468 
BRISTOL PHARMACEUTICAL ASSOCIATION. 
Mr. Boucher then read a paper upon “ Hydrate of Chloral,” of which the following 
is an abstract:— 
After reviewing the medical opinions and aspect of chloral, Mr. Boucher stated the 
term chloral,* a contraction of chlorine and alcohol, the substances used in its prepara¬ 
tion was originally given by Baron Liebig, the discoverer of it in 1832, who, as well as Du¬ 
mas, prepared it and minutely investigated its properties. At a much earlier date, Sclieele 
and other chemists diligently studied the action of chlorine on alcohol, but do not appear 
to have actually separated this substance. Nevertheless, as chloral, till within a few 
months of the present time has continued a laboratory preparation of no pharmaceutical 
value whatever, to Dr. Otto Liebreich, Chemical Assistant in the Pathological Institute 
of Berlin, in fairness belongs the credit realized by the addition of this medicine to our 
list of sedatives and anaesthetics. 
In the preparation of chloral, anhydrous alcohol is saturated with dry chlorine gas, 
when a very beautiful and very simple substitution of elements results, expressed by the 
following equation:— 
C 4 H 6 0 2 + Cl 8 zz C 4 Cl 3 0, HO + 5 H Cl. 
Alcohol. Chloral. 
This, however scarcely represents the views adopted by chemists regarding it; the 
alcohol is supposed to pass into the intermediate state of aidehyd, by having two atoms of 
its hydrogen abstracted:— 
C 4 H, 0, HO + 2 Cl zz C 4 H, 0, HO + 2 H Cl. 
Alcohol. Aidehyd. 
A new and entire rearrangement of elements now takes place, the aidehyd exchanging 
its three atoms of hydrogen for three of chlorine, to form acechloryl, the compound radical 
of chloral:— 
C 4 H 3 0, HO 4- 6 Cl zz C 4 Cl 3 | 0 + H0 + 3HC1. 
Aidehyd. Acechloryl. 
\ ___ / 
Chloral. 
In carrying out this process, the author followed the instructions of Liebig. Anhy¬ 
drous alcohol is placed in a dry receiver, through one opening of which dips into the 
liquid the long limb of a bent tube from a Woulff’s bottle. To another opening in the 
receiver is attached a long glass tube drawn out to a fine point, the object of this being 
to condense any spirit evaporated by the heat necessary to be applied during the process. 
The Woulffs bottle is partially filled w r ith pure sulphuric acid, and connected with a 
large vessel of binoxide of manganese and hydrochloric acid. The chlorine generated 
is passed in a full stream for many hours, first through the acid, and from thence to the 
alcohol. At the commencement of the process the alcohol becomes sufficiently heated 
by the action taking place, but afterwards the application of a little heat will be neces¬ 
sary, not only to favour the action but to drive off an abundance of hydrochloric acid 
formed during the process. When free chlorine is given off, this part of the process is 
stopped, the impure chloral transferred to a separatory funnel and mixed with thrice its 
bulk of sulphuric acid. A good deal of heat and excitement takes place, the result being 
a layer of thin yellowish-looking oily liquid floating on the surface of the more coloured 
acid beneath; this is drawn off, and together with a further quantity obtained from the 
acid by distillation, exposed to a little heat, rectified from a small quantity of fresh sul¬ 
phuric acid, and again from slaked lime, the product being pure chloral. 
Chloral is distinguished by its peculiar, very penetrating odour, caustic, disagreeable 
taste, by its colourless oily appearance, inaction on nitrate of silver, and by its solidify¬ 
ing in presence of a small quantity of w r ater; it is very soluble in water, alcohol, and 
ether, and forming with dilute alkalis formiate of the base and chloroform. 
C 4 H Cl 3 0, HO + K OzzK 0, C 2 H 0 3 + C 2 H Cl 3 . 
The hydrate of chloral crystallizes in two forms, one in needles containing one atom 
of water, the other in rhomboids with two; specimens of each were exhibited. The au¬ 
thor by no means recommended this process for the preparation of chloral, but considered 
* Viewed by some writers as chloraldehyd. 
