A systematic study on the phase behavior of saturated ethyl esters with supercritical CO₂ is presented. High pressure phase behavior measurements for the systems CO₂/ethyl decanoate, CO₂/ethyl dodecanoate, CO₂/ethyl tetradecanoate, and CO₂/ethyl hexadecanoate were conducted in a static synthetic view cell in the temperature range 308–358 K. Phase transition pressures were measured in the range 5.86–23.01 MPa for ethyl ester mass fractions in the range 0.0174–0.657 and complement existing literature data. Throughout the temperature and compositional range measured, which encompassed the liquid phase, mixture critical region, and vapor phase, an increase in temperature leads to an increase in phase transition pressure with no temperature inversions or three phase regions observed. Additionally, an increase in hydrocarbon backbone length leads to an ever-increasing phase-transition pressure, suggesting fractionation of ethyl esters according to molecular mass with supercritical CO₂ is possible. Finally, the measured and previously published CO₂/ethyl ester data were successfully correlated with a modified Chrastil models and the MT model. While these models cannot easily be used predictively and depend on the data sets used for correlation, these are simple and easy methods that can be used to interpolate data.

中文翻译：

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CO ₂ /饱和乙基酯同源系列的高压相平衡

对超临界CO ₂饱和乙酯的相行为进行了系统的研究。系统CO ₂ /癸酸乙酯，CO ₂ /十二烷酸乙酯，CO ₂ /十四烷酸乙酯和CO _2的高压相行为测量在静态合成视场中在308–358 K的温度范围内进行了十六烷酸/癸酸乙酯的测量。对于乙基酯质量分数在0.0174–0.657范围内的相变压力，测量范围为5.86–23.01 MPa，并补充了现有的文献数据。在整个测量的温度和组成范围内（包括液相，混合物临界区和气相），温度升高导致相变压力升高，而没有观察到温度反转或三相区域。另外，烃主链长度的增加导致相变压力不断增加，这表明根据分子量用超临界CO ₂进行乙酯的分馏是可能的。最后，测得的和先前发布的CO₂ /乙酯数据已成功地与修改后的Chrastil模型和MT模型相关联。虽然这些模型不能容易地预测性使用，并且依赖于用于关联的数据集，但是它们是可用于内插数据的简单方法。