1
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Emerson M, Ivanov AS, Gallington LC, Maltsev DS, Halstenberg P, Dai S, Roy S, Bryantsev VS, Margulis CJ. Heterogeneous Structure, Mechanisms of Counterion Exchange, and the Spacer Salt Effect in Complex Molten Salt Mixtures Including LaCl 3. J Phys Chem B 2024; 128:3972-3980. [PMID: 38624173 PMCID: PMC11056984 DOI: 10.1021/acs.jpcb.4c01429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 03/22/2024] [Accepted: 03/26/2024] [Indexed: 04/17/2024]
Abstract
Complex molten chloride salt mixtures of uranium, magnesium, and sodium are top candidates for promising nuclear energy technologies to produce electricity based on molten salt reactors. From a local structural perspective, LaCl3 is similar to UCl3 and hence a good proxy to study these complex salt mixtures. As fission products, lanthanide salts and their mixtures are also very important in their own right. This article describes from an experimental and theory perspective how very different the structural roles of MgCl2 and NaCl are in mixtures with LaCl3. We find that, whereas MgCl2 becomes an integral part of multivalent ionic networks, NaCl separates them. In a recent article (J. Am. Chem. Soc. 2022, 144, 21751-21762) we have called the disruptive behavior of NaCl "the spacer salt effect". Because of the heterogeneous nature of these salt mixtures, there are multiple structural motifs in the melt, each with its particular free energetics. Our work identifies and quantifies these; it also elucidates the mechanisms through which Cl- ions exchange between Mg2+-rich and La3+-rich environments.
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Affiliation(s)
- Matthew
S. Emerson
- Department
of Chemistry, The University of Iowa, Iowa City, Iowa 52242, United States
| | - Alexander S. Ivanov
- Chemical
Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | | | - Dmitry S. Maltsev
- Chemical
Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Phillip Halstenberg
- Chemical
Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Department
of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Sheng Dai
- Chemical
Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Department
of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Santanu Roy
- Chemical
Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Vyacheslav S. Bryantsev
- Chemical
Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Claudio J. Margulis
- Department
of Chemistry, The University of Iowa, Iowa City, Iowa 52242, United States
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2
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Rauber D, Philippi F, Schroeder D, Morgenstern B, White AJP, Jochum M, Welton T, Kay CWM. Room temperature ionic liquids with two symmetric ions. Chem Sci 2023; 14:10340-10346. [PMID: 37772103 PMCID: PMC10530934 DOI: 10.1039/d3sc03240j] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Accepted: 08/31/2023] [Indexed: 09/30/2023] Open
Abstract
Room temperature ionic liquids typically contain asymmetric organic cations. The asymmetry is thought to enhance disorder, thereby providing an entropic counter-balance to the strong, enthalpic, ionic interactions, and leading, therefore, to lower melting points. Unfortunately, the synthesis and purification of such asymmetric cations is typically more demanding. Here we introduce novel room temperature ionic liquids in which both cation and anion are formally symmetric. The chemical basis for this unprecedented behaviour is the incorporation of ether-containing side chains - which increase the configurational entropy - in the cation. Molecular dynamics simulations indicate that the ether-containing side chains transiently sample curled configurations. Our results contradict the long-standing paradigm that at least one asymmetric ion is required for ionic liquids to be molten at room temperature, and hence open up new and simpler design pathways for these remarkable materials.
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Affiliation(s)
- Daniel Rauber
- Department of Chemistry, Saarland University Campus B 2.2 66123 Saarbrücken Germany
| | - Frederik Philippi
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, White City Campus London W12 0BZ UK
| | - Daniel Schroeder
- Department of Chemistry, Saarland University Campus B 2.2 66123 Saarbrücken Germany
| | - Bernd Morgenstern
- Department of Chemistry, Saarland University Campus B 2.2 66123 Saarbrücken Germany
| | - Andrew J P White
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, White City Campus London W12 0BZ UK
| | - Marlon Jochum
- INM-Leibniz Institute for New Materials Campus D2.2 66123 Saarbrücken Germany
| | - Tom Welton
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, White City Campus London W12 0BZ UK
| | - Christopher W M Kay
- Department of Chemistry, Saarland University Campus B 2.2 66123 Saarbrücken Germany
- London Centre for Nanotechnology, University College London 17-19 Gordon Street London WC1H 0AH UK
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3
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Karunaratne W, Zhao M, Castner EW, Margulis CJ. Vacuum Interfacial Structure and X-ray Reflectivity of Imidazolium-Based Ionic Liquids with Perfluorinated Anions from a Theory and Simulations Perspective. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2022; 126:13936-13945. [PMID: 36017361 PMCID: PMC9394757 DOI: 10.1021/acs.jpcc.2c03311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 07/22/2022] [Indexed: 06/15/2023]
Abstract
We report studies of the vacuum interfacial structure of a series of 1-methyl-3-alkylimidazolium bis(perfluoroalkanesulfonyl)imide ionic liquids (ILs) and predict and explain their Fresnel-normalized X-ray reflectivity. To better interpret the results, we use a theory we recently developed dubbed "the peaks and antipeaks analysis of reflectivity" which splits the overall signal into that of different pair subcomponents. Whereas the overall reflectivity signal is not very informative, the peak and trough intensities for the pair subcomponents provide rich information for analysis. When species containing cationic alkyl or anionic fluoroalkyl tails are present at the interface, a tail layer is found next to a vacuum, and this tail layer can be composed of both alkyl and fluoroalkyl moieties. To maintain the positive-negative alternation of charged groups, alkyl and fluoroalkyl tails must necessarily be nearby and cannot segregate. Charged groups are found in the subsequent layer just below the interface and arranged to achieve lateral charge neutrality. In general, fluctuations at and away from the interface are based on polarity (i.e., heads and tails) and not on charge; when there are no significant alkyl or fluoroalkyl moieties in the IL, atomic density fluctuations away from the interface are small and appear to exist for the purpose of achieving lateral charge balance. For all the systems reported here, the persistence length of density fluctuations does not go beyond ∼7 nm.
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Affiliation(s)
| | - Man Zhao
- Department
of Chemistry and Chemical Biology, Rutgers,
The State University of New Jersey, Piscataway, New Jersey 08854, United States
| | - Edward W. Castner
- Department
of Chemistry and Chemical Biology, Rutgers,
The State University of New Jersey, Piscataway, New Jersey 08854, United States
| | - Claudio J. Margulis
- Department
of Chemistry, University of Iowa, Iowa City, Iowa 52242, United States
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4
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Amith WD, Araque JC, Margulis CJ. Relationship between the Relaxation of Ionic Liquid Structural Motifs and That of the Shear Viscosity. J Phys Chem B 2021; 125:6264-6271. [PMID: 34097825 PMCID: PMC8279556 DOI: 10.1021/acs.jpcb.1c03105] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
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In a set of recent
articles, we have highlighted that friction
is highly inhomogeneous in a typical ionic liquid (IL) with charge
networks that are stiff and charge-depleted regions that are soft.
This has consequences not only for the dynamics of ILs but also for the transport properties of solutes
dissolved in them. In this article, we explore whether the family
of alkylimidazolium ILs coupled with bis(trifluoromethylsulfonyl)imide
(with similar Coulombic interactions but different alkyl tails), when
dynamically “equalized” by having a similar shear viscosity,
display q-dependent structural relaxation time scales
that are the same across the family. Our results show that this is
not the case, and in fact, the relaxation of in-network charge alternation
appears to be significantly affected by the presence of separate polar
and apolar domains. However, we also find that if one was to assign
weight factors to the relaxation of the structural motifs, charge
alternation always contributes about the same amount (between 62.1
and 66.3%) across systems to the running integral of the stress tensor
correlation function from which the shear viscosity is derived. Adjacency
correlations between positive and negative moieties also contribute
an identical amount if a prepeak is not present (about 38%) and a
slightly smaller amount (about 28%) when intermediate range order
exists. The prepeak only contributes about 6% to viscoelastic relaxation,
highlighting that the dynamics of the smaller scale motifs is the
most important.
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Affiliation(s)
| | - Juan C Araque
- School of Engineering, Benedictine College, Atchison, Kansas 66002, United States
| | - Claudio J Margulis
- Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, United States
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5
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Wang YL, Li B, Sarman S, Mocci F, Lu ZY, Yuan J, Laaksonen A, Fayer MD. Microstructural and Dynamical Heterogeneities in Ionic Liquids. Chem Rev 2020; 120:5798-5877. [PMID: 32292036 PMCID: PMC7349628 DOI: 10.1021/acs.chemrev.9b00693] [Citation(s) in RCA: 219] [Impact Index Per Article: 43.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Indexed: 12/11/2022]
Abstract
Ionic liquids (ILs) are a special category of molten salts solely composed of ions with varied molecular symmetry and charge delocalization. The versatility in combining varied cation-anion moieties and in functionalizing ions with different atoms and molecular groups contributes to their peculiar interactions ranging from weak isotropic associations to strong, specific, and anisotropic forces. A delicate interplay among intra- and intermolecular interactions facilitates the formation of heterogeneous microstructures and liquid morphologies, which further contributes to their striking dynamical properties. Microstructural and dynamical heterogeneities of ILs lead to their multifaceted properties described by an inherent designer feature, which makes ILs important candidates for novel solvents, electrolytes, and functional materials in academia and industrial applications. Due to a massive number of combinations of ion pairs with ion species having distinct molecular structures and IL mixtures containing varied molecular solvents, a comprehensive understanding of their hierarchical structural and dynamical quantities is of great significance for a rational selection of ILs with appropriate properties and thereafter advancing their macroscopic functionalities in applications. In this review, we comprehensively trace recent advances in understanding delicate interplay of strong and weak interactions that underpin their complex phase behaviors with a particular emphasis on understanding heterogeneous microstructures and dynamics of ILs in bulk liquids, in mixtures with cosolvents, and in interfacial regions.
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Affiliation(s)
- Yong-Lei Wang
- Department
of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Bin Li
- School
of Chemical Engineering and Technology, Sun Yat-sen University, Zhuhai 519082, P. R. China
| | - Sten Sarman
- Department
of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Francesca Mocci
- Department
of Chemical and Geological Sciences, University
of Cagliari, I-09042 Monserrato, Italy
| | - Zhong-Yuan Lu
- State
Key Laboratory of Supramolecular Structure and Materials, Institute
of Theoretical Chemistry, Jilin University, Changchun 130021, P. R. China
| | - Jiayin Yuan
- Department
of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Aatto Laaksonen
- Department
of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
- State
Key Laboratory of Materials-Oriented and Chemical Engineering, Nanjing Tech University, Nanjing 210009, P. R. China
- Centre of
Advanced Research in Bionanoconjugates and Biopolymers, Petru Poni Institute of Macromolecular Chemistry Aleea Grigore Ghica-Voda, 41A, 700487 Iasi, Romania
- Department
of Engineering Sciences and Mathematics, Division of Energy Science, Luleå University of Technology, SE-97187 Luleå, Sweden
| | - Michael D. Fayer
- Department
of Chemistry, Stanford University, Stanford, California 94305, United States
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6
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Wu B, Breen JP, Xing X, Fayer MD. Controlling the Dynamics of Ionic Liquid Thin Films via Multilayer Surface Functionalization. J Am Chem Soc 2020; 142:9482-9492. [PMID: 32349470 DOI: 10.1021/jacs.0c03044] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The structural dynamics of planar thin films of an ionic liquid (IL) 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (BmimNTf2) as a function of surface charge density and thickness were investigated using two-dimensional infrared (2D IR) spectroscopy. The films were made by spin coating a methanol solution of the IL on silica substrates that were functionalized with alkyl chains containing head groups that mimic the IL cation. The thicknesses of the ionic liquid films ranged from ∼50 to ∼250 nm. The dynamics of the films are slower than those in the bulk IL, becoming increasingly slow as the films become thinner. Control of the dynamics of the IL films can be achieved by adjusting the charge density on substrates through multilayer network surface functionalization. The charge density of the surface (number of positively charged groups in the network bound to the surface per unit area) is controlled by the duration of the functionalization reaction. As the charge density is increased, the IL dynamics become slower. For comparison, the surface was functionalized with three different neutral groups. Dynamics of the IL films on the functionalized neutral surfaces are faster than on any of the ionic surfaces but still slower than the bulk IL, even for the thickest films. These results can have implications in applications that employ ILs that have electrodes, such as batteries, as the electrode surface charge density will influence properties like diffusion close to the surface.
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Affiliation(s)
- Boning Wu
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - John P Breen
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Xiangyu Xing
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Michael D Fayer
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
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7
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Roy S, Wu F, Wang H, Ivanov AS, Sharma S, Halstenberg P, Gill SK, Milinda Abeykoon AM, Kwon G, Topsakal M, Layne B, Sasaki K, Zhang Y, Mahurin SM, Dai S, Margulis CJ, Maginn EJ, Bryantsev VS. Structure and dynamics of the molten alkali-chloride salts from an X-ray, simulation, and rate theory perspective. Phys Chem Chem Phys 2020; 22:22900-22917. [DOI: 10.1039/d0cp03672b] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Molten salts are of great interest as alternative solvents, electrolytes, and heat transfer fluids in many emerging technologies.
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Affiliation(s)
- Santanu Roy
- Chemical Sciences Division
- Oak Ridge National Laboratory
- Oak Ridge
- USA
| | - Fei Wu
- Department of Chemistry
- The University of Iowa
- USA
| | - Haimeng Wang
- Department of Chemical and Biomolecular Engineering
- University of Notre Dame
- USA
| | | | | | - Phillip Halstenberg
- Chemical Sciences Division
- Oak Ridge National Laboratory
- Oak Ridge
- USA
- Department of Chemistry
| | - Simerjeet K Gill
- Nuclear Science and Technology Department
- Brookhaven National Lab
- USA
| | | | - Gihan Kwon
- National Synchrotron Light Source II (NSLS-II)
- Brookhaven National Lab
- USA
| | - Mehmet Topsakal
- Nuclear Science and Technology Department
- Brookhaven National Lab
- USA
| | - Bobby Layne
- Chemistry Division
- Brookhaven National Lab
- USA
| | | | - Yong Zhang
- Department of Chemical and Biomolecular Engineering
- University of Notre Dame
- USA
| | | | - Sheng Dai
- Chemical Sciences Division
- Oak Ridge National Laboratory
- Oak Ridge
- USA
- Department of Chemistry
| | | | - Edward J. Maginn
- Department of Chemical and Biomolecular Engineering
- University of Notre Dame
- USA
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8
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Poovathingal SJ, Minton TK, Szilagyi RK. Evaluating Density Functionals by Examining Molecular Structures, Chemical Bonding, and Relative Energies of Mononuclear Ru-Cl-H-PR 3 Isomers. J Phys Chem A 2019; 123:343-358. [PMID: 30540469 DOI: 10.1021/acs.jpca.8b03216] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In order to define a robust level of theory using density functionals for investigating the reactivity of ruthenium complexes, we used benchmark wave function theory, with saturated basis sets to validate generalized gradient approximation (GGA), meta-GGA, and hyper-GGA functionals in the presence and absence of empirical dispersion and range-separated corrections. We first selected potentially suitable functionals that gave accurate predictions of the relative energetics of coordination isomers. These functionals were further evaluated for the chemical accuracy of their predicted geometric and electronic structures. For the latter, both the ionic and covalent interactions were considered. The reference level of theory for comparison was coupled-cluster perturbation theory using full treatment of singles and doubles (CCSD) with a saturated triple-ζ quality basis set (TZVP) and corresponding small-core, effective core potentials for ruthenium. Several population analysis methods were evaluated to predict the ionic interactions. We found that the atomic charges obtained from fitting the electrostatic potential provided the most reasonable estimates for the ruthenium complexes. The covalent interactions were quantified by considering the atomic compositions of Ru 4d x2- y2- and 4d z2-based frontier unoccupied orbitals. Comparison of more than two dozen functionals with reference data from high-level wave function calculations revealed trends that allowed for the formulation of an optimal hybrid density functional: PBE exchange and correlation functionals with 50% HF exchange component. This level of theory was found to reproduce the experimental structure of Ru(II) complexes. These complexes were used to investigate chemical speciation in a simplified model for an ionic liquid environment.
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Affiliation(s)
- Savio J Poovathingal
- Department of Chemistry and Biochemistry , Montana State University , Bozeman , Montana 59717 , United States
| | - Timothy K Minton
- Department of Chemistry and Biochemistry , Montana State University , Bozeman , Montana 59717 , United States
| | - Robert K Szilagyi
- Department of Chemistry and Biochemistry , Montana State University , Bozeman , Montana 59717 , United States
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9
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Doughty B, Genix AC, Popov I, Li B, Zhao S, Saito T, Lutterman DA, Sacci RL, Sumpter BG, Wojnarowska Z, Bocharova V. Structural correlations tailor conductive properties in polymerized ionic liquids. Phys Chem Chem Phys 2019; 21:14775-14785. [DOI: 10.1039/c9cp02268f] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this paper, it was demonstrated that the mobile ion (anion) size and pendant group chemistry affect the packing of the polymer chains and influence conductivity in imidazolium based PolyILs.
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Affiliation(s)
- Benjamin Doughty
- Chemical Sciences Division
- Oak Ridge National Laboratory
- Oak Ridge
- USA
| | - Anne-Caroline Genix
- Laboratoire Charles Coulomb (L2C), Université de Montpellier
- CNRS
- F-34095 Montpellier
- France
| | - Ivan Popov
- Chemical Sciences Division
- Oak Ridge National Laboratory
- Oak Ridge
- USA
| | - Bingrui Li
- Department of Chemistry
- University of Tennessee
- Knoxville
- USA
| | - Sheng Zhao
- Department of Chemistry
- University of Tennessee
- Knoxville
- USA
| | - Tomonori Saito
- Chemical Sciences Division
- Oak Ridge National Laboratory
- Oak Ridge
- USA
| | | | - Robert L. Sacci
- Chemical Sciences Division
- Oak Ridge National Laboratory
- Oak Ridge
- USA
| | - Bobby G. Sumpter
- Center for Nanophase Materials Sciences
- Oak Ridge National Laboratory
- Oak Ridge
- USA
- Computational Sciences & Engineering Division
| | - Zaneta Wojnarowska
- Chemical Sciences Division
- Oak Ridge National Laboratory
- Oak Ridge
- USA
- Institute of Physics
| | - Vera Bocharova
- Chemical Sciences Division
- Oak Ridge National Laboratory
- Oak Ridge
- USA
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10
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Wu B, Kuroda K, Takahashi K, Castner EW. Structural analysis of zwitterionic liquids vs. homologous ionic liquids. J Chem Phys 2018; 148:193807. [PMID: 30307210 DOI: 10.1063/1.5010983] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Zwitterionic liquids (Zw-ILs) have been developed that are homologous to monovalent ionic liquids (ILs) and show great promise for controlled dissolution of cellulosic biomass. Using both high energy X-ray scattering and atomistic molecular simulations, this article compares the bulk liquid structural properties for novel Zw-ILs with their homologous ILs. It is shown that the significant localization of the charges on Zw-ILs leads to charge ordering similar to that observed for conventional ionic liquids with monovalent anions and cations. A low-intensity first sharp diffraction peak in the liquid structure factor S(q) is observed for both the Zw-IL and the IL. This is unexpected since both the Zw-IL and IL have a 2-(2-methoxyethoxy)ethyl (diether) functional group on the cationic imidazolium ring and ether functional groups are known to suppress this peak. Detailed analyses show that this intermediate range order in the liquid structure arises for slightly different reasons in the Zw-IL vs. the IL. For the Zw-IL, the ether tails in the liquid are shown to aggregate into nanoscale domains.
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Affiliation(s)
- Boning Wu
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, USA
| | - Kosuke Kuroda
- Institute of Science and Engineering, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
| | - Kenji Takahashi
- Institute of Science and Engineering, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
| | - Edward W Castner
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, USA
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11
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Lo Celso F, Triolo A, Gontrani L, Russina O. Communication: Anion-specific response of mesoscopic organization in ionic liquids upon pressurization. J Chem Phys 2018; 148:211102. [DOI: 10.1063/1.5036588] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Fabrizio Lo Celso
- Dipartimento di Fisica e Chimica, Università di Palermo, Palermo, Italy
- Laboratorio Liquidi Ionici, Istituto Struttura della Materia, CNR (ISM-CNR), Rome, Italy
| | - Alessandro Triolo
- Laboratorio Liquidi Ionici, Istituto Struttura della Materia, CNR (ISM-CNR), Rome, Italy
| | - Lorenzo Gontrani
- Dipartimento di Chimica, Sapienza University, P. le Aldo Moro 5, Roma, Italy
| | - Olga Russina
- Dipartimento di Chimica, Sapienza University, P. le Aldo Moro 5, Roma, Italy
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12
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Kapoor U, Shah JK. Effect of molecular solvents of varying polarity on the self-assembly of 1-n-dodecyl-3-methylimidazolium octylsulfate ionic liquid. JOURNAL OF THEORETICAL & COMPUTATIONAL CHEMISTRY 2018. [DOI: 10.1142/s0219633618400047] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Large-scale molecular dynamics simulations consisting of more than 88,000–106,000 atoms for approximately 250 ns (including equilibration and production) were conducted to assess the effect of polar, nonpolar and amphiphilic molecular solvents on the nanoscale structuring of 1-[Formula: see text]-dodecyl-3-methylimidazolium [C[Formula: see text]mim] octylsulfate [C8SO4] ionic liquid (IL). Water [H2O], [Formula: see text]-octane [C8H[Formula: see text]] and 1-octanol [C8H[Formula: see text]OH] are employed as examples of polar, nonpolar, and amphiphilic molecules, respectively. The results indicate that each of these molecular solvents modify the nanosegregation behavior of the ionic liquid in a unique way. Water induces a high order of structuring of the ionic liquid as indicated by extremely high nematic order parameter for the system. In addition, the morphology of the neat ionic liquid is transformed from layer-like to that of bilayer-like in which the polar and nonpolar domains alternate. The presence of water also causes the stretching of the nonpolar domain, thus, increasing its size. At the concentration examined in this work, [Formula: see text]-octane is found to be only partially miscible with the ionic liquid. The polar network is maintained; however, the continuous cationic nonpolar domain is split into multiple domains. [Formula: see text]-octane is accommodated in the ionic liquid nonpolar domain. Similarly, the amphiphilicity of 1-octanol leads to an increase in the number of cationic as well as anionic domains. The overall nonpolar domain length, however, remains nearly identical to that found for the pure ionic liquid. Additional characterization of structural features of the three systems is discussed in terms of one-dimensional number densities, nematic order parameters for the overall systems and their components and structure factors.
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Affiliation(s)
- Utkarsh Kapoor
- School of Chemical Engineering, Oklahoma State University, Stillwater, OK 74078, USA
| | - Jindal K. Shah
- School of Chemical Engineering, Oklahoma State University, Stillwater, OK 74078, USA
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