A Process for the Preparation of Guanidine Salts.
Year: 1897

page_text: Date of Application, 10th Dec., 1897
Complete Specification left, 9th Sept., 1898-Accepted, 29th Oct., 1898
A Process for the Preparation of Guanidine Salts.
We, Dr. ALWIN GOLDBERG, School-teacher, of 3, Inselstrasse, Chemnitz, Dr.
WILHELM SIEPERMANN, of 259, Hauptstrasse, Kalk, and Dr. HUGO FLEMMING, of 165,
Hauptstrasse, Kalk, all in the German Empire, do hereby declare the nature of this
invention to be as follows :-
This invention relates to a process for the preparation of guanidine salts.
By the ordinary processes for the preparation of guanidine by fusing
sulphocyanide of ammonia, the former can only be obtained as the sulphocyanide
and the yield is unsatisfactory; furthermore the decomposition takes place very
slowly.
Now we have found by experiment that by mixing oxides or salts of the heavy
metals with the ammonium sulphocyanide and heating the mixture in au
atmosphere of ammonia, guanidine sulphocyanide is obtained in larger quantities
and in a shorter time than usual and furthermore that the guanidine sulphocyanide,
when further heated with an equivalent quantity of a salt of a heavy metal in an
ammoniacal atmosphere, is further reacted upon, the guanidine uniting with the
acid of the metallic salt and more guanidine salt being formed from the ammonium
sulphocyanide thus reformed. The added metal salts are converted into metallic
sulphides. Guanidine sulphocyanide can also be obtained by heating sulpho-
cyanides of the heavy metals in an ammoniacal atmosphere. The various operations
can also be performed under pressure. By working with digesters the double
salts of ammonia can be employed in lieu of the sulphocyanide of the heavy metal
and ammonia.
As the above mentioned mixtures fuse together when heated, it is advantageous
to add a neutral porous substance, for instance, powdered charcoal, whereby the
ammonia can more easily penetrate the mass and the reaction is considerably
accelerated.
I. Preparation of guanidine sulphocyanide by the employment of metallic
oxides or salts.
76 kgs. of ammonium sulphocyanide are mixed with 41 kgs. of zinc oxide and 80
kgs. of powdered charcoal, and are heated being at the same time preferably stirred.
At a temperature of from 110° to 160° C. water and a little ammonia are given off.
Whilst the ammonia which is lost is being replaced by the introduction of a stream
of ammonia gas, the temperature is increased to from 160° C. to 175° C. whereby
the decomposition into guanidine sulphocyanide and zinc sulphide is effected. The
former can be separated from the other constituents by lixiviation with water.
The reaction takes place according to the following equation.
2 NH, CNS + ZnO = CN,Hы, HCNS + ZnS + H₂O
If it be desired to employ a metallic salt. then instead of the 41 kgs. of zinc
2 NHONS + PbSO, + 2NH, = CNH, HONS + PbS+ (NH),SO,
[Price 8d.]

page_text: A Process for the Preparation of Guanidine Salts.
We, Dr. ALWIN GOLDBERG, School-teacher, of 3, Inselstrasse, Chemnitz Dr.
WILHELM SIEPERMANN, of 259, Hauptstrasse, Kalk, and Dr. Hugo FLEMMING,
of 165, Hauptstrasse, Kalk, all in the German Empire, do hereby declare
the nature of this invention and in what manner the same is to be per-
formed to be particularly described and ascertained in and by the following
statement:-
This invention relates to a process for the preparation of guanidine salts.
By the ordinary processes for the preparation of guanidine by fusing sul-
phocyanide of ammonia, the former can only be obtained as the sulphocy-
anide, and the yield is unsatisfactory; furthermore the decomposition takes place
very slowly.
Now, we have found by experiment that by mixing oxides or salts of the heavy
metals with the ammonium sulphocyanide and heating the mixture in an atmosphere
of ammonia, guanidine sulphocyanide is obtained in larger quantities and in a
shorter time than usual and furthermore that the guanidine sulphocyanide, when
further heated with an equivalent quantity of a salt of a heavy metal in an aminoniacal
atmosphere, is further reacted upon, the guanidine uniting with the acid of the
metallic salt and more guanidine salt being formed from the ammonium sulphocya-

page_text: Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is
1. A process for the preparation of guanidine salts by heating ammonium
sulphocyanide together with a metallic oxide or salt, or a mixture of both, in an
ammoniacal atmosphere or by heating the double ammoniacal salts of the sul-
phocyanide of the heavy metals under the ordinary or increased pressure, substan-
tially as set forth.
2. In a process of the kind described in Claim 1 the admixture of neutral porous
substances, substantially as set forth.
3. Guanidine salts prepared by the process claimed in the first and second claiming
clauses, substantially as set forth.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicants.