Vinyltrialkoxysilanes are grafted onto polyolefins via a radical mechanism; in a subsequent step, the pendant alkoxysilanes hydrolyze and condense upon exposure to water, resulting formation of crosslinks. Straight chain hydrocarbons were used as model compounds to investigate the regioselectivity of vinyltrimethoxysilane grafting. To stabilize the water-sensitive grafted products, the methoxy groups were substituted using phenyllithium. It was found that this reaction must be carried out for a minimum of three days to ensure full substitution. The grafted products were then separated on a weight basis using semi-preparative HPLC. Analysis of the di-grafted fraction using edited HSQC and HSQC-TOCSY NMR showed that radical propagation occurs via 1,4- and 1,5-intramolecular hydrogen shifts along the hydrocarbon backbone, resulting in multiple grafts per backbone. Post-combustion carbon capture targets CO₂ emissions from large point sources for capture and sequestration. A new class of potential carbon capture agents known as reversible ionic liquids (RevILs) has been synthesized and evaluated in terms of potential performance parameters (e.g. CO₂ capacity, viscosity, enthalpy of regeneration). These RevILs are silylated amines, which react with CO₂ to form a salt comprising an ammonium cation and a carbamate anion that is liquid at room temperature. Structural modifications of the basic silylamine skeleton result in drastic differences in the performance of the resulting RevIL. Systematic variation of the silylated amines allowed determination of a structure-property relationship, and continued iterations will allow development of an ideal candidate for scale-up. The properties and potential applications of gold nanoparticles (AuNP) are highly dependent on their size and shape. These properties are commonly controlled during liquid-phase synthesis through the use of capping agents, which must be removed following synthesis. Reverse micelles can also be used to control the morphology of AuNP during their synthesis. When RevILs are used in the formation of these reverse micelles, either as the disperse phase or as the surfactant, the built-in switch can be used to release the nanoparticles following their synthesis. This release on command could decrease the post-synthetic steps required to clean and purify AuNP prior to use. We have successfully synthesized AuNP using a number of different RevILs.

There is a continuing interest in the subject of arene carbonylation, especially in strong acids and environmentally-benign alternatives are sought to HF/BF3 and to AlCl3 as conversion agents. Ionic liquids offer a powerful solvent for useful conversion agents such as aluminum chloride. The ILs permit AlCl3 to be used at lower HCl partial pressures than with other solvents. The superior reactivity demonstrated by acidic, chloroaluminate ILs is probably due to their enhanced solvation power for HCl and CO. Addition of HCl gas increased reactivity of the system by forming Brnsted acids, and toluene carbonylation is a Brnsted demanding reaction. It was found that reaction is stoichiometric in Al species and only intrinsically acidic ILs are active for toluene carbonylation, therefore it was possible to correlate observed conversion with predicted amounts of Lewis + Brnsted acids. Molecular modeling provided information about the different species present in these ILs and predicted 1H NMR, and 27Al NMR spectrum. Predictions suggested that three types of HCl species are present; and these predictions were confirmed using data of 13C-labeled acetone and its 13C-NMR spectra. These data showed that only one of the three types of HCl in the IL were super acidic. Reactivity towards arene formylation can be tuned by adjusting the ligands R and R in the organic cation and by changing the anion. This reactivity tuning can be exploited in a process where high acidity is required for the conversion of substrate but where separation of product from IL is facilitated by low acidity.

Durant les darreres dècades, el disseny de processos en el marc de la química sostenible ha anat creixent de forma exponencial. La recerca constant de processos mes benignes amb el medi ambient ha implicat un gran esforç per obtenir millors rendiments mitjançant l'activació de llocs específics, i possant especial èmfasi amb el control de la quimio-, la regio- i la enantioselectivitat, punts crucials per a l'economia atómica. En aquest sentit, els dissolvents juguen un paper crític, i com podrà veure's al llarg d'aquesta memòria..Aquesta Tesi s'enfoca en l'ús de mitjans de reacció alternatius i sostenibles, com són els líquids iònics (ILs), el diòxid de carboni supercrític (scCO2) i la barreja de ambdós dissolvents, amb l'objectiu de disminuir l'ús de dissolvents orgànics convencionals i la seva aplicació en els següents processos catalítics: hidrogenació asimètrica, reacció de Suzuki d'acoblament creuat C-C, reacció d'alquilació al·lílica asimètrica i la hidrogenació de arens. / In the last decades, the design of processes in the framework of the sustainable chemistry has been exponentially growing. The constant searching of cleaner processes has led to a lot of effort to obtain higher yields by activation of specific sites, and improving chemo-, regio- and enantio-selectivities, which are crucial from a point of view of an atom economy strategy. In this sense, solvents play a critical role. This PhD thesis focuses on the use of alternative sustainable reaction media such as ionic liquids (ILs), supercritical carbon dioxide (scCO2) and mixtures of both solvents in different catalytic processes, with the aim of decreasing the use of conventional organic solvents applied in the following catalytic reactions: homogeneous and supported rhodium catalysed asymmetric hydrogenation, biphasic palladium catalysed Suzuki C-C cross-coupling, homogeneous palladium catalysed asymmetric allylic alkylation, and ruthenium and rhodium nanoparticles catalysed arene hydrogenation were tested.

The application of current soy protein films are limited due to their low mechanical strength and high moisture sensitivity compared to synthetic materials. This research studied several methods to improve the mechanical properties [tensile strength (TS), elongation at break (EAB), Young’s modulus of elasticity (YM)] of solvent cast soy protein isolate (SPI) films. Drying times were significantly reduced through the use of a heated casting surface. Neutral (pH 7) SPI films were prepared but were found to have lower TS, EAB and YM than control films prepared under alkaline conditions. Cellulose was extracted from soybean wastes and transmission electron microscopy (TEM) verified the existence of nano-sized fibres. Composite SPI films were prepared using either extracted cellulose fibres or titanium dioxide (TiO2) nanoparticles and their mechanical and barrier properties (water vapour, and oxygen permeability) were evaluated under different relative humidity (RH) conditions. In general, TS and YM decreased and EAB increased with increasing RH. Films with 5% (w/w) added cellulose exhibited significant (p-value < 0.05) improvements in TS and YM but decreased EAB. TiO2 composites possessed similar TS, YM, and EAB values to control films. Barrier properties were comparable across all samples, and decreased with increasing RH. Samples were characterized using Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and atomic force microscopy (AFM). Preliminary work investigating synthesis of filler materials using cross-linked sodium alginate particles increased the TS and YM of SPI films to a similar extent as extracted cellulose. A method for electrospinning cellulose using ionic liquids was developed, but requires further process optimization to be used for fibre/filler synthesis. / OMAFRA; Hannam Soy Utilization Fund

In the last decade there has been increasing research interest in the value of bio-sourced materials from lignocellulosic biomass. The dissolution of cellulose by ionic liquids (ILs) has led to investigations including the dissolution of cellulose, lignin, and complete biomass samples and the in situ processing of cellulose. Rapid quantitative measurement of cellulose dissolution in ILs is difficult. In this work, Fourier transform infrared spectroscopy (FTIR) spectra of cellulose dissolved in 1-ethyl-3-methylimidazolium acetate ([emim][OAc]) were subjected to partial least squares (PLS) regression to model dissolved cellulose content. PLS regression was used due to the ease in developing predictive models with this technique in addition to linear regression being ineffectual for modeling when applied to potentially thousands of variables. Applying a normalization data treatment, before regression, generated a model that estimated cellulose content within 0.533 wt%. The methods described provided the basis for a rapid methodology to determine dissolved cellulose content. Development of rapid and facile screening techniques to determine the effectiveness of various ILs as solvents for cellulose or lignin will aid in the development of lignocellulosic based bioproducts. In this work, optical microscopy with and without the use of cross-polarized lenses, was used to monitor cellulose and lignin dissolution in two imidazolium-based and two phosphonium-based ILs as well as n,n-dimethylacetamide/lithium chloride (DMAc/LiCl), demonstrating that this technique could be applied more broadly than solely for ILs. The described optical microscopy methodology was more rapid and sensitive than more traditional techniques, such as visual inspection. The viscosity of [emim][OAc] (162 cP) is 100 times that of water at 20°C and could inhibit its use as a solvent for cellulose. There is a need for simple, low-cost and environmentally benign methods to reduce the viscosity of ILs to aid in cellulose dissolution. In this work, 4 wt% cellulose dissolved in [emim][OAc] was subjected to 50 psi CO2 and 20 psi N2, as a control environment, at both 50°C and 75°C. After 24 hours a nearly 2-fold increase in dissolved cellulose over the N2 control was demonstrated through the application of a 50 psi CO2 environment for cellulose dissolution in [emim][OAc] at 50°C. / Thesis (Master, Chemical Engineering) -- Queen's University, 2011-05-25 22:58:17.744

No description available.

A NMR study of the structure-dynamics relationships in heterogeneous materials is presented. In the first part, transport in soft-matter systems is studied using the pulsed field gradient NMR technique (PFG NMR). The molecular crowding effect in biological matter has been addressed using polymer solutions as model systems. By performing ensemble-based diffusion studies, the earlier obtained data on anomalous diffusion have been complemented. The transition to normal diffusion on a larger time scale has been shown. Taking advantages of the NMR approach, transport properties of microemulsions consisting of micellar colloids dissolved in liquid crystals have been investigated. The self-diffusivities measured under equilibrium conditions have shown weak correlations with microscopic ordering and macroscopic phase transitions occurring in the systems under study. The formation of micelles is shown to be decisive for macroscopic separation at the isotropic-nematic transition. The second part of the thesis covers heterogeneous effects in diffusion for fluids in porous solids, as probed using a combination of NMR diffusometry and structure characterization methods. Ionic liquids have been investigated, revealing a complex behavior under confinement. The attempts to correlate the observed characteristics of the ionic liquids with their internal chemical structure were undertaken. Finally, the series of nanoporous glasses with tunable pore structure characteristics were studied. Strong correlations between their structure and the preparation conditions as well as between the resulting transport properties have been shown.

Main group polycations and transition metal clusters had traditionally been synthesized via high-temperature routes by performing reactions in melts or by CTR, at room-temperature or lower temperature by using so-called superacid solvents, and at room-temperature in benzene–GaX3 media. Considering the major problems associated with higher temperature routes (e.g. long annealing time, risk of product decomposition, and low yield) and taking into account the toxicity of benzene and liquid SO2 in room-temperature or lower temperature synthesis, a soft and sustainable chemical approach has been developed, employing a Lewis-acidic IL [bmim]Cl/AlCl3. This new alternative reaction medium has proven to be an excellent solvent system for the single–step synthesis of main group polycations and transition metal clusters. X-ray diffraction and Raman spectroscopy have been used for the structural characterization of the isolated compounds. Physical properties and quantum chemical calculations of some of the compounds have also been carried out.

Líquidos iônicos imidazólios (LIIs) associados a ânions com caráter básico foram sintetizados, caracterizados e seu comportamento estudado em solução. Inicialmente a troca isotópica H/D preferencial no grupo C2-CH3 de sais de 1-nbutil-2,3-dimetilimidazólio (BMMI) foi avaliada. Ficou evidente que o contato entre os pares de íons e a atuação do ânion como uma base neutra influenciaram fortemente a deuteração. Após a análise dos resultados de RMN, cálculos de DFT (Teoria do Funcional de Densidade) e Difração de Raios X, um complexo entre uma molécula de água e alguns LI foi sugerido, modificando fortemente a estrutura organizacional e afetando também a troca isotópica nestes sais. Através do mecanismo reacional proposto, surgiu a possibilidade de deuteração de novos substratos contendo H ácidos, usando os LIIs como catalisadores. A reação de troca isotópica em alcinos e cetonas foi estudada e bons resultados foram obtidos. O efeito da variação de cátions e ânions na atividade catalítica foi analisado, assim como a variação dos substituintes dos substratos. Além disso, um estudo cinético foi realizado através de análises de RMN de 1H e o mecanismo reacional foi proposto. Por fim, a capacidade de formação de pares iônicos em soluções aquosas de LIIs foi avaliada na captura de CO2. Ótimos resultados foram obtidos e atribuídos à ocorrência de sorção física e química devido à ativação da água pelo LII. / Imidazolium based ionic liquids (ImIL) associated with basic anions were synthesized, characterized and studied. Initially the preferred H/D isotopic exchange to C2-CH3 group of 1-nbutyl-2,3-dimethylimidazolium salts (BMMI) was studied. In this context, it became evident that the ion-pairing formation and the anion action as a neutral base strongly influence the deuteration reaction. NMR analysis, theoretical calculation (Density Functional Theory) and X-ray Diffraction have been performed and a complex between a water molecule and the IL have been suggested, strongly modifying the IL structure and characteristics. The isotope exchange reaction in alkynes and ketones was studied using imidazolium based ionic liquids as catalysts and good results obtained. The effect of cation and anion variation on the catalyst activity were analyzed, also a variation of the substrate substituent’s. Also, a kinetic study was performed by 1H NMR analyzes and the reaction mechanism were proposed. Finally, the ability to form ion pair contact of ILs in aqueous solutions was evaluated for CO2 capture. Great results were obtained and this success can be attributed to the occurrence of physical and chemical sorption due to water activation by the IL.

Les membranes à base de liquides ioniques à conduction protonique (PCIL) sont très prometteuses comme électrolytes des piles à combustible haute température (HT- PEMFC) du fait de leur forte conductivité et stabilité à des températures supérieures à 100°C. L'objectif de cette thèse est de réaliser une étude approfondie sur l'évolution de la morphologie et des propriétés fonctionnelles, des membranes à base de liquides ioniques, avec i) la concentration en PCIL, ii) la méthode d’élaboration et iii) la structure chimique du PCIL. Afin de prouver la potentialité de ces membranes dans le HT-PEMFC, des tests préliminaires en pile sont réalisés et les phénomènes de dégradation des PCIL et des membranes en présence de peroxyde d'hydrogène sont étudiés. La première partie de ce travail est focalisée sur la caractérisation des membranes de Nafion® neutralisées avec le triéthylamine (Nafion-TEA) et gonflées avec triflate de triéthylammonium (TFTEA). Il a été montré que dans le Nafion-TEA sec, les cations présentent une organisation de type « string like » à l'interface hydrophobe-hydrophile. L’introduction du TFTEA dans la membrane Nafion-TEA ne détruit pas sa nano-structuration, mais augmente de manière significative la conductivité ionique du système. La deuxième partie de ce travail nous a permis d'établir que les membranes dopées élaborées par coulée-évaporation présentent une meilleure organisation et une meilleure tenue thermomécanique par rapport à celles obtenues par gonflement. La troisième partie de ce travail est focalisée sur l’étude de l'impact de la nature chimique du PCIL sur la morphologie et les propriétés fonctionnelles des membranes de Nafion-TEA. Il a été démontré que les PCILs avec longues chaînes perfluorées ne modifient pas la nano-structuration du Nafion-TEA. Ceci a un impact fort sur les propriétés de conductivité, de sorption d’eau et sur les propriétés thermomécaniques de la membrane. Dans la dernière partie, des Ionomères aromatiques ont été synthétisés afin de remplacer le Nafion-TEA. Malgré la structure similaire de la chaîne latérale des Ionomères aromatiques et du Nafion®, les membranes à base d’Ionomères aromatiques et TFTEA ne présentent aucune nano-structuration. De plus l’effet plastifiant du TFTEA est plus notable dans le cas des Ionomères aromatiques probablement du fait d’une distribution aléatoire des fonctions ioniques dans la membrane polymère. / The polymer electrolyte membranes based on Proton Conducting Ionic liquids (PCIL) are very promising systems for the high temperature-PEMFC technology owing to their good ionic conductivity and stability at temperatures above 100oC. The objective of this thesis work is to achieve a profound study on the evolution of morphology and consequent functional properties of the PCIL based polymer electrolyte membranes in function of: i). concentration of the PCIL, ii). the method of elaboration and iii). chemical structure of the PCIL. To demonstrate the potential of these membranes in HT-PEMFC, preliminary tests have been carried out in the fuel cell stack and degradation phenomena associated with PCILs and membranes in the presence of hydrogen peroxide have been studied. The first part of this work is focused on the characterization of Nafion® membranes neutralized with triethylamine (Nafion-TEA) and swollen with triethylammonium Triflate (TFTEA). It has been shown that Nafion-TEA exhibits a single layer string-like organization of inter-digited Triethylammonium cations at the hydrophobic-hydrophilic interface when in anhydrous state. The introduction of TFTEA into Nafion-TEA membrane does not destroy its nano-structuration but significantly boosts the anhydrous ionic conductivity and hydrophilicity of the system. The second part of this work has permitted us to establish the fact that doped membranes prepared by casting method have better organization and better thermo-mechanical properties compared to those obtained by swelling method. Third part of this work focuses on the impact of the chemical nature of the PCIL on the morphology and functional properties of Nafion-TEA membranes. It has been demonstrated that the PCILs with long perfluorinated chain length do not modify the nano-structuration of Nafion-TEA membranes at all. This has a strong impact on the ion-conducting, water-sorption and thermo-mechanical properties of the membrane. In the last part, aromatic ionomers were synthesized in order to replace Nafion-TEA in such PCIL based system. Despite the similar structure of the side chain of the synthesized aromatic ionomers and Nafion®, the membranes based on aromatic ionomers and TFTEA do not present any nano-structuration. Moreover, the plasticizing effect of TFTEA is more noticeable in the case of aromatic ionomers probably due to a random distribution functions in the ionic polymer membrane.