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Determinant Factor for Thermodynamic Stability of Sulfuric Acid-Amine Complexes
Jia Han1, Lei Wang1, Hanhui Zhang1
1Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China.
The Journal of Physical Chemistry. A
|November 26, 2020
Summary
Atmospheric amines influence aerosol particle nucleation. Electrostatic potential, not just base strength, determines sulfuric acid-amine complex stability, offering new ways to assess amine nucleation abilities.
Area of Science:
- Atmospheric Chemistry
- Chemical Physics
Background:
- Atmospheric amines are crucial for sulfuric acid-mediated aerosol particle nucleation.
- Previous studies linked amine enhancing effects to base strength, but exceptions exist.
Purpose of the Study:
- Investigate the thermodynamic stability of sulfuric acid-alkylamine complexes.
- Clarify the role of amine properties in aerosol nucleation.
Main Methods:
- Theoretical investigation of seven alkylamines (ethylamine, propylamine, isopropylamine, tert-butylamine, dimethylamine, ethylmethylamine, trimethylamine).
- Analysis of molecular structures, electrostatic potential distribution, and van der Waals interactions.
Main Results:
- A dual hydrogen bond configuration is typical for stable primary and secondary amine complexes.
- Electrostatic potential distribution accurately predicts stabilization, aligning with base strength.
- Van der Waals interactions contribute to the stability of dimethylamine and ethylmethylamine complexes.
Conclusions:
- Amine electrostatic potential distribution is the key factor in thermodynamic stability.
- This finding provides a new method for evaluating amine nucleation-enhancing abilities in atmospheric aerosols.
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