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 It might be outdated or ideologically biased.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 ?
Higher soil phosphatase activity was observed with 100% RDN though green manure ([T.sub.5]) (38.8 [micro]g of p- nitrophenol released [g.sup.-1] of soil 24 [h.sup.-1] in 2012 and 38.6 in 2013) and it was comparable with TRRI practice ([T.sub.13]) (38.6 and 38.4) and 25% RDN through each organic manure ([T.sub.12]) (37.4 and 37.2) during both the years of study.
All results are expressed in U/ml which is defined as 1 nmol of 4- nitrophenol formed per minute.
Exposure of the general population to nitrophenol isomers is mainly through ambient air and drinking water.
Zablotowicz, "Chlorophenol and nitrophenol metabolism by Sphingomonas sp UG30," Journal of Industrial Microbiology and Biotechnology, vol.
TEHRAN (FNA)- Iranian researchers from Tehran University of Medical Sciences succeeded in the enzyme degradation of nitrophenol pollutants by using porous silica beads.
Gan, "Electrochemical oxidation process combined with UV photolysis for the mineralization of nitrophenol in saline wastewater," Separation and Purification Technology, vol.
By the electroreduction [3] of nitrophenol isomer using stationary and rotating Cu electrodes and Ti(S04)2 as additional agent, aminophenols were obtained in good yield.
Degradation of nitrophenol under sonication can lead to defacement of ester hydrolysis kinetics and this issue has been discussed in detail in our previous paper [9].
Activity against [beta]-N acetylglucosamide and G mannopyranoside, using para nitrophenol (pNP) conjugates showed that chlamydia expressed high levels of [beta]-N acetylglucosaminidase and G mannosidase.
Nonspecific esterase activity was measured as the average change in optical density per minute at 400 nm and then converted to units (micromoles of 4-NPC hydrolyzed per minute) using the extinction coefficient for nitrophenol of 19,800 [M.sup.-1] [cm.sup.-1] at pH 8.5 and 405 nm (Gjellesvik et al., 1992).
The activity of this enzyme can be assayed using o-nitrophenyl-[Beta]-D-galactopyranoside, which is a substrate that is hydrolyzed by [Beta]-galactosidase to nitrophenol. Nitrophenol can be confirmed either visually on the basis of a yellow color or by optical spectrometry at its absorption peak of 420 nm.