(558au) A Rapid and Accurate QSPR Model for NH3 Solubility Prediction in Ionic Liquids

A wealth of ammonia (NH₃) is contained in various industrial emissions, such as triamine tail gas and synthetic ammonia tail gas. The direct emissions into the atmosphere not only waste resource but also result in environment problems. In recent years, ionic liquids (ILs) have attracted tremendous attention for their potential use as absorbent for NH₃ capture due to high NH₃ solubility in ILs.^1–3 However, the large number of potential ILs is a big challenge to screen optimal ILs for NH₃ absorption via experimental attempts. Therefore, the thermodynamic models, with less dependency on experimental data, for NH₃ solubility prediction in ILs are necessary and crucial.

In this work, an ionic fragment contribution-quantitative structure property relationship model, named IFC-QSPR is developed based on charge distribution area (S_{σ–profile}), total COSMO area (A_COSMO) and volume (V_COSMO) descriptors. The descriptors of ILs are predicted by our previous model, IFC–COSMO model. Then as input of QSPR model, the obtained descriptors are used to predict the NH₃ solubility in ILs. The results show that the average absolute relative deviation of the IFC–QSPR model is less than 10%. Moreover, the IFC–QSPR model is free of the dependency on professional software. Therefore, the proposed IFC–QSPR model is a rapid and accurate model to predict NH₃ solubility in ILs, which is important for industrial application of ILs for NH₃ absorption and separation.

References

[1] Zeng SJ, Liu L, Shang DW, Feng JP, Dong HF, Xu QX, Zhang XP, Zhang SJ. Efficient and reversible absorption of ammonia by cobalt ionic liquids through Lewis acid-base and cooperative hydrogen bond interactions, Green Chem. 2018; 20: 2075–2083.

[2] Shang DW, Zhang XP, Zeng SJ, Jiang K, Gao HS, Dong HF, Yang QY, Zhang SJ. Protic ionic liquid [Bim][NTf₂] with strong hydrogen bond donating ability for highly efficient ammonia absorption, Green Chem. 2017; 19: 937–945.

[3] Shang DW, Bai L, Zeng SJ, Dong HF, Gao HS, Zhang XP, Zhang SJ. Enhanced NH₃ capture by imidazolium-based protic ionic liquids with different anions and cation substituents, J. Chem. Technol. Biot. 2018; 93: 1228–1236.