气提法测定醇烃体系的无限稀释活度系数

The Measurement of Infinite Dilution Activity Coefficients of Alcohol-n-Alkane Systems by Gas Stripping Method

气提法测定了四个醇烃体系:甲醇—正己烷,甲醇—正庚烷,乙醇—正己烷,乙醇—正庚烷在25～45℃温度区域内的无限稀释活度系数。用1nγ~∞=A+B/T(K)关联,线性良好。 本工作使用了新设计的气提平衡釜,在釜内新增加一个导液管,使得因搅拌而循环下行的液体与上行的气泡充分接触,以达到最佳的气提平衡效果。 以γ~∞实验值用三个局部组成模型,Wilson方程,NRTL方程和UNIQU AC方程就互溶的乙醇—烷烃体系进行全浓度范围汽液平衡推算,与文献中实验值相比,发现UNIQU AC方程结果最好。

Infinite dilution activity coefficients of four alcohol-n-alkane aystems: methanol-n-hexane, methanol-n-heptane, ethanol-n-hexane, ethanol-n-he-ptane have been measured by gas stripping method in the 25-45℃ temperature region. Good linear dependencies of the ln λ∞ with 1/T have been found for all four systems within the limit of the experimental errors,A new equilibrium cell is designed. The major improvement compared with those shown in literatures is that a liquid-conducted-tu.be has been added. The Saturations become more efficient for the stripping bubbles which are moving up a gainst the circulating solution when it is being stirred.λ∞'s are used to predict the whole range VLE for the miscible ethanol-alk ane systems using three local composition models; Wilson eguation, NRTL equation and UNIQUAC equation. The predicted results are compared with the experimental data presented in literatures. The UNIQUAC equation gives the best results.