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Modeling temperature dependency of amine basicity using PCM and SM8T implicit solvation models
Mayuri Gupta1, Eirik F da Silva, Hallvard F Svendsen
1Department of Chemical Engineering, Norwegian University of Science and Technology, Trondheim, Norway.
The Journal of Physical Chemistry. B
|January 19, 2012
Summary
Continuum solvation models accurately predict the temperature trends of amine acidity constants (pKa) for CO(2) capture. A correction term improves absolute pKa predictions, aiding solvent selection for postcombustion carbon capture.
Area of Science:
- Computational Chemistry
- Physical Chemistry
- Chemical Engineering
Background:
- Amine-based solvents are crucial for postcombustion CO(2) capture.
- Understanding the temperature-dependent acidity of amines (pKa) is vital for optimizing solvent performance.
- Accurate computational prediction of pKa trends is needed to guide solvent selection.
Purpose of the Study:
- To investigate the temperature dependency of pKa for amines relevant to CO(2) capture.
- To evaluate the performance of PCM and SM8T continuum solvation models in predicting these trends.
- To assess the applicability of computational methods for selecting optimal CO(2) capture solvents.
Main Methods:
- Density Functional Theory (DFT) calculations were employed.
- Gaseous phase calculations utilized B3LYP and M06 functionals with the 6-311++G(d,p) basis set.
- PCM and SM8T continuum solvation models were used to simulate aqueous environments.
Main Results:
- Continuum solvation models successfully predicted the temperature trends of amine pKa values.
- A correction term was introduced to improve the accuracy of absolute pKa predictions.
- The study analyzed 10 amines with available experimental temperature-dependent pKa data.
Conclusions:
- The studied solvation models provide a reliable basis for understanding amine pKa temperature dependencies.
- Computational pKa predictions, with corrections, can aid in selecting effective solvents for postcombustion CO(2) capture.
- Temperature-dependent pKa data is essential for optimizing amine solvent selection for CO(2) capture processes.
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