Results 261 to 270 of about 94,108 (310)
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Regioselective Monobromination of Free and Protected Phenols
European Journal of Organic Chemistry, 2007AbstractA comparative study of the advantages of using THF compared with DMF in regioselective monobromination reactions of highly activated polyphenols, their ethers, and their tert‐butyl carbonate derivatives under mild conditions is described. Bromination with the common reagent N‐bromosuccinimide in polar solvents provided an easy and fast approach
Daniel Pla +2 more
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On the determination of free phenol in phenol‐formaldehyde resins
Recueil des Travaux Chimiques des Pays-Bas, 1958AbstractThe time necessary for the determination of free phenol in phenol‐formaldehyde resins and moulding powders can be appreciably reduced by the addition of glycol to the resin during the steam distillation.
R. Dijkstra, M. F. Lammers
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Cation–anion CH⋯O− interactions in the metal-free phenolate, tetra-n-butylammonium phenol-phenolate
Tetrahedron, 2002Abstract Deprotonation of phenol by tetra-n-butylammonium hydroxide and subsequent removal of water by P2O5 results in quantitative formation of tetra-n-butylammonium phenol-phenolate. The compound crystallizes as an ion pair, with the solute phenol molecule intimately attached to the phenolate anion by an O–H⋯O− hydrogen bond (O⋯O 2.471(5) A).
Richard Goddard +2 more
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Hydroxyl free radical reactivity toward aqueous chlorinated phenols
Water Research, 2005Second-order kinetic constants (k(OH,S)) for the hydroxyl free radical attack on a series of nine chlorophenols (2-chlorophenol, 2,4-dichlorophenol, 2,5-dichlorophenol, 2,4,5-trichlorophenol, 2,4,6-trichlorophenol, 2,3,5,6-tetrachlorophenol, 2,3,4,5-tetrachlorophenol, 2,3,4,6-tetrachlorophenol, and pentachlorophenol) in aqueous solution were determined
Julio A, Zimbron, Kenneth F, Reardon
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Evaluation of the Phenol-Free Glycosyl-Glucose Determination
American Journal of Enology and Viticulture, 2000Published ...
Zoecklein, Bruce W. +2 more
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Reducing the contents of free phenol and formaldehyde in phenolic foam
Journal of Applied Polymer Science, 2003AbstractThe problem of overly high contents of remnant monomers (free phenol and free formaldehyde) in phenolic foam was studied. Free phenol was characterized by iodimetry, and free formaldehyde was characterized by a hydroxylamine hydrochloride method.
Li, WL, Lin, Q, Yan, MF, Zou, YS
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Food Chemistry, 2021
The free, esterified and bound forms of 37 phenolic compounds (including hydroxybenzoic acid, hydroxycinnamic acids, flavanols, flavonols and flavones) from walnut kernel (Juglans regia L.) were investigated in this study. Results showed that the majority of walnut phenolics were presented in the free form (51.1%-68.1%), followed by bound (21.0%-38.0%)
Shutian, Wu +7 more
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The free, esterified and bound forms of 37 phenolic compounds (including hydroxybenzoic acid, hydroxycinnamic acids, flavanols, flavonols and flavones) from walnut kernel (Juglans regia L.) were investigated in this study. Results showed that the majority of walnut phenolics were presented in the free form (51.1%-68.1%), followed by bound (21.0%-38.0%)
Shutian, Wu +7 more
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Free radical oxidation of dihydric phenols with diphenylpicrylhydrazyl
Talanta, 1967A spectrophotometric study has been made of the reactions between the free radical 2,2-dipheny1-1-picrylhydrazyl (DPPH) and the three dihydric phenols. It has been shown that water affects the rate of all three reactions and the stoichiometry of the DPPH-catechol (pyrocatechol) reaction.
G H, Schenk, D J, Brown
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DETERMINATION OF FREE PHENOL IN PHENOL RESOLE RESIN BY GEL PERMEATION CHROMATOGRAPHY
Chemistry Letters, 1973Abstract The free phenol in phenol resole resin was determined by gel permeation chromatography with the high molecular polystyrene as the internal standard. The observed values were in close agreement with that obtained by gas chromatography. The reproducibility was about 4 per cent as the coefficient of variance.
Morio Tsuge +2 more
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Phenol biodegradation by free and immobilized Acinetobacter
Biotechnology Letters, 2002Acinetobacter sp. strain W-17, immobilized on porous sintered glass completely degraded 500 mg phenol l−1 in 40 h, but free cells required 120 h for this to be achieved. Immobilized cells can be used 7 times without losing their activity.
Usama Beshay +3 more
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