scholarly journals The Influence of the Nature of Redox-Active Moieties on the Properties of Redox-Active Ionic Liquids and on Their Use as Electrolyte for Supercapacitors

Energies ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 6344
Author(s):  
Philipp S. Borchers ◽  
Patrick Gerlach ◽  
Yihan Liu ◽  
Martin D. Hager ◽  
Andrea Balducci ◽  
...  
Keyword(s):  
Phase Transition ◽  
Differential Scanning Calorimetry ◽  
Ionic Liquid ◽  
Ionic Liquids ◽  
Binary Mixtures ◽  
Thermal Characteristics ◽  
The Other ◽  
Scanning Calorimetry ◽  
Imidazolium Ionic Liquids ◽  
Redox Active

In this work, two new redox-active ionic liquids, one based on 2,2,6,6-tetramethylpiperidine-N-oxide and the other based on 4,4′-bipyridine, are synthesized and characterized. A ferrocene-based redox-active ionic liquid is used for referencing the results. All ionic liquids are formed via salt-metathesis from halogenate to bis(trifluoromethylsulfonyl)imide. Their fundamental thermal characteristics are assessed with differential scanning calorimetry. While the imidazolium ionic liquids show no melting point, the phase transition is well observable for the viologen-based ionic liquid. The properties of the neat redox-active ionic liquids and of binary mixtures containing these ionic liquids (0.1 m) and 1-butyl-1-methyl pyrrolidinium-bis(trifluoromethylsulfonyl)imide have been investigated. Finally, the use of these binary mixtures in combination with activated carbon-based electrodes has been considered in view of the use of these redox-active electrolytes in supercapacitors.

Amorphous iron oxide prepared by microwave heating

2000 ◽  
Vol 15 (10) ◽  
pp. 2176-2181 ◽  
Author(s):  
Oleg Palchik ◽  
Israel Felner ◽  
Gina Kataby ◽  
Aharon Gedanken
Keyword(s):  
Phase Transition ◽  
Differential Scanning Calorimetry ◽  
Iron Oxide ◽  
Iron Pentacarbonyl ◽  
Microwave Oven ◽  
The Other ◽  
Scanning Calorimetry ◽  
Amorphous Iron ◽  
Domestic Microwave Oven ◽  
Crystalline Phase Transition

Amorphous iron oxide (Fe2O3) was prepared by the pyrolysis of iron pentacarbonyl [Fe(CO)5] in a modified domestic microwave oven in refluxing chlorobenzene as a solvent under air. The reaction time was 20 min. Partially separated particles of iron oxide, 2–3 nm in diameter, were obtained. The other part showed aggregated spheres with a diameter of 25–40 nm. Differential scanning calorimetry measurements showed an amorphous/crystalline phase transition at about 250 °C.

scholarly journals Synthesis and Characterization of a Novel Hydroquinone Sulfonate-Based Redox Active Ionic Liquid

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3259
Author(s):  
Farida H. Aidoudi ◽  
Alessandro Sinopoli ◽  
Muthumeenal Arunachalam ◽  
Belabbes Merzougui ◽  
Brahim Aïssa
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
High Stability ◽  
Supporting Electrolyte ◽  
Ionic Species ◽  
Scanning Calorimetry ◽  
Energy Applications ◽  
Redox Active ◽  
Step Procedure ◽  
Different Temperatures

Introducing redox-active moieties into an ionic liquid (IL) structure is an exciting and attractive approach that has received increasing interest over recent years for a various range of energy applications. The so-called redox-active ionic liquids (RAILs) provide a highly versatile platform to potentially create multifunctional electroactive materials. Ionic liquids are molten salts consisting of ionic species, often having a melting point lower than 100 °C. Such liquids are obtained by combining a bulky asymmetric organic cation and a small anion. Here, we report on the synthesis of a novel RAIL, namely 1-butyl-3-methylimidazolium hydroquinone sulfonate ((BMIM)(HQS)). (BMIM)(HQS) was synthesized in a two-step procedure, starting by the quaternization of methylimidazole using butylchloride to produce 1-butyl-3-methylimidazolium chloride ((BMIM)(Cl)), and followed by the anion exchange reaction, where the chloride anion is exchanged with hydroquinone sulfonate. The resulting product was characterized by 1H NMR, 13C NMR, FT-IR spectroscopy, themogravimetric analysis, and differential scanning calorimetry, and shows a high stability up to 340 °C. Its electrochemical behavior was investigated using cyclic voltammetry at different temperatures and its viscosity analysis was also performed at variable temperatures. The electrochemical response of the presented RAIL was found to be temperature dependent and diffusion controlled. Overall, our results demonstrated that (BMIM)(HQS) is redox active and possesses high stability and low volatility, leading to the employment of this RAIL without any additional supporting electrolyte or additives.

Solid–liquid equilibria in systems [Cxmim][Tf2N] with diethylamine

2015 ◽  
Vol 87 (5) ◽  
pp. 453-460 ◽  
Author(s):  
Jan Rotrekl ◽  
Pavel Vrbka ◽  
Zuzana Sedláková ◽  
Zdeněk Wagner ◽  
Johan Jacquemin ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Ionic Liquid ◽  
Ionic Liquids ◽  
Phase Equilibrium ◽  
Binary System ◽  
Activity Coefficients ◽  
Liquid Equilibrium ◽  
Scanning Calorimetry ◽  
Solid Liquid ◽  
System 1

AbstractIn the present work, the solid–liquid–liquid equilibrium in the binary system of diethylamine (1) and ionic liquid (2) 1-methyl-3-ethylimidazolium bis(trifluoromethylsulfonyl)imide and solid–liquid equilibrium in system 1-methyl-3-butylimidazolium bis(trifluoromethylsulfonyl)imide was studied. Phase equilibrium was determined experimentally by means of a polythermic method. These data were then used to determine the activity coefficients for both ionic liquids. For the pure diethylamine the enthalpy of fusion was determined by differential scanning calorimetry, because to the best of our knowledge, this data is not yet reported in the open literature, a contrario of pure ionic liquids tested during this work.

scholarly journals Thermal Analysis of Binary Mixtures of Imidazolium, Pyridinium, Pyrrolidinium, and Piperidinium Ionic Liquids

Molecules ◽  
2021 ◽  
Vol 26 (21) ◽  
pp. 6383
Author(s):  
Elena Gómez ◽  
Pedro Velho ◽  
Ángeles Domínguez ◽  
Eugénia A. Macedo
Keyword(s):  
Thermal Analysis ◽  
Differential Scanning Calorimetry ◽  
Heat Capacity ◽  
Ionic Liquids ◽  
Thermal Behavior ◽  
Binary Mixtures ◽  
Heat Capacities ◽  
Viable Alternative ◽  
Transition Temperatures ◽  
Scanning Calorimetry

Ionic liquids (ILs) are being widely studied due to their unique properties, which make them potential candidates for conventional solvents. To study whether binary mixtures of pure ionic liquids provide a viable alternative to pure ionic liquids for different applications, in this work, the thermal analysis and molar heat capacities of five equimolar binary mixtures of ionic liquids based on imidazolium, pyridinium, pyrrolidinium, and piperidinium cations with dicyanamide, trifluoromethanesulfonate, and bis(trifluoromethylsulfonyl)imide anions have been performed. Furthermore, two pure ionic liquids based on piperidinium cation have been thermally characterized and the heat capacity of one of them has been measured. The determination and evaluation of both the transition temperatures and the molar heat capacities was carried out using differential scanning calorimetry (DSC). It was observed that the thermal behavior of the mixtures was completely different than the thermal behavior of the pure ionic liquids present, while the molar heat capacities of the binary mixtures were very similar to the value of the average of molar heat capacities of the two pure ionic liquids.

scholarly journals Dissolution of Chitin in Deep Eutectic Solvents Composed of Imidazolium Ionic Liquids and Thiourea

2019 ◽  
Vol 3 (4) ◽  
pp. 90 ◽  
Author(s):  
Satoshi Idenoue ◽  
Kazuya Yamamoto ◽  
Jun-ichi Kadokawa
Keyword(s):  
Hydrogen Bond ◽  
Ionic Liquid ◽  
Ionic Liquids ◽  
Room Temperature ◽  
Ccd Camera ◽  
Deep Eutectic Solvents ◽  
The Other ◽  
Imidazolium Ionic Liquids ◽  
Eutectic Mixtures ◽  
Organic Resource

Chitin is an abundant organic resource but shows poor solubility, leading to difficulty in utilization as materials. We have already reported that an ionic liquid (IL), 1-allyl-3-methylimidazolium bromide, dissolves chitin at concentrations up to ca. 5 wt %. However, the color of the resulting solution is blackened, mainly owing to the presence of bromide. On the other hand, some deep eutectic solvents (DESs) have been already reported to dissolve chitin. In this study, we found that DESs composed of imidazolium ILs and thiourea dissolved chitin without obvious coloring. DESs are systems formed from eutectic mixtures of hydrogen bond accepters and donors. We first prepared DESs by heating mixtures of imidazolium ILs with thiourea at 100 °C for 30 min with stirring. Predetermined amounts of chitin were then added to the DESs, and for the dissolution, the mixtures were left standing at room temperature for 24 h, followed by heating at 100 °C for 24 h with stirring. The dissolution processes were evaluated by CCD camera views, which revealed in most cases the dissolution of chitin at 2–5 wt % concentrations with the present DESs.

scholarly journals Comprehensive Thermal Characteristics of Different Cultivars of Flaxseed Oil (Linum usittatissimum L.)

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 1958
Author(s):  
Jolanta Tomaszewska-Gras ◽  
Mahbuba Islam ◽  
Liliana Grzeca ◽  
Anna Kaczmarek ◽  
Emilia Fornal
Keyword(s):  
Differential Scanning Calorimetry ◽  
Heating Rate ◽  
Fatty Acid Content ◽  
Thermal Characteristics ◽  
Principal Component ◽  
Flaxseed Oil ◽  
Scanning Calorimetry ◽  
Total Oxidation ◽  
Increasing Temperature ◽  
Linear Correlations

The aim of this study was to describe the thermal properties of selected cultivars of flaxseed oil by the use of the differential scanning calorimetry (DSC) technique. The crystallization and melting profiles were analyzed depending on different scanning rates (1, 2, 5 °C/min) as well as oxidative induction time (OIT) isothermally at 120 °C and 140 °C, and oxidation onset temperatures (Ton) at 2 and 5 °C/min were measured. The crystallization was manifested as a single peak, differing for a cooling rate of 1 and 2 °C/min. The melting curves were more complex with differences among the cultivars for a heating rate of 1 and 2 °C/min, while for 5 °C/min, the profiles did not differ, which could be utilized in analytics for profiling in order to assess the authenticity of the flaxseed oil. Moreover, it was observed that flaxseed oil was highly susceptible to thermal oxidation, and its stability decreased with increasing temperature and decreasing heating rate. Significant negative linear correlations were found between unsaturated fatty acid content (C18:2, C18:3 n-3) and DSC parameters (OIT, Ton). Principal component analysis (PCA) also established a strong correlation between total oxidation value (TOTOX), peroxide value (PV) and all DSC parameters of thermo-oxidative stability.

Solidification of Ionic Liquids: Theory and Techniques

2010 ◽  
Vol 63 (4) ◽  
pp. 544 ◽  
Author(s):  
Anja-Verena Mudring
Keyword(s):  
Phase Transition ◽  
Ionic Liquid ◽  
Ionic Liquids ◽  
Solid Phase ◽  
Soft Materials ◽  
Separation Science ◽  
Vast Number ◽  
Plastic Crystals ◽  
Thermal Fluids ◽  
Solid Phase Transition

Ionic liquids (ILs) have become an important class of solvents and soft materials over the past decades. Despite being salts built by discrete cations and anions, many of them are liquid at room temperature and below. They have been used in a wide variety of applications such as electrochemistry, separation science, chemical synthesis and catalysis, for breaking azeotropes, as thermal fluids, lubricants and additives, for gas storage, for cellulose processing, and photovoltaics. It has been realized that the true advantage of ILs is their modular character. Each specific cation–anion combination is characterized by a unique, characteristic set of chemical and physical properties. Although ILs have been known for roughly a century, they are still a novel class of compounds to exploit due to the vast number of possible ion combinations and one fundamental question remains still inadequately answered: why do certain salts like ILs have such a low melting point and do not crystallize readily? This Review aims to give an insight into the liquid–solid phase transition of ILs from the viewpoint of a solid-state chemist and hopes to contribute to a better understanding of this intriguing class of compounds. It will introduce the fundamental theories of liquid–solid-phase transition and crystallization from melt and solution. Aside form the formation of ideal crystals the development of solid phases with disorder and of lower order like plastic crystals and liquid crystals by ionic liquid compounds are addressed. The formation of ionic liquid glasses is discussed and finally practical techniques, strategies and methods for crystallization of ionic liquids are given.

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