urbaf2

NITRO DERIVATIVES OF HIGHER BENZENE HOMOLOGUES^403

which they separated into two isomers - 3,4,5- (or 4,5,6-) and 3,4,6- (or

3.5,6-):

m. p. 115°C m. p. 72°C

Later these observations were confirmed by Marqueyrol and Loriette [9]. From

100 parts of o- xylene, 130-135 parts of trinitro derivatives are obtained.

To separate the isomers use is made of their different solubility in 75%

sulphuric acid. The mixture of isomers is dissolved in the acid at 120-130°C, and

then cooled; only the 3,4,5-isomer crystallizes then. The 3,4,6-isomer left in the acid

can be precipitated from the solution by adding water. The 3,4,5-isomer can be

purified by crystallization from 75% sulphuric acid, the 3,4,6-isomer by

crystallization from alcohol.

Both isomers react with sodium sulphite to form the corresponding sulpho

derivatives :

Only one trinitro-p-xylene exists, viz. 2,3,5- or 3,5,6-trinitro-p-xylene :

m. p. 139-140°C

It was first obtained by Noelting and Geissmamr [18] in a yield of 150 parts Per

110 parts of p- xylene.

With an alcoholic solution of ammonia, trinitro-p-xylene gives dinitroxylidine: