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.
利用Anton Paar DMA4500振动管密度计测量了293．15K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±0．005kg／m^3。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．
