Relationship between Diffusion and Chemical Exchange in Mixtures of Carbon Dioxide and an Amine-Functionalized Ionic Liquid by High Field NMR and Kinetic Monte Carlo Simulations.
NMR exchange spectroscopy (EXSY) and NMR diffusion spectroscopy (PFG NMR) were applied in combination with kinetic Monte Carlo (MC) simulations to investigate self-diffusion in a mixture of carbon dioxide and an amine-functionalized ionic liquid under conditions of an exchange of carbon dioxide molecules between the reacted and unreacted states in the mixture. EXSY studies enabled residence times of carbon dioxide molecules to be obtained in the two states, whereas PFG NMR revealed time-dependent effective diffusivities for diffusion times comparable with and larger than the residence times. Analytical treatment of the PFG NMR attenuation curves as well as fitting of the PFG NMR effective diffusivities by KMC simulations enabled determination of diffusivities of carbon dioxide in the reacted and unreacted states. In contrast to carbon dioxide, the ion diffusivities were found to be diffusion time independent.
†Department of Chemical Engineering, University of Florida, Gainesville, Florida 32611, United States.
Eric D
ED
Hazelbaker
‡Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana 46556, United States.
Samir
S
Budhathoki
†Department of Chemical Engineering, University of Florida, Gainesville, Florida 32611, United States.
Han
H
Wang
‡Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana 46556, United States.|§The Center for Research Computing, University of Notre Dame, Notre Dame, Indiana 46556, United States.
Jindal
J
Shah
‡Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana 46556, United States.
Edward J
EJ
Maginn
†Department of Chemical Engineering, University of Florida, Gainesville, Florida 32611, United States.
Sergey
S
Vasenkov
Kinetic Monte Carlo Simulations; NMR; carbon dioxide capture; diffusion; task-specific ionic liquid