Orientador: Antonio Carlos Luz Lisbôa / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-19T18:01:21Z (GMT). No. of bitstreams: 1 Ferraz_DanielleLacerdaLupetti_M.pdf: 2035064 bytes, checksum: 6ca32474439698039670ca4037e4bfcf (MD5) Previous issue date: 2011 / Resumo: A crescente demanda de derivados de petróleo proporciona cada vez mais a necessidade desses produtos na sociedade atual. Este fato é reconhecido pelo desenvolvimento do país, com investimentos e desenvolvimentos em produtos energéticos e não energéticos oriundos do processamento do petróleo e, como consequência, são gerados grandes volumes de efluentes, em que os componentes fenólicos são presentes contaminantes comuns. Tratam-se de compostos tóxicos, carcinogênicos e que possuem boa solubilidade em água e baixa capacidade de biodegradação. Levando-se em conta esse aspecto, este estudo propôs mitigar os impactos ambientais utilizando o processo de adsorção em carvão ativado para remoção de fenóis. Para o desenvolvimento dessa pesquisa foi realizada uma revisão bibliográfica sobre o petróleo, algumas consequências geradas devido ao seu processamento, apresentando também técnicas de tratamento do efluente água fenólica, selecionando a adsorção como método mais eficiente e econômico para o tratamento, além do estudo experimental realizado para analisar a viabilidade técnica do tratamento, em que a caracterização do adsorvente e o conhecimento da dinâmica de adsorção são imprescindíveis para esse estudo. Os métodos de caracterização utilizados foram: análise granulométrica, umidade, massa específica real, bulk density, morfologia de superfície, área superficial, grupos funcionais, pH e análise elementar. Para um estudo mais abrangente dos fatores operacionais foi avaliada a zona de transferência de massa (ZTM) em relação à vazão de alimentação, indicando que a vazão com menor valor de ZTM foi de 3 mL min-1; foi estudado o efeito da temperatura de adsorção por banho infinito indicando que a melhor temperatura de operação, dentre as estudadas, foi de 20°C. Resultados obtidos pelo estudo mostraram que a adsorção de fenóis utilizando carvão ativado granular apresentou boas eficiências, em que a capacidade de adsorção de fenóis por unidade de massa de carvão ativado até o ponto de ruptura e saturação do leito foram 57,7 mg g-1 e 185,2 mg g-1 respectivamente para condição de vazão 3 mL min-1, granulometria do adsorvente 0,855 mm, temperatura ambiente, pH=10 e concentração de 4000 ppm em massa do efluente. Ainda, foi construído uma isoterma de adsorção e os dados de equilíbrio foram correlacionados utilizando os modelos de Langmuir e Freundlich, em que o modelo de Langmuir foi o que melhor representou os dados de equilíbrio no processo / Abstract: The increasing demand of petroleum derivative provides more and more need for these products in current society. This fact is recognized by the development of the country, with investments and developments in energy and non-energy products from the processing of petroleum and, therefore, has generated large volumes of effluent, in which the phenolic compounds are common contaminants. These are toxic compounds, carcinogens and that have good water solubility and low capacity for biodegradation. Taking this into account, this study proposed to mitigate environmental impacts using the adsorption process on activated carbon to remove phenols. For the development of this research, it was conducted a literature review on petroleum, some consequences generated due to processing, and also presented techniques for the treatment of the phenolic water, selecting adsorption as the most efficient and economic for the treatment beyond the experimental study undertaken to examine the technical feasibility of treatment, the characterization of the adsorbent and the knowledge of the dynamics of adsorption are instrumental to this study. The following methods were used: particle size analysis, moisture, real specific mass, bulk density, surface morphology, superficial area, functional groups, pH and elemental analysis. For a more comprehensive study of operational factors evaluated the mass transfer zone (MTZ) in relation to flow rate, indicating that the flow rate with a lower value of MTZ was 3 mL min-1; the effect of temperature infinite bath adsorption indicating that the best operating temperature, among those studied, was 20 °C. Results obtained by the study showed that the adsorption of phenols using granular activated carbon showed good efficiency in the phenol adsorption capacity per unit mass of activated carbon to the breakthrough point and saturation of the bed were 57,7 mg g-1 and 185,2 mg g-1 respectively for flow rate condition 3 mL min-1, adsorbent particle size of 0,855 mm, ambient temperature, pH=10 and 4000 ppm in mass concentration of the effluent. Still, it was built an adsorption isotherm and the equilibrium data were correlated using the Langmuir and Freundlich models, in which the Langmuir model was best represented the equilibrium process / Mestrado / Engenharia de Processos / Mestre em Engenharia Química

M.Tech. / In this study, ethylene vinyl acetate-fly ash (EVA-FA) composites were explored for the removal of phenols from water. The composites were prepared from EVA and untreated and acid treated fly ash via the melt-mixing technique using a rheomixer. The fly ash was characterised by X-ray fluorescence (XRF), X-ray diffraction (XRD) scanning electron microscopy (SEM) and Brunauer, Emmett and Teller (BET) surface area measurement. Fly ash is composed mainly of SiO2, Al2O3, CaO and Fe2O3. Modified fly ash gave a better specific surface area of 0.4180 m2/g, while 0.0710 m2/g was obtained for unmodified fly-ash due to the disintegration of the outer layer which resulted in smaller particles, hence a larger surface area. EVA-FA composites were prepared from fly ash loadings of 3 to 20% and further characterised by XRD, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and SEM. XRD showed successful incorporation of fly ash into the EVA matrix through the appearance of fly ash diffraction peaks on the EVA-FA composite diffraction pattern. The incorporation of fly ash into the EVA matrix resulted in an improvement in the thermal stability of EVA, but did not have an effect on the melting temperature of the composites. However, a decrease in crystallisation temperature was observed. SEM micrographs revealed uniform dispersion of fly ash particles in the polymer matrix. Adsorption studies were performed using p-chlorophenol (PCP), 2,4,6-trichlorophenol (TCP) and p-nitrophenol (PNP) as model pollutants. An increase in adsorption efficiency of EVA-FA composites was observed as fly ash loading was increased from 3 to 10%. Between 10 and 20% fly-ash loading the removal efficiencies remained constant. The effect of contact time, pH and initial concentration was investigated. Polymer composites prepared from unmodified fly ash resulted in a higher adsorption capacity of phenols. The maximum uptake of PCP was 0.18 mg/g and that for TCP was 0.19 mg/g over a pH range of pH 3 to 5 and after contact time of 8 h. However, the adsorption capacity of 0.30 mg/g for PNP was achieved at pH 5 after a period of 10 h. Equilibrium adsorption data were evaluated using Langmuir and Freundlich adsorption isotherm models. There was no significant difference in the correlation coefficients (R2) from both models for the adsorption of PCP and TCP. However, the equilibrium adsorption data for PNP were better described by the Langmuir adsorption isotherm model. The kinetics data were analysed by pseudo-first-order and pseudo-second-order kinetic models. The pseudo-second-order kinetics model gave better correlation coefficients (> 0.9) for the adsorption of the phenols and the amount adsorbed at equilibrium was comparable to that calculated from the pseudo-second-order equation. Desorption studies were performed using NaOH solution with varying concentrations (0.1 to 0.3 M) and the studies revealed that PNP was the most difficult to be desorbed. Approximately 75% of PNP was recovered while 82% of PCP and 84% of TCP were recovered.

In South Africa the genus, Eucalyptus plays an important role as a major economic component in the forest and mining sector. Unfortunately, this genus has problems due to damage by pests. The Eucalyptus snout beetle, Gonipterus scutellatus, feeds and defoliates the leaves of eucalypts. Plants produce secondary metabolites, which protects them against defoliation by insects and herbivores. This study focuses on the variations of total soluble phenolic content of nine Eucalyptus species between the species and within the species throughout the year. Total soluble phenols were quantified with the Folin-Ciocalteau reagent. There was a general increase in the concentration of total soluble phenols throughout the year. The content of total soluble phenols were generally higher compared to carbohydrates. This experiment needs to be done on a continuous basis so as to formulate a screening method for eucalypt species that are resistant to G. scutellatus. / Dissertation (M Inst Agrar (Sustainable Insect Management))--University of Pretoria, 2005. / Zoology and Entomology / unrestricted

This work presents the syntheses, photophysical and photochemical characterization of arylthio zinc phthalocyanines and their gold nanoparticle conjugates. Spectroscopic and microscopic studies confirmed the formation of the phthalocyanine-gold nanoparticle conjugates which exhibited enhanced photophysicochemical properties in comparison to the phthalocyanines. The studies showed that the presence of gold nanoparticles significantly lowered fluorescence quantum yields and lifetimes. However, this interaction did not restrict the formation of excited singlet and triplet states and hence the formation of singlet oxygen required for photocatalysis. The conjugates showed significantly higher singlet oxygen quantum yields and therefore enhanced photocatalytic activity compared to the phthalocyanines. The zinc phthalocyanines and their gold nanoparticle conjugates were successfully incorporated into electrospun polymer fibers. Spectral characteristics of the functionalized electrospun fibers indicated that the phthalocyanines and phthalocyanine-gold nanoparticle conjugates were bound and their integrity was maintained within the polymeric fiber matrices. The photophysical and photochemical properties of the complexes were equally maintained within the electrospun fibers. The functionalized fibers were applied for the photoconversion of 4-chlorophenol and Orange G as model organic pollutants. / Microsoft� Word 2010 / Adobe Acrobat 9.53 Paper Capture Plug-in

The thesis reports on fabricating alternative solid phase extraction (SPE) sorbents and colorimetric probes based on electrospun nanofibers for alkylphenols (APs). Hydroxyl methylated styrene [poly(co-styrene-CH₃OH)] and 3-oxobutanoate styrene [poly(co-styrene-OCOCH₃COCH₃)] copolymers were synthesized and fabricated into sorbent materials by electro-spinning/spraying. The fabricated morphologies consisting of bead free fibers, beaded fibers and particles were evaluated as SPE sorbents using batch experiments. Electropun fibers proved to be better sorbents as they exhibited extraction efficiency that exceeded 95% compared to 60% for beaded fibers and 40% for particles. In view to reduce sample and solvent volumes, smooth fibers were packed into pipette tips as SPE devices that yielded quantitative recoveries of APs from spiked wastewater samples. Recoveries ranged from 70% to 125% with LOD of 0.008, 0.01 and 0.1 μg mL⁻¹ for 4-tert octylphenol (4-t-OP), 4-octylphenol (4-OP) and 4-nonylphenol (4-NP) respectively, when using high performance liquid chromatography-fluorescence detector (HPLC-FLD). Furthermore, amino functionalised polydiacetylene polymers (PDAs), citrate capped gold (AuNPs) and silver nanoparticles (AgNPs) were evaluated as colorimetric probes for visual detection of APs. In colloidal studies, AuNPs probe showed a colour change from wine red to green upon introduction of analyte. UV-vis spectroscopy revealed the shifting of the surface plasmon resonance (SPR) peak from 525 nm to 729 nm induced by aggregation of AuNPs. For AgNPs probe, a colour change was observed from yellowish green to brown. Transmission electron microscopy (TEM) studies showed growth of AgNPs. A presumed oxidation of the analyte, forming an absorbing compound at 279 nm in both AgNPs and PDAs probes was also observed. For PDAs probe the colour change was from purple to pink. Concentrations as low as 30 μg mL⁻¹ were detectable in all colloidal based probes. Further colorimetric investigations were conducted with electrospun AuNPs-nylon 6 fiber mat. A colour change from purplish red to navy blue at concentrations of 1000 μg mL⁻¹ was observed. Electrospun AgNPs –nylon 6 fiber mat did not show a distinct colour change. High resolution scanning electron microscopy (HRSEM) revealed the analyte inducing the assembly of AuNPs and AgNPs as they covered the surface of the nanofiber mat. Electrospun nanofibers are a platform for analysis and thus tuning their chemistry will lead to sensitive and selective methods

Host-plant resistance is an important component of integrated pest management. Host resistance to phytophagous insects and mites based on chemical and morphological characteristics has been identified in various agronomic crops. The present study was undertaken to examine how variation in selected morphological and chemical characteristics of beach strawberry Fragaria chiloensis (L.) Duchesne affects population parameters of the twospotted spider mite Tetranychus urticae Koch. The results from this study show that clones of F. chiloensis and the cultivar "Totem" vary in suitability for the twospotted spider mite. Selected clones of F. chiloensis and the cultivar "Totem" differed also in the following foliar characteristics: densities of glandular and nonglandular trichomes and concentrations of total and catechol-based phenolics. In contrast, qualitative analysis of phenolic compounds, determined via HPLC, revealed a close similarity between F. chiloensis and F. x ananassa (cultivated strawberry) and among selected clones of F. chiloensis. Mite oviposition was negatively correlated with densities of glandular and nonglandular trichomes and concentrations of total foliar phenolics. In spite of these significant relationships, mite oviposition was best predicted by a combination of interacting plant characteristics rather than by any individual characteristic. Entrapment by sticky exudates from glandular trichomes appears to explain the negative relationship between mite survival and density of glandular trichomes. Spider mite development was negatively related to concentrations of foliar phenolics; twospotted spider mite development is delayed on leaves with high concentrations of phenolics. The correlation between mite development and foliar phenolics was greater when catechol-based phenolics were used. / Land and Food Systems, Faculty of / Graduate

The original purpose of this investigation was to prepare a series of diketones. However, since considerable difficulty was encountered in the preparation of these diketones, attention was shifted to a study of the Friedel-Craft reactions of phenolic ethers and to the reaction between phenolic ethers and dicarboxylic acids with boron trifluoride as a catalyst.

Au cours de cette thèse, plusieurs nouvelles méthodes d'arylation de nucléophile (oxygéné, azoté et carboné) ont été mises au point ainsi qu'une étude mécanistique. Dans le cadre du projet ANR, nous avons réalisé des travaux dans ce domaine dans le laboratoire du Dr Anny Jutand à L'ENS Paris. D'un point de vue général, nous pouvons donc dire que nos méthodes se situent bien en phase avec les critères de la réglementation européenne visant à diminuer l'impact des produits chimiques sur l'environnement (REACH) par la recherche de nouvelles voies de synthèse moins toxiques et moins polluantes. Travaux en cours et perspectives : Par rapport aux réactions faisant intervenir des catalyseurs au palladium, celles impliquant le cuivre ont très peu été étudiées du point de vue de leur mécanisme. Les premiers travaux concernant le mécanisme de l'arylation de nucléophiles catalysé au cuivre ont débuté depuis seulement quelques années et ont conduit à environ une dizaine de publications. Malgré quelques avancées significatives, beaucoup reste à faire. / In this thesis, several new methods of nucleophilic arylation (oxygen, nitrogen and carbon) were developed and a mechanistic study. As part of the ANR project, we have carried out work in this field in the laboratory of Dr. Anny Jutand at ENS Paris. From a general point of view we can say that our methods are well in line with the requirements of European regulations to reduce the impact of environmental chemicals (REACH) by the search for new synthetic routes less toxic and less polluting. Work in Progress and prospects : Compared to reactions involving palladium catalysts, those involving copper have been studied very little in terms of their mechanism. Early work on the mechanism of arylation of nucleophiles catalyzed copper began last few years and led to about a dozen publications. Despite some significant advances, much remains to be done.

Whole grain and bran samples of two Malawian sorghums, Phatafuli, (a brown-coloured condensed tannin variety) and Shabalala, (a white-coloured condensed tannin-free variety) were analysed for their content of total phenols, condensed tannins and antioxidant activities. The effect of oxidizing conditions during extraction, and the storage stability of a freeze-dried crude phenolic extract (CPE) from the condensed tannin sorghum bran as influenced by packaging, storage temperature and length of storage, in relation to its content of total phenols, condensed tannins and antioxidant activity was also investigated. Antioxidant activity of the CPE, in comparison with tertiary butyl hydroquinone (TBHQ), was then evaluated in sunflower oil at concentrations of 1000, 1500 and 2000 ppm in the absence or presence of ferric ions at 2.2 and 4.4 ppm in the dark at 65oC.Progression of oxidation was monitored by measurement of peroxide values (PV) and anisidine values (AV) during a 14-day storage period. Phatafuli contained higher content of total phenols and antioxidant activity than Shabalala both in the whole grain and the bran, probably due to the presence of condensed tannins in Phatafuli sorghum, which were not detected in Shabalala sorghum. For both sorghum varieties, the bran contained higher levels of total phenols and antioxidant activity than the whole grain, confirming that phenolic compounds in sorghum are largely concentrated in the bran. Antioxidant activities of the sorghum varieties correlated highly with their total phenol and condensed tannin contents, suggesting that the phenolic compounds were largely responsible for the antioxidant activities of the sorghum grains. Bubbling of oxygen into the liquid crude phenolic extract did not have any significant effect on the parameters tested. Similarly, vacuum-packed samples did not differ significantly in the parameters tested from the samples that were not vacuum-packed. CPE samples stored at –20oC had significantly higher levels of total phenols, condensed tannins and antioxidant activity than those stored at 25oC during some days of storage. Storage time was however the major factor influencing the levels of total phenols, condensed tannins and antioxidant activity of the CPE from Phatafuli sorghum during storage, which suggested that CPE from condensed tannin sorghum bran might need to be used shortly after extraction to ensure optimum antioxidant activity. There was an insignificant correlation between the antioxidant activities of the CPE and their phenolic contents during storage, which could have been due to the formation of new compounds with a lower antioxidant capacity. The CPE inhibited oxidation of sunflower oil as shown by lower peroxide values and anisidine values compared to control samples. The CPE was however less effective in reducing peroxide values compared to TBHQ, but was similar to TBHQ in reducing anisidine values. In the presence of ferric ions, the CPE appeared to be less effective in reducing peroxide values compared to TBHQ, but appeared to be more effective than TBHQ in reducing anisidine values. The results showed that the tannin sorghum bran CPE appeared to act as both lipid radical scavengers and metal chelators. The CPE however imparted colour to the sunflower oil, which could limit its application as a natural antioxidant in edible oils. / Dissertation (MSc(Agric) Food Science and Technology)--University of Pretoria, 2008. / Food Science / unrestricted

Orientador: Jose Augusto Rosário Rodrigues / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-24T08:17:01Z (GMT). No. of bitstreams: 1 Carvalho_PauloSergiode_D.pdf: 14146737 bytes, checksum: cce704fa63bb067ebc25618dac57ceb6 (MD5) Previous issue date: 2013 / Resumo: Este trabalho descreve uma metodologia para a síntese de 1,2- e 1,4-benzoquinona-monocetais através da oxidação de fenóis contendo uma cadeia hidróxi-alquílica lateral promovida por reagentes de iodo(III) hipervalente. 3-Hidróxi-?-metil-benzenopropanol e três derivados metoxilados foram preparados a partir dos respectivos benzaldeídos. Oxidações do 3-hidróxi-?-metil-benzenopropanol com um equivalente de diacetato de iodobenzeno (IBDA) ou [bis(trifluoroacetóxi)iodobenzeno] (BTIB) em diversos solventes não renderam o croman-6-ol esperado, mas apenas materiais poliméricos marrons. Entretanto, resultados interessantes foram obtidos das oxidações dos benzenopropanóis com dois equivalentes de IBDA em metanol ou 2,2,2-trifluoroetanol (TFE). Em metanol, 4,4-dimetóxi-cicloexa-2,5-dienonas e 6,6-dimetóxi-cicloexa-2,4-dienonas foram os produtos principais, enquanto que, em TFE, ciclizações da cadeia hidróxi-alquílica lateral não-rígida originaram monocetais semicíclicos de 1,2- e 1,4-benzoquinonas como produtos principais. A oxidação do 3-hidróxi-?-metil-4-metóxi-benzenopropanol em metanol rendeu um dímero de Diels-Alder mediante a cicloadição da respectiva cicloexa-2,4-dienona. As sínteses desses monocetais semicíclicos são importantes por se tratarem dos primeiros exemplos de cetais derivados de cromanóis obtidos por oxidações de fenóis contendo uma cadeia lateral não-rígida. A parte final do trabalho descreve as primeiras etapas de uma síntese do (S)-6-benzilóxi-2,5,7,8-tetrametil-croman-2-carbaldeído, proposta com base na metodologia desenvolvida. A síntese desse heterociclo representaria uma nova síntese formal da vitamina E (?-tocoferol). / Abstract: A methodology to the synthesis of 1,2- and 1,4-benzoquinone semicyclic monoketals through the oxidation of phenols bearing a hydroxy-alkyl side chain promoted by hypervalent iodine(III) reagents is described. 3-Hydroxy-?-methyl-benzenepropanol and three of its methoxy derivatives were prepared from the respective benzaldehydes. Oxidations of 3-hydroxy-?-methyl-benzenepropanol with one equivalent of iodobenzene diacetate (IBDA) or [bis(trifluoroacetoxy)iodobenzene] (BTIB) in a variety of solvents did not furnish the expected chroman-6-ol; instead, only red-brownish polymeric materials were produced. However, better results were achieved from the oxidations of the benzenepropanols by two equivalents of IBDA in methanol or 2,2,2-trifluoroethanol (TFE) as solvent. In methanol, 4,4-dimethoxy-cyclohexa-2,5-dienones and 6,6-dimethoxy-cyclohexa-2,4-dienones were the major products, whereas in TFE, cyclizations of the nonrigid hydroxy-alkyl side chain took place to furnish 1,2- and 1,4-benzoquinone semicyclic monoketals as main products. The oxidation of the 3-hydroxy-4-methoxy derivative in methanol yielded only a Diels-Alder dimer by the cycloaddition of the unstable intermediate cyclohexa-2,4-dienone. The syntheses of the semicyclic monoketals described here represent an important achievement since these are the first examples of semicyclic ketals related to chromanols obtained by the oxidation of phenols having a nonrigid hydroxy-alkyl side chain. The final part of this work describes the initial efforts towards the synthesis of (S)-6-benzyloxy-2,5,7,8-tetramethyl-chroman-2-carbaldehyde, proposed on the basis of the developed methodology. The synthesis of this heterocyclic compound would represent a new formal synthesis of vitamin E (?-tocopherol). / Doutorado / Quimica Organica / Doutor em Ciências