The product of 1-butyl-3-methylimidazolium acetate [Ionic liquid] when it reacts with CO2 is an adduct. I am trying to model this system in Aspen plus using E-NRTL. The problem arises when I want to regress pair parameters of the product of 1-butyl-3-methylimidazolium acetate for E-NRTL as the adduct does not show up in Molecule j or Electrolyte j in Aspen plus.

Any Idea on how to tackle such problem?