Manufacture of Diamido-dibenzimidazols and Coloring Matters therefrom.
Year: 1893

page_text: Date of Application, 18th Aug., 1893
Complete Specification Left, 18th May, 1894-Accepted, 18th Aug.,
1894
[Communicated from abroad by THE FARBWERKE vormals MEISTER LUCIUS
AND BRUNING, of Hoechst a/ Main, in the Empire of Germany, Chemical
Manufacturers.]
Manufacture of Diamido-dibenzimidazols and Coloring Matters
therefrom.
I, OLIVER IMRAY of No. 28 Southampton Buildings, Chancery Lane, in the
County of London, Chartered Patent Agent, do hereby declare the nature of
this invention to be as follows:-
By aa dibenzimidazol is understood according to the papers of Hautzsch,
Ann. 249. 4 and Bamberger Ber. 24. 2083 the anhydroxanilide
N
N
CH,
C C
CH
NH
NH
described by Hübner Ann. 209. 370.
རལ་མ
This invention relates to the manufacture of diamido-derivatives of this and the
homologous compounds
N
NH, CH,
C-C
CH.NH,
NH
NH
Like the analogous diamines they possess the valuable quality of producing
substantive azo coloring matters for cotton dyeing.
The new diamines are formed by reducing the easily produced tetranitro-
substitution-products of the oxalylcompounds of the amines by means of the usual
5 reducing agents, for example, tin and hydrochloric acid.
For the first member of the series, tetranitroxanilide, which is already known, it
is advantageous to use a largely diluted acid, as the employment of concentrated
acid causes partial dissociation. The homologues, for instance, the tetranitrooxal-
o-toluid react also with more energetic reducing action, smooth in the sense of
closing the ring.

page_text: The easily soluble hydrochlorate salt, which is separated, is dissolved in water and,
by treatment with sodium sulphate, a sulphate salt is obtained which is with great
difficulty soluble in pure water, but is easily soluble in acidulated water.
Very good results are also obtained if the quantity of hydrochloric acid necessary
for the reduction is largely diluted with alcohol; from this solution the sulphate
salt is precipitated directly by means of sulphuric acid in the form of a yellow
powder.
The base, the m-m-diamido-a-a-dibenzimidazol, separates from the solutions of its
salts on addition of alkali, after some time, when in pure condition in form of
crystalline flakes of yellowish color. It dissolves sparingly in hot water, with
difficulty in alcohol somewhat more easily in hot amylalcohol, it is insoluble in
ether, benzene and chloroform. From the hot aqueous solution it separates on
cooling in form of a yellowish crystalline powder of microscopic needles united to
globular granules; brilliant needles are obtained by recrystallisation from amyl-
alcohol; the melting point is much above 300°.
The solutions of the base have green fluorescence which is especially beautiful
from the amylalcoholic solutions and also for the yellow colored solutions of
its salts.
The reduction of the tetranitrooxal-o-toluid proceeds more smoothly and also
much more easily. This product is formed quantitatively by the action of hot
fuming nitric acid, or of nitric acid and sulphuric acid upon oxal-o-toluid; it is
insoluble in most of the usual solvents, but very sparingly soluble in hot glacial-
acetic acid; its melting point is above 300°.
8
45
دو
tin
">
"
hydrochloric acid (25 per cent.)
are heated for some time on the waterbath.
From the solution, when freed from the tin, the base is precipitated by means of
sodium carbonate.
The m-m-diamido a-a-dimethyl a-a-dibenzimidazol separates from the solutions
of its salts on the addition of alkalies in the form of a gelatinous precipitate, which
on being heated forms crystalline flakes. It is soluble with great difficulty in
water, also in alcohol and amylalcohol, insoluble in most of the other usual solvents,
and has its melting point also above 300°. The sulphate, somewhat more easily
soluble in water, forms clusters of fine needles of golden brilliancy when dry.
By means of nitrous acid it is converted into the corresponding tetrazo compound,
and this compound furnishes azo coloring matters by combining with suitable
substances.
Dated this 18th day of August 1893.
ABEL & IMRAY,
Agents for the Applicant.

page_text: this invention and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement :-
By a a dibenzimidazol is understood according to the papers of Hautzsch,
Ann. 249. 4. and Bamberger Ber. 24. 2083 the anhydroxanilide
are diluted in twice or thrice the quantity of water and boiled continuously. After
all the tetranitrooxanilide has gone into solution the intensely yellow coloured
liquid is freed from the tin in a known manner for example, by means of sulphuretted
hydrogen, and the filtrate is vaporised in order to eliminate the excess of acid.
The easily soluble hydrochlorate salt, which is separated, is dissolved in water
and, by treatment with sodium sulphate, a sulphate salt is obtained which is with
great difficulty soluble in pure water, but is easily soluble in acidulated water.
Very good results are also obtained if the quantity of hydrochloric acid necessary
for the reduction is largely diluted with alcohol; from this solution the sulphate
is precipitated directly by means of sulphuric acid in the form of a yellow powder.
The base, the m-m-diamido-a-a dibenzimidazol, separates from the solutions of
its salts on addition of alkali, after some time, when in pure condition in form of
crystalline flakes of yellowish colour. It dissolves sparingly in hot water, with
difficulty in alcohol, somewhat more easily in hot amylalcohol, it is insoluble in
ether, benzol and chloroform. From the hot aqueous solution it separates on
cobling in form of a yellowish crystalline powder of microscopic needles united to
globular granules; brilliant needles are obtained by recrystallisation from
amylalcohol; the melting point is much above 300°.
--
The solutions of the base have green fluorescence which is especially beautiful
from the amylalcoholic solutions and also from the yellow coloured solutions of
its salts.

page_text: The reduction of the tetranitrooxal-o toluid proceeds more smoothly and also
much more easily.
This product is formed quantitatively by the action of hot fuming nitric acid or
of nitric acid and sulphuric acid upon oxal-o toluid; it is insoluble in most of the
usual solvents, but very sparingly soluble in hot glacial acetic acid; its melting
point is above 300°.
nydrochloric acid (40 per cent.)
are heated for some time on the water bath.
From the solution when freed from the tin, the base is precipitated by means of
sodium carbonate.
The m. m. diamido a a dimethyl a a dibenzimidazole separates from the solutions
of its salts on the addition of alkalies in the form of a gelatinous precipitate,
which on being heated forms crystalline flakes. It is soluble with great difficulty
in water, also in alcohol and amyalcohol, insoluble in most of the other usual
solvents and has its melting point also above 300°. The sulphate, somewhat more
easily soluble in water, forms clusters of fine needles of golden brilliancy when dry.
By means of nitrous acid it is converted into the corresponding tetrazo compound
and this compound furnishes azo colouring matters by combining with suitable
substances.
For example 13.2 parts by weight of m-m-diamido a-a-dibenzimidazol are
diazotised in the usual way with 27 parts by weight of sodium nitrite, then run
into a solution of 25 parts by weight of sodium naphthionate and 33 parts by
weight of soda and stirred for 12 hours.
The formation of the colouring matter begins at once, and is finished in 12 hours.
The colouring matter is isolated and purified in the usual way.
Instead of naphthionic acid other components may be used, for instance resorcin,
salicylic acid, a-naphtholsulphonic acid Nevile Winther, B-naphtholdisulphonic
acid R, amidonaphtholdisulphonic acid G, amidonaphtholdisulphonic acid H and
similar substances.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. The herein described manufacture of m. m. diamido a a dibenzimidazole and
its homologues by reducing tetranitrooxanilide and its homologues.
2. The conversion of the diamido compounds referred to in the first claim into
tetrazo compounds by the action of nitrous acid.
3. The employment of the tetrazo compounds referred to in the second claim for
the production of azo colouring matters.
4. The azo colouring matters obtained from the tetrazo compounds referred to
in the second and third claims.
Dated this 15th day of May 1894.
ABEL & IMRAY,
Agents for the Applicant.