Thèses : « Phenols compounds »

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Zhu, Fan, et 朱帆. « Interactions of carbohydrates with phenolic compounds ». Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2010. http://hub.hku.hk/bib/B45584710.

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Rubió, Piqué Laura. « Phenol-enriched olive oil with its own phenolic compounds and complemented with phenols from thyme : a functional food development model ». Doctoral thesis, Universitat de Lleida, 2014. http://hdl.handle.net/10803/146133.

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L'enriquiment de l’oli d'oliva amb els seus propis fenols esdevé una estratègia interessant per augmentar i normalitzar la ingesta diària d’hidroxitirosol sense augmentar el consum calòric. No obstant això, olis amb alt contingut fenòlic proporcionen un gust amarg que podria provocar rebuig entre els consumidors. A més, altes dosis d'hidroxitirosol podria tenir una acció pro-oxidant. En aquesta tesi es va plantejar l'estratègia d'enriquiment d’un oli d'oliva no només amb els seus propis fenols, sinó amb fenols complementaris d'herbes aromàtiques, concretament de farigola, amb la hipòtesi de que apart de proporcionar millores en l'estabilitat de l'oli i l'acceptació dels consumidors, també podria aportar beneficis addicionals per a la salut. Un cop desenvolupat l'oli d'oliva enriquit en fenols, es va avaluar la biodisponibilitat dels fenols mitjançant mètodes in vitro i in vivo, avaluant possibles interaccions o sinergies entre ambdues fonts fenòliques.
El enriquecimiento de aceite de oliva con sus propios fenoles se convierte en una estrategia interesante para aumentar y normalizar la ingesta diaria de hidroxitirosol sin aumentar el consumo calórico. Sin embargo, aceites con alto contenido fenólico tienen un sabor amargo que podría provocar rechazo entre los consumidores, y además sus altas dosis de hidroxitirosol podría tener una acción pro-oxidante. En esta tesis se planteó la estrategia de enriquecimiento de aceite de oliva no sólo con sus propios fenoles, sino con fenoles complementarios de hierbas aromáticas, concretamente tomillo, con la hipótesis de que no sólo podría proporcionar mejoras en la estabilidad del aceite y la aceptación de los consumidores, sino que podría aportar beneficios adicionales para la salud. Una vez desarrollado el aceite de oliva enriquecido se evaluó la biodisponibilidad de los fenoles mediante métodos in vitro e in vivo, evaluando posibles interacciones o sinergias entre ambas fuentes fenólicas.
The enrichment of olive oil with its own phenolic compounds becomes an interesting strategy to increase and standardize the daily intake of hydroxytyrosol without increasing the caloric intake. Concerning olive oils with high phenolic content, however, they have a bitter taste, which could promote a refusal among consumers, and contain high doses of hydroxytyrosol that could have a pro-oxidant action. In this context, the strategy of enriching olive oil not only with its own phenolics but also with complementary phenols from aromatic herbs was outlined in this thesis with the hypothesis that it could not only improve olive oil stability and consumers’ acceptation but also provide additional health benefits. In this thesis a phenol-enriched olive oil was developed using the aromatic herb of thyme, and the bioavailability of the phenolic compounds was assessed, evaluating possible interactions or synergies between both sources through in vitro and in vivo approaches.

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Bourne, Thomas Franklin. « Biodegradation of keratins and phenolic compounds ». Diss., Georgia Institute of Technology, 1993. http://hdl.handle.net/1853/25403.

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Semple, Kirk Taylor. « The biodegradation of phenols by a eukaryotic alga ». Thesis, University of Newcastle Upon Tyne, 1994. http://hdl.handle.net/10443/374.

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Axenic cultures of Chiamydomonas ulvaensis [CCAP 11/58], Scenedesmus brasiliensis [CCAP 276/1 B] and Ochromonas danica [0CAP933/28] were screened for their ability to grow on and remove phenol from their incubation media. Neither C. ulvaensis nor S. brasiliensis removed the phenol substrate as rapidly as 0. danica which is a nutritionally versatile chrysophyte. 0. danica was found to grow on phenol and p-cresol as the sole C-source at concentrations up to 4mM in cultures grown in both photoheterotrophic and heterotrophic conditions. The alga would not grow on cresols or xylenols unless phenol was present. Oxygen uptake and turnover studies confirmed that the enzymes involved in phenolic catabolism were inducible and that the organism showed a decrease in activity resulting from the position and number of the methyl substituents on the aromatic ring. [U- 14C]Phenol was completely mineralised with some 65% of the 14C-label appearing as 14CO2, approximately 12% remaining in the aqueous medium and the rest accounted for in the biomass. Analysis of the biomass showed that 14C-label had been incorporated into the protein, nucleic acid and lipid fractions; phenol carbon is thus unequivocally assimilated by the alga. Phenol-grown cultures of 0. danica converted phenol to catechol which was further metabolised by the meta cleavage pathway. 2-Hydroxymuconic semialdehyde and pyruvate, characteristic products of meta cleavage, were found in incubations of catechol with cell-free extracts of phenol-grown cells together with the appropriate enzyme activities. This is , as far as I am aware, the first definitive identification of the meta cleavage pathway for aromatic ring degradation in a eukaryotic microorganism.

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Bifulco, Laura. « Development of electrochemical and microbial sensing systems for detection of phenolic compounds ». Thesis, Cranfield University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.269525.

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Khadambi, Tshiwela Norah. « Antimicrobial properties of phenolic compounds from sorghum ». Pretoria : [s.n.], 2005. http://upetd.up.ac.za/thesis/available/etd-03022007-164705.

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Alu'datt, Muhammad Hussein. « Phenolic compounds in oil-bearing plants and their interactions with oilseed protein isolates ». Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=102950.

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Oil-bearing plants are important sources of edible oil and proteins; they have attracted attention recently because of their antioxidant, antimicrobial and anti-inflammatory properties. The objective of this work was to investigate the nature of phenolic compounds in oil-bearing plants and the effects of phenolic compounds on protein isolates from soybean and flaxseed. Proteins were isolated from full-fat and defatted soybean and flaxseed using sodium hydroxide extraction and isoelectric precipitation. Free phenolic compounds were extracted from the oil-bearing plants and protein isolates using methanol; for bound phenolic compounds the oil-bearing plants and proteins were subjected to basic and acidic hydrolysis followed by methanol extraction. Total free and bound phenolic compounds were determined by spectrophotometric analysis. Reversed phase-HPLC was used for separation of individual phenolic compounds, which were identified by mass spectrometry (MS). Molecular characteristics and biological properties of the protein isolates were studied using RP-HPLC, polyacrylamide gel electrophoresis (PAGE) and MS. Thermal and gelation properties of protein isolates were investigated using differential scanning calorimetry (DSC) and rheometry. Generally, bound phenolic compounds (20%-30% of total phenolic content) were higher in protein isolates from flaxseed than in protein isolates from soybean (10%-20% of total phenolic content). With flaxseed protein isolates, removal of phenolic compounds showed little effect on the electropherotic behavior of the proteins or the protein subunits. Native-PAGE. SDS-PAGE and RP-HPLC for the peptides profiles of hydrolyzed protein isolates from both full-fat and defatted soybean revealed the removal of free and bound phenolic compounds affect on the biological properties of protein isolates. Removal of free and bound phenolic compounds affected the thermal stability and gelation properties of protein isolates from flaxseed and soybean.

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Lu, Junhe. « Fundamental studies of the halogenation of phenolic compounds during water chlorination / ». Thesis, Connect to this title online ; UW restricted, 2007. http://hdl.handle.net/1773/10197.

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Mafatle, Tsukutlane J. P. « Homogenous and heterogenous catalytic activity of metallophthalocyanines towards electrochemical detection of organic compounds ». Thesis, Rhodes University, 1998. http://hdl.handle.net/10962/d1004974.

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Cysteine plays an important role in many biological and pharmaceutical systems. Therefore, in view of its importance, it is essential to find means of detecting it at the lowest possible levels. In this regard, electrochemical techniques have been found to be capable of detecting analytes even at micro levels. However, electrochemical determination of cysteine occurs at a very high potentials. These overpotentials makes quantitative analysis or detection of cysteine difficult at most conventional carbon electrodes. On platinum electrode, the oxidation of cysteine has been reported to occur in the potential range 0.7 to 1.45 V (vs NHE). Therefore, the object of this investigative study has been to find an active complex that could replace platinum and other expensive metals as electrodes. Such a complex should also be capable of reducing the potential at which the oxidation of cysteine occurs on carbon electrodes. As a result, this manuscript gives a full report on the investigative study of electrocatalytic activity of molybdenum phthalocyanine complexes towards detection of cysteine. Molybdenum phthalocyanine, OMo(OH)Pc, and its tetrasulfonated derivative, [OMo(OH)TSPc]⁴⁻ were successfully used to reduce the potential needed to initiate the oxidation of cysteine on carbon paste electrodes (CPE). The oxidation of cysteine on CPE modified with [OMo(OH)Pc]⁴⁻ was found to occur at 0.29 V (vs Ag/AgCl), and in the presence of [OMo(OH)TSPc]⁴⁻ species in solution the oxidation occurred at 0.33 V (vs Ag/AgCl). Molybdenum, in the oxidation states of Mo(IV), Mo(V) and Mo(VI), is found in biological systems as an essential trace element, participating in a number of enzymatic reactions, where it is believed to be coordinated to sulphur-containing ligands in many molybdenum enzymes. This therefore explains why molybdenum phthalocyanines were employed in electroanalytical detection of sulphur containing amino acid, cysteine. Electrochemical methods have also been successfully used in detection of environmental pollutants such as phenolic compounds. Phenolic compounds are oxidised at readily accessible potentials. However, like cysteine, there are problems associated with the electrochemical detection of these important environmental pollutants. Their electrooxidation is known to form dimeric and/or polymeric oxidation products which adsorb onto the electrode surface, thus -videactivating it. Therefore, to address this problem, cobalt phthalocyanine (CoPc) and its tetrasulfonated derivative, [CoTSPc]⁴⁻ were employed in electrocatalytic detection of phenolic compounds. These complexes were found to increase the anodic peak currents for the oxidation of o-cresol, m-cresol, p-cresol, phenol, 2-chlorophenol and 4-chlorophenol. In addition, CoPc deposited onto the glassy carbon electrode improved the stability of the electrode, by reducing electrode poisoning caused by the electrooxidation products of the mentioned phenolic compounds. The potential at which the oxidation occurred and the current response of individual phenolic compounds depended on the degree of substitution and the type of substituent on the phenol molecule. In general, the current response was found to be lower for chlorinated phenols compared with the cresols and phenol. To establish the role of the central metal in the catalytic process, comparison of the electrocatalytic activity of some of the first row transition metal phthalocyanines, for the detection of mono-substituted phenolic compounds, showed the following trend: Co⁽¹¹⁾ > Mn⁽¹¹⁾ > Fe⁽¹¹⁾Pc > Ni⁽¹¹⁾Pc > Cu⁽¹¹⁾Pc > H₂Pc > Zn⁽¹¹⁾Pc > Bare GCE. A report is also given on electrocatalysis using [CoTSPc]⁴⁻ electrochemically deposited on the glassy carbon electrode. This was also found to enhance the anodic peak currents for the oxidation of all phenolic compounds. A report on the effects of scan rate, operating potential, analyte concentration and other variables is also given.

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SIAHAAN, TERUNA JAYA. « PREPARATIONS AND REACTIONS OF CRESOL DIANIONS AND DIMETHYLPHENOL TRIANIONS (ANISOLE, ALKYL PHENOL, CYCLOPHANE) ». Diss., The University of Arizona, 1986. http://hdl.handle.net/10150/183846.

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With n-BuLi/t-BuOK (Lochmann's base), protons are removed from the hydroxyl and methyl groups of cresols to give cresol dianions in yields of 85% (o), 95% (m), and 40% (p). These dianions react with alkyl halides, MeSiCl, Bu₃Sn Cl, CO₂, and oxidizing agents at carbon only, and with dialkyl sulfates at both carbon and oxygen. Thus phenol derivatives bearing primary alkyl groups can be prepared from the corresponding methylphenol via cresol dianions. Dimethylphenol trianions were prepared with Lochmann's base from all six isomers of dimethylphenol. 3,5-Dimethylphenol trianion was prepared in the best yield (80%); 2,3-, 2,4-, 2,5-, 2,6-, and 3,4-dimethylphenol trianions were prepared in 19.5%, 19%, 52%, 36%, and 44% yields, respectively. The common side products were dianions and tetraanions (in the latter, the fourth proton was usually pulled from the ring ortho to oxygen). These trianions were reacted with dimethyl sulfate to give anisole derivatives. 3,5-Dimethoxytoluene monoanion was reacted with n-BuBr to give a mixture of O,O'-dimethylolivetol (40%) and 4-butyl-3,5-dimethoxytoluene (34%).

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Kalili, Kathithileni Martha. « Application of comprehensive 2-dimensional liquid chromatography for the analysis of complex phenolic fractions ». Thesis, Stellenbosch : University of Stellenbosch, 2009. http://hdl.handle.net/10019.1/2420.

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Thesis (MSc (Chemistry and Polymer Science))--University of Stellenbosch, 2009.
ENGLISH ABSTRACT: The separation of apple, cocoa and green tea phenolic compounds by comprehensive 2-dimensional liquid chromatography (2-D-LC) has been studied. In the first dimension, phenolic compounds were separated according to polarity by hydrophilic interaction chromatography (HILIC) on a diol stationary phase with a mobile phase containing acetonitrile, methanol, acetic acid and water. Gradient reversed-phase (RP) LC using a C18 column with fluorescence detection was employed in the second dimension to separate compounds according to hydrophobicity. Compounds were identified using negative electrospray ionisation mass spectrometry (ESI-MS) coupled to both HILIC and RP separations. The coupling of HILIC and RP separations proved to be especially beneficial since this provided simultaneous information on both the polarity and hydrophobicity of phenolics. The low degree of correlation (r2 < 0.21) between the two LC modes afforded peak capacities in excess of 3000 for the off-line method. An on-line method was also developed utilizing a short, small particle-packed column to provide fast separation in the second dimension. A 1 mm i.d. column was used in the first dimension for the on-line system to reduce injection volumes onto the second dimension column. A significantly lower practical peak capacity was measured for the on-line system, due largely to the reduction in second dimension peak capacity. On the other hand, analysis could be performed in an automated fashion using the online system reducing the risk of sample alteration and guaranteeing better operation reliability and reproducibility. Especially the off-line comprehensive HILIC × RP-LC method developed demonstrated its utility in the analysis of various groups of phenolic compounds including proanthocyanidins, phenolic acids, flavonols and flavonol conjugates in a variety of natural products.
AFRIKAANSE OPSOMMING: Die skeiding van fenoliese komponente in appel, kakao en groen tee is deur middel van ‘comprehensive’ 2-dimensionele vloeistof chromatografie (2-D-LC) bestudeer. Hidrofiliese interaksie chromatografie (HILIC) is gebruik om die fenoliese komponente in die eerste dimensie te skei op grond van polariteit, deur gebruik te maak van ‘n diol stationêre fase en mobiele fase bestaande uit asetonitriel, metanol, asynsuur en water. ‘n Gradiënt omgekeerde fase (RP) LC analisie op ‘n C18 kolom met fluorosensie deteksie is in die tweede dimensie gebruik om fenole volgens hidrofobisiteit te skei. Negatiewe elektrosproei-ionisasie massa spektometrie (ESIMS) gekoppel aan HILIC en RP skeidings is gebruik vir identifikasie van fenole. Die koppeling van HILIC en RP skeidings veral voordelig deurdat dit gelyktydige informasie verskaf het oor die polariteit sowel as die hidrofobisiteit van die fenoliese komponente. Die lae graad van korrelasie (r2 < 0.21) tussen die twee LC metodes was verantwoordelik vir piek kapasiteite bo 3000 vir die af-lyn metode. ‘n Aanlyn metode was ontwikkel deur gebruik te maak van ‘n kort, klein partikel gepakte kolom om vinnige skeiding in die tweede dimensie te verseker. 1 mm i.d. kolom was gebruik in die eerste dimensie vir die aanlyn sisteem om die inspuit volume op die tweede dimensie kolom te verminder. Aansienlike laer praktiese piek kapasiteit was gemeet vir die aanlyn sisteem, grootliks toegeskryf aan die reduksie in die tweede dimensie piek kapasitiet. Aan die ander kant, analise kan geoutomatiseerd uitgevoer word deur gebruik te maak van die aanlyn sisteem, wat monster alterasie, beter betroubaarheid en reproduseerbaarhied verseker. Veral die ontwikkelde af-lyn ‘comprehensive’ HILIC × RP-LC metode toon demonstreerbare voordele vir die analiese van verskeie groepe fenoliese komponente, insluitende proantosianiede, fenoliese sure, flavonole en gekonjugeerde flavonole in ‘n verskeidenheid natuurlike produkte.

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Chiang, Sheau-Yun. « Reductive dechlorination of chlorinated phenols in methanogenic wetland sediment slurries ». Diss., Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/21281.

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Lathioor, Edward Camiel. « Inter- and intramolecular phenolic hydrogen atom abstraction by aromatic ketone triplets / ». *McMaster only, 2001.

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Makgae, Mosidi Elizabeth. « Environmental electrochemistry of organic compounds at metal oxide electrodes ». Thesis, Stellenbosch : Stellenbosch University, 2004. http://hdl.handle.net/10019.1/49947.

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Dissertation (PhD)--Stellenbosch University, 2004.
ENGLISH ABSTRACT: This study investigates the electrochemical oxidation of phenol. Phenol is a major toxin and water pollutant. In addition, during water treatment it reacts with chlorine to produce carcinogenic chlorophenols. lts treatment down to trace levels is therefore of increasing concern. For this purpose, dynamically stable anodes for the breakdown of phenols to carbon dioxide or other less harmful substances were developed and characterized. The anodes were prepared from mixed oxides of tin (Sn) and the precious metals ruthenium (Ru), tantalum (Ta) and iridium (Ir), which in tum were prepared using sol-gel techniques. This involved dip-coating the aqueous salts of the respective metals onto titanium substrates and heating to temperatures of several hundreds of degree Celsius. The properties of these mixed oxide thin films were investigated and characterized using thermal gravimetric analysis (TGA), scanning electron microscopy (SEM), atomic force microscopy (AFM), elemental dispersive energy X-ray analysis (EDX), X-ray diffraction (XRD), Rutherford backscattering spectrometry (RBS), particle induced X-ray emission (PIXE) and electrochemical measurements. A variety of different electrode materials including Til Sn02-Ru02-Ir02, Ti/Ta20s-Ir02 and Ti/RhOx-Ir02 were developed and tested for their potential as oxidation catalysts for organic pollutants in wastewaters. Depending on the anode type, phenol was found to be electrochemically degraded, to different extents, on these surfaces during electrolysis. It was however found that the oxidation rate not only depended on the chemical composition but also on the oxide morphology revealed, resulting from the preparation procedure. The Ti/SnOz-Ru02-Ir02 film was found to be the most efficient surface for the electrolytic breakdown of phenol. This film oxidized phenol at a potential of 200 mV vs Ag/AgC!. The activity of the catalytic systems was evaluated both on the basis of phenol removal efficiency as well as the kinetics of these reactions. Phenol removal efficiency was more than 90% for all the film surfaces prepared and the rate of the reaction followed first order kinetics. A pathway for the electrochemical degradation of phenol was derived using techniques such as HPLC to identify the breakdown products. These pathway products included the formation of benzoquinone and the further oxidation of benzoquinone to the carboxylic acids malic, malonic and oxalic.
AFRIKAANSE OPSOMMING: Die onderwerp van hierdie studie is die elektrochemiese oksidasie van fenol deur nuwe gemengde-oksied elektrodes. Fenol is 'n belangrike gifstof en besoedelingsmiddel in water. Daarbenewens kan fenolook met chloor reageer tydens waterbehandeling om sodoende karsinogeniese chlorofenole te vorm. Dit is dus belangrik dat metodes ondersoek word wat die konsentrasie van fenol in water verminder. Hierdie studie behels die bereiding en karakterisering van nuwe dinamiese stabiele anodes (DSA) vir die afbreek van fenol tot koolstofdioksied en ander minder gevaarlike verbindings. Hierdie nuwe anodes is berei vanaf die gemengde-okside van die edelmetale tin (Sn), ruthenium (Ru), tantalum (Ta) en iridium (Ir), met behulp van sol-gel tegnieke. Die finale stap in die bereiding behels kalsinering van die oksides by temperature van "n paar honderd grade Celsius. Hierdie nuwe elektrodes is later gebruik om die oksidasie van fenol te evalueer. Die gemengde-oksied dunlae/anodes IS d.m.v. die volgende analitiesetegnieke gekarakteriseer: termiese-gravimetriese analise (TGA), skandeerelektronmikroskopie (SEM), atoomkragmikroskopie (AFM), elementverstrooiingsenergie- X-straalanalise (EDX), X-straaldiffraksie (XRD), Rutherford terug-verstrooiingspektroskopie (RBS), partikel-geinduseerde X-straal emissie (PIXE), en elektrochemiese metings. 'n Verskeidenheid elektrodes van verskillende materiale is berei en hul potensiaal as oksidasie-kataliste vir organiese besoedelingsmiddels in afloopwater bepaal. Hierdie elektrodes het die volgende ingesluit: Ti/Sn02-Ru02-Ir02, Ti/Ta20s-Ir02 en Ti/RhOx-Ir02. Gedurende elektrolise is fenol elektrochemies afgebreek tot verskillende vlakke, afhangende van die tipe elektrode. Die oksidasietempo het egter nie alleen van die chemiese samestelling van die elektrode afgehang nie, maar ook van die morfologie van die okside, wat op hulle beurt van die voorbereidingsprosedure afgehang het. Daar is bevind dat die Ti/Sn02-Ru02-Ir02 elektrode die mees effektiewe oppervlakke vir die afbreek van fenol is. Hier het die oksidasie van fenol by 'n potensiaal van 200 mV plaasgevind. Die aktiwiteite van die katalitiese sisteme IS bepaal op grond van hulle fenolverwyderingsdoeltreffendheid. Die kinetika van die reaksies is ook bepaal. Al die elektrodes het >90% fenolverwyderingsdoeltreffendheid getoon en die reaksietempos was van die eerste-orde. Deur van analitiese tegnieke soos hoëdrukvloeistofchromatografie (HPLC) gebruik te maak is die afbreekprodukte van fenol geïdentifiseer en 'n skema vir die elektrochemiese afbreek van fenol uitgewerk. Daar is bevind dat bensokinoon gevorm het, wat later oksidasie ondergaan het om karboksielsure te vorm.

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Oputu, Ogheneochuko Utieyin. « Advanced oxidation process using ozone/heterogeneous catalysis for the degradation of phenolic compounds (chlorophenols) in aqueous system ». Thesis, Cape Peninsula University of Technology, 2016. http://hdl.handle.net/20.500.11838/2510.

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Thesis (DTech (Chemistry))--Cape Peninsula University of Technology, 2016.
The use of ozone as an advanced oxidation process is gathering wide spread attention with the major limitation to its application being its cost of operation and design considerations. While the general approach of most researches is to buttress the already known fact of the efficacy of the process, little attention is given to studying the by-products of ozone reactions with organics. The aims of this study were to investigate the efficacy of the ozonation process for removing recalcitrant phenolics: phenol, 2-chlorophenol (2CP), 4-chlorophenol (4CP) and 2,4-dichloropheno (2,4DCP) from aqueous medium with a view of understanding various reaction pathways of the process and identifying possible intermediates and residual compounds using liquid chromatography-mass spectrometry (LC-MS). The choice of the selected chlorophenols would also elucidate the role of the positioning of the chlorine atoms in determining reaction rates, pathways and subsequent mechanisms and by-products. Sequel to this, oxy-hydroxy iron in β-phase (β-FeOOH, akaganite) and various β-FeOOH bonded composites on support metal oxides (Al2O3, NiO and TiO2) were prepared via hetero-junction joining, and explored as a possible promoter to improve the efficiency of the ozonation process. Apparent first order reaction rates constants of tested phenolics was in the order 2,4-DCP > 2-CP > Phenol > 4-CP, irrespective of the tested pH. The individual rates however increased with increasing pH. The position 4 chlorine atom was found to be least susceptible to hydroxylative dechlorination. Catechol intermediate and pathway was identified as the major degradation pathway for phenol and 2-CP, while 4-chlorocatechol pathways were more important for 4-CP and 2,4-DCP. The formation of polymeric dimers and trimers by all compounds was pronounced at alkaline pH. Heterogeneous catalytic ozonation using β-FeOOH reduced ozonation time for 4-CP by 32%. Mechanism for β-FeOOH/ozone catalysis showed that the catalyst suffered reductive dissolution in acidic pH and the kinetics of 4-CP removal using the catalyst was best described using a two stage kinetic model. The first stage was attributed to heterogeneous catalysis of ozone breakdown on β-FeOOH surface generating faster reacting radicals, while the second stage was due to homogeneous catalysis by reduced Fe2+ ions in solution. β-FeOOH stabilized on NiO at a 5% ratio exhibited superior catalytic property compared to the other tested composites. Characterization by high-resolution transmission electron microscopy (HRTEM) affirmed a β-FeOOH-NiO bonded interfaced composite which was stable as a iv catalyst over four (4) recycle runs. The mechanism of operation of the composite was via an increased ozone breakdown to radicals as monitored via photoluminescence experiments. The composite material produced satisfactory results when tested on real wastewater samples. Results from this study contribute to the current understanding on reaction mechanisms for ozone with phenols and chlorophenols, for the first time monitoring time captured intermediates via liquid chromatography-mass spectrometric method, which preserves the integrity of reaction intermediates. Also this study proposes heterogeneous catalysts; β-FeOOH and β-FeOOH bonded composites as possible improvements for simple ozone based water purification systems.

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Notshe, Thandiwe Loretta. « Investigation of the bioconversion of constituents of olive effluents for the production of valuable chemical compounds ». Thesis, Rhodes University, 2002. http://hdl.handle.net/10962/d1007446.

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Olive mill wastewater is produced in large quantities during the production of olive oil and olive production effluents are produced during the processing of olives. This project was planned to find a use for constituents found in olive production wastewater. The task was carried out by first characterizing the olive effluents, then screening microorganisms for growth in the effluents and reduction of the pollutant properties of the effluents. An investigation into the biotransformation of aromatic compounds present in the effluents into useful chemicals, was carried out. The olive production effluents were collected from different stages in the process for treating olive wastewater, viz, a fermentation tank (FB), the surface of a digester (LV) and an evaporation pond (SO). The three effluents were characterized by investigating their phenolic composition. Protocatechuic acid, vanillic acid, syringic acid, hydroxyphenyl acetic acid, coumaric acid and ferulic acid were identified in an olive effluent, FB, using thin layer chromatography (TLC) and High perfomance liquid chromatography (HPLC). Hydroxyphenyl acetic acid constitutes almost 60% of the organics in olive effluent FB. Five bacteria, namely RU-LV1; RU-FBI and RU-FB2; RU-SOI and RU-S02, were isolated from the olive effluents LV, FB and SO respectively. These isolates were found to be halotolerant and were able to grow over a broad temperature and pH range, with the maximum temperature and pH for growth being 28°C and pH 7 respectively. A range of microorganisms were evaluated for their ability to grow and reduce the total phenolic content of the olive effluents. Among these Neurospora crassa showed the highest potential for the biological reduction of total phenolics in olive effluents. Approximately 70% of the total phenolic content was removed by N. crassa. Trametes verscilor, Pseudomonas putida strains, RU-KMI and RU-KM3s, and the bacteria isolated from olive effluents could also degrade the total phenolic content of olive effluents, but to a lesser extent. The ability of the five bacterial isolates to grow and degrade aromatic compounds was assessed by growing them in medium with standard aromatic compounds. RU-L V1 degraded 96%, 100%, 73% and 100% of caffeic acid, protocatechuic acid, p-coumaric acid and vanillic acid respectively. The other isolates degraded caffeic acid and protocatechuic acid, but their ability to degraded p-coumaric acid and vanillic acid was found to be lesser than the ability of RU-LV1 to degrade the same aromatic compounds. Whole cells of RU-LV1 degraded vanillic acid but no metabolic products were observed on HPLC analysis. Resting cells, French pressed extract, cell free extracts and cell debris from RU-LV1 cells induced with vanillic acid degraded vanillic acid, ferulic acid and vanillin at rates higher than those obtained from non-induced cultures. No products were observed during the degradation of vanillic acid. Ferulic acid was converted into vanillic acid by French pressed extract, cell free extract and cell debris of RU-LV1. The maximum yield of vanillic acid as a product (0 .23 mM, 50 %yield) was obtained when cell free extracts of RU-LVI, grown in glucose and induced by vanillic acid, were used for the degradation of 0.4 mM ferulic acid. Vanillin was rapidly converted into vanillic acid by resting cells, cell free extracts and French pressed extract of RU-LVI. Using molecular techniques, the similarity ranking of the RU-LVI 16S rRNA gene and its clone showed a high similarity to Corynebacterium glutamicum and Corynebacterium acedopltilum. The rapid degradation of vanillin to vanillic acid suggests that extracts from RU-LV1 degrade ferulic acid into vanillin which is immediately oxidized to vanillic acid. Vanillic acid is also considered as a high value chemical. This project has a potential of producing useful chemicals from cheap substrates that can be found in olive effluents.
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17

Nguyen, René-Viet 1981. « Catalytic tandem nucleophilic addition for the synthesis of heterocycles ». Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=115708.

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Classical methodologies for carbon-carbon bond formation often require stoichiometric amount of reagent to prefunctionalize a C-H bond. Such methods generate a lot of waste and are therefore not atom-efficient. On the other hand, the use of catalysts for the direct use of C-H bond without prior functionalization is a more desirable approach for carbon-carbon formation. For example, an overall addition reaction is 100% atom economical. This thesis focuses on the catalytic addition of the three types of C-H bonds (Csp-H, Csp2-H and Csp3-H) to unsaturated molecules such as conjugated dienes, imines and carbon dioxide to form heterocycles.
The first chapter describes the direct single addition of 1,3-diketones (Csp3- H bond) to conjugated dienes and enol ethers catalyzed by gold(III) chloride and silver(I) trifluoromethanesulfonate. The reaction is highly regioselective, although the overall yields are modest (up to 70%) due to the oxidative nature of the catalysts. Under certain conditions, the addition product undergoes a subsequent cyclization to form dihydrofurans. This tandem addition/cyclization reaction is catalyzed by trifluoromethanesulfonic acid and is discussed in the second part of the chapter.
The second chapter deals with the addition of phenol derivatives (C sp2-H bond) to conjugated dienes catalyzed by gold(III) chloride and silver(I) trifluoromethanesulfonate. The reaction affords dihydrobenzofurans via an intramolecular O-H cyclization. Investigation into the sequence of the reaction shows that the C-C bond is formed before the C-O bond.
The third chapter presents the addition of terminal alkynes (Csp-H bond) to imines catalyzed by cheap copper(I) iodide salt via a three-component coupling of salicylaldehyde derivatives, secondary amines and alkynes. Microwave irradiation is used which considerably shortens the reaction time and eliminate the use of solvents. Dihydrobenzofurans with an exocylic double bond are formed via an intramolecular O-H cyclization. The use of aliphatic alkynes molecules containing a heteroatom is critical to the success of the reaction.
Finally, in the last chapter, the addition of terminal alkynes (C sp-H bond) to carbon dioxide (catalyzed by gold(I) chlorotriphenylphosphine and silver trifluoromethanesulfonate) is applied to the synthesis of arynaphthalene lactones via a multicomponent coupling of phenylacetylene, CO2 and 3-bromo-1-phenyl-1-propyne.

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Ristic, Renata. « A study of seed development and phenolic compounds in seeds, skins and wines of Vitis vinifera L. cv. Shiraz / ». Title page, table of contents and summary only, 2004. http://web4.library.adelaide.edu.au/theses/09PH/09phr596.pdf.

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19

To, Tsz-kin James, et 杜子健. « Protective effects of some bioactive phenolic compounds against DNA adduct formation and interstrand cross-links caused by reactivecarbonyl species in chemical models ». Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2011. http://hub.hku.hk/bib/B46084551.

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20

Suvannachut, Kessara. « Scope and mechanism of the rearrangement of alkoxybenzyl anions to alkylphenoxide ions ; cyclophanes from 2,6-dimethylanisole ». Diss., The University of Arizona, 1989. http://hdl.handle.net/10150/184679.

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Alkoxy alkyl groups migrate to benzylic carbon when alkyl alkylphenyl ethers are treated with n-butyllithium and potassium t-butoxide. For alkyl 2,6-dialkylphenyl ethers, yields of the rearrangement products range from 45-70%. Rearrangement products are obtained in 10-30% yield from other dimethylanisoles and methylanisoles. The reactions appear to proceed by homolytic cleavage of the alkoxy alkyl group of alkoxybenzyl anions followed by recombination of the resulting radical pair in a different way. The reaction is useful for preparing 2,6-dialkylphenols and their corresponding ethers. The rearrangement can be avoided by using methyl ethers and working at or below room temperature. This was shown by reacting the dianion from methyl 2,6-dimathylanisole with dialkyl sulfates to give methyl 2,6-dialkylanisoles, with a,ω-dihalides to give methoxy[n]metacyclophanes (n = 8-15), dimethoxy[n.n]metacyclophanes (n = 5-10) and trimethoxy[S.S.S]metacyclophane, and with oxidizing agents to yield dimethoxy[2.2]metacyclophane.

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21

Lopez, Andres Patricia. « Bioavailability and antioxidant effect of dietary phenolic compounds in lamb tissues ». Doctoral thesis, Università di Catania, 2012. http://hdl.handle.net/10761/1128.

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Phenolic compounds are organic compounds distributed all over the plant kingdom and they are products of the secondary metabolism of plants. The main characteristic of phenolic compounds is to be antioxidant compounds. Phenolic compounds are present daily in human and animal diets. The study of bioavailability of phenolic compounds in monogastric has been widely studied but not in polygastric animals. The objective of the experiments carried out in the present thesis was to investigate whether different polyphenolic compounds or their metabolites could be detected in the tissues of lambs that had been fed previously with a specific diet. For the Experiment 1, lambs where fed with a diet supplemented with quebracho extract (characterised to be a rich source of profisetinidin compounds, a group of condensed tannins). In the other experiment (Experiment 2), lambs where fed on pasture, specifically with Lolium perenne (this plant belong to Poaceae family plant, which is not rich in polyphenolic compounds but contains some simple polyphenolic compounds). In both studies there was a control group, where lambs were fed with a commercial concentrate diet. In both experiments, no signals of the compounds present in feed samples or their corresponding metabolites were found in liver or plasma samples from lambs fed the respective diets. Furthermore, in both experiments the antioxidant status was measured in lamb tissue extracts that had either been treated or not treated with a Solid Phase Extraction (SPE) step. This step was used to purify samples and to isolate any phenolic compounds in the final extract. These experiments sought to investigate whether phenolic compounds have a direct or indirect antioxidant effect in lamb tissues. In both experiments it has been showed that phenolic compounds present in diets from Experiment 1 and Experiment 2 can improve the antioxidant capacity of tissues via an indirect effect. Further research is required to study the bioavailability of polyphenols compounds in ruminants and to understand the possible mechanism of action of polyphenolic compounds in improving the antioxidant status in ruminants.

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22

Kim, Do Hyong. « Formation of Aromatic Compounds by Cyclopentadiene Moieties in Combustion Processes ». Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/7241.

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Polycyclic aromatic hydrocarbon (PAH) formation and growth from cyclopentadiene (CPD) moieties have been investigated using a laminar flow reactor and molecular modeling. The resonance-stabilized cyclopentadienyl radical is readily formed in flames and can participate in PAH growth to soot by reaction with the ??onds of aromatic species. Both CPD pyrolysis and computational results indicate that formation of indene and benzene is favored at low temperatures (below 750oC) and formation of naphthalene is favored at high temperatures. Reaction pathways from CPD have further been extended to PAH formation from the reaction of CPD and aromatic compounds with different types of ??onds. Results indicate that, while the major products from the pyrolysis of CPD, acenaphthylene, styrene and phenanthrene mixtures are from the reaction of CPD to itself rather than to these aromatic compounds with different ??onds, CPD does add to these compounds to produce larger PAH. Polychlorinated naphthalene (PCN) formation from chlorinated phenols has also been studied. In combustion exhaust gas, chlorinated phenols can produce dioxin as well as PCNs. PCN and polychlorinated dibenzofuran (PCDF) congener product distributions were consistent with proposed pathways involving phenoxy radical coupling at unchlorinated ortho-carbon sites. Tautomerization of the phenoxy radical coupling and subsequent fusion via H2O loss results in PCDF formation. Competing with this reaction pathway, CO elimination and subsequent fusion via hydrogen and/or chlorine loss was found to produce PCNs. PCDF isomer distributions were found to be weakly dependent to temperature, whereas PCN isomer distributions were found to be more temperature sensitive with selectivity to particular isomers decreasing with increasing temperature. Results of this research contribute to a better understanding of chemical mechanisms involved in the formation of toxic byproducts and soot in combustion systems.

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23

Levén, Lotta. « Anaerobic digestion at mesophilic and thermophilic temperature : with emphasis on degradation of phenols and structures of microbial communities / ». Uppsala : Dept. of Microbiology, Swedish University of Agricultural Sciences, 2006. http://epsilon.slu.se/2006116.pdf.

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24

Mahmood, Banaz. « In vivo, in vitro micropropagation and chemical characterisation of medicinal compounds in chamomile and yarrow species (Asteraceae) ». Thesis, University of Plymouth, 2018. http://hdl.handle.net/10026.1/10662.

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The Asteraceae family is frequently used to describe several medicinal plants which contain various phytochemical compounds including phenols, flavonoids and terpenoids. Among the Asteraceae family German chamomile (Matricaria chamomilla L.) and yarrow (Achillea millefolium L.) plants are extant species used in contemporary medicine. These phytochemical compounds have been traditionally used since ancient times in health care systems worldwide as a source of medicines. The use of micropropagation is essential to improve and increase these active compounds via plant tissue culture within a short period of time using the application of key plant growth regulators (PGRs). Furthermore, quantitative and qualitative analysis using high performance liquid chromatography- ultraviolet detector (HPLC-UV) and gas chromatography- flame ionisation detector (GC-FID) of potential medicinal compounds expressed by both chamomile and yarrow are important points. The protocol of in vitro shoots, roots and callus formation of chamomile and yarrow seeds culture were investigated using Murashige and Skoog (MS) medium supplemented with different concentrations of plant growth regulators (PGRs). MS culture medium containing 0.5 mgL-1 IAA and 1.0 mgL-1 of GA3 were found to be the best culture medium for chamomile and yarrow seeds. In this project in vitro and in vivo growth rates of selected plant species were also investigated. In the earlier growth stages yarrow plants were found to grow much quicker than chamomile, while the yield of chamomile flowers was significantly (p ≤ 0.001) more than yarrow flowers. The phenolic, flavonoid and terpenoid compounds content of leaves and flowers of plants produced from both cultures were also studied. HPLC-UV analysis showed that chlorogenic acid, apigenin-7-O-glucoside and luteolin dominated as the main phenol and flavonoid compounds recovered in both in vitro and in vivo chamomile and yarrow cultures. However, GC-FID analysis indicated that farnesene and nerolidol were detected as the main terpenoid compounds present in the two culture conditions used to grow chamomile and yarrow plants. Moreover, this research examines how chamomile and yarrow plants can produce and improve their phytochemical compounds content not only under well-watered conditions but also under drought stress conditions. The main phenol and flavonoid compounds of chlorogenic acid, caffeic acid, apig-7-glucoside, umbelliferon and luteolin were found in chamomile and yarrow varieties grown under both well-watered and drought stress conditions using (HPLC-UV), however farnesene, nerolidol, chamazulene, α-(-)- bisabol and bisabolol oxide A were observed in the plant essential oils (EOs) using Soxhlet extraction and GC-FID analysis. The antibacterial activity of plant EOs was also investigated using disc diffusion and 96 well plates. In vivo chamomile EO showed the highest antibacterial activity against gram-positive and gram-negative bacteria strains. In addition, in vitro yarrow EO showed the greatest effect on the death of bacteria strains.

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Shewmaker, Patricia Lynn Wallace. « Enhanced biodegradation of phenolic compounds and cellular fatty acid analysis of bacteria using infrared pyrolysis/gas chromatography-mass spectrometry ». Diss., Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/25732.

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26

Deslauriers, Isabelle. « Recovery, separation and characterization of phenolic compounds and flavonoids from maple products ». Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0031/MQ64342.pdf.

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Côté, Jacinthe. « Separation and characterization of glycosylated phenolic compounds and flavonoids from maple products ». Thesis, McGill University, 2003. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=80242.

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Using a model system of glycosylated and aglycon standards consisting of rutin and quercetin respectively, and a series of pre-packed solid phase extraction cartridges, including C18 Extra-Clean, DSC-18, DPA-6S, Oasis HLB and Amberlite XAD-2. The experimental findings also showed that use of a commercial hesperinidase preparation, resulted in adequate hydrolysis of the glycosylated standard rutin. Based on these findings, the phenolic compounds and flavonoids from maple sap and syrup were separated using the Amberlite XAD-2 column, where the glycosylated fractions eluted with 60% aqueous methanol solution and the aglycon fractions eluted with a methanol:acetonitrile mixture (1:1, v/v). The recovered glycosylated fractions were subjected to enzymatic hydrolysis using the hesperinidase preparation and the liberated phenolic compounds and flavonoids, as well as the sugar components were analyzed by high-performance liquid chromatography (HPLC).

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28

Venter, Denise (Denise Louisette). « The separation of phenolic compounds from neutral oils and nitrogen bases ». Thesis, Stellenbosch : Stellenbosch University, 2001. http://hdl.handle.net/10019.1/52576.

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Dissertation (PhD(Eng))--University of Stellenbosch, 2001.
ENGLISH ABSTRACT: Coal pyrolysis liquors are a major source of phenolic compounds. The separation of the phenolic compounds from the neutral oils and nitrogen bases also present in the pyrolysis liquors is difficult due to low relative volatilities and the formation of azeotropes. The desired phenolic recovery and phenolic product purity of 99.5 % can therefore not be achieved by means of conventional separation processes. Alternative processes such as liquid-liquid extraction with various low-boiling solvents, mixtures of high-boiling solvents and extractive distillation have been investigated. Disadvantages of these processes include the high solvent ratios required, low recovery of the higher substituted phenolic compounds, inability to treat a wide-boiling feedstock in one process step and complex post-purification of the phenolic product. A solvent system consisting of a selective solvent, water as a co-solvent, and hexane as a countersolvent, is proposed. An industrial heavy naphtha stream was analysed and the most prevalent phenolic compounds, neutral oils and nitrogen bases identified. Three synthetic feed streams were compiled to represent the industrial stream, namely: 1. phenol + benzonitrile + aniline + mesitylene + 5-et-2-me-pyridine 2. m-cresol + o-tolunitrile + o-toluidine + pseudocumene + undecane + indene 3. 2,4-xylenol + 3,5-xylenol + 3,4-xylenol + indane + dodecane + naphthalene The stream containing phenol was used as a basis for solvent selection, with emphasis on the separation of phenol from benzonitrile. A variety of molecules containing hydroxyl and ether functional groups were identified as potential solvents by means of computer-aided molecular design using a genetic algorithm. Of the commercially available solvents tested on batch extraction scale, triethylene glycol achieved the highest phenol-benzonitrile, phenol-aniline and phenol-5-et-2-me-pyridine separation factors as well as the highest phenol recovery. It was concluded from the solvent selection process that effective solvents for the problem under investigation were those containing hydroxyl groups positioned on the molecule backbone in such a way as to facilitate hydrogen bonding with more than one phenolic molecule at a time. Two commercially unavailable solvents, 1,3-(ethoxy-2- hydroxy)-propane-2-01 and 1,3-(diethoxy-4-hydroxy)-propane-2-01 were therefore synthesised from ethylene glycol and diethylene glycol respectively. The molecular structures of these two solvents are analogous to that of triethylene glycol, and contain an additional hydroxyl group. The performance of the synthesised solvents was evaluated and compared to that of triethylene glycol on the basis of m-cresol-otolunitrile, 2,4-xylenol - o-tolunitrile, and 2,4-xylenol - o-toluidine separation factors and phenolic recoveries achieved by means of batch extraction tests. 1,3-(Diethoxy-4- hydroxy)-propane-2-01 yielded higher phenolic recoveries, but lower separation factors than did triethylene glycol. Triethylene glycol was therefore selected for further process development as it is commercially available. A series of batch extractions were carried out on each of the synthetic feed streams using the proposed solvent system. For phenol and m-cresol, recoveries in excess of 99% were obtained in a single stage. Recoveries in excess of 98% were obtained for the xylenol isomers. It was found that the recoveries of the xylenol isomers were more sensitive to changes in the solvent ratios. The separation of phenolic compounds from paraffins, naphthalene, indene, indane and the alkyl-substituted benzenes was trivial using the proposed solvent system. Highly satisfactory separation of the phenolic compounds from pyridines and aromatic nitriles was achieved. The separation of phenol from aniline, although satisfactory, was not as good. The optimum solvent to feed, water to solvent and hexane to feed ratios were identified as being 3.0, 5.0 and 0.25 respectively. Binary interaction parameters for the NRTL equation were obtained by regression of the equilibrium data from the batch extraction tests. The NRTL model fitted the equilibrium data satisfactorily. The proposed solvent system was tested on pilot plant scale. The performance of the extraction column was optimised using a synthetic feed stream consisting of m-cresol, p-cresol, aniline and o-tolunitrile. The optimum solvent ratios and operating parameters were then implemented in further tests on an industrial heavy naphtha stream. A phenolic product purity of 99.75% was achieved for this stream. The corresponding phenolic recovery was in excess of 91 %. The proposed separation process, including solvent recovery was simulated using the NRTL model with the experimentally determined interaction parameters. A single stream consisting of all the components used in the batch extraction tests was specified as the feed stream to the simulated process. A final simulated phenolic product purity of 99.5% and recovery in excess of 94% was obtained after solvent recovery. The optimum solvent to feed, hexane to feed and water to solvent ratios were determined as being 3.0, 5.0 and 0.25 in both the pilot plant tests and the simulated extraction process. It can be concluded that the proposed separation process is successful in recovering high purity phenolic compounds from tar liquors. Further development of the process has commenced in industry.
AFRIKAANSE OPSOMMING: Die pirolise van steenkool is 'n belangrike bron van fenoliese verbindings. Die skeiding van die fenoliese komponente vanuit die neutrale olies ook teenwoordig in die pirolise mengsel word bemoeilik deur lae relatiewe vlugtighede en die vorming van aseotrope. Dit is dus nie moontlik om die gewenste hoë fenoliese herwinning en fenoliese produk suiwerheid van 99.5% d.m.v. konvensionele distilleerprosesse te behaal nie. Alternatiewe prosesse soos ekstraktiewe distillasie en vloeistof-vloeistof ekstraksie met verskeie laagkokende oplosmiddels en mengsels van hoogkokende oplosmiddels is al ondersoek. Die hoë oplosmiddel verhoudings wat benodig word, lae herwinning van die hoërgesubstitueerde fenoliese verbindings, onvermoë om in een prosesstap 'n prosesstroom met In wye kookgebied te behandel en die ingewikkelde suiwering van die fenoliese produk tel onder die nadele van hierdie prosesse. 'n Oplosmiddelsisteem wat In selektiewe oplosmiddel, water as polêre oplosmiddel en heksaan as teenoplosmiddel bevat is as 'n alternatiewe proses voorgestel. 'n Industriële swaar nafta prosesstroom is ge-analiseer en die fenoliese verbindings, neutrale olies en stikstofbasisse met die hoogste konsentrasies daarin geïdentifiseer. Drie sintetiese strome is op grond van hierdie analise saamgestelom die industriële stroom te verteenwoordig: 1. fenol + benzonitriel + anilien + mesitileen + 5-et-2-me-piridien 2. m-kresol + o-tolunitriel +o-toluïdien + pseudokumeen + undekaan + indeen 3. 2,4-xilenol + 3,5-xilenol + 3,4-xilenol + indaan + dodekaan + naftaleen Die fenolbevattende stroom is as basis vir oplosmiddelkeuring gebruik, met die klem op die skeiding van fenol vanuit benzonitriel. Verskeie molekules wat hidroksie- en eter funksionele groepe bevat is as potensiële oplosmiddels uitgeken d.m.v. rekenaargesteunde molekulêre ontwerp met In genetiese algoritme. Hierdie oplosmiddels is d.m.v. enkellading ekstraksie toetse geëvalueer. Die kommersieel beskikbare oplosmiddel wat die hoogste fenol-benzonitriel, fenol-anilien en fenol-5-et-2-me-piridien skeidingsfaktore, sowel as die hoogste fenol herwinning op enkellading ekstraksie toetsvlak gelewer het, was triëtileenglikol. Vanuit die proses vir die keuse van 'n oplosmiddel was dit duidelik dat, vir hierdie skeidingsprobleem, die mees effektiewe oplosmiddels dié is met hidroksiel groepe wat so geposisioneer is in die oplosmiddel molekuul dat dit waterstofbindings kan vorm met meer as een fenoliese molekuul. Twee oplosmiddels wat nie kommersiëel beskikbaar is nie, 1,3-(etoksie-2-hidroksie)-propaan-2-01 en 1,3-(diëtoksie-4-hidroksie)-propaan-2- ol, is gesintetiseer vanuit etileenglikol en diëtileenglikol onderskeidelik. Die molekulêre strukture van hierdie twee oplosmiddels is analoog aan dié van triëtileenglikol en bevat 'n addisionele hidroksielgroep. Die effektiwiteit van die gesintetiseerde oplosmiddels is geëvalueer en met dié van triëtileenglikol vergelyk op grond van rn-kresol-o-tolunltriel, 2,4-xilenol - o-tolunitriel en 2,4-xilenol - o-toluïdien skeidingsfaktore en fenoliese herwinning behaal d.m.v. enkellading ekstraksie toetse. Hoër fenoliese herwinning en laer skeidingsfaktore is behaal met 1,3-(diëtoksie-4-hidroksie)-propaan-2-01as met triëtileenglikol. Triëtileenglikol is dus gekies vir verdere prosesontwikkeling aangesien dit kommersiëel beskikbaar is. Enkellading ekstraksie toetse is op elk van die sintetiese voerstrome uitgevoer met die voorgestelde oplosmiddelsisteem. Fenol- en m-kresol herwinning van meer as 99% en xilenol herwinning van meer as 98% is behaal. Die skeiding van fenoliese verbindings vanuit paraffiene, naftaleen, indeen, indaan en die alkielgesubstitueerde benseenverbindings is triviaal met die voorgestelde oplosmiddelsisteem. Hoogs aanvaarbare skeiding van fenoliese verbindings van die piridiene en aromatiese nitriele is vermag. Die skeiding van fenol en anilien is nie so goed nie, maar is nog steeds aanvaarbaar. Die optimum oplosmiddel tot voer, water tot oplosmiddel en heksaan tot voer is as 3.0, 5.0 en 0.25 vasgestel. Binêre interaksie parameters vir die NRTL vergelyking is verkry d.m.v. regressie van die ewewigsdata wat deur die enkelladingstoetse gegenereer is. Die NRTL model het die ewewigsdata goed gepas. Die voorgestelde oplosmiddelsisteem is op loodsaanlegvlak getoets. Die werking van die ekstraksie kolom is ge-optimeer met In sintetiese voerstroom wat uit m-kresol, pkresol, anilien en o-tolunitriel bestaan. Die optimum oplosmiddel verhoudings en bedryfstoestande is verder toegepas op 'n industriële swaar naftastroom. 'n Fenoliese suiwerheid van 99.75% is behaal met hierdie stroom. Die ooreenkomstige fenoliese herwinning was groter as 91%. Die voorgestelde skeidingsproses, insluitende oplosmiddelherwinning is gesimuleer met die NRTL model wat op die eksperimentele data gepas is. 'n Enkele stroom wat bestaan het uit al die komponente wat in die enkelladingstoetse gebruik is, is as die voerstroom tot die gesimuleerde proses gespesifiseer. 'n Finale gesimuleerde fenoliese produksuiwerheid van 99.5% en herwinning groter as 94% is na oplosmiddelherwinning behaal. Die optimum oplosmiddel tot voer, heksaan tot voer en water tot oplosmiddel verhoudings is vasgestel as 3.0, 5.0 en 0.25 onderskeidelik vir beide die gesimuleerde proses en die loodsaanleg toetse. Die voorgestelde skeidingsproses kan dus 'n hoogs suiwer fenoliese produk uit pirolisestrome herwin. Verdere ontwikkeling van die proses is in die industrie begin.

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Ghode, Amit Suresh. « Two-Phase Partitioning System Using Elvax 40W Polymer for the Biodegradation of Aqueous Phenols ». TopSCHOLAR®, 2010. http://digitalcommons.wku.edu/theses/224.

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A solid-liquid two phase partitioning system (TPPS) is a new technology platform for destroying toxic organic compounds. TPPS have traditionally been operated by using an immiscible organic phase which partitions organic compounds into the aqueous phase. TPPS using an immiscible organic phase suffers from several limitations such as the organic phase could be biodegradable and hence only certain compatible microbial strains could be used. This therefore, eliminates the desired use of mixed microbial populations for efficient degradation. A solid-liquid two phase partitioning system, in which solid polymeric beads replace liquid organic phase, appears to have benefits over the traditional liquid-liquid partitioning systems. The choice of suitable polymeric material should have similar absorption properties as the liquid organic solvent but have the added benefit of being able to be used with mixed microbial population. In this study, poly (ethylene-co-vinyl acetate), brand name ELVAX 40W, was selected as the test polymer in an effort to lower the concentrations of selected analytes; phenol, 4- nitrophenol and o-cresol in aqueous solutions. Studies were performed to determine the degree of partitioning using HPLC and UV-VIS. Kinetic studies were also performed and illustrated a first order dependence on the absorption of the phenols tested. Activation energies were also determined for each analyte. Rate constants were on the order of 10-4 min-1. Activation energy ranged from 19-46 kJ/mol. Regeneration tests showed that a release of analyte from the polymer is possible when the beads are placed in water. Therefore the ability to reuse the polymer is possible and therefore cost efficient. The polymer was observed to lower high concentrations up to 2000 ppm suggesting its potential use to treat the high concentrations of toxic organic compounds.

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Spencer, Paul Anthony. « Wound induced plant phenolic compounds and virulence gene expression in Agrobacterium species ». Thesis, University of British Columbia, 1991. http://hdl.handle.net/2429/31872.

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Crown gall disease of plants is caused by introduction of foreign DNA into susceptible plant cells by strains of Agrobacterium tumefaciens. The expression of bacterial virulence genes is triggered by chemicals present in plant wound exudates. The exudates contain a number of phenolic compounds which act as chemical signals inducing expression of a number of genes directing the DNA transfer process. These are the virulence or vir genes, and vir::lac reporter gene fusions have been widely used to assay vir gene induction in Agrobacterium tumefaciens strains. Using such strains to monitor vir gene expression, Stachel et al. (1985) isolated from Nicotiana tabacum two active acetophenones: 3,5-dimethoxy-4-hydroxyacetophenone, ("acetosyringone" or AS), and α-hydroxy-3,5-dimethoxy-4-hydroxy-acetophenone, ("hydroxyacetosyringone" or HO-AS). However, in vitro assay results suggested that other more common compounds also exhibited activity (Spencer and Towers, 1988). This analysis of structure-activity relationships of induced vir expression in A. tumefaciens was presented in a previous thesis (Paul Spencer, M.Sc. thesis). The results revealed that a variety of commonly occurring plant phenolic compounds were capable of activating vir genes. In addition to the acetophenones, a variety of benzoic and cinnamic acid derivatives, and even a few chalcones of appropriate ring substitution were active. This thesis reports the isolation and identification of a number of these compounds in plant wound exudates. Some Agrobacterium tumefaciens strains are restricted in host range to certain grapevine cultivars. Subsequent to the development of a convenient and sensitive plate-bioassay method, a strongly active component in grapevine wound exudates was purified. A newly described vir-inducing phenolic compound was isolated from a number of Vitis cultivars using gel filtration, thin layer and high pressure liquid chromatographies. This was identified as syringic acid methyl ester (3,5-dimethoxy-4-hydroxybenzoic acid, methyl ester), using mass spectrometry. However, the presence of this compound in grapevine wound exudates does not provide a simple explanation for host range limitation of grapevine strains since it induces vir gene expression in both limited and wide host range strains of A. tumefaciens. Interestingly, neither AS nor HO-AS were present in grapevine-derived extracts. A convenient polyamide column chromatographic method was subsequently developed to permit rapid purification of plant-derived vir gene inducing mixtures, which were detected using the newly developed plate bioassay. Derivatized polyamide fractions were then analysed by combined gas chromatography-mass spectrometry (GC-MS). GC-MS proved to be an ideal means for the identification of the phenolic components in partially purified extracts. Examination of wound exudates from a range of host and non-host species revealed that the production of the acetophenones is restricted to members of the Solanaceae. Some experiments focussed on the biosynthetic precursors of the acetophenones in Nicotiana species. Wound exudates of the majority of species belonging to other plant families contained benzaldehydes and/or benzoic and cinnamic acid derivatives. The induction of virE gene expression was examined in the related Agrobacterium species, A. rhizogenes. To do this, the virE::lacZ gene fusion plasmid pSM358cd was introduced into A. rhizogenes A4 by triparental mating and the strain "A4/pSM358cd" was used to analyze vir activation. Acetophenones, chalcones, benzaldehydes, and benzoic and cinnamic acid derivatives were found to activate vir genes in A. rhizogenes.
Science, Faculty of
Botany, Department of
Graduate

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Kirana, Chandra. « Bio-active compounds isolated from mistletoe (Scurulla oortiana (Korth.) Danser) parasitizing tea plant (Camellia sinensis L.) ». Title page, contents and summary only, 1996. http://web4.library.adelaide.edu.au/theses/09A/09ak58.pdf.

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Bibliography: leaves 87-96. This thesis investigates non-proteinaceous low molecular weight flavonoid and alkaloid compounds in Scurulla oortiana (Korth.) Danser grown on Camellia sinens. Three flavonols are identified in S. oortiana (Korth.) Danser growing on different hosts. The identification and characterisation of these flavonoids are carried out using various chromatographic and spectrometric procedures. Two purine alkaloids are isolated from and identified in S. oortiana (Korth.) Danser parasitizing tea plant, C. Sinensis. The antifungal activity of the phenolic compounds isolated from mistletoe parasitizing tea plant is examined.

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Jalalian, Nazli. « Development and Applications of Hypervalent Iodine Compounds : Powerful Arylation and Oxidation Reagents ». Doctoral thesis, Stockholms universitet, Institutionen för organisk kemi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-75810.

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The first part of this thesis describes the efficient synthesis of several hypervalent iodine(III) compounds. Electron-rich diaryliodonium salts have been synthesized in a one-pot procedure, employing mCPBA as the oxidant. Both symmetric and unsymmetric diaryliodonium tosylates can be isolated in high yields. An in situ anion exchange also enables the synthesis of previously unobtainable diaryliodonium triflates. A large-scale protocol for the synthesis of a derivative of Koser’s reagent, that is an isolable intermediate in the diaryliodonium tosylate synthesis, is furthermore described. The large-scale synthesis is performed in neat TFE, which can be recovered and recycled. This is very desirable from an environmental point of view. One of the few described syntheses of enantiopure diaryliodonium salts is discussed. Three different enantiopure diaryliodonium salts bearing electron-rich substituents are synthesized in moderate to high yields. The synthesis of these three salts shows the challenge in the preparation of electron-rich substituted unsymmetric salts. The second part of the thesis describes the application of both symmetric and unsymmetric diaryliodonium salts in organic synthesis. A metal-free efficient and fast method for the synthesis of diaryl ethers from diaryliodonium salts has been developed. The substrate scope is wide as both the phenol and the diaryliodonium salt can be varied. Products such as halogenated ethers, ortho-substituted ethers and bulky ethers, that are difficult to obtain with metal-catalyzed procedures, are readily prepared. The mild protocol allows arylation of racemization-prone a-amino acid derivatives without loss of enantiomeric excess. A chemoselectivity investigation was conducted, in which unsymmetric diaryliodonium salts were employed in the arylation of three different nucleophiles in order to understand the different factors that influence which aryl moiety that is transferred to the nucleophile.

At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Accepted. Paper 5: Submitted. Paper 6: Manuscript.

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Alessio, Rachael Josephine. « Removal of Bisphenol A Model Compounds and Related Substances Using Octolig® ». Scholar Commons, 2012. http://scholarcommons.usf.edu/etd/3946.

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Bisphenol A used in the production of polycarbonate plastics and epoxy resins is ubiquitous in the environment. The raw material is released to the environment during the manufacturing process and by leaching from consumer products. Recent studies are suggesting that low-dose amounts of Bisphenol A may have adverse health effects on humans. The possibility of removing Bisphenol A from natural water sources or from solvents used to extract the material from consumer products before they enter the market has been studied. The use of model compounds and related substances (4-isopropylphenol, 4-(t-butyl) phenol, and nitrophenols) have been used to study their removal from aqueous solutions using column chromatography and Octolig®, a commercially available material with polyethylenediamine moieties covalently bonded to high-surface area silica gel. The experimental results suggest that 2-nitrophenol and 4-nitrophenol can be successfully removed while 3-nitrophenol, 4-isopropylphenol, and 4-(t-butyl) phenol did not yield a high percent removal. A look at the pKa of the compounds provides an interesting explanation of the results. It is suggested that the compounds with a pKa of approximately 8.3 or higher would require the solution to be at a high pH for anion formation. The resulting pH of the solution would simultaneously deprotonate the ethylenediamine moieties of Octolig® rendering it incapable of removing the anions by ionic interaction.

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Zaffarano, Jennifer I. « Minimum inhibitory concentration of two common food phenolic compounds and their effects on the microbial ecology of swine feces in vitro ». Lexington, Ky. : [University of Kentucky Libraries], 2003. http://lib.uky.edu/ETD/ukyansc2003t00099/JZThesis.pdf.

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Thesis--University of Kentucky (M.S.), 2003.
Title from document title page. Document formatted into pages; contains ix, 127 p. : ill. Includes abstract and vita. Includes bibliographical references (p. 110-126).

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Warne, Michael St John. « Mechanism and Prediction of the Non-Specific Toxicity of Individual Compounds and Mixtures ». Thesis, Griffith University, 1991. http://hdl.handle.net/10072/365986.

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The toxicity of a range of hydrocarbons, phenols and pyridines were assessed. Such chemicals are classed as non-specific toxicants ie. they are neither an acid, base or a salt. Non-specific toxicants exert their toxicity by a mechanism termed narcosis. The toxicity of the test compounds to a mixed marine bacterial culture (containing thirteen different strains) was assessed both individually and in mixtures under static conditions. Thus, the reported toxicity values were actually the average toxicity of a compound or mixture to the thirteen different strains of bacteria. For homologous series of chemicals the toxicity tended to increase with increasing molecular weight until a point was reached beyond which a toxic effect could no longer by exerted. Evidence was presented that this cut off effect may not be due to aqueous solubility limiting accumulation of the toxicant but rather a volume based mechanism. The toxicity of structural isomers were different. These findings are suggestive of a more specific mechanism of action than narcosis. The toxicity of eighteen different mixtures of the test compounds were found to generally be synergistic. A currently accepted model for the toxicity of mixtures states that the toxicity of mixtures composed of toxicants with the same mechanism of action should be additive. Based on the observed mixture toxicity data and the above principle the test compounds exerted their toxicity by three different mechanisms of action. The compounds that exerted their toxicity in the same manner were: firstly polyaromatic hydrocarbons, 1-alkenes, alkyl-substituted benzenes and alkyl-substituted naphthalenes, secondly alkyl-substituted phenols and thirdly alkyl-substituted pyridines. The non-additive toxicity of mixtures composed of structural isomers indicates that structural isomers have different mechanisms of action; which is unusual considering the degree of chemical and structural similarity. High quality relationships were developed to predict the toxicity of individual compounds as well as other environmentally important properties ie. aqueous solubility and octanol-water partition coefficients. Relationships were developed using high performance liquid chromatography (HPLC) capacity factors. HPLC columns containing different stationary phases were combined in series, for the first time, and successful relationships with toxicity developed. This is a significant finding as it indicates there is the potential to specifically design stationary phases to reflect particular properties of the system being modelled. Relationships to describe the toxicity of mixtures were not of as high quality as those for individual compounds, but were satisfactory. A problem with such relationships is that it is difficult to infer a mechanism of action. The exact mechanism of action for non-specific toxicants remains unclear, despite being the subject of extensive research throughout this century. There are currently three major hypotheses for the mechanism of action; the critical concentration, critical volume and the protein binding hypotheses. Whichever, of the hypotheses is correct should be able to explain the toxicity of mixtures of non-specific toxicants as well as that for individual compounds. The ability of the critical concentration and volume hypotheses to describe the toxicity of individual compounds and mixtures was assessed by comparing literature data with predictions based on each of the hypotheses. The critical volume hypothesis, which states that toxicity occurs when the volume of target tissue increases to a certain volume due to the presence of a toxicant, was better able to describe the toxicity of non-specific toxicants. QSARs based upon parameters that measure the change in volume of a solution due to the presence of a solute (partial molar volume) were derived for the toxicity of individual compounds and mixtures. Both relationships lent further support to the critical volume hypothesis. A new hypothesis, called the funnel hypothesis, based upon the principles of the critical volume hypothesis and explaining the toxicity of mixtures in terms of partial molar volume was developed. This hypothesis is mechanistic and led to several predictions about the toxicity of equitoxic and non-equitoxic mixtures. Of these, the predictions for equitoxic mixtures were confirmed based upon comparison of the hypothesis' predictions and available literature toxicity data. Testing the validity of predictions for non-equitoxic mixtures was not possible due to the paucity of non-equitoxic mixture toxicity data. The predictions of the funnel hypothesis are: 1) the probability of a mixture, composed of non-specific toxicants with different mechanisms of action, deviating from toxic additivity will increase as the number of components decreases. The magnitude of the deviation is also likely to increase as the number of mixtures decreases. 2) the probability of a mixture, composed of non-specific toxicants with different mechanisms of action, deviating from toxic additivity will increase as the concentration of the components increases. The magnitude of the deviation is also likely to increase as the concentration increases.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Australian Environmental Studies
Science, Environment, Engineering and Technology
Full Text

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Khan, Wajahatullah. « Signal compounds involved with plant perception and response to microbes alter plant physiological activities and growth of crop plants ». Thesis, McGill University, 2003. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=82900.

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Recent preliminary data have suggested that microbe-to-plant signals, and plant internal signals elicited by microbial signals, affect aspects of plant physiology, development and growth. The reported research investigated the responses of plants to signal compounds of microbial and plant origin, such as lipo-chitooligosaccharides (LCOs - signal molecules in rhizobia-legume associations), chitin and chitosan (present in fungal cell walls), and phenolic compounds (salicylic acid, acetylsalicylic acid and gentisic acid - internal signals in plants, often affected by signals from microbes). Phenylalanine ammonia-lyase (PAL) and tyrosine ammonia-lyase (TAL) are key enzymes of the phenylpropanoid pathway. Oligomers of chitin and chitosan increased the activities of both PAL and TAL in soybean leaves. The degree of increase was dependent on oligomer chain length and time after treatment. LCO [Nod Bj V (C18:1 , MeFuc)] was isolated from Bradyrhizobium japonicum strain 532C. When Arabidopsis thaliana plants were grown for two weeks on agar containing this LCO (10-8M) or chitin pentamer (10-4 M), they had greater root length, root diameter, root surface area and number of root tips than control plants. Chitosan (tetramer and pentamer) did not have this effect. Chitin and chitosan were also tested for effects on corn and soybean photosynthetic rates and growth. High molecular weight chitosan generally reduced photosynthetic rates, but did not reduce the growth of corn or soybean. However, foliar application of 10-6 M LCO to corn leaves increased photosynthetic rates (up to 36%). Foliar application of lumichrome (10-5 and 10-6 M), a breakdown product of riboflavin produced by some rhizosphere bacteria, to corn (C4 plant) and soybean (C3 plant) increased photosynthetic rates (up to 6%). Foliar application of lumichrome (10-5 M) increased soybean leaf area and shoot dry weight. Foliar application of SA, acetyl salicylic acid (ASA) and gentisic acid (GT

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De, Villiers A. J. (Andre Joubert). « Evaluation of pressure- and electrodriven separation techniques for the determination of phenolic compounds in wine ». Thesis, Stellenbosch : Stellenbosch University, 2000. http://hdl.handle.net/10019.1/51753.

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Thesis (MSc)--Stellenbosch University, 2000.
ENGLISH ABSTRACT: The phenolic content of wine is responsible for determining characteristics such as the organoleptic qualities, colour stability, ageing properties and health-beneficial effects associated with wine. The aim ofthis study was to investigate the possibilities offered by capillary electrophoresis (CE) as an alternative separation technique to high performance liquid chromatography (HPLC) for the analysis of polyphenols in wine. The complexity of wine samples was the cause that neither technique was capable of a satisfactory singlestep analysis of wine. Suitable sample preparation techniques such as Sephadex- and Sep- Pak fractionation and ether extraction of wine polyphenols were investigated. These techniques did not, however, prove to be universal. A novel form of sample preparation namely a process analogous to lyophylization used to separate wine volatiles from nonvolatiles was introduced. The versatility of CE was further investigated in an attempt to eliminate the need for sample preparation. The use of polyvinylalcohol (PVA) coated capillaries, micellar electrokinetic chromatography (MEKC) and capillary gel electrophoresis (CGE) were investigated in this regard. Although none of these techniques could offer conclusive results, useful applications were forthcoming and routes for further investigation were outlined. Liquid chromatography coupled to electro spray ionisation mass spectroscopy (LC-ESI-MS) and capillary electrophoresis coupled to electro spray ionisation mass spectroscopy (CE-ESI-MS) were compared for the analysis of polyphenols in wine. While the latter technique could not produce sufficient separation compared to the former, future development ofCE-ESI-MS should make it a powerful technique for these analyses.
AFRIKAANSE OPSOMMING: Die fenoliese komponente in wyn speel 'n bepalende rol by eienskappe soos die organoleptiese karakter, kleur stabiliteit, verouderingspotensiaal en gesondheids-voordele wat met wyn geassosieër word. Die doel van hierdie projek was om ondersoek in te stel na die potensiaal wat kapillêre elektroforese (CE, "capillary electrophoresis") as 'n alternatiewe skeidingstegniek teenoor hoë druk vloeistof chromatografie (HDVC) vir die analise van die polifenole in wyn bied. Die kompleksiteit van wyn monsters is van so 'n aard dat 'n bevredigend enkelstap analise met geeneen van die tegnieke moontlik is nie. Gepaste monster-voorbereidingstappe soos Sephadex- en Sep-Pak fraksionering asook eter ekstraksie van die polifenole in wyn is ondersoek. Geeneen van die tegnieke was egter universeel toepaslik nie. 'n Nuwe metode van monster-voorbereiding, naamlik 'n proses analoog aan liofilisasie wat gebruik word om die wyn te skei in vlugtige en nievlugtige komponente is gedemonstreer. Die veelsydigheid van CE was gevolglik ondersoek in 'n poging om monstervoorbereiding uit te skakel. Die gebruik van polyvinielalkohol-(pVA) bedekte kapillêre, missellêre elektrokinetiese chromatografie (MEKC) en kapillêre gel elektroforese (CGE, "capillary gel electrophoresis) is in hierdie verband ondersoek. Alhoewel geeneen van hierdie tegnieke onweerlegbare resultate gelewer het nie, het bruikbare toepassings hieruit voortgespruit en is die grondslag vir verdere navorsing gelê. Vloeistof chromatografie gekoppel aan eIektrosproei ionisasie massaspektroskopie (LCESI- MS) en kapillêre elektroforese gekoppel aan elektrosproei ionisasie massaspektroskopie (CE-ESI-MS) is vergelyk vir die analise van polifenole in wyn. Alhoewel laasgenoemde tegniek onvoldoende skeiding lewer vergeleke met eersgenoemde, behoort toekomstige ontwikkelinge op die gebied van CE-ESI-MS dit 'n kragtige tegniek vir die analise van hierdie monsters te maak.

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Cardona, Claudia. « Investigation of the effect of structure on reactivity in the titanium dioxide mediated photodecomposition of phenols and haloethers when irradiated at 350 NM in an aqueous medium ». FIU Digital Commons, 1994. http://digitalcommons.fiu.edu/etd/2044.

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Three studies were performed to obtain fundamental mechanistic information on the TiO2 catalyzed photooxidations of organic substrates irradiated at 350 nm in dilute aqueous solutions under oxygenated conditions: (a) The photodecomposition of three haloethers, 2-chloroethyl ether, 4-chlorophenyl phenyl ether, and 4-bromophenyl phenyl ether, was investigated in an aqueous media at pH 7.0. (b) A comparative study of structure-reactivity was conducted on para-substituted phenols whose substituents range from electron-withdrawing to electron-donating in an aqueous media at pH 3.0. (c) The initial rates of the TiO2 catalyzed photodegratation of phenol were studied in an aqueous media at pH 1.0, 3.0, 5.0, 7.0, 9.0, 11.0, and 13.7 and a pH effect profile was obtained and compared to the removal efficiency after four hours of irradiation. Controls were carried out throughout the three studies in the absence of light and under anoxic conditions, as well as without the semiconductor to evaluate the role of photolysis. The Langmuir-Hinshelwood model was employed in an attempt to characterize and evaluate differences in reactivity.

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Harding, Alexander. « The prediction of mutagenicity and pKa for pharmaceutically relevant compounds using 'quantum chemical topology' descriptors ». Thesis, University of Manchester, 2011. https://www.research.manchester.ac.uk/portal/en/theses/the-prediction-of-mutagenicity-and-pka-for-pharmaceutically-relevant-compounds-using-quantum-chemical-topology-descriptors(40e87ff2-e161-4f4c-9e90-3a4e9087dc9e).html.

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Quantum Chemical Topology (QCT) descriptors, calculated from ab initio wave functions, have been utilised to model pKa and mutagenicity for data sets of pharmaceutically relevant compounds. The pKa of a compound is a pivotal property in both life science and chemistry since the propensity of a compound to donate or accept a proton is fundamental to understanding chemical and biological processes. The prediction of mutagenicity, specifically as determined by the Ames test, is important to aid medicinal chemists select compounds avoiding this potential pitfall in drug design. Carbocyclic and heterocyclic aromatic amines were chosen because this compounds class is synthetically very useful but also prone to positive outcomes in the battery of genotoxicity assays.The importance of pKa and genotoxic characteristics cannot be overestimated in drug design, where the multivariate optimisations of properties that influence the Absorption-Distribution-Metabolism-Excretion-Toxicity (ADMET) profiles now features very early on in the drug discovery process.Models were constructed using carboxylic acids in conjunction with the Quantum Topological Molecular Similarity (QTMS) method. The models produced Root Mean Square Error of Prediction (RMSEP) values of less than 0.5 pKa units and compared favourably to other pKa prediction methods. The ortho-substituted benzoic acids had the largest RMSEP which was significantly improved by splitting the compounds into high-correlation subsets. For these subsets, single-term equations containing one ab initio bond length were able to accurately predict pKa. The pKa prediction equations were extended to phenols and anilines.Quantitative Structure Activity Relationship (QSAR) models of acceptable quality were built based on literature data to predict the mutagenic potency (LogMP) of carbo- and heterocyclic aromatic amines using QTMS. However, these models failed to predict Ames test values for compounds screened at GSK. Contradictory internal and external data for several compounds motivated us to determine the fidelity of the Ames test for this compound class. The systematic investigation involved recrystallisation to purify compounds, analytical methods to measure the purity and finally comparative Ames testing. Unexpectedly, the Ames test results were very reproducible when 14 representative repurified molecules were tested as the freebase and the hydrochloride salt in two different solvents (water and DMSO). This work formed the basis for the analysis of Ames data at GSK and a systematic Ames testing programme for aromatic amines. So far, an unprecedentedly large list of 400 compounds has been made available to guide medicinal chemists. We constructed a model for the subset of 100 meta-/para-substituted anilines that could predict 70% of the Ames classifications. The experimental values of several of the model outliers appeared questionable after closer inspection and three of these have been retested so far. The retests lead to the reclassification of two of them and thereby to improved model accuracy of 78%. This demonstrates the power of the iterative process of model building, critical analysis of experimental data, retesting outliers and rebuilding the model.

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Carvalho, Paulo Sergio de 1966. « Ciclizações oxidativas de 3-hidróxi-benzenopropanóis promovidas por reagentes de iodo(III) hipervalente ». [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/250616.

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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

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Mohamed, Elham Farouk. « Removal of organic compounds from water by adsorption and photocatalytic oxidation ». Thesis, Toulouse, INPT, 2011. http://www.theses.fr/2011INPT0036/document.

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Les effluents industriels sont constitués de molécules de natures très diverses, plus ou moins réfractaires aux classiques traitements biologiques. Les normes de rejets évoluant régulièrement vers des contraintes de plus en plus sévères, il semble aujourd'hui nécessaire de proposer des solutions complémentaires pour atteindre de hauts rendements d'épuration. Le premier procédé mis en oeuvre dans ce travail est l'adsorption sur charbon actif. Le caractère novateur de cette technique se situe dans l'utilisation de charbons actifs fabriqués à partir de boues de stations d'épuration d'eaux usées. La seconde méthode est un procédé hybride innovant combinant adsorption et photocatalyse avec TiO2. Les eaux industrielles ciblées sont les effluents colorés, représentés par la tartrazine, et les effluents phénolés représentés par le phénol, l'acide p-hydroxybenzoïque, le p-chlorophénol er le p-nitrophénol. Pour traiter par adsorption les eaux chargées en phénols, plusieurs charbons actifs commerciaux et six charbons de boues ont été utilisés. Il ressort de cette première étude que, malgré leurs faibles surfaces spécifiques, certains charbons de boues présentent des performances très satisfaisantes. Le procédé séquentiel combinant adsorption et photocatalyse a été réalisé avec plusieurs matériaux: un tissu Ahlstrom contenant du charbon et du TiO2, un charbon actif avec dépôt de TiO2 par MOCVD puis un mélange de charbon actif et TiO2 en poudre. Des résultats prometteurs ont été obtenus pour dégrader la tartrazine, en particulier avec le TiO2 déposé sur charbon actif montrant que la proximité de sites d'adsorption et photocatalytique améliore les performances de l'oxydation
In order to explore a new sequential process for water treatment its two steps, adsorption on activated carbon and in situ photocatalytic oxidative regeneration, were investigated successively. Several commercial activated carbons (AC) and sewage sludge based activated carbons (SBAC) were tested with several phenols and one dye as pollutants. Despite low BET surface SBAC exhibits convenient adsorption properties. Photocatalysis on TiO2 was carried out with several materials to achieve activated carbon adsorption- egeneration process: a multilayer tissue with fixed granular AC and TiO2 on a sheet, a composite with TiO2, CVD deposited on AC, and AC-TiO2 powder mixture for comparison. Promising results were obtained especially with TiO2 deposited on AC proving the vicinity of adsorption and photocatalytic sites to be beneficial

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Espe, Austin Alexander. « Phenolic Bioactive-Linked Antioxidant, Anti-Hyperglycemic, and Anti-Hypertensive Properties of Serviceberry and Blackberry ». Thesis, North Dakota State University, 2019. https://hdl.handle.net/10365/29796.

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Production and consumption of edible berries are increasing rapidly in the United States, mostly due to their superior flavor profile, and popular diet-related value with their human health relevant bioactives and nutritional benefits. However, bioactive and nutritional qualities, especially human health protective phenolic antioxidants and associated non-communicable chronic disease (NCD) relevant health benefits of berries vary widely among accessions/cultivars and due to different production practices (organic vs conventional). Therefore, the aim of this thesis was to screen and select high phenolic and high antioxidant serviceberry and blackberry accessions/cultivars and to investigate the effect of different weed management and fertilization (organic vs. conventional) practices on phenolic bioactive linked antioxidant and anti-diabetic properties of blackberry using in vitro assay models. Overall, high phenolic-bioactive linked antioxidant and anti-hyperglycemic properties were observed in both serviceberry and blackberry accessions/cultivars and further for blackberry it was significantly higher under organic weed management and fertilization practices.

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Moura, Cristiane de. « Potencial antioxidante de extratos hidroalcoólicos de mirtilo, polpa de açaí e goji berry : efeito na estabilidade oxidativa e sensorial em queijo petit suisse ». Universidade Tecnológica Federal do Paraná, 2016. http://repositorio.utfpr.edu.br/jspui/handle/1/1760.

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CAPES
O interesse do consumidor por alimentos saudáveis, ricos em compostos antioxidantes é um dos fatores importantes para a redução de riscos de doenças e vem incentivando os pesquisadores e a indústria a desenvolver produtos e ingredientes inovadores e funcionais. Com esse intuito, o objetivo do trabalho foi determinar as melhores condições de extração de compostos bioativos presentes nas amostras polpa de açaí, mirtilo e goji berry utilizando a metodologia de superfície de resposta (RSM); avaliar a atividade antioxidante e antimicrobiana; identificar e quantificar os compostos por cromatografia líquida de alta eficiência (CLAE); avaliar a estabilidade oxidativa e sensorial do queijo petit suisse contendo os extratos liofilizados das amostras estudadas. Delineamento fatorial 2³ foi usado para analisar o efeito do solvente (etanol e água), tempo (30 e 60 min) e temperatura (30 °C e 60 °C) na extração e na determinação de compostos fenólicos totais (TCF) e atividade antioxidante (AA). As variáveis, tempo e temperatura apresentaram efeito positivo na AA em seus maiores níveis, 60 min e 60 ºC, respectivamente. O solvente etanol 80 % se mostrou mais eficiente na extração de TCF com AA em todas as matrizes. A identificação de compostos fenólicos realizada por CLAE revelou a presença de catequina, epicatequina, rutina, miricetina, ácido caféico, ácido ferrúlico e ácido cumárico. A polpa de açaí apresentou maior atividade antioxidante in vitro quando extraída a 60 °C por 60 min, porém nenhum dos três extratos analisados nestas condições apresentaram atividade antibacteriana contra as bactérias Staphylococcus aureus e Salmonella bongori nas concentrações testadas (95,00 a 2,34 mg/mL). A oxidação lipídica dos petit suisse foi inibida pela adição dos extratos liofilizados, revelando hjhgjggredução na produção de substâncias reativas ao ácido tiobarbitúrico e proporcionando a estabilidade da cor dos produtos durante o tempo de estocagem. O queijo petit suisse contendo extrato liofilizado de goji berry obteve maior aceitação sensorial entre os julgadores (75,67 %). Com estes resultados a substituição de antioxidantes e ingredientes sintéticos por extratos liofilizados pode ser uma alternativa para a elaboração de alimentos mais saudáveis e nutritivos, ricos em compostos fenólicos.
The consumer interest in healthy foods with high amounts of antioxidants is one of the important factors for reducing the risk of disease and it has encouraged researchers and industry to develop innovative and functional products and ingredients. To that end, the objective of this research was to study the bioactive compounds present in the acai pulp, blueberry and goji berry samples, as well as the phenolic compounds form of extraction using the response surface methodology (RSM), antioxidant and antimicrobial activity of it, identification and quantification of compounds by high-performance liquid chromatography (HPLC) and, at the end, the development of petit suisse cheeses added with freeze-dried extracts of the samples. A 2³ factorial design was used to analyze the solvent effect (ethanol and water), time (30 and 60 min) and temperature (30 °C and 60 °C) on the extraction and determination of total phenolic compounds (TPC) and antioxidant activity (AA). The variables time and temperature had a positive effect on the antioxidant activity (AA) in their highest levels with 60 min and 60 °C respectively. The ethanol solvent 80 % is more efficient in TPC extraction with AA in all arrays. The identification of phenolic compounds performed by HPLC revealed the presence of catechin, epicatechin, rutin, myricetin, chlorogenic acid, coumaric acid and ferulic acid. Regarding the AA the acai pulp showed higher activity in vitro when extracted by 60 °C for 60 min, but none of the three extracts analyzed under these conditions showed antibacterial activity against Staphylococcus aureus and Salmonella bongori in the concentrations tested (95.00 to 2.34 mg/mL. For petit suisse cheeses added with phenolic extract of the samples, the sample containing goji berry achieved greater sensory acceptance among judges (75.67%), second only to the commercial sample used for comparison with 91.56 % of acceptance. In relation to the storage time, the oxidation was evaluated by the level of thiobarbituric acid reactive substances and color analysis. Both analysis were satisfactory, making the extracts addition an alternative to preserve the product properties and give it a high content of bioactive and nutritive compounds.

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Cordeiro, Isabela Nogueira Fonseca. « Soluções antioxidantes e tratamento térmico na qualidade de batata-doce minimamente processada ». Universidade Estadual Paulista (UNESP), 2018. http://hdl.handle.net/11449/155888.

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Outra
A Batata-doce é um alimento versátil, de fácil aquisição e produção, entretanto, as raízes apresentam inconvenientes como desuniformidade, descasque e rápido escurecimento após o corte, por isso, esse vegetal mostra-se um produto com características a serem superadas pelo processamento mínimo. O uso de agentes antioxidantes e/ou tratamento térmico tem apresentado efeitos satisfatórios na qualidade pós-colheita de produtos hortícolas. Os ácidos cítrico e ascórbico atuam na inativação de enzimas responsáveis pelo escurecimento, devido à redução de pH e ação antioxidante, respectivamente. O tratamento térmico moderado que age na inativação de enzimas do escurecimento sem alterar a textura do vegetal. Nesse contexto, o objetivo desse estudo foi avaliar o efeito do ácido cítrico, ascórbico e tratamento térmico em diferentes concentrações e tempos na qualidade de batata-doce minimante processadas. As raízes de casca rosada e polpa amarela, foram, higienizadas, descascadas e feitos cortes transversais ao eixo principal obtendo rodelas de 1 cm de espessura, que foram submetidas a diferentes tratamentos, à saber, imersão em soluções de ácido citrico (AC) à 0, 1, 2 e 3% por 1 min; ácido ascórbico (AA) à 0, 1, 2 e 3% por 1min e tratamento térmico (TT) à 50°C por 0, 1, 3 e 5 min. Em seguida as batatas-doce foram centrifugadas e armazenadas em bandejas de tereftalado de polietileno (PET) a temperatura de 5 °C e 85% UR por um período de 8 dias. A cada 2 dias avaliou-se a perda acumulada de massa fresca, firmeza, índice de brancura, o pH, acidez titulável, sólidos solúveis, atividade respiratória. Amostras foram congeladas e armazenadas para análises posteriores de compostos fenólicos, atividade das enzimas peroxidase (POD), polifenoloxidase (PPO) e açucares solúveis. Batata-doce minimamente processada tratadas com 2% de ácido cítrico mostraram melhores resultados no escurecimento enzimático e qualidade do vegetal, enquanto o ácido ascórbico na concentração de 2%, apresentou melhor resultado na diminuição da atividade enzimática e qualidade do vegetal. O tratamento térmico a 50°C por 3 min, mostrou-se eficiente na qualidade de batata-doce minimamente processada.
Sweet potato is a versatile food, easy to acquire and produce, however, the roots present disadvantages such as unevenness, peeling and fast darkening after cutting, so this vegetable shows a product with characteristics to be overcome by the minimally processed. The use of antioxidants and / or heat treatment has shown satisfactory effects on the post-harvest quality of vegetables. The citric and ascorbic acids act in the inactivation of enzymes responsible for darkening, due to the reduction of pH and antioxidant action, respectively. The moderate heat treatment that acts in the inactivation of darkening enzymes without changing the texture of the vegetable. Therefore, this study aims to evaluate the effect of the acids citric and ascorbic combine with heat treatment at different concentrations and times in the quality of sweetened sweet potato processed. The roots with rosy peel and yellow pulp were cleaned, peeled and cut transversally around the principal axis, obtaining slices with 1 cm of thickness. The slices were submitted to different treatments, namely immersion in citric acid solutions (AC) at 0, 1, 2 and 3 % for 1 min; ascorbic acid (AA) at 0, 1, 2 and 3 % for 1min and, heat treatment (TT) at 50 °C for 0 (immersion in water at room temperature), 1, 3 and 5 min. Then, the pretreated sweet potatoes were centrifuged and stored in polyethylene terephthalate trays (pet) at 5°c and 85±5 % RH for a period of 8 days. Every 2 days the loss of accumulated fresh mass, firmness, whiteness index, pH titratable acidity, soluble solids and respiratory activity were evaluated. Samples were frozen and stored for further analysis of phenolic compounds, peroxidase enzyme activity (POD), polyphenoloxidase (PPO) and soluble sugars. The acid citric concentration of 2% provided the best whiteness index of the slices. Minimally processed sweet potato treated with 2% citric acid presented better results in enzymatic darkening and vegetable quality, while ascorbic acid at 2% concentration showed better results in the decrease of the enzymatic activity and the quality of the vegetable. The heat treatment at 50 °C for 3 min was efficient in the quality of the minimally processed sweet potato.

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Ribas, Maria Fernanda. « Avaliação do processo de obtenção de suco de uva gaseificado com elevado potencial antioxidante ». Universidade Tecnológica Federal do Paraná, 2018. http://repositorio.utfpr.edu.br/jspui/handle/1/3263.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
O setor de bebidas no Brasil tem passado por diversas transformações e está em franca expansão, acompanhando uma tendência mundial com maior demanda de produção de sucos prontos para o consumo em substituição aos refrigerantes. Isso se deve à busca do consumidor por produtos mais nutritivos e ainda, que forneçam algum efeito protetor para a saúde. O objetivo deste estudo foi desenvolver suco de uva gaseificado, a partir das cultivares BRS Violeta e Niágara Branca. Os sucos de uva foram desenvolvidos pelo método de arraste de vapor e carbonatados com dióxido de carbono. Os sucos foram caracterizados e avaliados durante o período de armazenamento refrigerado por 150 dias. Foram avaliados os seguintes parâmetros: composição centesimal, propriedades físico-químicas (pH, acidez titulável, sólidos solúveis, sólidos insolúveis, atividade de água), determinação de açúcares (glicose, frutose e sacarose), potencial antioxidante in vitro pelas metodologias ABTS, FRAP, DPPH e o teor de compostos fenólicos totais. As bebidas foram submetidas a avaliação sensorial por meio de teste de aceitação, utilizando escala hedônica de nove pontos e pesquisa de intenção de compra. A análise instrumental foi realizada pela detecção de gostos básicos (doce, salgado, ácido, amargo e umami) em língua eletrônica (e-tongue) e de compostos voláteis em nariz eletrônico (e-Nose). Como resultados, o rendimento dos sucos pelo processo de extração por arraste de vapor foi de aproximadamente 50% em ambas cultivares, e ainda apresentaram carbonatação adequada podendo receber a denominação “gaseificados”. O Suco de uva gaseificado BRS Violeta apresentou elevado potencial antioxidante, maior teor de glicose do que frutose, maior intensidade de gosto doce pelo padrão glicose. O Suco de uva gaseificado Niágara Branca mostrou maior teor de frutose do que glicose além de maior intensidade para o gosto doce pelo padrão frutose. A degradação dos compostos fenólicos foi evidenciada ao longo do armazenamento em ambos sucos, no entanto, a cultivar utilizada é um fator definitivo para obtenção de potencial antioxidante. Considerando a análise sensorial, o suco obtido da cultivar Niágara Branca apresentou maior aceitabilidade quanto aos atributos sensoriais avaliados e maior intenção de compra em comparação com o suco da cultivar BRS Violeta. No entanto, os sucos de ambas cultivares demonstraram potencial de mercado, decorrente do índice de aceitação acima de 80%. A análise sensorial por associação de palavras permitiu uma melhor percepção dos consumidores em relação aos termos “suco” e “néctar”. Pode-se concluir que a técnica de carbonatação do suco de uva por contrapressão foi eficiente, atingindo volume de gás adequado, levando ao desenvolvimento de uma bebida naturalmente saudável, a qual pode atender à demanda dos consumidores, com o atrativo diferencial de ser gaseificada.
Beverage industry in Brazil has been through several transformations and expansion and following the world trend with a greater demand of ready-to-drink juices instead of soft drinks. This is due to the consumer searches for more nutritious products and the provides protective effect on health. This work aimed to develop aerated grape juice, with the cultivars Vitis labrusca BRS Violeta and White Niagara. The juices were extracted using the vapor dragging method and carbonated with carbon dioxide. Juices were characterized and evaluated during refrigerated storage for 150 days. These parameters were evaluated: centesimal composition, physical-chemical proprieties (pH, titratable acidity, soluble solids, insoluble solids, water activity), sugars determination (glucose, fructose and sucrose), in vitro antioxidant activity using ABTS, FRAP and DPPH methodologies and determination of phenolic compounds content. The juices were submitted to sensory evaluation by means of acceptance test, using nine-point hedonic scale and purchase intention. The instrumental analysis was performed by detection of basic tastes (sweet, salty, acid, bitter and umami) in electronic tongue (e-Tongue) and the volatile compounds in electronic nose (e-Nose). As results, considering the vapor dragging method, the juices yield was 50% in both cultivars, and they still had adequate carbonation and could be called “carbonated”. The BRS Violeta aerated grape juice presented high antioxidant potential, higher glucose content than fructose, higher intensity of sweet taste by glucose standard. The Niagara Branca aerated grape juice presented higher fructose content than glucose, even higher intensity of sweet taste by fructose standard. Phenolic compounds degradation was evidenced through the storage in both juices, however, the cultivar used is a definitive factor to obtain antioxidant potential. Considering the sensory analysis, the Niagara Branca aerated grape juice presented greater acceptance regarding the sensorial attributes evaluated and the greater intention to buy it compared to cultivar BRS Violeta. However, the juices of both cultivars demonstrated market potential, due to the acceptance rate above 80%. Sensory analysis by words association technique allowed consumers a better perception regarding to the terms “juice” and “nectar”. As conclusion, the grape juice carbonation technique using back pressure was efficient, and reached adequate gas volume, therefore, let to the development of naturally healthy drink, which can meet the consumers demand, with the attractive differential of juice being carbonated.

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Khalaf, Eyada. « Phenolic-Linked Antioxidant and Anti-Hyperglycemic Properties of Selected Cereal, Pseudo-Cereal, and Millet Using In Vitro Screening Methods ». Thesis, North Dakota State University, 2018. https://hdl.handle.net/10365/29281.

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Improving diversity of food systems by targeting whole grain cereals, pseudo-cereals, and millets is essential to enhance nutritional qualities beyond macro and micronutrient balance and to address emerging global food and nutritional security-linked public health challenges. However, human health relevant nutritional parameters of whole grains vary widely among species, genotypes, growing conditions, and further due to different processing methods. Therefore, it is important to screen human health relevant nutritional parameters of these whole grains prior to targeting them for wider public health solutions linked to non-communicable chronic diseases (NCD). Based on this rationale, oats from different processing stages and from different production systems, buckwheat, teff, pearl millet, and different genotypes of sorghum were analyzed for health relevant phenolic bioactive linked antioxidant and anti-hyperglycemic properties using in vitro assay models. Overall, high phenolic-linked antioxidant and anti-diabetic properties were observed in whole grain oats, rolled oat, buckwheat, teff, and select sorghum genotypes.

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Soucek, Richard. « Synthesis of new heteropolycyclic compounds with potential antitumor activity = Preparació de nous compostos fenólics i derivats amb potencial activitat antitumoral ». Doctoral thesis, Universitat de Barcelona, 2014. http://hdl.handle.net/10803/133830.

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The study deals with the synthesis and biological activity of 4 different antitumours: Tetrahydro-[1,4]-dioxanisoquinolines, combretastatin A-4, dioxancarbazoles and resveratrol analogues. This study describes the synthesis strategy and multi-step synthesis of these potential antitumour compounds. Various tetrahydroisoquinolines were synthesized, five of which were biologically tested and have a promising K-Ras inhibition activity. Two of them show a high antiangiogenesis activity, one of which also presents antiosteoporosis properties. Two pirazolone derivatives were synthetized and biologically tested, one of which shows a very high K-Ras inhibition, antiangiogenesis and antiosteoporosis activity and inhibits the G2 cell cycle phases and subphases. Two azoledione combretastatin A-4 derivatives were also synthesized and will be biologically tested. Two dioxancarbazoles were prepared and biologically tested, one of which shows a high K-Ras and angiogenesis inhibition. Finally, four resveratrol analogues were synthesized and biologically tested. Their biological results show a moderate and selective K-Ras inhibition on the studied cell lines. In the future, the rest of the synthesized compounds are to be biologically tested. Further CDKs and topoisomerase II inhibition trials as well as toxicity studies will be carried out.
El estudio trata de la síntesis y la actividad biológica de 4 antitumorales diferentes: Análogos de tetrahidro-[1,4]-dioxanisoquinolinas, de combretastatina A-4, de dioxancarbazol y del resveratrol. El estudio describe la estrategia sintética y la síntesis multietapas de esos compuestos potencialmente antitumorales. Varias tetrahidroisoquinolinas fueron sintetizadas, cinco de ellas fueron probadas biológicamente y presentan una actividad de inhibición de la proteína K-Ras prometedora. Dos de esos compuestos presentan una actividad anti antiangiogénica elevada y uno presenta actividades de antiosteoporosis. Dos derivados de pirazolona fueron sintetizados y probados biológicamente, uno de ellos muestra una inhibición muy elevada de la K-Ras, de antiangiogénesis y de antiosteoporosis e inhibe la fase G2 del ciclo celular y sus subfases. Se han preparado dos derivados de azolediona combretastatina A-4 que se evaluarán biológicamente. Se sintetizaron dos derivados de dioxancarbazol, uno de ellos presenta una actividad alta de la K-Ras y de antiangiogénesis. Finalmente, se prepararon y evaluaron biológicamente cuatros análogos del resveratrol. Los resultados biológicos muestran una inhibición moderada y selectiva de la K-ras en las líneas celulares estudiadas. Próximamente, el resto de los compuestos sintetizados se evaluarán biológicamente. Ensayos adicionales de inhibición de CDKs, de topoisomerasa II y de toxicidad serán llevados a cabo.

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Erturk, Bedriye Durhan. « Determination Of Phenolics Concentration Using Cross-linked Phenol Oxidase Aggregates ». Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12609647/index.pdf.

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The main object of the presented study was investigation of the use of cross-linked enzyme (tyrosinase) aggregates (CLTA) obtained from crude mushroom extract for a rapid phenolic content analysis in wines. In addition, a comparison of phenolic characteristics of Turkish red wines was performed. Reproducible and reliable results in total phenolic measurement were obtained with CLTAs similar to pure tyrosinase and tyrosinase obtained from crude mushroom extract. Measurement of total phenolic content is possible both in standard solutions and in complex matrices, such as wine. In a very short time period, 10 seconds, phenolics content in red and white wines produced from grapes of Turkey were investigated by using CLTAs. Results were consistent when compared to a well known phenolic measurement method, Folin-Ciocalteau. CLTAs exhibited very high operational stability and retained more than 90% of its activity after 30th use. Moreover, it showed good shelf-life stability for about 2 months storage by maintaining 90% of its maximum activity. So, use of CLTAs prepared from crude mushroom extract is an effective, fast and cheap alternative in total phenolics measurements in wines. Moreover, a novel catalase phenoloxidase (CATPO) produced by a fungal microorganism, Scytalidium thermophilum, was studied to check its capabilities in phenolics measurements. This novel catalase phenol oxidase showed similarly good results, exhibiting widesubstrate selectivity.

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Scheffler, Thomas, Sascha Englich et Michael Gehde. « Specific mold filling characteristics of highly filled phenolic injection molding compounds ». Universitätsbibliothek Chemnitz, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-198644.

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Thermosets show excellent mechanical properties and chemical resistance (for most automotive fluids) even at high temperatures up to 300 °C. Furthermore they can be highly efficient processed by injection molding. So they should be particularly suited for e.g. under the bonnet applications. However, the reality shows that thermosets are, except fiber reinforced composites, heavily underrepresented in technical applications. E.g. thermosetting components only account 0,2 % to a vehicle’s weight. Therefore reasons can be found in limited knowledge, e.g. relating mold filling behavior. The objective of the study is to analyze the influence of the mold filling behavior during injection molding of highly filled phenolic compounds on mechanical properties. Injection molding filling studies, mechanical testing and optical microscopy were done while varying mold geometry (injection gate and cavity height), mold temperature and injection rate during injection molding a highly filled phenolic compound. It was found that the mold filling behavior varies with altered injection molding parameters as well as the mold geometry. In consequence of this the mechanical properties change according to the resulting reinforcement orientation. The results can help to improve part and mold design for optimal load transmission.

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ADAME, GISELE. « Desenvolvimento e validação de método para a extração e quantificação de compostos fenólicos em sedimento. Estudo de caso : Reservatório Guarapiranga, SP ». reponame:Repositório Institucional do IPEN, 2016. http://repositorio.ipen.br:8080/xmlui/handle/123456789/26931.

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Compostos fenólicos vêm despertando preocupação nos últimos anos e incitando grande atenção em todo o mundo ao desenvolvimento de métodos de determinação e monitoramento contínuo no ambiente devido a sua elevada toxicidade e persistência no meio ambiente, principalmente no sedimento, que devido sua característica em acumular compostos faz desse um dos compartimentos mais importantes na avaliação do nível de contaminação de ecossistemas aquáticos continentais. Neste estudo foi desenvolvido um método analítico utilizando cromatografia a gás acoplada ao detector de espectrometria de massas (GC/MS) para a determinação de seis compostos fenólicos e foi avaliada a presença dos mesmos em amostras de sedimento do Reservatório Guarapiranga, um reservatório de usos múltiplos da água, destinado principalmente para abastecimento público de água potável da Região Metropolitana de São Paulo. Para garantir a reprodutibilidade do método de forma confiável atendendo aos objetivos e qualidade propostos, a metodologia desenvolvida foi submetida ao processo de validação, em que os parâmetros seletividade, linearidade, faixa de trabalho, limite de detecção, limite de quantificação, tendência/recuperação, precisão (repetitividade, precisão intermediária e reprodutibilidade) e robustez foram avaliados. A metodologia aqui proposta mostrou ser adequada para alcançar o objetivo de avaliar os compostos em estudo, e pela sua aplicação foi constatada a presença dos compostos fenol e 3-metilfenol no sedimento do reservatório. Nas amostras de sedimento coletadas em 2011, o fenol foi o composto encontrado com maior frequência, com alguns resultados acima do LQ, principalmente em pontos com maior influência urbana, em concentrações de 0,09 a 0,19 μg g-1. Também foi encontrado o 3-metilfenol com resultados acima do LQ em dois pontos de coleta, G-11 e G-13, nas concentrações de 0,10 e 0,19 μg g-1 respectivamente. Já na coleta realizada em outubro de 2014, o composto 3-metilfenol foi quantificado em dois pontos de coleta, G-02 e G-07, nas concentrações de 0,07 e 0,08 μg g-1 respectivamente, sendo detectado abaixo do LQ em diversos pontos ao longo do reservatório. A presença destes compostos mesmo em baixas concentrações pode indicar uma contaminação decorrente de atividades industriais nas margens do reservatório e considerando-se que os compostos em sedimento com o tempo podem ser liberados na coluna dágua e causar contaminação na água de abastecimento este estudo fornece subsídios para revisão da legislação vigente que não estabelece limites para os compostos fenólicos na matriz de estudo.
Dissertação (Mestrado em Tecnologia Nuclear)
IPEN/D
Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP

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