利用具有光学宝石窗和电磁搅拌的高压釜测定了正了烷和异丁烷两个含水体系高温高压下的相平衡数据．温度和压力范围分别为５００Ｋ到６６０Ｋ和１０ＭＰａ到３００ＭＰａ左右．两个体系的临界曲线都是从纯水的临界点开始，首先趋向于较高压力和较低温度，经过一个温度最小值然后伸向高温高压方向．两个体系的温度极小值分别为６２４Ｋ和６２５Ｋ．还给出了相界面上的过剩体积．实验结果与其正烷烃－水体系的临界数据进行了比较． The phase equilibrium data of the two aqueous systems containing alkane and isobutane at elevated temperature and pressure were measured using an autoclave with optical gemstone windows and electromagnetic stirring. Temperature and pressure range of 500K to 660K and 10MPa to 300MPa or so. The critical curves for both systems begin at the critical point of pure water, first at higher pressure and at lower temperature, then at a minimum and then at high temperature and pressure. The minimum temperature of the two systems is 624K and 625K, respectively. The excess volume on the phase interface is also given. The experimental results are compared with the critical data of n-alkane-water system.