Abstract
The deployment of transformational nonaqueous CO2-capture solvent systems is encumbered by high viscosities even at intermediate uptakes. Using single-molecule CO2 binding organic liquids as a prototypical example, we present key molecular features that control bulk viscosity. Fast CO2-uptake kinetics arise from close proximity of the alcohol and amine sites involved in CO2 binding in a concerted fashion, resulting in a Zwitterion containing both an alkyl-carbonate and a protonated amine. The population of internal hydrogen bonds between the two functional groups determines the solution viscosity. Unlike the ion pair interactions in ionic liquids, these observations are novel and specific to a hydrogen-bonding network that can be controlled by chemically tuning single molecule CO2 capture solvents. We present a molecular design strategy to reduce viscosity by shifting the proton transfer equilibrium toward a neutral acid/amine species, as opposed to the ubiquitously accepted zwitterionic state. The molecular design concepts proposed here are readily extensible to other CO2 capture technologies.
| Original language | English |
|---|---|
| Pages (from-to) | 1646-1652 |
| Number of pages | 7 |
| Journal | Journal of Physical Chemistry Letters |
| Volume | 7 |
| Issue number | 9 |
| DOIs | |
| Publication status | Published - May 5 2016 |
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ASJC Scopus subject areas
- Materials Science(all)
Cite this
Dynamic Acid/Base Equilibrium in Single Component Switchable Ionic Liquids and Consequences on Viscosity. / Cantu, David C.; Lee, Juntaek; Lee, Mal Soon; Heldebrant, David J.; Koech, Phillip K.; Freeman, Charles J.; Rousseau, Roger; Glezakou, Vassiliki Alexandra.
In: Journal of Physical Chemistry Letters, Vol. 7, No. 9, 05.05.2016, p. 1646-1652.Research output: Contribution to journal › Article
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TY - JOUR
T1 - Dynamic Acid/Base Equilibrium in Single Component Switchable Ionic Liquids and Consequences on Viscosity
AU - Cantu, David C.
AU - Lee, Juntaek
AU - Lee, Mal Soon
AU - Heldebrant, David J.
AU - Koech, Phillip K.
AU - Freeman, Charles J.
AU - Rousseau, Roger
AU - Glezakou, Vassiliki Alexandra
PY - 2016/5/5
Y1 - 2016/5/5
N2 - The deployment of transformational nonaqueous CO2-capture solvent systems is encumbered by high viscosities even at intermediate uptakes. Using single-molecule CO2 binding organic liquids as a prototypical example, we present key molecular features that control bulk viscosity. Fast CO2-uptake kinetics arise from close proximity of the alcohol and amine sites involved in CO2 binding in a concerted fashion, resulting in a Zwitterion containing both an alkyl-carbonate and a protonated amine. The population of internal hydrogen bonds between the two functional groups determines the solution viscosity. Unlike the ion pair interactions in ionic liquids, these observations are novel and specific to a hydrogen-bonding network that can be controlled by chemically tuning single molecule CO2 capture solvents. We present a molecular design strategy to reduce viscosity by shifting the proton transfer equilibrium toward a neutral acid/amine species, as opposed to the ubiquitously accepted zwitterionic state. The molecular design concepts proposed here are readily extensible to other CO2 capture technologies.
AB - The deployment of transformational nonaqueous CO2-capture solvent systems is encumbered by high viscosities even at intermediate uptakes. Using single-molecule CO2 binding organic liquids as a prototypical example, we present key molecular features that control bulk viscosity. Fast CO2-uptake kinetics arise from close proximity of the alcohol and amine sites involved in CO2 binding in a concerted fashion, resulting in a Zwitterion containing both an alkyl-carbonate and a protonated amine. The population of internal hydrogen bonds between the two functional groups determines the solution viscosity. Unlike the ion pair interactions in ionic liquids, these observations are novel and specific to a hydrogen-bonding network that can be controlled by chemically tuning single molecule CO2 capture solvents. We present a molecular design strategy to reduce viscosity by shifting the proton transfer equilibrium toward a neutral acid/amine species, as opposed to the ubiquitously accepted zwitterionic state. The molecular design concepts proposed here are readily extensible to other CO2 capture technologies.
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U2 - 10.1021/acs.jpclett.6b00395
DO - 10.1021/acs.jpclett.6b00395
M3 - Article
AN - SCOPUS:84968854052
VL - 7
SP - 1646
EP - 1652
JO - Journal of Physical Chemistry Letters
JF - Journal of Physical Chemistry Letters
SN - 1948-7185
IS - 9
ER -