urbaf2

NITRO DERIVATIVES OF BENZENE 239

V

The proportion of the compounds is: III-80%, IV-13%, V-7%.

As m- dinitrobenzene reacts with sodium sulphite with more difficulty, this

reaction is now used for removing the o- and p- isomers from commercial dinitro-

benzene (pp. 246-248).

TABLE 36 ADDITION PRODUCTS OF DINITROBENZENE ISOMERS

Second component

Acenaphthene Phenanthrene Naphthalene Aniline o- Phenylenediamine

composition of the products

none none none none none

m- Phenylenediamine none

p- Phenylenediamine α -Naphthylamine β -Naphthylamine

none none

o- Dinitrobenzene

m.p. °C

m- Dinitrobenzene p- Dinitrobenzene

composition of the

m.p. composition °C of the products products

1:1 none 1:1 1:1 3:2 (unstable) 1:2 (unstable) none none 1:1

72.3

50.5
41.5
58.3

1:3 81.5 1:l ca. 117 none - none -

36.2

63.8

1:2

1:1 1:1 1:1

m.p. °C

114 81 91

m- Dinitrobenzene is used for the identification of some ketosteroids (andro-

sterone, estrone, pregnandione, cortisone etc.). A blue colour develops in the presence

of potassium hydroxide. This is a modification of the Janovsky reaction suggested

for this particular purpose by Zimmermann [17] (p. 207).

m- Dinitrobenzene reacts with liquid ammonia to give a purple solution

containing an addition anion [68].

Dinitrobenzenes form addition products with hydrocarbons with condensed

rings, as well as with aromatic amines, p- nitrobenzene entering the reactions the

most readily, and o- dinitrobenzene - the least so. The addition products formed

by dinitrobenzenes with various compounds have been extensively studied by

Kremann and co-workers [18], Szperl and co-workers [19-20b], Giua [15].
Jefremov [9,11], Hrynakowski and KapuScinski [12].

Some of the addition products are shown in Table 36.