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. (1969): Phenolic substances in grapes and wine and their significance . Academic Press, New York, London, pp. 8–14. Esau P. Phenolic substances in grapes

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Abstract  

The properties of polymeric blends originate from the synergistic association of their components. In this investigation, phenolic resins obtained by the reaction of cashew-nut shell liquid (CNSL) and aldehyde are used in several applications. Mixtures of CNSL with industrial reject ethylene-co-vinyl acetate (EVA reject) were prepared with an EVA reject content up to 70%. The thermal compatibility and stability were evaluated by means of thermogravimetry (TG), derivative thermogravimetry (DTG) and differential scanning calorimetry (DSC). For blends containing a high percentage of EVA reject, the TG curves clearly show two decomposition stages, one at 350‡C and the other at 450‡C (onset 467‡C). The DIG curves of the blend containing 70% CNSL exhibit decomposition at 240‡C. The DSC curves show that the samples containing a high percentage of EVA reject are incompatible, withT g values around −30‡C.

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of Cu(II) complex with Schiff base of [2-(1,2,3,4-thiatriazole-5-yliminomethyl)-phenol] and calculation of kinetic parameters, i.e., order of reaction, activation energy, entropy of activation, and frequency factor using Freeman and Carroll as well as

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88 359 365 Zieslin, N. and Ben-Zaken, R. (1993): Peroxidase activity and presence of phenolic substances in peduncles of rose flowers. Plant Physiol

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anatomical–functional damage to our bodies detected with ageing. Ingredients that contain a phenolic group play a significant role in cosmetics, pharmaceutical products and food, to delay and inhibit cell ageing. Various techniques of analysis have been made

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Phenolic compounds, such as flavonoids and phenolic acids, are very important substances that occur in various medicinal plants. They show different pharmacological activities which might be useful in the therapy of many diseases. Phenolic compounds have achieved an increasing interest over the last years because these compounds are easily oxidized and, thus, act as strong antioxidants. We present the chemiluminescence of different phenolic compounds measured directly on high-performance thin-layer chromatography LiChrospher® plates using the oxalic acid derivative bis(2,4,6-trichlorophenyl) oxalate (TCPO) in conjunction with H2O2. Our results indicate that chemiluminescence intensity increases with an ascending number of phenolic groups in the molecule. The method can be used to detect phenolic compounds in beverages like coffee, tea, and wine.

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Abstract  

In this study, the sorption behavior of two important contaminants, phenol and radioactive cesium (137Cs), onto surfactant modified insolubilized humic acid (SMIA) were investigated as a function of time, sorbate concentration utilizing the radiotracer method and UV–Vis spectroscopy. Phenol sorption process was well described by both Freundlich and Tempkin type isotherms, and cesium sorption was described by Freundlich and Dubinin–Radushkevich isotherms. It was found that SMIA adsorbs both cations and phenolic substances. Kinetic studies indicated that adsorption behavior of phenol obey the pseudo second order rate law. FTIR spectroscopic technique was used to understand the structural changes during modification process with surfactants.

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Summary  

The effect of irradiation using several doses of X- and γ-rays (10, 20, 40, 60, 80 and 100 kGy), upon total phenolic compounds contained in the leaves of Maytenus aquifolium Martius (Celastraceae) "espinheira santa", was investigated. The content of phenolic compounds (measured by the Folin-Denis spectrophotometric method) was unaffected by X- or γ-ray irradiation, at any dose.

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Abstract  

Phenol is industrially produced by the Hock process, in which cumene hydroperoxide (CHP) is decomposed with sulfuric acid to obtain equimolar amounts of phenol and acetone. Use of the liquid acid requires subsequent neutralization and purification of the phenol at substantial cost, and a waste stream generation that could be avoided if an effective solid acid catalyst could be used. Modified clays exhibit attractive properties as solid acids. Acid treatment produces an increase in surface area and acidity. The present study was undertaken to modify bentonite clay by treatment with hydrochloric acid for the production of phenol and acetone via the decomposition of cumene hydroperoxide. The effects of various parameters such as acid activation, catalyst weight, concentration of CHP, reaction temperature and reusability of catalyst were studied. The results indicate that the acid-modified bentonite catalyst may be used instead of sulfuric acid for selective decomposition of CHP into phenol and acetone.

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Emodin and twelve phenolic acids (ellagic, gallic, protocatechuic, homoprotocatechuic, caffeic, p -hydroxybenzoic, p -coumaric, syringic, vanillic, ferulic, α-resorcylic, and p -hydroxyphenylacetic) have been detected in the petioles of Rheum rhaponticum L. ( R. rhabarbarum L.) and Rheum undulatum L. by TLC. The amounts of emodin (4 μg g −1 for R. undulatum , 5.8 μg g −1 for R. rhaponticum ) were determined by TLC-densitometry. The amounts of the nine phenolic acids were determined by HPLC. The total amount of phenolic acids in the petioles was 327.4 μg g −1 for R. undulatum and 198.16 μg g −1 for R. rhaponticum .

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