Abstract: Liquid-liquid extraction(LLE) was used to analyze the contents of 1,4-butanediol(BDO) in the depolymerization solution. The LLE data for the system were measured at 30 ℃ when n-octanol was used as extracting reagent. Activity coefficient models were established to correlate the LLE data of the system using the Extended-UNIQUAC equation, in which the binary interaction energy parameters of water+BDO+n-octanol ternary system were obtained through a simplex fitting method. The results show that the composition of raffinate phase can be predicted reliably by analyzing the composition of extract phase. Therefore, the contents of BDO in the solution can be calculated. The method is accurate and simple and can be used as the common analytic method for this system.

Key words: butanediol, composition analysis, ternary liquid-liquid equilibrium, Extend-UNIQUAC model