CO<sub>2</sub> Absorption by Solvents Consisting of TMG Protic Ionic Liquids and Ethylene Glycol: The Influence of Hydrogen Bonds
Herein, the absorption of CO<sub>2</sub> by the TMG-based (TMG: 1,1,3,3-tetramethylguanidine) ionic liquids (ILs) and the absorbents formed by TMG ILs and ethylene glycol (EG) is studied. The TMG-based ILs used are formed by TMG and 4-fluorophenol (4-F-PhOH) or carvacrol (Car), and their...
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| Format: | Article |
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MDPI AG
2024-02-01
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| Series: | Atmosphere |
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| Online Access: | https://www.mdpi.com/2073-4433/15/2/229 |
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| author | Bohao Lu Yixing Zeng Mingzhe Chen Shaoze Zhang Dezhong Yang |
| author_facet | Bohao Lu Yixing Zeng Mingzhe Chen Shaoze Zhang Dezhong Yang |
| author_sort | Bohao Lu |
| collection | DOAJ |
| description | Herein, the absorption of CO<sub>2</sub> by the TMG-based (TMG: 1,1,3,3-tetramethylguanidine) ionic liquids (ILs) and the absorbents formed by TMG ILs and ethylene glycol (EG) is studied. The TMG-based ILs used are formed by TMG and 4-fluorophenol (4-F-PhOH) or carvacrol (Car), and their viscosities are low at 25 °C. The CO<sub>2</sub> uptake capacities of [TMGH][4-F-PhO] and [TMGH][Car] are low (~0.09 mol CO<sub>2</sub>/mol IL) at 25 °C and 1.0 atm. However, the mixtures [TMGH][4-F-PhO]-EG and [TMGH][Car]-EG show much higher capacities (~1.0 mol CO<sub>2</sub>/mol IL) than those of parent ILs, which is unexpected because of the low CO<sub>2</sub> capacity of EG (0.01 mol CO<sub>2</sub>/mol EG) in the same conditions. NMR spectra and theoretical calculations are used to determine the reason for these unexpected absorption behaviors. The spectra and theoretical results show that the strong hydrogen bonds between the [TMGH]<sup>+</sup> cation and the phenolate anions make the used TMG-based ILs unreactive to CO<sub>2</sub>, resulting in the low CO<sub>2</sub> capacity. In the Ils-EG mixtures, the hydrogen bonds formed between EG and phenolate anions can weaken the [TMGH]<sup>+</sup>–anion hydrogen bond strength, so ILs-EG mixtures can react with CO<sub>2</sub> and present high CO<sub>2</sub> capacities. |
| first_indexed | 2024-03-07T22:42:33Z |
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| issn | 2073-4433 |
| language | English |
| last_indexed | 2024-03-07T22:42:33Z |
| publishDate | 2024-02-01 |
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| record_format | Article |
| series | Atmosphere |
| spelling | doaj.art-51a403cd5e9648aabf3c2d807c47c6a82024-02-23T15:07:13ZengMDPI AGAtmosphere2073-44332024-02-0115222910.3390/atmos15020229CO<sub>2</sub> Absorption by Solvents Consisting of TMG Protic Ionic Liquids and Ethylene Glycol: The Influence of Hydrogen BondsBohao Lu0Yixing Zeng1Mingzhe Chen2Shaoze Zhang3Dezhong Yang4School of Science, China University of Geosciences, Beijing 100083, ChinaNational Engineering Research Center of Vacuum Metallurgy, Kunming University of Science and Technology, Kunming 650093, ChinaSchool of Science, China University of Geosciences, Beijing 100083, ChinaNational Engineering Research Center of Vacuum Metallurgy, Kunming University of Science and Technology, Kunming 650093, ChinaSchool of Science, China University of Geosciences, Beijing 100083, ChinaHerein, the absorption of CO<sub>2</sub> by the TMG-based (TMG: 1,1,3,3-tetramethylguanidine) ionic liquids (ILs) and the absorbents formed by TMG ILs and ethylene glycol (EG) is studied. The TMG-based ILs used are formed by TMG and 4-fluorophenol (4-F-PhOH) or carvacrol (Car), and their viscosities are low at 25 °C. The CO<sub>2</sub> uptake capacities of [TMGH][4-F-PhO] and [TMGH][Car] are low (~0.09 mol CO<sub>2</sub>/mol IL) at 25 °C and 1.0 atm. However, the mixtures [TMGH][4-F-PhO]-EG and [TMGH][Car]-EG show much higher capacities (~1.0 mol CO<sub>2</sub>/mol IL) than those of parent ILs, which is unexpected because of the low CO<sub>2</sub> capacity of EG (0.01 mol CO<sub>2</sub>/mol EG) in the same conditions. NMR spectra and theoretical calculations are used to determine the reason for these unexpected absorption behaviors. The spectra and theoretical results show that the strong hydrogen bonds between the [TMGH]<sup>+</sup> cation and the phenolate anions make the used TMG-based ILs unreactive to CO<sub>2</sub>, resulting in the low CO<sub>2</sub> capacity. In the Ils-EG mixtures, the hydrogen bonds formed between EG and phenolate anions can weaken the [TMGH]<sup>+</sup>–anion hydrogen bond strength, so ILs-EG mixtures can react with CO<sub>2</sub> and present high CO<sub>2</sub> capacities.https://www.mdpi.com/2073-4433/15/2/229carbon dioxideionic liquidshydrogen bondsabsorptionethylene glycol |
| spellingShingle | Bohao Lu Yixing Zeng Mingzhe Chen Shaoze Zhang Dezhong Yang CO<sub>2</sub> Absorption by Solvents Consisting of TMG Protic Ionic Liquids and Ethylene Glycol: The Influence of Hydrogen Bonds Atmosphere carbon dioxide ionic liquids hydrogen bonds absorption ethylene glycol |
| title | CO<sub>2</sub> Absorption by Solvents Consisting of TMG Protic Ionic Liquids and Ethylene Glycol: The Influence of Hydrogen Bonds |
| title_full | CO<sub>2</sub> Absorption by Solvents Consisting of TMG Protic Ionic Liquids and Ethylene Glycol: The Influence of Hydrogen Bonds |
| title_fullStr | CO<sub>2</sub> Absorption by Solvents Consisting of TMG Protic Ionic Liquids and Ethylene Glycol: The Influence of Hydrogen Bonds |
| title_full_unstemmed | CO<sub>2</sub> Absorption by Solvents Consisting of TMG Protic Ionic Liquids and Ethylene Glycol: The Influence of Hydrogen Bonds |
| title_short | CO<sub>2</sub> Absorption by Solvents Consisting of TMG Protic Ionic Liquids and Ethylene Glycol: The Influence of Hydrogen Bonds |
| title_sort | co sub 2 sub absorption by solvents consisting of tmg protic ionic liquids and ethylene glycol the influence of hydrogen bonds |
| topic | carbon dioxide ionic liquids hydrogen bonds absorption ethylene glycol |
| url | https://www.mdpi.com/2073-4433/15/2/229 |
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