The Manufacture of New Azo-dyes, and of Materials for Producing the same.
Year: 1895

page_text: Date of Application, 15th May, 1895
Complete Specification Left, 14th Feb., 1896-Accepted, 14th Mar., 1896
PROVISIONAL SPECIFICATION.
The Manufacture of New Azo-dyes, and of Materials for Producing
the same.
I, SYDNEY PITT, of Sutton, in the County of Surrey, Gentleman, (a communi-
cation to me from abroad by Leopold Cassella & Co., of 18 Liebigstrasse,
Frankfort-on-Main, in the Empire of Germany, Manufacturing Chemists,) do
hereby declare the nature of this invention to be as follows:-
A nitroamidosalicylic acid of the melting point of 220° C. has been obtained by
Babcock from dimetanitrosalicylic acid (Berichte der Deutschen Chemischen
Ges. XII, p. 1345); it is transformed into alphanitrosalicylic acid (melting
point 228° C.) by replacing the amido group with hydrogen, and consequently has
the following constitution:
The new acid results, when the amidooxybenzoic acid 1. 4. 5. (p. amidosalicylic
acid) is nitrated in a sulphuric acid solution at a low temperature. The nitration
may be effected by observing the necessary precaution without oxidation or
elimination of the carboxyle group.
Example: 77 kilos. free amidooxybenzoic acid are dissolved in 350 kilos.
sulphuric acid of 66° Bé.; the mixture is cocled down to 0 to 5° C., and whilst it
is kept cool, 110 kilos. of a mixture of nitric and sulphuric acid containing
30% HNO3 are slowly introduced. When all bas run in, the temperature is
raised within hour to 15° C., and the mixture is then rapidly diluted with ice.
Hereby the nitro acid is almost completely separated, whilst any parts of
unchanged amido acid remain dissolved in the form of its sulphate. Then the
precipitate is filtered off and washed out with water.
As for technical use principally the diazo compound of the acid is of importance,
the diluted nitration may be directly diazotised and the very difficultly soluble
diazo-nitrooxybenzoic acid isolated. As this method of isolation renders it possible
to purify the product by a simple method, it is not absolutely necessary to start
from the pure p. amidosalicylic acid.
It is
The amidonitrooxybenzoic acid melts and is decomposed at 240° C.
difficultly soluble in boiling, almost insoluble in cold water and can be crystallised
therefrom in the shape of shining leaves. It is almost insoluble in chloroform,
ligroine, benzole. The free acid has a very light yellowish colour. Its salts
show characteristic colorings. The neutral salts are of an orange colour and
crystallise easily. The sodium salts can be easily obtained in the shape of brown
short prisms. The basic salts are of an intense crimson red and most of them
easily soluble. Treated with nitrite of soda the acid is transformed into the almost
insoluble diazo acid having a light yellow colour which reacts very energetically
with amines and phenoles.
Both acids the 1. 5. 2. 3. as well as the new 1. 3. 4. 5. acid have been found to be
very useful for the production of azo colours.

page_text: The dyestuffs derived from the diazo compounds of the said acids prove in many
respects superior to the known azo derivatives from amidooxybenzoic acid,
principally with regard to their fastness to light.
In general the 1. 5. 2. 3. acid gives bluer shades than the 1. 3. 4. 5. acid; the
derivatives of the latter-however possess certain advantages as for instance giving
more easily level dyeings.
The process of producing the mono azo dyestuffs is shown by the following
example:
20 kilos. 1. 3. 4. 5. amidonitrooxybenzoic acid are in the well known manner
transformed into the very difficultly soluble yellowish diazo compound. The latter
is then introduced into a solution of 36 kilos. beta-naphtoldisulpho acid R kept
alkaline by means of carbonate of soda. The formation of the dyestuff takes place
at once. The dyestuff which separates in the shape of a brown precipitate is
filtered off after the combination has been completed. It dyes wool in an acid bath
red. By alumina or chrome mordants the color is completely fixed.
In an analogous manner other combinations are obtained for instance by replacing
the R salt with a₁ α, α₁ α, ß₁ ẞ naphtolmonosulpho acid, a₁ a dioxynaphtalene-
mono- or disulpho acid or the like.
Disazo dyestuffs are produced by combining diazonitrooxybenzoic acid with one
molecule of a diazotisable amine, such as a naphtylamine, ai B₁ amidonaphtolether,
a Banaphtylaminesulpho acid, p. xylidine, amido-p-cresolether and combining
the thus obtained amidoazo body after the diazotation has taken place, with amines
or phenoles.
Example: 20 kilos. amidonitrooxybenzoic acid 1. 3. 4. 5. are diazotised and
brought together in presence of free mineral acid with 14.4 kilos. a naphtylamine.
Hereby the dark violet almost insoluble acid of the dyestuff is formed which by the
addition of alkalies can be transformed into the likewise very difficultly soluble
sodium salt. The diazotation of the amideazo compound with 7 kilos. nitrite of
soda is executed in the usual manner; it produces the diazoazo acid in the shape
of a brown almost insoluble precipitate. This is filtered off and introduced into a
solution of 36 kilos. beta-naphtoldisulpho acid R kept alkaline with carbonate of
soda. A blue black precipitate of the completed dyestuff forms immediately which
is filtered off and dried. It dyes wool in an acid bath a blue black fast to washing.
By the action of alumina or chrome mordants dyeings are obtained perfectly fast
to milling.
In an analogous manner numerous combinations can be made for instance, by
replacing the R salt with B₁ B3; ß ß; a α2 or α a naphtolmonosulpho acid or
by replacing the a napbtylamine with other diazotisable amines such as named
above.
Dated this 15th day of M. 1905
COMPLETE SPECIFICATION.
The Manufacture of New Azo-dyes, and of Materials for Producing
the same.
I, SYDNEY PITT, of Sutton, in the County of Surrey Gentleman, (a communi-
cation to me from abroad by Leopold Cassella & Co. of 19 Liebigstrasse,
Frankfort-on-Main, in the Empire of Germany, Manufacturing Chemists) 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:―
A nitroamidosalicylic acid of the melting point of 220° C. has been obtained by
Babcock from dimetanitrosalicylic acid (Berichte der Deutschen Chemischen

page_text: Ges. XII, p. 1345); it is transformed into alpha-nitrosalicylic acid melting
point 228° C., by replacing the amido group with hydrogen and consequently has
the following constitution."
My foreign correspondents have now produced an isomeric acid of great t
value which according to their investigations has the constitution :-
NH, NO, OH: COOH = 1 : 3:4: 5.
·
==
The new acid results, when the amidooxybenzoic acid 1. 4. 5. (p. amidosalicylic
acid) is nitrated in a sulphuric acid solution at a low temperature.
The nitration may be effected by observing the necessary precaution without
oxydation or elimination of the carboxyle group.
Example: 77 kilos. free amidooxybenzoic acid are dissolved in 350 kilos.
sulphuric acid of 66° Bé.; the mixture is cooled down to 0° to 5° C., and whilst it
is kept cool, 110 kilos. of a mixture of uitric and sulphuric acid containing 30 per
cent. HNO, are slowly introduced. When all has run in, the temperature is
raised within half an hour to 15° C., and the mixture is then rapidly diluted with
ice. Hereby the nitro acid is almost completely separated, whilst any parts of
unchanged amido acid remain dissolved in the form of its sulphate. Then the
precipitate is filtered off and washed out with water.
As for technical use principally the diazo compound of the acid is of importance,
the diluted nitration may be directly diazotised and the very difficultly soluble
diazo-nitrooxybenzoic acid isolated. As this method of isolation renders it possible.
to purify the product by a simple method, it is not absolutely necessary to start
from the pure p. amidosalicylic acid.
The amidonitrooxybenzoic acid melts and is decomposed at 240° C. It is
difficultly soluble in boiling, and almost insoluble in cold, water and can be
crystallised therefrom in the shape of shining leaves. It is almost insoluble in
chloroform, ligroine, benzole. The free acid has a very light yellowish colour.
Its salts show characteristic colorings. The neutral salts are of an orange color
and crystallise easily. The sodium salts can be easily obtained in the shape of
brown short prisms. The basic salts are of an intense crimson red and most of
them easily soluble. Treated with nitrite of soda the acid is transformed into the
almost insoluble diazo acid having a light yellow color which reacts very
energetically with amines and phenoles.
Both acids the 1. 5. 2. 3. as well as the new 1. 3. 4. 5 acid have been found to be
very useful for the production of azo colors.
The dyestuffs derived from the diazo compounds of the said acid prove in many
respects superior to the known azo derivatives from amidooxybenzoic acid,
principally with regard to their fastness to light.
In general the 1. 5. 2. 3 acid gives bluer shades than the 1. 3. 4. 5. acid; the
derivatives of the latter however possess certain advantages as for instance giving
more easily level dyeings.
The process of producing the mono azo dyestuffs is shewn by the following
example:
20 kilos. 1. 3. 4. 5 amidonitrooxybenzoic acid are in the well known manner
transformed into the very difficult soluble yellowish diazo compound. The latter
is then introduced into a solution of 36 kilos. beta-naphtoldisulpho acid R kept
alkaline by means of carbonate of soda. The formation of the dyestuff takes place
at once. The dyestuff which separates in the shape of a brown precipitate is
filtered off after the combination has been completed. It dyes wool in an acid bath
red. By alumina or chrome mordants the color is completely fixed.
In an analogous manner other combinations are obtained for instance by
replacing the K salt with a a, a, a, B₁ B naphtolmonosulpho acid, a₁ a dioxy-
naphtalenemono- or disulpho acid or the like.

page_text: Disazo dyestuffs are produced by combining diazonitrooxybenzoic acid with one
molecule of a diazotisable amine, such as a naphtylamine, a₁ B, amidonaphtolether,
Banaphtylaminesulpho acid, p. xylidine, amido-p-cresolether and combining
the thus obtained amidoazo body after the diazotation has taken place, with
amines or phenoles, such as phenol, resorcine, naphtol, dioxynaphtalene, amido-
naphtol, primary or secondary naphtylamines, or the sulphonic or carbonic acids
thereof.
Example: 20 kilos. amidonitrooxybenzoic acid 1. 3. 4. 5. are diazotised and
brought together in presence of free mineral acid with 14.4 kilos. a naphtylamine.
Hereby the dark violet almost insoluble acid of the dyestuff is formed which by
the addition of alkalies can be transformed into the likewise very difficultly soluble
sodium salt. The diazotation of the amidoazo compound with 7 kilos. nitrite of
soda is executed in the usual manner; it produces the diazoazo acid in the shape
of a brown almost insoluble precipitate. This is filtered off and introduced into a
solution of 36 kilos. beta-naphtoldisulpho acid R kept alkaline with carbonate of
soda. A blue black precipitate of the completed dyestuff forms immediately which
is filtered off and dried. It dyes wool in an acid bath a blue black fast to washing.
By the action of alumina or chrome mordants dyeings are obtained perfectly fast
to milling.
In an analogous manner numerous combinations can be made for instance by
replacing the R salt with B₁ B; B₁ ẞ4; a₁ α, or a₁ as naphtolmonosulpho acid or
by replacing the a naphtylamine with other diazotisable amines such as named
above.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is
1. Producing 1. 3. 4. 5 amidonitro oxybenzoic acid by nitrating p. amido-salicylic
acid in a sulphuric acid solution substantially as described.
2. Producing new azo dyestuffs by combining the diazo derivatives of 1. 5. 2. 3
or of 1. 3. 4. 5 amidonitro oxybenzoic acid,
(a) With amines or phenoles.
(b) With a diazotisable amine, treating with nitrous acid and further
combining with amines or phenoles substantially as described.
3. As a new article of manufacture the 1. 3. 4. 5 amidonitro oxybenzoic acid
hereinbefore described.
4. As new articles of manufacture the coloring matters which can be obtained
by the processes herein before described.
Dated this 20th day of January 1896.
OVANDY DIRT
Y PITT
זזזז
AMNGAS