Mixtures containing isobutane, carbon dioxide, and/or hydrogen are found in various industrial processes, green refrigerant systems, and the growing hydrogen industry. Understanding the thermophysical properties of these mixtures is essential for these processes, and depends on reliable experimental data. Making use of an automated static-analytical apparatus, measurements were made of the phase behavior of binary mixtures of isobutane with CO₂ and with H₂, extending the range of available data for both mixtures. Measurements of the system isobutane + CO₂ were carried out along three isotherms at temperatures of (240, 280, and 310) K with pressures from the lower limit of the sampling system (~ 0.5 MPa) to the mixture critical pressure. The results exhibit good agreement with literature data. Measurements on isobutane + H₂ were carried out along nine isotherms at temperatures of (190, 240, 280, 311, 339, 363, 375, 390, and 400) K with pressures up to 20 MPa, covering a much broader range of conditions than the one prior investigation. The results have been used to optimize temperature-dependent binary parameters in the Peng–Robinson equation of state with two different mixing rules. This approach was found to perform well in comparison to alternative models.

含有异丁烷、二氧化碳和/或氢气的混合物存在于各种工业过程、绿色制冷剂系统和不断发展的氢气工业中。了解这些混合物的热物理性质对于这些过程至关重要，并且依赖于可靠的实验数据。利用自动静态分析装置，测量了异丁烷与CO ₂和H ₂的二元混合物的相行为，扩展了两种混合物的可用数据范围。系统异丁烷+CO ₂的测量沿着三个等温线进行，温度为(240、280和310)K，压力从采样系统的下限(~0.5MPa)到混合物临界压力。结果与文献数据吻合良好。异丁烷 + H ₂的测量沿着九个等温线进行，温度为（190、240、280、311、339、363、375、390 和 400）K，压力高达 20 MPa，涵盖了更广泛的条件范围比之前的一项调查。结果已用于优化具有两种不同混合规则的 Peng-Robinson 状态方程中与温度相关的二元参数。与替代模型相比，这种方法表现良好。