Nitrophenols


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The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Nitrophenols

 

products of the substitution of nitro groups, —NO2, for the hydrogen atoms in the phenol ring, C6H5OH. The nitrophenols shown in Table 1 are of commercial significance.

Table 1. Properties of commercial nitrophenols
 Melting pointC)Density (g/cm3)
*Temperature (°C)
o-Nitrophenol...................44.91.29 (40)*
p-Nitrophenol...................1141.48 (20)
2,4-Dinitrophenol.................1131.68 (24)
2,4,6-Trinitrophenol ...............122.51.76(20)

Nitrophenols are crystalline substances. In industry, ortho- and para-nitrophenols are produced by heating the corresponding nitrochlorobenzenes with an aqueous solution of sodium hydroxide; 2,4-dinitrophenol (2,4-D) is obtained in an analogous manner from 2,4-dinitrochlorobenzene. These nitrophenols are blood poisons, but they also act on the nervous system and irritate the mucous membranes and skin, leading to dermatitis and chronic eczema. For example, the maximum permissible concentration of 2,4-D in air in work areas is 0.05 mg/m3. The main use of ortho- and para-nitrophenols is in the production of ortho- and para-aminophenols. Picric acid, sulfur black dye, and 2,4-diaminophenol (amidol developer) are produced from 2,4-D; it is also used as a herbicide.

Picric acid, or 2,4,6-trinitrophenol (2,4,6-T), was used as a yellow dye for silk (the first synthetic organic dye) and as an explosive (melinite and lyddite); it is poisonous, and its maximum permissible concentration in air in work areas is 1 mg/m3. With metals, 2,4,6-T forms dangerously explosive, easily flammable salts called picrates.

REFERENCE

Orlova, E. Iu. Khimiia i tekhnologiia brizantnykh vzryvchatykh ve-shchestv, 2nd ed. Leningrad, 1973.

D. A. GUREVICH

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
Keywords: chloromequat, nitrophenols, trinexsapac-ethyl, nitrogen dose, precipitation conditions, spring cereal.
Experimental treatments included herbicides: (i) MCPA + dicamba (Chwastox Turbo 340 SL), (ii) dicamba + triasulfuron (Lintur 70WG), (iii) florasulam +2,4-D (Mustang 306 SE) and biostimulants: (i) Kelpak SL (32,26% algae Ecklonia maxima extract) and (ii) Asahi SL composed of nitrophenols (sodium ortho nitrophenol, sodium para nitrophenol, sodium 5-nitroguaiacolate).
Silver nitrate (AgN[O.sub.3]), cupric nitrate (Cu[(N[O.sub.3]).sub.2]), and nitrophenols were obtained from Merck Chemicals.
Typically, a solution containing 0.125 g of nitrophenols with 20 mL of hydrazine hydrate was heated to 80-100[degrees]C in a three-necked flask connected to a condenser.
Stupak, "Determination of aromatic acids and nitrophenols in atmospheric aerosols by capillary electrophoresis," Journal of Chromatographic Science, vol.
In studies of adsorption of phenol and nitrophenols on carbonaceous materials, it was found that the adsorption of phenolics followed the sequence 2,4-DNP >2-NP > phenol, and this behavior is associated to pH from the solution and the content of surface groups on the activated carbon.
Moreover, nitrophenols and methylphenol sources have been related to vehicular emissions [6,7] Phenols may occur naturally via biodegradation of humic products, for example tannins and lignins [8].
The decrease in current response also indicates that the electrode cannot be applied for the detection of nitrophenols. The peak potentials for catechol and hydroquinone were less than 0.1V and they showed no effect on the response for phenol.
P Singh, "Bacterial degradation of nitrophenols and their derivatives," Journal of Hazardous Materials, vol.
Nitrophenols (NPs) are primarily concerned toxic pollutants by the United States Environmental Protection Agency (USEPA) [17], as these compounds have been found in industrial and agricultural wastes.
Degradation of aqueous nitrophenols and nitrobenzene by means of the Fenton reaction.
Some phenols in the soils originate from the transformation of pesticides such as 2.4-dichlorophenoxyacetic acid (2.4-D),4-chloro-2methylphenoxyacetic acid (MCPA), 2,4,5-trichloro-phenoxyacetic acid (2,4,5-T), 2-buthyl-4,6-dinitrophenol (dinoseb), and phenolic biocides like pentachlorophenol (PCP) [8] and from atmospheric depositions [9] Moreover, nitrophenols and methylphenol sources have been related to vehicular emissions [10,11].