Manufacture and Production of a New Diazo Compound for Use in Dyeing and Printing.
Year: 1894

page_text: Date of Application, 8th Feb., 1894
Complete Specification Left, 8th Nov., 1894--Accepted, 8th Dec., 1894
PROVISIONAL SPECIFICATION.
Manufacture and Production of a New Diazo Compound for Use in
Dyeing and Printing.
I, Dr. JULIUS ALTSCHUL, Chemist, of 45 Woodland Street, Cheetham Hill,
Manchester, do hereby declare the nature of this invention to be as follows:-
The introduction of the process of dyeing and printing nitraniline red (as obtained
on cotton, impregnated with ẞ naphtol, by passing the same through a solution
of a salt of para nitrodiazobenzene) has hitherto been greatly retarded by the
difficulties, which the dyers and printers have found in preparing the said diazo
solution.
The object of my invention is to provide the dyer and printer with a new
compound, obtained from paranitroaniline, which can be converted into a nitro-
diazobenzene solution in a more convenient manner riz. by simply dissolving the said
compound in acids.
I obtain the new product, above mentioned (and which shall be referred to as
Nitroaniline S in this Specification) by diazotising paranitroaniline in a somewhat
concentrated solution, then allowing the diazo solution obtained, to run into a cold
solution of caustic soda in excess, care being taken to prevent a rise of temperature,
and precipitating the new compound formed, by the addition of common salt.
Nitroaniline S is thus obtained in the form of a brownish yellow crystalline
precipitate, which can easily be separated from the mother liquor by the usual
methods of filtring, pressing etc. and is then dried at low temperature. If necessary,
it may be purified by dissolving it in water and precipitating it again from the
filtered solution by adding a strong solution of common salt, in which it is nearly
insoluble, whereas it is readily soluble in water.
When the aqueous solution of nitraniline S is treated with acids, it will at first
yield a precipitate of a yellowish white colour. On standing, this precipitate
dissolves and a solution of the nitrodiazobenzene salt of the acid used, is obtained.
For use in dyeing and printing, this solution is simply diluted to the strength
required, and if mineral acid has been used, an equivalent quantity of sodium
acetate should be added.
From its qualities and its transformation by acids, into nitrodiazobenzene salts,
nitraniline S appears to be the sodium salt of para nitrodiazobenzene and to be the
first genuine sodium salt of a diazo compound hitherto described, as the metal salts
of diazobenzene, obtained by Griess (Annalen der Chemie und Pharmazie 137)
have been proved by Curtius (Berichte der Deutschen Chemischen Gesellschaft
XXIII, 3035) to be of an altogether different composition.
From the sodium salt, above described, salts with other metals can be obtained
by usual methods.
The details of the process of preparing the new product and of converting it
into a solution suitable for developing nitroaniline red, may be varied considerably,

page_text: Manufacture and Production of a New Diazo Compound for Use in
Dyeing and Printing.
I, Dr. JULIUS ALTSCHUL, Chemist of 45 Woodland Street, Cheetham Hill,
Manchester, 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 :-
The introduction of the process of dyeing and printing nitraniline red (as obtained
on cotton impregnated with beta-naphthol by passing the same through a solution
of a salt of paranitrodiazobenzene) has hitherto been greatly retarded by the
difficulties which the dyers and printers have found in preparing the said diazo
solution.

page_text: The object of my invention is to provide the dyer and printer with a new
compound obtained from paranitraniline which can be converted into a nitrodiazo-
benzene solution in a more convenient manner, viz. by simply dissolving the said
compound in acids.
I obtain the new product above mentioned (and which shall be referred to as
"Nitraniline S" in this Specification) by diazotising paranitraniline in a some-
what concentrated solution allowing the diazo solution obtained to run into a
cold solution of caustic soda in excess, care being taken to prevent a rise of
temperature, and by precipitating the new compound formed, by the addition of
common salt.
If
"Nitraniline S" is thus obtained in the form of a brownish yellow crystalline
precipitate which can easily be separated from the mother liquor by the usual
methods of filtering, pressing &c., and is then dried at low temperature.
necessary, it may be purified by dissolving it in water and precipitating it again
by adding a strong solution of common salt, in which it is nearly insoluble, whereas
it is readily soluble in water.
When the aqueous solution of nitraniline S is treated with acids it will at first
yield a precipitate of yellowish white colour. On standing, this precipitate dissolves
and a solution of the nitrodiazobenzene salt of the acid used is obtained. For use
in dyeing and printing, this solution is simply diluted with cold water to the strength.
required, and if mineral acid has been used, an equivalent quantity of sodium acetate
should be added.
From its qualities and its transformation by acids into the nitrodiazobenzene
salts, nitraniline S appears to be the sodium salt of paranitrodiazobenzene and to
be the first genuine sodium salt of a diazo compound hitherto described as the
metal salts of diazo benzene obtained by Griess (Ann. Chem. Pharm. 137) have
been proved by Curtius (Ber. d. Deutsch. Chem. Ges. XXIII 3035) to be of an
altogether different composition. From the sodium salt above described, salts with.
the other metals can be obtained by usual methods.
The details of the process for preparing the new product and for converting it
into a solution suitable for developing paranitraniline red may be varied a good
deal without materially affecting the result.
The following description is therefore only given as an example and I do not
confine myself to the proportions or other details given in it.

page_text: AKETARAITOA FROM NITRANILINE DUE THE DIAZO
DEVELOPING NITRANILINE RED.
2 kilos. nitraniline S are stirred into a mixture of
5
"
2
2
"
"
hydrochloric acid 36° Tw.
water
ice, and allowed to stand being occasionally stirred until the
precipitate formed at first, has dissolved. The solution is filtered,
diluted with cold water to about 200 litres and before using, has
added to it.
7 kilos. sodium acetate dissolved in
50 litres cold water.
The diazo solution prepared in this way, yields a very bright and brilliant red
on cotton bottomed with beta naphthol.
Having now particularly described and ascertained the nature of this inven-
ion and in what, manner the same is to be performed, I declare that what I
laim is
1. The manufacture of a new compound, obtained from paranitraniline by
liazotising paranitraniline in a somewhat concentrated solution, running the diazo
solution thus obtained into an excess of a cold solution of alkali and precipitating
by common salt the new compound thus formed substantially as described.
2. As a new product the new compound, obtained from paranitraniline as set
forth in the preceding claim.
3. The adaptation of the new compound above referred to for dyeing and
printing by converting it into a nitrodiazobenzene solution, substantially as
lescribed.
Dated this 8th day of November 1894.
ABEL & IMRAY,
Agents for the Applicant.