Organic acids tunably catalyze carbonic acid decomposition

Area of Science:

• Physical Chemistry
• Computational Chemistry

Background:

• Carbonic acid decomposition is a high-energy reaction involving 1,3-hydrogen atom transfer.
• Understanding catalysis mechanisms is crucial for chemical reaction optimization.

Purpose of the Study:

• To investigate the catalytic effects of monocarboxylic and dicarboxylic acids on carbonic acid gas-phase decomposition.
• To elucidate the relationship between catalyst structure, pKa, and catalytic activity.

Main Methods:

• Density functional theory (DFT) calculations were employed to model the reaction pathways.
• Transition-state theory (TST) was used to estimate reaction rate constants.

Main Results:

• Both monocarboxylic and dicarboxylic acids catalyze carbonic acid decomposition, with carboxylic acids being more effective than water.
• Monocarboxylic acids showed higher catalytic activity than dicarboxylic acids, which are hindered by intramolecular hydrogen bonds.
• A direct correlation was found between the catalytic activity of monocarboxylic acids and their pKa values.

Conclusions:

• Carboxylic acids are effective catalysts for carbonic acid decomposition, with monocarboxylic acids being more efficient.
• Catalytic activity is influenced by pKa and the presence of intramolecular hydrogen bonds.
• The findings provide new insights into general acid catalysis mechanisms.