二元体系C6H6-DMF在293.15 K下的体积性质

利用Anton Paar DMA4500振动管密度计, 测量了293.15 K时二元体系C6H6-DMF(苯-N,N-二甲基甲酰胺)溶液的密度, 利用最小二乘法确立了溶液密度与组成的函数关系. 利用密度数据分别计算了二元体系中C6H6和DMF的表观摩尔体积, 并利用非线性最小二乘拟合法, 分别拟合得到了优化的C6H6和DMF的表观摩尔体积和摩尔分数的函数关系, 以及C6H6和DMF的表观摩尔体积和质量分数的函数关系. 通过对函数关系的极限运算得到了C6H6和DMF的标准偏摩尔体积和摩尔体积. 此外, 还计算了不同组分下体系的超额摩尔体积, 数据可用四参数Redlich-Kister方程很好地关联拟合, 得到方程系数及体系的超额摩尔体积极值位置.     

293.15K时咪唑醋酸盐-乙醇二元体系的体积性质及分子间相互作用简

用比重瓶法测定了293.15 K时1-甲基咪唑醋酸盐([Mim]Ac)/1,3-二甲基咪唑醋酸盐([Mmim]Ac)/1-乙基-3-甲基咪唑醋酸盐([Emim]Ac)-乙醇(EtOH)二元体系在全组成范围内的密度. 计算出[Mim]Ac/[Mmim]Ac/[Emim]Ac和EtOH的表观摩尔体积和体系的超额摩尔体积. 用三参数多项式关联拟合了表观摩尔体积与摩尔分数的关系,外推出组分的极限偏摩尔体积和摩尔体积. [Mim]Ac/[Mmim]Ac/[Emim]Ac和EtOH的摩尔体积的外推值与实验值分别在±0.07和±0.04 cm3/mol范围内相一致. 计算出了[Mim]Ac/[Mmim]Ac/[Emim]Ac和EtOH分别在无限稀溶液中的溶剂化系数. 用Redlich-Kister 方程关联拟合了超额摩尔体积与摩尔分数的关系. 分别根据极限偏摩尔体积、摩尔体积与极限偏摩尔体积的差值、溶剂化系数和超额摩尔体积对照讨论了分子间相互作用的强弱. 结果显示,在[Mim]Ac/[Mmim]Ac/[Emim]Ac的浓度无限稀溶液中,[Mim]Ac/[Mmim]Ac/[Emim]Ac-EtOH分子对间相互作用的强弱顺序为[Mim]Ac-EtOH>[Mmim]Ac-EtOH >[Emim]Ac-EtOH;在EtOH的浓度无限稀溶液中,以及体系中[Mim]Ac/[Mmim]Ac/[Emim]Ac的摩尔分数在0.15～0.95间时,[Mim]Ac/[Mmim]Ac/[Emim]Ac-EtOH分子对间相互作用的强弱顺序都为[Emim]Ac-EtOH>[Mmim]Ac-EtOH>[Mim]Ac-EtOH.     

293.15K时咪唑醋酸盐-乙醇二元体系的体积性质及分子间相互作用

用比重瓶法测定了293.15 K时1-甲基咪唑醋酸盐([Mim]Ac)/1,3-二甲基咪唑醋酸盐([Mmim]Ac)/1-乙基-3-甲基咪唑醋酸盐([Emim]Ac)-乙醇(EtOH)二元体系在全组成范围内的密度.计算出[Mim]Ac/[Mmim]Ac/[Emim]Ac和EtOH的表观摩尔体积和体系的超额摩尔体积.用三参数多项式关联拟合了表观摩尔体积与摩尔分数的关系,外推出组分的极限偏摩尔体积和摩尔体积.[Mim]Ac/[Mmim]Ac/[Emim]Ac和EtOH的摩尔体积的外推值与实验值分别在±0.07和±0.04 cm3/mol范围内相一致.计算出了[Mim]Ac/[Mmim]Ac/[Emim]Ac和EtOH分别在无限稀溶液中的溶剂化系数.用Redlich-Kister方程关联拟合了超额摩尔体积与摩尔分数的关系.分别根据极限偏摩尔体积、摩尔体积与极限偏摩尔体积的差值、溶剂化系数和超额摩尔体积对照讨论了分子间相互作用的强弱.结果显示,在[Mim]Ac/[Mmim]Ac/[Emim]Ac的浓度无限稀溶液中,[Mim]Ac/[Mmim]Ac/[Emim]Ac-EtOH分子对间相互作用的强弱顺序为[Mim]Ac-EtOH[Mmim]Ac-EtOH[Emim]Ac-EtOH;在EtOH的浓度无限稀溶液中,以及体系中[Mim]Ac/[Mmim]Ac/[Emim]Ac的摩尔分数在0.15~0.95间时,[Mim]Ac/[Mmim]Ac/[Emim]Ac-EtOH分子对间相互作用的强弱顺序都为[Emim]Ac-EtOH[Mmim]Ac-EtOH[Mim]Ac-EtOH.     

N-甲基哌嗪与乙酸乙酯、乙酸丁酯二元混合体系在298.15～313.15K的体积及黏度性质

测定了N-甲基哌嗪+乙酸乙酯和N-甲基哌嗪+乙酸丁酯2个二元混合体系在298.15,303.15,308.15和313.15 K的密度和黏度数据,并计算了N-甲基哌嗪+酯二元混合体系的超额摩尔体积(VEm)和黏度偏差(Δη),用Redlich-Kister多项式关联了二元体系的超额摩尔体积与组成的关系,用4个半经验公式关联黏度数据并关联了二元体系的黏滞性活化参数.结果表明,N-甲基哌嗪+乙酸乙酯和N-甲基哌嗪+乙酸丁酯二元体系在所测温度范围内的超额摩尔体积为正值,黏度偏差为负值,且二元混合体系在混合过程中焓驱动居于主导地位.     

肌醇在碱金属氯化物溶液中的体积性质

使用精密数字密度计测定了298.15和308.15 K肌醇在不同浓度的LiCl-H2O、NaCl-H2O或KCl-H2O溶液中的密度, 计算了肌醇的表观摩尔体积Vφ和极限偏摩尔体积Vθφ , 得到了其由纯水溶剂转移至混合溶剂中的迁移偏摩尔体积⊿trsVθ椎 .结果表明, LiCl, NaCl和KCl在溶液中对肌醇的体积性质影响显著, 极限偏摩尔体积Vθφ和极限迁移偏摩尔体积⊿trsVθφ都随盐浓度的增大而增加;温度对肌醇的极限偏摩尔体积和极限迁移偏摩尔体积只有轻微影响. 从分子-离子间的相互作用角度对实验结果进行了讨论.     

甘氨酸在N,N-二甲基甲酰胺水溶液中的体积性质

用Anton Paar型55精密数字密度计测定了甘氨酸在N,N-二甲基甲酰胺(DMF)水溶液中的密度,计算了甘氨酸的表观摩尔体积、极限偏摩尔体积、迁移偏摩尔体积和理论水化数,讨论了DMF的结构对甘氨酸迁移偏摩尔体积和理论水化数的影响。结果表明,甘氨酸在DMF水溶液中的迁移偏摩尔体积为正值,并且随着溶液浓度增大而增大。在DMF水溶液中的理论水化数比在纯水中的小,并且随着DMF浓度的增大而减小。把上述计算结果与在N,N-二甲基乙酰胺(DMA)水溶液中的实验结果进行了比较。     

对甲氧基苯甲醛与N,N-二甲基甲酰胺密度黏度的测定与关联

在常压,298.15K~353.15K条件下,采用U形振动管密度计测定了对甲氧基苯甲醛-N,N-二甲基甲酰胺二元物系的密度,采用乌氏黏度计测定其黏度;并由密度和黏度数据分别计算了该二元物系超额摩尔体积VE和混合黏度的变化Δη.在不同的温度和组成下超额摩尔体积和混合黏度的变化都是负值,同时对不同温度下的超额摩尔体积与组成的关系以及混合黏度的变化与组成的关系都按Redlich-Kister方程进行了拟合,计算值与实验值的最大标准偏差小于7%.     

I>D-甘露醇在正丙醇和异丙醇水溶液中的体积性质

使用石英振荡管密度计精确测定了298.15 K温度下不同浓度的甘露醇-正丙醇-水和甘露醇-异丙醇-水三元溶液的密度. 计算了甘露醇的表观摩尔体积V_Φ和极限偏摩尔体积, 得到了其由纯水溶剂转移至混合溶剂中的迁移偏摩尔体积. 结果表明, 正丙醇在溶液中对甘露醇体积性质的影响较异丙醇显著. 从溶质-溶剂分子间相互作用及丙醇同分异构体中羟基位置的不同对体积性质的变化规律进行了讨论.     

288.15, 298.15和308.15 K温度条件下甘氨酰甘氨酸在蔗糖-水混合溶剂中的体积性质研究

利用Anton Paar DMA55精密数字密度计测定了288.15, 298.15和308.15 K甘氨酰甘氨酸在蔗糖-水混合溶剂中的密度, 计算了甘氨酰甘氨酸的表观摩尔体积VΦ和极限偏摩尔体积 , 得到了其由纯水溶剂转移至混合溶剂中的迁移偏摩尔体积Δtrs 和理论水化数Nh．根据共球交盖模型, 讨论了迁移偏摩尔体积和水化数的变化规律．结果表明, 甘氨酰甘氨酸带电中心与蔗糖之间的结构相互作用对其迁移体积有正贡献, 且占主导地位．甘氨酰甘氨酸的迁移偏摩尔体积为正值, 且随着蔗糖浓度的增大而增大; 理论水化数随温度升高、蔗糖浓度的增大而减小; 温度升高, 极限偏摩尔体积增大, 迁移偏摩尔体积变化很小．     

Pb-Sn-Cd三元系Pb基α相固溶体点阵参数、摩尔体积、超额摩尔体积的研究

用X射线衍射法测定了Pb-Sn-Cd三元系Pb基α相固溶体的点阵参数和摩尔体积。发现点阵参数随摩尔分数浓度呈线性变化,点阵畸变主要受组分的尺寸效应影响;摩尔体积对理想溶液行为呈正偏差,且Cd对超额摩尔体积的贡献远大于Sn。分别按Vegard定律和亚规则溶液模型对点阵参数和摩尔体积的数据与摩尔分数的关系进行数学回归,表明两解析式的预测精度均在实验误差范围内。     

Apparent Molar Volumes and Solvation Coefficients in Ternary-pseudo-binary Mixtures [（Styrene＋Ethyl Acetate or Benzene）＋（N-Methyl-2-pyrrolidone＋Ethyl Acetate or Benzene）]

Over the full range of compositions,in the ternary-pseudo-binary mixtures of x[(1-y)C6H5CH=CH2+ yCH3COOC2H5(or C6H6)]+(1-x)[(1-y)NMP+yCH3COOC2H5(or C6H6)],the apparent molar volumes of each pseudo-pure component at different y values were calculated from the density data at 298.15 K and atmospheric pressure.The results show that the four parameters cubic polynomial can correlate the apparent molar volume with the molar fraction well over the full molar fraction range.The limiting partial molar volumes and the molar volumes of each pseudo-pure component were evaluated with different methods.Based on the limiting partial molar volume and molar volume at a certain y value,a new universal coefficient termed as solvation coefficient γ was defined to describe quantitatively the solvation degree of pseudo-pure solute and the interactions of solute-solvent molecules from the macroscopical thermodynamics viewpoint.The results demonstrate the solvation coefficients decrease with the amount of the third component increasing for each pseudo-pure solute,irrespective of the pseudo-pure solvent.Then the solvation degrees of each pseudo-pure component,the specific interactions between the solute molecule and the solvent one were discussed in terms of the solvation coefficient.     

溶剂化的热力学集团展开理论

把二元溶液的过剩内能（excess energy）分成溶剂-溶剂、溶剂-溶质及溶质-溶质相互作用部分。利用集团展开方法给出了二元溶液在正则系综的配分函数的表达式,利用该表达式得到了溶质的偏摩尔内能(partial molar energy)和偏摩尔熵(partial molar entropy)的表达式。在无限稀溶液情形,过剩偏摩尔内能的溶剂-溶剂部分又称重组织内能（reorganization energy）,它反映了溶质存在时对其周围溶剂分子之间的相互作用能的影响。研究表明,在溶质的粒子数密度相对较大时,溶质分子之间的相互作用将影响过剩偏摩尔内能的溶剂-溶剂部分,对于稀溶液,过剩偏摩尔内能的溶剂-溶剂部分与溶质的摩尔分数成线性关系。对低密度二元溶液,溶质的过剩偏摩尔内能和过剩偏摩尔熵也与溶质的摩尔分数成线性关系。     

Effect of Temperature on the Volumetric Properties of [Difurylmethane+(C<Subscript>2</Subscript>–C<Subscript>6</Subscript>) Alkan-1-ol] Binary Systems: Analyses of New and Literature Density Data in the Temperature Range 288.15–308.15 K

Densities, ρ, of the binary systems {difurylmethane + (ethanol or propan-1-ol or butan-1-ol or pentan-1-ol or hexan-1-ol)} have been measured with an Anton Paar DMA 4500 vibrating-tube densimeter over the entire composition range at 288.15 and 308.15 K and atmospheric pressure. The measured and literature densities of [difurylmethane + n-alkanol] binary systems have been used to check the validity of the relationship describing the dependence of density on composition. This relation is useful for obtaining interpolated ρ values corresponding to the experimental data. Excess molar volumes (V _m^E) of each mixture, limiting (V _m,i ^E,∞) and excess partial (V _m,i ^E) molar volumes and the limiting partial molar expansion (E _p,i ^∞) of both components of each binary system have been examined to provide insight into the temperature variations of the intermolecular interactions and molecular packing efficiencies. The results have been discussed in terms of specific intermolecular interactions and structural effects.     

Apparent Molar Volume and Apparent Molar Refraction of Mono-, Di-, Tri-, and Tetra(oxyethylene) Glycol in Aqueous, 1,4-Dioxane,and Benzene Solutions at 298.15 K

Summary. The density and refractive index of aqueous, 1,4-dioxane, and benzene solutions of poly (oxyethylene) glycols of the type HO–(CH₂CH₂O) _n –H (n varying from 1 to 4) were measured at 298.15K. From these experimental data the apparent molar volume and the apparent molar refraction at infinite dilution were calculated. The limiting apparent molar volume of the investigated compounds in a definite solvent depends linearly on the number of oxyethylene groups. From these data, the volume of the monomeric unit was evaluated and found to be greater in non-aqueous solvents than in water. The limiting apparent molar refraction of the solute for the investigated systems, within the experimental uncertainties, is equal to the molar refraction of the pure solute. The electronic polarizability of the solute molecule depends linearly on the number of monomeric units and the ratio of the electronic polarizability to the molecular van der Waals volume is constant and independent of the number of oxyethylene groups.Received February 24, 2003; accepted (revised) April 10, 2003 Published online August 18, 2003     

Excess and partial excess molar volumes of 1,4-dichlorobutane with butanols at 25 and 40°C

From density measurements over the whole composition range at 25 and 40°C excess molar volumes for binary mixtures of 1,4-dichlorobutane with l-butanol, 2-butanol, 2-methyl-l-propanol or 2-methyl-2-propanol are calculated. V^E results were fitted by the method of least squares to a smoothing equation. Excess partial molar volumes and limiting excess partial molar volumes at 25° are also calculated.     

Volumetric properties of the isopropanolamine–water mixture at atmospheric pressure from 283.15 to 353.15 K

Densities of the isopropanolamine–water binary mixture system were measured over the whole range of compositions at temperatures from 283.15 to 353.15 K using an Anton Paar digital vibrating glass tube densimeter. The density of this system has been found an increasing function of the isopropanolamine composition. Excess molar volume data, calculated from the measured experimental densities, have been correlated using the Redlich–Kister equation. Parameters for the Redlich–Kister equation have been adjusted. Partial molar volumes at infinite dilution have been calculated for each component.     

Volumetric Properties of Binary Mixtures of Isomeric Butanols and C8 Solvents at 298.15 K

Excess molar volumes, V _m ^E, over the whole composition range for binary mixtures of 1-butanol, 2-butanol, and 2-methyl-2-propanol + 1-octanol, or 2-octanol, or di-n-butyl ether, or n-hexylacetate were determined at 298.15 K from density measurements carried out with a vibrating-tube densimeter. Small V _m ^E values, both positive and negative, are displayed by mixtures containing 1- or 2-octanol, whereas positive and larger values are always found for mixtures containing dibutyl ether and hexylacetate. These results can be justified in terms of H-bonding interactions and/or steric hindrance due to the branched alkyl chains. Partial molar volumes at infinite dilution of the isomeric butanols in the C8 compounds were also calculated from the apparent molar volumes in dilute solution. The solute-solvent interactions and the effects of the local organisation of the solvent around the butanol molecules were discussed using the void and cavity volumes as different estimates of the intrinsic volume of the molecules. The volumetric behavior of butanols seems to be determined by the solute-solvent interactions rather than packaging effects.     

Partial molar volumes of tetraalkylammonium hydroxides in aqueous solution at 25°C

The densities of aqueous solutions of tetramethylammonium, tetraethylammonium, tetra-n-propylammonium and tetra-n-butylammonium hydroxide have been measured at 25°C in the concentration range 0.1–1.0 mol-kg^-1 . The apparent and partial molar volumes are calculated from the density measurements. The apparent molar volumes of the solutes show considerable deviation from the Debye-Hülckel limiting law, even at high dilution. The relation for the concentration dependence of the apparent molar volume is given in an analytical form. The limiting apparent molar volumes of the solutes are split into their ionic components by an extrathermodynamic approach and are discussed in terms of ion-solvent interactions. In this way, the limiting partial molar ionic volume for the hydroxide ion is found to be 2 cm³-mol^-1.