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Salman M, Lee JW, Lee SH, Lee MH, Pham VD, Kim MS, Cho D, Lee HJ. A comparative study of ammonia solubility in imidazolium-based ionic liquids with different structural compositions. Heliyon 2024; 10:e24305. [PMID: 38293395 PMCID: PMC10826666 DOI: 10.1016/j.heliyon.2024.e24305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 01/05/2024] [Accepted: 01/05/2024] [Indexed: 02/01/2024] Open
Abstract
Four imidazolium-based ionic liquids (ILs) with two cations 1-pentyl-3-butylimidazolium [PBIM]+ and 1-benzyl-3-butylimidazolium tetrafluoroborate [BzBIM]+, and two anions tetrafluoroborate (BF4-) and trifluoromethanesulfonate (OTf-) were synthesized for NH3 solubility enhancement. The structural, thermal, and electrochemical stabilities, ionic conductivity, and viscosity of the four ILs, namely, [PBIM]BF4, [BzBIM]BF4, [PBIM]OTf, and [BzBIM]OTf, were investigated. Due to the intermolecular interaction of the benzyl group attached to the imidazolium ring, [BzBIM]+-based ILs exhibited higher thermal stability but lower ionic conductivity compared to [PBIM]+-based ILs. Further, the NH3 solubility in all ILs was measured using a custom-made setup at temperatures ranging from 293.15 to 323.15 K and pressures ranging from 1 to 5 bar. The effects of the cation and anion structures of ILs, as well as pressure and temperature, on the NH3 solubility in the ILs were also investigated. [PBIM]BF4 showed the best solubility because of its high free volume and low viscosity. Density functional calculations validated the superior NH3 solubility in [PBIM]BF4, attributable to the minimal reorganization of the [cation]anion complex geometry during the solvation process, yielding a low solvation free energy. The findings of this study suggest that ILs exhibit a high NH3 solubility capacity and cation and anion structures considerably affect the NH3 solubility in ILs.
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Affiliation(s)
- Muhammad Salman
- Department of Chemistry and Green-Nano Materials Research Center, Kyungpook National University, 80 Daehakro, Buk-gu, Daegu-city, 41566, Republic of Korea
| | - Ji Won Lee
- Department of Chemistry and Green-Nano Materials Research Center, Kyungpook National University, 80 Daehakro, Buk-gu, Daegu-city, 41566, Republic of Korea
| | - Sang Hyuk Lee
- Department of Chemistry and Green-Nano Materials Research Center, Kyungpook National University, 80 Daehakro, Buk-gu, Daegu-city, 41566, Republic of Korea
| | - Min Ho Lee
- Department of Chemistry and Green-Nano Materials Research Center, Kyungpook National University, 80 Daehakro, Buk-gu, Daegu-city, 41566, Republic of Korea
| | - Van Duc Pham
- Department of New Biology, DGIST, Daegu, 42988, Republic of Korea
| | - Min-Sik Kim
- Department of New Biology, DGIST, Daegu, 42988, Republic of Korea
- New Biology Research Center, DGIST, Daegu, 42988, Republic of Korea
| | - Daeheum Cho
- Department of Chemistry and Green-Nano Materials Research Center, Kyungpook National University, 80 Daehakro, Buk-gu, Daegu-city, 41566, Republic of Korea
| | - Hye Jin Lee
- Department of Chemistry and Green-Nano Materials Research Center, Kyungpook National University, 80 Daehakro, Buk-gu, Daegu-city, 41566, Republic of Korea
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