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Das I, Rama Swami K, Gardas RL. Influence of alkyl substituent on thermophysical properties and CO2 absorption studies of diethylenetriamine- based ionic liquids. J Mol Liq 2023. [DOI: 10.1016/j.molliq.2022.121114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Zhang Y, Zhang X, Tang S, Wang Y, Li H, Mochizuki K, Yao J. Relationship between Structure and Properties of Nonstoichiometric Protic Ionic Liquids: n-Butylammonium Butyrate System. J Phys Chem Lett 2022; 13:10107-10113. [PMID: 36269300 DOI: 10.1021/acs.jpclett.2c02526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Nonstoichiometric protic ionic liquids have drawn much attention in applications, including fuel cells, batteries, and reaction media. An understanding of the relationship between their structure and properties is instructive for further applications. However, there are only a few studies on nonstoichiometric protic ionic liquids. Herein, the density, viscosity, and conductivity of nonstoichiometric n-butylammonium butyrate protic ionic liquids were measured, and we used small/wide-angle scattering (S/WAXS), electron paramagnetic resonance (EPR), and molecular dynamics (MD) simulation to explore the effect of mesostructure on their properties. It is found that the hydrogen bonds drive excess N-butyric acid (PrCOOH) molecules to wrap around ion clusters, resulting in the higher density and viscosity of PrCOOH-rich PILs. The microenvironments around various radicals differ significantly in BuNH2-rich and PrCOOH-rich PILs because of the distinct molecular arrangements. This research provided a link between the physicochemical properties and structures of nonstoichiometric PILs, which is essential for their applications in electrolytes and organic reactions.
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Affiliation(s)
- Yue Zhang
- Department of Chemistry, Zhejiang University, Hangzhou 310027, P.R. China
- ZJU-NHU United R&D Center, Zhejiang University, Hangzhou 310027, P.R. China
| | - Xuan Zhang
- Department of Chemistry, Zhejiang University, Hangzhou 310027, P.R. China
| | - Shiyi Tang
- Department of Chemistry, Zhejiang University, Hangzhou 310027, P.R. China
| | - Yongtao Wang
- Department of Chemistry, Zhejiang University, Hangzhou 310027, P.R. China
- ZJU-NHU United R&D Center, Zhejiang University, Hangzhou 310027, P.R. China
| | - Haoran Li
- Department of Chemistry, Zhejiang University, Hangzhou 310027, P.R. China
- ZJU-NHU United R&D Center, Zhejiang University, Hangzhou 310027, P.R. China
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, P.R. China
| | - Kenji Mochizuki
- Department of Chemistry, Zhejiang University, Hangzhou 310027, P.R. China
| | - Jia Yao
- Department of Chemistry, Zhejiang University, Hangzhou 310027, P.R. China
- ZJU-NHU United R&D Center, Zhejiang University, Hangzhou 310027, P.R. China
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Experimental Investigation on Thermophysical Properties of Ammonium-Based Protic Ionic Liquids and Their Potential Ability towards CO 2 Capture. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27030851. [PMID: 35164113 PMCID: PMC8839255 DOI: 10.3390/molecules27030851] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 01/23/2022] [Accepted: 01/24/2022] [Indexed: 11/29/2022]
Abstract
Ionic liquids, which are extensively known as low-melting-point salts, have received significant attention as the promising solvent for CO2 capture. This work presents the synthesis, thermophysical properties and the CO2 absorption of a series of ammonium cations coupled with carboxylate anions producing ammonium-based protic ionic liquids (PILs), namely 2-ethylhexylammonium pentanoate ([EHA][C5]), 2-ethylhexylammonium hexanoate ([EHA][C6]), 2-ethylhexylammonium heptanoate ([EHA][C7]), bis-(2-ethylhexyl)ammonium pentanoate ([BEHA][C5]), bis-(2-ethylhexyl)ammonium hexanoate ([BEHA][C6]) and bis-(2-ethylhexyl)ammonium heptanoate ([BEHA][C7]). The chemical structures of the PILs were confirmed by using Nuclear Magnetic Resonance (NMR) spectroscopy while the density (ρ) and the dynamic viscosity (η) of the PILs were determined and analyzed in a range from 293.15K up to 363.15K. The refractive index (nD) was also measured at T = (293.15 to 333.15) K. Thermal analyses conducted via a thermogravimetric analyzer (TGA) and differential scanning calorimeter (DSC) indicated that all PILs have the thermal decomposition temperature, Td of greater than 416K and the presence of glass transition, Tg was detected in each PIL. The CO2 absorption of the PILs was studied up to 29 bar at 298.15 K and the experimental results showed that [BEHA][C7] had the highest CO2 absorption with 0.78 mol at 29 bar. The CO2 absorption values increase in the order of [C5] < [C6] < [C7] anion regardless of the nature of the cation.
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Thermophysical Properties of Newly Synthesized Ammonium-Based Protic Ionic Liquids: Effect of Temperature, Anion and Alkyl Chain Length. Processes (Basel) 2020. [DOI: 10.3390/pr8060742] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Ionic liquids which are often classified as low melting point salts have received significant attention from research groups and industries to be used in a wide range of applications. Many of these applications require thorough knowledge on the thermophysical properties of the ionic liquids before utilizing their full potentials in various fields. In this work, a series of alkylammonium cation and carboxylate anion-based room temperature protic ionic liquids (PILs) were synthesized by varying length of alkyl chain of the cation from diethyl to dibutyl combined with pentanoate, hexanoate and heptanoate anions. These ammonium-based PILs named as diethylammonium pentanoate [DEA][C5], diethylammonium hexanoate [DEA][C6], diethylammonium heptanoate [DEA][C7], dibutylammonium pentanoate [DBA][C5], dibutylammonium hexanoate [DBA][C6] and dibutylammonium heptanoate [DBA][C7] were characterized using Nuclear Magnetic Resonance (NMR) spectroscopy. The thermophysical properties of the PILs namely density, dynamic viscosity and refractive index were measured and analyzed. Density, ρ and dynamic viscosity, η were determined at T = (293.15 to 363.15) K and refractive index, nD was measured at T = (293.15 to 333.15) K. The fitting parameters are proposed for the empirical correlations of density, dynamic viscosity and refractive index. The values of thermal expansion coefficient, αp, molecular volume, Vm, standard entropy, S° and lattice potential energy, Upot also have been calculated by using the specified equations. The thermal decomposition temperature, Td was also determined using a thermogravimetric analyzer (TGA) while the differential scanning calorimetry (DSC) technique provided the glass transition, Tg, melting point, Tm and crystallization, Tc temperatures of the PILs. The experimental results revealed that the dependency of the experimental values namely the ρ, η, nD, and Td on the alkyl chain of the anion, size of the cations and the temperature of measurement.
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Thermophysical Properties and CO2 Absorption of Ammonium-Based Protic Ionic Liquids Containing Acetate and Butyrate Anions. Processes (Basel) 2019. [DOI: 10.3390/pr7110820] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Ionic liquids, which are classified as new solvents, have been identified to be potential solvents in the application of CO2 capture. In this work, six ammonium-based protic ionic liquids, containing ethanolammonium [EtOHA], tributylammonium [TBA], bis(2-ethylhexyl)ammonium [BEHA] cations, and acetate [AC] and butyrate [BA] anions, were synthesized and characterized. The thermophysical properties of the ammonium-based protic ionic liquids were measured. Density, , and dynamic viscosity, , were determined at temperatures between 293.15 K and 363.15 K. The density and viscosity values were correlated using empirical correlations and the thermal coefficient expansion, p, and molecular volume, Vm, were estimated using density values. The thermal stability of the ammonium-based protic ionic liquids was investigated using thermogravimetric analyzer (TGA) at a heating rate of 10 C.min‒1. The CO2 absorption of the ammonium-based ionic liquids were measured up to 20 bar at 298.15 K. From the experimental results, [BEHA][BA] had the highest affinity towards CO2 with the mol fraction of CO2 absorbed approaching 0.5 at 20 bar. Generally, ionic liquids with butyrate anions have better CO2 absorption than that of acetate anions while [BEHA] ionic liquids have higher affinity towards CO2 followed by [TBA] and [EtOHA] ionic liquids.
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Kumar H, Katal A. Temperature dependent physicochemical and spectroscopic (FT-IR) studies of citrate salts (trilithium citrate and triammonium citrate) in aqueous ionic liquid [C 4 mim][BF 4 ] (1-butyl-3-methyl imidazolium tetrafluroborate) solutions. J Mol Liq 2018. [DOI: 10.1016/j.molliq.2018.02.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Spectroscopic and temperature dependent physicochemical studies on interactional behavior of phosphate salts in aqueous ionic liquid (1-butyl-3-methyl imidazolium tetrafluoroborate) solutions. J Mol Liq 2018. [DOI: 10.1016/j.molliq.2017.12.092] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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