Phenol, m-

A hydroxyl group is a very powerful activating substituent and electrophilic aro matic substitution m phenols occurs far faster and under milder conditions than m ben zene The hrst entry m Table 24 4 for example shows the monobrommation of phenol m high yield at low temperature and m the absence of any catalyst In this case the reac tion was carried out m the nonpolar solvent 1 2 dichloroethane In polar solvents such as water it is difficult to limit the brommation of phenols to monosubstitution In the fol lowing example all three positions that are ortho or para to the hydroxyl undergo rapid substitution... 

Mass Spectrometry A peak for the molecular ion is usually quite prominent m the mass spectra of phenols It is for example the most intense peak m phenol... 

The hydroxyl group of a phenol is a strongly activating substituent and electrophilic aromatic substitution occurs readily m phenol and its deriv atives Typical examples were presented m Table 24 4... 

M SiCl4, 3 M phenol, CH2CI2, 10 min. The Fmoc, Cbz, and Bn ester and ether groups were not noticeably cleaved even after 18 h of exposure." ... 

Phenolat, n. phenoxide, phenolate. Phenol-ather, m. phenol ether, -carbonsaure, /. phenolcarboxylic acid, -gruppe, /, phenol group,... 

M phenol(aq), ignoring the effect of the autoprotolysis of water, (b) Repeat the calculations, taking into account the autoprotolysis of water. 

FIGURE 6. Voltammetric curves in DMF-TBAP 0.1 m, stationary mercury microelectrode, sweep rate lOmVs" (1) without phenol, (2)10 m phenol added (a) PhSOjCHjPh, (b) PhSOjC(Et)(Me)Ph. 

Faulkner (1923 1927) reported that mutarotation occurred much more readily in a mixture of pyridine and cresol than in either by itself. Swain and Brown (1952) extended this work and found that a-pyridone, where an acidic and a basic group are incorporated in the same molecule, is an excellent catalyst, 0 05 M concentration giving rise to a reaction 50 times faster in benzene solution than a solution of 0 05 M phenol and 0-05 M pyridine. A 0-001 M solution of a-pyridone was 7000 times more effective than equivalent concentrations of phenol and pyridine. A concerted mechanism was proposed [4]. 

Phenolic acids have already been discussed as inhibitory compounds. But inhibition of germination requires a concentration of 10 to 10 M phenolic acids. (j ). Such high concentration may locally be achieved if oat straw is accumulated in the fields (4). This could sometimes be a reason for poor plant growth on fields after harvest of oats without removal of straw. We did not find such concentrations in our husk extracts, however they were 100 - 1000 fold smaller than expected from bioactivity. Phenolic acids are therefore not the active compounds in our inhibitory extracts. 

Phenol-grown cells nearly quantitatively bind and carry down phenol and some of the cresols in concentrations 8 x 10-3 mg/ml (ca. 6 x 10-5 M). Phenol and o-, p-, and m-cresol are stripped as shown in Figure 5a. In contrast, little vanillic acid is removed by phenol-grown P. putida,... 

Sodium phenate solution - dissolve 259 g of sodium hydroxide in approximately 1 I of water and allow to cool. Add 315 ml of 80% m/m phenol solution (Fisher) slowly with stirring. Cool and make up to 2 I store in a refrigerator. 

Souquet, J.-M., Cheynier, V., and Moutounet, M., Phenolic composition of grape stems. In XIX ernes journees internationales deludes des polyphenols (eds F. Charbonnier, J.M. Delacotte and C. Ronaldo), France, 1998. 

Ferroni, F., Maccaglia, A., Pietraforte, D., Turco, L., and Minetti, M., Phenolic antioxidants and the protection of low density lipoprotein from peroxynitrite-mediated oxidations at physiologic CO2, J. Agric. Food Chem., 52, 2866, 2004. 

Lynn, D.G. and Chang, M., Phenolic signals in cohabitation implications for plant development, Anna. Rev. Plant Physiol Plant Mol. Biol, 41, 497, 1990. 

Elliger, C.A. and Halloin, J.M., Phenolics induced in Beta vulgaris by Rhizoctonia solani infection. Phytochemistry, 37, 691, 1994. 

Fig. 6.112. Comparison of coverage vs. potential curves for (o) experimental and ( ) theoretical [Eq. (6.270)] results predicted by the adsorption model for the adsorption of (a) 10-5 M phenol and (b) 10""4 M n-valeric acid on platinum electrodes. Under these experimental conditions, the pzc was found to be at about 0.35 V. (Reprinted from J. O M. Bockris and K. T. Jeng, J. Electroanal. Chem. 330 541, Copyright 1992, Figs. 18,19, and 20, with permission of Elsevier Science.)...

Contact adhesives -phenolic resins m [PHENOLIC RESINS] (Vol 18)... 

Oil filters -phenolic resins m [PHENOLIC RESINS] (Vol 18) -source of ferrous scrap [RECYCLING - METALS - FERROUS METALS] (Vol 20)... 

Fig. 2.10 Amounts of 02 consumed as a result of photocatalytic reactions in ethanol-containing aqueous solution, with and without 0.1 M phenol present, under UV irradiation for 1 min. The amount of 02 consumed was estimated using a finite difference method from the oxygen concentration vs. time curves (light intensity, 2.5 mW/cm2 microelectrode potential, -1 V vs. SCE).

My research on AOPs began over 12 years ago at the University of Delaware. When I worked on the degradation of phenols by a visible photon/ CdS system, I had to wake up at midnight in order to take samples from a photocatalytic reactor because the reaction half time in degrading 0.001-M phenol is about 1 day. After I found that Fenton s reagent was an extremely... 

The UV irradiation of phenol in the presence of nitrite (pH around neutrality) yields 4-nitrosophenol, catechol, hydroquinone, 1,4-benzoquinone, 2-nitrophenol and 4-nitrophenol [44,62,78,79]. It is interesting to observe that nitrophenols do not form in appreciable amount upon irradiation of 1.0 x 10-3 M phenol and nitrite, while relevant nitrophenol formation can be observed for [N02 ] > 1.0 x 10-3 M [44,79]. The formation of catechol, hydroquinone and 1,4-benzoquinone is most likely due to the photoinduced generation of hydroxyl (reactions 17 and 18). The relevant processes are initiated by hydroxyl attack on phenol (H-Ph-OH) in the presence of oxygen ([78,79] HO - Ph - OH catechol or hydroquinone, O = Ph = O 1,4-benzoquinone) ... 

Fig. 2 Initial formation rates of 2-nitrophenol and 4-nitrophenol upon nitrate irradiation at 312 nm as a function of pH. Initial conditions 1.0 x 10 3 M phenol, 0.10 M NaN03, photon flux in solution 3.6 x 10 7 F.in s 1. Ein = Einstein (1 Einstein = 1 mole of photons)...

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