Improvements in the Manufacture of Azo Dyes.
Year: 1896

page_text: Date of Application, 3rd Feb., 1896
Complete Specification Loft 2nd Nov 1896 Accepted. 12th Dec., 1896
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Azo Dyes.
I, SYDNEY PITT of Sutton in the County of Surrey Gentleman do hereby declare
the nature of this invention (as communicated to me from abroad by Leopold
Cassella & Co. of Frankfort on Main in the Empire of Germany) to be as follows:-
Azo dyestuffs which contain a hydroxyle and carboxyle group in the ortho position,
such as the derivatives of salicylic acid possess as is known, the property of forming
with chrome mordants difficultly soluble lakes. This property is however not so
pronounced as with the alizarine dyestuffs, and a brown azo dyestuff for instance
which would be in all respects equal to anthragallol fixed with chrome (anthracene
brown) has not yet been found amongst the azo derivatives of salicylic acid. My
foreign correspondents have succeeded by introducing two groups of salicylic acid
into the molecule of azo dyestuffs in increasing their mordant dyeing property to such
a degree that the fastness to washing of dyeings fixed with chrome is not inferior to
that of alizarine dyestuffs.
The new colouring matters are derived from metadiamines and result from these by
combining them with diazo bodies of the formula:
CH₂
- OH
COOH
_N=N_X - NH
(in which X-NH, represents an amine as for instance alpha naphtylamine) in such a
way that the metadiamines are combined either direct with two molecules of these
diazo azo bodies or first with diazo salicylic acid and then with one molecule of the
diazo-azo body. The shades of the direct as well as of the chromed dyeings are
throughout dark brown which undergo a certain alteration in consequence of the
formation of the chrome lake as is the case with all derivatives from salicylic acid. If
nitroumidosalicylic acid is used, a change of shade is not perceptible. The derivatives
of nitroamidosalicylic acid are technically the most valuable ones of the group, as the
introduction of the nitro group also increases the fastness to light and gives
the dyestuffs the yellow cast which is so much desired. The shades may also be
changed at will towards red or black by varying the interposed amine designated
by X in the foregoing formula. The darkest shades of brown are obtained, by
applying alpha-naphtylamine; specially easily soluble products of the same shade
result, if instead of the latter alpba, naphty lamine beta, or beta, sulpho acid is used.
Lighter shades are obtained by using amines of the benzene group. In this case one
starts either from the para-amidobenzolazosalicylic acid which is for instance obtained
by reducing the dye-stuff from para-nitrodiazobenzol and salicylic acid with sodium
sulphide or from the products which result from diazosalicylic acid (or diazo-
nitrosalicylic acid) and para-xylidine or para-amidocresolether.
The following example will serve to illustrate the nature of the invention. The parts.
are by weight.

page_text: of nitrite of soda and the diazo compound brought together with 28.6 parts of
alpha-naphtylamine in a weak solution of muriatic acid. When the combination is
terminated, the dyestuff is filtered off, then dissolved in soda lye, 14 parts of nitrite
of soda added thereto and the mixture acidulated at about 0° C. A brown difficultly
soluble diazo-azo-body is thus formed which is filtered off and introduced into a 5
solution of 10-8 parts of meta-phenylenediamine which is kept alkaline with soda.
The dyestuff separates after a short time in the shape of a dark brown precipitate.
2ND EXAMPLE.
15-3 parts of amidosalicylic acid are diazotised with 7 parts of nitrite of soda and
the diazo compound is brought together with 11 parts of meta-phenylenediamine in a 1
weak alkaline solution. From the resulting orange yellow solution the very easily
soluble dyestuff is precipitated with acetic acid. Then it is dissolved again by means
of soda and to the solution is added the diazo-azo compound produced from 19-8 parts
of nitroamidosalicylic acid and 14.3 parts of alpha-naphtylamine in the manner
described in Example 1. The dyestuff separates in the form of a dark brown 1
precipitate.
D
C1
1000
Improvements in the Manufacture of Azo Dyes.
I, SYDNEY PITT, of Sutton, in the County of Surrey, Gentleman, do hereby declare
the nature of this invention (as communicated to me from abroad by Leopold
Cassella & Co. of Frankfort on Main 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 :-
Azo dyestuffs which contain a hydroxyle and carboxyle group in the ortho position
such as the derivatives of salicylic acid possess as is known, the property of forming
with chrome mordants difficultly soluble lakes. This property is however not so
pronounced as with the alizarine dyestuffs, and a brown azo dyestuff for instance
which would be in all respects equal to anthragallol fixed with chrome (anthracene
brown) has not yet been found amongst the azo derivatives of salicylic acid. My
foreign correspondents have succeeded by introducing two groups of salicylic acid
into the molecule of azo dye-stuffs in increasing their mordant dyeing property to such
a degree that the fastness to [washing of dyeings fixed with chrome is not inferior to
that of alizarine dyestuffs.
The new coloring matters are derived from metadiamines and result from these by
combining them with diazo bodies of the formula :
OH
CH, COOH
-N=N-X − NH
(in which X - NH, represents an amine as for instance alpha naphtylamine) in such a
way that the metadiamines are combined either direct with two molecules of these
diazo azo bodies or first with diazo salicylic acid and then with one molecule of the
diazo-azo body. The shades of the direct as well as of the chromed dyeings are
throughout dark brown which undergo a certain alteration in consequence of the
formation of the chrome lake as is the case with all derivatives from salicylic acid. If
nitroamidosalicylic acid is used, a change of shade is not perceptible. The derivatives
(in which X-NH, represents an amine as for instance alpha naphtylamine) in such a
way that the metadiamines are combined either direct with two molecules of these
diazo azo bodies or first with diazo salicylic acid and then with one molecule of the
diazo-azo body. The shades of the direct as well as of the chromed dyeings are
throughout dark brown which undergo a certain alteration in consequence of the
formation of the chrome lake as is the case with all derivatives from salicylic acid. If
nitroamidosalicylic acid is used, a change of shade is not perceptible. The derivatives

page_text: 0
5
of nitroamidosalicylic acid are technically the most valuable ones of the group, as the
ntroduction of the nitrogroup also increases the fastness to light and gives
the dyestuffs the yellow cast which is so much desired. The shades may also be
changed at will towards red or black by varying the interposed amine designated
by in the foregoing formula. The darkest shades of brown are obtained by
applying alpha-naphtylamine; specially easily soluble products of the same shade
result, if instead of the latter, alpha, naphtylamine beta, or beta, sulpho acid is used.
Lighter shades are obtained by using amines of the benzene group. In this case one
starts either from the para-amidobenzolazosalicylic acid which is for instance obtained
by reducing the dye-stuff from para-nitrodiazobenzol and salicylic acid with sodium
sulphide or from the products which result from diazosalicylic acid (or diazo-
nitrosalicylic acid) and para-xylidine or para-amidocresolether.
The following examples will serve to illustrate the nature of the invention. The
parts are by weight.
1ST EXAMPLE.
39-6 parts of nitroamidosalicylic acid (1. 3. 4. 5) are diazotised with 14 parts
of nitrite of soda and the diazo compound brought together with 28-6 parts of
alpha-naphtylamine in a weak solution of muriatic acid. When the combination is
terminated, the dye-stuff is filtered off, then dissolved in soda lye, 14 parts of nitrite
of soda added thereto and the mixture acidulated at about 0° C. A brown. difficultly
soluble diazo-azo-body is thus formed which is filtered off and introduced into a
solution of 10-8 parts of meta-phenylenediamine which is kept alkaline with soda.
The dye-stuff separates after a short time in the shape of a dark brown precipitate.
2ND EXAMPLE.
15-3 parts of amidosalicylic acid are diazotised with 7 parts of nitrite of soda and
the diazo compound is brought together with 11 parts of ineta-phenylenediamine in a
weak alkaline solution. From the resulting orange yellow solution the very easily
soluble dye-stuff is precipitated with acetic acid. Then it is dissolved again by means
of soda and to the solution is added the diazo-azo compound produced from 19.8 parts
of nitramidosalicylic acid and 14-3 parts of alpha-naphtylamine in the manner
described in Example 1; the dyestuff separates in the form of a dark brown
precipitate.
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
5 I claim is :-
1. The production of brown coloring matters by combining meta-phenylenediamine
or meta-toluylenediamine either
(a) With two molecules of the diazoazocompounds which are obtained by
diazotizing the azocombinations formed by the action of diazosalicylic or
diazonitrosalicylic acid on alpha-naphtylamine, alpha-naphtylamine-beta sulpho
acid, paraxylidine, para-amidocresolether or
(b) With one molecule of these diazoazocompounds and one molecule of
diazosalicylic acid or diazonitrosalicylic acid, substantially as described.
2. The new coloring matters which can be obtained according to Claim 1
substantially as described.
27th day of October 1896.