Chemistry Reference
In-Depth Information
BENZENE DERIVATIVES
N
ITROBENZENE
AND
A
NILINE
Uses
Virtually all of the nitrobenzene made is converted to aniline.
The most important use of aniline is for the preparation
of 4,4
-diaminodiphenyl methane (commonly called
methylenedianiline or MDA), an intermediate to one of the
main ingredients used to make polyurethane foams and
rubber. Aniline is also used to make other rubber
chemicals, textile fiber intermediates, dyes, and
pharmaceuticals.
′
Manufacture
NO
2
NH
2
catalyst
H
2
SO
4
+
+
NHO
3
(nitric acid)
H
2
nitrobenzene
aniline
Suppliers
BASF, Bayer, DuPont, Huntsman, First Chemical.
Up to three of the hydrogens on a benzene ring can be replaced with a nitro
(
NO
2
) group by reaction of nitric acid in sulfuric acid. When two hydrogens
are replaced by nitro in this manner (dinitration), one isomer, the
meta
- or
1,3-, predominates. When three hydrogens are replaced (trinitration), the
predominant isomer is the 1,3,5-isomer;
meta
-dinitrobenzene is made by
this method as a starting material for
meta
-phenylenediamine, one of the
components in the manufacture of a heat-resistant nylon sold in the U.S.
as “Nomex” by DuPont.
Obviously, polynitro- or polyaminobenzenes other than the
meta
-config-
uration may be desirable for one reason or another. This is where the skill
and training of organic chemists are required because they have learned to
be able to know and use the rules of chemistry to manipulate the shape and
composition of carbon-containing molecules.
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