A New Model for Estimation of Activity Coefficient of Water atInfinite Dilution in Ionic Liquids

Estimation of activity coefficient of water at infinite dilution in ionic liquids (ILs) is very importantfor natural gas dehydration design and application. For this purpose, in this work a new simplequantitative structure-property relationship (QSPR) model with only three parameters was successfullydeveloped to predict this property. To better distinct the effects of anion and cation on the activitycoefficient of water in ILs, more than ۱۰۰۰ molecular descriptors were calculated for each of cationand anion of an IL. An efficient approach combining modified particle swarm optimization (MPSO) andmultiple linear regression (MLR) was used for selecting the most important molecular descriptors andbuilding the optimal QSPR model. The number of molecular descriptors in final QSPR model was ۲ foranions and ۱ for cations. The proposed QSPR model resulted in squared correlation coefficient valuesof ۰.۹۵۹ and ۰.۹۶۵ for the training and test sets, respectively. The obtained results in this paper suggestthat by the proposed model, it is possible to obtain a good estimation of activity coefficient of water atinfinite dilution in ILs.

Keywords:

Activity coefficient , Dehydration , Infinite dilution , Ionic liquids , Quantitative structurepropertyrelationship (QSPR) , Natural gas