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1
Cader, Mohamed Shah Roshan. "The intercalation of bromine- and iodine fluorosulfate derivatives in solutions of fluorosulfuric acid." Thesis, University of British Columbia, 1986. http://hdl.handle.net/2429/25853.
Full textAbstract:
The oxidative intercalation of halogen fluorosulfate derivatives such as I(SO₃F) ₃, Br(SO₃F)₃, BrSO₃F, K[I(SO₃F)₄] and K[Br(SO₃F)₄] from solutions in fluorosulfuric acid into graphite (SP-1 and to a lesser extent HOPG) is studied. In addition, the intercalation of solvated cations of the type I₂₊ and NO⁺ is included in this research as well.
The results, supported by microanalysis, X-ray powder diffraction data, Raman frequency shifts, Solid state -¹⁹F-NMR spectroscopy and UV-visible optical spectra of the supernatant solutions support three different courses of the intercalation reactions:
a) At very high intercalant concentrations (about a five fold excess over the stoichiometrically required quantity) Hal (SO₃F)₃ and the anion [Hal(SO₃F)₄], with Hal - I or Br, intercalate without noticeable solvent cointercalation.
b) At intermediate concentrations, solvent intercalation is observed.
c) When low intercalant concentrations are used, the only intercalate is found to be the solvent HSO₃F.
In all the intercalation reactions except the NO⁺ (solv) promoted synthesis, first stage compounds are formed. These stage one GIC's with c-axis layer repeat distance I[sub c] - 8.0 A are found for the intercalants I₂₊(solv), I(SO₃F)₃, BrSO₃F and Br(SO₃F)₃ with compositions C₃₂SO₃F.₃HSO₃F.0-2I, C₂₂l(SO₃F)₃, C₁₁HSO₃F.0•5SO₃F.xBrSO₃F (x ≤ 0.025) and C[sub 26.8] Br.4SO₃F respectively. K[Hal(SO₃F)₄] (Hal - Br, I) in HSO₃F gave first stage products with formulae C₈₄Br.11•22SO₃F and C₈₆I.10-51SO₃F.
The NO⁺ (solv) induced reaction leads to a stage two compound with I[sub c] - 10.6 A, and a general composition of C[sub n] x SO₃F-yHSO₃F is proposed for the product which is compositionally inhomogeneous. In addition, the basal plane electrical conductivity enhancements are measured for the graphite-I₂₊(solv) and graphite-I(SO₃F)₃systems employing a contactless radio frequency induction method.Science, Faculty of
Chemistry, Department of
Graduate
2
Du, Toit Jacolene. "Effect of bromine and iodine in drinking water on the physiological parameters of broilers." Diss., University of Pretoria, 2010. http://hdl.handle.net/2263/27559.
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Assessment of a significant number of water samples across South Africa by Casey and Meyer over a number of years, revealed that high concentrations (30- 32 mg/L) of bromine (Br) occur naturally within groundwater in South Africa, hence a potentially hazardous chemical constituent (PHCC). Br, the only liquid non-metallic element, is ubiquitous and an abundant trace element, but it has not been conclusively shown to perform essential functions in plants, micro organisms or animals (NRC, 2005). The recommended limit (maximum limit for no risk) for Br in drinking water was set at 1 mg/L by Kempster et al. (1980); Casey and Meyer (2001) recommend the relevant safety guideline for Br to be 0.01 mg/L. The aim of this project was to establish the effect of Br and iodine (I) in drinking water on the physiological parameters of broilers. This will contribute to verifying and refining water quality guidelines. The effect of six treatments administered as sodium bromide (NaBr) and potassium iodide (KI): 0 mg Br/L and 0 mg I/L; 1 mg Br/L; 1mg Br/L and 0.7 mg I/L; 0.7 mg I/L; 3 mg Br/L; 3 mg Br/L and 0.7 mg I/L, in the drinking water of 540 mixed Ross broiler chickens was investigated. The trial ran over a 42-day growth period from Day 1 post-hatching where mortalities, water and feed intakes were recorded daily. Chickens were weighed weekly and slaughtered at 4 and 6 weeks of age. Blood samples were taken before slaughter and free T3 and T4 hormone levels were quantified. Thyroid gland, liver and kidney samples were analysed for Br and I quantity. The different treatments of Br, irrespective of I, significantly decreased water intake (P=0.0232) and feed intake (P=0.0035) over the 42 days. The overall interaction of Br and I had no significant effect on water (P=0.0928) and feed (P=0.9593) intakes thus I did have an effective ameliorating effect on Br. FCR, weight gain and mortalities were not significantly affected by Br intake. This was also found for free T3 and T4 hormone levels. Br had an overall effect on the thyroid gland (P=0.0457), liver (P=0.0025) and kidney (P=0.0032) with accumulation of the PHCC within these three organs. It was apparent that 1 and 3 mg Br/L water administered to broilers or ingestion rates of 1.59 and 4.44 mg Br/L per bird per day, over a production period of 42 days did affect the production parameters of the birds sub-clinically. Another derivation to refine the water quality guidelines was that the administration of 0.7 mg I/L water or ingestion rates of 1.1 mg I/L per bird per day did alleviate the severe detrimental effect of the high PHCC. The 3 mg Br/L guideline is thus not too restrictive. Further research exposing the animals for a longer time period (exceeding 42 days) and exposing mature animals (producing nutritional products for human consumption) to these treatments would assist in quantifying these results.Dissertation (MSc(Agric))--University of Pretoria, 2011.
Animal and Wildlife Sciences
unrestricted
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Rauhut, Christian Bernhard. "Preparation of Functionalized Organomagnesium Reagents by ortho-Magnesiation, Sulfoxide-, Iodine- and Bromine-Magnesium Exchange Reactions." Diss., lmu, 2008. http://nbn-resolving.de/urn:nbn:de:bvb:19-95656.
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García, de la Concepción María Belén. "Novel Halogen(I) Reagents in the C-sp3- and Csp3-Bond Functionalization." Doctoral thesis, Universitat Rovira i Virgili, 2018. http://hdl.handle.net/10803/663299.
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En el treball presentat en aquesta tesi es mostren els desenvolupaments importants realitzats sobre l’ús de reactius d'halogen(I), específicament en la funcionalització d’enllaços C(sp2)-H i C(sp3)-H mitjançant reactius de iode(I) i brom(I).
El present manuscrit està dividit en tres apartats principals:
1-Reactius de iode(I) per la difuncionalització d’alquens.
2- Aminació oxidativa d'enllaços C-(sp3)-H de tetrahidrocarbazoles.
3-Aplicació de reactius de iode(I) o catàlisi de brom en la síntesi formal de (±)-aspidospermidina.
En la primera secció sobre la difuncionalització d'alquens, hem presentat la síntesi general, aïllament i caracterització de nous reactius de iode(I) amb fórmula R4N[I(O2CAr)2]. Aquests compostos posseeixen alta estabilitat davant l’exposició a l'aire i la humitat. El nostre interès radica en l'exploració de reaccions promogudes per iode electrofílic cap a una iodooxigenació de derivats d’estirè.
En la segona secció, s'ha dut a terme una exploració sobre l'ús del reactiu de Varvoglis PhI(NPhth)2. Aquest es va utilitzar per a la síntesi de reactius de iode(I) i brom(I) amb lligands de ftalimida. Com l’aminació de tetrahidrocarbazoles en la posició 4 no s’ha explorat fins al moment, desenvolupem una metodologia innovadora per dur a terme l’aminación oxidativa en C(sp3)-H de derivats de tetrahidrocarbazol, utilitzant reactiu de iode(I) o catàlisi de brom.
Finalment, en el tercer capítol volíem demostrar la versatilitat i el rendiment dels reactius d'halògens descrits en el capítol anterior per a la síntesi de (±)-aspidospermidina.El trabajo presentado en esta tesis representa algunos desarrollos importantes en reactivos de halógeno(I), concretamente hacia la funcionalización de los enlaces C(sp2)-H y C(sp3)-H a través de reactivos de yodo(I) y bromo(I). El presente manuscrito está dividido en tres partes principales: 1- Reactivos de yodo(I) para la difuncionalización del alquenos. 2- Aminación oxidativa de enlaces C-(sp3)-H de tetrahidrocarbazoles 3- Aplicación de reactivos de yodo(I) o catálisis de bromo hacía la síntesis formal de (±)-aspidospermidina. En la primera sección sobre la difuncionalización de alquenos, hemos presentado una síntesis general, aislamiento y caracterización de varios reactivos de yodo(I) con la fórmula R4N[I(O2CAr)2]. Estos compuestos poseen alta estabilidad ante el aire y la humedad. Nuestro interés radica en la exploración de reacciones promovidas por yodo electrófilo hacia la yodooxigenación con derivados de estireno. En la segunda sección, se ha llevado a cabo una exploración del uso del reactivo de Varvoglis PhI(NPhth)2. Este reactivo se usó para la síntesis de reactivos de yodo(I) y bromo(I) con ligandos de ftalimida. Como la aminación de tetrahidrocarbazolas en la posición 4 no se ha sido explorada hasta el momento, se. llevó a cabo el desarrollo de una metodología innovadora para dar lugar a una aminación oxidativa en C(sp3) con derivados de tetrahidrocarbazol, usando reactivo de yodo(I) o catálisis de bromo. Finalmente, en el tercer capítulo queríamos demostrar la versatilidad y el rendimiento de los reactivos de halógenos descritos en el capítulo anterior para dar lugar a la síntesis de un compuesto natural, tal como (±)-aspidospermidina.
The work presented in this thesis represents some major developments in halogen(I) reagents, specifically towards the functionalization of C(sp2)-H and C(sp3)-H bonds through iodine(I)- and bromine(I)-reagents. The present manuscript is divided into three principal parts: 1- Iodine(I) reagents for vicinal alkene difunctionalization 2- Oxidative amination of C-(sp3)-H bonds of tetrahydrocarbazoles 3- Application of iodine(I) reagent or bromine catalysis to the formal synthesis of (±)-aspidospermidine. In the first section on alkene difunctionalization, we have presented a general synthesis, isolation and characterization of several novel iodine(I) reagents with the formula R4N[I(O2CAr)2]. These compounds exhibit high air and moisture stability. We were interested in the exploration of reactions promoted by electro-philic iodine towards a vicinal iodooxy-genation of styrene derivatives. In the second section an exploration of the use of Varvoglis reagent PhI(NPhth)2 has been carried out. This reagent was used to the synthesis of iodine(I) and bromine(I) reagents with phthalimide ligands to stabilize the electrophilic halogen center. As oxidative amination of tetrahydrocarbazoles in position 4 has not been explored so far, we developed an innovative methodology to carryout the C(sp3) oxidative amination of tetrahydrocarbazole derivatives using iodi-ne(I) reagent or bromine catalysis. Finally, in the third chapter we wanted to demonstrate the versatility and performance of halogen reagents described in the previous chapter, which were used in the synthesis of (±)-aspidospermidine.
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Hay, Timothy Deane. "MAX-DOAS measurements of bromine explosion events in McMurdo Sound, Antarctica." Thesis, University of Canterbury. Physics and Astronomy, 2010. http://hdl.handle.net/10092/5394.
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Reactive halogen species (RHS) are responsible for ozone depletion and oxidation of gaseous elemental mercury and dimethyl sulphide in the polar boundary layer, but the sources and mechanisms controlling their catalytic reaction cycles are still not completely understood. To further investigate these processes, ground– based Multi–Axis Differential Optical Absorption Spectroscopy (MAX-DOAS)
observations of boundary layer BrO and IO were made from a portable instrument platform in McMurdo Sound during the Antarctic spring of 2006 and 2007. Measurements of surface ozone, temperature, pressure, humidity, and wind speed and direction were also made, along with fourteen tethersonde soundings and the collection of snow samples for mercury analysis.
A spherical multiple scattering Monte Carlo radiative transfer model (RTM) was developed for the simulation of box-air-mass-factors (box-AMFs), which are used to determine the weighting functions and forward model differential slant column densities (DSCDs) required for optimal estimation. The RTM employed the backward adjoint simulation technique for the fast calculation of box-AMFs
for specific solar zenith angles (SZA) and MAX-DOAS measurement geometries. Rayleigh and Henyey-Greenstein scattering, ground topography and reflection, refraction, and molecular absorption by multiple species were included. Radiance and box-AMF simulations for MAX-DOAS measurements were compared with nine other RTMs and showed good agreement.
A maximum a posteriori (MAP) optimal estimation algorithm was developed to retrieve trace gas concentration profiles from the DSCDs derived from the DOAS analysis of the measured absorption spectra. The retrieval algorithm was validated by performing an inversion of artificial DSCDs, simulated from known NO2 profiles. Profiles with a maximum concentration near the ground were generally well reproduced, but the retrieval of elevated layers was less accurate. Retrieved partial vertical column densities (VCDs) were similar to the known values, and investigation of the averaging kernels indicated that these were the most reliable retrieval product. NO₂ profiles were also retrieved from measurements made at an NO₂ measurement and profiling intercomparison campaign in Cabauw, Netherlands in July 2009.
Boundary layer BrO was observed on several days throughout both measurement periods in McMurdo Sound, with a maximum retrieved surface mixing ratio of 14.4±0.3 ppt. The median partial VCDs up to 3km were 9.7±0.07 x 10¹² molec cm ⁻ in 2007, with a maximum of 2.3±0.07 x 10¹³ molec cm⁻², and 7.4±0.06 x 10¹² molec cm⁻² in 2006, with a maximum of 1.05 ± 0.07 x 1013 molec cm⁻². The median mixing ratio of 7.5±0.5 ppt for 2007 was significantly higher than
the median of 5.2±0.5 ppt observed in 2006, which may be related to the more extensive first year sea ice in 2007. These values are consistent with, though lower than estimated boundary layer BrO concentrations at other polar coastal sites. Four out of five observed partial ozone depletion events (ODEs) occurred during strong winds and blowing snow, while BrO was present in the boundary layer in
both stormy and calm conditions, consistent with the activation of RHS in these two weather extremes. Air mass back trajectories, modelled using the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model, indicated that the events were locally produced rather than transported from other sea ice zones. Boundary layer IO mixing ratios of 0.5–2.5±0.2 ppt were observed on several days. These values are low compared to measurements at Halley and Neumayer Stations, as well as mid-latitudes. Significantly higher total mercury concentrations observed in 2007 may be related to the higher boundary layer BrO
concentrations, but further measurements are required to verify this.
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Ishita, Keisuke. "Design, Synthesis and Evaluation of Carborane and Thiazole Derivatives." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1510937794366855.
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Zielcke, Johannes [Verfasser], and Ulrich [Akademischer Betreuer] Platt. "Observations of reactive bromine, iodine and chlorine species in the Arctic and Antarctic with Differential Optical Absorption Spectroscopy / Johannes Zielcke ; Betreuer: Ulrich Platt." Heidelberg : Universitätsbibliothek Heidelberg, 2015. http://d-nb.info/1180499611/34.
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Lövgren, Robin. "Four-component DFT calculations of phosphorescence parameters." Thesis, Linköping University, Computational Physics, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-19180.
Full textAbstract:
Oscillator strengths and transition energies are calculated for several mono-substitutes of benzene and naphthalene molecules. The substituents investigated are chlorine, bromine and iodine. Calculations for these molecules are presented, at the Hartree-Fock and DFT level of theory. The functional used in DFT is CAM-B3LYP.
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Cartwright, Julia Ann. "Noble gas components in Martian meteorites." Thesis, University of Manchester, 2010. https://www.research.manchester.ac.uk/portal/en/theses/noble-gas-components-in-martian-meteorites(4ed4e430-096d-43a8-964a-c367ab7b2f45).html.
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This thesis focuses on the analysis of heavy noble gases (argon, krypton and xenon) and halogens (chlorine, bromine and iodine) in Martian meteorites. In the absence of a sample-return mission, Martian meteorite analysis is essential for establishing evidence for an active fluid system, evaluating the potential for life and understanding the formation and evolution of Mars. Noble gas analysis has multiple applications for Martian meteorite study, as described in this thesis. The noble gas isotopic signatures of Earth’s atmosphere, Martian atmosphere and Martian interior are sufficiently different that they can be distinguished through noble gas analysis. Analysis of bulk and mineral separates of shergottites showed that Martian atmospheric Xe was distributed evenly amongst samples, whilst terrestrially weathered samples contained elevated concentrations of terrestrial atmospheric Xe. Both atmospheric components were introduced by weathering. Shock redistribution is responsible for the distribution of Martian atmosphere into more retentive sites. Crustal contamination may be responsible for the presence or absence of detectable 129Xe from the Martian atmosphere. Halogen abundances can be determined as an extension of the Ar-Ar dating technique. As the halogen system on Earth acts as a tracer for important fluid related processes, Martian halogen abundances in meteorites may provide a tracer for the Martian fluid system. Analysis of bulk and mineral separates of nakhlites showed that halogens are distributed amongst minor phases and clear variation of Br/Cl and I/Cl ratios was observed amongst samples. Elevated I concentrations in low temperature releases of finds NWA 998 and MIL 03346 are consistent with terrestrial contamination. Analysis of Nakhla, (a meteorite fall), showed a trend of elevated Br/Cl and I/Cl ratios in crush and low temperature releases, consistent with Br/Cl ratios observed in Martian rocks, soils and weathering products. In contrast, high temperature releases had lower I/Cl and Br/Cl ratios, which are broadly comparable to the terrestrial mantle. This trend may represent mixing of hydrothermal fluids (low Br/Cl and I/Cl) and surface brines (high Br/Cl and I/Cl). An impact-induced hydrothermal system may provide a mechanism for mixing of both fluid types. The crystallisation ages of nakhlite meteorites were determined using the Ar-Ar dating technique. The apparent ages measured were similar to previous Ar-Ar analysis, and older than reported for other chronometers. Previously unrecognised components were observed, including evidence for a trapped hydrous fluid. This Cl-rich component showed strong correlation with 40Ar and had 40Ar/36Ar and 40Ar/129XeXS ratios consistent with Martian atmosphere. As this component was released during crush and low temperature analysis, fluid inclusions formed by percolation of brines from the Martian surface are likely hosts. Both finds showed clear evidence of a trapped component with 40Ar/36Ar ratios similar to either terrestrial atmosphere or the Martian interior. A further component observed in olivine phases had low 40Ar/36Ar ratios, and likely formed by the release of 36Ar formed by cosmic-ray spallation reactions on iron.
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Widdifield, Cory. "Multinuclear Solid-State Magnetic Resonance Studies on ‘Exotic’ Quadrupolar Nuclei: Acquisition Methods, High-Order Effects, Quantum Chemical Computations, and NMR Crystallography." Thèse, Université d'Ottawa / University of Ottawa, 2012. http://hdl.handle.net/10393/20722.
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This dissertation attempts to extend the classes of halogen-containing systems which may be studied using solid-state nuclear magnetic resonance (SSNMR). As line shape broadening due to the quadrupolar interaction (QI) scales inversely with the applied field, high-field magnet technology is indispensable for this research. Combining advanced radiofrequency pulse sequences with high-field wideline data acquisition allowed for the collection of very broad SSNMR signals of all quadrupolar halogen nuclei (i.e., 35/37Cl, 79/81Br and 127I) within a reasonable amount of experimental time. The initial systems for study were of the MX2 variety (M = Mg, Ca, Sr, Ba; X = Cl, Br, I). In total, 9 anhydrous compounds were tested. The effects of hydrate formation were tested on 7 additional compounds. Systematic trends in the observed δiso values (and to a lesser extent, Ω and CQ) were found to be diagnostic of the extent of hydration in these materials. Resolving power was successfully tested using SrBr2, which possesses 4 magnetically unique sites. The composition of CaBr2•xH2O was convincingly determined using SSNMR data and the hydration trends noted above. The sensitivity of the QI to the local bonding environment (e.g., bond distance changes of less than 0.05 Å) was used to refine (when coupled with gauge-including projector augmented-wave density functional theory (GIPAW DFT) quantum chemical computations) the structure of MgBr2, and was used to correct prior NMR data for CaCl2 (earlier accounts had been performed upon a CaCl2 hydrate). During NMR data analysis of certain iodine-containing materials, it was found that standard fitting software (which uses perturbation theory) could not reproduce the observations. Proper analysis required the use of exact simulation software and allowed for the observation of high-order quadrupole-induced effects (HOQIE). This motivated further studies using rhenium-185/187 nuclei, where it was expected that HOQIE would be more dramatic. The observed rhenium SSNMR spectra possessed additional fine structure that had never been observed before experimentally, nor would be expected from currently-available perturbation theory analysis software. Lastly, preliminary results are shown where 127I SSNMR is used to study important supramolecular systems, and the composition of the popular synthetic reagent ‘GaI’ is elucidated.
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Faranda, Carmela Federica. "Behavior of halogens (Cl, Br, I) in alkali-rich felsic magmas at crustal depth : an experimental approach." Electronic Thesis or Diss., Orléans, 2023. http://www.theses.fr/2023ORLE1066.
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Le comportement des halogènes (F, Cl, Br et I) dans les systèmes magmatiques est loin d'être clairement compris. La communauté scientifique n'a qu'une connaissance fragmentaire des processus qui influencent le comportement de ces éléments pendant le stockage et l'ascension des magmas. Les études récentes du comportement des halogènes lourds comme le brome et l'iode se sont principalement concentrées sur les magmas liés à la subduction, dans le contexte du cycle géochimique des halogènes depuis la subduction jusqu'à l'atmosphère. Les études antérieures sur la solubilité des halogènes (à saturation en saumure) ont montré que les liquides calco-alcalins felsiques, fortement polymérisés, présentent une solubilité des halogènes (à l'exception du F) plus faible que les liquides felsiques riches en alcalins. En outre, les magmas riches en alcalins peuvent produire des éruptions de grand volume (par exemple, le système du rift est-africain), ce qui peut conduire à une émission massive d'halogènes dans l'atmosphère. Les émissions d'halogènes dans l'atmosphère sont donc potentiellement sous-estimées dans ces contextes, en raison d'un manque de compréhension détaillée du comportement des halogènes (et notamment du brome et de l'iode) pendant le dégazage magmatique. Dans ce contexte, l'objectif de cette thèse est de contraindre expérimentalement le partage des halogènes entre la phase fluide magmatique et le liquide silicaté dans les systèmes alcalins felsiques et de conduire une étude préliminaire de l'abondance des halogènes (notamment du brome et de l'iode) dans les verres alcalins naturels mafiques à felsiques provenant de différents contextes géodynamiques. Nous avons réalisé des expériences HP-HT (800 -1100 °C ; 10-200 MPa ; NNO-0.6 - NNO+3.4) en utilisant quatre compositions de liquide silicaté de teneur en SiO2 et de rapport molaire [(Na₂O+K₂O)/Al₂O₃] variables (phonolite, comendite, pantellerite et un analogue synthétique de la composition phonolitique). Nos résultats montrent que la composition du liquide a un impact important sur le partage des halogènes entre le fluide et le liquide silicaté. Le Dhalogens (avec Dhalogens = concentration de l'halogène dans la phase fluide/concentration de l'halogène dans le liquide silicaté) augmente avec la teneur en SiO₂ et diminue avec l'alcalinité des liquides, en accord avec les données de solubilité. Nous avons effectué une étude systématique de l'influence de la température et de la pression sur le partage des halogènes entre le fluide et le liquide silicaté et les résultats montrent que la température a un effet plus prononcé sur le partage que la pression. L'influence des conditions redox a également été étudiée et les résultats montrent que le D_I diminue avec la diminution de la fO2, tandis que DBr et le DCl montrent un effet inverse. Nous présentons la première détermination des abondances en halogènes lourds (Br et I) dans des verres felsiques riches en alcalins, avec des concentrations de l'ordre de ~10 ppm de Br et jusqu'à ~1 ppm de I dans les rhyolites riches en alcalins. Les concentrations en iode de ces verres sont au moins un ordre de grandeur plus élevées que les concentrations déterminées par l'analyse roche totale des produits volcaniques calco-alcalins publiées par ailleurs, mettant en exergue la nécessité de quantifier davantage les halogènes lourds dans les magmas afin de mieux évaluer les émissions atmosphériques d'halogènes et leur impact sur l'environnementThe behavior of halogens (F, Cl, Br and I) in magmatic systems is far from being clearly understood. The scientific community has only a fragmentary understanding of the processes that influence the behaviour of these elements during magma storage and ascent to the surface. Recent studies of heavy halogens (Br and I) behaviour have focused mainly on subduction-related magmas, in the context of the geochemical cycle of the halogens from subduction to the atmosphere. Previous studies of halogens solubility (at brine saturation) have shown that felsic, highly-polymerized calc-alkaline melts have lower halogens (except F) solubility than felsic alkali-rich melts. In addition, alkali-rich melts can produce large volume eruptions (e.g., East Africa Rift System), leading to potential massive release of halogens into the atmosphere. Emissions of halogens to the atmosphere are therefore likely to be underestimated, due to the lack of detailed understanding of the behavior of halogens (and in particular bromine and iodine) during magmatic degassing. In this work, we have addressed this gap by experimentally constraining fluid/melt halogen partitioning in felsic alkali-rich systems, with a focus on Br and I, and by a preliminary study of halogens abundances in natural mafic to felsic alkali-rich glasses from different geodynamic contexts. We performed HP-HT experiments (800°-1100 °C; 10 -200 MPa; NNO-0.6 -NNO+3.4) using four melt compositions, with variable SiO2 contents and [(Na₂O+K₂O)/Al₂O₃] molar ratios (natural phonolite, comendite and pantellerite and a synthetic analogue of phonolitic composition). Our results show that melt composition has a strong effect on the partitioning of halogens between fluid and melt. Dhalogens (with Dhalogens = halogen concentration in the fluid phase / halogen concentration in the silicate melt) increases with SiO₂ content and decreases with melt alkalinity, in agreement with the solubility data. We have carried out a systematic investigation of the influence of temperature and pressure on the fluid-melt partitioning of halogens and the results show that temperature has a more pronounced effect on partitioning than pressure. The effect of the redox conditions on halogens fluid/melt partitioning was also explored and the results indicate that DI decreases with decreasing fO₂, whereas DBr and DCl show the opposite effect. We present the first determination of heavy halogens (Br and I) abundances in felsic alkali-rich glasses, with concentrations in the order of ~10 ppm of Br and up to ~1 ppm of I in alkali-rich rhyolites. Iodine concentrations for these melts are at least an order of magnitude higher than concentrations determined by bulk rock analysis of calc-alkaline volcanic rocks in previous studies, highlighting the need for further quantification of heavy halogens in magmas to better assess their atmospheric emission and impact
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Thompson, Matthew Alan. "From femtoseconds to nanoseconds: Simulation of iodine bromide photodissociation dynamics in carbon dioxide clusters." 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:3256434.
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BOURGEOIS, CHARIGOT MARIE-THERESE. "Diffusion raman resonnante et structure des etats moleculaires excites." Reims, 1988. http://www.theses.fr/1988REIMS013.
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Des modeles d'etude sont proposes et appliques a differentes especes moleculaires. Les modeles suivants, de complexite croissante, sont presentes: approximation de reflexion, approximation harmonique, potentiels de morse, modele analytique tridimensionnel incluant l'effet duschinsky. Ce dernier modele est applique au cas de l'ozone et etendu ensuite aux molecules rendues non symetriques par une substitution isotopique
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Aranda, Alonso Clara. "Bulk and Interfacial Engineering to Enhance Photovoltaic Properties of Iodide and Bromide Perovskite Solar Cells." Doctoral thesis, Universitat Jaume I, 2019. http://hdl.handle.net/10803/668135.
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Perovskite solar cells (PSCs) have come to the forefront of photovoltaic technology due to their impressive power conversion efficiency (PCE) of up to 25%. This high efficiency comes together with great advances regarding large-scale deposition methods and a critical enhancement of device stabilities. However, important challenges remain in the shadows for commercialization of this technology.
his thesis addresses issues related with the stability under real operation condicions and those associated with the interfacial interactions. For both purposes, two main perovskite materials based in methylammonium lead halides (MAPbX3) were optimized: MAPbI3 and MAPbBr3. Coupled with a wide number of instrumentak techniques for bulk and interfacial characterization, a robust method to fabricate PSCs under moisture conditions was developed using iodide derivatives. On the other han, interfacial engineering with lithium additives in MAPbBr3 devices promoted a decrease in recombination mechanisms allowing to achieve a record open circuit poetential approaching 1.6 V.Las celdas solares de perovskita han alcanzado la primera línea de la tecnología fotovoltaica debido a las impresionantes eficiencias energéticas conseguidas, superando el 25% en la actualidad. Estos valores vienen acompañados de grandes avances como los métodos de depósito de los films a gran escala y a una mejora considerable en la estabilidad de estos dispositivos. Sin embargo, aún existen numerosas cuestiones que deben solucionarse para conseguir una comercialización real de esta tecnología. sta tesis doctoral aborda las cuestiones relacionadas precisamente con la estabilidad de los dispositivos bajo condiciones reales de operación, así como aquellas cuestiones relacionadas con las interacciones interfaciales. Para la consecución de ambos objetivos, dos formulaciones de perovskita han sido optimizadas con éxito: MAPbI3 y MAPbBr3. Junto con una amplia variedad de técnicas instrumentales de caracterización, tanto del bulk como de las regiones interfaciales, se ha desarrollado un método para la obtención de altas eficiencias bajo condiciones de humedad, así como la reducción de procesos de recombinación interfaciales que han permitido la obtención de valores récord de fotovoltage, alcanzanco los 1.6 V.
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Zaia, Dimas Augusto Morozin. "Determinação biamperométrica de íons iodato e iodeto em água do mar, iodato em sal de cozinha e íons bromato em farinha." Universidade de São Paulo, 1985. http://www.teses.usp.br/teses/disponiveis/46/46133/tde-27112014-104740/.
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Pelo uso da técnica biamperométrica modificada, pode-se determinar 35 ppb de íons iodato e 70 ppb de íons iodeto em água do mar; iodeto é determinado após sua oxidação a iodato com água de bromo no intervalo de pH entre 2,5 e 3,5 (o excesso de bromo é eliminado pelo aquecimento). Um estudo sistemático de pH foi efetuado para a elaboração do estudo de oxidação de íons iodeto a iodato com água de bromo, assim, como a oxidação de íons iodeto com água de bromo em várias temperaturas. Pode ser determinado 35 ppb de iodato em água do mar com %S de 3,9 e 70 ppb de íons iodeto em água do mar com %S de 5,8. O método proposto pode ser utililizado na determinação de íons iodato em sal de cozinha obtendo-se %S de 1,5. Por esta técnica também pode-se determinar íons bromato em farinha com melhores resultados em relação a volumetria. A análise de íons bromato, via biameprometria, pode ser efetuada por duas maneiras: diretamente na suspensão de farinha e por extração com Zn++/OH-, sendo que no primeiro caso pode-se determinar 15,2 ppm de íons bromato com %S de 7,00 e no segundo caso há necessidade de se utilizar um fator de correção, podendo-se chegar a concentrações de ppb.Using the modified biamperometria technique, one can determine 35 ppb IO3- and 70 ppb I- is determined after its oxidation to IO3- with bromine in a range of pH between 2,5 - 3,5 (the excess of bromine is eliminated at 50º C). A sistematic study of pH for the oxidation of I- to IO3- was done as well for the oxidation of I- with bromine in a range of temperature. 35 ppb IO3- in sea water can be determined with accuracy of 3,9%; 70 ppb I- in sea water can be determined with accuracy of 5,8%. This method can be used for the determination of IO3- in kitchen salt in with accuracy of 1,5%. BrO3- in flours can be determined by the some technique with better results in comparison with the volumetric classical methods. The analysis of BrO3- in flours by the modified biamperometry can be made through two ways: directly in the suspension of the flours in water and by extraction with Zn++/OH-. By the first one can determine 15,2 ppm BrO3- with 7,00% of accuracy; by the second way one need to use a factor for correction, for determination of ppb level.
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Groszko, Wayne. "An estimate of the global air-sea flux of methyl chloride, methyl bromide, and methyl iodide." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape9/PQDD_0016/NQ49265.pdf.
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LANTZ, DOMINIQUE. "Les halogenures : applications en chimie de synthese et dans la therapeutique." Strasbourg 1, 1989. http://www.theses.fr/1989STR15031.
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Lam, Son Ngoc. "Glycosylations via in situ formation of glycosyl iodides from glycosyl bromides." Thesis, The University of Arizona, 2001. http://hdl.handle.net/10150/278767.
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Glycosyl iodides have proven to be highly efficient and stereospecific glycosyl donors. Unfortunately with such high reactivity, they possess short shelf lives. Glycosyl bromides, on the other hand, are more robust than their iodo-counterparts. But, glycosylations using glycosyl bromides in the absence of Lewis acid catalysts are slow. Recently, we have demonstrated conditions augmenting glycosylations involving glycosyl bromides to levels matching the efficiency and stereospecificity of glycosyl iodides. Results of our studies will be discussed.
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Parisien, Mathieu. "Catalyst development for the direct arylation of aryl chlorides, bromides and iodides." Thesis, University of Ottawa (Canada), 2006. http://hdl.handle.net/10393/27163.
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Tricyclic biaryls were formed by a direct arylation reaction conducted in the presence of catalytic amounts of Pd(OAc)2 and tricyclohexylphosphine. Aryl chlorides, bromides and iodides could all be used and the methodology was applied to the synthesis of 6H-benzo[c]chomenes; 9, 10-dihydrophenanthenes; 5, 6-dihydrophenanthridines (if the nitrogen atom was protected) with yields ranging between 79% - >99%. Fluorene, dibenzofurans and carbazoles (unprotected NH) could also be formed in high yields (81%- 99%) using this technique.
It has been found that both electronic and steric factors influence the regioselectivity of the reaction. Furthermore, mechanistic investigations have been conducted to establish which one of four possible pathways is taking place. The results of these experiments point towards either a sigma-bond metathesis or an SE3 palladation.
The methodology described above was applied to the synthesis of natural products. (Abstract shortened by UMI.)
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McAvoy, Theodore Porter. "Managing Weeds and Soilborne Pests with Fumigant and Non-Fumigant Alternatives to Methyl Bromide." Diss., Virginia Tech, 2012. http://hdl.handle.net/10919/37813.
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Methyl bromide (MBr) was widely used as a soil fumigant to manage soilborne pests in plasticulture vegetable production; however, it has been banned by the United Nations Environment Programme. Alternatives to MBr must be implemented to sustain fresh market tomato productivity. Possible MBr alternatives include new fumigant compounds, improved plastic mulch, and grafting. Methyl iodide (MeI) and dimethyl disulfide (DMDS) were tested as fumigant alternatives to MBr for the control of yellow nutsedge and soilborne pathogens of tomato. Virtually impermeable film (VIF) and totally impermeable film (TIF) were tested for fumigant retention and yellow nutsedge control in tomato. Grafting onto resistant rootstocks was tested for bacterial wilt and nematode management in tomato. In the absence of a soil fumigant, TIF suppressed yellow nutsedge better than VIF. TIF increased fumigant retention compared to VIF at similar application rates. Reduced fumigant application rates could be used in combination with TIF while maintaining fumigant concentrations, weed control, and crop yields comparable to greater use rates with VIF. Shank applied DMDS rates could be lowered to 281 L/ha under TIF from 468 L/ha under VIF; shank applied MeI application rates could be reduced to 56 L/ha under TIF compared to 93 L/ha under VIF and drip applied DMDS could be reduced from 561 L/ha under VIF film to 374 L/ha under TIF. Grafting susceptible commercial tomato cultivars onto resistant tomato hybrid rootstocks increased yields and plant survival in bacterial wilt infested fields. â Cheong Gangâ , â BHN 998â , and â BHN 1054â were the best performing rootstocks for bacterial wilt resistance and tomato fruit yield in severely infested fields. Grafting increased tomato yield and decreased root galling from root-knot nematodes in an infested field. Hybrid rootstock â RST 106â resulted in the lowest root-knot nematode galling. In conclusion, TIF with reduced rates of DMDS or MeI is a viable MBr alternative for fresh market tomato production to retain effective doses of fumigant, manage yellow nutsedge and maintain yields. Grafting is an effective MBr alternative to manage bacterial wilt and root-knot nematode and maintain tomato yields.Ph. D.
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Grayfer, Tatyana. "Synthèse totale de la mallotojaponine C et bromofonctionnalisations de polyprénoïdes initiées par l'iode(III) hypervalent." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS349/document.
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Le paludisme est une maladie parasitaire qui présente une problématique de santé majeure, touchant actuellement plus de 200 millions de personnes dans le monde. Le développement de nouveaux médicaments est nécessaire pour succéder aux traitements existants qui perdent progressivement leur efficacité suite à l’émergence des résistances. Les produits naturels constituent une source d’inspiration inépuisable pour la recherche de nouveaux médicaments. Dans le cadre de cette thèse, nous nous sommes intéressés à deux familles de produits à propriétés antipaludiques : les mallotojaponines et les bromophycolides. Dans la première partie du projet, nous avons effectué la première synthèse totale de la mallotojaponine C. Nous avons également synthétisé une bibliothèque de ses analogues. Tous ces composés ont été testés contre Plasmodium falciparum responsable du paludisme et contre Trypanosoma brucei responsable de la maladie du sommeil. Nous avons confirmé l’activité antipaludique des mallotojaponines et découvert leur activité trypanocide. Dans la deuxième partie de ce projet, nous avons mis au point une méthode sélective et chimiodivergente de bromation des terpènes qui pourrait ensuite être appliquée à la synthèse des bromophycolides. En utilisant des réactifs d’iode(III) hypervalent pour générer des espèces bromonium électrophiles in situ à partir des bromures, nous avons réussi à mettre au point des conditions de bromocarbocyclisation, d’oxybromation et de dibromation des chaînes terpéniques. Dans tous les cas, les réactions sont rapides et faciles à mettre en œuvreMalaria is a parasitic disease affecting more than 200 million people in the world. The development of new antimalarial drugs is necessary in order to replace the existing treatments that are progressively becoming less efficient due to resistance phenomena. Natural products are an inexhaustible source of inspiration for the discovery of new drugs. In this project, we focused our attention on two natural products families exhibiting antimalarial properties: mallotojaponins and bromophycolides. In the first part of this project, we carried out the first total synthesis of mallotoajaponin C. We also synthesised a library of its analogues. All of these compounds were tested against Plasmodium falciparum responsible for malaria and against Trypanosoma brucei responsible for African sleeping sickness. We have confirmed the antimalarial activity of mallotojaponins and discovered their trypanocidal activity. In the second part of the project, we developed a chemodivergent and selective method of bromination of terpenes that could later be applied to the synthesis of bromophycolides. Using simple bromides and hypervalent iodine(III) reagents to generate electrophilic bromonium species in situ, we have shown that the reaction can be steered selectively towards the bromocarbocyclisation, the oxybromination or the dibromination of terpene chains. In all cases, the reactions are fast and easy to perform
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Steel, Colin James. "Automated radiosynthesis of 2-['1'1C]thymidine and ['1'1C]methyl halides for use in Positron Emission Tomography." Thesis, University of Hertfordshire, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.323444.
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Huang, Zishuai. "Studies Using Vibrational Sum Frequency Generation Spectroscopy:I. Salty Glycerol versus Salty Water Surface Organization: Bromide and Iodide Surface PropensitiesII. Influence of Salt Purity on Na+ and Palmitic Acid Interactions." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1373899240.
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Salama, Farid. "Etude de la photoexcitation dans l'ultra-violet lointain des halogènes piégés en matrice de gaz rare à basse température et étude de leur ionisation simple et double par impact protonique en phase gazeuse." Paris 6, 1986. http://www.theses.fr/1986PA066213.
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I. Etude des mécanismes de relaxation mis en jeu dans Cl2, Br2, I2 isolés en matrice, après excitation en UV proche ou lointain : émission structurée (transitions vibroniques) pour Cl2en UV proche et transitions électroniques avec interaction Rydberg-Valence en UV lointain; émission dans le visible pour Br2 et I2 quelle que soit l'énergie d'excitation; étude théorique des processus de relaxation. II. Observation d'ions moléculaires simplement ou doublement chargés, formés par échange de charge simple ou double étudié par spectrométrie de translation; analyse des règles de sélection : conservation du spin et observation des seuls états singlets pour Cl2, influence croissante du couplage spin-orbite lorsqu'on passe de Cl2, à Br2 puis I2.
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COSTA, FABIO E. da. "Desenvolvimento de sondas cirúrgicas radioguiadas com semicondutores de TlBr e com cristais cintiladores de CsI(Tl)." reponame:Repositório Institucional do IPEN, 2006. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11426.
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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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Черкашина, Наталья Олеговна, Наталія Олегівна Черкашина, Nataliia O. Cherkashyna, Лариса Александровна Ярышкина, Лариса Олександрівна Яришкіна, Larissa O. Yarishkіna, and Larisa A. Yaryshkіna. "Изучение возможности использования органических соединений галогенов в качестве ингибиторов коррозии в конструкциях оборотных систем предприятий коксохимической промышленности." Thesis, ФГБОУ ВО “Воронежский государственный технический университет”, Воронеж, 2015. http://eadnurt.diit.edu.ua/jspui/handle/123456789/8827.
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Черкашина, Н. О.
Изучение возможности использования органических соединений галогенов в качестве ингибиторов коррозии в конструкциях оборотных систем предприятий коксохимической промышленности / Н. О. Черкашина, Л. А. Ярышкина // Комплексные проблемы техносферной безопастности : материалы Междунар. науч.- практич. конф. (Воронеж, 12 ноября 2015 г.) / ФГБОУ ВО “Воронежский гос. тех. ун-т”. — Воронеж, 2015. — Ч. V. — С. 165—171.RU: В статье рассмотрены основные аспекты использования тетрапентиламмониййодида тетрапентиламмонийбромида в качестве ингибиторов коррозии в конструкциях оборотных циклов систем охлаждения предприятий коксохимической промышленности. Изучено влияние тетрапентиламмоний йодида и тетрапентиламмоний бромида на скорость коррозии материалов. Выявлено значительное снижение скорости коррозии материалов при глубоком обессоливании воды. Показано, что повышение температуры воды значительно влияет на скорость коррозии оборотных систем при её высокой минерализации и практически не сказывается в случае глубокого обессоливания воды.
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Mackeown, Henry. "Evaluation de la réduction du potentiel de formation des trihalométhanes et des acides haloacétiques par des procédés de traitement de l’eau potable : application sur des eaux impactées par les ions iodure et bromure." Thesis, Lille 1, 2019. http://www.theses.fr/2019LIL1R059.
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Les désinfectants utilisés dans la production d’eau potable réagissent avec la matière organique naturelle et produisent des sous-produits de désinfection. Les ressources en eaux potables dans les régions côtières sont susceptibles d’être impactées par des concentrations plus élevées en ions iodure entraînant la formation de sous-produits iodés, plus toxiques que leurs analogues bromés et chlorés. Deux méthodes analytiques par chromatographie gazeuse avec injection par headspace-trap ont été développées à l’Université de Lille : une méthode pour analyser les trihalométhanes – en particulier les espèces iodées (I-THMs) – et une méthode pour les acides haloacétiques (HAAs). Ces méthodes ont été utilisées pour une étude sur une usine de traitement de l’eau ainsi que pour l’évaluation de résines échangeuses d’ions, dans le cadre d’un ambitieux projet de modernisation de l’usine. En plus de tests de potentiels de formation, différents scénarios de concentrations croissantes en ions iodure et bromure ont été testés. Les résultats ont également été reliés à la caractérisation de la matière organique naturelle, avec l’abattement des substances humiques et des building blocks entraînant la plus grande réduction en potentiel de formation des THMs, durant la coagulation-décantation et lors du traitement par résines échangeuses d’ions. Les I-THMs et HAAs déjà formés furent significativement éliminés par les filtres à charbon actif sur l’usine de traitement, abaissant la cytotoxicité relative globale. La résine Amberlite IRA410 a eu la meilleure performance parmi les 4 résines testées sur l’abattement du carbone organique dissous et la réduction en potentiel de formation des sous-produits de désinfectionDisinfectants react with natural organic matter (NOM) to produce undesired disinfection by-products (DBPs). Drinking water resources in coastal areas can be impacted by higher concentrations of iodide leading to the formation of iodinated DBPs which are more toxic than their brominated and chlorinated analogues. Two analytical methods to analyse DBPs by headspace-trap gas chromatography were developed at Lille University: one for the trihalomethanes – with a focus on iodinated species (I-THMs) – and one for the haloacetic acids (HAAs). Those methods were implemented in a collaboration with De Watergroep to look at the removal of these DBP precursors in a full-scale drinking water treatment plant as well as in the assessment of ion exchange resins, as part of an ambitious project to modernize the plant. As well as formation potential tests on real waters, different scenarios of increasing iodide and bromide concentrations were tested. The results were also related to the characterization of the natural organic matter, with the removal of humic substances and building blocks leading to the greatest abatement of THM formation potential during coagulation-decantation and ion exchange treatment. Preformed I-THMs and HAAs were greatly removed by the granular activated carbon filters in the full scale plant, reducing the overall relative cytotoxicity. Amberlite IRA410 had the best performance amongst 4 resins on NOM removal and DBP formation potential reduction
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Gauduchon, Emmanuelle. "Fonctionnalisation régiosélective en position 4 ou 5 ducycle 1,2,3-thiadiazole et applications." Poitiers, 1998. http://www.theses.fr/1998POIT2333.
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Dans la premiere partie de ce travail, nous avons rationalise la preparation de matieres premieres 1,2,3-thiadiazoliques monofonctionnalisees en position 4 ou 5. Nous avons ainsi obtenu des esters, acides, derives d'acide et amines qui nous ont permis de realiser la synthese deux series d'amides n-substitues (n-arylthiadiazolylcarboxamides et n-thiadiazolylbenzamides) et une serie d'aldimines conjuguees (n-thiadiazolylbenzaldimines). Dans la seconde partie, nous avons prepare trois carbures 1,2,3-thiadiazoliques et transforme les amines primaires 1,2,3-thiadiazoliques en derives halogenes. Nous avons ensuite mis au point la preparation des 5-magnesio-1,2,3-thiadiazoles et des 4-magnesio-1,2,3-thiadiazoles ; grace a l'action de ces reactifs sur les derives carbonyles, nous avons pu introduire selectivement sur la structure une fonction alcool secondaire (huit exemples) ou une fonction alcool tertiaire (quatre exemples), soit en position 5, soit en position 4. Enfin, les tests biologiques standard effectues par les services agrochimiques de novartis sur trente-cinq de nos produits ont permis de constater que plusieurs d'entre eux montrent une activite fongicide et/ou herbicide notable, suffisamment prononcee pour justifier des developpements ulterieurs.
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PEREIRA, MARIA da C. C. "Desenvolvimento de cristais baseados em iodeto de césio para aplicação como detectores de radiação." reponame:Repositório Institucional do IPEN, 2006. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11434.
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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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Pereira, Maria da Conceição Costa. "Desenvolvimento de cristais baseados em iodeto de Césio para aplicação como detectores de radiação." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/85/85131/tde-16052012-084114/.
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Cintiladores inorgânicos com tempo de decaimento de luminescência rápido, densidade alta e boa produção de luz têm sido objeto de estudos para aplicações em física nuclear, física de energias altas, tomografia nuclear e outros campos da ciência e da engenharia. Cristais de cintilação baseados em iodeto de césio (Csl) são materiais que apresentam higroscopia relativamente baixa, número atômico alto, fácil manuseio e custo baixo, características que favorecem o seu uso como detectores de radiação. Neste trabalho descreve-se a obtenção de cristais Csl puro, Csl:Br e Csl:Pb, utilizando-se a técnica de Bridgman. A concentração do elemento dopante bromo (Br) foi estudada no intervalo de 1,5x10-1 M a 10-2 M e o elemento chumbo (Pb) no intervalo de 10-2 M a 5x10-4 M. Para avaliar os cintiladores desenvolvidos foram efetuadas medidas sistemáticas de emissão de luminescência e tempo de decaimento de luminescência para a radiação gama, ensaios de transmitância óptica, ensaios de microdureza Vickers, determinações da distribuição dos dopantes ao longo dos cristais crescidos e análise da resposta dos cristais à radiação gama no intervalo de energia de 350 keV a 1330 keV e partículas alfa provenientes de fonte de 241Am com energia de 5,54 MeV. Os resultados obtidos de tempo de decaimento de luminescência para os cristais CsI:Br e CsI:Pb, no intervalo de 13 ns a 19 ns, mostraram-se promissores para medidas de alta energia. O estudo de microdureza mostrou um aumento significativo em função da concentração dos elementos dopantes, quando comparado ao cristal Csl puro, melhorando desta forma a resistência mecânica dos cristais crescidos. A validade de utilização desses cristais como sensores de radiação para medidas de radiação gama e partículas alfa, pode ser demonstrada pelos resultados da resposta à radiação.Inorganic scintillators with fast luminescence decay time, high density and high light output have been the object of studies for application in nuclear physics, high energy physics, nuclear tomography and other fields of science and engineering. Scintillation crystals based on cesium iodide (CsI) are matters with relatively low higroscopy, high atomic number, easy handling and low cost, characteristics that favor their use as radiation detectors. In this work, the growth of pure CsI crystals, CsI:Br and CsI:Pb, using the Bridgman technique, is described. The concentration of the bromine doping element (Br) was studied in the range of 1,5x10-1 M to 10-2 M and the lead (Pb) in the range of 10-2 M to 5x10-4 M. To evaluate the scintillators developed, systematic measurements were carried out for luminescence emission and luminescence decay time for gamma radiation, optical transmittance assays, Vickers micro-hardness assays, determination of the doping elements distribution along the grown crystals and analysis of crystals response to the gamma radiation in the energy range of 350 keV to 1330 keV and alpha particles from a 241Am source, with energy of 5.54 MeV. It was obtained 13 ns to 19 ns for luminescence decay time for CsI:Br and CsI:Pb crystals. These results were very promising. The results obtained for micro-hardness showed a significant increase in function of the doping elements concentration, when compared to the pure CsI crystal, increasing consequently the mechanical resistance of the grown crystals. The validity of using these crystals as radiation sensors may be seen from the results of their response to gamma radiation and alpha particles.
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Wu, Dan. "Synergie d'effets stériques, électroniques et bifonctionnels pour la conception de catalyseurs métalliques hautement sélectifs promus par des éléments non métalliques." Thesis, Lille, 2020. http://www.theses.fr/2020LILUR056.
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L'épuisement des ressources fossiles et les préoccupations environnementales croissantes encouragent la production de produits chimiques et de combustibles durables à partir des ressources de la biomasse. La sélectivité est le paramètre principal pour les processus catalytiques hétérogènes, en particulier pour la conversion catalytique de molécules à base de biomasse, qui sont enrichies en groupes fonctionnels et aboutissent à divers produits. Outre les propriétés intrinsèques telles que la phase active, la taille des particules, la morphologie et les interactions métal-support, récemment, une modification rationnelle vers la chimie de surface des catalyseurs métalliques a attiré une attention intensive pour les processus catalytiques sélectifs. Dans cette thèse, la modification de catalyseurs métalliques (Pd, Ru) avec divers promoteurs non métalliques (iode, brome et amines) et diverses stratégies (génération d'acidité in-situ, désactivation sélective, effet électronique et empreinte moléculaire) a été développée. Des réactions industrielles importantes telles que l'éthérification réductrice, l'hydrodésoxygénation, le clivage des composés modèles de la lignine et l'hydrogénation des aromatiques ont été étudiées.La modification du catalyseur Pd avec de l'iode et du brome a été étudiée dans le chapitre 3 ~ 4. Les relations structure-performance ont été étudiées par des réactions catalytiques et diverses caractérisations in-situ et ex-situ. Nous avons constaté que l'iode et le brome retirent des électrons du Pd, conduisant à des atomes d'iode et de brome chargés négativement sur la surface du Pd. La dissociation hétérolytique de l'hydrogène sur les sites Pd-I et Pd-Br conduit à la génération in-situ d'acidité de Brönsted. Les catalyseurs bifonctionnels acide-métal Pd-I et Pd-Br ont présenté une efficacité élevée pour l'éthérification réductrice d'aldéhydes avec de l'alcool et l'hydrodésoxygénation du 5-hydroxyméthylfurfural en diméthylfurane, respectivement.Au chapitre 5, la modification des catalyseurs métalliques avec des halogènes a été étendue au catalyseur Ru. Le catalyseur Ru-Br a démontré une sélectivité élevée pour le clivage du composé modèle de lignine diphényléther en mono-aromatiques. Des recherches plus poussées indiquent que les sites de terrasse sur les nanoparticules de Ru, qui sont responsables de l'hydrogénation des cycles aromatiques, sont sélectivement désactivés par les atomes de Br. De plus, les atomes de Br retirent des électrons de Ru, conduisant à des nanoparticules de Ru chargées positives. Les nanoparticules de Ru déficientes en électrons ont présenté une activité améliorée pour l'hydrogénolyse des liaisons C-O riches en électrons. La synergie de la désactivation sélective et de l'effet électronique a permis au catalyseur Ru-Br une efficacité élevée pour la production de phénol et de benzène à partir d'éther diphénylique avec une sélectivité élevée.Sur la base de la compréhension approfondie des effets multifonctionnels des modificateurs non métalliques sur les catalyseurs métalliques, une stratégie d'impression moléculaire a été proposée au chapitre 6. L'empreinte moléculaire pour la préparation d'un catalyseur hétérogène imprimé implique l'adsorption d'une molécule modèle, la désactivation avec des empoisonneurs avec réserve de îlots actifs non empoisonnés de forme et de taille prédéterminées pour la transformation sélective des molécules correspondant aux modèles. Nous démontrons cette stratégie d'hydrogénation sélective de molécules aromatiques avec différents radicaux alkyles par dépôt préliminaire de ces molécules comme matrice sur catalyseur Pd et désactivation à l'aide de diméthylaminopropylamine (DMAPA). La stratégie élaborée permet une application pratique pertinente à l'hydrogénation sélective et à l'élimination du benzène cancérigène du mélange d'aromatiques et peut être étendue pour l'amélioration de la sélectivité de nombreuses réactions catalytiquesThe depletion of fossil resources and increasing environmental concerns encourage the production of sustainable chemicals and fuels from biomass resources. Selectivity is the primary parameter for heterogeneous catalytic processes, especially for the catalytic conversion of biomass-based molecules, containing a lot of functional groups with generation of various products. Recently, rational modification towards surface chemistry of metal catalysts has attracted intensive attention to tune the activity and selectivity. In this thesis, the modification of noble metal catalysts such as Pd and Ru with various non-metallic promoters such as iodine, bromine, and amines has been developed. These modifications lead to various effects like in-situ acidity generation, selective deactivation, electronic effect, and molecular imprinting. Important industrial reactions such as reductive etherification, hydrodeoxygenation, cleavage of lignin model compounds, and aromatics hydrogenation were investigated. The thesis consists of 7 chapters and 219 pages.In Chapter 1, a literature review of the recent progress in tuning catalytic properties of metal catalysts with non-metallic modifiers will be introduced. Different modification strategies will be clarified. And a general analysis will be proposed about the effects imposed by non-metallic modifiers of metal catalysts. Various industrial important reactions with the selectivity problems are discussed to elucidate the promotion effects of the non-metallic modifiers in catalysis.Chapter 2 introduces the experimental details about the preparation, characterization, and catalytic evaluation of the catalysts. Modification of Pd catalyst with iodine and bromine was investigated in Chapter 3 ~ 4. The structure-performance relationships were studied by catalytic reactions and various in-situ and ex-situ characterizations. We found that iodine and bromine withdraw electrons from Pd, leading to negative charged iodine and bromine atoms on Pd surface. Heterolytic dissociation of hydrogen on the Pd-I and Pd-Br sites leads to the in-situ generation of Brönsted acidity. The acid-metal bifunctional Pd-I and Pd-Br catalysts exhibited high efficiency for the reductive etherification of aldehydes with alcohol and the hydrodeoxygenation of 5-hydroxymethylfurfural to dimethylfuran, respectively.In Chapter 5, the modification of metal catalysts with halogens was extended to Ru catalyst. Ru-Br catalyst has been developed and demonstrated high selectivity for the cleavage of lignin model compound diphenyl ether to mono aromatics. Further investigations indicate that the terrace sites on Ru nanoparticles, which are responsible for aromatic-rings hydrogenation, selectively deactivated by Br atoms. Moreover, Br as a strongly electronegative element withdraws electrons from Ru, leading to positively charged Ru nanoparticles. The electron-deficient Ru nanoparticles exhibited enhanced activity for hydrogenolysis of electron-rich C-O bonds. The synergy of selective deactivation and electronic effect enabled Ru-Br catalyst high efficiency for the production of phenol and benzene from diphenyl ether with high selectivity.Based on the deep understanding of the multifunctional effects of non-metallic modifiers of metal catalysts, a molecularly imprinting strategy has been proposed in Chapter 6. Molecular imprinting for the preparation of imprinted heterogeneous catalyst involves adsorption of a template molecule, deactivation with poisoners with reservation of non-poisoned active islands with pre-determined shape and size for selective transformation of the molecules corresponding to templates. We demonstrate this strategy for selective hydrogenation of aromatic molecules with different alkyl radicals by preliminary deposition of these molecules as template over Pd catalyst and deactivation using dimethylaminopropylamine (DMAPA)
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Harfmann, Eric. "Verres thiohalogenes de mercure et de plomb transparents dans l' IR. Synthèse, nouvelles compositions, structure." Phd thesis, Université Sciences et Technologies - Bordeaux I, 1995. http://tel.archives-ouvertes.fr/tel-00143241.
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Les verres thiohalogènes de mercure et de plomb présentent un excellent domaine de transparence s'étendant de 0.6 micronmètre dans l'infrarouge. L'étude comparative avec des matériaux existants montre l'interet de ces verres en tant que transmetteurs IR. L'etude a porte sur la synthèse, la caractérisation physico-chimique et structurale de verres issus de système de base sulfure de mercure, bromure de plomb et iodure de plomb. Les contraintes spécifiques liées au développement de ces matériaux sont discutées. L'influence des conditions d'élaboration et de la composition sur les propriétés des verres obtenus a été étudiée et de nouvelles compositions vitreuses aux performances accrues ont été découvertes. L'étude structurale par spectroscopie de vibration IR, RMN, absorption et diffusion X confirme l'originalité de ces verres qui ne contiennent aucun formateur classique. Une tentative de modélisation par Reverse Monte Carlo conclue ce travail.
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(5930183), Angela R. Raso. "Iodine, Bromine, and Chlorine – Emission Rates and Sources." Thesis, 2018.
Find full textAbstract:
Halogen chemistry in the Arctic boundary layer catalytically destroys O3 and impacts the chemical lifetimes of hydrocarbons, the HOx-NOx cycle, and atmospheric mercury. While many advances have been made in the last several decades in understanding the sources, sinks, and recycling pathways of halogens in the Arctic there are still many unknowns. Previous studies have shown that Br2, BrCl and Cl2 are produced photochemically in the Arctic tundra snowpack, but the magnitude of this production is still poorly understood. Additionally, while there have been suggestions that the tundra snowpack should also produce I2, there have been no previous measurements of I2 in the Arctic. The lack of measurements of the halogen production capacity of Arctic snowpacks has left the community to rely on one-dimensional modeling to estimate the impact of snowpack-derived halogen chemistry on the Arctic atmosphere. Because modeling is inherently dependent on understanding recycling mechanisms, mixing processes, and sinks this leaves the effect of halogens on atmospheric chemistry in the Arctic highly uncertain.
This work describes efforts to address these uncertainties through measurements made during two field campaigns in Utqiaġvik (formerly Barrow), Alaska in January – February 2014, and February – May 2016. The first measurements of I2 in the Arctic, both in the snowpack interstitial air, and in the air above the snowpack demonstrate that iodine chemistry is active in the Arctic atmosphere, and that I2 is produced photochemically in the tundra snowpack. The effects of active iodine chemistry on both O3 and bromine chemistry is examined through zero- and one dimensional modeling. The first speciated measurements of snowpack phase iodine reveal that much like previous reports of iodine enriched aerosols, the Arctic snowpack is highly enriched in iodine. Vertical profiles of I- in the snowpack suggest that there is a consistent, non-radiation dependent source of iodine to the Arctic environment. It seems likely that this source is transport of iodine-enriched aerosols from the mid-latitudes. However, unlike the Antarctic, and previous
observations in the mid-latitudes, most Arctic snowpack phase iodine is inorganic, which may contradict transport from the mid-latitudes as a source. One-dimensional modeling was also utilized, in conjunction with the first vertical profile measurements of Br2 and Cl2 between 1 and
7 m above the snowpack surface to examine the community’s understanding of recycling mechanisms, mixing, sources, and sinks of halogens in the Arctic Atmosphere.
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Wishkerman, Asher [Verfasser]. "Bromine and iodine in plant-soil systems / Asher Wishkerman." 2006. http://d-nb.info/980347416/34.
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Chen, Yen-Ru, and 陳嬿如. "Determination of arsenic, iodine and bromine compounds in foods using HPLC-ICP-MS." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/4qf2su.
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Wroblewski, Witold. "Computational Investigations of Bromine and Iodine Halogen Bonded Complexes and The Proline Catalyzed Direct Aldol Reaction." Thesis, 2012. http://hdl.handle.net/10214/3938.
Full textAbstract:
Halogen bonding is a non-covalent interaction that has significant impact in different sub-disciplines of chemistry. Until recently it has been largely ignored due to the greater prevalence of hydrogen bonding. Non-bonding interactions have long been a problem for density functional theory due to the theory’s local nature. This has lead to the creation of new functionals such as the M06 and M06-2X methods or the addition of an empirical correction to existing methods to accurately describe medium distance interactions. Examination of halogen bonds requires the use of a basis set that is optimized for all halogens such as def2-TZVP, which uses effective-core potentials for iodine for efficiency and is close enough to the basis set limit to ignore BSSE. These new methods and basis sets are judged against the CT7/04 database to determine their accuracy and efficiency. The M06-2X and ωB97XD exchange correlation functionals coupled with the def2-TZVP basis set produce the most accurate method/basis set combinations which are used to benchmark these methods and basis sets against the Hal77/12 database proposed in this work. Geometries of the Hal77/12 database are optimized using M06-2X/def2-TZVP, M06-2X/def2-QZVP, ωB97XD/def2-TZVP, ωB97XD/def2-TZVP, MP2/def2-TZVP, and CCSD(T)/def2-TZVP. The geometries optimized at the CCSD(T)/def2-TZVP level and their respective single point energies are used as the reference values for benchmarking. The best method/basis set combination was ωB97XD/def2-TZVP with a deviation 2.78 kJ/mol from the reference values. The proline catalyzed direct aldol reaction is an important example of a organocatalyst with the ability to form carbon carbon bonds. The computational assessment of the mechanisms energetics has long been difficult due to the size of the system. A new approach using parameterized coupled cluster theory, LPNO-CCSD and LPNO-pCCSD/IIa, is used to evaluate the energetics of the mechanism. The single point energies of the coupled cluster approach are compared to density functional theory results. The mechanism is evaluated in the gas phase, in water, and in DMSO to assess the utility of these newer approaches in solvents. The mechanism for the reaction is different in the gas phase than in water and DMSO. The single point energies evaluated in water and DMSO are nearly identical and suggest that the two solvents could be used interchangeably in a laboratory setting.
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Barnes, Michael Dean. "The photoexcitation spectra of transition region species in reactions of potassium + sodium halides (X = chlorine, bromine, iodine)." Thesis, 1991. http://hdl.handle.net/1911/16417.
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The photoexcitation spectra of transition region species formed in bimolecular reactions of K + NaX (X = Cl, Br, I) have been observed by measuring the intensity of sodium D line emission at 589.0 nm as a function of excitation wavelengths between 595 and 640 nm. The portion of the spectrum measured for the K + NaCl system is qualitatively similar to that previously observed by Magurie, et al (MAG86). The spectra obtained for the K + NaBr and NaI systems are significantly different than that of the K + NaCl system, and show a distinct feature centered at approximately 610 nm, and indicate that the reaction dynamics are quite different for the heavier sodium halide systems. The results of classical trajectory calculations performed using K + NaCl potential energy surfaces suggest that the structure in the K + NaBr and K + NaI spectra is not due to a mass effect; but rather from unique features of the potential energy surfaces for these reactions which are, as yet, unknown. Because of insufficient theoretical and experimental information, interpretation of these results in terms of the dynamical processes in these reactions is not yet possible. However, several different possible mechanisms of this structure are discussed which can be experimentally tested. Results of proposed future experiments should be able to provide the necessary information to understand the nature of these spectra.
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Rauhut, Christian Bernhard [Verfasser]. "Preparation of functionalized organomagnesium Reagents by ortho-magnesiation, sulfoxide-, iodine- and bromine-magnesium exchange reactions / Christian Bernhard Rauhut." 2008. http://d-nb.info/99267414X/34.
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Huang, Shin-yi, and 黃馨儀. "Determination of Trace Multi-element and The Specitaiton Analysis of Iodine and Bromine in infant food Using ICP-MS." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/6xch64.
Full textAbstract:
碩士國立中山大學
化學系研究所
104
First parts presents a method based on DRC-ICP-MS for simultaneous determination of Cr, As, Sn, Cd, I, Hg, Pb in infant food. For detection of Cr, As and Cd, an ICP-MS equipped with a dynamic reaction cell (DRC) was used. The interfering 40Ar12C+, 35Cl16OH+, 40Ar12CH+, 40Ar35Cl+, 95Mo16O+ ions at masses 52, 53, 75 and 111 were reduced by using O2 as reaction cell gas. The limit of detection for multi-element were in the range of 0.0009–0.008 ng mL-1. All analytical procedures are subject to the standard quality control procedures. The accuracy of the method was validated using three kinds of reference materials NIST SRM 8435, NRCC DOLT-3 and NIST SRM 1568a. Methodology developed here was applied to investigate multi-element in infant food and brown rice. Second parts presents a method based on HPLC-DRC-ICP-MS for the simultaneous determination of Iodine and Bromine in infant food. The separation was performed on an anion exchange column PRP-X100 using a gradient elution program between 20 mM NH4NO3 at pH 10.2 as first mobile phase and 120 mM NH4NO3 at pH 10.2 as the second one. Separation of the Iodine and Bromine species was carried out in less than 6 min. The detection limit for Bromate, Bromide, Iodate and Iodide were 0.070 ng mL-1, 0.067 ng mL-1, 0.006 ng mL-1 and 0.008 ng mL-1, respectively. Reproducibility was 4.8% for 5 replicate injections. Iodine and Bromine species were extracted from infant food using 5 mL 10% TMAH and microwave assisted extraction procedure. The extraction efficiency of Iodine and Bromine were about 91% and 93% for 5 minutes at 90oC. The accuracy of the method was validated using reference materials NIST SRM 8435. Methodology developed here was applied to investigate Iodine and Bromine speciation in bottled water, seaweed and infant food.
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Wu, Yu-Jui, and 吳毓瑞. "Thermal Chemistry of 2-Propynyl Bromide and 1-Propynyl Iodide on the Ag(111) Surface." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/77323690037892680355.
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ZHUANG, HE-MU, and 莊賀木. "The study of bromide and iodide effect on the synthesis of benzyl esters with tertiary amine as catalyst." Thesis, 1987. http://ndltd.ncl.edu.tw/handle/29170130475205910213.
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Shie, Ming-Shiou, and 謝明修. "Kinetics of Electron Transfer and Dye Regeneration of Ruthenium-based TiO2 Solar Cells in Iodide and Bromide Electrolyte." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/91795685761401668902.
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碩士國立交通大學
應用化學系碩博士班
102
Photo-induced Absorption (PIA), Transient Absorption decay measurements (TAD), Charge Extraction (CE) and transient Photovoltage decay measurement (TVD) were carried out to investigate the electron transfer kinetics and the photovoltaic performance of the four Ru-based dye-sensitized solar cell (DSSC) in iodide-based electrolyte or bromide-based electrolytes. With CE measurement, we observed a specific down shift of the conduction band edge of titanium dioxide sensitiged with the ruthenium complex containing the electron-withdrawing group on the bipyridine ligand. Is result indicated that the direction of dipole moment of the Ru complexes modified with electron-withdrawing group favors better interaction with the conduction band electrons than the others. The regeneration rate of dye cations obtained by the TAD measurement using were much slower with Br3- than with I3-, consistent with the trend of photocurrents of the devices. We found that the regeneration rate constant of the Ru-3 device was located on the Marcus normal-region, but the others were on the Marcus inverted-region. The DSSC using Ru-1 as a sensitizer and 3Br-/Br3- as electrolyte exhibited the best performance with overall power conversion efficiency 5.09 % with a short-circuit current density (JSC) 6.307 mAcm-2, an open-circuit voltage (VOC) 1.02 V, and a fill factor of 0.79. The VOC value of 3Br-/Br3- (1.02 V)was significantly greater than that of 3I-/I3- (0.655 V) due to the more positive Fermi level of 3Br-/Br3- Than that of 3I-/I3-.
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ZHAO, CHENG-LONG, and 趙澄龍. "The study of iodide and bromide effect on the synthesis of benzyl ethers with tertiary amine as catalyst." Thesis, 1989. http://ndltd.ncl.edu.tw/handle/70812034395120293749.
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Kuperstock, Jacob Edwin. "Synthesis and luminescent behavior of piperazinium chlorocuprates(I) and copper(I) iodide and bromide complexes of aliphatic diamine ligands /." 2009. http://hdl.handle.net/10288/1197.
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Lin, Ming-Han, and 林明翰. "Fabrication and Characterization of Solar Cells and Ammonia Sensors with Lead Halide Iodide and Lead Halide Bromide Perovskite Materials." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/b9k9ez.
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Chen, Chia-Wei, and 陳家偉. "1.Iodine-Promoted Generation of ortho-Quinone Methide Intermediate and its Application for C－S Bond Cross－Coupling Reaction2.CuI/Oxalic Diamide-Catalyzed Cross－Coupling of Thiols with Aryl Bromides." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/55653412691026136869.
Full textAbstract:
碩士國立中興大學
化學系所
105
In the first part of this thesis, a new and efficient method has been described for generation of o-quinone methides via iodine-induced dehydroxylation of 2-(hydroxymethyl)phenols. The formed reactive o-quinone methide intermediates were trapped by thiols providing stable 2-[(alkyl or arylthio)methyl]phenols under mild conditions. The second part of this thesis, we report a general copper-catalyzed cross-coupling of thiols with aryl bromides by using N-aryl-N''-alkyl oxalic diamide (L3) or N,N''-dialkyl oxalic diamide (L5) as the ligands. Both aryl- and alkyl thiols can be coupled with unactivated aryl bromides to give the desired products in good yields for the first time. Furthermore, this system features broad substrate scope and good tolerance of functional groups. Importantly, the oxalic diamides are stable and can be prepared easily from commercially available cheap starting materials.