The Manufacture or Production of Condensation Products from Amines or Derivatives thereof by Oxidation in Alkaline Solution.
Year: 1893

page_text: Date of Application, 5th Sept., 1893
Complete Specification Left, 2nd June, 1894-Accepted, 7th July, 1894
PROVISIONAL SPECIFICATION.
[Communicated from abroad by THE FARBENFABRIKEN vormals FRIEDRICH
BAYER & Co., of Elberfeld, in the Empire of Germany.]
The Manufacture or Production of Condensation Products from
Amines or Derivatives thereof by Oxidation in Alkaline
Solution.
I HENRY EDWARD NEWTON of The Office for Patents, 6 Bream's Buildings,
Chancery Lane in the County of London, Patent Agent, do hereby declare the
nature of this invention to be as follows:-
It is known that azoxy and azo bodies are obtained in small amounts by oxidising
aniline with potassium permanganate (see Glaser in the Annalen der Chemie und
Pharmacie, volume 142, page 364). Limpricht (see Berichte der Deutschen
Chemischen Gesellschaft, volume 18, page 1421) succeeded in producing ortho,
meta, and para azoxybenzene sulpho acids (also in small amounts) by oxidising
salts of the corresponding aniline sulpho acids with potassium permanganate.
Bamberger and Meimberg (see Berichte der Deutschen Chemischen Gesellschaft,
volume 26, page 496) have mentioned that azo benzene is formed as by-product
on the oxidation of aniline with potassium permanganate, or potassium ferri-
cyanide.
These reactions, however, do not proceed in an even or regular manner, and the
said products are obtained in such small quantities as often to scarcely deserve
notice.
My foreign correspondents have described in the Specification of the English
Letters Patent No. 19061, dated 4th November 1891, that dehydrothiopara-
toluidine sulpho acid, dehydrothiometaxylidine sulpho acid, and dehydrothiopseudo-
cumidine sulpho acid, are converted into yellow dye stuffs by oxidising them, in
alkaline solution, with hypochlorites, hypobromites, potassium ferricyanide, lead
dioxide, or other oxidising agents. The oxidation can also be effected, by means of
potassium permanganate, in an alkaline solution. My foreign correspondents
assume that azo or azoxy products are formed in the last named processes.
My foreign correspondents have now found that other amines or diamines, nitro
amines, sulpho or carboxylic derivatives, or other derivatives thereof, when treated
with so-called alkaline oxidising agents (such as hypochlorites, hypobromites,
potassium permanganate, potassium ferricyanide, lead dioxide, or the like) are
readily converted into condensation products, which probably are azo or azoxy
compounds. These products are of special value, as they can be employed for
preparing other chemical compounds or dye stuffs therefrom.
The process is illustrated by the following example, the parts being by weight.

page_text: which is theoretically necessary for oxidation, of a solution of sodium hypochlorite,
the mass is allowed to stand at ordinary temperature, with sufficient stirring, until
a test portion taken out, after diazotising with muriatic acid and sodium nitrite,
does not yield a coloring matter with naphthol sulpho acids. If this stage be
arrived at, the product formed is filtered off and washed.
It is scarcely soluble in water, soluble with difficulty in alcohol, and dissolves
with greater readiness in ether, acetone, and chloroform. It is dissolved by con-
centrated sulphuric acid, yielding a brown color. On mixing it with dilute alkali
lye, and subsequently reducing it at low temperature by means of potassium
sulphhydrate, or alkaline solutions of stannous chloride, the liquid assumes, after a
few minutes, a deep bluish color, which, after standing for a longer period (or
rapidly on heating), changes at first into green, and subsequently into yellowish
brown.
The para nitro aniline employed in the above example, can be replaced by ortho
or meta nitro aniline, nitrotoluidine, nitroxylidine, sulpho or carboxylic derivatives
thereof, alpha or beta naphthylamine, or nitro derivatives or sulpho derivatives, or
other derivatives thereof, amidophenols or amido naphthols, or amidophenolethers,
or amido naphtholethers, or sulpho or carboxylic derivatives thereof, benzidine or
its analogues or homologues, or nitro or sulpho derivatives thereof, diamido stilbene,
or sulpho derivatives thereof, benzidine sulphone or its analogues, or nitro or sulpho
derivatives thereof. The process, however, is not restricted to the employment of
the said amido compounds, as similar amines or diamines, or substitution derivatives
thereof, can likewise be used. Products are obtained in this manner which very
probably are azo or azoxy compounds.
The method of manufacture is not restricted to the directions given in the above
example, as these can be varied. For instance, in place of hypochlorites,―hypo-
bromites, potassium permanganate, potassium ferricyanide, lead dioxide or the like,
can also be used. The process can also be effected by introducing chlorine, or adding
bromine, to the alkaline solution of the respective amido product. Such or similar
modifications do not alter the nature of this invention, which in general relates to
the production of condensation products (which probably are azo or azoxy
compounds), by oxidising amines, diamines, or derivatives thereof, in alkaline
solution.
Dated this 5th day of September 1893.
NEWTON & SON,
Agents for the Applicant.
The Manufacture or Production of Condensation Products from
Amines or Derivatives thereof by Oxidation in Alkaline
Solution.
I, HENRY EDWARD NEWTON, of The Office for Patents, 6 Bream's Buildings,
Chancery Lane, in the County of London, Patent Agent, 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 :-
It is known, that several azoxy and azo compounds have been obtained by
oxidising aromatic amines.
These actions, however, do not proceed in an even or regular manner, and the
said products are obtained in such small quantities as often to scarcely deserve
notice.
My foreign correspondents have described in the Specification of the English
Letters Patent dated 4th November 1891, No. 19061, the manner in which
dehydrothio paratoluidinesulphonic acid, dehydrothiometaxylidinesulphonic acid,

page_text: and debydrothiopseudo cumidine sulphonic acid, are converted into yellow dyestuffs
by oxidising them in alkaline solution with hypochlorites, hypobromites, potassium
ferricyanide, or other oxidising agents. The oxidation can also be effected by
means of potassium permanganate in an alkaline solution. My foreign corre-
spondents assume, that azo or azoxy products are also formed in the last named
processes.
My foreign correspondents have now found that, as a general rule, aromatic
amido compounds containing acid radicles combined with the benzene nucleus, can
be oxidised by alkaline oxidising agents in an even or regular manner, forming
condensation products which belong to the group of azo or azoxy compounds. My
foreign correspondents assume that the said amido compounds containing acid
radicles in the benzene nucleus, can be readily oxidised owing to the fact that the
amido group is influenced by the acid group; that, for instance, the basic nature
of the amido group contained in para-nitraniline, is weakened by the nitro group.
This becomes evident on taking into account the fact that, for instance, when
oxidised with the aid of hypochlorites or the like, paranitraniline is almost entirely
converted into para dinitrazoxybenzene or paradinitroazobenzene.
Other amido or diamido compounds containing acid groups, such as the nitro-
group, sulphonic group, or the like, shew the same behaviour when acted on by
alkaline oxidising agents. In order to effect the said oxidation, hypochlorites,
hypobromites, potassium permanganate, potassium ferricyanide, ammonium per-
sulphate, or other agents acting in the same or a similar manner, can be used.
Some of the condensation products thus obtained are of special value, as they
can be used for preparing other compounds or dyestuffs.
The process is illustrated by the following examples, the parts being by weight.
An excess of sodium hypochlorite having been added to finely divided para-
nitraniline mixed with dilute soda lye, the mixture is allowed to stand during
several hours. When a test portion which has been diazotised with muriatic acid
aud sodium nitrite yields but a very slight quantity of a colouring matter with
naphtholsulphonic acids, the product is filtered off and washed with a small quantity.
of water. In order to remove any unaltered para nitraniline, the product is
subsequently digested with dilute muriatic acid. The condensation product thus
obtained varies in colour from reddish brown to brownish black.
It is scarcely soluble in water, and with difficulty in alcohol, but dissolves with
greater readiness in acetone and chloroform. It is dissolved by concentrated sulphuric
acid, yielding a brown coloured solution. On allowing its solutions in chloroform
to evaporate, reddish-brown crystals, exhibiting a bluish reflex, are deposited,
which melt at 221 degrees centigrade. If it is suspended in dilute soda-lye, and
subsequently reduced by means of potassium sulphhydrate or alkaline solutions of
stannous chloride, the liquid soon assumes a deep-blue colour, which changes first
into green, then into yellowish brown, on allowing the mixture to stand, this change
being effected within a shorter time if heat be applied. On boiling its alcoholic
solution with ammonium hydrosulphite, and subsequently adding soda-lye, a deep
blue colour appears, owing to the formation of a nitrolic acid, an action characteristic
of nitrazo compounds (see Janovsky and Erb, Berichte der Deutschen Chemischen
Gesellschaft, volume 18, page 1136). When further subjected to the action of
weak reducing agents (such as potassium sulphhydrate, ammonium sulphide) the
nitro-groups are totally reduced, an amido compound being thus formed which may
be diazotised and combined with dyestuff components, and thus converted into
substantive azo colouring matters. On using more energetic reducing agents,
paraphenylene diamine is finally obtained.

page_text: My foreign correspondents, therefore, assume, that the condensation product
obtainable as described in the above Example A, is the paradinitrazoxybenzene
represented by the formula :-
The process takes place in a manner analogous to that described in the above
Example A, if, instead of the paranitraniline used therein, corresponding quantities
of orthonitraniline, meta-nitraniline, or homologues thereof, are used.
As above mentioned, sulphonic acids of aromatic amido or diamido compounds
can also be used in the said process. For instance, benzidine metamonosulphonic
acid, when oxidised in presence of alkali by means of hypochlorites or the like,
according to the directions given in the above Example A, yields a condensation
product which for the most part separates from the liquid. This condensation
product possesses a brown colour, and after being converted into the sodium salt,
readily dissolves in hot water. It is dissolved by concentrated sulphuric acid,
affording a black-violet coloured solution, and is capable of dyeing unmordanted
cotton, yellowish orange shades being thus produced. When fixed on cotton, it
can be diazotised, and subsequently combined with dyestuff components (so-called
developers). For instance, on using betanaphthol as developer, a red shade is
obtained, toluylenediamine yielding a brown shade. According to the researches
of my foreign correspondents, the said condensation product can also be directly
diazotised, and the diazo product thus obtained can be combined with dyestuff
components to form dyestuffs. This condensation product is probably either an
azoxy or azo compound, and if it be an azoxy product, its composition is probably
represented by the formula :-—
As this formula indicates, my foreign correspondents assume that the amido
groups in the benzene nuclei containing the sulphonic groups, are concerned in the
formation of the azoxy group.
An analogous result is obtained, if other sulphonic acids of benzidine, or
sulphonic acids of homologues thereof, are used in place of benzidine-metamono- 3
sulphonic acid.
According to the researches of my foreign correspondents, diamidostilbene
disulphonic acid can also be used in the process hereinbefore defined, and may be
oxidised, for instance, in the manner illustrated by the following example.

page_text: OXIDATION OF
DIAMIDOSTILDENEVIOUS
AVID
The concentrated solution of diamidostilbenedisulphonic acid in an excess of alkali.
is gradually mixed with ammonium persulphate, until a slight excess of the
oxidising agent is distinguishable, even after an interval of about two hours. Care.
must be taken that the liquid remains alkaline during the whole operation. The
end of the oxidation can easily be recognised by the fact that when a drop is placed
on filter paper, it forms a uniform orange-coloured spot. The dye-stuff which.
separates is filtered off. A further slight quantity of the colouring matter can be
obtained by adding common salt to the filtrate, and filtering off the dye-stuff thus.
precipitated.
This oxidation, which can also be carried out with the aid of hypochlorites (such.
as sodium hypochlorite or the like), yields a reddish-brown condensation product.
This, when dry, exhibits metallic lustre. It is dissolved by concentrated sulphuric
acid, affording a deep-blue coloured solution. Its alkaline salts dissolve in water,
affording a reddish-brown coloured solution. Mineral acids separate from solutions.
of the sodium salt of this condensation product, the sulphonic acid in the form of
blackish-brown flakes. It produces yellowish orange shades on unmordanted cotton,.
profitably when dyeing takes place in baths containing common salt.
The product obtained by oxidising diamidostilbene disulphonic acid contains free
amido groups, and can be diazotised and coupled with dye-stuff components. It is
reconverted into diamidostilbenedisulphonic acid, when it is reduced by means of
energetic reducing agents.
Owing to the fact that the last-named condensation product contains free amido.
groups, and that it is transformed again into diamidostilbenedisulphonic acid, my
foreign correspondents assume that two or more molecules of diamidostilbene
disulphonic acid are connected in the said process, an azoxy or azo product being thus.
formed. On the assumption that two molecules are combined, and that the
resulting product is an azoxy compound, the said condensation product can be.
represented by the following formula :-
The method of carrying out the oxidation hereinbefore defined and illustrated by
the two examples A and B, is not restricted to the directions given in the above-
examples, as these can be varied. For instance, in place of hypochlorites or
5 ammonium persulphate, hypobromites, potassium permanganate, potassium ferri-
cyanide, or other alkaline oxidising agents producing the same result, can be used.
The process can also be effected by introducing chlorine or bromine into the
alkaline liquid in which the amido compound is dissolved or suspended. Such.
or similar modifications do not alter the nature of this invention, which in general
O relates to the production of condensation products from aromatic amines or diamines.

page_text: containing acid groups in the benzene nuclei, by oxidising them in presence of
alkali.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed (as communicated to me from
abroad), I declare that what I claim is :-
1. The process for producing condensation products, which process consists in
subjecting aromatic amines or diamines containing acid groups in the benzene nuclei,
such as orthonitraniline, meta nitraniline, para nitraniline, or homologues thereof,
sulphonic acids of benzidine or of homologues thereof, diamidostilbenedisulphonic
acid, or the like, to an oxidation, when dissolved or suspended in an alkaline
solution.
2. As new products of manufacture, the new condensation products produced by
the processes hereinbefore described, or by any other means affording the same
result.
ML
1001
NEWTON & SON,
Agents for the Applicant.