ACTION OF SULPHURIC ACID UPON THE AMIDES AND NITRILES. 
455 
Action of Sulphuric Acid on Acetonitrile. 
This body, when mixed with its own volume of fuming sulphuric acid, gives rise 
to a very energetic reaction, a considerable amount of heat being evolved, which 
causes much of the nitrile to volatilize and thus escape decomposition. In order to 
avoid this, the operation is best conducted in a retort surrounded with cold water, 
when a perfect mixture can be effected, scarcely a change of colour becoming per- 
ceptible. On application of heat the mixture powerfully intumesces with copious 
evolution of a gas which on examination over mercury proves to be carbonic acid, 
without a trace of carbonic oxide; at the same time strong acetic acid passes into 
the receiver. If the temperature be kept up by the gas-flame until the effervescence 
almost entirely ceases, the mass when cold forms a brown, tough and transparent 
solid, readily soluble in water and in alcohol. The aqueous solution, boiled with an 
excess of carbonate of barium, is then passed through a hot-water filter, when a mag- 
nificent salt is deposited, in the form of brilliant colourless rectangular plates which, 
when gathered in mass, exhibit a nacreous lustre. This salt is remarkably stable. It 
loses no weight at 100°C., but gives off water of crystallization somewhat below 150°. 
At a temperature of 220° the substance still remains unaltered, but when heated be- 
yond this point, it commences to turn yellow, rlisengages water, sulphurous acid and 
carbonic oxide, whilst sulphur sublimes. When strongly heated it becomes incan- 
descent, leaving a residue of sulphate and sulphite of barium. The new salt may be 
crystallized unchanged from hydrochloric acid, and may be boiled for hours with con- 
centrated nitric acid, without formation of sulphate of barium. It is quite insoluble 
in alcohol. 
Action of Sulphuric Acid upon Acetamide. 
As acetamide differs from acetonitrile only in containing two additional equivalents 
of water, this compound, when heated with fuming sulphuric acid, undergoes a per- 
fectly analogous transformation. 
From the comparative facility of its preparation, acetamide offers peculiar advan- 
tages for procuring the new substance in large quantity. The chief difficulty which 
presents itself consists in operating with the right proportions of acid and amide. 
Distillation of equal volumes of dry acetamide and ordinary Nordhausen acid, for 
instance, gives scarcely a trace of anything but acetic acid and sulphate of ammonia. 
The most efficient proportions we found to be two volumes of amide to three volumes 
of acid. The distillation should be pushed very far, in fact until the product of 
distillation is accompanied by sulphurous acid. The solution of the solid residue 
may at once be saturated with carbonate of barium ; it will be found, however, more 
economical to treat the liquid with finely-powdered Carrara marble until the free 
acid be neutralized, and to reserve the pure carbonate of barium, which is so diffi- 
cult to wash thoroughly, merely for decomposing the sulphate of ammonium towards 
the end of the process. The liquid must be boiled with excess of the carbonate until 
