56 Dr. R. Hoffmann on Monochloracetic Acid. 
it would thus contain 2(S? 0+) in copulated combination with 
the radical C2 H?, which can replace two equivalents of hydro- 
gen. The formation of methionic acid might be explained as 
arising from the oxidation of a part of the carbon. In fact, 
Strecker observed the occurrence of carbonic acid as well as an 
abundant evolution of sulphuric acid. 
Some time after the preceding investigation was completed, 
Strecker recognized methionic in disulphometholic acid, the acid 
obtained by Buckton and Hofmann from the action of sulphuric 
acid on acetonitrile. And by preparing some of the acid accord- 
ing to the methods described by these chemists, he was able to 
establish its identity with methionic acid, not only by ocular 
demonstration, but by analysis. 
Reinhold Hoffmann * has examined the monochloracetic 
acid, the existence of which, although pointed out by Dumas, 
and afterwards by Leblanc, has never been satisfactorily esta- 
blished. It is obtained by bringing chlorine into contact with 
monohydrated acetic acid ; its formation begins probably even in 
the dark, but takes place best in sunlight, if the chlorine be not 
in too great excess. It is always accompanied by the formation 
of a small quantity of a higher chlorinated acetic acid, and it is 
probable that the formation of monochloracetie acid is the first 
step, and that from this the higher chlorinated acid is formed. 
Monochloracetie acid, C4 H® C] O?, is a well-characterized 
acid, and forms crystalline salts. Itis, when pure, a crystalline 
solid at a temperature of 62°, and boils at 183°. In its physical 
properties it, is much nearer trichloracetic acid than acetic 
acid. Its relation to alkalies exhibits considerable differences 
from its type; just as acetic acid when treated with alkalies 
yields marsh-gas, 
C+ H4 01+2K0, HO=C? H*+2KO CO?+2HO; 
Acetic acid. Potash. Marsh-gas. Carbonate 
of potash. 
aud trichloracetic acid gives chloroform, 
C4 H Cl? 04+ 2KO HO=C? H Cl8+ 2K0O CO?+2HO; 
Trichloracetie Chloroform. 
acid. 
monochloracetic acid ought to give chloride of methyle, 
C+ H3 Cl 04+2KO HO=C? H8 Cl+ 2KO CO?+2HO; 
Monochloracetic Chloride 
acid. of methyle. 
but chloride of methyle is not formed at all in this reaction ; 
indeed the decomposition seems to be quite different, and is re- 
served by Hoffmann for further investigation. 
Monochloracetic acid is reduced by the action of potassium 
* Liebig’s Annalen, April 1857. 
