4-NITRO-5-METHYL-2-SULPHOBENZOIC ACID 
189 
is cliaracteristically different from that of the symmetrical chlor- 
ide. In making the ammonia derivative in practice, the ammonia 
was diluted with three parts of water to lessen the action. If 
the ammonia is evaporated off and the remaining liquid is con- 
centrated and cooled, crystals form in nodules. These crystals 
are not as sharply defined as those of the corresponding am- 
monium salt of the imide; the nodules appear to be made up 
of compact masses of radiating crystals which branch continual- 
ly into fanlike shapes. When these nodules are crushed, it is 
impossible to find any characteristic crystalline form. Recrystal- 
lized from alcohol, however, the crystals were not bunched but 
seemed to be laminated plates almost cubical in form, but with 
no smooth surfaces. The yield of the product is good. In no 
case was there any indication of the ammonium salt of the imide. 
The salt is more soluble than the ammonium salt of the imide. 
Its melting point is 310-311°, with decomposition. 
Since this salt is not the ammonium salt of the imide, it must 
be either the diamine (I), or the ammonium salt of the cyan 
acid (II). 
CHs- 
I NO, 
CONH, 
SO,NH, 
CHs 
II NO, 
C=N 
SO 3 NH 4 
The cyan formula for bodies of this type is derived from the 
work of Hoogewerff and Van Dorp^^, on the action of ammonia on 
phthalic chloride. They give the reaction thus — 
C.R, 
c=cu 
^o -f- NHs 
0=0 
C=NH 
•> ^O 
0=0 
iso imide 
0=NH 0=N 
C6H4<( )>0 > C6H4<( 
0=0 COOH 
iso imide cyan acid 
i^Rec. Trav. Chim., 11, 84; 12, 12, 1892. 
