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Hydration of 3-Methyl-1,2,3-butanetricarboxylic Acid Evidenced by Matrix-Isolation Infrared Spectroscopy
Stéphane Coussan1, Christian Aupetit2, Joëlle Mascetti2
1Aix-Marseille Univ., CNRS, PIIM, Marseille 133997, France.
The Journal of Physical Chemistry. A
|January 24, 2025
Summary
3-methyl-1,2,3-butanetricarboxylic acid (MBTCA) readily forms stable aggregates with water molecules. This study reveals MBTCA
Area of Science:
- Atmospheric Chemistry
- Physical Chemistry
- Spectroscopy
Background:
- Secondary organic aerosols (SOA) form from atmospheric oxidation of volatile organic compounds.
- 3-methyl-1,2,3-butanetricarboxylic acid (MBTCA) is a key marker in SOA formation from α-pinene.
- Understanding SOA component hydration is crucial for cloud condensation nuclei (CCN) formation.
Purpose of the Study:
- Investigate the hydration mechanism of MBTCA.
- Determine the stability of MBTCA-water complexes.
- Provide experimental evidence for early hydration stages of SOA markers.
Main Methods:
- Matrix-isolation infrared spectroscopy.
- Theoretical computational chemistry calculations.
Main Results:
- Identified monomers of MBTCA and MBTCA-water heterocomplexes (MBTCA-n(H2O)).
- Confirmed the presence of intramolecularly H-bonded MBTCA monomers.
- Found MBTCA-water heterocomplexes to be more stable than MBTCA homocomplexes.
- Demonstrated MBTCA's affinity for water, facilitating H-bond network formation and solvation.
Conclusions:
- This study provides the first experimental evidence of MBTCA hydration.
- MBTCA exhibits a strong affinity for water, influencing its role in atmospheric processes.
- Understanding MBTCA hydration is fundamental to comprehending SOA aging and CCN formation.
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