Year: 1886

page_text: Date of Application, 21st Oct., 1886.
Complete Left, 19th July, 1887.
Complete Accepted, 19th Aug:, 1887.
I, CARL AUGUST BENNERT of Blaydon on Tyne in the County of Durham Chemist
do hereby declare the nature of this invention to be as follows:-
This Invention has for its object the manufacture or production of a new class of
organic compounds or coloring materials by reactions between amines of the aromatic
series and the Dioxide of sulphur group. The products obtained I designate
Thiamines.
It is known that Aniline absorbs Sulphur Dioxide and that a compound is formed
which is a combination of one molecule of aniline and one molecule of sulphur
dioxide. It is also known that ammonia and some other amines react similarly.
I have found that nearly all aromatic amines form more or less readily such
combinations with sulphur-Dioxide except those aromatic amines which contain an
acid group such as the Hydroxile- Nitro Sulpho- or Carboxile group.
I call these compounds Sulphite-Amines prefixing "Sulphite" to the name of the
amine to distinguish them from the sulphurous acid Salts of the amines which I call
amine Sulphites.
If sulphite amines or amine sulphites be heated in a closed vessel to from 200° to
300° Centigrade (240°-260° C. is generally the preferable temperature) alone or
mixed with a molecule or molecules of the same or of different Amines reactions
take place between the amine or the amines and the dioxide of sulphur group.
I obtain by this process highly colored compounds which contain sulphur and
which are not easily attacked by reagents in addition to certain bye products such as
water ammonia and sulphuric acid.
I obtain the same results by heating amine salts or amine salts mixed with amines
with sulphurous acid salts also by heating an Amine or Amines with compounds or
mixtures capable of yielding Sulphur dioxide under the conditions under which the
dioxide of sulphur group reacts as aforesaid,

page_text: In some cases it is advantageous to add suitable dehydrating substances such as for
instance fused Chloride of Calcium.
I will describe a mode of performing my Invention taking the Sulphite-Aniline as
an example.
Sulphite Aniline is heated in a closed vessel slowly to about 260° Centigrade.
The pressure rises first to from 20 to 30 atmospheres according to the quantity
treated and subsequently falls until a pressure of steam corresponding to the
temperature is reached.
The heating is then still further continued for several hours.
Generally the process is finished in about 10 hours but this time depends on
quantities, pressure and other minor circumstances.
By boiling the resulting substances with water which by preference is acidulated I
remove the bye products.
The resulting mass is insoluble in almost all the commonly used solvents but it is
soluble in cold sulphuric acid.
The mass may be further purified by dissolving in sulphuric acid in the cold and
pouring the solution into water.
Sulphite Aniline may be mixed with one molecule of Aniline heated and treated in
the manner hereinbefore described.
Instead of Aniline another Amine may be used.
The process may be also varied by taking two or more molecules of Amines with
one molecule of a Sulphite Amine and treating them as hereinbefore described.
Dated this 21st day of October 1886.

page_text: I CARL AUGUST BENNERT of Hebburn on Tyne in the County of Durham Chemist
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 :-
This Invention has for its object the manufacture or production of a new class of
organic coloring compounds or materials by reactions between certain amines of the
aromatic series and the dioxide of sulphur group, which organic colouring compounds
or materials so obtained I designate "Thiamines."
They can be used directly for the colouring purposes to which they may be
applicable or they can be used for dyeing and printing after being rendered soluble or
more soluble in water or weak alkaline solutions.
Aniline absorbs sulphurdioxide Anhydrous sulphurous acid and an unstable
compound is formed which is a combination of one molecule of aniline and one
molecule of sulphurdioxide-Nearly all amines of the aromatic series form more or
readily such combinations with sulphurdioxide except those which contain an acid
group such as the Hydroxyl-, Nitro-, Sulpho-, or Carboxyl-, group.
I will call herein these combinations "Sulphiteamines" prefixing " sulphite" to the
names of the amines to distinguish them from the sulphurous acid salts of the amines
which I call "Aminesulphites.'
If certain Sulphiteamines or Aminesulphites of the aromatic series be heated in a
closed vessel alone or mixed with a molecule or molecules of the same or of different
amines reactions take place between the amine or the amines and the dioxide of
sulphur group. The temperature which I find to answer best is from 240° to 300°
Centigrade (464 to 572° Fahrenheit).
I obtain by this process highly coloured compounds which contain sulphur and
which are not easily attacked by reagents-I shall deal with the bye products after
describing the mode of performing my invention.
It is not necessary to employ the sulphurdioxide or sulphurous acid in a state of
combination with an amine as mechanical mixtures will answer and so will also for
instance an aminechlorhydrate with sodiumsulphite or sodiumbisulphite.
The results of my invention are obtained whenever sulphurdioxide or sulphurous
acid are caused to act upon certain amines of the aromatic series under the conditions
of a closed vessel and an elevated temperature as hereinbefore mentioned.
By addition of fused chloride of calcium (which acts only as a dehydrating means)
in the proportion of say about the quantity of the other compounds employed the
temperature at which this reaction takes place can be lowered in some cases to nearly
2000 centigrade (392° F.) To go higher than 300° Centigrade (572° F.) has no
practical utility.

page_text: I will now describe methods of carrying out my invention taking sulphiteaniline as
an example.
Example I.-Sulphiteaniline is slowly heated in a closed vessel with or without
stirring to about 250° Centigrade (482° F.) The pressure in the vessel usually rises
to from 30 to 40 Atmospheres according to the quantity heated and becomes stationary
at a pressure of steam about corresponding to the temperature.
The heating is then further continued for several hours-Generally the process is
finished in about 10 hours but the time and pressure it will be readily understood
depend on quantities and other minor circumstances.
In any case care has to be taken that the connecting tube between the vessel and 1
the pressure gauge is not stopped up by subliming material.
The resulting mass is removed and may be purified by boiling with water which
by preference is acidulated whereby the bye-products are in great measure
removed.
The said mass is almost insoluble in most or all of the commonly used solvents but 1
it is soluble in cold concentrated sulphuric acid.
The mass may be further treated by dissolving in sulphuric acid in the cold
and pouring the solution into water-The precipitate which forms may then be
filtered off.
Example II. Sulphiteaniline is mixed with one molecule of aniline and is heated 2
in a closed vessel and may be treated as described in Example I.
Example III. Sulphiteaniline is mixed with two or more molecules of aniline and
is heated in a closed vessel and may be treated as described in Example I.
In this case it is advantageous to blow off any excess of aniline employed.
The bye products which are formed by these reactions are principally water, 2
sulphate of ammonia, and a white mass-Small quantities of other coloured substances
and of sulphuretted hydrogen are also formed and usually found.
The yield is more or less satisfactory in about inverse proportion to the quantity of
the aforesaid white mass It is therefore desirable to prevent the formation of this
white mass as much as possible Its formation may be in great measure avoided by 3
the addition of Nitrocompounds to the substances to be treated thereby obtaining a
mixture of the amine or amines with Nitro compounds and Sulphurdioxide.
Instead of Nitrocompounds I sometimes use Azoxy-, Azo-, or Hydrazo-,
compounds In Examples VI VII and VIII I take Azoxybenzol Azobenzol and
Hydrazobenzol as examples.
I may make the addition of one of the said compounds at the beginning of the
process and when a Nitro compound is used also during an interruption of the
process.
To describe the mode of performing the process I give the following Examples (the
parts are by weight).
Example IV.-5 parts Sulphiteaniline
3