The Manufacture and Production of Azo-dyes of the Benzidine and analogous Series.
Year: 1895

page_text: Date of Application, 1st Apr., 1895 ·
Complete Specification Left, 20th Dec., 1895-Accepted, 1st Feb., 1896
PROVISIONAL SPECIFICATION.
The Manufacture and Production of Azo-dyes of the Benzidine and
analogous Series.
I JAMES YATE JOHNSON of 47 Lincoln's Ion Fields in the County of
London Gentleman do hereby declare the nature of this invention (which has
been communicated to me from abroad by The Badische Anilin & Soda Fabrik
of Ludwigshafen on Rhine in the Empire of Germany) to be as follows:-
Prior to this invention the important series of substantive cotton dyes derived
from benzidine tolidine, dianisidine or their analogues have been manufactured
solely by combining the tetrazo compounds of the diamido-bases referred to, with
amines, phenols, amido-phenols or their sulpho or carboxylic acids.
My foreign correspondents have devised a new process for the manufacture of
dyes of this class whereby it is possible to obtain colouring matters agreeing in
their properties with the well known substantive cotton dyes, and also, in some
cases, new products can be obtained.
The said new process consists in suitably treating mono-azo-dyes with an
oxydizing agent. Thereby the molecules of the mono-azo-dye become coupled
together in pairs. The course of the reaction may be illustrated by the following
where B signines the residue of aniline or other amido compound and
azodye component.
A au
My foreign correspondents have found that the new process can be very
generally applied to mono-azo-dyes and the disazo-dyes corresponding thereto be
obtained. Mixtures of mono-azo dyes can also be treated by the new process and
mixed disazo-dyes be obtained. As instances of mono-azo-dyes which can be
successfully used I mention those derived from aniline ortho-toluidine and ortho-
anisidine on the one hand, and alpha- and beta-naphthol-sulpho-acids, alpha- and
beta napthylamine-sulpho acids, amido naphthol-sulpho acids and salicylic acid on
the other hand. These instances will serve to illustrate the general applicability
of the process but the invention is not confined to the application of the process to
the mono-azo-dyes above named.
As instance of oxidizing agents which can be used I mention pyrolusite,
manganese peroxide ammonium persulphate and lead superoxide, but the invention
is not restricted to the use of these particular agents.
To effect the reaction the mono-azo-dye to be used is dissolved in concentrated
sulphuric acid and the oxidation agent chosen (for instance manganese peroxide)
is stirred into the solution. In some cases the mixture is kept cold, in others it is
necessary, or preferable, to heat it. The progress of the reaction can be followed
by noticing the change in colour of a solution of a test portion in concentrated
sulphuric acid as the colour changes from that given by the mono-azo-dye to that
of the sulphuric acid solution of the disazo body. Thus in the case of aniline
azo-naphthionic acid the solution changes from red towards blue. If the oxidation
be carried too far in any way destruction of material, and a damaged or worthless
product may result.

page_text: The following example will serve to further illustrate the nature of the invention
but the details can in all cases be varied. The parts are by weight.
EXAMPLE.
MANUFACTURE OF A SUBSTANTIVE RED DYE.
Dissolve about thirty five parts of the mono-azo-dye, aniline-azo-naphthionic
acid in about three hundred parts of concentrated sulphuric acid (containing about
ninety two per cent. real acid H.SO.) and add to the solution about twenty parts
of crude manganese peroxide (containing about fifty per cent. MnO,). During the
addition of the oxidizing agent and throughout the operation the mass is constantly
stirred and is cooled so that the temperature does not rise above twenty to
twenty five degrees Centigrade. When in successive tests no further formation of
disazo-dye is noticeable isolate the disazo dye formed. To effect this pour on to
ice with or without the addition of an agent that will destroy any excess of
oxidizing agent present; such as for instance sulphurous acid then filter wash with
hot water, convert into sodium salt and purify if necessary by redissolving and
reprecipitating with common salt in the usual way.
Dated this 1st day of April 1895.
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, London, W.C., Agents.
EVITICATION.
The Manufacture and Production of Azo-dyes of the Benzidine and
analogous Series.
I, JAMES YATE JOHNSON, of 47 Lincoln's Inn Fields, in the County of London,
Gentleman, do hereby declare the nature of this invention (which has been
communicated to me from abroad by The Badische Anilin and Soda Fabrik of
Ludwigshafen-on-Rhine, in the Empire of Germany) and in what manner the
same is to be performed to be particularly described and ascertained in and by
the following statement :-
Prior to this invention the important series of substantive cotton dyes derived
from benzidine, tolidine, dianisidine, or their analogues, have been manufactured
solely by combining the tetrazo compounds of the diamido-bases referred to, with
amines, phenols, amido-phenols, or their sulpho, or carboxylic acids.
My foreign correspondents have devised a new process for the manufacture of
dyes of this class, whereby it is possible to obtain colouring matters agreeing in
their properties with the well known substantive cotton dyes and also, in some
cases, new products can be obtained.
The said new process consists in suitably treating mono-azo dyes with an
oxydizing agent, whereby the molecules of the mono-azo dye become coupled
together in pairs. The course of the reaction may be illustrated by the following
scheme:
H-B-N= N = X
B
+0= |
-
N = N X
1
+ H₂O
H-B NN-X
B-N-N- X
where B signifies the residue of aniline or another amido-compound with the
para-position free and X an azo-dye component.
My foreign correspondents have found that tha

page_text: obtained. As instances of mono-azo-dyes which can be successfully used I mention
those derived from aniline, ortho-toluidine, ortho-anisidine, and anthranilic acid, on
the one hand, and alpha and beta-naphthol-sulpho acids, alpha- and beta-naph-
thylamine-sulpho-acids and amido-naphthol-sulphoacids, on the other hand; also
amido-azo-benzene and its analogues. These instances will serve to illustrate the
general applicability of the process but the invention is not confined to the
application of the process to the nono azo dyes above named. Mixtures of mono-
azo-dyes can also be treated by the new process and mixed dis-azo-dyes be
obtained. As instances of such mixtures which my foreign correspondents have
successfully treated in this way, I mention :-aniline-azo-naphthionic acid and
anisidine-azo-naphthionic acid, aniline-azo-beta-naphthol-disulphoacid R and aniline-
azo-beta-naphthol, aniline-azo-1. 4 naphthol-sulpho-acid and aniline-azo-amido-
naphthol-disulpho-acid H and aniline-azo-amido-naphthol-sulpho acid and
ortho-toluidine-azo-naphthionic acid.
Y
When oxidizing mono-azo-dyes from anisidine two series of dis-azo-dyes are
obtained which are apparently iscmeric with one another. Thus the mono-uzo dye
from anisidine and beta-naphthol-disulpho acid R yields, on oxidation, a dis-azo-dye
derived from para-dianisidine whilst the corresponding dye from 1.4 naphthol-
sulphoacid yields a new dis-azo colouring matter which is of a tint more reddish
than that of the colouring matter obtained from para-dianisidine and 1.4 naphthol-
sulphoacid.
As instances of oxidizing agents which can be used I. mention pyrolusite,
manganese peroxide, ammonium persulphate, and lead superoxide, but the invention
is not restricted to the use of these particular agents.
To effect the reaction the mono-azo-dye to be used is dissolved in concentrated
sulphuric acid and the oxidation agent chosen (for instance, manganese peroxide)
is stirred into the solution. In most cases, the mixture should be carefully kept
cold. The progress of the reaction can, as a rule, be followed by noticing the
change in colour of a solution of a test portion in concentrated sulphuric acid, as
the colour changes from that given by the mono-azo dye to that of the sulphuric
acid solution of the disazo body. Thus in the case of aniline-azo-naphthionic acid
the solution changes from red to blue. If treatment with the oxidizing agent and
acid be carried too far in any way, destruction of material, and a damaged or
worthless product, may result. If unchanged mono-azo-dye be contained in the
product it can often be removed by converting the mixture into the sodium, or
calcium, salts, and taking advantage of the different solubility of the mono-
and dis-azo-bodies either in water, or in common salt solutions, the dis-azo-
bodies are less soluble.
The following examples will serve to further illustrate the nature of the invention
and the manner in which it can be carried into practical effect but the details can
in all cases be varied without departing from the invention. The parts are by
weight.
EXAMPLE 1.
Dissolve about thirty-five parts of the mono-azo dye, aniline-azo-naphthionic
acid, in about three hundred parts of concentrated sulphuric acid, (containing
about ninety-two per cent.. real acid H₂SO4), and add to the solution about twenty
parts of crude manganese peroxide (containing about fifty per cent. MnO₂).
During the addition of the oxydizing agent, and throughout the operation, the
mass is constantly stirred, and is cooled so that the temperature does not rise
above twenty to twenty-five degrees Centigrade. When, in successive tests, no

page_text: DXAMPLE 4
Run about sixteen hundred parts of concentrated sulphuric acid (containing about
ninety-five per cent. H,SO) into a vessel provided with a thoroughly efficient
stirrer, and cool the acid to about ten degrees below zero. Centigrade, then
add, gradually during about three-quarters of an hour to an hour, about one
hundred and fifteen parts of finely powdered sifted ortho-toluidine-azo-naphthionate
of soda. Stir continuously and take care that the temperature does not rise above
zero Centigrade. After the addition. of the mono-azo-dye is effected continue
stirring for about three quarters of an hour, whilst cooling once more to ten
degrees below zero, then add, gradually during about one hour, about fifty-two
parts of finely powdered manganese peroxide, (containing about eighty per cent.
MnO,), taking care that the temperature does not rise above zero Centigrade..
Continue stirring for about two hours, or until a test portion yields a pure blue
solution in a large proportion of sulphuric acid. Then pour the entire melt into a
mixture of about fifteen hundred parts of ice, and five thousand parts of water
containing about one hundred and eighty parts of sodium bisulphite solution,
(containing about twenty-five per cent. of SO). Stir for half an hour and then
filter, stir the filter-cake with five thousand parts of water, filter again. Mix the
filter cakes again with fifteen thousand parts of water, and neutralize with calcined:
soda, of which one thousand to thirteen hundred parts will be necessary; boil and
filter hot, say at ninety five degrees Centigrade, and to the hot solution, say at
seventy to eighty degrees Centigrade, add about two thousand five hundred to
three thousand parts of saturated common salt solution, in order to precipitate the
colouring matter. Filter, press, and dry.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what I
-claim is :-
1. The manufacture of symmetrical azo-dyes of the benzidine, or analogous
series, by the oxidation of the mono-azo colouring matters herein before defined
substantially as described.
2. The manufacture of mixed azo-dyes of the benzidine, or analogous, series,
by the oxidation of the mixtures of mono-azo-colouring matters hereiubefore
defined, substantially as described.
3. In the manufacture of dis-aze-colouring matters by the oxidation of mono-
azo colouring matters treating the latter with an oxidizing agent, whilst dissolved
in concentrated sulphuric acid.
4. The manufacture of substantive azo-dyes in the manners herein described
in the examples.
Dated this 20th day of December 1895.
JOHNSONS & WILLCOX,
Agents.