of Edinburgh, Session 1870-71. 
419 
5. On the Formation and Decomposition of some Chlorinated 
Acids. By J. Y. Buchanan. 
1. On the Rate of the Action of a Large Excess of Water on Mono- 
chloracetic Acid at 100° C. — When monochloracetic acid is heated 
with water, double decomposition takes place, glycollic and hydro- 
chloric acids being formed ; and conversely, when glycollic acid is 
heated with hydrochloric acid, it is converted into monochloracetic 
acid and water. A similar reaction takes place with the two mono- 
chloropropionic and corresponding lactic acids, and probably with 
all their homologues. 
The task which I have set myself is to study these reactions, in 
so far as they are dependent upon temperature, duration of reaction, 
and relative mass of reacting substances. In the present commu- 
nication, I give the results of experimenting upon monochloracetic 
acid with a very large, practically infinite, excess of water at 
100° O. 
The monochloracetic acid was purchased from Dr Marquart, of 
Bonn, and rectified. What passed between 180° and 190° was 
used for the following experiments : — A watery solution of it was 
made which contained in a litre 32*4 grms., and showed a specific 
gravity = 1*01 24, whence the chloracetic acid and the water were 
mixed in the proportion of one molecule of the former to 164 
molecules of the latter. 
As the increase of the acidity of the solution is the measure of 
the decomposition which takes place, it is easily determined by 
titration. For this purpose a solution of caustic soda was gene- 
rally employed, although in the earliest experiments baryta water 
was made use of.* The saturating power of these reagents was 
* Berthelot (Ann. de Chim. et de Pliys. [3], lxv., 401) made use only 
of baryta, his objections to potash and soda being that they always contain 
carbonate, and that their salts with organic acids always have a more or less 
alkaline reaction. The first of these objections may be got rid of by keeping 
the solution, freed from C0 2 in the first instance by lime water, in a number 
of small bottles filled full up to their tightly fitting corks. The second I have 
found not to apply to the bodies here in question. There is no doubt, how- 
ever, that baryta solution does present considerable advantages in the greater 
ease with which it can be procured in a state of absolute purity ; and that 
any carbonic acid which it may absorb is at once eliminated, thereby, how- 
