Improvements in the Process for Preparing the Halogen Derivatives of Aceton.
Year: 1897

page_text: Date of Application, 28th July, 1897-Accepted, 18th Sept.,
1897
COMPLETE SPECIFICATION.
Improvements in the Process for Preparing the Halogen Derivatives
of Aceton.
I, LEONHARD LEDERER of 76' Gabelsbergerstrasse, Munich, Germany, Doctor of
Science, do hereby declare the nature of this invention and in what manner the
same is to be performed to be particularly described and ascertained in and by the
following statement :-
The halogens act very easily upon acetondicarbonic acid. In instance, Bromine
added to an aqueous solution of acetonedicarbonic acid is immediately taken up
and discolored.
An aqueous solution of aceton-dicarbonic-acid decomposed with iodin takes up
rapidly the colour of an alcoholic iodin solution without any visible reaction.
If however, this solution decomposed with iodin, be gently warmed, reaction takes
place with the evolution of carbonic acid gas. The action of the existing hydrogen-
iodide which causes secondary reactions to take place, renders hardly possible to
obtain the reaction products. This however can easily be done if one adds to the
reaction mass a substance, which has the property of combining with hydrogen-
iodide and thus removing its disturbing influence. Iodic acid serves excellently
for this purpose.
By this means it is possible to use the iodin to the utmost extent.
DESCRIPTION OF THE PROCESS.
To 10 pts. of acetone-dicarbonic acid dissolved in 10 times its mass of water are
added 20 pts. of iodin and as the mixture is being constantly stirred 9 pts. of
iodic acid are gradually added.. The reaction, which takes place rapidly, is
accompanied by a lively evolution of carbonic acid gas. To follow the sequence
of the reaction it is advisable to cool gently, because at a raised temperature, the
periodaceton is easily decomposed by precipitation of iodin.
The addition of iodic acid must begin when the light yellow reaction mass
takes on an orange colour. Directly all the iodin has been used up, the reaction
is finished. The resulting per-iod-aceton is then at once separated from this liquid,
thoroughly washed, and dried at ordinary temperature. It forms a light yellow
crystalline powder, which becomes dark on heating up to 60°. If it has pre-
viously been freed from water it melts at 78° C. On boiling with water it sets
free iodin and becomes penta-and eventually tetra-iod aceton.
Also if not kept dry, under certain circumstances at ordinary temperature it.
undergoes decomposition, which is sometimes associated with so much heat pro-
duction that iodin is set free in the form of vapour. Alcohol, ether, in fact most
of the organic solvents set free iodin from per iod-aceton. With dilute Soda-lie
it forms iodoform in the cold.
The action of iodin upon aceton-dicarbonic acid can be so regulated by definite
diminutions of the quantity of iodin added, as to result in lower stages of iodin
combination with aceton.
With regard to its behaviour towards alcohol and ether the penta-iod-derivative
is in close relation with the periodoceton. On the addition of dilute Soda-lie it is

page_text: transformed in iodoform even in the cold, but not with Soda solution. If one
warms it with the latter it is converted (as in the case of tetra-iod-acetone) in
di-iod-acetone.
Bromine and Chlorine act in a similar way with regard to acetone-dicarbonic
acid. In consequence of the liability of the setting free of halogen hydrogen
acids, it is not necessary to take any special precautions in observing the progress
of the reaction. In some cases it is advisable to add carbonate of calcium or
similar substances to combine with the free acids, or to use in the experiments
simply dilute solutions of the acetone dicarbonic acid.
Having now particularly described and ascertained the nature of this said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. A Process for preparing iodin derivatives of acetone by making react iodin
in ordinary forms or in the nascent state with acetone dicarbonic acid in the
presence of a substance which either combines with or splits up hydrogen iodide.
2. A Process for preparing Bromine derivatives of aceton by making react
Bromine with acetone dicarbonic acid with or without the presence of a substance
which combines with free acid.
3. A. Process for preparing Chlorine derivatives of aceton by making react
Chlorine with acetone dicarbonic acid with or without the presence of a substance
which combines with free acid.
Dated this 27th day of July 1897