Abstract:

The solid-liquid equilibrium data for a ternary system of 4-hydroxybenzaldehyde (3) + 3-bromo-4-hydroxybenzaldehyde (2) + 3,5-dibromo-4-hydroxybenzaldehyde (1) were determined with differential scanning calorimetry (DSC).The data were obtained through the method of determining the solid-liquid equilibrium data for the pseudo-binary solution.The solid-liquid equilibrium data of the ternary system showed that the mixture was a eutectic system with mole fractions x_l=0.2445, x₂=0.3883, x₃ =0.3672, and T_eu=338.5 K.The corresponding eutectic type phase diagram was also presented.The data were correlated by the Ott’s equation.With interaction parameters from binary systems，the Wilson equation was extended to correlate the solid-liquid equilibrium data of the ternary system and the root mean square deviation of temperature was only 0.97 K.It demonstrates that the Wilson equation predicts the solid-liquid equilibrium for the ternary system with fair accuracy.

Key words:

固液平衡, 4-羟基苯甲醛, 3-溴-4-羟基苯甲醛, 3,5-二溴-4-羟基苯甲醛, 差示扫描量热法, 相图

摘要： 采用差热扫描量热法，通过对一系列“拟二元”物系固液平衡的测定，得到了4-羟基苯甲醛、3-溴-4-羟基苯甲醛和3,5-二溴-4-羟基苯甲醛物系的三元固液平衡数据，实验结果表明本物系为简单低共熔型，其低共熔摩尔组成和温度分别为：3,5-二溴-4-羟基苯甲醛（x₁）＋3-溴-4-羟基苯甲醛（x₂）＋4-羟基苯甲醛（x₃），x₁=0.2445，x₂=0.3883，x₃=0.3672，T_eu＝338.5 K。同时绘制出相应三元相图，并采用Ott方程对实验数据进行了很好的关联；根据Wilson方程由二元溶液的相互作用参数，对本物系进行计算，关于温度的标准偏差为0.97 K，计算值和实验值符合良好，说明Wilson方程能较好地描述文中三元固液平衡体系。

关键词:

固液平衡, 4-羟基苯甲醛, 3-溴-4-羟基苯甲醛, 3,5-二溴-4-羟基苯甲醛, 差示扫描量热法, 相图