Reparametrization of COSMO-RS for (polymer) ionic liquids

COSMO-based model for gas solubility in polymer ionic liquids (2021 paper)

Gas solubility in polymers plays an important role in processing advanced polymer materials. An important and relatively unexplored class of polymers is polymer ionic liquids (PILs).

In a 2021 paper, different COSMO-RS parameterizations were used in combination with polymer functionality in AMS-COSMO-RS to predict gas solubility in standard polymers and PILs. For regular polymers, the standard COSMO-RS parametrization performs best, while for CO₂ solubility in PILs, the ionic liquid parametrization (ADF-Lei 2018, see below) had the most accurate predictions.

COSMO-RS (ADF 2018 Lei) predictions for the CO₂ gas solubility in PILs (P([VBMTA][BF₄]).

New and improved COSMO-RS parameters for CO2 solubility in ionic liquids (2018 paper)

In a recent Green Energy & Environment publication Lei and coworkers present a reparametrization of COSMO-RS parameters for ionic liquids within the ADF framework. The extensive training set consisted of 2283 activity coefficient data points at infinite dilution and 1433 CO₂ solubility data points that were collected from literature references.

The authors use the refitted parameters to predict CO₂ solubility in pure ionic liquids at low temperatures (<273.2 K) and the CO₂ solubility in mixed ionic liquids over a wide temperature and pressure range.

Try the parameters with AMS COSMO-RS

The refitted optimal values for the misfit energy constant a’, hydrogen bond coefficient c_hb and the effective contact surface area of a segment a_eff can be selected in the AMS COSMO-RS GUI (Method -> Parameters; For the Use drop-down select: ADF Lei 2018). You can now try these parameters in the ionic liquids COSMO-RS tutorial. In previous AMS releases you could change the parameters by hand:

a' = 2063.0 (kcal/mol) A^2/e^2
c_hb = 7532.0 (kcal/mol) A^2/e^2
a_eff = 3.34 A^2

Ruisong Zhu, Zhigang Lei, COSMO-based models for predicting the gas solubility in polymers, Green Energy & Environment (2021)

Jingli Han, Chengna Dai, Gangqiang Yu and Zhigang Lei, Parameterization of COSMO-RS model for ionic liquids, Green Energy & Environment (2018).