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Dunaev AM, Motalov VB, Kudin LS. The Composition of Saturated Vapor over 1-Butyl-3-methylimidazolium Tetrafluoroborate Ionic Liquid: A Multi-Technique Study of the Vaporization Process. ENTROPY 2021; 23:e23111478. [PMID: 34828176 PMCID: PMC8625100 DOI: 10.3390/e23111478] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 10/26/2021] [Accepted: 10/29/2021] [Indexed: 11/16/2022]
Abstract
A multi-technique approach based on Knudsen effusion mass spectrometry, gas phase chromatography, mass spectrometry, NMR and IR spectroscopy, thermal analysis, and quantum-chemical calculations was used to study the evaporation of 1-butyl-3-methylimidazolium tetrafluoroborate (BMImBF4). The saturated vapor over BMImBF4 was shown to have a complex composition which consisted of the neutral ion pairs (NIPs) [BMIm+][BF4-], imidazole-2-ylidene C8N2H14BF3, 1-methylimidazole C4N2H6, 1-butene C4H8, hydrogen fluoride HF, and boron trifluoride BF3. The vapor composition strongly depends on the evaporation conditions, shifting from congruent evaporation in the form of NIP under Langmuir conditions (open surface) to primary evaporation in the form of decomposition products under equilibrium conditions (Knudsen cell). Decomposition into imidazole-2-ylidene and HF is preferred. The vapor composition of BMImBF4 is temperature-depended as well: the fraction ratio of [BMIm+][BF4-] NIPs to decomposition products decreased by about a factor of three in the temperature range from 450 K to 510 K.
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Seymour JM, Gousseva E, Large AI, Clarke CJ, Licence P, Fogarty RM, Duncan DA, Ferrer P, Venturini F, Bennett RA, Palgrave RG, Lovelock KRJ. Experimental measurement and prediction of ionic liquid ionisation energies. Phys Chem Chem Phys 2021; 23:20957-20973. [PMID: 34545382 DOI: 10.1039/d1cp02441h] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ionic liquid (IL) valence electronic structure provides key descriptors for understanding and predicting IL properties. The ionisation energies of 60 ILs are measured and the most readily ionised valence state of each IL (the highest occupied molecular orbital, HOMO) is identified using a combination of X-ray photoelectron spectroscopy (XPS) and synchrotron resonant XPS. A structurally diverse range of cations and anions were studied. The cation gave rise to the HOMO for nine of the 60 ILs presented here, meaning it is energetically more favourable to remove an electron from the cation than the anion. The influence of the cation on the anion electronic structure (and vice versa) were established; the electrostatic effects are well understood and demonstrated to be consistently predictable. We used this knowledge to make predictions of both ionisation energy and HOMO identity for a further 516 ILs, providing a very valuable dataset for benchmarking electronic structure calculations and enabling the development of models linking experimental valence electronic structure descriptors to other IL properties, e.g. electrochemical stability. Furthermore, we provide design rules for the prediction of the electronic structure of ILs.
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Affiliation(s)
- Jake M Seymour
- Department of Chemistry, University of Reading, Reading, RG6 6AD, UK.
| | | | - Alexander I Large
- Department of Chemistry, University of Reading, Reading, RG6 6AD, UK. .,Diamond Light Source, Didcot, Oxfordshire, OX11 0DE, UK
| | - Coby J Clarke
- School of Chemistry, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Peter Licence
- School of Chemistry, University of Nottingham, Nottingham, NG7 2RD, UK
| | | | | | - Pilar Ferrer
- Diamond Light Source, Didcot, Oxfordshire, OX11 0DE, UK
| | | | - Roger A Bennett
- Department of Chemistry, University of Reading, Reading, RG6 6AD, UK.
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Brown SJ, Drummond CJ, Marchand J, Marcuccio SM, Stockton KP, Greaves TL. Physicochemical characterisation of novel tetrabutylammonium aryltrifluoroborate ionic liquids. Phys Chem Chem Phys 2020; 22:23374-23384. [PMID: 33047742 DOI: 10.1039/d0cp03994b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
While there have been many studies on the physicochemical characterisation of ILs, little work has previously been reported on the properties unique to the trifluoroborate anion. Here we have characterised the thermal properties, viscosity, liquid nanostructure and intramolecular interactions of 15 novel aryltrifluoroborate ILs. These ILs all contained a tetrabutylammonium cation paired with either meta- or para-substituted aryltrifluoroborate anions, or di-anionic substituted aryltrifluroborate anions. It was found that of the 15 samples analysed, 4 would technically be considered molten salts as they have melting points greater than 100 °C. Overall the structure-property relationship trends of these samples are similar to those previously reported for alkyl and perfluoroalkyltrifluoroborate ILs which contained K+ or Cs+ cations, with the big difference being the ILs in this study having considerably lower melting points.
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Affiliation(s)
- Stuart J Brown
- College of Science, Engineering and Health, RMIT University, 124 La Trobe Street, Melbourne, Victoria, Australia.
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Clarke CJ, Bui-Le L, Corbett PJ, Hallett JP. Implications for Heavy Metal Extractions from Hyper Saline Brines with [NTf2]− Ionic Liquids: Performance, Solubility, and Cost. Ind Eng Chem Res 2019. [DOI: 10.1021/acs.iecr.9b04722] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Coby J. Clarke
- Department of Chemical Engineering, Imperial College London, London SW7 2AZ, U.K
| | - Liem Bui-Le
- Department of Chemical Engineering, Imperial College London, London SW7 2AZ, U.K
| | - Paul J. Corbett
- Shell International Limited, 40 Bank Street, London E14 5AB, U.K
| | - Jason P. Hallett
- Department of Chemical Engineering, Imperial College London, London SW7 2AZ, U.K
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Tracy C, Adler AM, Nguyen A, Johnson RD, Miller KM. Covalently Crosslinked 1,2,3-Triazolium-Containing Polyester Networks: Thermal, Mechanical, and Conductive Properties. ACS OMEGA 2018; 3:13442-13453. [PMID: 31458056 PMCID: PMC6644408 DOI: 10.1021/acsomega.8b01949] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Accepted: 10/05/2018] [Indexed: 05/05/2023]
Abstract
Azide-alkyne "click" cyclization was used to prepare a series of polymerizable acetoacetate monomers containing a 1,2,3-trizolium ionic liquid group. The monomers were subsequently polymerized using base-catalyzed Michael addition chemistry, producing a series of covalently crosslinked 1,2,3-triazolium poly(ionic liquid) (TPIL) networks. Structure-activity relationships were conducted to gauge how synthetic variables, such as counteranion ([Br], [NO3], [BF4], [OTf], and [NTf2]), and crosslink density (acrylate/acetoacetate ratio) effected thermal, mechanical, and conductive properties. TPIL networks were found to exhibit ionic conductivities in the range of 10-6-10-9 S/cm (30 °C, 30% relative humidity), as determined from dielectric relaxation spectroscopy, despite their highly crosslinked nature. Temperature-dependent conductivities demonstrate a dependence on polymer glass transition, with free-ion concentrations impacted by various ions' Lewis acidity/basicity and ion mobilities impacted by freely mobile anion size.
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Affiliation(s)
- Clayton
A. Tracy
- Department of Chemistry, Murray State University, 1201 Jesse D. Jones Hall, Murray, Kentucky 42071, United
States
| | - Abagail M. Adler
- Department of Chemistry, Murray State University, 1201 Jesse D. Jones Hall, Murray, Kentucky 42071, United
States
| | - Anh Nguyen
- Department of Chemistry, Murray State University, 1201 Jesse D. Jones Hall, Murray, Kentucky 42071, United
States
| | - R. Daniel Johnson
- Department of Chemistry, Murray State University, 1201 Jesse D. Jones Hall, Murray, Kentucky 42071, United
States
| | - Kevin M. Miller
- Department of Chemistry, Murray State University, 1201 Jesse D. Jones Hall, Murray, Kentucky 42071, United
States
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