Nitrophenols aminophenols

Uses. (9-Nitrochlorobenzene is used in the synthesis of azo dye intermediates such as o-chloroaniline (Fast YeUow G Base), i9-nitroani1ine (Fast Orange GR Base), o-anisidine (Fast Red BB Base), o-phenetidine, and (9-aminophenol (see Azo dyes). It also is used in corrosion inhibitors, pigments, and agriculture chemicals. -Nitrochlorobenzene is used principally in the production of intermediates for azo and sulfur dyes. Other uses include pharmaceuticals (qv), photochemicals, mbber chemicals (qv), and insecticides (see Insectcontroltechnology). Typical intermediates manufactured from the para isomer are -lutioaruline (Fast Red GC Base), anisidine, -aminophenol, -nitrophenol, -phenylenediamine, 2-chloro-/)-anisidine (Fast Red R Base), 2,4-dinitrochlorobenzene, and l,2-dichloro-4-nitrobenzene. 

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. 

Ditrophenol, -nitropbenol, C H NOj. Colourless needles m.p. 114 C. Prepared as 2-nitrophenol. Reduction with iron and hydrochloric acid gives 4-aminophenol. 

Reduction to aminophenol. Reduce about 0 5 g. of o-nitrophenol with cone. HCl and tin as described on p. 385. After a few minutes the yellow molten o-nitrophenol disappears completely, the solution becoming homogeneous and colourless due to the formation of 0-aminophenol (which is soluble in HCl). Cool and add 30% aqueous NaOH solution note that a white precipitate is first formed and then redissolvcs in an excess of NaOH, and that the solution does not develop an orange coloration, indicating that the nitro-group has been reduced. 

A) Benzoyl Derivative. Since acetylation and benzoylation do not always proceed smoothly with nitrophenols, it is best to reduce them to the aminophenol as in (3) above. Add an excess of 20% aqueous sodium hydroxide to the reaction mixture after reduction, cool and then add a small excess of benzoyl chloride, and shake in the usual way. The dibenzoyl derivative wiU separate. Filter, wash with water and recrystalUse. (M.ps., p. 551.)... 

Aminophenols are either made by reduction of nitrophenols or by substitution. Reduction is accompHshed with iron or hydrogen in the presence of a catalyst. Catalytic reduction is the method of choice for the production of 2- and 4-aminophenol (see Amines BY reduction). Electrolytic reduction is also under industrial consideration and substitution reactions provide the major source of 3-aminophenol. 

Iron Reduction. The reduction of nitrophenols with iron filings or turnings takes place in weakly acidic solution or suspension (30). The aminophenol formed is converted to the water soluble sodium aminopheno1 ate by adding sodium hydroxide before the iron-iron oxide sludge is separated from the reaction mixture (31). Adjustment of the solution pH leads to the precipitation of aminophenols, a procedure performed in the absence of air because the salts are very susceptible to oxidation in aqueous solution. 

Insoluble red lakes are formed as by-products which decrease yields when 2-nitrophenol [88-75-5] is reduced with iron. Consequendy, the iron reduction of this nitro compound to 2-aminophenol is of minor industrial importance today. 

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). 

Objective To examine the effect of ultrasound on the degradation of phenol, p-aminophenol, and p-nitrophenol. 

Result The sonochemical degradation of phenol is less than either p-aminophe-nol or p-nitrophenol. However, the sonochemical degradation of p-aminophenol is more than that of p-nitrophenol. This difference in the degradability of individual organic moieties can be understood / explained as below. 

Hemoglobin is another heme-containing protein, which has been shown to be active towards PAH, oxidation in presence of peroxide [420], This protein was also modified via PEG and methyl esterification to obtain a more hydrophobic protein with altered activity and substrate specificity. The modified protein had four times the catalytic efficiency than that of the unmodified protein for pyrene oxidation. Several PAHs were also oxidized including acenaphthene, anthracene, azulene, benzo(a)pyrene, fluoranthene, fluorene, and phenanthrene however, no reaction was observed with chrysene and biphenyl. Modification of hemoglobin with p-nitrophenol and p-aminophenol has also been reported [425], The modification was reported to enhance the substrate affinity up to 30 times. Additionally, the solvent concentration at which the enzyme showed maximum activity was also higher. Both the effects were attributed to the increase in hydrophobicity of the active site. 

Plant. Oat plants were grown in two soils treated with [ CJparathion. Less than 2% of the applied [ CJparathion was translocated to the oat plant. Metabolites identified in both soils and leaves were paraoxon, aminoparaoxon, aminoparathion, p-nitrophenol, and an aminophenol (Fuhremann and Lichtenstein, 1980). 

The following metabolites were identified in a soil-oat system paraoxon, aminoparathion, 4-nitrophenol, and 4-aminophenol (Lichtenstein, 1980 Lichtenstein et al., 1982). Mick and Dahm (1970) reported that Rhizobium sp. converted 85% [ CJparathion to aminoparathion and 10% diethyl phosphorothioic acid in 1 d. 

CASRN 15457-05-3 molecular formula C13H7F3N2O5 FW 328.20 Chemical/Physical. When fluorodifen as an aqueous suspension was irradiated using UV light (A, = 300 nm), 4-nitrophenol and 4-(trifluoromethyl)-2-aminophenol formed as the major products (>90% of total product formation). In addition, 4-(trifluoromethyl)-2-nitrophenol formed as a minor product (<1%) as well as 4-hydroxy-3-nitrobenzoic acid. In methanol, photolysis of fluorodifen yielded 4-nitrophenol and 2-amino-4-(trifluoromethyl)anisole. In cyclohexanone, 4-nitrophenol and 3-(trifluoromethyl)nitrobenzene were formed (Ruzo et al., 1980). 

Nitro alcohols were reduced to amino alcohols by catalytic hydrogenation over platinum [632] and with iron [JJ9], and nitrosophenols [255] and nitro-phenols [256] to aminophenols with sodium hydrosulfite, sodium sulfide [238] or tin [176]. Bromine atoms in 2,6-di-bromo-4-nitrophenol were not affected [176]. 

DNB included m-nitrophenol, m-aminophenol, resorcinol, fumaricacid, and some volatile fatty acids (Dey and Godbole 1986). A pure culture of Rhodococcus sp. isolated from soils contaminated with nitroaromatics was capable of using 1,3-DNB as a sole source of nitrogen. This culture metabolized 1,3-DNB to nitrite via a 4-nitrocatechol pathway even in the presence of high amounts of ammonia (Dickel and Knackmuss 1991). 

Ingestion of alcohol aggravates the toxic effects of nitrobenzene. In general, higher ambient temperatures increase susceptibility to cyanosis from exposure to methemoglobin-forming agents." p-Nitrophenol and p-aminophenol are metabolites of nitrobenzene, and their presence in the urine is an indication of exposure."... 

Sulfur Bake. The yellow, orange, and brown sulfur dyes belong to this group. The dyes are usually made from aromatic amines, diamines, and their acyl and nuclear alkyl derivatives. These may be used in admixture with nitroanilines and nitrophenols or aminophenols to give the desired shade. The color formed is said to be the result of the formation of the thiazole chromophore, evident in dye structure (1). 

---