Abstract: The phase equilibrium of the nicotine system holds great significance in guiding the separation and purification of nicotine, as well as exploring the release laws of nicotine and active ingredients in heated cigarettes. The conductor-like screening model-segment activity coefficient (COSMO-SAC) enables the prediction of phase equilibria and other properties through quantum chemical calculations. In this study, the vapor-liquid phase equilibria of nicotine with binary systems consisting of mono-alcohols (methanol, ethanol, n-propanol, isopropanol, butanol, pentanol, hexanol, heptanol, octanol) and poly-alcohols (ethylene glycol, 1,2-propanediol, 1,3-propanediol, and glycerol) are predicted respectively using the COSMO-SAC model. The results show that alcohol molecules exhibit peaks in both the donor and acceptor regions of hydrogen bonds, whereas nicotine only exhibits a peak in the acceptor region. This suggests that nicotine can only act as a hydrogen bond acceptor to receive protons and form hydrogen bonds. The nicotine-alcohol binary systems are all positive deviation systems; specifically, the binary systems of mono-alcohols and nicotine exhibit general positive deviation systems and show a similar phase diagram profile, however, as the number of carbon chains of alcohols increases, the area of the gas-liquid coexistence region becomes smaller; the binary systems of poly-alcohols and nicotine exhibit the azeotropic phenomenon, which is a system with minimum azeotrope. As the temperature rises, the pressure and composition of the azeotrope increase accordingly. At 101.3 kPa, the temperature and composition of the azeotrope are 511.4 K and 0.261 for glycerol/nicotine, 459.5 K and 0.857 for 1,2-propanediol/nicotine, 483.0 K and 0.727 for 1,3-propanediol/nicotine, and 467.0 K and 0.889 for ethylene glycol/nicotine. These research results provide theoretical data to guide the purification and separation of nicotine and to understand the release law of nicotine.

Key words: Nicotine, Alcohol, COSMO-SAC, Vapor-liquid phase equilibrium, Prediction

摘要： 类导体屏蔽片段活度系数模型(COSMO-SAC)可直接通过量子化学计算实现相平衡等性质的预测。本工作结合COSMO-SAC模型预测了烟碱分别与一元醇(甲醇、乙醇、丙醇、异丙醇、丁醇、戊醇、己醇、庚醇、辛醇)和多元醇(乙二醇、1,2-丙二醇、1,3-丙二醇、丙三醇)组成的二元体系的汽-液相平衡。结果表明，醇与烟碱的二元体系均为正偏差体系；其中，一元醇与烟碱的二元体系均为一般正偏差体系，相图轮廓类似，但随着醇类物质碳链数目增加，汽-液共存区的面积减小；烟碱与多元醇构成的二元体系均会出现恒沸现象，是一个具有最低恒沸点的系统。温度越高，恒沸混合物形成的压力和比例也越高。在101.3 kPa下，丙三醇/烟碱体系的恒沸温度和恒沸组成分别为511.4 K和0.261，1,2-丙二醇/烟碱的为459.5 K和0.857，1,3-丙二醇/烟碱的为483.0 K和0.727，乙二醇/烟碱的为467.0 K和0.889。研究结果为指导烟碱的纯化分离以及认识烟碱的释放规律提供了理论数据。

关键词: 烟碱, 醇, COSMO-SAC, 汽-液相平衡, 预测