甲苯-正己烯-二甲基亚砜液-液平衡数据的测定与关联

Determination and correlation of liquid-liquid equilibrium data for toluene-n-hexene-dimethyl sulfoxide system

裂解汽油是含有烯烃的重要芳烃资源,二甲基亚砜(DMSO)能够从高烯烃含量组分中选择性萃取芳烃,测定相应体系液-液平衡是裂解汽油中的芳烃萃取过程研究开发的理论基础。测定了常压下293.15、298.15、303.15K时甲苯-正己烯-DMSO体系液-液平衡数据,获得了三元体系的相图和褶点,并采用Hand方程和NRTL方程进行关联。体系中甲苯对正己烯选择性系数为2～6,表明DMSO萃取分离甲苯和正己烯理论上可行。通过体系液-液平衡关联获得了NRTL方程模型参数,利用NRTL模型对该体系进行计算,计算值与实验值的平均偏差较小,说明NRTL模型适用于该体系的液-液平衡。

Pyrolysis gasoline is an important resource of aromatics with high content of olefins, and dimethyl sulfoxide （DMSO） is a solvent that could extract aromatics from olefins selectively. Liquid-liquid equilibrium （LLE） of toluene-n-hexene-DMSO system is the basis for the extraction of aromatics from pyrolysis gasoline. In this study, LLE data of toluene-n-hexene-DMSO system at 293.15 K, 298.15 K and 303.15 K were determined at atmospheric pressure, the phase diagram and plait point of this ternary system were obtained. The equilibrium data were well correlated by Hand and NRTL model. The parameters in the NRTL model for the ternary system and a formula of equilibrium data for industrial extraction were obtained. The LLE data predicted with the NRTL model are in satisfactory agreement with experimental data. The selectivity coefficients indicate that it is possible to separate toluene and n-hexene using DMSO.