Improvements in the Manufacture of Azo-dyes, and in the Produc- tion of Black Shades on Cotton or other Vegetable Fibre or on Silk.
Year: 1895

page_text: Date of Application, 15th Jan., 1895
Complete Specification Left. 14th Oct. 1895 Accented 16th Nov. 1395
Date of Application, 15th Jan., 1895
Complete Specification Left. 14th Oct. 1895 Accented 16th Nov. 1395
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Azo-dyes, and in the Produc-
tion of Black Shades on Cotton or other Vegetable Fibre or on
Silk.
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 & Soda Fabrik of
Ludwigshafen-on-Rhine, in the Empire of Germany) to be as follows
:-
My foreign correspondents have discovered that when preparing mono-azo dyes
by the combination of diazo compounds with 1.1' amidonaphthol-4-sulpho-acid or
with 1.1' amido naphthol-4-sulphoacid according to the methods known prior to
this invention (see the Specification of Letters Patent No. 7713 of 1891), a quantity
of dis-azo dye is frequently formed simultaneously which renders the product
impure and causes loss or waste of the materials einployed, but no method was
known of preparing these azo-dyes with certainty in a pure homogeneous state.
The present invention includes modifications in the said methods whereby the
process is improved and pure uniform mono-azo dyes can invariably be obtained with
absolute certainty.
The said mono-azo dyes have, prior to this invention, been used in the impure
state mentioned in the preparation of dis-azo dyes suited for dyeing black shades on
wool or like animal fibre.
According to this invention a process is provided whereby it is possible to use
certain mono-azo compounds derived from the aforesaid amido-naphthol-sulpho-
acids in the production of dark green or blue to black shades on cotton or other
vegetable fibre or on silk, by combining them, on the fibre, with a further quantity
of a suitable diazo or tetrazo compound.
THE PRODUCTION OF THE NEW, OR IMPROVED, PURE UNIFORM MONO-AZO-
COLOURING MATTERS.
The modifications which it is necessary to introduce into the process, as hitherto
described, vary according to the nature of the diazo compound which it is desired
to combine with the amido-naphthol sulpho acid.
(1.) When using a diazo-compound derived from amido compounds containing a
uitro group or nitro groups, or containing two or more halogen radicles or
substituting groups of both these kinds, it is necessary, in order to avoid with
certainty the production of dis-azo products, to cause the combination to take place
in mineral acid solution without the addition of sodium acetate. My foreign
correspondents have thus discovered that products result when the diazo compounds
and components hereinbefore defined are combined in the presence of mineral acid
different from those which are obtained upon effecting the combination of the same
materials in acetic acid solution. A difference of this nature has hitherto been
unknown.
In working with this class of diazo-compounds, in some cases it is not sufficient
to take merely so much acid as to render the solution strongly acid to test paper;
in order to prevent the formation of dis-azo-dyes it is necessary, particularly when

page_text: using poly-halogenized or poly-nitro-diazo compounds, that a large proportion of
mineral acid should be present.
The amount to be used in every case, both with reference to diazo compounds
containing the acid substituting groups, and such as are not so substituted, can be
determined by the preliminary test conducted in the following manner :-
Prepare the diazo compound in the usual way as if for use in the ordinary manner
for the production of the azo-dyes. Next ascertain if sufficient acid is present for
the purposes of this invention in the following way. To a portion of the acid diazo
solution so prepared add the equivalent quantity of the amido-naphthol-sulpho acid
taken, using in the form of a solution containing five per cent. of the sodium salt.
The mineral acid present must at least be in such excess that the liquid is at all
times plainly acid to Congo-paper. Stir until the diazo compound has disappeared,
then make a test portion alkaline by adding a dilute caustic solution then boil and
dilute the solution obtained with water and pour out a few drops onto filter paper.
If the colour on the filter paper appears perfectly uniform the amount of acid
present in the solution is sufficient to prevent the formation of dis-azo dyes but if
a darker bluer zone should shew itself this indicates the formation of dis-azo dye-
stuff and more acid must be added to the original solution and the test repeated
until the desired result is obtained. In the case of such diazo-compounds where
not only the dis-azo dyes are of a blue colour but the mono-azo dyes are also blue
in alkaline solution it is necessary to acidify the colour on the paper when the
contrast between the dark coloured dis-azo body (if any be present) and the mono-
azo-dye will become apparent. An instance of this case is furnished by the azo-dyes
from para-nitraniline.
If, in carrying out the above test, the union of the diazo compound and the
amido-naphthol-sulpho acid be too much hindered by the presence of the mineral
acid this must be weakened by dilution with water. In carrying out the above test
if desired the amido-naphthol sulpho acid need not be in the form of sodium salt but
the free acid may be used if suspended in water in a fine state of division.
By the use of this test my foreign correspondents have found that a large number
of diazo compounds yield the desired pure uniform mono-azo-dyes with the amido-
naphtol-sulpho-acids hereinbefore mentioned if about one per cent. free hydrochloric
acid be present in the solution. In the case of polyhalogenized or poly-nitro-diazo
compounds more strongly acid solutions are necessary containing say about five per
cent. free hydrochloric acid. This quantity of acid does not injuriously affect the
union of the diazo compounds and the amido naphthol sulpho acids, which proceeds
even in a ten per cent. acid solution.
a
(2.) In the production of the uniform dyes not containing the substituting nitro-
or halogen groups as hereinbefore explained, the presence of mineral acid is as a
rule unnecessary and acetic acid can be used but in order to obtain the desired
uniform mono-azo-dyes it is necessary that the amido-naphthol-sulpho acid should
be present in the form of free acid and not as alkali salt. These conditions herein-
before set forth can best be fulfilled by mixing the equivalent quantities of diazo-
compound and amido-naphthol sulpho acid in the presence of a mineral acid. The
quantity of the latter requisite can be determined by a preliminary test effected in
manner analogous to that already described. To this acid mixture sodium
acetate solution is added gradually so that at the moment when the mineral acid is
completely replaced by acetic acid there is an excess of this latter present, and
the formation of the sodium salt of the amido-naphthol-sulpho acid is prevented
and consequently no dis-azo dye results. When the amount of acetic acid requisite
has once been ascertained it can be directly added as glacial acetic acid instead of
using a mineral acid and sodium acetate. It will be readily understood that
although the di-azo compounds can be divided into two classes differing from one
another in point of their behaviour when used for the production of the pure
uniform mono-azo-dyes as herein before explained, nevertheless there are members
in both classes which approach in their behaviour those of the other class more
nearly than do others. In every case the test herein before given affords reliable

page_text: THE PRODUCTION OF DARK TO BLACK SHADES ON COTTON OR SILK.
In the production of blackish shades on cotton goods by means of azo-dyes,
only substantive dyes could be used prior to this invention. These were either
such as themselves gave the dark shades required, or were capable of being
diazotized on the fibre and then the desired colour was developed by combination
with some suitable amido, or phenolic body.
My foreign correspondents have discovered a process by means of which certain
mono-azo-dyes derived from the amido-naphthol-mono-sulpho acids bereinbefore
mentioned although they possess practically no affinity for cotton, can be used for
the production of fast black shades both on cotton or silk. For this purpose the
goods to be dyed are padded with a solution of the mono-azo-dyes and then these
áre converted into black disazo-dyes on the fibre by combination with a further
proportion of diazo- or tetrazo-compound. These compounds can also be used in
the form of the corresponding nitrosamine compounds, when they are padded on
the goods simultaneously with the mono-azo-dyes.
The azo-dyes which appear to be most valuable for the purpose of this invention
are those derived from non-sulphonated bases and in particular those obtained
from naphthylamine and the poly halogenized amines. And for the development
of the black shades fast to washing the diazotised compounds from polyhalogenized
bases and from tolidine and the like appear most valuable. Although instances of
mono-azo-dyes and of developing diazotized bodies are here mentioned as yielding
valuable results the invention is not restricted to the products thus named. If, at
the developing stage of the process, the diazo- or tetrazo-compounds of non-
substituted aromatic amines be used, it is, in many cases, desirable, in order to
readily achieve good results, to apply them in the form of nitrosamine salts.
Tf, in this process, mono-azo-dyes be used which are not homogeneous but
contain admixed disazo dyes, such as were obtained prior to this invention, the
results obtained are not so favourable, for even shades cannot be easily developed
and the disazo dye which is merely brought mechanically upon the fibre readily
rubs or washes off and is not merely lost for all useful purposes but constitutes in
this way a positive disadvantage. If desired the two parts of the invention can
be more closely united by effecting the preparation of the mono-azo-dyestuff or
dis-mono-azo dyestuff on the fibre itself as well as the development of the black
disazo-dye.
وال
The following examples will serve to illustrate the nature of the invention but
they are merely typical cases and can be varied without departure from the nature
of the invention. The parts are by weight.

page_text: hundred and forty-three parts of alpha-naphthylamine, sixty nine parts of sodium-
nitrite, four hundred parts of hydrochloric acid (containing about thirty per cent.
real acid HCI) and the requisite quantity of ice and water and mix this solution
with about two hundred and forty parts of free 1.1' amido-naphthol-4'-sulpho acid
suspended in water in a fine state of division. Add the requisite quantity of
hydrochloric acid, or glacial acetic acid, as indicated by the test herein before
described. Then run in a saturated solution of sodium acetate, taking the quantity
equivalent to the hydrochloric acid (both free and combined with diazo compound)
stir continuously until the diazo-naphthalene can no longer be detected in the
liquid. Work up in the usual way.
In the same way the homogeneous mono-azo-dyes can be obtained from beta-
naphthylamine, aniline, para-toluidine and the like, using in each case the test
herein before described as a guide to the quantity of acid to be employed which is
thus seen to be much less than in the case of alpha-naphthylamine.
PREPARATION OF A HOMOGENEOUS
MONO-AZO-COLOURING
MATTER
FROM
ALPHA-NAPHTHYLAMINE AND 1.11 AMIDO-NAPHTHOL-4-SULPHO-ACID.
Prepare a solution of diazo-naphthalene in the usual way from about two
hundred and eighty six parts of alpha-naphthylamine, seven hundred and eighty
parts of hydrochloric acid (containing about thirty per cent. real acid) and one
hundred and forty parts of sodium nitrite. Add sufficient water and ice to make
in all twelve thousand by weight. The solution then contains about six tenths per
cent. free hydrochloric acid. Run into this solution five hundred and thirty parts
by weight of the sodium salt of 1.1' amido-naphthol-4-sulpho-acid dissolved in ten
thousand parts of water. Stir well and see that the mixture shews all the time a
distinct reaction due to free mineral acid. This can be seen by testing with
Congo-paper. Continue stirring whilst keeping the mixture cool until the diazo-
compound can no longer be recognized in the solution.
Instead of the sodium salt of the amido-naphthol-sulpho-acid four hundred and
eighty parts of the free acid can be used.
In the same way the homogeneous mono-azo-dyes can be obtained from beta-
naphthylamine, aniline, ortho- or para-toluidine, meta- or para-nitro-aniline, and
the like.
When using the non-nitrated bases it is advisable to dilute the solution, after
mixing, to about twice its volume. In this way the formation of the dye is effected
more rapidly.
PREPARATION OF A HOMOGENEOUS
PARA-DICHLORO-DIAZO-BENZENE
ACIDS.
MONO-AZO-COLOURING MATTER FROM
AND THE AMIDO NAPHTHOL-SULPHO-
Mix about two hundred and forty parts of amido naphthol sulpho acid (1.1.4 or
1.1.4) with about five thousand parts of water and the quantity of hydrochloric
acid (containing about thirty per cen'. real acid) indicated by the test, in this case
say about one thousand one hundred parts. Add a solution of para dichloro-diazo-
benzene prepared in the well known way from about one hundred and sixty two
parts of para dichlor-aniline, seventy parts of sodium nitrite and six hundred parts
of hydrochloric acid (containing about thirty per cent. real acid). Stir the mixture
until the diazc-compound has disappeared.
In the same way the homogeneous mono-azo-dyes can be obtained from ortho-
dichlor aniline, trichlor-aniline (1:2:4:6 or 1:2:4:5) chlor-nitro-aniline (NH, :
NO, Cl=1:2:4) or from dinitro-aniline (1:2:4) and the like.
:

page_text: .
parts of Turkey red oil in ten thousand parts of water add about two hundred
parts of para-nitro phenyl nitrosamine. Pad the cotton goods with this solution
and allow to dry. Next expose the goods for about twelve hours to the atmosphere
wash with soap, and dry
PRODUCTION OF A BLACK
EXAMPLE VI.
COLOUR ON COTTON PREPARING THE MONO AZO
DYE ON THE FIBRE.
Pad the cotton goods with a solution containing about two and a half per cent. of
the sodium salt of the 1.1' amido naphthol 4' sulpho acid. Allow to dry then pass
the goods through a solution containing about two per cent. of para-dichloro-diazo-
benzene acetate.
The cotton assumes, for a moment, a red violet colour due to the
formation of the mono azo dye. This is at once converted into disazo dye and, a
black shade is produced.
EXAMPLE VII.
PRODUCTION OF A BLACK SHADE ON COTTON USING TETRAZO TOLIDINE AS
DEVELOPER.
Pad the goods with mono azo dye as described in Example IV then put the
prepared goods into a solution containing about one per cent. tetrazo ditolyl acetate
work the goods in this solution until the following test shews that the operation is
complete. Tear off a portion of the material and immerse in a hot two per cent.
soda solution if the operation be not complete the characteristic violet colour of
the alkaline solution of the mono azo dye will be noticed Next wash with water and
then with hot solution of an alkaline soap. This hot washing is in this case
essential as it appears that only one diazo group of tetrazo compounds is effective
in the development of the colour and the remaining free diazo group must be
destroyed.
PREPARATION OF A BLACKISH GREEN SHADE ON COTTON WITH 1.1 AMIDO
NAPHTHOL 4¹ SULPHO ACID AND NITRO PHENYL NITROSAMINE.
Dissolve about twenty four parts of the sulpho acid in two hundred parts of

page_text: water containing five parts of caustic soda and add a solution of forty parts
of sodium para nitro phenyl nitrosamine in about eight hundred parts of water.
Pad the cotton with this solution. Allow to dry and expose to the atmosphere for
about twenty four hours, and wash first with water alone and then with soap.
In this case also the intermediate production of mono azo dye soluble in alkali
can be noticed.
Dated this 15th day of January 1895.
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, London, W.C., Agents
Improvements in the Manufacture of Azo-dyes, and in the Produc-
tion of Black Shades on Cotton or other Vegetable Fibre or on
Silk.
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 & 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 :-
My foreign correspondents have discovered that when preparing mono-azo-dyes
by the combination of diazo-compounds with 1.1' amidonaphthol-4-sulpho acid or
with 1.1 amidonaphthol-4-sulphoacid according to the methods known prior to
this invention (see the Specification of Letters Patent No. 7713 of 1891) a
quantity of dis-azo-dye is frequently formed simultaneously, which dis-azo-dye
renders the product impure, and causes loss, or waste, of the materials employed
and no method was, prior to this invention, known of preparing these mono-azo-
dyes with certainty in a pure homogeneous state, The present invention includes
modifications in the said methods whereby the process is improved so that pure
and uniform mono-azo-dyes can invariably be obtained with absolute certainty.
The said mono-azo-dyes have prior to this invention, been used, in the impure
state mentioned, in the preparation of dis-azo-dyes suited for dyeing black shades
on wool, or like animal fibre. According to this invention a process is provided
whereby it is possible to use certain mono-azo-compounds or dis-mono-azo-com-
pounds derived from the aforesaid amido-naphthol-sulphoacids in the production
of dark green, or blue to black, shades on cotton, or other vegetable fibre, or on
silk, by combining them, on the fibre, with a further quantity of a suitable diazo,
or tetrazo, compound.
THE PRODUCTION OF THE NEW, OR IMPROVED PURE UNIFORM MONO-AZO-
COLOURING MATTERS.
The modifications which it is necessary to introduce into the process as known
prior to this invention vary according to the nature of the diazo-compound which
it is desired to combine with the amidc-naphthol-sulphoacid. (1.) When using a
diazo-compound derived from amido-compounds containing a nitro-group or nitro-
groups or containing two, or more, halogen radicles, or substituting groups, or both
these kinds, it is necessary, in order to avoid with certainty the production of
dis-azo products, to cause the combination to take place in mineral acid solution
without the addition of sodium acetate. My foreign correspondents have thus

page_text: discovered that products result, when the diazo-compounds and components nerein-
before defined are combined in the presence of mineral acid, which products are
different from those which are obtained upon effecting the combination of the same
materials in acetic acid solution. A difference of this nature was unknown prior
to this invention.
In working with this class of diazo compounds in some cases, it is not sufficient
to take merely so much acid as to render, the solution strongly acid to test paper.
In order to prevent the formation of dis-azo-dyes it is necessary, particularly when
using poly-halogenized, or poly-nitro-diazo-compounds, that a larger proportion of
mineral acid should be present.
The amount to be used in every case, both with reference to diazo-compounds
containing the acid substituting groups, and such as are not so substituted, can be
determined by the preliminary test conducted in the following manner :-
Prepare the diazo-compound in the usual way as if for use, in the ordinary
manner, for the production of the azo-dyes, but taking sufficient acid to prevent
the formation of die-azo-dyes on combining. Ascertain if sufficient acid is present
for the purposes of this invention in the following way. To a portion of the acid
diazo-solution so prepared add the equivalent quantity of the amido-naphthol
sulpho acid taken, using it in the form of a solution containing five per cent. of the
sodium salt. The mineral acid present must at least be in such excess that the
liquid is at all times plainly acid to Congo-paper. Stir until the diazo-compound
has disappeared, then make a test-portion alkaline by adding a dilute caustic
soda solution, then boil and dilute the solution obtained with water, and pour out
a few drops onto filter paper. If the colour on the filter paper appear perfectly
uniform the amount of acid present in the solution is sufficient to prevent the
formation of dis-azo-dyes but if a darker blue zone should shew itself this indicates
the formation of disazo-dye-stuff and more mineral acid must be added to the
In the
original solution and the test repeated until the desired result is obtained.
case of using diazo-compounds where not only the dis-azo-dyes are of a blue
colour but the mono-azo-dyes are also blue in alkaline solution, it is necessary to
acidify the colour on the paper when the contrast between the dark-coloured
dis-azo-body (if any be present) and the mono-azo-dye will become apparent. An
instance of this case is furnished by the azo-dyes from para-nitraniline.
If, in carrying out the above test, the union of the diazo-compound and the
amido-naphthol-sulpho acid be too much hindered by the presence of the mineral
acid, this must be weakened by dilution with water. In carrying out the above
test, the amido-naphthol-sulpho acid need not be in the form of sodium salt, as the
free acid may be used if suspended in water in a fine state of division.
By the use of this test my foreign correspondents have found that a large number
of diazo-compounds yield, with the amido-naphthol-sulpho acids bereinbefore
mentioned, the desired pure uniform mono-azo-dyes, if about one per cent. of free
hydrochloric acid be present in the solution. In the case of polyhalogenized, or
poly-nitro-diazo, compounds, more strongly acid solutions are necessary, containing
say about five per cent. of free hydrochloric acid. This quantity of acid does not
injuriously affect the union of the diazo-compounds and the amido-naphthol-sulpho
acids, which proceeds even in a ten per cent. acid solution.
(2.) In the production of the uniform dyes not containing the substituting nitro,
or halogen groups as hereinbefore explained, the presence of mineral acid is, as a
rule, unnecessary, and acetic acid can be used, but in order to obtain the desired
uniform mono-azo-dyes, it is necessary that the amido-naphthol-sulpho acid should
be present in the form of free acid, and not as alkali salt. No claim is made, in
this application, for the process of combining in acetic acid solution. These
conditions herein before set forth can best be fulfilled by mixing the equivalent
quantities of diazo-compound and amido-naphthol-sulphoacid in the presence of a
mineral acid. The quantity of the latter requisite can be determined by a
preliminary test effected in a manner analogous to that already described. It will
be readily understood that although the diazo-compounds can be divided into two

page_text: classes differing from one another in their behaviour when used for the production
of the pure uniform mono-azo-dyes as hereinbefore explained, nevertheless there
are members in both classes which approach in their behaviour those of the other
class more nearly than do others. In every case the test hereinbefore given affords
reliable guidance
as to the treatment which is most advantageous. As an instance
hereof, mention, that the diazo-compound of alpha-naphthylamine behaves in a
manner similar to the nitro-diazo-compounds in its combination with 1.1' amido-
aphthol-4-sulpho-acid, but not so much so in its combination with 1.1'-amido-
naph: hol-4-sulpho-acid. In the former case the test shews that it is practically
necessary to perform the reaction in the presence of a mineral acid without the
addition of acetic acid, whereas in the latter case, although it is necessary in order
to obtain the homogeneous dyes to use a very large proportion of acetic acid, still
under these conditions the formation of the desired homogeneous product can be
effected. It is however so advantageous to use mineral acid instead of the large
quantity of acetic acid taken, that, in practice, the latter method would never be
used, and no claim is made thereto.
THE PRODUCTION OF DARK ΤΟ BLACK SHADES ON COTTON, OR OTHER
VEGETABLE FIBRE, OR SILK.
In the production of blackish shades on cotton goods by means of azo-dyes, only
substantive dyes could be used prior to this invention. These were either such as
themselves gave the dark shades required, or were capable of being diazotised on
the fibre and then the desired colour was developed by combination with some
suitable amido-, or phenolic-, body.
My foreign correspondents have discovered a process by means of which certain
mono-azo-dyes, derived from the amido-naphthol-mono-sulpho acids herein before
mentioned, although they possess practically no affinity for cotton, can be used for
the production of fast black shades either on cotton or other vegetable fibre or silk.
According to the same process dis-mono-azo-dyes can also be used. For this
purpose the goods to be dyed are padded or otherwise impregnated with a solution
of the mono-azo-dyes, or dis-mono-azo-dyes, and then these are converted into
black dis-azo-dyes on the fibre, by combination with a further proportion of diazo-
or tetrazo-compound. These compounds can also be used in the form of the
corresponding nitrosamine compounds, when they are padded on the goods simul-
taneously with the mono-azo-dyes.
The azo-dyes which appear to be most valuable for the purpose of this invention
are those derived from non-sulphonated bases, and in particular those obtained from
naphthylamine and the poly halogenized and nitro-amines, and for the development
of black shades fast to washing, the diazotized compounds from polyhalogenized
bases, and from tolidine, and the like, appear most valuable. Although instances
of mono-azo-dyes and of developing diazotized bodies are here mentioned as
yielding valuable results, the invention is not restricted to the products thus named.
If, at the developing stage of the process, the diazo, or tetrazo, compounds of non-
substituted aromatic amines be used, it is, in many cases, desirable, in order to
readily achieve good results, to apply them in the form of nitrosamine salts.
If, in this process, mono-azo-dyes be used which are not homogeneous but
contain admixed dis-azo-dyes, such as were obtained prior to this invention, the
results obtained are not so favourable, for even shades cannot be easily developed
and the dis-azo-dye which is merely brought mechanically upon the fibre readily
rubs or washes off, and is not merely lost for all useful purposes, but constitutes in
this way a positive disadvantage.
If desired the two stages of the reaction can be more closely united by effecting
the preparation of the mono-azo-dyestuff or dis-mono-azo-dyestuff on the fibre
itself, as well as the development of the black dis-azo-dye. This is only

page_text: advantageous when the same diazo-compound is used for the production of the
mono-azo-dye, and for developing the dis-azo-dye.
The following examples will serve to illustrate the nature of the invention but
they are merely typical cases and can be varied without departure from the nature
of the invention. The parts are by weight.
PREPARATION OF A HOMOGENEOUS
MONO-AZO-COLOURING-MATTER
ALPHA-NAPHTHYLAMINE AND 1.1 AMIDO-NAPHTHOL-4-SULPHO ACID.
FROM
Prepare, in the usual way, a solution of diazo-naphthalene from about two
hundred and eighty six parts of alpha-naphthylamine, seven hundred and eighty
parts of hydrochloric acid (containing about thirty per cent, real acid HCl) and one
hundred and forty parts of sodium nitrite. Add sufficient water and ice to make
in all twelve thousand parts. The solution then contains about six-tenths per cent.
of free hydrochloric acid. Run into this solution five hundred and thirty parts of
the sodium salt of the 1.1' amido-naphthol-4-sulpho acid dissolved in ten thousand
parts of water. Stir well and see that the mixture shews, all the time, a distinct
reaction due to free mineral acid. This can be seen by testing with Congo-paper.
Continue stirring whilst keeping the mixture cool until the diazo-compound can no
longer be recognized in the solution.
Instead of the sodium salt of the amido-naphthol-sulpho acid four hundred and
eighty parts of the free acid can be used.
In the same way the homogeneous mono-azo-dyes can be obtained from meta- or
para nitro-aniline and the like. Also from the isomeric 1.1' amido-naphthol-
4-sulpho acid and alpha naphthylamine and the bases mentioned.
PREPARATION OF A HOMOGENEOUS
MONO-AZO-COLOURING
FROM
MATTER
PARA-DICHLORO-DIAZO-BENZENE AND THE AMIDO NAPHTHOL-SULPHO-
ACIDS
;
Mix about two hundred and forty parts of amido naphthol sulpho acid (1.1.4
or 1.1.4) with about five thousand parts of water and the quantity of hydro-
chloric acid (containing about thirty per cent. real acid) indicated by the test in
this case say about one thousand one hundred parts. Add a solution of para-
dichloro-diazo benzene prepared in the well known way from about one hundred
and sixty two parts of para-dichlor-aniline, seventy parts of sodium nitrite, and six
hundred parts of hydrochloric acid (containing about thirty per cent. real acid).
Stir the mixture until the diazo-compound has disappeared.
In the same way the homogeneous mono-azo-dyes can be obtained from
ortho-dichlor-aniline, tri-chlor-aniline (1:2:4:6 or 1:2:4:5), chlor-nitro
aniline (NH, NO2: Cl=1:2: 4) or from dinitro aniline (1:2:4) and the like.
EXAMPLE III.
PRODUCTION OF A DEEP BLACK COLOUR ON COTTON.
Dissolve about one hundred parts of the mono-azo-dye obtained from para-
dichlor-aniline and 1.1 amido naphthol sulpho acid in two thousand parts of water
together with sixty parts of caustic soda (containing about 35 per cent. NaOH)
and add it to and hundred thousand
Dissolve about one hundred parts of the mono-azo-dye obtained from para-
dichlor-aniline and 1.1 amido naphthol sulpho acid in two thousand parts of water
together with sixty parts of caustic soda (containing about 35 per cent. NaOH)
and add it to one hundred thousand parts of a colution
mmon sale (containing
about ten per cent. NaCl). Pass five thousand parts of cotton (yarn or fabric)
through the bath so prepared during about one hour and a half, remove the
adjoined liquid by wringing or hydro extracting, and continue as it is described in
the Examples [V or VII

page_text: PRODUCTION OF A BLACK SHADE ON COTTON USING TETRAZO-TOLIDINE
AS DEVELOPER.
Pad the goods with mono-azo-dye exactly as described in Example IV then put
the prepared goods into a solution containing about one per cent. of tetrazo-ditolyl-
acetate work the goods in this solution until the following test shews that the
operation is complete. Tear off a portion of the material and immerse it in a hot
two per cent. soda solution; if the operation be not complete the characteristic
violet colour of the alkaline solution of the mono-azc-dye will be noticed. Next
wash with water and then with hot solution of an alkaline soap. This hot washing
is in this case essential as it appears that only one diazo group of tetrazo compounds
is effective in the development of the colour and the remaining free diazo group
must be destroyed.
PREPARATION OF A BLACKISH GREEN SHADE ON COTTON WITH 1.1'-AMIDO-
NAPHTHOL 4-SULPHO ACID AND NITRO-PHENYL NITROSAMINE.
Dissolve about twenty four parts of the sulpho acid in two hundred parts of

page_text: water containing five parts of caustic soda and add a solution of forty parts of
sodium para nitrophenyl-nitrosamine in about eight hundred parts of water. Pad
the cotton with this solution. Allow to dry and expose to the atmosphere for about
twenty four hours; and wash first with water alone, and then with soap.
In this case also, the intermediate production of mono-azo-dye soluble in alkali
can be noticed.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed 1 declare that what I
claim is :-
1. The process for the manufacture of pure uniform mono-azo-colouring matters
derived from the aforesaid amido-naphthol-sulpho acids which consists in combining
the amido naphthol sulpho acid with diazo compounds in the presence of a mineral
acid in such quantity as is indicated by the test herein before described.
2. As new articles of manufacture the new pure uniform mono-azo-dyes derived
on the one hand from alpha-naphthylamine or nitro- or poly-halogenized amines,
and on the other hand from the amido-naphthol sulpho-acids herein before mentioned
such as can be obtained substantially as herein before described.
3. The new process for producing black shades upon cotton or other vegetable
fibre or on silk which consists in impregnating the said materials with a mono-azo
compound or a dis-mono-azo-compound derived from the amido-naphthol-sulpho
acids, then treating the same with a further proportion of diazo-compound all
substantially as hereinbefore described.
4. The new process for producing black shades upon cotton or other vegetable
fibre or on silk which consists in impregnating the said materials with a mono-azo-
compound or dis-mono-azo compound derived from amido-naphthol-sulpho acid
then treating the same with a further proportion of a tetrazo compound and
destroying the free diazo group by treatment in a hot soap bath all substantially
as hereinbefore described.
5. In the processes claimed in the foregoing claiming clauses 3 and 4 the use of
the diazo and tetrazo compounds in the form of nitrosamines.
6. The process for the production of the black shades on fibre consisting in the
production of the mono azo dyes from the amido-naphthol-sulpho acids and
their conversion into dis-azo dye in one operation on the fibre substantially as
described.
7. The manufacture of uniform mono-azo dyes in the manners described in
Examples I and II.
8. The production of black shades on cotton in the manners described in
Examples III, IV, V, VI, VII, VIII.
Dated this 14th day of October 1895.
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, London, W.C., Agents.