本文改进了液-液平衡測定的传統实驗方法。制做了一种結构簡单,操作方便,試料用量少的小容量平衡釜。利用該方法一次測定可同时获得液-液平衡的双結点曲綫和平衡結綫数据。在相平衡组成的分析上,采用气相色譜分析代替经典的测定方法。測定了大气压下,30.0℃、40.0℃和50.0℃时甲苯-正庚烷-环丁碸的液-液平衡双結点曲綫和平衡結綫数据。分别计算了甲苯、正庚烷的分配系数和选择性系数。 This article improves the traditional liquid-liquid equilibrium determination of experimental methods. System made a simple, easy to operate, less sample volume of small capacity balance kettle. The method can be used to determine the simultaneous determination of the liquid-liquid equilibrium double junction curve and balance junction data. Analysis of the composition of the phase equilibrium, the use of gas chromatography instead of the classic method of determination. The liquid-liquid equilibrium double junction curves and equilibrium junction data of toluene-n-heptane-cyclobutane at atmospheric pressure, 30.0 ℃, 40.0 ℃ and 50.0 ℃ were measured. The partition coefficient and selectivity coefficient of toluene and n-heptane were calculated respectively.