预测乙烷/离子液体系统溶解平衡的UNIFAC模型

UNIFAC Model for Prediction of Dissolution Equilibrium of Ethane/Ionic Liquid Systems

采用UNIFAC模型对乙烷在1-烷基-3-甲基咪唑双三氟甲基磺酰亚胺盐([RMIm][Tf2N],R=乙基(E)、丁基、己基、辛基(O)、癸基)离子液体中的113个溶解度数据进行关联,得到了乙烷与主基团CH2—和[MIm][Tf2N]间的交互参数,建立了预测乙烷在该类离子液体中溶解度的UNIFAC模型。利用该模型预测了乙烷在[EMIm][Tf2N]和[OMIm][Tf2N]两种离子液体中的溶解度,预测值与文献值吻合较好,平均误差分别为4.01%和3.81%,最大误差为9.86%。将该模型用于分析改变烷基链长对乙烷在[RMIm][Tf2N]离子液体中溶解度的影响发现,在烷基链长较短时,增加其链长可有效提高乙烷的溶解度;但当烷基链长较长时,其效果减弱。该模型可对乙烷在该类离子液体中的溶解度进行有效预测,为其相关的传质分离过程提供相平衡数据。

113 Solubility data of ethane in ionic liquids 1-alkyl-3-methylimidazolium bis（trifluoromethylsulfonyl）imide（ERMIm] [Tf2N], R=ethyl（E）, butyl, hexyl, octyl（O）, decyl） were fitted by the UNIFAC model and the interaction parameters between C2H6, and CH2- and [MIm] [Tf2N] were obtained. The UNIFAC model was used to predict the solubilities of ethane in [EMIm] [Tf2N] and [OMIm] [Tf2N]. The results showed that the predicated data agreed with the experimental data well, the average relative deviations were 4.01% and 3.81% respectively, and the largest relative deviation was 9.86%. The effect of alkyl chain length on the ethane solubility in the ionic liquids was investigated by means of the UNIFAC model. It was found that increasing the alkyl chain length could enhance the dissolution effectively when the length was relatively short, but when the carbon number was larger than 10, the effects became weaker. The obtained UNIFAC model is useful for predicting the ethane solubility in [ RMIm ] [Tf2N ].