The Manufacture and Production of New Compounds suited for Use in the Preparation of Diazo Compounds, and their Application in the Production of Dyes.
Year: 1893

page_text: Date of Application, 31st Oct., 1893
Complete Specification Left, 31st Aug., 1894-Accepted, 27th Oct., 1894
PROVISIONAL SPECIFICATION.
The Manufacture and Production of New Compounds suited for Use
in the Preparation of Diazo Compounds, and their Application in
the Production of Dyes.
I, JAMES YATE JOHNSON, of 47 Lincoln's Inn Fields in the County of
Middlesex, Gentleman, do hereby declare the nature of this invention (which
has been communicated to me from abroad by The Badische Anilin and
Soda Fabrik of Ludwigshafen-on-Rhine, in the Empire of Germany) to be as
follows:-
In the production of certain shades of colour by means of one well-known
process the dyer combines diazo-compounds with amines or phenols on or in the
presence of, the fibre. As the diazo-compounds generally are an extremely
unstable class of bodies, it is necessary that they should be prepared in the
dyeing factory as they cannot practically be transported. The preparation of the
diazo-compounds for the purpose in question is frequently inconvenient or
difficult as the best result can only be attained by careful and accurate observance
of certain narrowly bounded conditions. Moreover the conditions which are best
for obtaining the diazo compounds sometimes yield these bodies admixed with
acids and salts in such quantity that the product is not well suited for use in the
aforesaid dyeing process.
My foreign correspondents have discovered that the diazo compound of para-
nitro-aniline on treatment with caustic soda is converted into the sodium salt of
the isomeric nitrosamine compound which is a readily crystallizable compound that
can easily be isolated and possesses considerable stability. This product yields no
dye even on standing in the presence of naphthol and an excess of alkali. By
treatment with one molecular proportion of an acid this sodium salt is converted
into the free nitrosamine which is less stable than the sodium salt but which can, if
desired, be prepared and used in the form of paste. On treatment with a larger
proportion of acid, preferably in the presence of a little nitrous acid, the new
nitrosamine is smoothly and readily reconverted into the diazo-compound. Thus
by means of this invention it is possible to prepare a stable compound capable of
transport which can easily be converted into diazo compound ready for use in the
aforesaid dyeing process.
The processes above described can be applied to the production of similar
compounds from other diazo-compounds besides that of para-nitro-aniline. The
diazo compounds which are capable of use are principally those derived from such
amines as contain one or more substituting acid groups such for instance as nitro
groups, halogens, sulpho-groups and the like. Bodies containing acid groups of
more than one of these kinds can of course also be used. These acid groups have
the effect, in the nitrosamine compounds obtained, of rendering the said compounds
In some cases one such
sufficiently stable for the purposes of this invention.
group is sufficient but in others more are necessary. As a few instances of the
substituted amines which can be used I mention the following but these are merely
Ortho nitro aniline
examples and the invention is not restricted to their use.
nitro-toluidine CH,NO,NH, di chloro-aniline ClCINH„, and para nitro alpha-
naphthylamine.
Th
1 3 4
1 4 3
Sallami szemples of the annlication of the processes to the diazo

page_text: but as aforesaid other diazo-compounds may be used, and the conditions may be
varied in each case. The parts are by weight.
EXAMPLE 1. PRODUCTION OF A NEW NITROSAMINE IN THE FORM OF
SODIUM COMPOUND.
Prepare a ten per cent. solution of the diazo compound of para-nitroaniline in
the usual way using say about one hundred and thirty eight parts of para nitro-
aniline add this whilst thoroughly stirring to about eight thousand parts of hot
caustic soda solution (containing about 18 per cent. NaOH). Allow the mixture
to cool. The sodium salt of the nitrosamine separates out in the crystalline form.
Collect and recrystallize from about seven hundred parts of hot water. The
mother liquor may be treated with common salt to recover the nitrosamine
remaining in solution.
Instead of caustic soda, caustic potash or barium hydrate can be used in the
above example and the corresponding salts be obtained. The sodium salt can
also be converted into the salts with other metals by double decomposition.⚫
The above example describes a method of obtaining the nitrosamine salt as fine
crystals; it is however unnecessary in practice to prepare this crystalline form as
the compound is just as stable in the amorphous as in the crystalline state..
In the following example a mode of operating is described which gives the
nitrosamine salt in the less distinctly crystalline form.
EXAMPLE 2.
Run a solution of the diazo compound into cold, caustic soda lye (containing
about eighteen per cent. NaOH) taking sufficient of the said lye that the resulting
mixture is strongly alkaline. The nitrosamine salt separates out, owing to the
presence of excess of alkali, filter press and dry or preserve for use in the form of
paste. If necessary precipitate any of the salt remaining in the mother liquor
with common salt.
In both the foregoing examples the production of the new compound takes
place practically instantaneously. In any case it is easy to test whether the
operation is completed by mixing a portion of the mixture with a solution of beta-
naphthol in an excess of alkali and then if no azo dye be produced in the cold
the desired conversion is complete.
By this invention the further advantage is gained that it is unnecessary to use
pure para-nitro-aniline in order to obtain eventually a pure diazo solution. If in
the above examples the diazo compound from a crude para nitro aniline be used,
such as contains a considerable admixture of ortho and meta nitro aniline, then
these admixed bases will simultaneously be converted into their nitrosamine salts
which are more readily soluble in water than the para derivative and consequently
remain practically completely in the mother liquors. These ortho and meta
nitrosamine compounds can themselves be used in the aforesaid dyeing process.
By proceeding on the same principle as herein set forth and using certain
primary amines of the aforesaid chemical nature, salts of the corresponding nitros-
amines can be obtained. The details of the processes to be adopted must be
varied of course according to the solubility and other properties of the bodies
treated. In some cases where the nitrosamine compounds are very soluble and
can only be precipitated with difficulty it is preferable to prepare and use them in
the form of solutions.

page_text: about six per cent. real acid H.Cl.). The free nitrosamine separates at once.
Filter and wash with cold water. The free nitrosamine must not be allowed to
get dry but must be applied in the production of the diazo-compound in the form
of paste.
EXAMPLE 4.
The production of the free nitrosamine and its conversion into the diazo-
compound may often conveniently be effected in one operation.
Dissolve about ten parts of the nitrosamine salt in about two hundred and
fifty parts of water, pour the solution into about eighteen parts of hydrochloric
acid (thirty per cent. "HCI). A precipitate of the free nitrosamine is formed
which disappears as it is converted into the diazo compound. If any precipitate
remain undissolved test a portion thereof by treatment with cold dilute caustic
soda which gives a yellow solution with unchanged nitrosamine. If none be found
by this test or if the entire solution contains practically no precipitate the
operation may be regarded as completed.
To obtain the diazo-solution from the separated free nitrosamine suspend the
quantity corresponding to ten parts of the sodium salt in about two hundred and
fifty parts of water and proceed then in the manner hereinbefore described.
The operation proceeds the more rapidly if more acid be used. Increase of
temperature has a similar effect but it increases liability of the diazo-compound to
decomposition.
It is possible to accelerate the reaction to an important degree by working in
the presence of a small quantity of nitrous acid which can conveniently be secured
by adding say about one per cent. of sodium nitrite of the nitrosamine salt in the
manufacture thereof or it may be added to the solution during the operation of
conversion into the diazo-compound.
The conversion of the nitrosamine into the diazo compound can also be effected
on the fibre itself. Thus for instance my foreign correspondents have discovered
that a mixture of nitrosamine salt and certain phenols and amines and derivatives
thereof preferably such as are soluble in alkali, with an excess of alkali can be
prepared and transported without decomposition. If such a mixture suitably
prepared be printed on textile fabrics then on neutralizing the alkali the diazo-
compound is gradually formed but immediately combines with the component
present, developing the colour. The neutralizing and development of colour can
be effected by exposing the printed goods to the atmosphere or by treating in a
dilute acid (say acetic acid) bath. Warmth accelerates the action.
Datori the 21st October 1902
J. H. JOHNSON & Co.
The Manufacture and Production of New Compounds suited for Use
in the Preparation of Diazo Compounds, and their Application in
the Production of Dyes.
I, JAMES YATE JOHNSON of 47 Lincoln's Inn Fields in the County of
Middlesex Gentleman, do hereby declare the nature of this invention (which has
been communicated to me from abroad by The Badische Anilin and 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 :-
In the production of certain shades of colour by means of one well-known
process the dyer combines diazo-compounds with amines or phenols on or in the
presence of the fibre. As the diazo-compounds generally are an extremely unstable

page_text: class of bodies it is necessary that they should be prepared in the dyeing factory as
they cannot practically be transported. The preparation of the diazo compounds
for the purpose in question is frequently inconvenient or difficult as the best result
can only be attained by careful and accurate observance of certain narrowly
bounded conditions.
My foreign correspondents have discovered that the diazo compound of para-
nitro-aniline on. suitable treatment with an alkali even at ordinary temperature is
converted into the alkali salt of the isomeric nitrosamine compound, which is a
readily crystallizable compound that can easily be isolated and possesses con-
siderable stability. A solution of this product yields no dye even on standing
after mixing with a solution of sodium beta-naphtholate and an excess of alkali.
By treatment with one molecular proportion of an acid the alkali salt is
converted into the free nitrosamine which is less stable than the alkali salt but can
if desired be prepared and used in the form of paste. On treatment with a larger
proportion of acid preferably in the presence of a little nitrous acid, the new
nitrosamine is smoothly and readily reconverted into the diazo compound. Thus
by means of this invention it is possible to prepare a stable compound capable of
transport which can easily be converted into the diazo compound ready for use in
the aforesaid dyeing process.
The processes above described can also be applied to the production of similar
compounds from diazo compounds derived from such aromatic amido compounds as
contain one or more substituting acid groups such as one or more nitro groups two
or more halogens (in one benzene residue) with or without sulpho groups and the
like. Bodies containing acid groups of more than one of these kinds can of course
also be used. As a few instances of the substituted amines which can be used I
mention the following but these are merely examples and the invention is not
restricted to their use.
1 4 3
1 3 4
Ortho-nitro-aniline, nitro-toluidine CH,NO,NH₂ di-chloro-
aniline CICINH, para-nitro-alpha-naphthylamine, dinitrobenzidine, nitro-aniline-
sulpho and carboxylic acids and picramine acid.
The following examples will serve to illustrate the nature of the invention and
the manner in which it can be carried into practical effect, but the conditions may
be varied without departing from the nature of the invention. The parts are by
weight.
EXAMPLE 1. PRODUCTION OF A NEW NITROSAMINE IN THE
SODIUM COMPOUND.
FORM OF
Prepare a ten per cent. solution of the diazo compound of para-nitroaniline which
may be done in the usual way, using, say about one hundred and thirty eight parts
of para-nitroaniline. Add this, whilst thoroughly stirring, to about eight thousand
parts of caustic soda solution, heated to about sixty to seventy degrees centigrade
(containing about eighteen per cent. NaOH). Allow the mixture to cool. The
sodium salt of the nitrosamine separates out in the crystalline form. Collect and
recrystallize from about seven hundred parts of hot water. The mother liquor
may be treated with common salt to recover the nitrosamine salt remaining in
solution.
Caustic potash, carbonate of soda, carbonate of potash or barium hydrate can be
used in the above example instead of caustic soda when the corresponding salts will
be obtained. The sodium salt can also be converted into the salts of other metals
by double decomposition.
The above example is a method of obtaining the nitrosamine salt as fine crystals;
it is however unnecessary in practice to prepare this crystalline form as the
compound is just as stable in an amorphous or less crystalline state.
In the following example a mode of operating is described which gives the
nitrosamine salt in the less distinctly crystalline form.

page_text: EXAMPLE 2.
Run a solution of the diazo-compound into cold caustic soda-lye (containing
about eighteen per cent. NaOH) taking so much of the said lye that the resulting
mixture is still strongly alkaline. The nitrosamine salt separates out owing to the
presence of excess of alkali. Filter, press and dry or preserve for use in the form
of paste. If necessary precipitate with common salt any of the nitrosamine salt
remaining in the mother liquor.
In both the foregoing examples the production of the new compound takes place
practically instantaneously. In any case it is easy to test whether the operation is
completed by mixing a portion of the mixture with a solution of beta naphthol in
any excess of alkali and then if no azo dye be produced in the cold the desired
conversion is complete.
-
By this invention the further advantage is gained that it is unnecessary to use
pure para-nitro-aniline in order to eventually obtain a pure diazo solution. If in
the above examples the diazo-compound from a crude para-nitro-aniline be used,
such as contains a considerable admixture of ortho- and meta-nitro-aniline, then
these admixed bases will simultaneously be converted into their nitrosamine salts
which are more readily soluble in water than is the para-derivative and consequently
remain practically completely in the mother liquors. These ortho- and meta-
nitrosamine compounds can themselves be used in the aforesaid dyeing process.
By proceeding on the same principle as herein set forth and using certain
primary amines, of the aforesaid chemical nature, salts of the corresponding nitros-
amines can be obtained. The details of the processes to be adopted must be
varied of course according to the solubility and other properties of the bodies
treated. In some cases where the nitrosamine compounds are very soluble and can
only be precipitated with difficulty it is preferable to prepare and use them in the
form of solutions.
tod
Prepare a ten per cent. solution of para-dichloro-diazo-benzol-chloride which may
be done in the usual way from about one hundred and sixty parts of para-dichlor-
aniline, and stir well with about one thousand six hundred parts of caustic soda lye
(containing about thirty five per cent. NaOH) and eight hundred parts of ice. The
nitrosamine salt is rapidly formed. To isolate it, either add about six hundred
parts of caustic soda powder, or concentrate the solution by evaporation till
crystallization begins. In either case allow the solution to cool, collect the
nitrosamine salt by filtering, and dry, or if it be desired to preserve in the form of
paste mix it with the requisite quantity of common salt solution.
The conversion of the diazo compound into nitrosamine can also be effected by
the action of caustic potash, caustic lime, and the like, when the nitrosamine is
obtained in the form of the corresponding salts. Also the carbonates of soda and
potash can be used.
EXAMPLE 4. CONVERSION OF THE NITROSAMINE SALT INTO FREE PARA-
NITRO-PHENYL-NITROSAMINE.
Dissolve about ten parts of the nitrosamine salt (obtained as described in
Examples 1 & 2) in about two hundred and fifty parts of cold water, add about
thirty parts of dilute hydrochloric acid (containing about six per cent. real
acid HCI). The free nitrosamine separates at once.
Filter and wash with cold
water. The free nitrosamine must not be allowed to get dry but must be employed
in the production of the diazo-compound in the form of paste.
13

page_text: The production of the free nitrosamine and its conversion into the diazo compound
may often conveniently be effected in one operation.
Dissolve about ten parts of the nitrosamine salt in about two hundred and fifty
parts of water; pour the solution into about eighteen parts of hydrochloric acid
(thirty per cent. HCl). A precipitate of the free uitrosamine is formed which
disappears as it is converted into the diazo compound. If any precipitate remains
undissolved test a portion thereof by treatment with say cold dilute caustic soda
which gives a yellow solution with unchanged nitrosamine.
If none be found by this test or if the entire solution contains practically no
precipitate the operation may be regarded as finished.
To obtain the diazo solution from the separated free nitrosamine suspend the
quantity corresponding to ten parts of the sodium salt in about two hundred and
fifty parts of water and proceed then in the manner hereinbefore described.
The operation proceeds more rapidly if more acid be used. Increase of tem-
perature has a similar effect but it increases the liability of the diazo-compound to
decomposition.
It is possible to accelerate the reaction to an important degree by working in the
presence of a small quantity of nitrous acid which can conveniently be secured by
adding say about one per cent. of sodium nitrite to the nitrosamine salt in the
manufacture thereof or it may be added to the solution during the operation of
conversion into the diazo compound.
The conversion of the nitrosamine into the diazo compound can also be effected
on the fibre itself. Thus for instance my foreign correspondents have discovered
that a mixture of nitrosamine salt and certain phenols and amines and derivatives
thereof preferably such as are soluble in alkali, with an excess of alkali can be
prepared and transported in the usual way without decomposition. If such a
mixture suitably prepared, be printed on textile fabrics then on neutralizing the
alkali the diazo-compound is gradually formed but immediately combines with the
component present developing the colour.
This neutralizing and the development of the colour can be effected by exposing
the printed goods to the atmosphere or by treating in a dilute acid (say acetic acid)
bath. Warmth accelerates the action.
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 manufacture of new nitrosamine compounds by treating with an alkali
such diazo-compounds as are derived from aromatic amido-compounds containing
one or more substituting acid groups such as one or more nitro groups, two or
more halogens (in one benzene residue) with or without sulpho groups, and the
like, all substantially as hereinbefore described.
2. The manufacture of a new nitrosamine compound from the diazo compound of
para-nitro aniline in the manners described in the Examples 1 and 2.
3. The manufacture of a new nitrosamine compound from the diazo compound of
dichloroaniline in the manner described in Example 3.
4. The conversion of the new nitrosamine compounds herein described and
claimed in the first claiming clause into diazo-compounds by treatment with excess
of an acid substantially as herein before described.
5. The conversion of the new nitrosamine compounds herein described and claimed
in the first claiming clause into diazo compounds by treatment with excess of an
acid and in the presence of a small quantity of nitrous acid substantially as
herein before described.

page_text: 6. The new articles of manufacture, namely the nitrosamines compounds such as
can be obtained as herein before described and claimed and their use in the
production of azo dyes on the fibre.
01 of
1001
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, W.C., Agents.