Due to the electropositivity of the carbon atom in CO₂ which results from its lower electron density compared to that of the oxygen atom, CO₂ molecules can act either as proton acceptor or electron acceptor. The specific intermolecular interaction (i.e., Lewis acid-base interaction) between CO₂ and organic chemicals with electron donor groups exists, and this phenomenon is supported by many experimental studies using spectrometry and ab initio studies. CO₂/alcohol solvent systems under high-pressure conditions are important for supercritical extraction, dehydration of alcohols, and extraction of natural products. Furthermore, the study of the complex between CO₂ and alcohols due to the Lewis acid-base interaction is crucial for understanding the solvation process under high-pressure conditions, and for the development of thermodynamic models. In this study, the Lewis acid-base interaction between alcohols and CO₂ is treated as a hydrogen bonding interaction, and according to the different association schemes for CO₂, the effect on the phase behavior of the CO₂/alcohol systems at high pressure was investigated using the Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT) model. Taking into consideration the self-association of CO₂ yields a more satisfactory performance in the high-pressure region than it would without, and increasing association sites of CO₂ do not lead to a better performance. In addition, the cross-association energy (i.e., Lewis acid-base interaction energy) parameter is estimated by directly regressing the experimental data over the entire temperature and pressure range, and the calculated results show an improved performance even at much higher pressures. It was found that strong cross-association interactions lead to higher cross-association in both liquid and vapor phases, which contributes to the improved phase behavior at high-pressures.

由于与氧原子相比，CO ₂中的碳原子的电子密度较低，因此碳原子具有正电性，因此CO ₂分子可以充当质子受体或电子受体。CO ₂和具有电子给体基团的有机化学品之间存在特定的分子间相互作用（即路易斯酸碱相互作用），这种现象得到了许多使用光谱法和从头研究的实验研究的支持。高压条件下的CO ₂ /醇溶剂系统对于超临界萃取、醇脱水和天然产物的萃取非常重要。此外，研究 CO ₂由于路易斯酸碱相互作用而产生的醇和醇对于理解高压条件下的溶剂化过程以及热力学模型的开发至关重要。本研究将醇与CO ₂之间的路易斯酸碱相互作用视为氢键相互作用，根据CO ₂的不同缔合方案，对高压下CO ₂ /醇体系相行为的影响使用扰动链统计关联流体理论（PC-SAFT）模型进行了研究。考虑到 CO ₂的自缔合在高压区产生比没有时更令人满意的性能，并且增加了 CO _{2 的}缔合位点不会导致更好的性能。此外，交叉缔合能（即路易斯酸碱相互作用能）参数是通过在整个温度和压力范围内直接回归实验数据来估计的，计算结果显示即使在更高的压力下性能也有所提高。发现强交叉缔合相互作用导致液相和汽相中更高的交叉缔合，这有助于改善高压下的相行为。