Improvements in the Manufacture of Indigo and Substituted Indigoes and Intermediate Products.
Year: 1899

page_text: PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Indigo and Substituted
Indigoes and Intermediate Products.
A communication from CHEMISCHE FABRIK VON HEYDEN, of Radebeul, near
Dresden, Saxony, Manufacturers.
I, JOHN CLAYTON MEWBURN, of the Firm of J. C. Mewburn and Ellis, of 55
and 56, Chancery Lane, in the County of London, Chartered Patent Agents, do
hereby declare the nature of this invention to be as follows:-
This invention has reference to the manufacture of indigo and substituted
indigoes and intermediate products,
Indigo and substituted indigoes result, as is known, from the treatment of
o-nitro-benzaldehyde and its substitution products with acetone and alkali.
My foreign correspondents have discovered that o-nitrobenzaldehyde may
be made to at once combine with fatty and aromatic amines, their substitution
products, and their oxy-, carbon-, and sulpho- derivatives, to form condensation
products and simultaneously water, of which condensation products those in
particular which are soluble in water will at once form indigo on addition of
acetone and alkali. As in the employment of the o-nitrobenzaldehyde for the
production of indigo in the ordinary manner ortho-nitro-phenyl-lacto-methyl-
ketone results as an intermediate product, so in the new method herein described
is there obtained as an intermediate product the condensation product of this
ketone with the particular amine in question.
The new method has many advantages over the known process; amongst others
may be mentioned the fact that it is possible according to this invention to
work with much smaller quantities of acetone, and further that it is not neces-
sary to employ pure o-nitro-benzaldehyde as the raw product, but mixtures
which contain same may be used.
EXAMPLE I.
a). 151 parts by weight of o-nitro-benzaldehyde are introduced into a solu-
tion of 380 parts by weight of naphthionate of soda (of 67%) in 3000 parts
water, and heated, while stirring, on the water bath for several hours at 50°
to 60° C., the nitro-benzaldehyde being thus dissolved. After cooling, the
yellow solution stiffens to a thick pasty mass of o-nitro-benzylidene-naphthionate
of soda, and which, for the sake of convenience, I refer to under that term.
b). 151 parts by weight of o-nitro-benzaldehyde are dissolved in 800 parts
by weight of alcohol and run into a solution of 380 parts naphthionate of soda
(of 67%) in 3000 parts water. After a short time small yellow flakes begin to
separate out, and after 5 or 6 hours the mass, which during the time has been
well stirred up, stiffens to a paste of o-nitro-benzylidene-naphthionate of soda.
c) 151 parts by weight of o-nitro-benzaldehyde are dissolved in 800 parts of
toluol and well stirred up with a solution of 380 parts naphthionate of soda
(of 67%) in 3000 parts water. After a short time small yellow flakes begin to

page_text: separate out and after 5 to 6 hours intimate stirring, the mass stiffens to a thick
paste of o-nitro-benzylidene-naphthionate of soda.
If no pure o-nitro-benzaldehyde be available as the raw product, and more or
less impure o-nitro-benzaldehyde is employed, the impurities may be readily
removed by for example filtering off the impurities from the obtained solutions
of the condensation products before cooling i.e. before the condensation products
crystallize out; or by removing the impurities by means of extracting media, or
in any other usual way. The o-nitro-benzaldehyde can be distilled off from the
condensation products so purified, by simply treating them with steam. This
splitting off of the nitrobenzaldehyde is hastened by the addition of acids or
substances having an alkaline reaction. Such addition is necessary when the
condensation product contains a base, for example aniline, which is volatile
with steam.
Some of the condensation products so obtained have already been produced
in another way, namely by the oxidation of corresponding o-nitrobenzyl com-
pounds as described in German Patent Specifications 91503, 92084 and 93539.
According to one part of the present invention the condensation products of
o-nitrobenzaldehyde are transformed by treatment with acetone in alkaline solu-
tion into o-nitro-phenyl-lacto-methyl-ketone, and thence into indigo. My corre-
spondents may proceed for example as follows:
EXAMPLE II.
-
378 parts by weight of o-nitro-benzylidene-naphthionate of soda are heated
with 1200 parts water and 60 parts acetone to 30° to 40° C. in a closed vessel.
230 to 250 parts of a 1% soda lye is allowed to run slowly in while
stirring, and the mixture finally heated for several hours to complete the opera-
tion. The completion of the operation will be indicated by the commencement
of formation of indigo. The contents of the vessel will now be represented by
an aqueous solution of the sodium salt of the condensation product of o-nitro-
phenyl-lacto-methyl-ketone and naphthionic acid, from which the o-nitro-
phenyl-lacto-methyl-ketone can be obtained by treatment with acids and extract-
ing media (if desired).
These condensation products of o-nitro-phenyl-lacto-methyl-ketone with
naphthionic acid or other ammonia derivatives, are adapted for the production
of indigo upon the fibre, especially in printing, since they form indigo direct
under the action of alkali. If it be desired to transform the condensation pro-
ducts of o-nitrobenzaldehyde and ammonia derivatives direct into indigo, more
alkali must be used than that specified in the above example. The procedure
may then be as follows:-
EXAMPLE III.
378 parts by weight of o-nitrobenzylidene-naphthionate of soda are heated with
1200 parts water and 60 parts acetone to 30°-40° C. in a preferably closed vessel
provided with stirring gear. While the contents of the vessel are well stirred
700 parts of a 1% soda lye are run slowly in, and finally heated until the
formation of indigo is finished; the indigo formed is then filtered off, washed
and dried.
It is not necessary to employ ready formed o-nitro-benzylidene-naphthionate
of soda; o-nitrobenzaldehyde may be mixed first with acetone and then with
naphthionate of soda; or naphthionate of soda may be first mixed with acetone
and then with the aldehyde. In all cases the intermediate formation of the
intermediate product occurs. Instead of the naphthionic acid any other of the
above named ammonia derivatives which may be desired can be employed.
It is naturally a matter of indifference whether the intermediate products
employed in the present invention and resulting from o-nitro-benzaldehyde and
ammonia derivatives are produced from pure or crude o-nitro-benzaldehye, or
by the oxidation of the corresponding nitro-benzyl products or prepared in other
WAYS

page_text: The order of sequence in which the o-nitro-benzaldehyde or its substitution
product, the acetone, and the ammonia derivative are brought together, does
not appear to be of any consequence.
If, instead of the o-nitro-benzaldehyde products referred to, substituted pro-
ducts, for example chlorinated products-be employed, the corresponding sub-
stituted, for example, chlorinated- ortho-nitro-phenyl-lacto-methyl-ketones,
indigoes and intermediate products will be obtained.
The conditions of proportions and temperature specified in the examples can
naturally be varied without departing from the substance of this invention.
These condensation products of o-nitro-phenyl-lacto-methyl-ketone and
ammonia derivatives, adapted for the production of indigo shades upon the
fibre, may be also produced by treating o-nitro-phenyl-lacto-methyl-ketone manu-
factured in the ordinary way, with ammonia or ammonia derivatives.
O-nitro-phenyl-lacto-methyl-ketone dissolves in dilute aqueous ammonia solu-
tion to a clear yellow liquid, which may be filtered off from impurities of the
ketone, and indigo separates out from this liquid in presence of excess of alkali
or ammonia. Instead of ammonia, substituted ammonia may be employed, for
example fatty and aromatic amines, their substitution products, their oxy-
derivatives and their carbon- and sulpho- derivatives. For example:-
EXAMPLE IV.
209 parts by weight o-nitrophenyl-lacto-methyl-ketone are heated, while
stirring, with a solution of 380 parts by weight naphthionate of soda (of 67%)
in 2000 parts water, to about 60° C. If crude o-nitro-phenyl-lacto-methyl-
ketone has been used as the raw product, the solution is filtered off from the
undissolved impurities. The solution can be used direct for indigo printing.
Rendered alkaline, indigo separates out from the solution.
As ammonia compounds which are especially suitable for the purposes of this
invention the following may be mentioned: fatty and aromatic amines, their
substitution products, their oxy-derivatives, the salts of their carbo- and sulpho-
acids; more especially methylamine, aniline, toluidine, benzylamine, aniline-
sulphonic salts, toluidine-sulphonic salts, xylidine sulphonic salts, benzidine,
naphthylamine and their sulphonic salts, salts of amido-benzoic acid and amido-
salicylic acid.
T
1
Improvements in the Manufacture of Indigo and Substituted
Indigoes and Intermediate Products.
A communication from CHEMISCHE FABRIK VON HEYDEN, of Radebeul, near
Dresden, Saxony, Manufacturers.
I, JOHN CLAYTON MEWBURN, of the Firm of J. C. Mewburn and Ellis, of 55
and 50, Chancery Lane, in the County of London, Chartered Patent Agents, do
hereby declare the nature of this invention and in what manner the same is to

page_text: be performed, to be particularly described and ascertained in and by the follow-
ing statement:-
This invention has reference to the manufacture of indigo and substituted
indigoes and intermediate products.
Indigo and substituted indigoes result, as is known, from the treatment of
o-nitro-benzaldehyde and its substitution products with acetone and alkali.
My foreign correspondents have discovered that o-nitro-benzaldehyde may
be made to at once combine with fatty and aromatic amines, their substitution
products, and their oxy-, carbon-, and sulpho derivatives, to form condensation
products and simultaneously water, of which condensation products those in
particular which are soluble in water will at once form indigo on addition of
acetone and alkali. As in the employment of the o-nitrobenzaldehyde for the
production of indigo in the ordinary manner ortho-nitro-phenyl-lacto-methyl-
ketone results as an intermediate product, so in the new method herein described
is there obtained as an intermediate product the condensation product of this
ketone with the particular amine in question.
The new method has many advantages over the known process; amongst others
may be mentioned the fact that it is possible according to this invention to
work with much smaller quantities of acetone, and further that it is not neces-
sary to employ pure o-nitro-benzaldehyde as the raw product, but mixtures
which contain same may be used.
EXAMPLE I.
a). 151 parts by weight of o-nitro-benzaldehyde are introduced into a solu-
tion of 380 parts by weight of naphthionate of soda (of 67%) in 3000 parts
water, and heated, while stirring, on the water bath for several hours at 50
to 60° C., the nitro-benzaldehyde being thus dissolved. After cooling, the
yellow solution stiffens to a thick pasty mass of o-nitro-benzylidene-naphthionate
of soda, and which, for the sake of convenience, I refer to under that term.
b). 151 parts by weight of o-nitro-benzaldehyde are dissolved in 800 parts
by weight of alcohol and run into a solution of 380 parts naphthionate of soda
(of 67%) in 3000 parts water. After a short time small yellow flakes begin to
separate out, and after 5 or 6 hours the mass, which during the time has been
well stirned up, stiffens to a paste of nitro-benzylidene-naphthionate of soda.
c) 151 parts by weight of o-nitro-benzaldehyde are dissolved in 800 parts of
toluol and well stirred up with a solution of 380 parts naphthionate of soda
(of 67%) in 3000 parts water. After a short time small yellow flakes begin to
separate out and after 5 to 6 hours intimate stirring, the mass stiffens to a thick
paste of o-nitro-benzylidene-naphthionate of soda.
If no pure o-nitro-benzaldehyde be available as the raw product, and more or
less impure o-nitro-benzaldehyde is employed, the impurities may be readily
removed by for example filtering off the impurities from the obtained solutions
of the condensation products before cooling i.e. before the condensation products
crystallize out; or by removing the impurities by means of extracting media, or
in any other usual way. The o-nitro-benzaldehyde can be distilled off from the
condensation products so purified, by simply treating them with steam. This
splitting off of the nitrobenzaldehyde is hastened by the addition of acids or
substances having an alkaline reaction. Such addition is necessary when the
condensation product contains a base, for example aniline, which is volatile
with steam.
Some of the condensation products so obtained have already been produced
in another way, namely, by the oxidation of corresponding o-nitrobenzyl com-
pounds as described in German Patent Specifications 91503, 92084 and 93539.
According to one part of the present invention the condensation products of
o-nitrobenzaldehyde are transformed by treatment with acetone in alkaline solu-
tion into o-nitro-phenyl-lacto-methyl-ketone, and thence into indigo. My corre-
spondents may proceed for example as follows;-

page_text: EXAMPLE II.
378 parts by weight of o-nitro-benzylidene-naphthionate of soda are heated
with 1200 parts water and 60 parts acetone to 30° to 40° C. in a closed vessel:
230 to 250 parts of a 1%, soda lye is allowed to run slowly in while
stirring, and the mixture finally heated for several hours to complete the opera-
tion. The completion of the operation will be indicated by the commencement
of formation of indigo. The contents of the vessel will now be represented by
an aqueous solution of the sodium salt of the condensation product of o-nitro-
phenyl-lacto-methyl-ketone and naphthionic acid, from which the o-nitro-
phenyl-lacto-methyl-ketone can be obtained by treatment with acids and extract-
ing media (if desired).
These condensation products of o-nitro-phenyl-lacto-methyl-ketone with
naphthionic acid, or other ammonia derivatives, are adapted for the production
of indigo upon the fibre, especially in printing, since they form indigo direct
under the action of alkali. If it be desired to transform the condensation pro-
ducts of o-nitrobenzaldehyde and ammonia derivatives direct into indigo, more
alkali must be used than that specified in the above example. The proceduré
may then be as follows:-
EXAMPLE III.
378 parts by weight of o-nitrobenzylidene-naphthionate of soda.are heated with
1200 parts water and 60 parts acetone to 30° to 40° C., in a preferably closed vessel
provided with stirring gear. While the contents of the vessel are well stirred
700 parts of a 1% soda are run slowly in, and finally heated until the
formation of indigo is finished; the indigo formed is then filtered off, washed
and dried.
It is not necessary to employ ready formed o-nitro-benzylidene-naphthionate
of soda; o-nitrobenzaldehyde may be mixed first with acetone and then with
naphthionate of soda; or naphthionate of soda may be first mixed with acetone
and then with the aldehyde. In all cases the intermediate formation of the
intermediate product occurs. Instead of the naphthionic acid any other of the
above named ammonia derivatives which may be desired can be employed.
It is naturally a matter of indifference whether the intermediate products
employed in the present invention and resulting from o-nitro-benzaldehyde and
ammonia derivatives are produced from pure or crude o-nitro-benzaldehyde, or
by the oxidation of the corresponding nitro-benzyl products or prepared in other
ways.
The order of sequence in which the o-nitro-benzaldehyde or its substitution
product, the acetone, and the ammonia derivative are brought together, does
not appear to be of any consequence.
If, instead of the o-nitro-benzaldehyde products referred to, substituted pro-
ducts, for example chlorinated products-be employed, the corresponding sub-
stituted, for example, chlorinated- ortho-nitro-phenyl-lacto-methyl-ketones,
indigoes and intermediate products will be obtained.
The conditions of proportions and temperature specified in the examples can
naturally be varied without departing from the substance of this invention.
These condensation products of o-nitro-phenyl-lacto-methyl-ketone and
ammonia derivatives adapted for the production of indigo shades upon the
fibre, may be also produced by treating o-nitro-phenyl-lacto-methyl-ketone manu-
factured in the ordinary way, with ammonia or ammonia derivatives.
O-nitro-phenyl-lacto-methyl-ketone dissolves in dilute aqueous ammonia solu-
tion to a clear yellow liquid, which may be filtered off from impurities of the
ketone, and indigo separates out from this liquid in presence of excess of alkali
or ammonia. Instead of ammonia, substituted ammonia may be employed, for
example fatty and aromatic amines, their substitution products, their oxy-
derivatives and their carbon- and sulpho- derivatives. For example:

page_text: EXAMPLE IV.
209 parts by weight o-nitrophenyl-lacto-methyl-ketone are heated, while
stirring, with a solution of 730 parts by weight naphthionate of soda (of 67%)
in 2000 parts water, to about 60° C. The excess of napthionate of soda in this
example is for the better result of reaction. If crude o-nitro-phenyl-lacto-methyl-
ketone has been used as the raw product, the solution is filtered off from the
undissolved impurities. The solution can be used direct for indigo printing.
Rendered alkaline, indigo separates out from the solution. The solution can
be evaporated, best in vacuo. The resulting dry salt is readily soluble in water
and may be used for printing and dyeing.
As ammonia compounds which are especially suitable for the purposes of this
invention the following may be mentioned: fatty and aromatic amines, their
substitution products, their oxy-derivatives, the salts of their carbo- and sulpho-
acids, aniline-sulphonic salts, toluidinesulphonic salts, xylidine-sulphonic salts,
naphthylamine sulphonic salts, salts of amido-benzoic acid and amido-salicylic
acid.
Having now particularly described and ascertained the nature of the said
invention, as communicated to me, and in what manner the same is to be per-
formed, I declare that what I claim is:-
1. Method of producing indigo and substituted indigo, thus characterised,
First, that o-nitro-benzaldehyde and its substitution products, with or without
a solvent, are brought together with ammonia derivatives, and
Secondly, that the products so resulting, whether produced in this way or in
another way, are treated with acetone and alkali, for their transformation into
indigo, the order of sequence in which the three reagents,-nitro-benzaldehyde,
acetone, amine, are brought together, being a matter of indifference.
2. A special carrying out of the method characterised in Claim 1, with the
following ammonia derivatives, fatty and aromatic amines, their substitution
products, their oxy-derivatives, the salts of their carbo- and sulpho- acids.
3. Special carrying out of the method characterised in Claims 1 and 2 with
the following ammonia derivatives, aniline-sulphonic salts, toluidine, -sulphonic.
salts, xylidine sulphonic salts, naphthylamin-sulphonic salts, salts of amido-
benzoic acid and of amido salicylic acid.
4. The method specified in Claim 1 interrupted after stage 1, that is to say
carried out only up to the formation of the products from ammonia derivatives
and o-nitrobenzaldehydes, and with employment of the salts of aromatic amido
acids as ammonia derivatives.
5. The application of the method characterised in Claim 4 to mixtures con-
taining nitrobenzaldehyde for the purpose of separating this aldehyde from
foreign matters, and regenerating the aldehyde by treating the condensation
products with steam, if necessary or desirable, with addition of acids or sub-
stances having an alkaline reaction.
6. The interruption of the process specified in Claim 1, in the middle of
stage 2, that is to say, before the formation of indigo, but after the formation
of the condensation products of the nitro-phenyl-lacto-methyl-ketones with the
ammonia derivatives.
7. The production of o-nitro-phenyl-lacto-methyl-ketones characterised by
treating the reaction mass, after interrupting the process as specified in Claim 6,
with mineral acid.
8. Production of the product obtainable according to Claim 6, by treating
ready formed nitrophenyl-lacto-methyl-ketones with ammonia and the ammonia
derivatives specified in Claims 1 to 3.
9. The employment of the products obtained according to Claims and 8 for
dyeing and printing.
10. The new product consisting of a condensation product from ortho-nitro-

page_text: phenyl-lacto-methyl-ketone with a salt of an aromatic amido acid forming a
powder readily soluble in water which yields indigo on addition of alkaline
reagents.
Dated thin 15th day of 1000
J. C. MEWBURN & ELLIS,
55 and 56, Chancery Lane, London, Chartered Patent Agents.