100-02-7 4-Nitrophenol

Other Names Phenol, o-nitro- 2-Hydroxynitrobenzene 2-Nitrophenol NSC 1552 o-Hydroxyni-trobenzene o-Nitrophenol CA Index Name Phenol, 2-nilro-CAS Registry Number 88-75-5 Merck Index Number 6620 Chemical Structure 

Chemical/Dye Class Nitro Molecular Formula C6H5NO3 Molecular Weight 139.11 pH Range 5.0-7.0 

Solubility Sparingly soluble in water soluble in ethanol, ether, benzene Melting Point 44 5°C Boiling Point 214-216°C Synthesis Synthetic methodsi-12 

Major Applications High voltage capacitors,inks, 5 energetic materials, corrosion inhibitors,fertilizer, food storage, enzyme assays, detecting microorganisms,22 immunother- 

Safety/Toxicity Chemical toxicity,25.2 ecotoxicity, acute toxicity, toxicology, mutagenicity, immunotoxicology,3i genotoxicity,32hepatotoxicity,33 cytotoxicity,33 phytotoxidty  

Add 101 g. (55 ml.) of concentrated sulphuric acid cautiously to 75 ml. of water contained in a 1 htre beaker, and introduce 35 g. of finely-powdered wi-nitroaniline (Section IV,44). Add 100-150 g. of finely-crushed ice and stir until the m-nitroaniUne has been converted into the sulphate and a homogeneous paste results. Cool to 0-5° by immersion of the beaker in a freezing mixture, stir mechanically, and add a cold solution of 18 g. of sodium nitrite in 40 ml. of water over a period of 10 minutes until a permanent colour is immediately given to potassium iodide - starch paper do not allow the temperature to rise above 5-7° during the diazotisation. Continue the stirring for 5-10 minutes and allow to stand for 5 minutes some m-nitrophenjddiazonium sulphate may separate. Decant the supernatant Uquid from the solid as far as possible. 

While the diazotisation is in progress, cautiously add 165 ml. of concentrated sulphuric acid to 150 ml. of water in a 1-litre round-bottomed flask. Heat the mixture just to boiling. Add the supernatant Uquid (diazonium solution) from a separatory funnel supported over the flask at such a rate that the mixture boils very vigorously (about 30 minutes). Then add the residual damp soUd (or suspension) in small portions avoid excessive frothing. When aU the diazonium salt has been introduced, boil for a further 5 minutes and pour the mixture into a 1-Utre beaker 

Benzene may be prepare l similarly from plienyldiazonium chloride (Section IV,60). 

Compare the conditions used in the nitration of phenol with those used in making nitrobenzene (experiment 170, page 139), dinitrobenzene (experiment 172, page 141), and nitroacetanilide (experiment 219, page 182). 

—The yields are small in this preparation on account of the fact that compounds other than o- and p-nitrophenol are formed among these are substances of a tarry nature from which it is difficult to separate the para-compound. It is on this account that special precautions are necessary in order to obtain p-nitrophenol in a crystalline condition, 

Add 101 g. (55 ml.) of concentrated sulphuric acid cautiously to 75 ml. of water contained in a 1 litre beaker, and introduce 35 g. of finely-powdered m-nitroaniline (Section IV,44). Add 100-150 g. of finely-  

10 minutes until a permanent colour is immediately given to potassium  

Form Supplied in yellow solid, commercially available. Purification crystallizes as yellow needles or prisms from ethanol or ether. 

Handling, Storage, and Precautions moderately toxic by inhalation and skin absorption. 

Preparation of Active Esters for Peptide Synthesis. Esters of o-nitrophenol, prepared by the 1,3-DicyclohexykarbodUmide 

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Prepared by reduction of 4-nitrophenol or 4-nitrosophenoi. Can be diazotized and used as a first component in azo-dyes. Chief outlet is for sulphur dyes in which it is fused with sodium polysulphides. L/sed as a photographic developer. 

Bright yellow needles m.p. 45 C, b.p. 2 4°C. Prepared together with 4-nitrophenol by careful nitration of phenol. Sodium sulphide reduces it to 2-aminophenol which is used in dyestuffs and photographic processes. 

Amino-4-nitrophenol. This derivative, 2-hydroxy-5-nitroani1ine (9), forms orange prisms from water. These prisms are hydrated with one water of crystallization, mp 80—90°C, and can be dehydrated over sulfuric acid to the anhydrous form, mp 143 —145°C. The compound is soluble in ethanol, diethyl ether, acetic acid, and warm benzene and slightly soluble in water. 

Production is by the acetylation of 4-aminophenol. This can be achieved with acetic acid and acetic anhydride at 80°C (191), with acetic acid anhydride in pyridine at 100°C (192), with acetyl chloride and pyridine in toluene at 60°C (193), or by the action of ketene in alcohoHc suspension. 4-Hydroxyacetanihde also may be synthesized directiy from 4-nitrophenol The available reduction—acetylation systems include tin with acetic acid, hydrogenation over Pd—C in acetic anhydride, and hydrogenation over platinum in acetic acid (194,195). Other routes include rearrangement of 4-hydroxyacetophenone hydrazone with sodium nitrite in sulfuric acid and the electrolytic hydroxylation of acetanilide [103-84-4] (196). 

Alkylphenols, ammonia, asbestos, chlorinated paraffins, 4-chloroaniline, cyanide, detergents, di- -butyl phthalate, polyaromatic hydrocarbons (PAHs e.g. anthracene, benzopyrene, methylcholanthrene, /i-naphthoflavone), nitrate, nitrite, petroleum oil, phenol, pentachlorophenol, 4-nitrophenol, dinitro-o-cresol, polychlorinated biphenyls (PCBs especially coplanar), polychlorinated dioxins, polybrominated naphthalenes, /i-sitosterol, sulfide, thiourea, urea, acid water, coal dust... 

Dichloro-4-nitrophenol [618-00-4] M 208.0, m 125°, pK 3.55. Crystd from EtOH and dried in vacuo over anhydrous MgSOa. 

Nitrophenol [100-02-7] M 139,1, m 113-114 , pK 7.16. Crystd from water (which may be acidified, e.g. N H2SO4 or 0.5N HCl), EtOH, aqueous MeOH, CHCI3, benzene or pet ether, then dried under vacuum over P2O5 at room temperature. Can be sublimed at 60°/10 m. 

Trifluoromethyl-4-nitrophenol [88-30-2] M 162.1, m 81°, pK si 6.1. Crystd from benzene or from pet ether/ benzene mixture. 

Disodium 4-nitrophenylphosphate (6H2O) [4264-83-9] M 371.1 Dissolve in hot aqueous MeOH, filter and ppte by adding Me2CO. Wash the solid with Me2CO and repeat the purification. Aq MeOH and Et20 can also be used as solvents. The white fibrous crystals contain less than 1% of free 4-nitrophenol [assay J Biol Chem 167 57 1947]. 

Phenol has different chemical properties from those of typical alcohols. Display the electrostatic potential map for phenol. Does this suggest that phenol is likely to be a stronger or weaker acid than any of the compounds discussed above Compare the electrostatic potential map for 4-nitrophenol to that for phenol. What effect does substitution by nitro have on acid strength Explain your result by considering charge delocalization in the conjugate base. Draw all reasonable Lewis structures for phenoxide anion and for 4-nitrophenoxide anion. Which is more delocalized Is this consistent with experimental pKa s ... 

For example. Figure 13.13 shows the chromatogram obtained when 200 ml of tap water was spiked at levels of 1 p.g 1 of such pesticides. The limits of detection achieved by using this method were between 0.05 and 0.5 p.g 1 although more polar compounds Such as vamidothion or 4-nitrophenol could not be determined (61). 

The reaction with 4-nitrophenol and pentafluorophenol in the presence of KF-18-crown-6 has been investigated. Pentafluorophenoxide anion was found to be a better leaving group [82JFC(20)439]. Alkali metal fluorides on graphite can act as catalysts for nucleophilic substitution of pentafluor-opyridine [90JFC(46)57]. 

Nitrophenols, nitroaminotoluenes, A,A-dimethylnitroanilines, chloronitrotoluenes, chloronitroanilines, nitronaphthalenes. di-nitrotoluenes, dinitroanilines, dinitrophenols, dinitrochloroben-zenes, dichloronitrotoluenes, chlorodinitroanilines, dinitronaph-thalenes, and trichloronitrotoluenes... 

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... 

Mononitrophenolsulfonic Acids, 02N.C6H3(0H).S03H, mw 273.22. Several acids are described in Beilstein, of which only the o- and p- are formed as intermediate products in the manuf of PA from phenol o- (or l,4,2-)Nitrophenolsulfonic Add. Crysts with 3H20 mp, loses H20 at 100°and then decomps at about 110° can be prepd by treating 4-nitrophenol with coned sulfuric acid Refs 1) Beil 11,237, (53) [132] 2) F. 

Analogies for such a mechanism in diazotization are found in the nitrous acid-catalyzed nitration of A,A-dimethylaniline, mesitylene, 4-nitrophenol, and some related compounds, which were investigated by 15N NMR spectroscopy in Ridd s group (Ridd and Sandall, 1981 Ridd et al., 1992 Clemens et al., 1984a, 1984b, 1985 Johnston et al., 1991 review Ridd, 1991). Ridd and coworkers were able to demonstrate clearly that not only the nitration proper, but also the preceding C-nitrosation, is accompanied by a marked 15N nuclear polarization. This was at-... 

Hammett (1937) observed that the value of the constant op for a nitro group as obtained from the acidity constant of 4-nitrobenzoic acid (crp = 0.78) was applicable, for example, to the rate of hydrolysis of ethyl 4-nitrobenzoate, but not to the acidity constants of 4-nitrophenol and 4-nitroanilinium ion. These two acidities were compatible only with significantly higher constants denoted by op (1.21 and 1.27, respectively). This was (correctly) interpreted as resulting from the donor-acceptor interaction represented by the mesomeric structures 7.7. 

The observations that addition of pyridine increases the rate of decomposition, shifts the order of reaction from unity to zero, and considerably diminishes formation of 4-nitrophenol also warrants attention. This is compatible with the superior electron-donor properties of pyridine as compared to DMSO (Gutmann, 1976, 1977) generation of the corresponding diazopyridinium cation in one or several of the forms corresponding to 8.59 and 8.60 competes with formation of 8.58. 

Kinetic studies have been made on the nitration of anisole, 4-chloroanisole, 4-nitrophenol and mesitylene105. For anisole the kinetics are complicated by demethylation for 4-chloroanisole, nitration by 4-10 M nitric acid in glacial... 

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