Improvements in the Manufacture of Colouring-matters, and of New Intermediate Products.
Year: 1897

page_text: Date of Application, 11th Jan., 1897
Complete Specification Left, 11th Oct., 1897-Accepted, 13th Nov., 1897
Improvements in the Manufacture of Colouring-matters, and of New
Intermediate Products.
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 com-
municated to me from abroad by The Badische Anilin and Soda Fabrik, of Lud-
wigshafen-on-Rhine in the Empire of Germany) to be as follows:-
In the specification of the Letters Patent No. 5693 of the year 1893 a process
is described for the production of the acid yellow colouring-matter known as
“Tartrazine.”
وو
The said process consists in treating a hydrazone (obtained from the initial
materials oxalyo-acetic-ether and phenyl-hydrazine-sulpho acid) with diazo sul-
phanilic acid and subsequently saponifying the product obtained. This process
gives such a small yield of colouring-matter that it is not commercially available
and is practically absolutely useless.
CC
My foreign correspondents have discovered a new process for the production of
Tartrazine," and its analogues from the afore-mentioned, or analogous, initial
materials whereby it is possible to obtain a largely increased yield of colouring-
matter from a given quantity of initial materials. The said new process consists
in converting the hydrazone referred to by splitting off alcohol into a new inter-
mediate body belonging to the class of pyrazolones, then combining this with
diazo-sulphanilic acid or other diazo compound.
When proceeding according to the process of the aforesaid Letters Patent No.
5693/93 considerable decomposition takes place, as is shewn by the evolution of
nitrogen.
In the new process according to the present invention the reactions proceed
smoothly and no nitrogen or but a mere trace thereof escapes.
The preparation of the hydrazone can be effected in the manner described in
the Specification of the said Letters Patent No. 5693/93 by mixing together mole-
cular proportions of oxalylo-acetic-ether, sodium acetate and phenyl-hydrazine-
sulpho acid in aqueous suspension. The formation of the hydrazone is complete
as soon as the materials have gone into solution. This takes place in a few minutes
at a temperature of 50° centigrade. This hydrazone is soluble in dilute mineral
acids so that on the addition of dilute sulphuric acid, even after a few minutes
standing, no appreciable precipitate is formed.
The conversion of the hydrazone into the pyrazolone derivative mentioned can
be effected in several ways. It takes place slowly if the reaction liquid be merely
allowed to stand for several days. This change will even take place in the presence
of acids especially hydrochloric acid. It is accelerated by heating, but more
advantageously it is brought about by the action of alkalies, or salts which act
like alkalies; preferably an excess of soda or caustic soda is used. If to the reac-
tion liquid above referred to and containing the hydrazone a molecular proportion
of soda be added, this is neutralized by the acetic acid present and in the presence

page_text: of the sodium acetate formed, the formation of the new pyrazolone will only
take place slowly, especially if the mixture be not heated above the ordinary
temperature.
The manner of formation of the new pyrazolone and its constitution can be seen
from the following equation:—
This new pyrazolone may in accordance with the nomenclature of Anschütz
be called the sodium salt of tartrazinogen-ester-sulpho acid, for on treatment with
diazo-sulphanilic acid it yields tartrazine-ester. It can readily be distinguished
from the hydrazone by the fact that it is almost immediately precipitated by dilute
sulphuric acid and gives the blue colouration typical of the pyrazolones with
ferric chloride.
Analogous tartrazinogen-esters and their sulpho acids can be obtained by the use
of other ethers of oxalylo-acetic-ether or by the use of other hydrazines and their
sulpho or carboxylic acids.
To convert these new tartrazinogen-esters into tartrazines, they may first be
saponified to the corresponding acids (which are also new) and then combined with
diazo-sulphanilic acid (or other diazo-compound), or they may be combined with
the diazo-compound first and the resulting product be saponified.
The following examples will serve to further illustrate the nature of the inven-
tion but the invention is not confined to the examples. The parts are by weight.
EXAMPLE 1.
PREPARATION OF A NEW PYRAZOLONE-DERIVATIVE, TARTRAZINOGEN-ESTER-
SULPHONATE OF SODIUM.
Suspend about nine and a half parts of phenyl-hydrazin-sulpho acid in about
fifty parts of water, stir and add about seven and a half parts of crystallized sodium
acetate. Next add about nine and two fifths parts of oxalylo-acetic-ether, stir and
raise the temperature to about 50 degrees centigrade. Maintain this temperature
until a clear solution results (usually about five minutes). This solution contains
the hydrazone hereinbefore referred to. Cool the solution to the ordinary tempera-
ture and then add from eight to ten parts of calcined soda (sufficient excess to give
a distinctly alkaline reaction). The splitting-off of alcohol and production of the
sodium salt of the tartrazinogen-ester sulpho acid take place rapidly. The course
of the reaction can be followed by taking tests from time to time and adding dilute
sulphuric acid, when the amount of precipitate of the new body obtained shews
the progress of the change. When successive tests shew no increase in the amount
of precipitate the operation is complete. Precipitate the whole with dilute sul-
phuric acid, filter, press and dry.
Th

page_text: water-bath for about half an hour with about one hundred and fifteen parts of
caustic soda lye (containing about 35 per cent. NaOH). Precipitate the new tar-
trazinogen-sulpho acid with hydrochloric acid. It forms a white crystalline pre-
cipitate, which may be collected in the usual way.
If the solution, of the hydrazone obtained as described in Example 1 be directly
heated with caustic soda as described in the foregoing Example 2 the same result
is obtained; that is the formation of the tartrazinogen-ester-sulphonate and its
saponification are effected in one operation.
EXAMPLE 3.
PRODUCTION OF TARTRAZINE FROM TARTRAZINOGEN SULPHO ACID.
For this purpose it is unnecessary to use the isolated body, the solution contain-
ing it in solution as alkali salt as obtained in the foregoing example is preferably
employed. Add to the said solution about seventy five parts of crystallized sodium
acetate and at a temperature of about five to ten degrees centigrade, introduce the
amount of diazo-sulphanilic acid equivalent to thirty four and a half parts of sodium
nitrite; allow to stand in the cold, or at a moderate warmth, for about twenty
hours. Precipitate the tartrazine with common salt, and collect in the usual way. .
EXAMPLE 4.
PRODUCTION OF TARTRAZIN-ESTER FROM TARTRAZINOGEN-ESTER-SULPIIONATE OF SODA.
In this case also it is unnecessary to use the isolated body, indeed the solution
thereof as obtained in Example 1 can better be employed.
Dilute the said solution with water up to about two hundred parts, and at a
temperature of about five to ten degrees centigrade, introduce as much diazo-
sulphanilic acid as is equivalent to 345 parts of sodium nitrite, leave the solution
in the cold, or at a moderate warmth for say about twelve hours stirring
occasionally.
The tartrazine-ester formed can be isolated by salting out and then saponified,
or it can be saponified without previous isolation.
The saponification is best effected by heating with caustic alkali in the water-
bath.
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.
Improvements in the Manufacture of Colouring-matters, and of New
Intermediate Products.
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 com-
municated to me from abroad by The Badische Anilin and Soda Fabrik, of Lud-
wigshafen-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 follow-
ing statement:-
<
In the Specification of the Letters Patent No. 5693 of the year 1893 a process
is described for the production of the acid yellow colouring-matter known as
tartrazine.”
The said process consists in treating a hydrazone (obtained from the initial
materials oxalylo-acetic-ether and phenyl-hydrazine-sulpho acid) with diazo-
sulphanilic acid and subsequently saponifying the product obtained. This process

page_text: gives such a small yield of colouring-matter that it is not commercially available
and is practically absolutely useless.
My foreign correspondents have discovered a new and commercially available
process for the production of "tartrazine," and its analogues from the afore-
mentioned, or analogous, initial materials, whereby it is possible to obtain a
largely increased yield of colouring-matter from a given quantity of initial
materials. The principal new step in the said new process according to this inven-
tion consists in converting by splitting off alcohol the hydrazone referred to, or
its analogues, into a new intermediate body being an ester of an acid belonging
to the class of pyrazolones, and then combining this new intermediate body with
diazo-sulphanilic acid, or other diazo-compound. At some stage of the process the
ester-group is saponified to the free acid as hereinafter described in detail.
When proceeding according to the process of the aforesaid Letters Patent No.
5693 of 1893, considerable decomposition takes place, as is shewn by the evolution
of nitrogen. In the new process according to the present invention the reactions
proceed smoothly and no nitrogen, or but a mere trace thereof, escapes.
The preparation of the hydrazone can be effected in the manner described in
the specification of the said Letters Patent No. 5693 of 1893 by mixing together
molecular proportions of oxalylo-acetic-ether sodium acetate and phenyl-hydrazine-
sulpho-acid in aqueous suspension. The formation of the hydrazone is complete
as soon as the materials have gone into solution. This takes place in a few
minutes at a temperature of 500 centigrade. This hydrazone is soluble in dilute
mineral acids so that, on the addition of dilute sulphuric acid, even after a few
minutes standing, no appreciable precipitate is formed.
The conversion of the hydrazone into the aforesaid pyrazolone derivative can
be effected in several ways. The conversion will take place if the reaction liquid
bc allowed to stand for a time but the conversion then takes place but slowly and
occupies several days. The conversion will also take place in the presence of acids,
especially hydrochloric acid, and it is accelerated by heating. The conversion is
however most advantageously effected by the action of alkalies, or salts which act
like alkalies an excess of soda or caustic soda being preferably used. If to the
reaction liquid above referred to, and containing the hydrazone, a proportion of
soda be added, equivalent to the acetic acid present then this is neutralized by the
said acid and in the presence of the sodium acetate formed, the formation of the
new pyrazolone will only take place slowly, especially if the mixture be not heated
above the ordinary temperature.
The manner of formation of the new pyrazolone and its constitution can be seen
from the following equation:-
ffiffi
This new pyrazolone may (in accordance with the nomenclature of Anschütz)
be called the sodium salt of tartrazinogen-ester-sulpho acid, for, on treatment with
diazo-sulphauilic acid, it yields tartrazine-ester. It can readily be distinguished
from the hydrazone by the fact that it is almost immediately precipitated by dilute
sulphuric acid from its solution (obtained as hereinbefore described) and gives the
blue colouration, typical of the pyrazolones, with ferric chloride,
40

page_text: Analogous tartrazinogen-esters and their sulpho acids can be obtained by the
use of other ethers of oxalylo-acetic-acid or by the use of other hydrazines and
their sulpho, or carboxylic, acids.
To convert these new tartrazinogen-esters into tartrazines, they may first be
saponified to the corresponding acids, (which are also new), and then be combined
with diazo-sulphanilic acid (or other diazo-compound), or they may be combined
with the diazo-compound first and the resulting product be saponified.
The following examples will serve to further illustrate the nature of the inven-
tion and the manner in which it can be performed, but the invention is not con-
fined to these examples. The parts are by weight.
tion and the manner in which it can be performed, but the invention is not con-
fined to these examples. The parts are by weight.
EXAMPLE 1.
PREPARATION OF A NEW PYRAZOLONE-DERIVATIVE, TARTRAZINOGEN-ESTER-
SULPIIONATE OF SODIUM.
Suspend about nine and a half parts of phenyl-hydrazine-sulpho acid in about
fifty parts of water, stir and then add about seven and a half parts of crystallised
sodium-acetate. Next add about nine and two fifth parts of oxalylo-acetic-ether,
stir hnd raise the temperature to about 50 degrees centigrade. Maintain this
temperature until a clear solution results. This usually takes place in about five
minutes. This solution contains the hydrazone herein before referred to. Cool the
solution to the ordinary temperature and then add from eight, to ten, parts of
calcined soda, taking care that there is sufficient excess to give a distinctly alkaline
reaction. The splitting off of alcohol and the production of the sodium salt of the
tartrazinogen-ester-sulpho acid take place rapidly. The course of the reaction can
be followed by taking tests from time to time and adding dilute sulphuric acid,
when the amount of precipitate of the new body obtained shews the progress of
the change. When successive tests shew no increase in the amount of precipitate
the operation is complete. Precipitate the whole with dilute sulphuric acid, filter,
press and d
.
Dissolve about one hundred and sixty seven parts of sodium salt of tartrazinogen-
ester-sulphonate in about two thousand parts of water and warm the solution on
the water-bath for about half an hour with about one hundred and fifteen parts of
caustic soda lye (containing about 35 per cent. NaOH). Precipitate the new
tartrazinogen-sulpho acid with hydrochloric acid. It forms a white crystalline
precipitate which may be collected in the usual way.
If the solution of the hydrazone obtained as described in Example 1 be directly
treated with caustic soda as described in the foregoing Example 2 the same result
is obtained; that is the formation of the tartrazinogen-ester sulphonate and its
saponification are effected in one operation.
EXAMPLE 3.
PRODUCTION OF TARTRAZINE FROM TARTRAZINOGEN SULPHO ACID.
For this purpose it is unnecessary to use the isolated body; the solution con-
taining it in solution as alkali salt as obtained in the foregoing example, being
preferably employed. Add to the said solution about seventy-five parts of crystal-
lized sodium acetate and at a temperature of about five to ten degrees centigrade,
introduce the amount of diazo-sulphanilic acid equivalent to thirty four and a half
parts of sodium nitrite; allow the mixture to stand in the cold, or at a moderate
warmth, for about twenty hours. Precipitate the tartrazine with common salt and
collect in the usual way.

page_text: EXAMPLE 4.
PRODUCTION OF TARTRAZINE-ESTER FROM TARTRAZINOGEN-ESTER-SULPHONATE OF SODA.
In this case also it is unnecessary to use the isolated body, indeed the solution
thereof as obtained in Example 1 is preferred. Dilute the said solution with water
up to about two hundred parts and, at a temperature of about five to ten degrees
centigrade, introduce as much diazo-sulphanilic acid as is equivalent to 3'45 parts
of sodium nitrite, leave the solution in the cold, or at a moderate warmth for say
about twelve hours, stirring occasionally. The tartrazine-ester formed can be
isolated by salting out and then saponified, or it can be saponified without previous
isolation. The saponification is best effected by heating with caustic alkali on the
water-bath.
Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed I declare that what I
claim is:
1. The manufacture and production of new intermediate products of the class of
pyrazolone-esters by splitting off alcohol from the hydrazones derived from
oxalylo-acetic ether or other ethers of oxalylo-acetic acid and phenyl-hydrazine-
sulpho acid or other hydrazines or their sulpho or carboxylic acids; substantially
as hereinbefore described.
2. The manufacture of tartrazine and its analogues by preparing the new pyra-
zolone-esters such as are herein before described and claimed in the preceding
claiming clause and combining them with diazo-sulphanilic acid, or other diazo-
compound, and saponifying the esters to the acids, before, or after, this combina-
tion with a diazo-compound; substantially as herein before set forth.
3. The manufacture and production of the new intermediate products being the
new esters and acids of the pyrazolone series herein before defined and of tartrazine-
ester and tartrazine in the manners set forth in the examples..
4. As new articles of manufacture the new intermediate products such as can
be obtained from hydrazone or its analogues as hereinbefore described.
Dated this 11th day of October 1897
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, London, W.C., Agents,