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Updated: Sep 15, 2025
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Determination of the Gas-phase Acidities of Oligopeptides
Published on: June 24, 2013
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Chemical and Phase Equilibrium of Formic Acid-Trialkylamine Complexes
Anouk W N de Leeuw den Bouter1,2, Esther J M Vogels1, Adeline Miquelot2
1Sustainable Process Engineering, Chemical Engineering and Chemistry, Eindhoven University of Technology, Het Kranenveld 14, 5612 AZ Eindhoven, The Netherlands.
ACS Omega
|July 14, 2025
Summary
The study shows that longer alkyl chains in trialkylamine mixtures with formic acid decrease proton transfer but increase hydrogen bonding. Phase equilibrium remains unaffected by chain length at a 1.5:1 acid-to-amine ratio.
Area of Science:
- Physical Chemistry
- Chemical Thermodynamics
- Spectroscopy
Background:
- Understanding acid-base interactions in mixtures is crucial for chemical process design.
- Formic acid-trialkylamine systems exhibit complex chemical and phase equilibria.
- The influence of cation structure on these equilibria requires detailed investigation.
Purpose of the Study:
- To investigate the effect of alkyl chain length of nitrogenous cations on ionicity and bonding in formic acid-trialkylamine mixtures.
- To analyze the interplay between chemical and phase equilibria.
- To elucidate the relationship between alkyl chain length, proton transfer, and hydrogen bonding.
Main Methods:
- Fourier Transform Infrared (FTIR) spectroscopy to analyze molecular interactions and species.
- Proton Nuclear Magnetic Resonance (1H NMR) spectroscopy for structural and bonding insights.
- Thermodynamic analysis of chemical and phase equilibria at 298.15 K.
Main Results:
- Formic acid-trialkylamine complexes exist as a mixture of ionic and neutral species.
- Phase equilibrium is independent of alkyl chain length at a 1.5:1 molar ratio (acid:amine).
- Increasing alkyl chain length decreases proton transfer but enhances hydrogen bonding characteristics.
Conclusions:
- Alkyl chain length significantly modulates the nature of interactions in formic acid-trialkylamine mixtures.
- The observed trends suggest a balance between ionicity and hydrogen bonding governed by cation structure.
- The findings provide insights into the molecular basis of phase behavior in such systems.
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