Abstract A volumetric equation of state (PVT behavior of a fluid) is often based on a critical isotherm. Soave-Redlich-Kwong and Peng-Robinson are by far the most popular cubic equations of state. These equations use the first and second differential conditions at the critical point to obtain the parameters but fail to reproduce the P-V-T behavior near the critical point. A new simple equation is proposed for the critical isotherm which matches experimental data for a variety of molecules in the entire range from critical point to ideal gas condition as well as the liquid region. The new proposed critical isotherm equation matches experimental data of a wide variety of compounds much better than these cubic equations of state employed commonly.

中文翻译：

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纯化合物临界等温线的简单关联

摘要 体积状态方程（流体的 PVT 行为）通常基于临界等温线。Soave-Redlich-Kwong 和 Peng-Robinson 是迄今为止最流行的三次状态方程。这些方程使用临界点处的一阶和二阶微分条件来获得参数，但未能重现临界点附近的 PVT 行为。为临界等温线提出了一个新的简单方程，该方程与从临界点到理想气体条件以及液体区域的整个范围内的各种分子的实验数据相匹配。新提出的临界等温线方程与各种化合物的实验数据相匹配，比通常使用的这些三次状态方程要好得多。