Carbohydrate research remains one of the most exciting endeavors in the field of organic chemistry. The importance of carbohydrates needs little elaboration. Quite literally, without glucose, cellulose, and starch, the necessities of life such as food, clothing, and shelter would be missing. In our laboratory, we have for some time been interested in one particular class of carbohydrate derivatives - the aldohexopyranosyl cyanides.

Please read the abstract in the section 00front of this document / Dissertation (MSc)--University of Pretoria, 2010. / Chemistry / unrestricted

Orientador: Carlos Frederico de Oliveira Graeff / Banca: Claudio José Magon / Banca: Augusto Batagin Neto / Banca: Luis Vicente de Andrade Scalvi / Banca: José Humberto Dias da Silva / O Programa de Pós Graduação em Ciência e Tecnologia de Materiais, PosMat, tem caráter institucional e integra as atividade de pesquisa em materiais de diversos campi / Resumo: Materiais e dispositivos baseados em compostos orgânicos desempenham um importante papel em diversas áreas da aplicação tecnológica devido às suas interessantes propriedades eletro-magneto-ópticas, adicionadas às suas características mecânicas únicas, facilidade de processamento, versatilidade de síntese e baixo custo relativo. Apesar do proeminente campo de aplicação destes materiais, muitos aspectos associados às sua ciência básica são ainda pouco compreendidos. Nesse cenário destaca-se o fenômeno de Magnetoresistência Orgânica (OMAR, da sigla em inglês). Tal fenômeno encontra-se associado a variações significativas da condutividade elétrica de dispositivos orgânicos induzidas por pequenos campos magnéticos externos em temperatura ambiente e tem sido observado em diversificados materiais poliméricos e moleculares. No presente trabalho avaliou-se o fenômeno de OMAR apresentando por um Diodo Emissor de Luz baseado na molécula de Alq3-. Medidas de Espectroscopia de Impedância Elétrica na presença de um Campo Magnético estático externo (EIE-CM) foram realizadas sobre o referido dispositivo para diferentes temperaturas. Métodos diferenciados de aquisição e manipulação de dados foram empregados a fim de remover a dependência temporal dos sinais tipicamente observados. Os seguintes Efeitos do Campo Magnético (MFE, da sigla em inglês) foram observados sobre a resposta elétrica do dispositivo: (i) redução de cerca de 1% na resistência, efeito praticamente constante para todo o espectro de frequência e; (ii) variações significativas na capacitância, com intensificação do efeito de Capacitância Negativa em baixas frequências. Como suporte para a interpretação dos resultados experimentais foram realizadas simulações empregando-se duas abordagens: Circuitos Equivalentes e Análise de perturbações de pequenos sinais (em inglês, Small Signal Analisys) via soluções numéricas das equações... / Abstract: Materials and devices based on organic compounds play and important role in various technological applications, mainly due to their interesting electrical-magneto-optical properties combined with their unique mechanical properties, easy processing, versatility of synthesis and relatively low cost. Despite the prominent application field of these materials many aspects associated with their basic science are still not well understood. in this context the Organic Magnetorresstance phenomenon (OMAR) deserves to be highlighted. This phenomenon is associated with significant changes in the electrical conductivity of organic devices induced by the presence of small external magnetic fields at room temperature, being observed in various polymeric and molecular materials. In this study we have investigated the OMAR phenomenon in Alq3-based OLEDs. Electrical impedance spectroscopy tehcnique in the presence of an external static magnetic field (EIS-MF) was employed in the experiments; distinct tempertures were considered. Differentiated methods of acquisition and data manipulation were employed to remove te typically observed signal time dependence. The following magnetic field effects (MFE) were observed on the electrical response of the device: (i) a constant reduction of around 1% in the resistance over the entire frequency spectrum and; (ii) significant changes in the capacitance followed by an intensification of the negative capacitance effect at low frequencies. Simulations employing two different approaches were carried out for the interpretation of the experimental results: (i) Equivalent Circuits and (ii) Small Signal Analysis via numerical solutions of the Boltzmann transport equations by Drift-Diffusion approach. The results suggest that the observed MFE can be associated with an increase in the effective mobility of the charge carriers and a reduction in the biomolecular rate in the device. The results were interpreted in terms of... / Doutor

Orientador: Rosane Aparecida Gomes Battistelle / Co-orientadora: Ilza Machado Kaiser / Banca: Aloisio Costa Sampaio / Banca: Ivaldo de Domenico Valarelli / Resumo: Cada vez mais a busca de soluções ambientalmente corretas para a destinação dos resíduos sólidos tem se tornado urgente, impulsionada pelo rápido crescimento populacional e pelo desenvolvimento econômico. A compostagem é uma ferramenta tradicional e sustentável de grande importância para o tratamento da parte orgânica dos resíduos sólidos, realizando o processamento dos resíduos orgânicos originados da agroindústria, da agricultura, do comércio e dos domicílios, como os restos de alimentos. Este trabalho aborda o tratamento de resíduos de alimentos provenientes de restaurantes, por meio de uma pesquisa aplicada experimental com três modelos de processamento (dois industriais e um doméstico). Um processo de co-compostagem, com adição de outros resíduos estruturantes, foi desenvolvido e comparado com os principais modelos de compostagem. Este estudo objetiva avaliar as técnicas para otimizar os processos de compostagem, por meio da avaliação de parâmetros de degradação biológica dos resíduos sólidos (pH, umidade, temperatura, teor de oxigênio, relação carbono/nitrogênio e qualidade do composto produzido), contribuindo para a escolha do melhor método para a destinação adequada dos resíduos orgânicos. Em relação aos resultados obtidos e às análises químicas, pode-se mencionar que o sistema de reator biológico foi o método que estabilizou mais rapidamente os resíduos. Quanto à qualidade do composto, nenhum dos sistemas de compostagem obteve um composto de boa qualidade para o seu ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The need to search for environmentally friendly solutions for solid waste disposal has become urgent, driven by rapid population growth and economic development. Composting is a traditional and sustainable tool of great importance for the treatment of the organic fraction of solid waste; processing organic waste originated from agricultural industry, agriculture, commerce and households, such as food scraps. This work deals with the treatment of food waste from restaurants, through an applied experimental research with three composting processing models (two industrial and one domestic). A co-composting with the addition of other structural waste, was developed and compared to the studied composting models. This study aims to obtain ways to accelerate and optimize the composting process, through the evaluation of biological degradation of solid waste parameters (pH, humidity, temperature, oxygen content, carbon / nitrogen ratio and quality of compost produced), contributing to the choise of the best method for proper disposal of organic waste. Regarding the results obtained and the chemical analysis, it can be mentioned that the bioreactor system is the method that quickly stabilized waste. As the quality of the compost, composting none of the systems obtained a good quality compost for use in agriculture. Some failures were observed in the methods, interfering with the development of the process. However, they exhibited moisture content, pH and DBO within the ideal range f... (Complete abstract click electronic access below) / Mestre

Orientador: Raquel Fernandes Pupo Nogueira / Coorientador: Maria Lúcia Arruda de Moura Campos / Banca:Arnaldo Alves Cardoso / Banca: Joao Flávio da Silveira Petruci / Banca: Pedro Sérgio Fadini / Banca: Anne Helene Fostier / Resumo: No estado de São Paulo, desde 2006, a queima da palha de cana-de-açúcar para colheita manual foi gradativamente substituída pela colheita mecanizada. Apesar dessa mudança na prática agrícola, a queima de biomassa no Brasil, seja esta intencional ou acidental, ainda é intensa, contribuindo para a emissão de uma diversidade de espécies gasosas e de material particulado para a atmosfera. Uma característica particular do Brasil é a elevada utilização de etanol como combustível, sendo que essa demanda vem aumentando dentro e fora do país, ocasionando uma maior emissão atmosférica de etanol e de espécies orgânicas correlatas, com consequências ainda pouco conhecidas. Neste contexto, este trabalho apresenta o primeiro estudo ao longo de 13 anos (2004 a 2016) de carbono orgânico dissolvido (COD) na água de chuva das cidades de Araraquara e Ribeirão Preto, localizadas numa região tipicamente agroindustrial do estado de São Paulo. As concentrações de metanol, etanol, formaldeído, acetaldeído, ácido fórmico e ácido acético foram determinadas em água de chuva, a fim de melhor compreender suas fontes, as possíveis oscilações sazonais e ao longo dos anos. A média ponderada pelo volume (MPV) de COD em água de chuva foi de 288 ± 17 μmol C L-1. As concentrações MPV no período seco (safra; abril a novembro) foram de 373 ± 29 μmol C L-1 (n = 485) sendo esta significativamente maior (teste-t, P = 0,05) do que aquela obtida no período chuvoso que abrange os meses de dezembro a março (180 ± 12 μmo... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In the state of São Paulo, since 2006, the burning of the sugar cane for manual harvesting has gradually been substituted by the mechanized harvest. Despite this change in agricultural practice, the biomass burning in Brazil, whether intentional or accidental, is still intense, contributing to the emission of a diversity of gaseous species and particulate matter into the atmosphere. A particular characteristic of Brazil is the intense use of ethanol as a fuel, and this demand has been increasing both inside and outside the country, resulting in a higher atmospheric emission of ethanol and correlates organic species, with consequences yet unknown. In this context, this work presents the first study over 13 years (2004 to 2016) of dissolved organic carbon (DOC) in the rainwater of the cities of Araraquara and Ribeirão Preto located in a typically agroindustrial region of the state of São Paulo. The concentrations of methanol, ethanol, formaldehyde, acetaldehyde, formic acid and acetic acid were determined in rainwater in order to better understand their sources, the possible seasonal fluctuations and yearly. The volume weighted average (VWA) of DOC in rainwater was 288 ± 17 μmol C L-1. VWA concentrations in the dry period (harvest; April to November) were 373 ± 29 μmol C L-1 (n = 485) and this was significantly higher (t-test, P = 0.05) than that obtained in the rainy season which covers the months from December to March (180 ± 12 μmol C L-1; n = 396). Despite the progressive e... (Complete abstract click electronic access below) / Doutor

Orientador: Mara Cristina Pessôa da Cruz / Coorientador: Flávia Fernanda Simili / Banca: Felipe Batistella Filho / Banca: Manoel Evaristo Ferreira / Resumo: O uso de indicadores é importante para avaliar mudanças na qualidade do solo em função de estratégias de manejo. O objetivo com este trabalho foi comparar o sistema integrado de lavoura-pecuária com sistemas de monocultivo de milho e de pecuária de corte nos seus efeitos em atributos químicos indicadores de qualidade do solo. Foram avaliados seis tratamentos principais, sendo dois sistemas de monocultivo (Zea mays; Urochloa brizantha cv marandu) e quatro sistemas de integração lavoura-pecuária: milho mais capim-marandu semeados simultaneamente; milho mais capim-marandu + herbicida nicosulfuron; milho mais capim-marandu semeado na adubação de cobertura do milho; milho mais capim-marandu semeado na linha e na entrelinha do milho + herbicida nicosulfuron. Os atributos do solo foram avaliados em amostras coletadas em duas profundidades, 0-0,10 e 0,10-0,20 m, e em três épocas durante um ano. O delineamento experimental foi em blocos casualizados (três) com parcelas sub subdivididas (profundidades/ épocas, respectivamente). Os indicadores avaliados foram carbono orgânico total, carbono da biomassa microbiana, carbono oxidável em solução de permanganato de potássio, índice de manejo do carbono, nitrogênio total, relação C:N do solo, nitrogênio da biomassa microbiana e relação C:N da biomassa microbiana do solo. Entre os sistemas de integração, a aplicação de nicosulfuron foi prejudicial na semeadura simultânea de milho e capim, uma vez que diminuiu o carbono da biomassa microbiana. ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The use of indicators is important to evaluate changes in soil quality due to management strategies. The objective of this study was to compare the integrated crop-livestock system with maize monoculture and beef cattle systems in their effects on chemical attributes indicating soil quality. Six main treatments were evaluated: two monoculture systems (Zea mays; Urochloa brizantha cv marandu) and four crop-livestock integration systems: maize plus marandu grass seeded simultaneously; maize plus marandu grass + nicosulfuron herbicide; maize plus marandu grass sown in maize cover fertilization; maize plus marandu grass seeded on the line and between maize + herbicide nicosulfuron. Soil attributes were evaluated in samples collected at two depths, 0-0,10 and 0,10-0,20 m, and at three times for one year. The experimental design was in randomized blocks (three) with sub subdivided plots (depths / seasons, respectively). The indicators evaluated were total organic carbon, microbial biomass carbon, oxidizable carbon in potassium permanganate solution, carbon management index, total nitrogen, soil C:N ratio, microbial biomass nitrogen and microbial biomass C:N ratio from soil. Among the integration systems, the application of nicosulfuron was detrimental in the simultaneous sowing of maize and grass, since it decreased the carbon of the microbial biomass. The corn monoculture presented the lowest concentration of nitrogen in the microbial biomass, compared to the treatments in which t... (Complete abstract click electronic access below) / Mestre

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Chemistry, 1982 / Includes bibliographical references. / by Lynda Gail Sturgeoff. / Ph. D. / Ph. D. Massachusetts Institute of Technology, Department of Chemistry

This study examines the use of MnO2 and KMnO4 as strong oxidants to remove specific recalcitrant organic compounds and COD from wastewater. These compounds are deemed as potential and more cost-effective treatment in encountering the challenge to remove Pharmaceuticals and Personal Care Products (PPCPs) and Endocrine Disrupter Compounds (EDCs) in wastewater to meet water reuse standard. The literature reviews concluded that both MnO2 and KMnO4 were able to remove recalcitrant organic compounds, such as 17α-ethynylestradiol (EE2), Bisphenol A (BPA), triclosan, and dye wastewater. Simple bench scale experiments were performed to investigate COD removal by utilizing MnO2 and KMnO4 to oxidize sewage water and supernatant in a continuously stirred tank reactor at the wastewaters’ natural pH (about pH 8). The results indicated that MnO2 was effective in removing COD of wastewater and not affected by the high content of suspended solids. The effectiveness of KMnO4 in removing COD of wastewater was masked by its ability to break down and solubilize particulate organic compounds. MnO2 application could not be mixed with the presence of other metal ions (or flocculants) as their presence may inhibit the efficiency of MnO2 oxidation. On the other hand, KMnO4 oxidation efficiency was not affected and even was enhanced by the presence of magnesium and calcium ions as flocculants.

The 207Pb and 119Sn NMR chemical shift were used to study the effect of temperature on Ph3MCl (M= Pb and Sn) adducts in the presence of 10% excess pyridine. The 207Pb and 119Sn chemical shift indicate a slow exchange at low temperatures below -90 0C and a significant exchange at higher temperatures above 10 0C. A plot of temperature against 207Pb or 119Sn chemical shift showed a curve with gentle slope at lower and a steep slope at higher temperatures. A good linear correlation (coefficient. of 0.95) between Hammett substituent constant and 207Pb or 119Sn chemical shift of para-substituted derivatives of Ph3MCl.py* (py* = NMe2, OMe, Me, Ph, H, Br, COPh and COMe; at -90 0C in CD2Cl2/CH2Cl2) was found. Both 207Pb and 119Sn chemical shift ranges are characteristic of five coordinate systems resolving into trigonal bipyramidal geometry as shown by X-ray crystal structures. New complexes of the type [CpFe(CO)(SnPh3)L] (L = PPh3, PBu3, PCy3, PMe3, P(NMe2)3, PMePh2, PMe2Ph, P(p-FC6H5)3, P(p-OMeC6H4)3, P(p-tolyl)3, P(OMe)3, and P(OPh)3 were synthesized by ultraviolet irradiation of [CpFe(CO)2(SnPh3)] and the appropriate phosphine or phosphite ligand. 57Fe NMR studies of the complexes showed an increasing linear relationship with Tolman’s steric parameter, whereas with Tolman’s electronic parameter the 57Fe chemical shift showed a decrease. The X-ray crystallographic profile of the selected new piano stool type complexes shows a significant correlation to the NMR data (solution state), i.e. Fe-Sn, Fe-P bond length and Sn-Fe-P bond angle against chemical shifts of 207Pb and 119Sn. Disubstituted complexes of the type [CpFe(SnPh3)L2] (L = PMe3, PMe2Ph, P(OMe)3 and P(OPh)3 were synthesized under similar conditions as monosubstituted compounds. The correlation trends between the NMR data and X-ray crystallographic profiles are similar to those found for monocarbonylated complexes. Tungsten phosphine complexes of the type [W(CO)5(PR3)] (prepared from [W(CO)6] under thermal conditions) and [W(CO)4(NCMe)(PR3)] (prepared from [W(CO)5(PR3)] by use of Me3NO-promoted decarbonylation) were synthesized and characterized by, among other methods X-ray diffraction techniques (R = Ph, p-tolyl, p-OMeC6H4, p-FC6H4, p-CF3C6H4, and NMe2). The tungsten complexes [W(CO)4(NCMe)(PR3)] react with [(dppp)Pt{C≡C-C5H4N}2] at room temperature to form new complexes of the type [(dppe)Pt{C≡C-C5H4N-W(CO)4(PR3)}2] which were characterized unambiguously by NMR spectroscopy. There is a fair correlation between 195Pt and 183W NMR chemical shifts and Tolman’s electronic parameter which indicates a fair influence by the substituents of the phosphorus atom on both metal centres. Tungsten complexes of the type [W(CO)4(NCMe)(L)] (L= PPh3, P(p-FC6H4)3, P(p-OMeC6H4)3, P(p-tolyl)3, P(p-CF3C6H4)3, PMePh2, and PPh2(C6F5) react with [(PPh3)2Rh(H)2(pytca)] (pytca = 2-(4-pyridyl)thiazole-4-carboxylate) to form new complexes of the type [(PPh3)2Rh(H)2(pytca)- W(CO)4(L)] under mild conditions. These complexes were characterized principally by NMR spectroscopy and X-Ray crystallography (L = P(p-tolyl)3). Crystallographic evidence was found for π-π-π interactions involving two phenyl rings, one of the two phosphines bonded to rhodium atom, one of the three phosphines bonded to tungsten and the pyridyl ring of the thiazole corboxylate group. A second π-π interaction is found between a thiazole and a phenyl ring of the phosphine ligand bonded to the rhodium atom. A fair correlation was found between the rhodium and tungsten chemical shift measured from this series of complexes as a result of varied paraphenyl substituent of phosphine ligand bonded to the tungsten atom. This therefore implies the possible existence of electronic communication between the two bridged metal centres.

Methods of collecting, concentrating, separating, and identifying organic compounds in natural water systems are presented. These methods were applied to a eutrophic reservoir (Hyrum Reservoir, Utah) and resulted in the identification of the following 27 volatile, organic compounds: Alcohols: methanol, ethanol, 1-propanol, isopropyl alcohol, 1-butanol, 2-butanol, isobutyl alcohol, tert-butyl alcohol, 1-pentanol, 2-methyl-l-butanol, methyl-1- butanol, 3-methyl-2-butanol, 2-methyl-2-butanol, 2-methyl-3-buten-2-ol, 1-penten-3-ol, 2-methyl-2-pentanol Ketones: acetone, methyl ethyl ketone, 4-methyl-3-penten-2-one Aldehydes: acetaldehyde, propanal, 2-buten-1-al Others: acetonitrile, ethyl acetate, pyridine, 3-methylpyridine, diethyl ether The concentration level of the following 13 compounds was established in the reservoir from October 1974 to January 1976: Alcohols: methanol, ethanol, propanol, isopropyl alcohol, 1-butanol, isobutyl alcohol, tert-butyl alcohol 2-methyl-2-butanol, 2-methyl-3-buten-2-ol Ketones: acetone, methyl ethyl ketone Others: acetonitrile, acetaldehyde The highest concentrations of organics were found in the late summer or early fall as the bloom of Aphanizomenon flos-aquae died and the level of bacterial fermentation increased. Other sources of organic compounds in the reservoir (besides fermentation) included compounds (acetonitrile and ethanol) at least partially produced by active algal growth and associated bacteria. Melting snowpack and mountain streams that feed the reservoir also contained organic compounds similar to those found in the reservoir, however at lower levels. Most of the compounds at low concentrations had no effect on the growth of certain algae tested, however there was some indication that certain organics may have increased the net growth of Aphanizomenon flos-aquae.