Res. Chem. Intermed.
, Vol. 34, No. 1, pp. 53–65 (2008)
Also available online - www.brill.nl/rci
Reactions of reducing radicals with 2- and 3-nitroanilines
in aqueous solutions: a pulse radiolysis study
and K. KISHORE
Water and Steam Chemistry Division, Kalpakkam, Tamil Nadu-603102, India
Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Trombay,
Mumbai 400 085, India
Received 11 July 2007; accepted 24 August 2007
Abstract—Reactions of 2- and 3-nitroanilines (2- and 3-NA) with e
, H-atoms and one-electron
reductants have been studied using pulse radiolysis in aqueous solutions. Reactions of e
to be quite fast with both 2-NA and 3-NA resulting in their corresponding semi-reduced species which
are reducing in nature. Reduction potentials for 2-NA/2-NA
have been estimated to be approx.
−0.56 V vs. NHE and that for 3-NA/3-NA
was found to be between −0.185 V and −0.45 V
vs. NHE. Semi-reduced 2-NA has main absorption peak at 300 nm with a shoulder in the 350 nm
region and a broad weak band in the 470–500 nm region, whereas semi-reduced 3-NA possesses
an absorption peak at 520 nm. Reducing radicals such as (CH
OH and CO
2-NA, producing semi-reduced species, whereas reactions of these radicals with 3-NA produced their
corresponding radical-adduct species.
Keywords: 2-nitroaniline; 3-nitroaniline; pulse radiolysis; absorption spectra.
Aromatic amines are used both as diazo and coupling components in the synthe-
sis of azo dyes. Nitroanilines are also used as intermediates in pigments, phar-
maceuticals, antifoggants and pesticides like carbendazine. Azo-dyestuffs release
carcinogenic aromatic amines on reductive splitting and are toxicologically relevant
to humans  as intestinal bacteria or azo-reductase present in the human liver or
other organs can also split the dye in a reductive medium . Compounds like ben-
zofuroxanes (known for their biochemical and pharmacological properties) produce
2-nitroaniline on reduction, which can oxidize oxyhemoglobin (HbO
) in blood to
) . Different nitroanilines are also detected in waste-
water released from TNT production facilities and in open-detonation grounds .
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