This work reports saturated-phase densities for the CO₂ + methylcyclohexane system at temperatures between 298 and 448 K and at pressures up to the critical pressure. The densities were measured with a standard uncertainty of <1.5 kg·m^–3 and were fitted along isotherms with a recently developed nonlinear empirical correlation with an absolute average deviation (Δ_AAD) of about 1.5 kg·m^–3. This empirical correlation also allowed the estimation of the critical pressure and density at each temperature, and the obtained critical pressures were found to be in close agreement with previously published data. We also compare both our density data and vapor–liquid equilibrium (VLE) data from the literature with the predictions from two models: PPR-78 and SAFT-γ Mie. The results show that densities were predicted better with SAFT-γ Mie than with PPR-78, whereas PPR-78 generally performed better for VLE. This could indicate that some of the unlike parameters of SAFT-γ Mie could be further optimized.

中文翻译：

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(CO2 + 甲基环己烷) 在温度 298 至 448 K 和压力高达临界压力下的饱和相密度

_{这项工作报告了 CO 2} + 甲基环己烷系统在 298 和 448 K 之间的温度和高达临界压力的压力下的饱和相密度。密度是用 <1.5 kg·m ^–3的标准不确定度测量的，并沿等温线拟合最近开发的非线性经验相关性，绝​​对平均偏差 (Δ _AAD ) 约为 1.5 kg·m ^–3. 这种经验相关性还允许估计每个温度下的临界压力和密度，并且发现获得的临界压力与先前公布的数据非常一致。我们还将文献中的密度数据和汽液平衡 (VLE) 数据与两个模型的预测进行了比较：PPR-78 和 SAFT-γ Mie。结果表明，SAFT-γ Mie 的密度预测优于 PPR-78，而 PPR-78 通常对 VLE 表现更好。这可能表明 SAFT-γ Mie 的一些不同参数可以进一步优化。