Thesis (Ph. D.)--University of Wisconsin--Madison, 1948. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 100-102).

Potsdam, Universiẗat, Diss., 2002.

Biobased diamines are excellent precursors for the synthesis of non-isocyanate polyurethanes (NIPUs). We have prepared several biobased diamines using three different reactions for their synthesis. In the first method, we have carried out chain elongation of cellulose-derived 2,5-diformylfuran by the Henry reaction followed by reduction of the nitroalkene. Yields of the key step: Hantzsch Ester reduction, were 70-80%. Method two involves the Friedel-Crafts alkylation of furfurylamine with different ketones under acidic conditions. Yields of large-scale alkylation reaction were 60-77%. In method three, we combined the Henry reaction and Friedel-Crafts alkylation techniques to access diamines from hemicellulose-derived furfural. These diamines can be reacted with carbonates to access hydroxyalkylcarbamates in good yields, around 80%. We have also developed a novel method for accessing biscarbamates directly from dialdehydes in good yields, 70-94%. The hydroxyalkylcarbamates and biscarbamates are valuable precursors to obtain polyurethanes via the phosgene-free route.

No description available.

Ce travail de thèse présente une étude détaillée de la dissolution et de la fonctionnalisation de la cellulose dans les mélanges co-solvant/fluides sous et supercritiques. Plusieurs fluides ont été utilisés, notamment les mélanges supercritiques d’acétone/CO2 et d’éthanol/CO2, urée/CO2, l’eau sous critique, ainsi que les mélanges 1,8-Diazabicycloundec-7-ène(DBU)/CO2 et méthanol/DBU/CO2.La spectroscopie infrarouge a été utilisée pour étudier les interactions intermoléculaires dans les mélanges supercritiques d’acétone/CO2 et d’éthanol/CO2, à des différentes fractions molaires, dans un large domaine de température. Des calculs par dynamique moléculaires couplés à des mesures par spectroscopie infrarouge ont été réalisés pour comprendre les interactions liaisons hydrogènes dans l'eau sous et supercritique. Des suivis cinétiques in-situ par spectroscopie infrarouge pour optimiser la dissolution de la cellulose dans plusieurs solvants dans les conditions sous et supercritiques, ont été réalisés. Nous n’avons pas trouvé de signature spectrale de la dissolution de la cellulose dans les mélanges acétone/CO2 et éthanol/CO2. Par contre, la cellulose s'est transformée en cellulose carbamate dans le milieu urée/CO2 supercritique. Les photographies MEB de la cellulose traitée dans les liquides ioniques commutables, montrent une modification de la morphologie de la cellulose. Plusieurs techniques spectroscopiques ont été utilisées dans cette étude (FTIR en transmission ou en ATR, la CP/MAS RMN de solide, le MEB). Les calculs de chimie quantique nous ont permis de proposer un mécanisme réactionnel pour la réaction de la cellulose dans le mélange DBU/CO2. / This thesis presents a detailed study of the dissolution and the functionalization of cellulose in the co-solvent/sub and supercritical fluids. Many fluids have been used, including supercritical mixtures of acetone/CO2 and ethanol/CO2, urea/CO2 subcritical water, 1,8-Diazabicycloundec-7-ene (DBU)/CO2 mixture and methanol/DBU/CO2 mixture. Infrared spectroscopy was used to study the intermolecular interactions in the supercritical mixture of acetone/CO2 and ethanol/CO2, over a wide range of molar fractions and temperatures. Molecular dynamics simulations coupled with infrared spectroscopy measurements were performed to understand the hydrogen bonds interactions in sub and supercritical water, over a wide temperature range. In-situ kinetics studies using FT infrared spectroscopy, has been performed to optimize the dissolution of cellulose in various sub and supercritical solvents. We didn’t found any spectral signature of the dissolution of cellulose in the acetone/CO2 and the ethanol/CO2 mixtures. However, cellulose has been transformed to cellulose carbamate in the urea/supercritical CO2 mixture. The SEM photograph of cellulose treated in the switchable ionic liquids prepared from DBU/subcritical CO2 or DBU/methanol/subcritical CO2 showed a change in the cellulose morphology. Several spectroscopic techniques were used in this study (infrared transmission or ATR, CP / MAS solid NMR, SEM). The quantum calculations on models of configurations formed by CO2, DBU and cellobiose (to mimic the cellulose) were carried out and allowed us to propose a reaction mechanism for the reaction of the cellulose in the DBU/CO2 mixture.

Stuttgart, Univ., Diss., 2003.

Techn. Universiẗat, Diss., 2003--Berlin.

Malaria (vector: Anopheles gambiae) is a major infectious disease that kills about 1 million people each year. For the improvement of its treatment and vector control during the past decades, several issues such as high medicine cost, insecticide resistance, and lack of an effective vaccine have prevented adequate control of malaria. Additionally, the low selectivity of malaria vector insecticides also presents a public health problem. The purpose of developing novel carbamate insecticides in our laboratory is to offer effective and selective insecticide options to achieve the ultimate goal of malaria control. First, 50% inhibition concentration (IC50) data was collected from three mammalian AChEs with eight commercial carbamate insecticides by using the Ellman assay. The IC50 values varied from 57 nM to 7358 nM. The AChE sensitivity pattern and level were shown to be similar between the recombinant mouse and ICR male mouse brain cortex homogenate (slope = 0.99, R2 = 0.96). Then eight novel carbamate insecticides that are possible malaria vector control agents were selected for further neurotoxicity testing in non-target organisms. For commercial carbamate insecticides, the IC50 varied from 9.1 nM to 2,094 nM. For the novel carbamate insecticides, it varied from 58 nM to 388,800 nM. Based on IC50 data from previous work on A. gambiae, the selectivity index (IC50 of non-target species / IC50 A. gambiae) ranged from 0.17 to 5.64 and from 0.47 to 19,587 for commercial and novel carbamate insecticides, respectively. Subsequently, the AChE protein sequence alignment comparison and cladogram were used to compare the genetic and evolutionary relationship among five different organisms. The alignment score ranged from 88 for mouse vs. human to 54 for hen vs. T. californica. The evolutionary relationships among species was obtained from the cladogram. Recombinant mouse vs. recombinant human was shown to have the most similar inhibitor potency profiles (alignment score = 88, closest taxa position on cladogram, similar AChE sensitivity pattern [R2 = 0.81] and level [P > 0.05] to the novel carbamates). Neurotoxic esterase (NTE) assay showed that the novel carbamates did not significantly inhibit NTE, inhibition of which underlies a significant hazard for anticholinesterases, especially organophosphates, in several nontarget vertebrate organisms. The NTE activity in the presence of novel carbamate insecticides ranged from 93% to 116% of the control, while in the commercial group, bendiocarb significantly inhibited NTE, leaving only 76.5% of the initial reactivity at 1 mM inhibitor concentration. Further in vivo bioassay using Daphnia magna was conducted to compare the aquatic toxicity of commercial and novel carbamates. The data showed that except for PRC331 (3-tert-butylphenylmethylcarbamate), all novel carbamates were of similar potency as bendiocarb (LC50 = 611 nM) for aquatic toxicity, and their LC50 values ranged from 172 nM (PRC331) to 1109 nM. In conclusion, the novel carbamate insecticides would appear to be an improvement over commercial carbamate insecticides because of greater selectivity, negligible NTE inhibition capacity, but in some cases with potent in vivo toxicity to Daphnia magna. However, since the envisioned usage of these compounds is in bednets or as indoor residual sprays (IRS), any environmental exposures to nontarget aquatic organisms are expected to be minimal. / Master of Science

No description available.

A legislação brasileira estabelece o limite de 150 µg/L para os teores de carbamato de etila (CE ou uretana) em aguardentes. O presente trabalho indica que os teores de carbamato de etila em aguardentes podem ser reduzidos em até 92% do teor original após as aguardentes serem submetidas a uma nova destilação. Para amostras de aguardente recém destiladas (coletadas in loco) foi possível constatar que o CE também se forma após a destilação, e que a formação completa-se após 10 dias. A luz difusa não influenciou, quer na constante de velocidade quer na concentração de CE final. Esta, entretanto demonstrou-se dependente da temperatura. Observou-se que a reação ocorre com kobs de (6,4 ± 0,5) x 10-6 /s, a 25°C e pH 4,5, sendo este valor independente da origem da aguardente e da radiação luminosa. Os parâmetros de ativação para esta reação foram ΔH‡ 34 kcal/mol, ΔS‡ - 69 cal/K e ΔG‡ 54 kcal/mol. Foi possível estimar que o teor de uretana formado no interior do destilador foi inferior a 60% do CE total. Estudos com aguardente nas quais foi adicionado KOCN, indicaram que ocorre a formação de uretana com kobs (8,60 ± 0,4) x 10-5 /s, a 25°C, pH 4,5, com ΔH‡ 20,6 kcal/mol, ΔS‡ - 96,1 cal/K e ΔG‡ 48,7 kcal/mol. Esta reação não foi influenciada pela radiação luminosa (250 a 500 nm), bem como pelo teor alcoólico da aguardente (0,29 a 15,7 mol/L). O rendimento no teor de CE aumentou em função do teor alcoólico do meio, atingindo um valor máximo a 60% v/v. Cálculos quânticos sugeriram que o HNCO é a molécula reativa. Os resultados experimentais colhidos até o momento sugerem a existência de uma reação paralela consumindo parte do HNCO e, portanto limitando kobs e a relação [CE]teórico / [CE]experimental. A adição de NaCN à aguardente também conduz a formação de uretana, mas com constante de velocidade inferior a observada para o KOCN. / Brazilian law establishes the limit of 150 µg/L for ethyl carbamate (EC, urethane) contents in sugar cane spirits. The present work indicates that the levels of ethyl carbamate in spirits may be reduced up to 92% of the original content after undergoing a new distillation. It was observed that EC is also formed after distillation in recent distillated samples collected in loco and that the EC formation is completed after 10 days. The light did not influence either the rate constant or the final EC concentration. However, the rate constant proved to be temperature dependent. It was observed that the reaction occurs with kobs (6.4 ± 0.5) x 10-6 /s at 25°C and pH 4.5, which value is independent of the spirits origin and light radiation. The activation parameters for this reaction were ΔH‡ 34 kcal/mol, ΔS‡ - 69 cal/K and ΔG‡ 54 kcal/mol. It was estimated that the concentration of urethane formed inside the distiller was less than 60% of total EC. Studies adding KOCN in sugar cane spirits indicated that the formation of urethane occurs with kobs (8.60 ± 0.4) x 10-5 /s at 25°C, pH 4.5, with ΔH‡ 20.6 kcal/mol, ΔS‡ - 96.1 cal/K and ΔG‡ 48.7 kcal/mol. This reaction was not influenced by light radiation (250 to 500 nm), as well as the alcohol content of spirits (0.29 to 15.7 mol/L). The yield on EC content increased according to the alcohol content of the medium; reaching a maximum value of 60% v/v. Quantum calculations have suggested that HNCO is the reactive molecule. The experimental results collected so far suggest the existence of a parallel reaction which consumes part of HNCO and therefore limits kobs and the relationship [CE]theorical / [EC]experimental. The addition of NaCN to sugar cane spirits also leads to urethane formation, although with lower rate constant compared to the one observed for KOCN.