1
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Zhang N, Zhang Y, Liu Z, Liu Z, Sun C, Altun NE, Kou J. Investigation on Gold Dissolution Performance and Mechanism in Imidazolium Cyanate Ionic Liquids. Molecules 2024; 29:897. [PMID: 38398648 PMCID: PMC10891921 DOI: 10.3390/molecules29040897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Revised: 02/13/2024] [Accepted: 02/14/2024] [Indexed: 02/25/2024] Open
Abstract
To explore green gold leaching reagents, a series of imidazolium cyanate ionic liquids (ILs), 1-ethyl-3-methyl-imidazolium cyanate ([C2MIM][OCN]), 1-propyl-3-methyl-imidazolium cyanate ([C3MIM][OCN]) and 1-butyl-3-methyl-imidazolcyanate ([C4MIM][OCN]) were synthesized and characterized by Nuclear Magnetic Resonance (NMR), Fourier Transform Infrared Spectroscopy (FTIR) and thermogravimetric (TG) analysis. In this research, the imidazolium cyanates were utilized as a solute, which not only decreased the usage of ILs but also increased their gold dissolution capability. The gold dissolution performances of three imidazolium cyanates were characterized by dynamic leaching test and Scanning Electron Microscopy (SEM). The results show that the all three imidazolium cyanates had a gold dissolution ability, and the shorter the carbon chain on the imidazole ring in imidazolium cyanate, the faster the gold dissolution rate. The gold dissolution performance of [C2MIM][OCN] was the best, and the weight loss of gold leaf was 2.9 mg/cm2 at 40 °C after 120 h dissolution in [C2MIM][OCN] mixed with 10 wt. % water. Besides this, the gold dissolution rate increased with the increase in the concentration of imidazolium cyanates as well as the reaction temperature. The gold dissolution performances of imidazolium cyanates in different solvents including water, acetonitrile, dimethyl sulfoxide (DMSO) and dimethylformamide (DMF) were also investigated, and the weaker the polarity of the solvent, the more conducive it was to the gold dissolution reaction. The mechanism of gold dissolution by imidazolium cyanates was investigated through NMR spectroscopy and Electrospray Ionization Mass Spectrometry (ESI-MS). It was inferred that during the process of gold dissolution, Au was oxidized to Au+ and the imidazolium cations were deprotonated to form N-heterocyclic carbenes, which coordinated with gold to form gold complexes and achieve gold dissolution.
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Affiliation(s)
- Na Zhang
- School of Civil and Resource Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Yuxin Zhang
- School of Civil and Resource Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Zhengyu Liu
- School of Civil and Resource Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Ziyuan Liu
- School of Civil and Resource Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Chunbao Sun
- School of Civil and Resource Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - N. Emre Altun
- Department of Mining Engineering, Middle East Technical University, Ankara 06800, Türkiye
| | - Jue Kou
- School of Civil and Resource Engineering, University of Science and Technology Beijing, Beijing 100083, China
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Kim HJ. Spectroscopic and Chemical Properties of Ionic Liquids: Computational Study. CHEM REC 2023; 23:e202300075. [PMID: 37166396 DOI: 10.1002/tcr.202300075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 04/18/2023] [Indexed: 05/12/2023]
Abstract
A brief account is given of highlights of our computational efforts - often in collaboration with experimental groups - to understand spectroscopic and chemical properties of ionic liquids (ILs). Molecular dynamics, including their inhomogeneous character, responsible for key spectral features observed in dielectric absorption, infra-red (IR) and fluorescence correlation spectroscopy (FCS) measurements are elucidated. Mechanisms of chemical processes involving imidazolium-based ILs are illustrated for CO2 capture and related reactions, transesterification of cellulose, and Au nanocluster-catalyzed Suzuki cross-coupling reaction with attention paid to differing roles of IL ions. A comparison with experiments is also made.
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Affiliation(s)
- Hyung J Kim
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA 15213, USA
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3
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Fortunati A, Risplendi F, Re Fiorentin M, Cicero G, Parisi E, Castellino M, Simone E, Iliev B, Schubert TJS, Russo N, Hernández S. Understanding the role of imidazolium-based ionic liquids in the electrochemical CO 2 reduction reaction. Commun Chem 2023; 6:84. [PMID: 37120643 PMCID: PMC10148827 DOI: 10.1038/s42004-023-00875-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 04/06/2023] [Indexed: 05/01/2023] Open
Abstract
The development of efficient CO2 capture and utilization technologies driven by renewable energy sources is mandatory to reduce the impact of climate change. Herein, seven imidazolium-based ionic liquids (ILs) with different anions and cations were tested as catholytes for the CO2 electrocatalytic reduction to CO over Ag electrode. Relevant activity and stability, but different selectivities for CO2 reduction or the side H2 evolution were observed. Density functional theory results show that depending on the IL anions the CO2 is captured or converted. Acetate anions (being strong Lewis bases) enhance CO2 capture and H2 evolution, while fluorinated anions (being weaker Lewis bases) favour the CO2 electroreduction. Differently from the hydrolytically unstable 1-butyl-3-methylimidazolium tetrafluoroborate, 1-Butyl-3-Methylimidazolium Triflate was the most promising IL, showing the highest Faradaic efficiency to CO (>95%), and up to 8 h of stable operation at high current rates (-20 mA & -60 mA), which opens the way for a prospective process scale-up.
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Affiliation(s)
- Alessia Fortunati
- Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129, Turin, Italy
| | - Francesca Risplendi
- Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129, Turin, Italy.
| | - Michele Re Fiorentin
- Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129, Turin, Italy
| | - Giancarlo Cicero
- Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129, Turin, Italy
| | - Emmanuele Parisi
- Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129, Turin, Italy
| | - Micaela Castellino
- Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129, Turin, Italy
| | - Elena Simone
- Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129, Turin, Italy
| | - Boyan Iliev
- Iolitec Ionic Liquids Technologies GmbH, Im Zukunftspark 9, 74076, Heilbronn, Germany
| | - Thomas J S Schubert
- Iolitec Ionic Liquids Technologies GmbH, Im Zukunftspark 9, 74076, Heilbronn, Germany
| | - Nunzio Russo
- Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129, Turin, Italy
| | - Simelys Hernández
- Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129, Turin, Italy.
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Liebertseder M, Donsbach C, Feldmann C. Reactions of noble-metal oxides in ionic liquids near room temperature. RSC Adv 2023; 13:11441-11449. [PMID: 37057275 PMCID: PMC10089254 DOI: 10.1039/d3ra00892d] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Accepted: 03/14/2023] [Indexed: 04/15/2023] Open
Abstract
The reaction of Ag2O, Au2O3, and HgO with CuCl, CuI, AgCl, AgI, AuCl, and AuI in ionic liquids ([EMIm]Cl, [BMIm]Cl) near room temperature (20-80 °C) is evaluated and results in the new compounds (C8H14N2)CuCl, (C8H14N2)AgI, (C6H10N2)AuCl, [(C8H14N2)2Hg][CuCl3], [(C8H14N2)2Hg][AgCl3], and [EMIm][Ag2I2Cl]. Thereof, (C8H14N2)CuCl, (C8H14N2)AgI, (C6H10N2)AuCl, [(C8H14N2)2Hg][CuCl3], and [(C8H14N2)2Hg][AgCl3] are NHC complexes (NHC: N-heterocyclic carbene) with M-C bonds (M: Cu, Ag, Au, Hg). Whereas (C8H14N2)CuCl and (C8H14N2)AgI crystallize as single molecules, (C6H10N2)AuCl is dimerized via aurophilic interactions. [(C8H14N2)2Hg][CuCl3] and [(C8H14N2)2Hg][AgCl3] exhibit Hg atoms with two Hg-C bonds. Moreover, (C8H14N2)AgI shows intense green fluorescence at room temperature with a quantum yield of 44%, whereas all other compounds do not show any emission at room temperature. Finally, [EMIm][Ag2I2Cl] is not an NHC compound but contains ∞ 1[AgI1/2I2/4Cl1/2]- chains with infinite d10-d10 interaction of the silver atoms. The title compounds are characterized by single-crystal structure analysis, infrared spectroscopy, thermogravimetry, and fluorescence spectroscopy.
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Affiliation(s)
- Mareike Liebertseder
- Institute for Inorganic Chemistry, Karlsruhe Institute of Technology (KIT) Engesserstrasse 15 D-76131 Karlsruhe Germany
| | - Carsten Donsbach
- Institute for Inorganic Chemistry, Karlsruhe Institute of Technology (KIT) Engesserstrasse 15 D-76131 Karlsruhe Germany
| | - Claus Feldmann
- Institute for Inorganic Chemistry, Karlsruhe Institute of Technology (KIT) Engesserstrasse 15 D-76131 Karlsruhe Germany
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Shah S, Pietsch T, Ruck M. N-heterocyclic carbene-mediated oxidation of copper(I) in an imidazolium ionic liquid. ZEITSCHRIFT FUR NATURFORSCHUNG SECTION B-A JOURNAL OF CHEMICAL SCIENCES 2023. [DOI: 10.1515/znb-2022-0305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/11/2023]
Abstract
Abstract
The aerobic oxidation of copper(I) to copper(II) was studied in the ionic liquid (IL) 1-n-butyl-3-methylimidazolium acetate [BMIm][OAc]. Temperatures above 100 °C promote the deprotonation of the C2 atom of the imidazolium ring and the dissolution of CuCl. 1H and 13C NMR spectra indicate the formation of the N-heterocyclic carbene (NHC) complex [NHC] CuICl under inert conditions. Upon aerobic oxidation, air-stable blue-green crystals of [BMIm]2[CuII
2(OAc)4Cl2] precipitate in high yield and the NHC is recovered. X-ray diffraction on a single-crystal of the complex salt revealed a monoclinic structure with space group P21/n. The centrosymmetric dinuclear acetate complex [Cu2(OAc)4Cl2]2– has the paddle-wheel motif and is weakly paramagnetic.
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Affiliation(s)
- Sameera Shah
- Fakultät Chemie und Lebensmittelchemie , Technische Universität Dresden , 01062 Dresden , Germany
- Max-Planck-Institut für Chemische Physik fester Stoffe , Nöthnitzer Straße 40, 01187 Dresden , Germany
| | - Tobias Pietsch
- Fakultät Chemie und Lebensmittelchemie , Technische Universität Dresden , 01062 Dresden , Germany
- Max-Planck-Institut für Chemische Physik fester Stoffe , Nöthnitzer Straße 40, 01187 Dresden , Germany
| | - Michael Ruck
- Fakultät Chemie und Lebensmittelchemie , Technische Universität Dresden , 01062 Dresden , Germany
- Max-Planck-Institut für Chemische Physik fester Stoffe , Nöthnitzer Straße 40, 01187 Dresden , Germany
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6
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Sazanova TS, Akhmetshina AI, Petukhov AN, Vorotyntsev AV, Suvorov SS, Barysheva AV, Mechergui A, Nyuchev AV, Kazarina OV, Stepakova AN, Atlaskina ME, Atlaskin AA, Kryuchkov SS, Vorotyntsev IV. The Cation Effect on the Free Volume and the Solubility of H 2S and CO 2 in Ionic Liquids Based on Bis(2-Ethylhexyl) Sulfosuccinate Anion. MEMBRANES 2023; 13:238. [PMID: 36837741 PMCID: PMC9965390 DOI: 10.3390/membranes13020238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Revised: 02/12/2023] [Accepted: 02/13/2023] [Indexed: 06/18/2023]
Abstract
Herein, we report for the first time a study dedicated to acidic gases' solubility in ionic liquids with sterically hindered bulky anion, namely bis(2-ethylhexyl) sulfosuccinate ([doc]), experimentally evaluated at low pressures. The effect of cation change (imidazolium, pyridinium, and pyrrolidinium) on the thermophysical properties and sorption capacities was also discussed. The densities and the activation energies of the tested ILs exhibited minor differences. Furthermore, the COSMO-RS model was used to predict the free volumes of ILs aiming to investigate its influence on gas solubilities. The conducted calculations have revealed an antibate correlation between the fractional free volume (FFV) and Henry's law constant. In particular, the lowest FFV in 1-methylimidazolium [doc] corresponded to the minimal sorption and vice versa. In addition, it was shown that the presence of protic cation results in a significant reduction in CO2 and H2S solubilities. In general, the solubility measurement results of the synthesized ILs have shown their superiority compared to fluorinated ILs based on the physical absorption mechanism.
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Affiliation(s)
- Tatyana S. Sazanova
- Laboratory of SMART Polymeric Materials and Technologies, Mendeleev University of Chemical Technology, 9 Miusskaya Sq., 125047 Moscow, Russia
| | - Alsu I. Akhmetshina
- Department of Technologies for the Processing of Polymers and Composite Materials, Kazan National Research Technological University, 68 Karl Marx Str., 420015 Kazan, Russia
| | - Anton N. Petukhov
- Laboratory of SMART Polymeric Materials and Technologies, Mendeleev University of Chemical Technology, 9 Miusskaya Sq., 125047 Moscow, Russia
- Chemical Engineering Laboratory, Research Institute for Chemistry, N.I. Lobachevsky State University of Nizhny Novgorod, 23 Gagarin Avenue, 603950 Nizhny Novgorod, Russia
| | - Andrey V. Vorotyntsev
- Chemical Engineering Laboratory, Research Institute for Chemistry, N.I. Lobachevsky State University of Nizhny Novgorod, 23 Gagarin Avenue, 603950 Nizhny Novgorod, Russia
| | - Sergey S. Suvorov
- Chemical Engineering Laboratory, Research Institute for Chemistry, N.I. Lobachevsky State University of Nizhny Novgorod, 23 Gagarin Avenue, 603950 Nizhny Novgorod, Russia
| | - Alexandra V. Barysheva
- Chemical Engineering Laboratory, Research Institute for Chemistry, N.I. Lobachevsky State University of Nizhny Novgorod, 23 Gagarin Avenue, 603950 Nizhny Novgorod, Russia
| | - Amal Mechergui
- Laboratory of SMART Polymeric Materials and Technologies, Mendeleev University of Chemical Technology, 9 Miusskaya Sq., 125047 Moscow, Russia
| | - Alexander V. Nyuchev
- Chemical Engineering Laboratory, Research Institute for Chemistry, N.I. Lobachevsky State University of Nizhny Novgorod, 23 Gagarin Avenue, 603950 Nizhny Novgorod, Russia
| | - Olga V. Kazarina
- Laboratory of SMART Polymeric Materials and Technologies, Mendeleev University of Chemical Technology, 9 Miusskaya Sq., 125047 Moscow, Russia
- Chemical Engineering Laboratory, Research Institute for Chemistry, N.I. Lobachevsky State University of Nizhny Novgorod, 23 Gagarin Avenue, 603950 Nizhny Novgorod, Russia
| | - Anna N. Stepakova
- Laboratory of SMART Polymeric Materials and Technologies, Mendeleev University of Chemical Technology, 9 Miusskaya Sq., 125047 Moscow, Russia
| | - Maria E. Atlaskina
- Laboratory of SMART Polymeric Materials and Technologies, Mendeleev University of Chemical Technology, 9 Miusskaya Sq., 125047 Moscow, Russia
| | - Artem A. Atlaskin
- Laboratory of SMART Polymeric Materials and Technologies, Mendeleev University of Chemical Technology, 9 Miusskaya Sq., 125047 Moscow, Russia
| | - Sergey S. Kryuchkov
- Laboratory of SMART Polymeric Materials and Technologies, Mendeleev University of Chemical Technology, 9 Miusskaya Sq., 125047 Moscow, Russia
| | - Ilya V. Vorotyntsev
- Laboratory of SMART Polymeric Materials and Technologies, Mendeleev University of Chemical Technology, 9 Miusskaya Sq., 125047 Moscow, Russia
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7
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Belesov AV, Anikeenko EA, Faleva AV, Ul’yanovskii NV, Kosyakov DS. Study of Nitrogen-Containing Products of the Interaction of 1-Butyl-3-Methylimidazolium Cation with Lignin by MALDI Mass Spectrometry. JOURNAL OF ANALYTICAL CHEMISTRY 2022. [DOI: 10.1134/s1061934822360011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
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8
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Salvitti C, Pepi F, Managò M, Bortolami M, Michenzi C, Chiarotto I, Troiani A, de Petris G. Free N-heterocyclic carbenes from Brønsted acidic ionic liquids: Direct detection by electrospray ionization mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2022; 36:e9338. [PMID: 35729083 PMCID: PMC9542177 DOI: 10.1002/rcm.9338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Revised: 06/17/2022] [Accepted: 06/17/2022] [Indexed: 06/15/2023]
Abstract
RATIONALE The occurrence of N-heterocyclic carbenes in imidazolium-based ionic liquids has long been discussed, but no spectroscopic evidence has been reported yet due to their transient nature. The insertion of an ionizable acid group into the cation scaffold of an ionic liquid which acts as a charge tag allows for the direct detection of free carbenes by mass spectrometry. METHODS Three different Brønsted acidic ionic liquids were synthesized: 1-methyl-3-carboxymethylimidazolium chloride (MAICl), 1-methyl-3-carboxymethylimidazolium acetate (MAIAc) and the corresponding 2-(3-methyl-1H-imidazol-3-ium-1-yl)acetate zwitterion (MAI - H). The speciation of these compounds was then analysed by electrospray ionization ion-trap mass spectrometry in the negative ion mode. RESULTS The C2-H deprotonation of the imidazolium cation leading to the formation of the corresponding carbene is highly affected by the basic properties of the counter-anion. In the case of MAICl and MAI - H ionic liquids, no charged species corresponding to the free N-heterocyclic carbene was detected. On the contrary, in the presence of a sufficiently basic anion, such as acetate of MAIAc ionic liquid, an intense signal related to the free carbenic species was observed without the addition of an external base. CONCLUSIONS In situ formation of free N-heterocyclic carbenes from Brønsted acidic ionic liquids was demonstrated, highlighting the crucial role of anion basicity in promoting the C2-H proton abstraction from imidazolium cations with a carboxylic side chain.
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Affiliation(s)
- Chiara Salvitti
- Dipartimento di Chimica e Tecnologie del FarmacoSapienza Università di RomaRomeItaly
| | - Federico Pepi
- Dipartimento di Chimica e Tecnologie del FarmacoSapienza Università di RomaRomeItaly
| | - Marta Managò
- Dipartimento di Chimica e Tecnologie del FarmacoSapienza Università di RomaRomeItaly
| | - Martina Bortolami
- Dipartimento di Scienze di Base e Applicate per l'IngegneriaSapienza Università di RomaRomeItaly
| | - Cinzia Michenzi
- Dipartimento di Scienze di Base e Applicate per l'IngegneriaSapienza Università di RomaRomeItaly
| | - Isabella Chiarotto
- Dipartimento di Scienze di Base e Applicate per l'IngegneriaSapienza Università di RomaRomeItaly
| | - Anna Troiani
- Dipartimento di Chimica e Tecnologie del FarmacoSapienza Università di RomaRomeItaly
| | - Giulia de Petris
- Dipartimento di Chimica e Tecnologie del FarmacoSapienza Università di RomaRomeItaly
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9
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Grasser MA, Müller U, Ruck M. Low‐Temperature Synthesis of NiSb2, Cu2Sb, InSb and Sb2Te3 Starting from the Elements. Z Anorg Allg Chem 2022. [DOI: 10.1002/zaac.202200195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | - Michael Ruck
- Technische Universität Dresden Faculty of Chemistry and Food Chemistry Helmholtzstr. 10 01069 Dresden GERMANY
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10
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Structural effect of imidazolium salts on electrochemical conversion of carbon dioxide to imidazolium carboxylate. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.118964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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11
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Stoppelman JP, McDaniel JG. Physics-based, neural network force fields for reactive molecular dynamics: Investigation of carbene formation from [EMIM +][OAc -]. J Chem Phys 2021; 155:104112. [PMID: 34525833 DOI: 10.1063/5.0063187] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Reactive molecular dynamics simulations enable a detailed understanding of solvent effects on chemical reaction mechanisms and reaction rates. While classical molecular dynamics using reactive force fields allows significantly longer simulation time scales and larger system sizes compared with ab initio molecular dynamics, constructing reactive force fields is a difficult and complex task. In this work, we describe a general approach following the empirical valence bond framework for constructing ab initio reactive force fields for condensed phase simulations by combining physics-based methods with neural networks (PB/NNs). The physics-based terms ensure the correct asymptotic behavior of electrostatic, polarization, and dispersion interactions and are compatible with existing solvent force fields. NNs are utilized for a versatile description of short-range orbital interactions within the transition state region and accurate rendering of vibrational motion of the reacting complex. We demonstrate our methodology for a simple deprotonation reaction of the 1-ethyl-3-methylimidazolium cation with acetate to form 1-ethyl-3-methylimidazol-2-ylidene and acetic acid. Our PB/NN force field exhibits ∼1 kJ mol-1 mean absolute error accuracy within the transition state region for the gas-phase complex. To characterize the solvent modulation of the reaction profile, we compute potentials of mean force for the gas-phase reaction as well as the reaction within a four-ion cluster and benchmark against ab initio molecular dynamics simulations. We find that the surrounding ionic environment significantly destabilizes the formation of the carbene product, and we show that this effect is accurately captured by the reactive force field. By construction, the PB/NN potential may be directly employed for simulations of other solvents/chemical environments without additional parameterization.
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Affiliation(s)
- John P Stoppelman
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, USA
| | - Jesse G McDaniel
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, USA
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12
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Belesov AV, Ladesov AV, Pokryshkin SA, Kosyakov DS. Study of the Composition of Volatile By-Products, Formed by Dissolution of Wood in Ionic Liquids Based on 1-Butyl-3-Methylimidazolium. RUSS J APPL CHEM+ 2021. [DOI: 10.1134/s1070427221030101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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13
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Salvitti C, Bortolami M, Chiarotto I, Troiani A, de Petris G. The Knoevenagel condensation catalysed by ionic liquids: a mass spectrometric insight into the reaction mechanism. NEW J CHEM 2021. [DOI: 10.1039/d1nj03594k] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Mass spectrometry was used to study the Knoevenagel condensation catalysed by imidazolium-based ionic liquids. Two pathways were highlighted by intercepting two different reaction intermediates: a base-catalysed and a carbene-catalysed mechanism.
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Affiliation(s)
- Chiara Salvitti
- Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza Università di Roma, P.le Aldo Moro 5, 00185 Roma, Italy
| | - Martina Bortolami
- Dipartimento di Scienze di Base e Applicate per l’Ingegneria, Sapienza Università di Roma, Via Castro Laurenziano 7, Roma, Italy
| | - Isabella Chiarotto
- Dipartimento di Scienze di Base e Applicate per l’Ingegneria, Sapienza Università di Roma, Via Castro Laurenziano 7, Roma, Italy
| | - Anna Troiani
- Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza Università di Roma, P.le Aldo Moro 5, 00185 Roma, Italy
| | - Giulia de Petris
- Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza Università di Roma, P.le Aldo Moro 5, 00185 Roma, Italy
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14
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Zhou Y, Liu W, Liu Y, Guan J, Yan J, Yuan JJ, Tao DJ, Song Z. Oxidative NHC catalysis for base-free synthesis of benzoxazinones and benzoazoles by thermal activated NHCs precursor ionic liquid catalyst using air as oxidant. MOLECULAR CATALYSIS 2020. [DOI: 10.1016/j.mcat.2020.111013] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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15
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Characterization of Ionic Liquid Lignins Isolated from Spruce Wood with 1-Butyl-3-methylimidazolium Acetate and Methyl Sulfate and Their Binary Mixtures with DMSO. Molecules 2020; 25:molecules25112479. [PMID: 32471064 PMCID: PMC7321317 DOI: 10.3390/molecules25112479] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 05/23/2020] [Accepted: 05/25/2020] [Indexed: 11/17/2022] Open
Abstract
Ionic liquids (ILs) based on 1-butyl-3-methylimidazolium (bmim) cation have proved to be promising solvents for the fractionation of plant biomass with the production of cellulose and lignin. This study deals with the characterization of lignins isolated from coniferous (spruce) wood using [bmim]OAc and [bmim]MeSO4 ionic liquids and their binary mixtures with DMSO (80:20). Molecular weight distributions, functional composition, and structural features of IL lignins were studied by size-exclusion chromatography, NMR spectroscopy (1D and 2D) and atmospheric pressure photoionization high-resolution mass spectrometry. It was shown that the interaction of ILs with lignin leads to significant chemical changes in the biopolymer; a decrease in the degree of polymerization and in the content of free phenolic hydroxyl groups due to alkylation, the disappearance (in the case of [bmim]OAc) of carbonyl groups and a significant destruction of β-O-4 bonds. The chemical reactions between lignin and 1-butyl-3-methylidazolium cation with covalent binding of ionic liquids or products of their decomposition is evidenced by the presence of a large number of nitrogen-containing oligomers in IL lignins.
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Jain P, Chaudhari VR, Kumar A. Water-assisted stability of carbene: cyclic voltammetric investigation of 1-ethyl-3-methylimidazolium ethylsulfate ionic liquid. Phys Chem Chem Phys 2019; 21:24126-24131. [PMID: 31657400 DOI: 10.1039/c9cp05033g] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
In this work, we report electrochemical studies on imidazolium-based ionic liquids with an objective to explore the possibility of carbene formation in their dilute aqueous solutions. Conventionally, water plays a detrimental role during investigations involving ionic liquids, and this role has been investigated via electrochemical studies in aqueous ionic liquid solutions. There are varying opinions regarding the influence of water on the physicochemical behaviour of ionic liquids that require an in-depth understanding. To eludicate the role of water, we attempted to evaluate the electrochemical performance of ionic liquids in water as a solvent, and the influence of water on ionic liquids was explored through feasibility and stability studies on carbene formed in an aqueous imidazolium-based ionic liquid solution. The electrochemical investigation of an aqueous solution of 1-ethyl-3-methylimidazolium ethylsulfate ([EMIM][EtSO4]) revealed a redox couple. Detailed investigations suggest that reduction of the imidazolium cation occurs at the C2 position, with subsequent formation of carbene. Furthermore, an anodic peak was found to be associated with the oxidation of carbene. The coulometric process associated with the anodic peaks indicated that the two-electron oxidation of carbene occurred. The stability of carbene in water was evaluated through the use of different protic and aprotic solvents. The hydrogen bond-forming ability of carbene with water seems to be responsible for its improved stability in water.
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Affiliation(s)
- Preeti Jain
- Physical & Material Chemistry Division, CSIR-National Chemical Laboratory, Dr Homi Bhabha Road, Pune 411008, India.
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17
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Gehrke S, Reckien W, Palazzo I, Welton T, Hollóczki O. On the Carbene-Like Reactions of Imidazolium Acetate Ionic Liquids: Can Theory and Experiments Agree? European J Org Chem 2018. [DOI: 10.1002/ejoc.201801050] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Sascha Gehrke
- Mulliken Center for Theoretical Chemistry; University of Bonn; Beringstr. 4+6 Bonn Germany
- Max Planck Institute for Chemical Energy Conversion; Stiftstrasse 34-36 45470 Muelheim an der Ruhr Germany
| | - Werner Reckien
- Mulliken Center for Theoretical Chemistry; University of Bonn; Beringstr. 4+6 Bonn Germany
| | - Ivan Palazzo
- Department of Chemistry; Imperial College London; 2AZ London, SW7 UK
| | - Tom Welton
- Department of Chemistry; Imperial College London; 2AZ London, SW7 UK
| | - Oldamur Hollóczki
- Mulliken Center for Theoretical Chemistry; University of Bonn; Beringstr. 4+6 Bonn Germany
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18
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Chiarotto I, Mattiello L, Pandolfi F, Rocco D, Feroci M. NHC in Imidazolium Acetate Ionic Liquids: Actual or Potential Presence? Front Chem 2018; 6:355. [PMID: 30211149 PMCID: PMC6121013 DOI: 10.3389/fchem.2018.00355] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 07/30/2018] [Indexed: 11/13/2022] Open
Abstract
Ionic liquids (ILs) are considered in the majority of cases green solvents, due to their virtually null vapor pressure and to the easiness in recycling them. In particular, imidazolium ILs are widely used in many fields of Chemistry, as solvents or precursors of N-heterocyclic carbenes (NHCs). The latter are easily obtained by deprotonation of the C2-H, usually using strong bases or cathodic reduction. Nevertheless, it is known that weaker bases (e.g., triethylamine) are able to promote C2-H/D exchange. From this perspective, the possibility of deprotonating C2-H group of an imidazolium cation by means of a basic counter-ion was seriously considered and led to the synthesis of imidazolium ILs spontaneously containing NHCs. The most famous of this class of ILs are N,N'-disubstituted imidazolium acetates. Due to the particular reactivity of this kind of ILs, they were appointed as “organocatalytic ionic liquids” or “proto-carbenes.” Many papers report the use of these imidazolium acetates in organocatalytic reactions (i. e., catalyzed by NHC) or in stoichiometric NHC reactions (e.g., with elemental sulfur to yield the corresponding imidazole-2-thiones). Nevertheless, the actual presence of NHC in N,N'-disubstituted imidazolium acetate is still controversial. Moreover, theoretical studies seem to rule out the presence of NHC in such a polar environment as an IL. Aim of this Mini Review is to give the reader an up-to-date overview on the actual or potential presence of NHC in such an “organocatalytic ionic liquid,” both from the experimental and theoretical point of view, without the intent to be exhaustive on N,N'-disubstituted imidazolium acetate applications.
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Affiliation(s)
- Isabella Chiarotto
- Dipartimento di Scienze di Base e Applicate per l'Ingegneria, Sapienza University of Rome, Rome, Italy
| | - Leonardo Mattiello
- Dipartimento di Scienze di Base e Applicate per l'Ingegneria, Sapienza University of Rome, Rome, Italy
| | - Fabiana Pandolfi
- Dipartimento di Scienze di Base e Applicate per l'Ingegneria, Sapienza University of Rome, Rome, Italy
| | - Daniele Rocco
- Dipartimento di Scienze di Base e Applicate per l'Ingegneria, Sapienza University of Rome, Rome, Italy
| | - Marta Feroci
- Dipartimento di Scienze di Base e Applicate per l'Ingegneria, Sapienza University of Rome, Rome, Italy
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19
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Yan F, Kakuchi R, Takahashi K, Kim HJ. CS 2 capture in the ionic liquid 1-alkyl-3-methylimidazolium acetate: reaction mechanism and free energetics. Phys Chem Chem Phys 2018; 20:19339-19349. [PMID: 29989138 DOI: 10.1039/c8cp01724g] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Reaction pathways for CS2 and COS in the ionic liquid, 1-ethyl-3-methylimidazolium (EMI+) acetate (OAc-), are studied using the ab initio self-consistent reaction field theory (SCRF) and molecular dynamics (MD) computer simulations. It is found that while CS2 converts to COS nearly at the 100% level through S/O exchange with acetate, both conversion and capture processes are kinetically possible for COS, yielding CO2/thioacetate and 1-ethyl-3-methylimidazole-2-thiocarboxylate (EMI-COS)/acetic acid as reaction products, respectively. These findings are in excellent agreement with recent experimental observations in the closely related 1-butyl-3-methylimidazolium acetate (BMI+OAc-) ionic liquid system. Constrained ab initio MD indicates that the capture reaction of COS (and CS2 if allowed) proceeds in a concerted fashion; viz., proton transfer from EMI+ to OAc- and carboxylation of EMI+ by COS (and CS2) occur concurrently, analogous to the concerted pathway proposed recently for CO2 capture in the imidazolium acetate ionic liquid family. As N-heterocyclic carbene (NHC) is not required, the concerted mechanism is fully consistent with the experimental fact that NHC has not been detected directly in this ionic liquid family. Computational analysis further predicts that if NHC would be present in the ionic liquid, it would react with CS2 and produce 1-ethyl-3-imidazole-2-dithiocarboxylate, prior to the conversion of CS2 to COS. Since such a dithiocarboxylate compound was not detected experimentally, the present analysis lends support to the view that NHC is not formed in the pure imidazolium acetate ionic liquid family.
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Affiliation(s)
- Fangyong Yan
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
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20
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Pandolfi F, Feroci M, Chiarotto I. Role of Anion and Cation in the 1-Methyl-3-butyl Imidazolium Ionic Liquids BMImX: The Knoevenagel Condensation. ChemistrySelect 2018. [DOI: 10.1002/slct.201800295] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Fabiana Pandolfi
- Department Dipartimento di Scienze di Base e Applicate per l'Ingegneria; Sapienza Università di Roma; Via del Castro Laurenziano 7- 00161 Roma Italy
| | - Marta Feroci
- Department Dipartimento di Scienze di Base e Applicate per l'Ingegneria; Sapienza Università di Roma; Via del Castro Laurenziano 7- 00161 Roma Italy
| | - Isabella Chiarotto
- Department Dipartimento di Scienze di Base e Applicate per l'Ingegneria; Sapienza Università di Roma; Via del Castro Laurenziano 7- 00161 Roma Italy
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21
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Patrick AL, Vogelhuber KM, Prince BD, Annesley CJ. Theoretical and Experimental Insights into the Dissociation of 2-Hydroxyethylhydrazinium Nitrate Clusters Formed via Electrospray. J Phys Chem A 2018; 122:1960-1966. [PMID: 29382196 DOI: 10.1021/acs.jpca.7b12072] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Ionic liquids are used for myriad applications, including as catalysts, solvents, and propellants. Specifically, 2-hydroxyethylhydrazinium nitrate (HEHN) has been developed as a chemical propellant for space applications. The gas-phase behavior of HEHN ions and clusters is important in understanding its potential as an electrospray thruster propellant. Here, the unimolecular dissociation pathways of two clusters are experimentally observed, and theoretical modeling of hydrogen bonding and dissociation pathways is used to help rationalize those observations. The cation/deprotonated cation cluster [HEH2 - H]+, which is observed from electrospray ionization, is calculated to be considerably more stable than the complementary cation/protonated anion adduct, [HEH + HNO3]+, which is not observed experimentally. Upon collisional activation, a larger cluster [(HEHN)2HEH]+ undergoes dissociation via loss of nitric acid at lower collision energies, as predicted theoretically. At higher collision energies, additional primary and secondary loss pathways open, including deprotonated cation loss, ion-pair loss, and double-nitric-acid loss. Taken together, these experimental and theoretical results contribute to a foundational understanding of the dissociation of protic ionic liquid clusters in the gas phase.
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Affiliation(s)
- Amanda L Patrick
- Space Vehicles Directorate, Air Force Research Laboratory, Kirtland Air Force Base , New Mexico 87117, United States
| | - Kristen M Vogelhuber
- Space Vehicles Directorate, Air Force Research Laboratory, Kirtland Air Force Base , New Mexico 87117, United States.,Institute for Scientific Research, Boston College , Chestnut Hill, Massachusetts 02467, United States
| | - Benjamin D Prince
- Space Vehicles Directorate, Air Force Research Laboratory, Kirtland Air Force Base , New Mexico 87117, United States
| | - Christopher J Annesley
- Space Vehicles Directorate, Air Force Research Laboratory, Kirtland Air Force Base , New Mexico 87117, United States
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Daud NMAN, Bakis E, Hallett JP, Weber CC, Welton T. Evidence for the spontaneous formation of N-heterocyclic carbenes in imidazolium based ionic liquids. Chem Commun (Camb) 2017; 53:11154-11156. [PMID: 28890962 DOI: 10.1039/c7cc06112a] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
We present a study of the reactions of aldehydes in ionic liquids which gives evidence for the spontaneous formation of N-heterocyclic carbenes in ionic liquids based on 1,3-dialkyl substituted imidazolium cations from the lack of a deuterium isotope effect on the reaction of these ionic liquids with aldehydes.
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Affiliation(s)
- N M A N Daud
- Department of Chemistry, Imperial College London, London, SW7 2AZ, UK.
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