AMIDOSULPHONIC ACID. 221 



that it was Berglund who first recognised that the product of the 

 interaction of sulphur trioxide and ammonia is not amidosulphonate 

 but iniidosulphonate, it seems wise to accept his assertion as one well 

 founded, that occasionally ;t very little real amidosulphonate is also 

 formed. 



2. Ammonium iniidosulphonate readily hydrolyses into the 

 amidosulphonate (Berglund, 1876). The iniidosulphonate is obtain- 

 able from chlorosulphonic acid, from pyrosulphurvl chloride and 

 sulphuryl chloride (after the action of water), as well as from sulphur 

 trioxide, and ammonia. 



3. Sulphamide, which is a product of the interaction of sulphuryl 

 chloride and ammonia (Regnault ; W. Traube), is decomposed by 

 alkalis into amidosulphonate and ammonia (Traube, 1893). 



4. By acting on acetonitrile with fuming sulphuric acid, a 

 derivative of amidosulphonic acid is obtained, acetyl acetamidine- 

 sulphonic acid, which hydrolyses, with extreme readiness, into 

 diacetamide and amidosulphonic acid (Eitner, 18i)i J ). 



In the above four cases, amidosulphonic acid comes out as a 

 sulphuric derivative ; in those which follow, it comes from sulphur 

 dioxide. In the first of them appear again imidosulphonates. 



5. Nitrites, fully sulphonated by sulphur dioxide, become nitrilo- 

 sulphonates, which very easily hydrolyse into imidosulphonates, and 

 these, again, can be hydrolysed into amidosulphonates (Berglund, 

 1876). The hydrolysis of potassium iniidosulphonate was studied by 

 Fremy, and by Claus and Koch, long before Berglund, but without 

 amidosulphonic acid being discovered by them. Its production was 

 overlooked, no doubt, through the great solubility of its potassium 

 salt, and through its ability to be destroyed by further hydrolysis. 



6. Oxyamidosul phonic acid is produced by the hydrolysis of 

 oximidosulphonic acid, which is formed by the sulphonation of a 



