相对偏摩尔焓及表观摩尔热容等[1-3]．在化工生产中，稀释热是化工过程能量计算不可缺少的数据．电解质水溶液稀释热已有不少研究[2，4]．但电解质混合溶剂体系稀释热报导甚少．随着加盐精馏技术、海水淡化技术等研究的进展，急需这方面数据．本文作者已报告了CaCl2／C2H5OH－H2O体系[5]和CaCl2／n－C…     

Termochemistry of Aniline Solution in Mixtures of Alcohols with Dihexyl Ether

The heats of solution of aniline and cyclohexane in mixtures of methanol, 1-butanol, and 1-octanol with dihexyl ether at 25°C in the entire range of compositions of the mixed solvents were measured. The enthalpies of transfer of aniline and cyclohexane from dihexyl ether to its mixtures with alcohols were calculated. It was suggested that, in methanol-based systems, the major factor is the interaction of the alcohol as an acid with aniline as a base, whereas in butanol- and octanol-based system the larger contribution is made by the interaction of the alcohol as a base with aniline as an acid.     

肌醇在氯化钠水溶液中的稀释焓和焓对相互作用

应用微量热法测定了298.15K时肌醇在纯水和氯化钠水溶液中的稀释焓,根据McMillan-Mayer理论计算了肌醇在不同浓度的氯化钠溶液中的2到4阶焓相互作用系数.结果表明,肌醇在氯化钠溶液中的焓对相互作用系数h2均为负值,并且随着氯化钠浓度的增大,h2的值呈增大趋势.根据溶质-溶质相互作用和溶质-溶剂相互作用对焓对相互作用系数的变化趋势进行了解释.     

Effect of Short Chain Alcohols upon Viscosity of TTAB Solution

The effect of ethanol (C2H5OH), propanol (C3H7OH), and butanol (C4H9OH) upon the viscosity of tetradecyltrimethylammonium bromide (TTAB) solution in the presence or absence of KBr at 30 o C was investigated, where the surfactant concentration CS is kept constant. In the absence of KBr, the relative viscosity ηr of TTAB solution increases linearly with the alcohol concentration CA, indicating that the alcohols do not promote micelle formation of TTAB. In the presence of KBr, ′r linearly decreases with CA for C2H5OH, but it exhibits a maximum with increasing CA for C3H7OH or C4H9OH. The facts reveal that C2H5OH or C4H9OH promotes the micelle formation of TTAB. A possible explanation is that the hydrophobicity of the micellar interior is enhanced by KBr, so that C2H5OH or C4H9OH can dissolve in micelle and promotes micelle formation. In the presence of KCl, which is less efficient in promoting the micelle formation of cationic surfactant, both C3H7OH and C4H9OH have only a slight effect on the micelle formation. In contrast, due to the hydrophilicity, C2H5OH cannot dissolve in micelles in the presence of KBr or KCl.     

溶解量热法测三氧化钼标准生成焓

用溶解量热法,以KIO_4和KOH组成的弱碱性溶液为量热溶剂,设计3个不同的热化学循环,用RD-1型热导式自动量热计测定了MoO_3的标准生成焓,并推荐其值为ΔH_(t(moO_3))~0(298.15K)=-765.0±6.8kJ·mol~(-1)。     

Thermochemistry of Aniline Solution in Isomeric Butyl Alcohols and Their Aqueous Solutions

The enthalpies of solution (_s H ⁰) of aniline in isomeric butyl alcohols and their aqueous solutions at 25°C were determined. The dissolution of aniline becomes more endothermic with increasing content of alcohol in aqueous solution. The enthalpy coefficients of pair interaction alcohol-aniline in aqueous solution were calculated. This interaction is enhanced in the order tert-butanol-sec-butanol-iso-butanol-n-butanol. The correlations of these characteristics with physicochemical properties of solvents were revealed.     

三种氨基酸从水到DMSO水溶液的迁移焓研究

用微量量热法测定甘氨酸、L-丙氨酸、L-丝氨酸在二甲基亚砜(DMSO)水溶液中的溶解焓, 计算得到三种氨基酸从水到DMSO水溶液的迁移焓, 根据共球交盖模型对氨基酸与DMSO在水溶液中的相互作用进行讨论, 并与前期的氨基酸在尿素水溶液体系中的迁移焓进行比较. 结果显示, 氨基酸与共溶剂分子之间产生的静电相互作用以及亲水-亲水相互作用对氨基酸迁移焓有负贡献, 而亲水-疏水、疏水-疏水相互作用对氨基酸迁移焓有正贡献. 与尿素水溶液中氨基酸迁移焓的绝对值随尿素浓度的增加而增加, 并规律性地出现多个变化点的情况不同, 氨基酸从水到DMSO水溶液的迁移焓随DMSO浓度的增加而线性增加. 这种差异反映了尿素与DMSO及其水溶液结构的不同, 为认识尿素在水溶液中的缔合作用提供了对比依据.     

Enthalpy Characteristics of Solution and Solvation of CuCl2 in Water-Acetonitrile Mixtures at 298.15 K

Thermochemical characteristics of solution of copper(II) chloride were found from calorimetricdata, values describing solvation processes in a water-acetonitrile mixed solvent were calculated for theentire range of compositions. Enthalpy characteristics of solvation of individual Cu^{2 +} ions in water-aceto-nitrile mixtures were found and analyzed.     

Solvent Effect on the Partial Molar Volume and the Enthalpy of Solution of Gallium Chloride

Partial molar volumes and heats of solution were determined for gallium chloride in benzene, toluene, o-xylene, mesitylene, 1,2-dichloroethane, ethyl acetate, acetonitrile, and 1,4-dioxane. A proportionality in changes in these characteristics is observed for weak ,-type complexes in alkylbenzene medium. The partial molar volumes of strong n,-type complexes approach a limiting value.     

离子液体[C2mim][GaCl4]的溶解热研究

在干燥氩气氛下, 用等摩尔的高纯无水GaCl3和[C2mim][Cl](氯化1-甲基-3-乙基咪唑)直接搅拌混合, 制备了淡黄色透明的的离子液体[C2mim][GaCl4] (1-ethyl-3-methylimidazolium chlorogallate) . 在298.15 K下, 利用具有恒温环境的溶解反应热量计, 测定了这种离子液体的不同浓度摩尔溶解焓 . 针对[C2mim][GaCl4]溶解于水后即分解的特点, 在Pitzer电解质溶液理论基础上, 提出了确定这种离子液体标准摩尔溶解焓的新方法, 得到了[C2mim][GaCl4]在水中的标准摩尔溶解焓, ＝－132 kJ•mol－1, 以及Pitzer焓参数组合: ＝－0.1373076和 ＝0.3484209. 借助热力学循环和Glasser离子液体晶格能理论, 用Ga3＋, Cl－和[C2mim]—的离子水化焓数据以及本文得到的[C2mim][GaCl4]标准摩尔溶解焓, 估算了配离子4Cl－(g)解离成Ga3＋(g)和4Cl－(g)的解离焓ΔHdis([GaCl4]-)≈5855 kJ•mol－1. 这个结果揭示了离子液体[C2mim][GaCl4]的标准摩尔溶解焓绝对值并不很大的原因, 即是很大的离子水化焓被很大的[GaCl4]－(g)的解离焓相互抵消了.     

Excess Enthalpy Data in Some Binary Systems Containing Non Electrolyte Solution and Their Correlations at 298.15K

Abstract

Excess enthalpy data measured at 298.15K were collected from the literature. The data contains 48 binary systems (812 data points). The experimental data were correlated by Redlich-Kister equation. In this work the following thermodynamics models were also tested. Wilson, NRTL models: and their parameters were calculated. A modified NRTL with a composition-dependent (α₁₂) parameter was also proposed. The correlation of excess enthalpy data in the systems using this model provides good results.     

不同结晶度的乙二醇及其水溶液玻璃化转变与焓松弛

为了考察晶体成分对无定形成分玻璃化转变和结构松弛行为的影响,利用差示扫描量热法(DSC),结合低温显微技术,研究了乙二醇(EG)及其50％水溶液在不同结晶度时的玻璃化转变和焓松弛行为.采用等温结晶方法控制骤冷的部分结晶玻璃体中的晶体份额.DSC结果表明,对于部分结晶的EG,只有单一的玻璃化转变过程,而对于50％EG,当结晶度不同时,不同程度地表现出两次玻璃化转变（无定形相Ⅰ和无定形相Ⅱ）.相Ⅰ的玻璃化转变温度和完全无定形态的含水EG的玻璃化转变温度相一致;相Ⅱ的玻璃化转变温度要比此温度约高6 ℃.低温显微观察结果印证了DSC实验结果.DSC等温退火的实验和KWW(Kohlrausch-Williams-Watts)衰变函数分析结果表明,EG无定形和50％EG中的两种无定形有不同的焓松弛行为.