The Influence of Pressure on the Carbon Dioxide Absorption in Ionic Liquids
- 1Mulliken Center for Theoretical Chemistry, Clausius Institute for Physical and Theoretical Chemistry, University of Bonn, Beringstraße 4, Bonn, Germany, 53111
Abstract
In this work, we systematically investigate the pressuredependent CO2 absorption behavior in ionic liquids and a switchable solvent using density functional theory calculations under hydrostatic pressure, combined with ab initio molecular dynamics simulations. A diverse set of ionic liquid anions was examined to identify structural motifs that govern the absorption behavior. Pressure was found to significantly affect reactivity, allowing access to chemically bound anion–CO2 complexes that are not observed under ambient conditions. We identified fully reversible, irreversible, and purely physical CO2 absorption with the application of external pressure. Nitrogen-rich heterocyclic anions were shown to predominantly exhibit irreversible CO2 absorption, whereas oxygen-based anions with moderate nucleophilicity mostly show reversible pressure-switchable behavior. Ab initio molecular dynamics simulations of a representative ionic liquid system confirmed pressureactivated CO2 absorption at the dynamic condensed-phase level. The pressure-induced CO2 absorption mechanism was further validated using the switchable solvent N,Ndimethylethanolamine, which is known to bind CO2 reversibly with the application of pressure. These results provide molecular-level insights into pressure-induced CO2 absorption and establish design principles for tailoring ionic liquids specifically for tunable, energy-efficient CO2 capture applications.
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BibTeX
@misc{muller2026influence,
title = {{The Influence of Pressure on the Carbon Dioxide Absorption in Ionic Liquids}},
author = {Anna K. Müller and Johannes Ingenmey and Barbara Kirchner},
howpublished = {ChemRxiv},
year = {2026},
month = sep,
doi = {10.26434/chemrxiv.15008425/v1},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008425/v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - The Influence of Pressure on the Carbon Dioxide Absorption in Ionic Liquids
AU - Anna K. Müller
AU - Johannes Ingenmey
AU - Barbara Kirchner
PY - 2026
DA - 2026/09/07
PB - ChemRxiv
DO - 10.26434/chemrxiv.15008425/v1
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008425/v1
AB - In this work, we systematically investigate the pressuredependent CO2 absorption behavior in ionic liquids and a switchable solvent using density functional theory calculations under hydrostatic pressure, combined with ab initio molecular dynamics simulations. A diverse set of ionic liquid anions was examined to identify structural motifs that govern the absorption behavior. Pressure was found to significantly affect reactivity, allowing access to chemically bound anion–CO2 complexes that are not observed under ambient conditions. We identified fully reversible, irreversible, and purely physical CO2 absorption with the application of external pressure. Nitrogen-rich heterocyclic anions were shown to predominantly exhibit irreversible CO2 absorption, whereas oxygen-based anions with moderate nucleophilicity mostly show reversible pressure-switchable behavior. Ab initio molecular dynamics simulations of a representative ionic liquid system confirmed pressureactivated CO2 absorption at the dynamic condensed-phase level. The pressure-induced CO2 absorption mechanism was further validated using the switchable solvent N,Ndimethylethanolamine, which is known to bind CO2 reversibly with the application of pressure. These results provide molecular-level insights into pressure-induced CO2 absorption and establish design principles for tailoring ionic liquids specifically for tunable, energy-efficient CO2 capture applications.
ER -