MANUFACTURE OF ACETONE. 
55 
acetone. This takes place, for example, with the acetates of potassa^ 
soda, and baryta. Where the oxide cannot retain carbonic acid at 
a red heat, as in the case of acetates of magnesia, zinc or 
manganese, the acetone is accompanied by carbonic acid. If the 
oxide be easily reducible, as in the acetates of copper, silver, and 
mercury, there are given off hydrated acetic acid, carbonic oxide, 
carbonic acid, water, and acetone, and there is left a mixture of the 
metal with carbon in a minute state of division. 
In Thomson's Inorganic Chemistry, vol. ii., p. 23, edit. 1831, 
there is a table of the relative quantity of products obtained from the 
decomposition of several metallic acetates. The following extract 
shows the quantity of pyro-acetic spirit obtained : — 
Acetate of silver 0.00 
" copper 0.17 
" nickel 0.20 
" iron 0.24 
'< lead ------- 0.55 
" zinc ------- 0.69 
" manganese 0.94 
The acetates of potash, soda, lime, and baryta yield a much larger 
proportion of pyro-acetic spirit than any of the metallic acetates, and 
are therefore generally employed for this purpose, more especially 
the acetate of lime. It would appear that the acetates of silver and 
of baryta stand at the two extreme points of the list of acetates in 
respect to the production of pyro-acetic spirit; the former yielding 
only a concentrated acetic acid with not a trace of spirit, whilst the 
latter yields a liquid product almost entirely spirituous, with scarcely 
a trace of acid. The acetate of copper also yields but a small pro- 
portion of pyro-acetic spirit ; hence its employment, as we shall sub- 
sequently notice, in the preparation of aromatic vinegar. 
Dumas submitted to dry distillation 100 parts of acetate of baryta, 
composed of 
Baryta ------ 56.0 
Acetic acid 37.4 
Water 6.6 
100.0 
and capable, therefore, of yielding 21.5 per cent, of pyro-acetic 
