Phenols 2.4- dinitrophenol

Titanium ions can also he used as redox catalysts for the indirect cathodic reduction of nitro compounds (417). The electroreduction is carried out in an H20-H2S04/Ti(S04)2-(Pb/Cu) system at 45 80°C under 5 20Am . Nitrobenzene, dinitrobenzene, nitrotoluene, 2,4-dinitrotoluene, 2-nitro-m-xylene, nitro-phenol, 2,4-dinitrophenol, nitrophenetole, o-nitroanisole, 4-nitrochlorotoluene, ni-trobenzenesulfonic acid, and 4,4 -dinitro-stilbene-2,2 -disulfonic acid can all be reduced by this procedure to the corresponding amino compounds (418) in good yields (Scheme 146) [513-516]. Tin... 

The pH values of efficient extraction correspond to the pH range where the molecular form of the respective phenol dominates. The recovery of 4-nitro-phenol, 2,4-dinitrophenol, 2,6-dinitrophenol, 4-chlorophenol, 1-naphthol, and 2-naphthol is above 90% (the ratio of aqueous organic phase volume is 3 1). The extraction of naphthol and 4-chlorophenol is significant even at pH > pffa, more than 40 and 24% at pH > 10, respectively. Recovery of picric acid (2,4,6-trinitrophenol) is about 90% at pH 1.5-12.0, where the anionic form of picric acid dominates. Obviously, the high extraction is caused by high hydrophobicity of picrate anions. Recovery of the phenol itself and diatomic phenols, catechol and resorcinol is rather moderate (79,58, and 20%, respectively pH 1-7), which could be explained by relatively high hydrophi-licity of these compounds. 

Problem 24.6 How do you account for the fact that, unlike most phenols, 2,4-dinitrophenol and 2,4,6-trinitrophenol are soluble in aqueous sodium bicarbonate ... 

It is obvious that the slopes of the regressions in TABLE 4 vary significantly. But it was quite satisfactory that the regression equation we found for phenols (equation 3) proved to be nearly similar to the relationship given by Neely et al. (1974). Equation (3) is also valid for phenols bearing the structure element 2,4-dinitro-substitution but then a constant factor has to be subtracted as shown in equation (5). With respect to the toxicity of phenols, dinitrophenols (2,5-dinitro-phenol and 2,4-dinitro-sec-butylphenol) were only poorly fitted to a QSAR based solely upon log P (Lipnick et al. 1986). But whereas for toxicity there is an explanation for the higher toxicity of the dinitrophenols (i.e., the inhibition of oxidative phosphorylation), we cannot, as yet, explain their much smaller accumulation compared to other phenols. 

RCH(OH)=CHCOR or -keto esters RCH(OH)=CHCOOR ) dissolve in dilute sodium hydroxide solution, i.e., contain an acidic group of sufficient strength to react with the alkah. Carboxyhc acids and sulphonic acids are soluble in dilute solutions of sodium bicarbonate some negatively-substituted phenols, for example, picric acid, 2 4 6-tribromo-phenol and 2 4-dinitrophenol, are strongly acidic and also dissolve in dilute sodium bicarbonate solution. 

The procedure of simultaneous extracting-spectrophotometric determination of nitrophenols in wastewater is proposed on the example of the analysis of mixtures of mono-, di-, and trinitrophenols. The procedure consists of extraction concentrating in an acid medium, and sequential back-extractions under various pH. Such procedures give possibility for isolation o-, m-, p-nitrophenols, a-, P-, y-dinitrophenols and trinitrophenol in separate groups. Simultaneous determination is carried out by summary light-absorption of nitrophenol-ions. The error of determination concentrations on maximum contaminant level in natural waters doesn t exceed 10%. The peculiarities of application of the sequential extractions under fixed pH were studied on the example of mixture of simplest phenols (phenol, o-, m-, />-cresols). The procedure of their determination is based on the extraction to carbon tetrachloride, subsequent back-extraction and spectrophotometric measurement of interaction products with diazo-p-nitroaniline. 

Multiple substitution by strongly electron-withdrawing groups greatly increases the acidity of phenols, as the pK values for 2,4-dinitrophenol (4.0) and 2,4,6-trinitrophenol (0.4) in Table 24.2 attest. 

Figure 13.15 Chromatograms obtained by on-line ti ace enrichment of 50 ml of Ebro river water with and without the addition of different volumes of 10% Na2S03 solution for every 100 ml of sample (a) blank with the addition of 1000 p.1 of sulfite (b) spiked with 4 p.g 1 of the analytes and 1000 p.1 of sulfite (c) spiked with 4 p.g 1 of the analytes and 500 p.1 of sulfite (d) spiked with 4 p.g 1 of the analytes without sulfite. Peak identification is as follows 1, oxamyl 2, methomyl 3, phenol 4, 4-niti ophenol 5, 2,4-dinitrophenol 6, 2-chlorophenol 7, bentazone 8, simazine 9, MCPA 10, atrazine. Reprinted from Journal of Chromatography, A 803, N. Masque et ai, New chemically modified polymeric resin for solid-phase extraction of pesticides and phenolic compounds from water , pp. 147-155, copyright 1998, with permission from Elsevier Science.

Phenol 2,4,6-trichlorophenol p-chloro-m-cresol 2-chlorophe-nol 2,4-dichlorophenol 2,4,-dimethylphenol 2-nitrophenol 4-nitrophenol 2,4-dinitrophenol and pentachlorophenol... 

Phenol has been used as a starting material for the prepn of such expls as Dinitrophenol,... 

Dinitrophenols. (02N)2.C6H3 -OH, mw 184.11, N 15.22%, OB to COj —78.30%. Six isomers are possible, and all are expl. The most important one is 2,4-Dinitrophenol, which has been used as a component of various expl mixts. The expl properties of 2,5- and 2,6-Dinitro-phenol have also been examined... 

Mor alpha-) Dinitrophenol- Yel orthorhombic crysts from w, leaflets from ale mp 112—14° bp (decomp) d 1.683g/cc at 24°, 1.4829 at 72.5/4°. Sublimes when carefully heated volatile with steam. Can be prepd by the nitration of phenol, but this method is not considered commercially practicable because of partial decompn of the phenolic ring. A better method is by hydrolysis under pressure of 2,4-dinitrochloro-benzene, which in turn can be obtained by nitrating chlorobenzene. Other methods are given in Ref 1... 

C6H2(N02)30H (NH SaQs C02+HN03+HCN When mildly reduced, for example with Na sulfide or hydrosulfite or with ferrous sulfate, PA is converted into picramic acid, a very useful intermediate in the dyestuffs industry and a starting material for the preparation of Diazo-dinitrophenol, a primary expl (see Vol 2, B59-L). Stronger reduction may lead to the formation of triamino phenol... 

VII. Preparation. There are two industrial methods of manufg PA 1) nitration of Phenol 2) nitration of dinitrophenol prepd by hydrolysis of chloro dinitrobenzene... 

Recent examples of this synthesis are of two types. The first involves condensation of the activated phenol, 2-amino-4,6-dinitrophenol (346a) with 2-dimethyl-amino-3,3-dimethyl-3//-azirine (346b) (in MeCN, 0°C- 20°C, A, 24 h) to afford a separable mixture of four products, one of which was 2-dimethylamino-3,3-dimethyl-5,7-dinitro-3,4-dihydroquinoxaline (346c) ( 20% yield) and another its hydrolysis product, 3,3-dimethyl-5,7-dinitro-3,4-dihydro-2(l//)-quinoxalinone (346d) ( 8%) the mechanism of such condensations has been discussed. ... 

The permanganate oxidation of phenols is complicated by the intervention of lower oxidation states of manganese, (c/. the oxidation of toluene, p. 298). For example, the oxidation of 2,6-dinitrophenol in weakly acidic solution displays an induction period, following second-order kinetics thereafter. However, addition of potassium fluoride inhibits reaction almost completely, but manganous ions strongly accelerate it. 

Ebert S, P-G Rieger, H-J Knackmuss (1999) Function of coenzyme P420 in aerobic catabolism of 2,4,6-trinitro-phenol and 2,4-dinitrophenol by Nocardiodes simplex FJ2-1 A. J Bacterial 181 2669-2674. 

Nitrophenols are phytotoxic, and dinoseb (6-iec-butyl-2,4-dinitrophenol) has been used as a herbicide, while nitrophenols have been detected in rainwater and plausible mechanisms for their abiotic formation have been proposed (Kohler and Heeb 2003 Vione et al. 2005). The pathway for the degradation of phenols with a single nitro group depends on the position of the substituents, while... 

They are soluble in 6 per cent, sodium hydroxide solution and insoluble in 5 per cent, sodium bicarbonate solution they are precipitated from their solutions in aqueous sodium hydroxide by carbon dioxide. [Exceptions the presence of certain negative groups in phenols increases the acidity to such an extent that they may dissolve in sodium bicarbonate solution, for example, 2 4-dinitrophenol, picric acid and s-tribromophenol.]... 

At first we determined, by means of the DVP method, ifTMAX of 2,4-dinitro-phenolate, 2,5-dinitrophenol picrate, acetate and benzoate, which lay between 10 3 and 10 5. Next, separate potentiometric titrations of 2,5-dinitrophenol and picric acid were carried out on the basis of the previously known (see above) ptfax = 6.5 and P hx2- = 100 for 2,5-dinitrophenol and p.fiTHX = 3.0 for picric acid, we calculated titration curves for estimated values of 0 and obtained, for the best fit between the experimental and calculated curves, K o = 10 21 for both 2,5-dinitrophenol and picric acid. In both instances changing fTMA0H for 1 to 10 6 did not alter the calculated titration curve. Finally, for potentiometric titrations of other acids with TMAOH while using / TMAX values from DVP results, in addition to Kn 0 = 10 21, we obtained the best fit between the experimental and calculated curves again when pifbenzoic acid = 1 (see Fig. 4.12)... 

The manufacture of sulfur dyes involves sulfurisation processes, the chemistry of which remains rather mysterious and may arguably be considered still to be in the realms of alchemy The processes involve heating elemental sulfur or sodium polysulfide, or both, with aromatic amines, phenols or aminophenols. These reactions may be carried out either as a dry bake process at temperatures between 180 and 350 °C or in solvents such as water or aliphatic alcohols at reflux or at even higher temperatures under pressure. C. I. Sulphur Black 1, for example, is prepared by heating 2,4-dinitrophenol with sodium polysulfide. 

Dinitrophenol 4,6 -Dinitro-o -cresol V-Nitrosodimethylamine V-Nitrosodiphenylamine V-Nitrosodi-n-propylamine Pentachlorophenol Phenol... 

Mitochondria do three things oxidize substrates, consume oxygen, and make ATP. Uncouplers prevent the synthesis of ATP but do not inhibit oxygen consumption or substrate oxidation. Uncouplers work by destroying the pH gradient. The classic uncoupler is dinitrophenol (DNP). This phenol is a relatively strong acid and exists as the phenol and the phenolate anion. 

Pikrinsaure wird durch Losen von Phenol in Schwefelsaure und Nitrie-rung der entstandenen Phenoldisulfosaure mit Salpetersaure Oder durch Weiternitrieren von Dinitrophenol (aus Dinitrochlorbenzol) her-gestellt. Das Rohprodukt wird durch Waschen mit Wasser gereinigt. 

By further nitration with more concentrated acid o- and p-nitro-phenols are converted into the same 2 4-dinitrophenol, and finally into picric acid. Polynitro-derivatives of benzene, such as picric acid and trinitrotoluene, can be caused to explode by detonation with mercury fulminate or lead azide. (The formulae of these two compounds should be written.) They are endothermic, i.e. the oxygen of the nitro-group can oxidise carbon and hydrogen within the molecule and heat is liberated. This intramolecular combustion is rather considerable in the case of picric acid, which is decomposed in accordance with the equation ... 

Rice PJ, Drewes CD, Klubertanz TM, et al. 1997. Acute toxicity and behavioral effects of chlorpyrifos, permethrin, phenol, strychnine, and 2,4-dinitrophenol to 30-day-old Japanese Medaka (Oryzias latipes). Environ Toxicol Chem 16 696-704. 

Crystal violet Thymol blue 2,4-Dinitrophenol Bromophenol blue Bromocresol green Methyl red Alizarin Bromothymol blue Phenol red Phenolphthalein Alizarin yellow R... 

Titanium dioxide suspended in an aqueous solution and irradiated with UV light X = 365 nm) converted benzene to carbon dioxide at a significant rate (Matthews, 1986). Irradiation of benzene in an aqueous solution yields mucondialdehyde. Photolysis of benzene vapor at 1849-2000 A yields ethylene, hydrogen, methane, ethane, toluene, and a polymer resembling cuprene. Other photolysis products reported under different conditions include fulvene, acetylene, substituted trienes (Howard, 1990), phenol, 2-nitrophenol, 4-nitrophenol, 2,4-dinitrophenol, 2,6-dinitro-phenol, nitrobenzene, formic acid, and peroxyacetyl nitrate (Calvert and Pitts, 1966). Under atmospheric conditions, the gas-phase reaction with OH radicals and nitrogen oxides resulted in the formation of phenol and nitrobenzene (Atkinson, 1990). Schwarz and Wasik (1976) reported a fluorescence quantum yield of 5.3 x 10" for benzene in water. 

Photolytic. A carbon dioxide yield of 19.7% was achieved when bromobenzene adsorbed on silica gel was irradiated with light (X >290 nm) for 17 h (Freitag et al., 1985). Irradiation of bromobenzene in air containing nitrogen oxides gave phenol, 4-nitrophenol, 2,4-dinitrophenol, 4-bromophenol, 3-bromonitrobenzene, 3-bromo-2-nitrophenol, 3-bromo-4-nitrophenol, 3-bromo-6-... 

Acetamido-4-amino-6-chloro-s-triazine, see Atrazine Acetanilide, see Aniline, Chlorobenzene, Vinclozolin Acetic acid, see Acenaphthene, Acetaldehyde, Acetic anhydride. Acetone, Acetonitrile, Acrolein, Acrylonitrile, Aldicarb. Amyl acetate, sec-Amyl acetate, Bis(2-ethylhexyl) phthalate. Butyl acetate, sec-Butyl acetate, ferf-Butyl acetate, 2-Chlorophenol, Diazinon. 2,4-Dimethylphenol, 2,4-Dinitrophenol, 2,4-Dinitrotoluene, 1,4-Dioxane, 1,2-Diphenylhydrazine, Esfenvalerate. Ethyl acetate, Flucvthrinate. Formic acid, sec-Hexyl acetate. Isopropyl acetate, Isoamyl acetate. Isobutyl acetate, Methanol. Methyl acetate. 2-Methvl-2-butene. Methyl ferf-butvl ether. Methyl cellosolve acetate. 2-Methvlphenol. Methomvl. 4-Nitrophenol, Pentachlorophenol, Phenol. Propyl acetate. 1,1,1-Trichloroethane, Vinyl acetate. Vinyl chloride Acetoacetic acid, see Mevinphos Acetone, see Acrolein. Acrylonitrile. Atrazine. Butane. 

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