ACTION OF SULPHURIC ACID UPON THE AMIDES AND NITRILES. 
475 
Action of Sulphuric Acid upon Aniline. 
In order to prepare disiilphanilic acid, two parts of strong sulphuric acid were mixed 
with one part of aniline, when heat was freely evolved, sulphate of aniline being 
thrown down at the same time. On further application of heat the salt redissolved, 
and as the liquid reached the boiling-point it became very dark in colour, sulphurous 
acid being freely evolved. 
In our first experiment the mixture was kept in full ebullition for ten minutes, and 
then poured into water after it had partially cooled. A confusedly crystalline mass 
was produced which was well washed with cold water (in which it is not very soluble), 
and afterwards recrystallized from hot water. 
Sulphanilate of Silver. 
A portion of this acid was digested with carbonate of silver. The crystalline silver- 
salt, obtained by evaporating the solution at a low temperature, was dried at 120'" 
and ignited. 
0‘3524 grm. gave 0 1360 grin, of reduced silver, which coincides with the theoretical 
percentage of sulphanilate of silver, 
Ci2 (Hg Ag) N S 2 Og. 
Theory. Experiment. 
Silver ... 38-57 '38-58 
Sulphanilate of Barium. 
A barium-salt, prepared in the usual way and submitted to analysis by precipitation 
by sulphuric acid, gave perfectly analogous results. 
0-4250 grm., at 160°, gave 0-2060 grm. sulphate of barium, 
corresponding to the formula 
C ,2 (IlgBa) N S 2 Og. 
Theory. Experiment. 
Barium . . . 28-48 28-40 
These experiments proved that the acid produced was nothing but M. Gerhardt’s 
well-known sulphanilic acid, the reaction not having gone far enough for the pro- 
duction of the second acid. The treatment with sulphuric acid was therefore 
resumed. Finely powdered and dry sulphanilic acid, mixed with strong fuming acid 
to the consistency of a thin paste, was heated in an air-bath to a temperature just 
approaching that at which sulphurous acid is generated, to 160° and 1/0° C. This 
digestion was continued until a portion taken on a glass rod did not solidify on cool- 
ing, or give any solid matter when dissolved in a small quantity of water, which 
happened after the lapse of seven hours, when the mass had the consistency of treacle. 
MDCCCLVI. 3 R 
