Dissertations / Theses on the topic 'Ionic liquid (IL)'
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1
Bara, Jason Edward. "New ionic liquids and ionic liquid-based polymers and liquid crystals for gas separations." Connect to online resource, 2007. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3256439.
2
Coles, Samuel. "Interfacial nanostructure of solvate ionic liquids and ionic liquid solutions." Thesis, University of Oxford, 2018. https://ora.ox.ac.uk/objects/uuid:89c797e4-e000-4c8c-b6b8-ffa5ed202a4d.
Abstract:
The technology employed by human beings for the generation, storage and usage of energy is presently undergoing the fastest and most profound change since the industrial revolution. The changes in the generation and usage of energy necessitate the development of new methods of energy storage. In these systems, electrochemical energy storage will play a crucial role and to this end new electrolytes need to be explored to complement these changes. One such class of liquids is ionic liquids, a class of salts that are molten at room temperature. These liquids have a broad applicability to batteries and supercapacitors. This thesis details work where molecular dynamics simulations have been used to explore the nanostructure of ionic liquids and their mixtures with various molecular solvents at simplistic electrodes. The thesis has two broad sections. The first is covered in Chapter 3, and explores the nanostructure of ionic liquid propylene carbonate solutions, developing a framework through which these nanostructures can be understood. The section concludes that the increasing dilution of ionic liquids decreases the surface charge at which the characteristic ionic liquid oscillatory interfacial structure gives way to a different structure featuring monotonic charge decay. The behaviour of ionic liquids at interfaces is found to be correlated to ion size and type, as well as concentration. A wide divergence in the observed behaviour is shown at positive and negative electrodes due to the asymmetry of propylene carbonate. The second section, consisting of two chapters, explores the interfacial nanostructure of solvate ionic liquids using two different boundary conditions to model the electrode. This work is the first simulation of solvate ionic liquids at electrified interfaces. This section will explore the effect of electrode model on the behaviour of these ionic liquids at the electrode. Chapter 4 uses a fixed charge electrode, whereas Chapter 5 uses one with a fixed potential. The section concludes that regardless of electrode model, the idealised portrait of a solvate ionic liquid - one where the liquid behaves exactly as an aprotic ionic liquid - is not applicable. In Chapter 4's exploration of fixed charged electrodes, the formation of 2 glyme to lithium complexes contradicts the idealised portrait of the liquid. A different change is observed in Chapter 5's exploration of fixed potential electrodes, with both lithium glyme and lithium anion clusters forming at the interface. The key difference between the two studies is that lithium does not coordinate to the electrode in the fixed charge simulations, while in the fixed potential case it does. At the end of Chapter 5 the results are compared against experimental data, with the efficacy of the two models discussed. The aim of both studies is to look at the nanostructure of ionic liquids, when the symmetry between co-ion and cation repulsion - and related effects - is broken by the presence of a non ionic constituent in the liquid.
3
LATINI, GIULIO. "Bio-based ionic liquids and poly(ionic liquid)s for CO2 capture." Doctoral thesis, Politecnico di Torino, 2021. http://hdl.handle.net/11583/2912980.
4
Zgonnik, Viacheslav. "Elle & il : enantioselective liquid-liquid extraction and ionic liquids." Toulouse 3, 2011. http://thesesups.ups-tlse.fr/1297/.
Abstract:
L'extraction liquide-liquide énantiosélective (ELLE) consiste en l'extraction d'un énantiomère à partir d'un mélange racémique par transfert entre deux phases liquides. Cette technologie est très prometteuse pour l'obtention des composés énantiopurs et devient l'objet d'une forte attention les dernières années grâce au développement de l'équipement approprié qui permet de réduire le temps et le prix de la séparation des énantiomères. L'objectif essentiel pour l'introduction d'ELLE dans le monde industriel est la découverte d'hôtes chiraux fiables, peu chers, durables, sélectifs et applicables à une large gamme de substances chirales. Dans ce travail, la possibilité d'effectuer l'ELLE dans un milieu ionique chiral a été vérifiée. De nombreux nouveaux liquides ioniques chiraux ont été préparés pour jouer le rôle des hôtes chiraux. Le meilleur exemple montre un excès énantiomérique de 30% et une sélectivité opérationnelle de 1,97. Ceci représente le premier exemple d'ELLE utilisant les liquides ioniques chiraux et sans usage d'ions métalliquesEnantioselective liquid-liquid extraction (ELLE) is an implementation of the extraction of one enantiomer from a racemic mixture by the transfer between two liquid phases. This technology is very promising for obtaining enantiopure compounds and becomes the object of much attention in recent years after the development of appropriate equipment that reduces the time and cost of the separation of enantiomers. The major objective for the successful introduction of ELLE to industrial world is the discovery of reliable, inexpensive and durable chiral hosts selective for a wide range of chiral substances. In this work the possibility of performing ELLE in chiral ionic liquids environment was verified. Many new chiral ionic liquids were prepared to play the role of chiral hosts. The best example shows enantiomeric excess of 30% and operational selectivity of 1. 97. This represents the first example of using chiral ionic liquids in ELLE and without metallic ions
5
Abai, M. "Ionic liquids for mercury removal from liquid hydrocarbons." Thesis, Queen's University Belfast, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.545997.
6
Sheppard, O. "Structural and liquid crystalline properties of ionic liquids." Thesis, Queen's University Belfast, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.431482.
7
Ashworth, Claire. "A computational investigation of local interactions within ionic liquids and ionic liquid analogues." Thesis, Imperial College London, 2015. http://hdl.handle.net/10044/1/58256.
Abstract:
The potential applications of ionic liquids and related analogues are diverse. However, for large-scale industrial applications low cost ionic liquids are required. Moreover, for the full potential of ionic liquids to be realised, a fundamental link between molecular level interactions, structuring and the bulk phase properties must be established. Deep eutectic solvents (DESs) and protic ionic liquids have been identified as candidates for the potential application of chalcopyrite leaching. The choline chloride – urea DES and 1- butylimidazolium hydrogensulphate protic ionic liquid were selected as systems of primary interest. Local structuring within the selected systems has been investigated, with an emphasis on the hydrogen bonding interactions. The choline chloride – urea mixture is a prototypical example of a DES. Using DFT, the pairwise interactions between the constituent components, and within clusters composed of n.urea.choline-chloride (n = 1-3), have been evaluated. Many different types of hydrogen bond have been identified, exhibiting flexibility in both strength and number. The formation of the commonly proposed [2urea⋅Cl]– complexed anion has been scrutinised and found to be energetically competitive with other interactions. Moreover, contrary to existing proposals, the negative charge is found to remain localised on chloride. The cation-anion and anion-anion interactions within [C4Him][HSO4] and related systems have been compared and contrasted;; ion pairs were evaluated using DFT and the bulk systems modelled using classical MD. Local structuring within [C4Him][HSO4] exhibits features of both the aprotic analogue and alkylammonium protic ionic liquids. [HSO4]–⋅⋅⋅[HSO4]– interactions have been considered and found to be a notable feature of the [HSO4]– ionic liquids studied. It is anticipated that the formation of [HSO4]– aggregates influences the properties of the bulk systems. A QM/MM method for the study of ionic liquids is introduced. Preliminary analysis suggests that this is a viable approach for the investigation of local structuring within ionic liquids.
8
Hall, L. S. I. "Supported ionic liquid catalysis." Thesis, Queen's University Belfast, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.676492.
Abstract:
Over the last few years interest in supported ionic liquid (IL) catalysis has been growing. This is due to the increased selectivity and catalytic activity obtained in IL based systems compared with molecular solvents coupled with the advantages of solid catalyst in terms of separation. In this thesis, the effect of supported ionic liquid catalysis will be examined for various different reactions including the hydrogenation of citral and cinnamaldehyde, the Diels-Alder, Mukaiyama aldol and carbonyl-ene reactions. Solid catalyst ionic liquid layers (SCILL) catalysts and Ionic polymers (IP) were used for the hydrogenation of citral and cinnamaldehyde. Overall a Pd/Ab03 with and without an IL produced significantly higher selectivities and conversions compared with a Pd/C catalyst. The IP catalysts were shown to greatly increase the selectivity. The IP synthesised from the commercial Amberlite 910, produced the best results for both substrates achieving high selectivities up to 99%.
9
Yang, Junhong. "GLASS FORMATION BEHAVIOR AND IONIC CONDUCTIVITY OF IONIC LIQUIDS AND POLYMERIC IONIC LIQUID: INSIGHT FROM MOLECULAR SIMULATION." University of Akron / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=akron1494886213137829.
10
Bernhem, Kristoffer. "How ionic are ionic liquids?" Thesis, KTH, Skolan för kemivetenskap (CHE), 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-41033.
Abstract:
Ionic liquids are continuously finding more and more applications, both in research and in the industry. Many attempts have been made to find parameters that could be used to describe all ionic liquid systems. Five years ago a Japanese group applied the work of Gutmann on ionic liquids to use ionic association to describe solvation effects. The group calculated ionic association from conductivity and diffusion measurements. This report presents a direct approach through electrophoretic NMR to measure ionic association in ionic liquids. The report contains a brief introduction to ionic liquids and their properties as well as a short explanation of Nuclear Magnetic Resonance (NMR) spectroscopy, diffusion NMR and a more detailed explanation of electrophoretic NMR (eNMR). Experimental setups, taken from previous work by the NMR group at Physical Chemistry KTH, have been modified to allow for measurements in ionic liquid systems. The report discusses the issues that can arise when measuring eNMR in ionic liquids and suggests solutions. The method developed is principally built upon experiments on 1-butyl-3-methyl-imidazolium trifluoroacetate and is directly applicable to other ionic liquid systems. For more viscous systems than the one investigated here, slight changes will need to be made, as explained in the report. In order to evaluate the method developed during the project the degree of association for 1-butyl-3-methyl-imidazolium trifluoroacetate has been calculated from experimental results and results in similar values as reported by Tokuda et al.. Furthermore, the temperature variation due to Joule heating during a complete eNMR experiment was also investigated by observing change in chemical shift.
11
Hjalmarsson, Nicklas. "Ionic liquids : The solid-liquid interface and surface forces." Doctoral thesis, KTH, Yt- och korrosionsvetenskap, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-186267.
Abstract:
Ionic liquids (ILs) present new approaches for controlling interactions at the solid-liquid interface. ILs are defined as liquids consisting of bulky and asymmetric ions, with a melting point below 373 K. Owing to their amphiphilic character they are powerful solvents but also possess other interesting properties. For example, ILs can self-assemble and are attracted to surfaces due to their charged nature. As a result, they are capable of forming nanostructures both in bulk and at interfaces. This thesis describes how the solid-IL interface responds to external influences such as elevated temperatures, the addition of salt and polarisation. An improved understanding of how these factors govern the surface composition can provide tools for tuning systems to specific applications such as friction. Normal and friction forces are measured for ethylammonium nitrate (EAN) immersed between a mica surface and a silica probe, at different temperatures or salt concentrations. The results demonstrate that an increase in temperature or low concentrations of added salt only induce small changes in the interfacial structure and that the boundary layer properties remain intact. In contrast, at sufficiently large salt concentrations the smaller lithium ion prevails and the surface composition changes. The interfacial layer of a similar IL is also investigated upon the addition of salt and the results reveal that lithium ions affect the surface composition differently depending on the ion structure of the IL. This demonstrates that the surface selectivity strongly depends on the ion chemistry. Remarkably, a repulsive double layer force manifests itself for EAN at 393 K, which is not observed for lower temperatures. This indicates a temperature dependent change in EAN’s microscopic association behaviour and has general implications for how ILs are perceived. A new method is developed based on a quartz crystal microbalance to investigate how the surface compositions of ILs respond to polarisation. The approach demonstrates that interfacial layers of both a neat IL and an IL dissolved in oil can be controlled using potentials of different magnitudes and signs. Furthermore, the method enables two independent approaches for monitoring the charges during polarisation which can be used to quantify the surface composition. The technique also provides information on ion kinetics and surface selectivity. This work contributes to the fundamental understanding of the solid-IL interface and demonstrates that the surface composition of ILs can be controlled and monitored using different approaches.Jonvätskor möjliggör nya tillvägagångssätt för att kontrollera interaktioner vid gränsskiktet mellan fasta ytor och vätskor. Jonvätskor definieras som vätskor som består av stora och asymmetriska joner med en smältpunkt under 373 K. På grund av sin amfifila karaktär är de starka lösningsmedel men har också andra intressanta egenskaper. Jonvätskor kan till exempel självorganisera sig och attraheras till ytor på grund av sin laddning. En följd av detta är att de bildar nanostrukturer både i bulk och på ytor. Denna avhandling beskriver hur gränsskiktet mellan fasta ytor och jonvätskor svarar på yttre påverkan såsom en ökning i temperatur, tillsättning av ett salt samt polarisering. En ökad förståelse för hur dessa faktorer styr ytkompositionen av jonvätskor kan bidra med verktyg för att kontrollera system till specifika applikationer såsom friktion. Normala- och friktionskrafter mäts för etylammonium nitrat (EAN) mellan en glimmeryta och en kolloidprob vid olika temperaturer eller saltkoncentrationer. Resultaten visar att en ökning av temperatur eller låga koncentrationer av tillsatt salt bara marginellt framkallar ändringar i strukturen på gränsytan och att det adsorberade lagret förblir intakt. När saltkoncentrationen emellertid var tillräckligt hög får den mindre litiumjonen överhanden och ytsammansättningen ändras. Ytlagret av en liknande jonvätska undersöks också vid tillsättning av salt och resultaten avslöjar att litiumjoner påverkar ytsammansättningen annorlunda beroende på jonstrukturen av jonvätskan. Detta visar att ytselektiviteten starkt beror på jonkemin. En repulsiv dubbellagerkraft yttrar sig anmärkningsvärt för EAN vid 393 K vilket inte observeras vid lägre temperaturer. Detta indikerar en ändring i EANs mikroskopiska sammansättningsbeteende och har generella återverkningar för hur jonvätskor uppfattas. En ny metod har utvecklats baserad på en kvartskristall mikrovåg för att undersöka hur ytsammansättningen av jonvätskor reagerar på polarisering. Denna metod visar att det adsorberade lagret av både en ren jonvätska och en jonvätska löst i olja kan kontrolleras genom att applicera spänningar med olika tecken och storlekar. Dessutom möjliggör metoden två oberoende tillvägagångssätt för att övervaka laddningarna under polarisering vilket kan användas för att kvantifiera ytsammansättningen. Tekniken ger också information om jonkinetik och ytselektivitet. Detta arbete bidrar till den grundläggande förståelsen av gränsskiktet mellan fasta ytor och jonvätskor och visar att ytsammansättningen av jonvätskor kan kontrolleras och övervakas med olika tillvägagångssätt.
QC 20160518
12
Du, Xi. "Membrane Drying of Ionic Liquid." University of Toledo / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1353077367.
13
Stoffers, Martin [Verfasser]. "Liquid-Liquid Extraction of n-Butanol from Aqueous Solutions Using Ionic Liquids / Martin Stoffers." München : Verlag Dr. Hut, 2014. http://d-nb.info/1055863524/34.
14
Martinho, Susana Teresa Antunes. "Development of new oxygen therapeutics using fluorinated ionic liquids." Master's thesis, Faculdade de Ciências e Tecnologia, 2012. http://hdl.handle.net/10362/8482.
Abstract:
Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau Mestre em
Engenharia BiomédicaThe last decade of the 20th century has yielded a remarkable progress in the field of first generation artificial blood substitutes. Emulsions based on perfluorocarbons (PFCs) became one of the main candidates for a safe and reliable artificial blood substitute. The final objective of the present work is to study the fluorinated ionic liquids (FILs) with the purpose of replacing, partially or totally, the PFCs actually used as artificial blood substitutes, thus providing new fluids with tailored advanced properties. With this goal in mind, the thermophysical and thermodynamic characterization of several FILs, was carried out with the aim to select the most appropriate candidate. This characterization involves the measurement and analysis of the decomposition and melting temperature, density, viscosity, refractive index, and ionic conductivity at atmospheric pressure in a temperature range from 298.15 to 353.15 K. Furthermore, the liquid-liquid equilibria of binary mixtures of PFCs and FILs were studied, at atmospheric pressure in a temperature range usually from 293.15 to 343.15 K. The knowledge of the phase behaviour is crucial to the formulation of emulsions used nowadays as suitable oxygen carriers. Finally, Non-Random Two Liquid (NRTL) thermodynamic model was successfully applied to correlate the behaviour of the binary mixtures of PFCs and FILs
15
Pontzen, Florian [Verfasser]. "Continuous liquid-liquid biphasic catalysis with ionic liquids : process development, characterisation and optimisation / Florian Pontzen." Aachen : Hochschulbibliothek der Rheinisch-Westfälischen Technischen Hochschule Aachen, 2011. http://d-nb.info/1018216111/34.
16
He, Xun 1968. "Functionalized ionic liquid-supported organic synthesis." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=102984.
Abstract:
Ionic liquid-supported synthesis is a new concept in organic chemistry. This concept has been well demonstrated in this thesis including ionic-liquid-supported Swern oxidation, oligosaccharide synthesis, imidazolium oligomer synthesis and peptide synthesis.Ionic liquid-supported Swern oxidation provided a new odorless approach to oxidize primary and secondary alcohols into aldehydes and ketones as compared to the conventional method where DMSO was used as an oxidant and the toxic and volatile compound dimethylsulfide was generated quantitatively. The new ionic liquid-supported organosulfur reagents were thermally stable, nonvolatile and odorless, which were recoverable and recyclable after Swern oxidation.
Chapter 3 of this thesis described the first example in the research field of ionic liquidsupported oligosaccharide synthesis. This new approach possesses the advantages of both conventional solution phase synthesis and solid phase-supported synthesis. It made possible the chemical assembling of glycals and the cleavage of oligosacharide from the support without need of chromatography to purify the products.
Ionic liquid-type oligomers were designed to solve the problems involved in the oneionic-unit ionic liquid-supported biopolymer synthesis because these compounds could have stronger ionic effects on support-bound molecules, which made easier the chemical assembling and purifications of large biopolymers than one-ionic-unit ionic liquidsupported organic synthesis. The thermogravimetric analysis (TGA) showed that these imidazolium oligomers have very good thermal stability. They also have great potential application in the electrochemistry.
Imidazolium oligomer-supported peptide synthesis provided a new approach to prepare peptides in a straightforward way. The amino acid coupling reactions were conducted in homogeneous solution phase, which did not require largely excess of reagents to push the reaction to completion and the purification could be performed in a simple way such as centrifugation, decantation and washing without need of special solvents. Moreover, the cleavage of the peptide from the imidazolium oligomer support was done by hydrolysis under basic conditions and the product was obtained in NMR and MS purity. Importantly, imidazolium oligomer-supported peptide block coupling proceeded very well, which provided an approach to convergently synthesize peptides. This approach is very useful for the peptide synthesis in industry especially for the synthesis of peptides with less than 20 amino acids.
17
O'Toole, Sarah. "Electrochemical studies in ionic liquid media." Thesis, Queen's University Belfast, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.479403.
18
Fraser, Georgina. "Ionic liquid effects on nucleophilic substitutions." Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/17827.
Abstract:
In this thesis we demonstrate a fundamental difference between nucleophilic substitution reaction mechanisms in ionic liquids versus conventional solvents. Reported herein are the effects of ionic liquid solvents on substitution reactions between a cationic electrophile and the chloride anion of various organic and inorganic salts. We have combined novel quantitative studies of the nucleophilic source [Cat]Cl with our studies of [C4C1im]Cl and compared their reactivities, k2. For the first time, Eyring activation parameters have been calculated for substitution reactions between charged species in ionic liquid solvents and reveal a hitherto unprecedented role of the cation in the transition state. The activation parameters (ΔH≠ and ΔS≠) suggest the reactivity of the chloride anion can be manipulated by varying the size and chemical nature of the cation, and also shed light on cation hydrogen bond donating effects. The superior ability of ionic liquid solvents to fully screen the charges of reactant ions is shown to break down as ions become larger, less charge dense and display a tendency to self-aggregate.
19
Marley, Eunan. "Electrochemical reactivity in ionic liquid media." Thesis, Queen's University Belfast, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.675853.
Abstract:
In our work, a number of reaction processes were investigated, using ionic liquids (ILs), or ionic liquid-based salts, as either the solvent or reactant. In chapter 3, the active form of TEMPO, the oxoammonium cation (T+), was used to synthesise T+ -bis(trifluoromethylsulfonyl)imide (NTf2) and T+trifluoromethanesulfonate (triflate) salts. These salts were used to investigate the mediated oxidation of primary alcohols. It was found that the oxidation process proceeded more rapidly for methanol than for the other two alcohols investigated. A significant drop in T+ current occurred when only base was added to the cell, with a multistep reaction process likely to be involved. The use of a solid DOWEX resin as base was also briefly investigated. In chapter 4, the electrocarboxylation of a number of benzophenone derivatives was investigated. For all investigated compounds, the carboxylation process proceeded via a ECE / DISPl mechanism. It has been found that the variation of the carboxylation reaction kinetics can be predicted based on the nature of the functional groups present on the benzene rings. Electron donating groups increased the rate of carboxylation, while electron withdrawing groups decreased the rate of carboxylation. The electrocarboxylation in I -butyl-lmethylpyrrolidinium bis-(trifluoromethane sulfonyl)imide [Bmpy][NTfz] were 2 orders of magnitude slower than those reported in DMF. In chapter 5, CO2 reduction in [Bmpy][NTfz] was briefly investigated at a number of electrode types (glassy carbon, platinum, palladium, gold, indium) using cyclic voltammetry. CO2 reduction was observed at all 5 electrodes, where it was found that Au and especially In act as electrocatalysts. The mediated reduction of COz in [Bmpy] [NTfz] was then attempted using methyl benzoate and dimethyl phthalate. Investigation of the electrochemistry of the two compounds in IL suggests that ion pairing causes an increase in the rate of dimerization over carboxylation, preventing the ester from acting as a redox mediator.
20
Brandt, Agnieszka. "Ionic liquid pretreatment of lignocellulosic biomass." Thesis, Imperial College London, 2012. http://hdl.handle.net/10044/1/9166.
Abstract:
This thesis is concerned with the thermal treatment of lignocellulosic biomass using ionic liquids for the purpose of comminution via dissolution, for fractionating the biological composite and for obtaining aqueous solutions of carbohydrate monomers from the pulp via enzymatic hydrolysis. A major focus was the relationship between the choice of the anion and the effectiveness of the treatment. The synthesis of a range of 1-butyl-3-methylimidazolium ionic liquids with strongly hydrogen-bond basic anions was accomplished. Selected, process-relevant physicochemical properties were measured, such as the Kamlet-Taft solvent polarity, hygroscopicity and thermal stability. It was shown that 1-butyl-3-methylimidazolium acetate is not stable at 120°C, while other ionic liquids e.g. 1-butyl-3-methylimidazolium hydrogen sulfate exhibit very good long-term thermal stability. It was shown that hydrogen-bond basic 1-butyl-3-methylimidazolium ionic liquids attract more than stoichiometric quantities of water when exposed to air, suggesting that ionic liquid pretreatment under anhydrous conditions is difficult to achieve. Dissolution of air-dried wood chips in 1-butyl-3-methylimidazolium ionic liquids was attempted. It was shown that the large particle size and the moisture contained in the biomass hamper complete dissolution. The hydrogen-bond basicity of the ionic liquid, described by the Kamlet-Taft parameter ß, was correlated with the ability to expand as well as partially and anisotropically dissolve wood chips. Pretreatment of lignocellulosic biomass with 1-butyl-3- methylimidazolium methyl sulfate, 1-butyl-3-methylimidazolium hydrogen sulfate and 1-butyl-3-methylimidazolium methanesulfonate was explored and high saccharification yields were reported. It was found that successful application of methyl sulfate and hydrogen sulfate ionic liquids requires addition of water and that comparatively high water contents are tolerated. Fractionation of lignocellulose into an insoluble cellulose fraction, a solubilised hemicellulose fraction and a lignin containing precipitate was achieved. The influence of water content, pretreatment time and biomass type on the enzymatic saccharification yield and the extent of hemicellulose solubilisation, hydrolysis and dehydration were examined.
21
Waichigo, Martin M. "Alkylammonium Carboxylates as Mobile Phases for Reversed-Phase Liquid Chromatography." Miami University / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=miami1134142423.
22
Davidson, Jacob Daniel. "Actuation and Charge Transport Modeling of Ionic Liquid-Ionic Polymer Transducers." Thesis, Virginia Tech, 2010. http://hdl.handle.net/10919/31204.
Abstract:
Ionic polymer transducers (IPTs) are soft sensors and actuators which operate through a coupling of micro-scale chemical, electrical, and mechanical mechanisms. The use of ionic liquid as solvent for an IPT has been shown to dramatically increase transducer lifetime in free-air use, while also allowing for higher applied voltages without electrolysis. This work aims to further the understanding of the dominant mechanisms of IPT actuation and how these are affected when an ionic liquid is used as solvent. A micromechanical model of IPT actuation is developed following a previous approach given by Nemat-Nasser, and the dominant relationships in actuation are demonstrated through an analysis of electrostatic cluster interactions. The elastic modulus of Nafion as a function of ionic liquid uptake is measured using uniaxial tension tests and modeled in a micromechanical framework, showing an excellent fit to the data. Charge transport is modeled by considering both the cation and anion of the ionic liquid as mobile charge carriers, a phenomenon which is unique to ionic liquid IPTs as compared to their water-based counterparts. Numerical simulations are performed using the finite element method, and a modified theory of ion transport is discussed which can be extended to accurately describe electrochemical migration of ionic liquid ions at higher applied voltages. The results presented here demonstrate the dominant mechanisms of IPT actuation and identify those unique to ionic liquid IPTs, giving directions for future research and transducer development.Master of Science
23
Anaredy, Radhika Sudhakar. "The study of ionic liquid behavior at solid-liquid interfaces." Diss., University of Iowa, 2018. https://ir.uiowa.edu/etd/6540.
Abstract:
Ionic liquids are organic salts with room temperature melting points. Their unique physicochemical properties make them popular choices in the fields of tribology, energy storage and production, and extractions. Previous studies show that IL’s interfacial volume, extending some nanometers from an adjacent surface, is characterized by the self-assembly of IL molecules into ordered structures. This ordering imparts unique properties which often govern the properties of ILs and affect their application in the aforementioned areas. This thesis describes research conducted to understand the behaviors and interactions of ILs at interfaces, along with investigations of bulk IL structures and transitions in the presence of water. The findings reported will help the scientific community by giving insight into the physical and chemical processes surrounding IL behavior, allowing ILs’ physicochemical properties to be more accurately tailored, via judicious synthesis, to a desired application.
Major findings of this work show that the ordered interfacial region may extend up to two orders of magnitude further from the interface than previously thought. Specifically, this thesis shows several examples of reversible IL self-assembly into long-range ordered films that extend up to ~ 2 μm from a surface. This is approximately twelve times the thickness of interfacial region previously reported.
Temperature controlled studies on the bulk structure of an IL at its phase transition temperatures aid in understanding the structural arrangement of molecules in the bulk fluid as a function of temperature. Spectroscopic analyses of these bulk studies and the above interfacial systems showed no similarities, indicating that the self-assembled interfacial structures are, in fact, unique.
Being hygroscopic in nature, water is the most common impurity found in ILs. Water can affect IL intermolecular forces and the resulting structures in bulk fluids as well as at the interface. One of the chapter of this thesis describes these interactions, and the variably hydrated IL structures for two classes of ILs via spectroscopic and electrochemical techniques.
The outcomes of this thesis will aid the community in understanding interfacial and bulk structures of ILs, as well as influences of temperature and water on these structures. The description of extended IL structures provides valuable insights into new design principles for truly task-specific ILs.
24
DONALD, GREGORY THOMAS. "Model Chiral Ionic Liquids for High Performance Liquid Chromatography Stationary Phases." University of Cincinnati / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1214325450.
25
Ternova, Dariia. "Malonamide, phosphine oxide and calix[4]arene functionalized ionic liquids : synthesis and extraction of actinides and lanthanides." Thesis, Strasbourg, 2014. http://www.theses.fr/2014STRAE041/document.
Abstract:
Le retraitement des déchets radioactifs est un problème crucial de nos jours. Ce travail est dédié au développement de nouveaux systèmes d'extraction des radionucléides sur la base de solvants "verts", les liquides ioniques (LI). Dans ce but, des LI ont été fonctionnalisés avec des motifs variés : oxyde de phosphine, carbamoyl oxyde de phosphine et fragments malonamides. De même, les plateformes calix[4]arènes ont été utilisées pour la synthèse de LI fonctionnalisés (LIF) et de leurs précurseurs. Des LIF de deux types (cationiques et anioniques) ont été obtenus.Les LIF synthétisés ont été testés pour l'extraction liquide/liquide de radionucléides. Il a été montré que l'extraction est bien due aux motifs extractants. Toutefois, la charge de l'ion modifié influence l'extraction.Différentes expériences d'extraction et une modélisation mathématique ont été effectuées pour déterminer les mécanismes d'extraction. Ces études ont montré que chacun des systèmes d'extraction est caractérisé par un ensemble d'équilibres d'extraction différent, basés essentiellement sur l'échange cationiqueRadioactive waste treatment is a crucial problem nowedays. This work was dedicated to the development of the new extracting systems for radionuclides on the basis of "green" solvents Ionic Liquids {Ils). For this purpose Ils were functionalized with various extracting patterns: phosphine oxide, carbamoyl phosphine oxide groups and malonamide fragment. Also the calix[4]arene platforms were used for the synthesis of functionalized ionic liquids (Fils) and their precursors. The Fils of both types cationic and anionic have been obtained. The synthesized Fils were tested for the liquid-liquid extraction of radionuclides. lt was found that extraction well occurs due to the extracting patterns, however a charge of a modified ion influences extraction.The various extracting experiments and mathematical modelling have been performed to determine the mechanisms of extraction. These studies showed that each extracting system is characterized by a different set of extracting equilibria, based mostly on cationic exchange
26
Marcolongo, Alberto. "Synthesis and characterization of polymeric ionic liquid through free radical polymerization of acryloyl imidazolium-based ionic liquid monomer." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amslaurea.unibo.it/8550/.
Abstract:
This thesis investigates the synthesis of polymeric ionic liquid [(poly-acryloyloxy)6C6C1im][NTf2], by free radical polymerization of acryloyl imidazolium-base ionic liquid monomer [(acryloyloxy)6C6C1im][NTf2]. Moreover, the smartest synthetic route to obtain this monomer was investigated. Two different synthesis were compared. The first one started from the preparation of the monomer 6-chlorohexyl acrylate followed by substitution and metathesis to reach ionic liquid monomer. The second one started from synthesis of the ionic liquid [(HO)6C6C1im]Cl followed by metathesis and esterification in order to get ionic liquid monomer [(acryloyloxy)6C6C1im][NTf2].
27
Ekka, Deepak. "Thermophysical studies on ionic liquids and amino acids in some liquid systems." Thesis, University of North Bengal, 2014. http://ir.nbu.ac.in/handle/123456789/1490.
28
Joshi, Manishkumar Dilipkumar. "Synthesis of New Classes of Ionic Liquids and Polymeric Ionic Liquids and their Applications in Microextraction Techniques." University of Toledo / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1372871956.
29
Najafi, Ali. "Application of Polymeric Ionic Liquid Solid-Phase Microextraction Sorbent Coatings and Ionic Liquid Stationary Phases for Liquid and Multidimensional Gas Chromatographic Techniques." University of Toledo / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1449846148.
30
Ferreira, Fábio Miguel Mendes. "Valorization of pharmaceutical wastes using ionic liquids." Master's thesis, Universidade de Aveiro, 2014. http://hdl.handle.net/10773/13789.
Abstract:
Mestrado em Biotecnologia - Biotecnologia Industrial e AmbientalThe main objective of the present work is the application of aqueous biphasic systems (ABS) with ionic liquids (ILs) in the extraction of pharmaceutical wastes. Nowadays, after their expiration date time recovered medicine waste are incinerated, destroying most of the valuable compounds present, with only a minor thermic valorisation. Therefore the development of new processes that allow this wastes valorization is crucial to create a more environmentally friendly process and the use of wastes as a source of raw materials. The development of new ABS with ILs and their study allowed the optimization of the extraction of paracetamol and caffeine. Finally the application of this simple and fast process to a medical waste (ALGIK) resulted in a complete extraction of both paracetamol and caffeine.
Este trabalho tem como objetivo estudar a aplicação de sistemas aquosos bifásicos (SAB) com líquidos iónicos (LIs) na extração de compostos ativos de resíduos farmacêuticos. Atualmente os medicamentos fora do mercado são recolhidos e incinerados, sendo por isso a totalidade dos compostos ativos de interesse perdidos por combustão completa. Apesar da valorização energética destes resíduos há grandes perdas ao nível dos vários compostos presentes. Deste modo o desenvolvimento de novos processos simples de extração com vista a’ valorização dos compostos ativos presentes nos mesmos é de grande importância, minimizando os impactos ambientais e permitindo a utilização destes resíduos como fonte de matérias primas. Foi possível desenvolver novos SAB com LIs e proceder ao estudo e otimização dos mesmos na extração de cafeína e paracetamol. Por fim o processo otimizado foi aplicado a um resíduo medicamentoso (ALGIK). O resultado obtido demonstra uma completa extração dos compostos ativos com os SAB utilizados.
31
Mudarri, Timothy C. "A Novel Use for Ionic Polymer Transducers for Ionic Sensing in Liquid." Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/9671.
Abstract:
Ionic electroactive polymers have been developed as mechanical sensors or actuators, taking advantage of the electromechanical coupling of the materials. This research attempts to take advantage of the chemomechanical and chemoelectrical coupling by characterizing the transient response as the polymer undergoes an ion exchange, thus using the polymer for ionic sensing. Nafionâ ¢ is a biocompatible material, and an implantable polymeric ion sensor which has applications in the biomedical field for bone healing research. An ion sensor and a strain gauge could determine the effects of motion allowed at the fracture site, thus improving rehabilitation procedures for bone fractures.
The charge sensitivity of the material and the capacitance of the material were analyzed to determine the transient response. Both measures indicate a change when immersed in ionic salt solutions. It is demonstrated that measuring the capacitance is the best indicator of an ion exchange. Relative to a flat response in deionized water (±2%), the capacitance of the polymer exhibits an exponential decay of ~25% of its peak when placed in a salt solution. A linear correlation between the time constant of the decay and the ionic size of the exchanging ion was developed that could reasonably predict a diffusing ion. Tests using an energy dispersive spectrometer (EDS) indicate that 90% of the exchange occurs in the first 20 minutes, shown by both capacitance decay and an atomic level scan. The diffusion rate time constant was found to within 0.3% of the capacitance time constant, confirming the ability of capacitance to measure ion exchange.Master of Science
32
Gwee, Liang Elabd Yossef A. "Ion transport in polymer/ionic liquid films /." Philadelphia, Pa. : Drexel University, 2010. http://hdl.handle.net/1860/3268.
33
Gamstedt, Heléne. "Ionic Liquid Electrolytes for Photoelectrochemical Solar Cells." Doctoral thesis, KTH, Chemistry, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-426.
Abstract:
Potential electrolytes for dye-sensitized photoelectrochemical solar cells have been synthesized and their applicability has been investigated. Different experimental techniques were used in order to characterize the synthesized electrolytes, such as elemental analysis, electrospray ionisation/mass spectrometry, cyclic voltammetry, dynamic viscosity measurements, as well as impedance, Raman and NMR spectroscopy. Some crystal structures were characterized by using single crystal X-ray diffraction.
In order to verify the eligibility of the ionic compounds as electrolytes for photoelectrochemical solar cells, photocurrent density/photovoltage and incident photon-to-current conversion efficiency measurements were performed, using different kinds of light sources as solar simulators. In electron kinetic studies, the electron transport times in the solar cells were investigated by using intensitymodulated photocurrent and photovoltage spectroscopy. The accumulated charge present in the semiconductor was studied in photocurrent transient measurements.
The ionic liquids were successfully used as solar cell electrolytes, especially those originating from the diethyl and dibutyl-alkylsulphonium iodides. The highest overall conversion efficiency of almost 4 % was achieved by a dye-sensitized, nanocrystalline solar cell using (Bu2MeS)I:I2 (100:1) as electrolyte (Air Mass 1.5 spectrum at 100 W m-2), quite compatible with the standard efficiencies provided by organic solvent-containing cells. Several solar cells with iodine-doped metal-iodidebased electrolytes reached stable efficiencies over 2 %. The (Bu2MeS)I:I2-containing cells showed better long-term stabilities than the organic solvent-based cells, and provided the fastest electron transports as well as the highest charge accumulation.
Several polypyridyl-ruthenium complexes were tested as solar cell sensitizers. No general improvements could be observed according to the addition of amphiphilic co-adsorbents to the dyes or nanopartices of titanium dioxide to the electrolytes. For ionic liquid-containing solar cells, a saturation phenomena in the short-circuit current densities emerged at increased light intensities, probably due to inherent material transport limitation within the systems.
Some iodoargentates and -cuprates were structurally characterized, consisting of monomeric or polymeric entities with anionic networks or layers. A system of metal iodide crownether complexes were employed and tested as electrolytes in photoelectrochemical solar cells, though with poorer results. Also, the crystal structure of a copper-iodide-(12-crown-4) complex has been characterized
34
Gamstedt, Heléne. "Ionic liquid electrolytes for photoelectrochemical solar cells /." Stockholm, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-426.
35
Vaughan, James. "Ionic liquid electrochemical processing of reactive metals." Thesis, University of British Columbia, 2007. http://hdl.handle.net/2429/445.
Abstract:
Ionic liquids (ILs) were studied as solvents for electrochemical reactions with the intent to devise metallurgical processes for Al, Mg and Ti that are less energy intensive and operate at lower temperatures than current industrial practice. Tetra-alkyl phosphonium ILs are on the low end of the IL cost spectrum and are regarded as understudied compared with imidazolium and pyridinium ILs. They are also known to be more thermally stable.
The density, viscosity and conductivity of the phosphonium ILs and metal salt-IL mixtures were measured. The conductivity of the phosphonium ILs tested were found to be roughly an order of magnitude lower than imidazolium ILs; this is attributed to the relatively large cation size and localized charge. Linear density-temperature functions are presented. The viscosity and conductivity temperature relationship was modeled using the Vogel-Tamman-Fulcher (VTF) equation.
The electrochemical window of A10341'14,6,6,610 was studied on a Pt substrate over a wide range of A1C13 concentrations using cyclic voltammetry (CV). It was found that the tetra-alkyl phosphonium cation is on the order of 800 mV more electrochemically stable than the 1-ethyl-3-methyl imidazolium (EMI+).
Cathodic and anodic polarization of Al in A1C13-[P14,6,6,6]C1 (Xmc13 = 0.67) was studied at temperatures ranging from 347 to 423 K. The Butler-Volmer equation was fitted to the plots by varying the kinetic parameters. The cathodic reaction was found to be diffusion limited and the anodic reaction is limited by passivation at lower temperatures. The overpotential required for electrodissolution of Al was found to be higher than for electrodeposition.
Aluminium was electrodeposited using both an electrowinning setup (chlorine evolution anode reaction) and electrorefining setup (Al dissolution anode reaction). The deposits were characterized in terms of morphology, current efficiency and power consumption. A variety of deposit morphologies were observed ranging from smooth, to spherical to dendritic, and in some cases, the IL was occluded in the deposit. The current efficiency and power consumption were negatively impacted by the presence of H2O and HCl present in the as-received ILs and by C12(g) generated by the anode reaction in the case of the electrowinning setup. HC1 was removed by cyclic polarization or corrosion of pure Al, resulting in current efficiencies above 90%. Aluminium was electrodeposited using the electrorefining setup with anode-cathode spacing of 2 mm at power consumption as low as 0.6 kWhr/kg-Al. This is very low compared with industrial Al electrorefining and Al electroplating using the National Bureau of Standards bath, which require 15-18 kWhr/kg-Al and 18 kWhr/kg-Al, respectively. However, due to low solution conductivity the power consumption increases significantly with increased anode-cathode spacing.
Titanium tetrachloride was found to be soluble in [P14,6,6,6]Cl and increases the conductivity of the solution. Attempts to reduce the Ti(IV) included corrosion of titanium metal, corrosion of magnesium metal powder and cathodic polarization. Despite a few attempts, the electro-deposition of Ti was not observed. At this point, titanium electrodeposition from phosphonium based ILs does not appear feasible.
36
Styring, Peter. "Neutral and ionic metal-containing liquid crystals." Thesis, University of Sheffield, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.285012.
37
Oster, Kamil. "Ionic liquid-based nanofluids for thermal application." Thesis, University of Manchester, 2018. https://www.research.manchester.ac.uk/portal/en/theses/ionic-liquid--based-nanofluids-for-thermal-application(1039c799-bc2b-49b3-ba1d-dab27f607a2e).html.
Abstract:
Heat transfer fluids are materials responsible for heat distribution, transfer and storage. Their significance is undeniable - many technological processes cannot be carried out without using heat transfer materials (for example due to overheating). These are usually mixtures of many compounds, for example glycols, silicones or water. Today's technologies constantly require more efficient, environmentally- and economically-friendly solutions for heat transfer applications. It is necessary to know the full physicochemical characteristics to design a new heat transfer fluid (mainly density, heat capacity, viscosity and thermal conductivity). Nanofluids (mixture of a basefluid and nanoparticles) were proposed as a solution for many industrial issues due to their enhanced thermophysical properties (i.e. thermal conductivity) than pure liquids. Moreover, these enhancements exhibit unusual features which make this group of materials interesting from molecular and industrial point of view. Ionic liquids, task specific materials with tuneable properties were repeatedly recommended as heat transfer fluids due to their specific properties (mainly low vapour pressure, wide liquidus range, or non-flammability) caused by the ionic structure. A very interesting material can be obtained by mixing ionic liquids and nanoparticles where specific properties of ionic liquids are preserved, and thermophysical properties are enhanced due to nanoparticles dispersion. In this work, we investigated ionic liquid - based nanofluids from the experimental and theoretical point of view, including imidazolium-, pyrrolidinium- and phosphonium-based ionic liquids with several different anions, and multiwalled carbon nanotubes, graphite, boron nitride and mesoporous carbon as nanoparticles, and also in mixtures with water. As a final result, we assessed the molecular recognition of the thermophysical properties enhancements in ionanofluids, developed the predictive models for physical properties, compared all investigated systems to commercial heat transfer fluids. The project was supported by King Faisal University (Saudi Arabia) through a research fund from the International Cooperation and Knowledge Exchange Administration department at KFU. Cytec are thanked for the generous donation of the trihexyl(tetradecyl)phosphonium chloride sample.
38
Green, Stephen Mark. "Understanding ionic liquid properties for carbohydrate dissolution." Thesis, University of Leeds, 2017. http://etheses.whiterose.ac.uk/18123/.
Abstract:
The study of ionic liquids (ILs) is one of the fastest growing research fields today, both in academic and industrial spheres. One important use of ILs is in dissolving and processing biological resources, particularly cellulose. There is huge interest in understanding the properties of cellulose-dissolving ILs and how different IL features affect the dissolution environment. The work presented in this thesis is an experimental study into two classes of cellulose-dissolving ILs. Two distinct investigations are undertaken on pure ILs, first with imidazolium-carboxylate ILs and then with 1,5-diazabicyclo[4.3.0]non-5-enium (DBN) carboxylate ILs. A third investigation is then presented, examining solutions of glucose, cellobiose and cellulose in the imidazolium-based IL, 1-ethyl-3-methylimidazolium octanoate ([C2MIM][Oct]). Several NMR techniques are used, along with rheological, conductivity and density data. A novel modelling approach is formulated and then applied to the pure IL series', where simple systems of ion pairs and charged aggregates are considered, in order to accurately model several key experimental features. Four pure imidazolium-based ILs are studied with varying-length carboxylate anions. Microscopic properties, such as NMR data, are compared to macroscopic properties, such as viscosity. Stokes-Einstein-Debye theories are applied to the different datasets, providing an insight into the microscopic structuring in the different ILs. Nernst-Einstein theory and the Walden rule are also examined for these ILs. Inconsistencies between different datasets and theoretical expectations are addressed and several simple models are applied, in order to account for these inconsistencies. An ion pairing model, a charged aggregate model and a combination of both models are tested, indicating that this approach is reasonably successful in describing the imidazolium-based ILs and suggesting a small amount of ion aggregation is present. In a similar study, eight pure DBN-carboxylate ILs are studied, with systematically varying anion sizes between formate and octanoate. Experimental data are presented, indicating a complex dependence on anion chain length. Comparisons of micro- and macroscopic properties are shown, comparing and contrasting the effects of changing anion chain length and changing the cation. The three models of ion aggregation are successfully applied to the six room-temperature DBN-based ILs, indicating a higher degree of aggregation and ion pairing, as compared to the imidazolium-based ILs. Finally, [C2MIM][Oct] is investigated as a solvent for the carbohydrates glucose, cellobiose and cellulose. NMR and rheological data are presented and compared for carbohydrate solutions. Different NMR datasets are studied in-depth, including diffusion, relaxation and chemical shift. The carbohydrate-concentration dependence of each dataset is examined and compared to literature data for the same solutions in [C2MIM][Ac]. The relative time and length scales of the NMR techniques were found to affect how the solutions respond to increasing carbohydrate concentration and changing between glucose, cellobiose and cellulose. This thesis forms part of a project funded by the EPSRC CASE award with Innovia Films, aiming to better understand the process of cellulose dissolution in ILs. The results and techniques described here can aid in understanding the properties of these ILs, both for cellulose dissolution and other IL applications.
39
Kay, Nicola Julie. "Single molecule electronics in ionic liquid media." Thesis, University of Liverpool, 2012. http://livrepository.liverpool.ac.uk/6733/.
Abstract:
The field of single molecule electronics, where the charge transport properties of a variety of single molecular systems are investigated, has vastly increased in popularity over the last decade. This thesis in particular explores the single molecule conductance and electron transfer over a range of molecules in a room temperature ionic liquid medium. Prior to the work contained in this thesis, no conductance measurements of a single molecule had been recorded in a room temperature ionic liquid medium, to the best of our knowledge. Due to the novelty of room temperature ionic liquids in this field, it was decided that alkanedithiols would be an ideal starting point, largely due to their simplicity and reputation as a model system in single molecule electronics. Ionic liquids have several notable advantages as a medium in such measurements and the aim of the research contained in this thesis is first to show that ionic liquids are indeed a viable medium and secondly, to demonstrate their advantages over more widely used, conventional aqueous or organic media. The redox active molecular wire pyrrolo-tetrathiafulvalene is a particular molecule which would highlight the benefits of an ionic liquid medium, as it has a redox transition which is outside of the potential window available to aqueous electrolytes. Single molecule conductance measurements were obtained using a scanning tunnelling microscope (STM), in particular, the current-distance I(s) technique, and for alkanedithiols also the STM break junction technique. The electrochemistry of pyrrolo-tetrathiafulvalene was investigated using cyclic voltammetry and a monolayer of pyrrolo-tetrathiafulvalene was characterised using polarisation modulation infrared reflection absorption spectroscopy (PM-IRRAS).
40
Xu, Fei. "Ionic Liquid Crystals Based on Fluorocomplex Anions." Kyoto University, 2012. http://hdl.handle.net/2433/160955.
41
Zou, Yiran. "Gas separation using supported ionic liquid membranes." Thesis, Queen's University Belfast, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.517535.
42
Lazzari, Mariachiara <1978>. "Electrode Materials for Ionic Liquid Based-Supercapacitors." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2010. http://amsdottorato.unibo.it/2718/1/Lazzari_Mariachiara_Tesi.pdf.
Abstract:
The development of safe, high energy and power electrochemical energy-conversion systems can be a response to the worldwide demand for a clean and low-fuel-consuming transport. This thesis work, starting from a basic studies on the ionic liquid (IL) electrolytes and carbon electrodes and concluding with tests on large-size IL-based supercapacitor prototypes demonstrated that the IL-based asymmetric configuration (AEDLCs) is a powerful strategy to develop safe, high-energy supercapacitors that might compete with lithium-ion batteries in power assist-hybrid electric vehicles (HEVs). The increase of specific energy in EDLCs was achieved following three routes: i) the use of hydrophobic ionic liquids (ILs) as electrolytes; ii) the design and preparation of carbon electrode materials of tailored morphology and surface chemistry to feature high capacitance response in IL and iii) the asymmetric double-layer carbon supercapacitor configuration (AEDLC) which consists of assembling the supercapacitor with different carbon loadings at the two electrodes in order to exploit the wide electrochemical stability window (ESW) of IL and to reach high maximum cell voltage (Vmax).
Among the various ILs investigated the N-methoxyethyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PYR1(2O1)TFSI) was selected because of its hydrophobicity and high thermal stability up to 350 °C together with good conductivity and wide ESW, exploitable in a wide temperature range, below 0°C. For such exceptional properties PYR1(2O1)TFSI was used for the whole study to develop large size IL-based carbon supercapacitor prototype.
This work also highlights that the use of ILs determines different chemical-physical properties at the interface electrode/electrolyte with respect to that formed by conventional electrolytes. Indeed, the absence of solvent in ILs makes the properties of the interface not mediated by the solvent and, thus, the dielectric constant and double-layer thickness strictly depend on the chemistry of the IL ions.
The study of carbon electrode materials evidences several factors that have to be taken into account for designing performing carbon electrodes in IL. The heat-treatment in inert atmosphere of the activated carbon AC which gave ACT carbon featuring ca. 100 F/g in IL demonstrated the importance of surface chemistry in the capacitive response of the carbons in hydrophobic ILs. The tailored mesoporosity of the xerogel carbons is a key parameter to achieve high capacitance response. The CO2-treated xerogel carbon X3a featured a high specific capacitance of 120 F/g in PYR14TFSI, however, exhibiting high pore volume, an excess of IL is required to fill the pores with respect to that necessary for the charge-discharge process. Further advances were achieved with electrodes based on the disordered template carbon DTC7 with pore size distribution centred at 2.7 nm which featured a notably high specific capacitance of 140 F/g in PYR14TFSI and a moderate pore volume, V>1.5 nm of 0.70 cm3/g.
This thesis work demonstrated that by means of the asymmetric configuration (AEDLC) it was possible to reach high cell voltage up to 3.9 V. Indeed, IL-based AEDLCs with the X3a or ACT carbon electrodes exhibited specific energy and power of ca. 30 Wh/kg and 10 kW/kg, respectively. The DTC7 carbon electrodes, featuring a capacitance response higher of 20%-40% than those of X3a and ACT, respectively, enabled the development of a PYR14TFSI-based AEDLC with specific energy and power of 47 Wh/kg and 13 kW/kg at 60°C with Vmax of 3.9 V.
Given the availability of the ACT carbon (obtained from a commercial material), the PYR1(2O1)TFSI-based AEDLCs assembled with ACT carbon electrodes were selected within the EU ILHYPOS project for the development of large-size prototypes. This study demonstrated that PYR1(2O1)TFSI-based AEDLC can operate between -30°C and +60°C and its cycling stability was proved at 60°C up to 27,000 cycles with high Vmax up to 3.8 V. Such AEDLC was further investigated following USABC and DOE FreedomCAR reference protocols for HEV to evaluate its dynamic pulse-power and energy features. It was demonstrated that with Vmax of 3.7 V at T> 30 °C the challenging energy and power targets stated by DOE for power-assist HEVs, and at T> 0 °C the standards for the 12V-TSS and 42V-FSS and TPA 2s-pulse applications are satisfied, if the ratio wmodule/wSC = 2 is accomplished, which, however, is a very demanding condition.
Finally, suggestions for further advances in IL-based AEDLC performance were found. Particularly, given that the main contribution to the ESR is the electrode charging resistance, which in turn is affected by the ionic resistance in the pores that is also modulated by pore length, the pore geometry is a key parameter in carbon design not only because it defines the carbon surface but also because it can differentially “amplify” the effect of IL conductivity on the electrode charging-discharging process and, thus, supercapacitor time constant.
43
Lazzari, Mariachiara <1978>. "Electrode Materials for Ionic Liquid Based-Supercapacitors." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2010. http://amsdottorato.unibo.it/2718/.
Abstract:
The development of safe, high energy and power electrochemical energy-conversion systems can be a response to the worldwide demand for a clean and low-fuel-consuming transport. This thesis work, starting from a basic studies on the ionic liquid (IL) electrolytes and carbon electrodes and concluding with tests on large-size IL-based supercapacitor prototypes demonstrated that the IL-based asymmetric configuration (AEDLCs) is a powerful strategy to develop safe, high-energy supercapacitors that might compete with lithium-ion batteries in power assist-hybrid electric vehicles (HEVs). The increase of specific energy in EDLCs was achieved following three routes: i) the use of hydrophobic ionic liquids (ILs) as electrolytes; ii) the design and preparation of carbon electrode materials of tailored morphology and surface chemistry to feature high capacitance response in IL and iii) the asymmetric double-layer carbon supercapacitor configuration (AEDLC) which consists of assembling the supercapacitor with different carbon loadings at the two electrodes in order to exploit the wide electrochemical stability window (ESW) of IL and to reach high maximum cell voltage (Vmax).
Among the various ILs investigated the N-methoxyethyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PYR1(2O1)TFSI) was selected because of its hydrophobicity and high thermal stability up to 350 °C together with good conductivity and wide ESW, exploitable in a wide temperature range, below 0°C. For such exceptional properties PYR1(2O1)TFSI was used for the whole study to develop large size IL-based carbon supercapacitor prototype.
This work also highlights that the use of ILs determines different chemical-physical properties at the interface electrode/electrolyte with respect to that formed by conventional electrolytes. Indeed, the absence of solvent in ILs makes the properties of the interface not mediated by the solvent and, thus, the dielectric constant and double-layer thickness strictly depend on the chemistry of the IL ions.
The study of carbon electrode materials evidences several factors that have to be taken into account for designing performing carbon electrodes in IL. The heat-treatment in inert atmosphere of the activated carbon AC which gave ACT carbon featuring ca. 100 F/g in IL demonstrated the importance of surface chemistry in the capacitive response of the carbons in hydrophobic ILs. The tailored mesoporosity of the xerogel carbons is a key parameter to achieve high capacitance response. The CO2-treated xerogel carbon X3a featured a high specific capacitance of 120 F/g in PYR14TFSI, however, exhibiting high pore volume, an excess of IL is required to fill the pores with respect to that necessary for the charge-discharge process. Further advances were achieved with electrodes based on the disordered template carbon DTC7 with pore size distribution centred at 2.7 nm which featured a notably high specific capacitance of 140 F/g in PYR14TFSI and a moderate pore volume, V>1.5 nm of 0.70 cm3/g.
This thesis work demonstrated that by means of the asymmetric configuration (AEDLC) it was possible to reach high cell voltage up to 3.9 V. Indeed, IL-based AEDLCs with the X3a or ACT carbon electrodes exhibited specific energy and power of ca. 30 Wh/kg and 10 kW/kg, respectively. The DTC7 carbon electrodes, featuring a capacitance response higher of 20%-40% than those of X3a and ACT, respectively, enabled the development of a PYR14TFSI-based AEDLC with specific energy and power of 47 Wh/kg and 13 kW/kg at 60°C with Vmax of 3.9 V.
Given the availability of the ACT carbon (obtained from a commercial material), the PYR1(2O1)TFSI-based AEDLCs assembled with ACT carbon electrodes were selected within the EU ILHYPOS project for the development of large-size prototypes. This study demonstrated that PYR1(2O1)TFSI-based AEDLC can operate between -30°C and +60°C and its cycling stability was proved at 60°C up to 27,000 cycles with high Vmax up to 3.8 V. Such AEDLC was further investigated following USABC and DOE FreedomCAR reference protocols for HEV to evaluate its dynamic pulse-power and energy features. It was demonstrated that with Vmax of 3.7 V at T> 30 °C the challenging energy and power targets stated by DOE for power-assist HEVs, and at T> 0 °C the standards for the 12V-TSS and 42V-FSS and TPA 2s-pulse applications are satisfied, if the ratio wmodule/wSC = 2 is accomplished, which, however, is a very demanding condition.
Finally, suggestions for further advances in IL-based AEDLC performance were found. Particularly, given that the main contribution to the ESR is the electrode charging resistance, which in turn is affected by the ionic resistance in the pores that is also modulated by pore length, the pore geometry is a key parameter in carbon design not only because it defines the carbon surface but also because it can differentially “amplify” the effect of IL conductivity on the electrode charging-discharging process and, thus, supercapacitor time constant.
44
Nel, Jessica Lisé. "A computational study of acidic Ionic Liquids for cellobiose hydrolysis in ionic liquids." Master's thesis, Faculty of Science, 2019. https://hdl.handle.net/11427/31841.
Abstract:
The current environmental situation, with respect to global warming and the ever– approaching depletion of fossil fuel sources, places significance on the development of green fuel and platform chemical production methods. In this context, processes that utilise biomass sources as feedstock, are of great interest. Cellulose, which is the most abundant biopolymer in nature, is a renewable low–cost carbon resource derived from harvest residues and sources like wood and straw. Glucose generation from cellulose requires a saccharide conversion, whereby the β-(1,4)-glycosidic bond linkages in the cellobiose polymer repeating units are cleaved. Problems arise in the hydrolysis of cellulose as experimental and theoretical studies have shown cellulose to have very low solubility in water and most other general molecular solvents. This results in the use of harsh pretreatments at high temperatures and pressures to extract cellulose from lignocellulosic material and strong acids catalysts (pKa < −3.2). Room temperature ionic liquids (RTILs) provide potentially environmentally friendly alternative. It has been shown that ILs can dissolve cellulose under relatively benign conditions and can possibly be adapted into a one-pot-like process of hydrolysis using acid-functionalised IL catalysts. This dissertation investigated the effect of various ionic liquids on the thermodynamics of cellobiose acid hydrolysis, as both a catalyst and as a solvent, using computational means. An appropriate thermodynamic cycle protocol, a DLPNO-CCSD(T)/ccpVTZ//TPSS/def2-TZVP [M05-2X/6-31+G** (SMD)] proton exchange cycle, was established through benchmarking for the prediction of Brønsted acid-functionalised ionic liquid pKa values in ionic liquids. The sulfonyl-functionalised acidic IL was shown to be the most acidic IL resulting in a lower protonation free energy. Solvation in ionic liquids resulted in higher protonation and barrier height free energies relative to solvation in water. The current environmental situation, with respect to global warming and the ever– approaching depletion of fossil fuel sources, places significance on the development of green fuel and platform chemical production methods. In this context, processes that utilise biomass sources as feedstock, are of great interest. Cellulose, which is the most abundant biopolymer in nature, is a renewable low–cost carbon resource derived from harvest residues and sources like wood and straw. Glucose generation from cellulose requires a saccharide conversion, whereby the β-(1,4)-glycosidic bond linkages in the cellobiose polymer repeating units are cleaved. Problems arise in the hydrolysis of cellulose as experimental and theoretical studies have shown cellulose to have very low solubility in water and most other general molecular solvents. This results in the use of harsh pretreatments at high temperatures and pressures to extract cellulose from lignocellulosic material and strong acids catalysts (pKa < −3.2). Room temperature ionic liquids (RTILs) provide potentially environmentally friendly alternative. It has been shown that ILs can dissolve cellulose under relatively benign conditions and can possibly be adapted into a one-pot-like process of hydrolysis using acid-functionalised IL catalysts. This dissertation investigated the effect of various ionic liquids on the thermodynamics of cellobiose acid hydrolysis, as both a catalyst and as a solvent, using computational means. An appropriate thermodynamic cycle protocol, a DLPNO-CCSD(T)/ccpVTZ//TPSS/def2-TZVP [M05-2X/6-31+G** (SMD)] proton exchange cycle, was established through benchmarking for the prediction of Brønsted acid-functionalised ionic liquid pKa values in ionic liquids. The sulfonyl-functionalised acidic IL was shown to be the most acidic IL resulting in a lower protonation free energy. Solvation in ionic liquids resulted in higher protonation and barrier height free energies relative to solvation in water.
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Dotlich, Erin Michele. "ALKYLAMMONIUM FORMATE IONIC LIQUIDS AS SOLVENTS FOR FLUORESCENCE AND LIQUID CHROMATOGRAPHY METHODS." Miami University / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=miami1208983119.
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Traore, Youssouf. "Perspective nouvelle pour la récupération de l'indium issu des e-déchets par électrodéposition dans les liquides ioniques à température ambiante." Phd thesis, Université de Grenoble, 2012. http://tel.archives-ouvertes.fr/tel-00733947.
Abstract:
Face à une croissance effrénée de la demande en indium et aux enjeux à la fois socio-économiques et politiques potentiels qu'il représente, le recyclage de l'indium contenu dans les équipements en fin de vie reste la seule alternative pour remédier à des risques de pénuries. Au-delà des aspects économique et stratégique, le recyclage de l'indium peut permettre de préserver l'environnement en évitant l'exploitation à grande échelle des gisements de minerais contenant l'indium. Par ailleurs, la toxicité de l'indium justifie à elle seule le développement de procédés de traitement de déchets en contenant. Pourtant, la récupération de l'indium à partir de déchets électroniques est actuellement assez peu développée, mis à part au Japon, où plusieurs procédés existent à l'échelle industrielle. Ces procédés sont toutefois peu respectueux de l'environnement et fortement énergivores. Dans ce travail de doctorat, le recyclage de l'indium par extraction liquide/liquide dans un liquide ionique suivie de son électrodéposition in situ nous est apparu comme un procédé prometteur, permettant de s'affranchir de l'étape souvent difficile de dés-extraction du cation métallique. Parmi les liquides ioniques que nous avons synthétisés et caractérisés, en termes de structure et de propriétés physico-chimiques, le bis(trifluorométhylsulfonyl) amidure de 1-butyl-1-éthylpipéridinium (BEPipNTf2) s'est avéré le plus adapté du fait de sa bonne stabilité cathodique, de sa faible viscosité, de son caractère hydrophobe et peu hygroscopique. Nous avons montré qu'en synergie avec l'oxyde de trioctylphosphine (TOPO) comme extractant, il est possible d'extraire plus de 90% de l'indium contenu dans une phase aqueuse 10-2 M en HCl. Le système électrochimique In(III)/In(0) dans le BEPipNTf2 a alors été étudié en présence de chlorures, d'eau, d'oxygène et de TOPO, espèces présentes à l'issue de l'étape d'extraction liquide/liquide de l'In(III). Une étude détaillée de l'influence des ions chlorures a notamment été réalisée, mettant en évidence la formation de chlorocomplexes d'indium lors de l'application d'un potentiel cathodique de réduction de l'In(III), ce qui modifie considérablement les caractéristiques électrochimiques du système In(III)/In(0). Les résultats obtenus montrent qu'il est possible d'électrodéposer de l'In(III) sous sa forme métallique dans le domaine de stabilité électrochimique du liquide ionique, et ceci de façon non réversible en présence de TOPO, dont l'électroactivité dans le domaine de potentiel correspondant porte néanmoins à croire que la réduction pourrait entraîner la présence d'impuretés organiques dans le dépôt d'indium et limiter la quantité de métal déposée.
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Roy, Kanak. "Inclusion complexes and solvation consequences of ionic liquids and biologically active molecules in liquid systems." Thesis, University of North Bengal, 2017. http://ir.nbu.ac.in/handle/123456789/2587.
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Bastos, Pedro David Anastácio de. "Separation of azeotropic mixtures using high ionicity ionic liquids." Master's thesis, Faculdade de Ciências e Tecnologia, 2014. http://hdl.handle.net/10362/12208.
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Autenrieth, Benjamin [Verfasser], and Michael R. [Akademischer Betreuer] Buchmeiser. "Continuous metathesis under biphasic liquid-liquid conditions using monolith-supported ionic liquids / Benjamin Autenrieth. Betreuer: Michael R. Buchmeiser." Stuttgart : Universitätsbibliothek der Universität Stuttgart, 2013. http://d-nb.info/1043957944/34.
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Zahrtmann, Nanette. "Pd-catalysed Carbonylations of Anilines in Ionic Liquid." Doctoral thesis, Universitat Rovira i Virgili, 2017. http://hdl.handle.net/10803/450855.
Abstract:
Aquesta tesi descriu l'estudi de diversos catalitzadors de pal·ladi amb lligands donants de fòsfor i nitrogen disponibles
al mercat, ja sigui com l'únic lligant o en combinació amb carbens N-heterocíclics. Els sistemes de pal·ladi es van
aplicar en carbonilació de anilines per a la formació d'amides i urees. La tesi es divideix en quatre capítols. El primer
capítol és una breu introducció a la chemisty carbonilació de catalitzadors de pal·ladi homogenis. També es discuteix
reaccions de carbonilació impliquen líquids iònics i catalitzadors SILP. El segon capítol tracta de la formació d'amides
a partir d'anilines. Un nou sistema catalític es descriu i es proposa un mecanisme. El tercer capítol es refereix l'estudi
de dos sistemes catalítics per a la formació d'urea de difenil implica líquids iònics com a facilitador dissolvent i la
reacció. El quart capítol s'ocupa de la transferència del líquid intervinguda per carbonilació oxidativa iònica d'anilina en
el flux. Recolzat tecnologia fase líquida iònica es va aplicar per a la heterogeneïtzació del catalitzador molecular.Esta tesis describe el estudio de varios catalizadores de paladio con ligandos de fósforo y nitrógeno comercialmente disponibles, ya sea como único ligando o en combinación con carbenos N-heterocíclicos. Los sistemas de paladio se aplicaron en la carbonilación de anilinas para la formación de amidas y ureas. La tesis se divide en cuatro capítulos. El primer capítulo es una breve introducción a la química de la carbonilación de catalizadores homogéneos de paladio. También se discuten reacciones de carbonilación que involucran líquidos iónicos y catalizadores SILP. El segundo capítulo trata de la formación de amidas a partir de anilinas. Se describe un nuevo sistema catalítico y se propone un mecanismo. El tercer capítulo abarca el estudio de dos sistemas catalíticos para la formación de difenil urea, y que implica líquidos iónicos como disolvente y facilitador de la reacción. El cuarto capítulo describe la transferencia de la carbonilación oxidativa mediada por líquido iónico de la anilina en el flujo. Se aplicó tecnología de fase líquido iónico soportada para la heterogeneización del catalizador molecular.
This thesis describes the study of several palladium catalysts with commercially available phosphorus and nitrogen donor ligands, either as sole ligand or in combination with N-heterocyclic carbenes. The palladium systems were applied in carbonylation of anilines for the formation of amides and ureas. The thesis is divided into four chapters. The first chapter is a brief introduction to the carbonylation chemisty of homogeneous palladium catalysts. Carbonylation reactions involving ionic liquids and SILP catalysts is also discussed. The second chapter deals with the formation of amides from anilines. A novel catalytic system is disclosed and a mechanism is proposed. The third chapter covers the study of two catalytic systems for the formation of diphenyl urea involving ionic liquids as solvent and reaction facilitator. The fourth chapter describes the transfer of the ionic liquid mediated oxidative carbonylation of aniline into flow. Supported ionic liquid phase technology was applied for the heterogenization of the molecular catalyst.