1000 resultados para Electrodic reactions


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A two-stage process in the formation of TiAl3 was found in the accumulative roll bonding (ARB) Ti/Al multilayers. The distribution of layer spacing did not become broad enough to lose the main features of the double exothermal behaviour. A modified model based on thin films was set up to describe the kinetic characteristics of the formation of TiAl3 in ARB samples.

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This thesis encompasses a series of investigations into the fundamental chemistry and spectroscopy of chemiluminescence (chemical reactions that produce light). This new knowledge enabled the development of innovative analytical methodologies for rapid chemical measurements in forensic science, industrial process monitoring and clinical diagnostics.

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This thesis was aimed at an increased awareness of the experiences of applicants for the ordained ministry in the Christian church. It also sought to identify important issues that need to be addressed by those responsible for the planning of selection processes.

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Describes the synthesis of thebaine and noroxymorphone - key intermediates in the synthesis of opiate drugs. The design and optimisation of these synthetic pathways were developed keeping in mind the concerns of industry.

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Chemical reactions between certain bis-cyclometalated iridium complexes, cerium(IV) and organic reducing agents in aqueous solution produce an emission of light which in some cases is more intense than that from analogous reactions with conventional ruthenium-based reagents, thus providing a new avenue for chemically-initiated luminescence detection.

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The reaction of acidic potassium permanganate with a wide range of compounds is known to produce a broad red emission, and there is strong evidence for an excited manganese(II) emitting species. Nevertheless, numerous researchers have proposed other emitters for reactions with acidic potassium permanganate, particularly for systems where fluorescent compounds were present, either as enhancers or reaction products. We have examined many reactions of this type and found that, in most cases, the same red emission was produced. There were, however, some exceptions, including the oxidation of dihydralazine, certain thiols and sulphite (each in the presence of an enhancer).

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A stable magnesium battery has been developed based on a magnesium anode, a poly(dioxyethane thiophene) (PEDOT) cathode and a near-saturated aqueous solution of LiCl, MgCl2, or mixture of these salts at pH of 11. This combination leads to a low water activity in the electrolyte, which thus suppresses the hydrogen evolution reaction on Mg, as well as producing a stable oxy-hydroxide film which protects the metal surface from freely corroding. The conducting polymer cathode is reduced somewhat during the discharge process, however, appears to be readily re-oxidised (as determined from the resistance) by the oxygen present in the cell. The cell is therefore primarily a Mg/O2 battery, however, the PEDOT appears to enhance the performance, in particular the discharge voltage.

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The reactivity and characterisation of solubilised manganese(IV) as a chemiluminescence reagent were systematically investigated. The analytical utility of this reagent was established for the determination of various alkaloids, pharmaceuticals and compounds of forensic interest. The methodology was then successfully applied to industrial process monitoring, clinical and illicit drug samples.

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Ionic liquids (ILs) represent a fascinating, and yet to be fully understood, medium for a variety of chemical, physical and biological processes. Electrochemical processes form an important subset of these that are particularly of interest, since ILs tend to be good electrochemical solvents and exhibit other properties which make them very useful as electrolytes in electrochemical devices. It is important therefore to understand the extent to which electrochemical reactions and processes behave in a relatively “normal”, for example aqueous solution, fashion as opposed to exhibiting phenomena more uniquely the product of their organic ionic nature. This perspective examines a range of electrochemical reactions in ionic liquids, in many cases in the context of real world applications, to highlight the phenomena as far as they are understood and where data gaps exist. The important areas of lithium and conducting polymer electrochemistry are discussed in detail.

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A simple and efficient palladium-catalyzed domino reaction for the synthesis of a series of C1-substituted tetrahydro-β-carbolines is described. This domino process involves a Heck reaction at the indole 2-position of a halogenated tryptamine precursor, followed by intramolecular aza-Michael addition.

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Palladium-catalyzed domino Heck–aza-Michael reactions for the synthesis of a series of C1-substituted tetrahydro-β-carbolines, tetrahydroisoquinolines and isoindolines are described. The domino process involves the initial intermolecular Heck reaction of an aryl bromide with an electron deficient alkene, followed by an intramolecular aza-Michael reaction to form the new N-heterocycle in high yield.

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A one-pot, three-component method incorporating a domino Heck–aza-Michael reaction has been developed for the rapid synthesis of functionalised tetrahydroisoquinolines. Following the in situ generation of an acrylamide, a domino process involving intermolecular Heck reaction and subsequent intramolecular aza-Michael addition affords tetrahydroisoquinolines bearing C1-acetamide functionality.

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An array of experimental and computational methods has been implement to elucidate the mechanisms of light producing chemical reactions that are important in nature and the laboratory.