ACTION OF SULPHURIC ACID UPON THE AMIDES AND NITRILES. 
461 
Examination of the mother-liquor of Disulphometholate of Ammonium. 
Sulphacetate of Ammonium and Sulphacetate of Barium. 
It has been already noticed that another salt is present in the mother-liquid 
obtained during the purification of disulphometholate of ammonium. To procure this 
substance in a state of purity the mother-liquid was concentrated, and the crystals 
of the disulphometholate removed from the thick syrup as completely as possible. 
After a moderate addition of cold water the liquid was mixed with an excess of 
chloride of barium, and the whole allowed to stand for five or six minutes, when it 
was filtered, and the filtrate set apart for twenty-four hours. At the expiration of 
this time a copious granular precipitate had formed which was well washed with 
cold water and then recrystallized from boiling water, in which, when once deposited, 
it proved to be very little soluble. 
This substance differs both in its crystalline form and in its reactions from the 
disulphometholate. When strongly heated, it turns black and burns away like tinder. 
The residuary mass, moistened with hydrochloric acid, evolves according to the time 
of ignition, hydrosulphuric and sulphurous acid. 
By analysis, 0*6266 grm., dried at 220°, gave 0'5287 of sulphate of barium. 
The percentage of barium resulting from this experiment agrees well with the 
amount required by the formula of sulphacetate of barium. We append the theo- 
retical and experimental percentages ; — 
Formula. Barium calculated. Barium found. 
C 4 (H 2 Ba^) S 2 Oio 49-81 49-60 
'■ Y- ; * 
Sulphacetate of barium. 
The quantity of sulphacetate of ammonium produced, mainly depends upon the 
degree of heat maintained during the reaction of sulphuric acid upon acetamide or 
acetonitrile. If the mixture be made gradually and cooled after each addition of 
acid, the elimination of carbonic acid may be entirely prevented, and the chief pro- 
duct is then sulphacetic acid. On the other hand, if the heat be urged as far as is 
practicable, disulphometholic acid takes the place of the sulphacetic, carbonic acid 
being evolved at the same time. 
Two phases may therefore be traced in the reaetion. In the first, nascent acetic 
acid simply combines with the elements of two equivalents of anhydrous sulphuric 
acid. In the second phase the acetic molecule undergoes a more thorough trans- 
formation, splitting, as it does, into carbonic acid and marsh-gas, the latter of which 
combines with the elements of four equivalents of anhydrous sulphuric acid. 
The new acid may also be regarded as sulphacetic acid, which, losing carbonic acid, 
has assimilated an equal number of equivalents of anhydrous sulphuric acid. 
The two stages in the action of sulphuric acid on acetonitrile may be represented 
by the following equations : — 
3 p 2 
