Teses / dissertações sobre o tema "Ionic-Molecular systems"
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Tangney, Paul. "Improving molecular-dynamics simulations of simple ionic systems". Doctoral thesis, SISSA, 2002. http://hdl.handle.net/20.500.11767/3940.
Martinez, N. C. Forero. "Molecular models for protic ionic liquids and related systems". Thesis, Queen's University Belfast, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.557414.
Reid, Joshua Elias Samuel James. "Molecular thermodynamics and solvation behaviour of protic ionic liquid systems". Thesis, University of York, 2017. http://etheses.whiterose.ac.uk/18697/.
Guo, Zhenrong. "Characterization of ionic, dipolar and molecular mobility in polymer systems". W&M ScholarWorks, 2005. https://scholarworks.wm.edu/etd/1539623474.
McDonald, Anthony Michael. "Molecular dynamics simulation of ionic systems with large numbers of particles". Thesis, Keele University, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315233.
Carvalho, Sara Ferreira. "Aqueous biphasic systems composed of ionic liquids and polysaccharides". Master's thesis, Universidade de Aveiro, 2013. http://hdl.handle.net/10773/12600.
Aiming at finding more biocompatible and environmentally-benign separation processes, aqueous biphasic systems composed of ionic liquids can be envisaged as an alternative and advantageous approach for the extraction and purification of the most diverse biomolecules. In this work, the main goal consisted on the study of the ability of polysaccharides, as a benign alternative over inorganic salts typically used, to form aqueous biphasic systems with ionic liquids. To this aim, the phase diagrams and respective compositions of the two phases in equilibrium for ternary systems consisting of several ionic liquids, water, and polysaccharides were determined at 298 K. By the combination of different families of ionic liquids, achieved by a representative variety of cations and anions, with dextrans and maltodextrins, it was possible to infer on the effect of the IL structural characteristics, as well as on the polysaccharides molecular weight through the formation ability of aqueous two-phase systems. Finally, and to ascertain on the potential application of these new systems such as extraction techniques, some of them were also used and evaluated regarding their aptitude to extract amino acids. The use of polysaccharides, namely dextran and maltodextrin, as salting-out molecules to form aqueous biphasic systems with ionic liquids was the main focus of this work. It was demonstrated here, for the first time, that a new class of aqueous biphasic systems composed of ionic liquids and polysaccharides can be formed while contributing to the development of more efficient and sustainable separation and purification techniques. These systems can be also seen as promising routes in the improvement of biotechnological processes which increasingly tend to be decisive in industry.
No âmbito da procura de processos de separação mais biocompatíveis e amigos do ambiente, os sistemas aquosos bifásicos com líquidos iónicos constituem uma abordagem alternativa e vantajosa para a extração e purificação das mais diversas biomoléculas. Neste trabalho pretendeu-se estudar especificamente a capacidade de polissacarídeos, como uma alternativa mais benigna face aos sais normalmente utilizados, para formar sistemas aquosos bifásicos com líquidos iónicos. Para tal, determinaram-se os diagramas de fase e composições das duas fases em equilíbrio para diversos sistemas ternários formados por líquidos iónicos, água e polissacarídeos a 298 K. O estudo destes novos sistemas, combinando diferentes famílias de líquidos iónicos representados por uma variedade alargada de catiões e aniões, com dextranas e maltodextrinas, permitiu avaliar o efeito das características estruturais dos líquidos iónicos, bem como da massa molecular dos polissacarídeos, na capacidade de formação de sistemas de duas fases aquosas. Por fim, e para suportar a sua aplicação como novas técnicas de extração, alguns destes sistemas foram também avaliados no que respeita à sua capacidade para extrair aminoácidos. A utilização de polissacarídeos, nomeadamente de dextrano e maltodextrina, enquanto moléculas indutoras de salting-out para formar sistemas aquosos bifásicos com líquidos iónicos, constituiu o foco principal deste trabalho. Pela primeira vez foi mostrado que existe uma nova classe de sistemas aquosos bifásicos constituídos por líquidos iónicos e polissacarídeos contribuindo assim para o desenvolvimento de técnicas de separação e purificação de uma forma mais eficiente, sustentável e ecológica. Estes sistemas poderão ainda ser vistos como vias promissoras no melhoramento de processos biotecnológicos que tendem a ser cada vez mais decisivos na indústria.
Zhang, Fei. "Adsorption of Small Molecules in Advanced Material Systems". Diss., Virginia Tech, 2019. http://hdl.handle.net/10919/89917.
Doctor of Philosophy
Adsorption is a ubiquitous phenomenon that plays key roles in numerous applications including molecule separation, energy storage, catalysis, and lubrications. Since adsorption is sensitive to molecular details of adsorbate molecule and adsorbent materials, it is often difficult to describe theoretically. Molecular modeling capable of resolving physical processes at atomistic scales is an effective method for studying adsorption. In this dissertation, the adsorption of small molecules in three emerging materials systems: porous liquids, room-temperature ionic liquids, and atomically sharp electrodes immersed in aqueous electrolytes, are investigated to understand the physics of adsorption as well as to help design and optimize these materials systems. Thermodynamics and kinetics of gas storage in the recently synthesized porous liquids (crown-ether-substituted cage molecules dispersed in an organic solvent) were studied. Gas molecules were found to store differently in cage molecules with gas storage capacity per cage in the following order: CO2>CH4>N2. The cage molecules show selectivity of CO2 over CH4/N2 and demonstrate capability in gas separation. These studies suggest that porous liquids can be useful for CO2 capture from power plants and CH4 separation from shale gas. The effect of adsorbed water on the three-dimensional structure of ionic liquids [BMIM][Tf2N] near mica surfaces was investigated. It was shown that water, as a dielectric solvent and a molecular liquid, can alter layering and ordering of ions near mica surfaces. vi A three-way coupling between the self-organization of ions, the adsorption of interfacial water, and the electrification of the solid surfaces was suggested to govern the structure of ionic liquid near solid surfaces. The effects of electrode charge and surface curvature on adsorption of N2 molecules near electrodes immersed in water were studied. N2 molecules are enriched near neutral electrodes. Their enrichment is enhanced as the electrode becomes moderately charged but is reduced when the electrode becomes highly charged. Near highly charged electrodes, the amount of N2 molecules available for electrochemical reduction is an order of magnitude higher near spherical electrodes with radius ~1nm than near planar electrodes. The underlying molecular mechanisms are elucidated and their implications for development of electrodes for electrochemical reduction of N2 are discussed.
Dudariev, Dmytro. "Compétition entre la solvatation et l'agrégation ionique dans des systèmes ioniques-solvant : influence sur les propriétés de transport". Electronic Thesis or Diss., Université de Lille (2022-....), 2023. http://www.theses.fr/2023ULILR009.
The objective of this thesis is to analyze the microscopic structure of the series ion-molecular systems that widely used for practical electrochemistry and to characterize the effect of the ion aggregation on the transport properties of these systems. By using molecular dynamics simulation, the following systems were investigated: (i) the solutions of LiPF6 in dimethyl carbonate / ethylene carbonate mixture (1:1), (ii) the solutions of SBPBF4 in acetonitrile, and (iii) the mixtures of room-temperature ionic liquids (ILs) C4mimX (X= BF4-, PF6-, TFO-, TFSI-) with dipolar aprotic solvents such as acetonitrile, γ-butyrolactone and propylene carbonate.For all the systems the aggregate analysis showed the formation of the ionic continuous network with the increase of electrolyte concentration. This affects significantly diffusivity and viscosity in these solutions.Voronoi polyhedra analysis of ILs-solvent mixtures showed that below the IL mole fraction of about 0.2, the ions are well solvated by the solvent molecules, but above this mole fraction they start to form contact pairs, while the solvent molecules, expelled from the vicinity of the ions, self-associates
Wilson, Mark. "Many-body effects in ionic systems". Thesis, University of Oxford, 1994. http://ora.ox.ac.uk/objects/uuid:3c66daa2-5318-40d2-a445-15296d598a57.
Tu, Kai-Ming. "Spatial-Decomposition Analysis of Electrical Conductivity in Concentrated Ionic Systems". 京都大学 (Kyoto University), 2015. http://hdl.handle.net/2433/199125.
Shrivastav, Gourav. "Molecular dynamics studies of complex systems : molecular chain and ionic liquids". Thesis, 2018. http://localhost:8080/iit/handle/2074/7624.
Wojnarowska, Z., Krzysztof J. Paluch, E. Shoifet, C. Schick, L. Tajber, J. Knapik, P. Wlodarczyk et al. "Molecular origin of enhanced proton conductivity in anhydrous ionic systems". 2014. http://hdl.handle.net/10454/9420.
Ionic systems with enhanced proton conductivity are widely viewed as promising electrolytes in fuel cells and batteries. Nevertheless, a major challenge toward their commercial applications is determination of the factors controlling the fast proton hopping in anhydrous conditions. To address this issue, we have studied novel proton-conducting materials formed via a chemical reaction of lidocaine base with a series of acids characterized by a various number of proton-active sites. From ambient and high pressure experimental data, we have found that there are fundamental differences in the conducting properties of the examined salts. On the other hand, DFT calculations revealed that the internal proton hopping within the cation structure strongly affects the pathways of mobility of the charge carrier. These findings offer a fresh look on the Grotthuss-type mechanism in protic ionic glasses as well as provide new ideas for the design of anhydrous materials with exceptionally high proton conductivity.
"Ionic Liquid/Water/Particle Systems: Fundamentals Through Experiment, Application and Simulation". Doctoral diss., 2016. http://hdl.handle.net/2286/R.I.40797.
Dissertation/Thesis
Doctoral Dissertation Chemical Engineering 2016
Bahadur, Indra. "Excess molar volume and isentropic compressibility for binary or ternary ionic liquid systems". Thesis, 2010. http://hdl.handle.net/10321/559.
The thermodynamic properties of mixtures involving ionic liquids (ILs) with alcohols or alkyl acetate or nitromethane at different temperatures were determined. The ILs used were methyl trioctylammonium bis(trifluoromethylsulfonyl)imide ([MOA]+[Tf2N]-) and 1-butyl-3- methylimidazolium methyl sulphate [BMIM]+[MeSO4]-. The ternary excess molar volumes ( E ) for the mixtures {methyl trioctylammonium bis (trifluoromethylsulfonyl)imide + methanol or ethanol + methyl acetate or ethyl acetate}and (1- butyl-3-methylimidazolium methylsulfate + methanol or ethanol or 1-propanol + nitromethane) were calculated from experimental density values, at T = (298.15, 303.15 and 313.15) K and T = 298.15, respectively. The Cibulka equation was used to correlate the ternary excess molar volume data using binary data from literature. The E values for both IL ternary systems were negative at each temperature. The negative contribution of E values are due to the packing effect and/or strong intermolecular interactions (ion-dipole) between the different molecules. The density and speed of sound of the binary solutions ([MOA]+[Tf2N]- + methyl acetate or ethyl acetate or methanol or ethanol), (methanol + methyl acetate or ethyl acetate) and (ethanol + methyl acetate or ethyl acetate) were also measured at T = ( 298.15, 303.15, 308.15 and 313.15) K and at atmospheric pressure. The apparent molar volume, Vφ , and the apparent molar isentropic compressibility, κφ , were evaluated from the experimental density and speed of sound data. A Redlich-Mayer type equation was fitted to the apparent molar volume and apparent molar isentropic compressibility data. The results are discussed in terms of solute-solute, solute- solvent and solvent-solvent interactions. The apparent molar volume and apparent molar isentropic compressibility at infinite dilution, φ and κφ , respectively of the binary solutions have been calculated at each temperature. The φ values for the binary v systems ([MOA]+[Tf2N]- + methyl acetate or ethyl acetate or methanol or ethanol) and (methanol + methyl acetate or ethyl acetate) and (ethanol + methyl acetate or ethyl acetate) are positive and increase with an increase in temperature. For the (methanol + methyl acetate or ethyl acetate) systems φ values indicate that the (ion-solvent) interactions are weaker. The κφ is both positive and negative. Positive κφ , for ([MOA] + [Tf2N]- + ethyl acetate or ethanol), (methanol + ethyl acetate) and (ethanol + methyl acetate or ethyl acetate) can be attributed to the predominance of solvent intrinsic compressibility effect over the effect of penetration of ions of IL or methanol or ethanol. The positive κφ values can be interpreted in terms of increase in the compressibility of the solution compared to the pure solvent methyl acetate or ethyl acetate or ethanol. The κφ values increase with an increase in temperature. Negative κφ , for ([MOA] + [Tf2N]- + methyl acetate or methanol), and (methanol + methyl acetate) can be attributed to the predominance of penetration effect of solvent molecules into the intra-ionic free space of IL or methanol molecules over the effect of their solvent intrinsic compressibility. Negative κφ indicate that the solvent surrounding the IL or methanol would present greater resistance to compression than the bulk solvent. The κφ values decrease with an increase in the temperature. The infinite dilution apparent molar expansibility, φ , values for the binary systems (IL + methyl acetate or ethyl acetate or methanol or ethanol) and (methanol + methyl acetate or ethyl acetate) and (ethanol + methyl acetate or ethyl acetate) are positive and decrease with an increase in temperature due to the solution volume increasing less rapidly than the pure solvent. For (IL + methyl acetate or ethyl acetate or methanol or ethanol) systems φ indicates that the interaction between (IL + methyl acetate) is stronger than that of the (IL + ethanol) or (IL + methanol) or (IL + ethyl acetate) solution. For the (methanol + methyl acetate or ethyl acetate) systems φ values vi indicate that the interactions are stronger than (ethanol + methyl acetate or ethyl acetate) systems.
Sibiya, Precious N. "Excess molar volumes, partial molar volumes and isentropic compressibilities of binary systems (ionic liquid + alkanol)". Thesis, 2009. http://hdl.handle.net/10321/459.
The thermodynamic properties of binary liquid mixtures involving ionic liquids (ILs) with alcohols were determined. ILs are an important class of solvents since they are being investigated as environmentally benign solvents, because of their negligible vapour pressure, and as potential replacement solvents for volatile organic compounds (VOCs) currently used in industries. Alcohols were chosen for this study because they have hydrogen bonding and their interaction with ILs will help in understanding the intermolecular interactions. Also, their thermodynamic properties are used for the development of specific chemical processes. The excess molar volumes of binary mixtures of {1-ethyl-3-methylimidazolium ethylsulfate + methanol or 1-propanol or 2-propanol}, {trioctylmethylammonium bis (trifluoromethyl-sulfonyl) imide + methanol or ethanol or 1-propanol}, {1-buty-3-methylimidazolium methylsulfate + methanol or ethanol or 1-propanol} were calculated from experimental density values, at T = (298.15, 303.15 and 313.15) K. The Redlich-Kister smoothing polynomial was fitted to the excess molar volume data. The partial molar volumes of the binary mixtures {1-ethyl-3-methylimidazolium ethylsulfate + methanol or 1-propanol or 2-propanol}, {trioctylmethylammonium bis (trifluoromethyl-sulfonyl) imide + methanol or ethanol or 1-propanol}, {1-buty-3-methylimidazolium methylsulfate + methanol or ethanol or 1-propanol} were calculated from the Redlich-Kister coefficients, at T = (298.15, 303.15 and 313.15) K. This information was used to better understand the intermolecular interactions with each solvent at infinite dilution. iii The isentropic compressibility of {trioctylmethylammonium bis (trifluoromethyl-sulfonyl) imide + methanol or ethanol or 1-propanol}, were calculated from the speed of sound data at T = 298.15 K.
Chou, Dong-Han, e 周東和. "Studies on the thermal dynamic properties, bonding behavior and structure of water and ionic aqueous systems: A molecular dynamics simulation study". Thesis, 2007. http://ndltd.ncl.edu.tw/handle/25322465675175486460.
國立交通大學
應用化學系所
95
This study investigates on obtaining a water model suited to long simulation time of macromolecules in solution and constructing a simulation system of aqueous solutions. Comparison between other models revealed that flexible three-center model has been already used in many large-scale simulation and it’s provided with experimental data. Because the model works well with short-range truncation suited to high-speed computation. It’s tested by comparing the structural, dynamic and thermodynamic properties of water in aqueous solution, at several temperature and density, with the other models and experimental data. Our program also was tested by calculation such properties and fitted these literature very well. Therefore, the aims of research divide into three parts: First is tested for many water properties comparing with literature;Second investigates on the structural and dynamic properties of brine solutions;the other simulates charged aqueous nanodroplets for different condition, which were different temperatures, the number of ions, the type of ion and the size of droplets, in vacuum and these nanodroplets were given some additional velocity ranging from 1 m/s to 200 m/s to observe two nanodroplets bumped into or merged each other or merged . Studies show that ionic solvation shell effects strongly on the water structure in aqueous solution, like Cl- anion makes water more slow meaning ionic solvation shells are rigid. Computation of Bond time correlation functions shows that Cl--water pair can hold longer than water-water pair. The rigidity can play an important role in charged aqueous nanodroplets. At several conditions, the nanodroplet including Cl- ions were stable. Giving two nanodroplets a velocity in a direction to overcome the surface energy of the droplet made a formation of bridge structure and giving more kinetic energy performed the merged process. To calculate the surface area and volume of a nanodroplet, there are the merged nanodroplet and a nanodroplet had the same number water molecules and ions of the merged nanodroplet, we use the molecular modeling software TINKER implemented the algorithms of solvent accessible surface. The result of computation can prove the merged nanodroplet is the stable structure.
Bastos, Henrique Xavier Santos. "Towards an understanding of biomolecule partition in amphiphilic systems: development of a molecular dynamics framework". Master's thesis, 2019. http://hdl.handle.net/10773/30274.
As moléculas anfifílicas são elementos de elevado potencial de estruturas auto-organizadas para vários fins biotecnológicos, devido às suas componentes hidrofóbica e hidrofílica. Parte destas são biocompatíveis, capazes de transportar biomoléculas e altamente ajustáveis e controláveis por fatores externos. Estas propriedades são particularmente relevantes em aplicações de libertação controlada de fármacos. Os líquidos iónicos são cada vez mais utilizados desde a descoberta da sua sensibilidade a estímulos, ajustabilidade e possível uso como alternativas sustentáveis a solventes convencionais. Este trabalho teve como objetivo utilizar dinâmica molecular para estudar líquidos iónicos à base de iões amónio para extração e libertação de biomoléculas, particularmente ácido gálico ou ibuprofeno. Foi utilizada uma estratégia de simulação em várias escalas com o pacote de simulação em dinâmica molecular clássica GROMACS, onde modelos com alta resolução foram usados para criar modelos de grão-grosso novos, mais eficientes em estudos de partição e comportamento de fases. Foi averiguada a partição de ácido gálico e ibuprofeno nas soluções de líquido iónico em questão, bem como a orientação da biomolécula na estrutura supramolecular do líquido iónico e as interações que levaram à mesma. Foi verificado um efeito à base do pH como o principal fator a afetar os sistemas estudados. Este trabalho tem o potencial de dar origem a uma plataforma transversal e transferível para analisar e testar várias combinações de biomoléculas e líquidos iónicos em soluções aquosas de forma a poupar tempo e recursos experimentais em diversas aplicações.
Mestrado em Biotecnologia
Wu, Long Shing, e 吳龍興. "Theorical Study of Intermolecular and Inter-Ionic molecular Hydrogen Bonding in Amines Comparing System". Thesis, 2003. http://ndltd.ncl.edu.tw/handle/52093114401543887101.
國防大學中正理工學院
應用化學研究所
91
In this article we studied the amines (N(CH3)nH3-n) combined with different kinds of molecule to create the intermolecular hydrogen bonding and inter-ionic hydrogen bonding complex, from that way, discussing the influence of molecular structure stability by two kinds of hydrogen bonding systems. In the intermolecular hydrogen bonding system, we chosen amines combined with nitric acid (HNO3) or hydrogen halide (HX,X=F, Cl or Br) complex, to compare and analyze the affect of hydrogen bonding by methyl group and steric effect. However, in the part of ionic-inter hydrogen bonding, selected the amines combined with hydrogen halide complex for researching object, to discuss the distinction of intermolecular hydrogen bonding and inter-ionic hydrogen bonding. As the result of calculation, we found that methyl group really could strength the stability at intermolecular hydrogen bonding. Along with the addition of temperature because of steric effect and entropy, the stability sequence of Gibbs free energy (△G) would have different variations. In the amines combined with hydrogen halide complex, when methyl group added gradually and atomic number of halogen atom became augmented (Cl or Br), contrasted the migration of hydrogen atom position in hydrogen bonding system, we could find the tendency of total system transferred from intermolecular hydrogen bonding to inter-ionic hydrogen bonding. In the case of inter-ionic hydrogen bonding system, its binding energy between ions including both the coulombic attraction energy and hydrogen bonding energy. In this system, the overall energy between this ionic pairs is decreased whenever the number of CH3 is increasing due to proton accept or electron donor effect of methyl group.
Varanasi, Srinivasa Rao. "Relationship Between Pressure And Size Dependence Of Ionic Conductivity In Aqueous Solutions And Other Studies". Thesis, 2011. https://etd.iisc.ac.in/handle/2005/2183.
Varanasi, Srinivasa Rao. "Relationship Between Pressure And Size Dependence Of Ionic Conductivity In Aqueous Solutions And Other Studies". Thesis, 2011. http://etd.iisc.ernet.in/handle/2005/2183.