Abstract: An analysis of the vapor-liquid equilibrium of solvent mixture in the production of low alcohol-degree PVA showed that any two components of the solvent mixture formed an azeotrope. A separation process of extraction using water as extracting solvent was designed．The distribution coefficient of each component in the water and solvent mixture were determined．It was found that the distribution coefficient of PA was far smaller than methyl acetate and methanol，simulation results indicated that with a mass ratio of water to solvent mixture 1.75 PA in the organic phase reached a maximum．A low temperature was favorable to the extraction separation process．

摘要： 对低醇解度聚乙烯醇（PVA）制备时混合溶剂的汽液平衡进行了分析，因物系两两共沸，本研究提出采用水萃取其中相变促进剂（PA）的分离方法。实验测定了各组分在水相与混合溶剂中的分配系数，结果表明PA的分配系数远小于乙酸甲酯和甲醇，萃取剂对乙酸甲酯和甲醇的萃取能力远大于PA，证明萃取方法可行。模拟计算结果表明：萃取剂与混合溶剂质量比为1.75∶1时萃余相中PA的量达到了最大值；升高操作温度PA的萃取率降低，表明该萃取操作为放热过程，降低温度有利于萃取操作的进行。