The synthesis of complexes [M(OCHMeCH2NMeCH2)2] (5, M = Mg; 7, M = Zn) is described. Treatment of MeHNCH2CH2NMeH (1) with 2-methyloxirane (2) gave diol (HOCHMeCH2NMeCH2)2 (3), which upon reaction with equimolar amounts of MR2 (4, M = Mg, R = Bu; 6, M = Zn, R = Et) gave 5 and 7. The thermal behavior and vapor pressure of 5 and 7 were investigated to show whether they are suited as CVD (= chemical vapor deposition) and/or spin-coating precursors for MgO or ZnO layer formation. Thermogravimetric (TG) studies revealed that 5 and 7 decompose between 80–530 °C forming MgO and ZnO as evidenced by PXRD studies. In addition, TG-MS-coupled experiments were carried out with 7 proving that decomposition occurs by M–O, C–O, C–N and C–C bond cleavages, as evidenced from the detection of fragments such as CH4N+, C2H4N+, C2H5N+, CH2O+, C2H2O+ and C2H3O+. The vapor pressure of 7 was measured at 10.4 mbar at 160 °C, while 5 is non-volatile. The layers obtained by CVD are dense and conformal with a somewhat granulated surface morphology as evidenced by SEM studies. In addition, spin–coating experiments using 5 and 7 as precursors were applied. The corresponding MO layer thicknesses are between 7–140 nm (CVD) or 80 nm and 65 nm (5, 7; spin-coating). EDX and XPS measurements confirm the formation of MgO and ZnO films, however, containing 12–24 mol% (CVD) or 5–9 mol% (spin-coating) carbon. GIXRD studies verify the crystalline character of the deposited layers obtained by CVD and the spin-coating processes.

The decrease in thermal decomposition temperature led to the amorphization of RuO2, and nano RuO2 particles were uniformly dispersed in amorphous Ta2O5 matrix. Such nano particles induced the increase in effective surface area for oxygen evolution and change in rate determining step, resulting in a significant decrease in oxygen overpotential. This excellent achievement induced a significant decrease in cell voltage of 0.7 V compared to lead alloy anodes and a voltage reduction of 37 % was achieved for copper electrowinning. Another distinct feature of the amorphous anodes is that nano RuO2 particles increase the overpotential of the unwanted side reaction on the anode, so that the anodic deposition of PbO2 can be completely inhibited. Therefore, the amorphous RuO2-Ta2O5/Ti anodes developed in this thesis have a high possibility to improve the purity of electrowon metal, reduce the maintenance of electrolysis process, prolong the lifetime of the anode, and make a low impact to environment. / 博士(工学) / Doctor of Philosophy in Engineering / 同志社大学 / Doshisha University

[pt] Os ciclos termoquímicos de decomposição de água relacionados ao enxofre são uma importante classe de processos químicos considerados para a produção de hidrogênio. Recentemente, a decomposição térmica do sulfato de magnésio e sulfato de amônio tem sido relatada como uma potencial operação unitária em um desses ciclos. Portanto, algum interesse tem sido observado no uso de catalisadores para diminuir a energia de ativação de sulfatos que se decompõem em altas temperaturas, como o magnésio e a adição de um agente modificador para facilitar a separação dos produtos no caso de sulfatos que se decompõem em baixas temperaturas como amônio. Neste contexto, a presente tese relata os resultados da modelagem termodinâmica e cinética associada a este sistema de reação na presença de Pd suportado sobre gama-Al(2)O(3). Para o sistema Mg a presença de tais espécies é responsável por deslocar a temperatura de decomposição para valores mais baixos em pelo menos 100 graus C. Observou-se que o teor de magnésio ainda está orientado para a formação de MgO. Os resultados obtidos indicam que o catalisador Pd/Al(2)O(3) pode ser uma boa alternativa na redução da temperatura de decomposição térmica, pois sua presença foi responsável por diminuir a energia de ativação do processo de 368,2 para 258,8 kJ.mol(-1). Para o sistema NH4 pode-se observar que ocorre em quatro etapas e a formação de sulfato de alumínio, sendo a última espécie portadora de sulfato, proporciona a separação do óxido de enxofre liberando-o em uma etapa diferente dos demais produtos gasosos. A presença de paládio pode atuar como redutor da energia de ativação desta etapa, deslocando a temperatura de decomposição para valores inferiores em pelo menos 90 graus C e a reduzindo os valores de energia de ativação entre 12 – 30 por cento abaixo do encontrado na literatura oriundos de modelos gráficos. / [en] The sulfur related thermochemical water-splitting cycles are an important class of chemical processes considered for hydrogen production. Recently, the magnesium and the ammonium sulfate thermal decomposition have been reported as a potential unit operation in one of these cycles. Therefore, some interest has been observed in the use of catalysts to lower the activation energy for sulfates that decompose in high temperatures, as such magnesium and the addition of a modifying agent to facilitate separation of the products in the case of sulfates that decompose into low temperatures as ammonium. In this context, the present thesis reports the thermodynamics and kinetics modeling results associated with this reactions systems in the presence of a Pd supported over gamma-Al(2)O(3). For Mg system the presence of such species is responsible for shifting the decomposition temperature to lower values in at least 100 degrees C. It was observed that the magnesium content is still oriented towards MgO formation. The obtained results indicate that the Pd/Al(2)O(3) catalyst could be a good alternative in reducing the thermal decomposition temperature as its presence was responsible for diminishing the process activation energy from 368.2 to 258.8 kJ.mol(-1). For NH(4) system it can be observed four steps for reactions and formation of aluminum sulfate, as the last sulfate bearing species, provided the separation of the sulfur oxide releasing it in a different step from the other gaseous products. The presence of palladium can act as an activation energy reducer, shifting the decomposition temperature to lower values in at least 90 degrees C and decreasing the activation energy by 12 – 30 percent than that found in the literature.

Cette étude vise à mieux comprendre les réactions impliquées dans le craquage thermique des huiles en basins sédimentaires. Des pyrolyses d'octane, de toluène et de mélanges octane/toluène ont été effectuées entre 330°C et 450°C et des pressions allant de 1 bar à 700 bar. Le mécanisme radicalaire développé permet de rendre compte de l’influence de la température et de la pression sur la distribution des produits ainsi que sur la conversion jusqu'aux conditions de gisement (200°C, 150-1000 bar). Les pyrolyses du toluène pur et du mélange octane/toluène ont permis de modéliser le rôle inhibiteur des alkylaromatiques sur le craquage des hydrocarbures. Cette étude démontre l'importance des co réactions et donc de la composition des huiles sur la stabilité thermique des pétroles en gisements / This study aims at a better understanding of the reactions involved in the thermal cracking of oil within sedimentary basins. Pyrolysis of octane, toluene and mixtures of octane / toluene were performed between 330°C and 450°C and at pressures going from 1 bar to 700 bar. The constructed radical mechanism allows to report the influence of temperature and pressure on the distribution of products as well as the conversion from laboratory to reservoir conditions (200°C, 150-1000 bar). The pyrolysis of pure toluene and the octane / toluene mixture allowed to model the inhibition effect of alkylaromatics on the cracking of hydrocarbons. This study demonstrates the importance of co reactions and thus the composition of oil on the thermal stability of petroleums in reservoirs

Marine aerosols have attracted increasing attention over the past 15 years because of their potential significance for global climate modelling. The size distribution of these aerosols extends from super-micrometer sea salt mode particles down through 150 nm accumulation mode particles, 40 nm Aitken mode particles and nucleation mode particles which extend from 25 nm right down to clusters of a few molecules. The process by which the submicrometer modes form and grow and their composition have remained topics of debate throughout this time in large part because of the difficulties associated with determining their composition and relating it to proposed models of the formation process. The work compared the modality of marine aerosol influencing the South-east-Queensland region with that of other environmental aerosols in the region. The aerosol was found to be consistent with marine aerosols observed elsewhere with concentrations below 1000 cm-3 and frequently exhibiting the distinct bimodal structure associated with cloud processing, consisting of an Aitken mode at approximately 40 nm, an accumulation mode in the range 100-200 nm and a coarse mode attributed to sea salt between 600 and 1200 nm. This work included the development of two new techniques for aerosol research. The first technique measures aerosol density using a combination of aerosol size distribution and gravimetric mass concentration measurements. This technique was used to measure the density of a number of submicrometer aerosols including laboratory generated NaCl aerosol and ambient aerosol. The densities for the laboratory generated aerosols were found to be similar to those for the bulk materials used to produce them. The technique, extended to super-micrometer particle size range may find application in ambient aerosol research where it could be used to discriminate between periods when the aerosol is dominated by NaCl and periods when the density is more representative of crustal material or sulfates. The technique may also prove useful in laboratory or industrial settings for investigating particle density or in case where the composition is known, morphology and porosity. The second technique developed, integrates the existing physicochemical techniques of volatilisation and hygroscopic growth analysis to investigate particle composition in terms of both the volatilisation temperatures of the chemical constituents and their contribution to particle hygroscopic behaviour. The resulting volatilisation and humidification tandem differential mobility analyser or VH-TDMA, has proven to be a valuable research tool which is being used in ongoing research. Findings of investigations relating the composition of the submicrometer marine aerosol modes to candidate models for their formation are presented. Sea salt was not found in the numerically dominant particle type in coastal nucleation mode or marine Aitken and accumulation modes examined on the Southeast Queensland coast during periods where back trajectories indicated marine origin. The work suggests that all three submicrometer modes contain the same four volatile chemical species and an insoluble non-volatile residue. The volatility and hygroscopic behaviours of the particles are consistent with a composition consisting of a core composed of sulfuric acid, ammonium sulfate and an iodine oxide coated with a volatile organic compound. The volume fraction of the sulfuric acid like species in the particles shows a strong dependence on particle size.

This thesis focuses on the synthesis and characterisation of organoclays. X-ray diffraction has been used to study the changes in the basal spacings of montmorillonite clay and surfactant-intercalated organoclays. Variation in the d-spacing was found to be a step function of the surfactant concentration. Three different molecular environments for surfactant octadecyltrimethylammonium bromide (ODTMA) within the surface-modified montmorillonite are proposed upon the basis of their different decomposition temperatures. High-resolution thermogravimetric analysis (HRTG) shows that the thermal decomposition of montmorillonite modified with ODTMA takes place in four steps attributing to dehydration of adsorbed water, dehydration of water hydrating metal cations, loss of surfactant and the loss of OH units respectively. In addition, it has shown that the decomposition procedure of DODMA and TOMA modified clays are very different from that of ODTMA modified ones. The surfactant decomposition takes place in several steps in the DODMA and TOMA modified clays while for ODTMA modified clays, it shows only one step for the decomposition of surfactant. Also TG was proved to be a useful tool to estimate the amount of surfactant within the organoclays. A model is proposed in which, up to 0.4 CEC, a surfactant monolayer is formed between the montmorillonite clay layers; up to 0.8 CEC, a lateral-bilayer arrangement is formed; and above 1.5 CEC, a pseudotrimolecular layer is formed, with excess surfactant adsorbed on the clay surface. While for dimethyldioctadecylammonium bromide (DODMA) and trioctadecylmethylammonium bromide (TOMA) modified clays, since the larger sizes of the surfactants, some layers of montmorillonite are kept unaltered because of steric effects. The configurations of surfactant within these organoclays usually take paraffin type layers. Thermal analysis also provides an indication of the thermal stability of the organoclay as shown by different starting decomposition temperatures. FTIR was used as a guide to determine the phase state of the organoclay interlayers as determined from the CH asymmetric stretching vibration of the surfactants to provide more information on surfactant configurations. It was used to study the changes in the spectra of the surfactant ODTMA upon intercalation into a sodium montmorillonite. Surfaces of montmorillonites were modified using ultrasonic and hydrothermal methods through the intercalation and adsorption of the cationic surfactant ODTMA. Changes in the surfaces and structure were characterized using electron microscopy. The ultrasonic preparation method results in a higher surfactant concentration within the montmorillonite interlayer when compared with that from the hydrothermal method. Both XRD patterns and TEM images demonstrate that SWy-2-Namontmorillonite contains superlayers. TEM images of organoclays prepared at high surfactant concentrations show alternate basal spacings between neighboring layers. SEM images show that modification with surfactant will reduce the clay particle aggregation. Organoclays prepared at low surfactant concentration display curved flakes, whereas they become flat with increasing intercalated surfactant. Fundamentally this thesis has increased the knowledge base of the structural and morphological properties of organo-montmorillonite clays. The configurations of surfactant in the organoclays have been further investigated and three different molecular environments for surfactant ODTMA within the surface-modified montmorillonite are proposed upon the basis of their different decomposition temperatures. Changes in the spectra of the surfactant upon intercalation into clay have been investigated in details. Novel surfactant-modified montmorillonite results in the formation of new nanophases with the potential for the removal of organic contaminants from aqueous media and for the removal of hydrocarbon spills on roads.