(^66) CHEMISTRY AND TECHNOLOGY OF EXPLOSIVES
for example, in nitrating toluene with a mixture of nitric and sulphuric acids they
obtained a product containing 60% of p- nitrotoluene, while in nitration with
nitric acid alone the para- isomer content was 66%.
Baker and his co-workers [60,61] investigated the influence of the sulphuric
acid concentration in nitrating mixtures on the meta- nitro derivatives of the fol-
lowing compounds: benzaldehyde, benzophenone and ethyl benzoate. The con-
tent of a meta- nitro derivative increases with the increase in acidity of the solution.
For example, in nitration with a nitrating mixture contaming 80% sulphuric acid
the yield of m- nitrobenzaldehyde is 83.9%. When nitrated with a mixture containing
TABLE 5
NITRATION OF ANILINE AND ANILIDES
Nitrated compound Composition of the product
% ortho- % meta- % para-
With nitric acid
Aniline nitrate 4 56
Acetanilide 42
40
58
Benzanilide 40 60
Formanilide 35 - 65
Chloroacetanilide 27 - 73
Oxanilide 15 - 85
12 - 88
With a solution of 94% nitric acid in the concentrated sulphuric acid
Aniline^1
Acetanilide^8
Benzanilide^7
Formanilide^6
ChloroacetaniIide^4
Oxanilide 2
2
49 50
- 92
- 93
- 94
- 96
- 98
- 98
With a solution of 80% nitric acid in anhydrous acetic acid
Aniline^36 - 64
Acetanilide 30 -^70
Benzanilide 28 - 72
Formanilide 26 - 74
Chloroacetanilide 25 - 75
Oxanilide 21 - 79
16 - 84
oleum (7.3% of free SO 3 ), benzaldehyde gives m- nitrobenzaldehyde in 90.8%
yield. According to Baker, under the influence of sulphuric acid, the oxonium ion
is formed, e.g.:
(29)
The oxonium group directs mostly to the meta position.