Improvements in the Process for the Preparation of Hexa- methylentetramin and its Chloral Bromal and Butyl-chloral Derivatives.
Year: 1897

page_text: Date of Application, 28th July, 1897-Accepted; 30th Oct., 1897
:
COMPLETE SPECIFICATION.
Improvements in the Process for the Preparation of Hexa-
methylentetramin and its Chloral Bromal and Butyl-chloral
Derivatives.
I, LEONHARD LEDERER of 761 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:—.
―
Formaldehyde and Ammonia unite as is known to form Hexamethylentetramin
giving off water. For the preparation of this substance one learns in previous
communications (Beilstein Handbook of Organic Chemistry 3rd Ed., 1.Vol.
P. 1167; Liebig, Annals of Chemistry Vol. 272 P. 271) that one adds Formaldehyde to
an aqueous solution of Ammonias and heats the mixture in a water bath. In these
experiments however secondary reactions always take place which influence the
amount, and purity of the hexamethylentetramin formed.
These disadvantages can be avoided, as I have found in direct contradiction to
Wohl (Reports of the German Chemical Society Vol. 19. P. 1842) according to
whose research (suggested by A. W. Hoffmann) an aqueous solution of hexamethylen-
tetramin is so thoroughly decomposed in distilling under diminished pressure, that
the distillation remainder has a neutral reaction and contains oxymethylene. This,
I say, can be prevented if the aqueous solution of Hexamethylentetramin, prepared
from Formaldehyde and aqueous ammonia, (instead of ammonia, one can use
carbonate of ammonium, solid or in solution) be evaporated in an air rarefied space
of about 500 m/m. The result of these experiments agrees with the theory.
Chloral and Bromal derivatives of Hexamethylentetramin are obtained if one
brings together Formaldehyde, Ammonia and Chloralhydrate or Bromal Hydrate or
Butyl-chloralhydrate.
Molecular masses (equal weights molecularly) of Formaldehyde and Ammonia (or
Carbonate of Ammonium) are evaporated in an air rarefied space at water bath
temperature.
The Hexamethylentetramin remains behind as a hard crystalline mass.
By once dissolving with alcohol it is freed from impurities resulting from the
aldehyde and in this way one obtain shiny white crystals which resist the action of

page_text: remains behind as a crystalline powder. By dissolving with chloroform, benzol or
other special solvents one can obtain it perfectly pure.
The evaporation of the reaction mixture can be avoided by adding to the Chloral-
condensation-product a neutral salt.
2nd. Instead of Ammonia one can use carbonate of ammonium.
To 1.5 pts. of 40% Formaldehyde solution one adds 0.7 pts. solid carbonate of
ammonium, and after thorough mixing, 1.1 pts. of chloral hydrate are added to the
clear solution. The reaction is quickly completed. The mass is left for a time by
itself with occasional stirring and lastly the separated crystals are collected upon a
filter.
The residue, Hexamethylentetramin chloral, on drying forms a white crystalline
powder free from impurities. By saturating the filtrate with a neutral salt one can
obtain further condensation products.
In a similar fashion one can prepare combinations of Bromal and Chloral with
Hexamethylentetramin-The Chloral-Bromal-and Butylchloral derivatives break
up easily into their components.
Even on simply warming their aqueous solutions they split up.
Acids and Alkalies decompose the compounds in the cold.
Having now particularly described and ascertained the nature of this said
invention and in what manner the same is to be performed I declare that what
I claim is
1. A Process for the production of Hexamethylentetramin consisting in heating
under diminished pressure aqueous solutions of Formaldehyde and Ammonia (or
carbonate of ammonium).
2. A Process of purifying the Hexamethylentetramin and obtaining crystals of
the same which withstand action of the air, by dissolving with alcohol.
3. A Process of preparing Chloral--Bromal-and Butylchloral derivatives of
Hexamethylentetramin consisting in bringing Formaldehyde, Ammonia (or carbonate
of ammonium) and Chloral hydrate, Bromal hydrate or Butylchloral hydrate into
reaction.
4. A Process of separating--chloral-bromal-and butylchloral derivatives of
Hexamethylentetramin from their solutions consisting in evaporating the solution of
these substances in rarefied air.
5. A process of separating Chloral-Bromal-and Butylchloral derivatives of
Hexamethylentetramin from their solutions, consisting in saturating the solution of
these substances with neutral salts.
Dated this 27th day of July 1897