二元体系C6H5CH3-DMF在293.15 K时的体积性质

利用Anton Paar DMA4500振动管密度计测量了293.15 K时二元体系甲苯-N,N-二甲基甲酰胺(C6H5CH3-DMF)在C6H5CH3(摩尔分数0~1)中的溶液密度, 利用最小二乘法关联了溶液密度与组成的函数关系, 关联精度为±0.005 kg/m3. 通过密度数据分别计算了二元体系中C6H5CH3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C6H5CH3和DMF的表观摩尔体积和摩尔分数的函数关系, 以及C6H5CH3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C6H5CH3和DMF的极限偏摩尔体积、标准偏摩尔体积和摩尔体积. 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方程关联拟合得到方程系数. 计算关联了C6H5CH3和DMF的超额偏摩尔体积与摩尔分数的关系. 由三参数多项式极限法得到组分的极限超额偏摩尔体积值与Redlich-Kister系数法得到的值在误差范围内一致.     

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.     

在278.15-318.15 K范围内DMF-H2O体系的超额摩尔体积及DMF的表观摩尔体积和偏摩尔体积的测定与研究

本文应用振动管式密度计, 测定了278.15—318.15 K范围内10个温度下, DMF-H_2溶液的密度随组成的变化. 根据密度值求出溶液的超额体积VE; 在全部浓度的范围内不同组成下DMF的表观摩尔体积φv及偏摩尔体积V_(DMF); 及VE、φv和V_(DMF)随组成变化的规律. 发现V_(DMF)随x_(DMF)的变化与NaCl由水至DMF-H_2O溶液的转移熵有对应的变化规律, 均在x_(DMF)≈0.075处有极值, 从而进一步对DMF-H_2O的液体结构进行了讨论, 认为当x_(DMF)=0.075时, 单个DMF分子可能嵌入12个水分子组成的分子笼中, 从而形成最紧密结构。     

正构烷烃/JP-10二元体系的体积性质

利用Anton PaarDMA55和Ubbelohde黏度管分别测定了正辛烷和正癸烷两种正构烷烃与挂式四氢双环戊二烯{C10H16, exo-tricycle[5.2.1.02.6]decane(JP-10)}组成的二元体系在298.15 K下的密度和黏度, 计算了正构烷烃/JP-10二元体系的超额摩尔体积、组分的表观摩尔体积和偏摩尔体积等体积性质以及组分对超额体积的贡献, 研究结果表明, 烷烃的加入使得二元体系的超额体积均为负值. 根据Eyring液体黏性流动理论, 关联了二元体系的黏滞性活化参数, 结果表明, 熵驱动起主要作用. 从分子间相互作用角度讨论了二元体系体积性质的变化规律.     

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%.     

正丁醇/正戊醇+JP-10二元体系的体积性质

在常压下测定了298.15 K时正丁醇/正戊醇+挂式四氢双环戊二烯(C₁₀H₁₆, JP-10)二元体系的黏度和密度. 根据Eyring液体黏性流动理论, 关联了二元体系的黏滞性活化参数, 结果表明, 焓驱动起主要作用. 利用密度数据计算了醇+JP-10二元体系的超额摩尔体积、 超额偏摩尔体积、 表观摩尔体积及偏摩尔体积等体积性质, 结果表明此二元体系的超额摩尔体积为正值.     

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.     

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。     

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.     

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.     

Volumetric Properties of Difurylmethane in Methanol from 288.15 to 308.15 K

The densities of binary systems of difurylmethane (DFM) in methanol have been measured with an Anton Parr DMA 4500 vibrating-tube densimeter over the entire composition range at intervals of 5 K in the temperature range between 288.15 and 308.15 K. Excess molar volumes of the mixture, apparent molar volumes of DFM, and excess partial molar volumes of both components have been calculated to provide insight into the intermolecular interaction present in the mixtures investigated. Excess molar volumes have been fitted to a Redlich–Kister equation and they exhibited negative deviations from ideal behavior. Both the apparent molar volume of DFM and excess partial molar volumes of DFM and methanol exhibit a dependence on composition but are less sensitive to temperature.     

Partial molar volumes of 18-crown-6 ether in organic solvents at 25°C

The partial molar volumes at infinite dilution of 18-crown-6 ether (CE) in a variety of polar and polarizable solvents with molar volumes ranging from 18 to 170 cm³-mol^–1, were measured at concentrations ranging from 0.02 to 0.1 mol-L^–1 at 25°C. The partial molar volumes of the solute at infinite dilution showed remarkable dependancy on the molar volume of the solvent. The partial molar volumes at infinite dilution for the CE increases as the solvent molar volume increases.     

正己烷在乙醇,乙醇—水混合物中的偏摩尔体积

汽油与醇混合物作为动力燃料已日益广泛。为了研究醇中杂质水对这种新型动力燃料有关热力学性质的影响,Letcher等测定了正庚烷-水-醇类三元体系的液-液平衡状态。本文报道C_6H_(14)-C_2H_5OH和C_6H_(14)-C_2H_5OH-H_2O混合物在303.15K的密度,并由此算得正已烷的表观摩尔体积和偏摩尔体积。     

High-Pressure Densities and Derived Volumetric Properties (Excess,Apparent and Partial Molar Volumes) of Binary Mixtures of Methanol + [BMIM][PF<Subscript>6</Subscript>]

The density of five (0.02297, 0.08317, 0.26147, 0.49343, 0.75255 mole fraction BMIMPF₆) binary methanol + BMIMPF₆ (1-n-butyl-3-methylimidazolium hexafluorophospate) mixtures have been measured with a vibrating-tube densimeter. Measurements were performed at temperatures from 298 to 398 K and at pressures up to 40 MPa. The total uncertainties of the density, temperature, pressure, and concentration (mole fractions) measurements were estimated to be less than 0.1 kg⋅m⁻³, 15 mK, 5 kPa, and 10⁻⁴, respectively. The uncertainties reported in this paper are expanded uncertainties at the 95% confidence level with a coverage factor of k=2. The measured densities were used to study of the effect of temperature, pressure, and concentration on the derived volumetric properties such as excess, apparent and partial molar volumes. It is shown that the values of excess molar volume for methanol + BMIMPF₆ mixtures are negative at all measured temperatures and pressures in the whole concentration range. The measured densities were used to develop Tait-type equations of state for pure components and the mixtures. The structural properties such as direct and total correlation function integrals were calculated using the derived partial molar volumes at infinite dilution.     

Studies on Lattice Parameter,Molar Volume and Excess Molar Volume of Pb-based a-phase Solid Solution in Pb-Sn-Cd Ternary System

The lattice parameters a and the molar volumes Km of Pb-based a-phase solid solutions in the Pb-Sn-Cd ternary system were determined by means of X-ray diffraction. The lattice parameters a vary linearly with the molar fractions, the molar volumes show a positive deviation from the ideal solution behaviour, and the contribution of the solute Cd to the excess molar volumes V is much larger than that of the solute Sn. According to Vegard' s law orsub-regular solution model, the relationship between the experimental data of a or Vm andthe compositions of alloy is obtained by the mathematic regressive method, the prediction precisions of the both formulae are within the limits of experiment error.