COSMOSPACE is an activity coefficient model in which the activity coefficient of the components in a liquid chemical mixture can be related through their molar fraction.
While UNIQUAC is a first order approximation, COSMOSPACE gives the exact solution of a lattice model in which pairwise molecule surfaces interact. Therefore, COSMOSPACE outperforms Uniquac in the description of vapor–liquid and liquid–liquid phase equilibria.
References
COSMOSPACE Wikipedia(Text) CC BY-SA