The Manufacture of New Leuco Compounds, and the Production of Colouring Matters therefrom.
Year: 1893

page_text: Date of Application, 10th July, 1893
Complete Specification Left, 9th Apr., 1894-Accepted, 12th May, 1894
PROVISIONAL SPECIFICATION.
[Communicated from abroad by THE FARBENFABRIKEN vormals FRIEDRICH
BAYER & Co., of Elberfeld, in the Empire of Germany.]
The Manufacture of New Leuco Compounds, and the Production of
Colouring Matters therefrom.
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:-
My foreign correspondents have described, in the Specification of Letters Patent
No. 11876, dated 25th June 1892, the production of coloring matters (capable of
withstanding the action of alkalies) from alkylated amido benzhydrols and oxazine
dye stuffs (such as the so-called new blue or the like), and conversion thereof (by
a further treatment with oxidising agents) into new dye-stuffs, which show similar
dyeing properties, and contain two chromophoric groups.
The leuco products which are derived from the aforesaid two groups of coloring
matters, have not been prepared hitherto..
My foreign correspondents have now found that these leuco compounds can be
obtained either on employing, in the processes described in the said Specification
No. 11876, in place of the alkylated diamidobenzhydrols, the corresponding
methane derivatives containing the group CH, instead of CHOH (for
instance, alkylated diamidodiphenylmethane, the analogues or homologues thereof),
and condensing the latter with oxazines, or on condensing alkylised diamidobenz-
hydrels with the leuco compounds derived from oxazines.
In the former process, whilst the condensation is taking place, the oxazine dye
stuff becomes probably reduced, this reduction being caused by the hydrogen atoms
which are freed on the combination of the alkylated amidodiphenylmethanes, or
the like, with the oxazines employed.
If, for instance, tetraalkyldiamidodiphenylmethane and new blue are used, the
condensation which takes place may be represented by the following equation
-
The following equation is given in order to illustrate the condensation process
taking place on the employment of alkylated diamidobenzhydrols, and leuco
derivatives of oxazines, for instance, tetraalkyldiamidobenzhydrol, and the leuco
product of new blue:-
(Alkyl), NCH₁\
(Alkyl), NC.H
HO\
+ CHÊNHON (Alkyl), HCl =

page_text: The researches of my foreign correspondents have shown that the last defined
leuco products are, on oxidation with lead dioxide, or similar oxidising agents, first
converted into dye stuffs which contain but one chromophoric group (as described
in the said Specification No. 118762), and are, by a further oxidation, transformed
into the coloring matters which contain two chromophoric groups, as likewise
defined in the aforesaid Specification.
In order to illustrate more in detail the new processes, the following examples
are given, the parts mentioned being by weight :-
FIRST EXAMPLE.
CONDENSATION OF NEW BLUE K-WITH TETRAMETHYLDIAMIDODIPHENYL-
METHANE.
31 parts of the so called new blue R and 26 parts of tetramethyldiamido-
diphenylenemethane are dissolved in 200 parts of alcohol. The resulting solution
is heated at 80 degrees centigrade during some hours. The original violet color of
the liquid gradually changes into a blue, and finally into slightly green color, which
does not alter on further heating. The solution contains the so formed leuco
compound, and the latter can be isolated in a suitable manner.
CONDENSATION OF TETRAMETHYLDIAMIDOBENZHYDROL AND THE LEUCO
DERIVATIVE OF NEW BLUE R.
31 parts of new blue R, dissolved in 250 parts of alcohol, are reduced by adding
the necessary quantity of zinc dust and hydrochloric acid. The end of the
reduction is distinguishable by the discoloration of the alcoholic liquid. After
filtering off the zinc dust in excess, 27 parts of tetramethyldiamidobenzhydrol are
added, and the resulting liquid is then heated at from 70 to 80 degrees centigrade
during 12 hours. The condensation is finished after this time, and the leuco
product can be isolated from the alcoholic solution.
OXIDATION OF THE, LEUCO BASE OBTAINABLE AS DESCRIBED IN THE ABOVE
FIRST OR SECOND EXAMPLE.
The solution of the leuco compound produced as described in the foregoing first
or second example (when cooled) is mixed with 25 parts of acetic acid, and then
with 125 parts of a lead dioxide paste (containing 20 per cent. of pure lead dioxide).
After some time, the lead dissolved is precipitated by means of dilute sulphuric
acid. The lead sulphate is filtered off, and the resulting filtrate is mixed with
25 parts of zinc chloride, and such a quantity of common salt as is necessary for
separating the dye stuff. The latter is filtered off, and purified by redissolving and
precipitation.
The researches of my foreign correspondents have shown that the so formed
coloring matter is identical with that described in the first example of the said
Specification No. 11876.
My foreign correspondents have ascertained that on employing, in place of
125 parts of the lead dioxide paste used in the above third example, 250 parts of
the same paste, a coloring matter is produced, which contains two chromophoric
groups, and is identical with the dye stuff resulting, as described in the second
example.of the, aforesaid Specification. No. 1187692.
The tetramethyldiamidodiphenylmethane employed in the above first example,
can be replaced by the corresponding quantities of its analogues or homologues.

page_text: In place of tetramethyldiamidobenzhydrol used in the above second example,
other alkylated amidobenzhydrols, such as tetraethyldiamidobenzhydrol, dimethyl-
diethyldiamidobenzhydrol, or the like, can be employed.
The new blue R used in the foregoing examples can be replaced by the
corresponding quantities of the analogous diethyl derivative, or the oxazine dye
stuffs employed in the processes described in the said Specification No. 11876**
(resulting from nitrosomono, or nitrosodialkylaniline, or nitromonoalkylortho-
toluidine, or the like, and betanaphthol or hydroxynaphthols), or other oxazine
dye stuffs.
Of course, in place of the leuco compound of new blue R, all leuco products
derived from oxazine coloring matters can be employed in the same manner.
The coloring matters obtainable in the manner hereinbefore defined, are partly
identical with those resulting as described in the said Specification No. 1187692.
My foreign correspondents have described, in the above three examples, distinct
methods of producing the new leuco compounds, and converting the latter into dye
stuff's containing either one, or two chromophoric groups. Naturally, they do not
limit themselves to the directions given in these three examples, as the processes
hereinbefore defined can be varied, and, with regard to the production of the dye
stuffs, all those modifications can be used which are mentioned in the said
Specification No. 11876 %. The nature of this invention is not altered by such
modifications, or the like, as it relates generally to the production of leuco
compounds, either from alkylated diamidodiphenylmethane or the analogues or
homologues thereof, and oxazines, or from alkylated diamidobenzhydrols, or the
analogues or homologues thereof, and leuco derivatives of oxazines, and to the
conversion of the resulting leuco products into dye stuffs.
1004
NEWTON & SON,
Agents for the Applicant.
The Manufacture of New Leuco Compounds, and the Production of
Colouring Matters therefrom.
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 :-
My foreign correspondents have described in the Specification of Letters Patent
No. 11876, dated 25th June 1892, the production of coloring matters (capable of
withstanding the action of alkalies) from alkylated amidobenzhydrols. and oxazine
dye-stuffs (such as the so-called new blue or the like), and the conversion thereof
(by a further treatment with oxidising agents) into new dye-stuffs having similar
dyeing properties, containing two chromophoric groups.
The leuco derivatives of the aforesaid two groups of colouring matters have not
hitherto been prepared. My foreign correspondents have. however, found that
such leuco derivatives can be obtained either using in the processes described in
the said Specification No. 11876%, in place of the alkylated diamidobenzhydrols,
the corresponding methane derivatives containing the group CH₂→ instead
of CHOH (for instance, alkylated diamidodiphenylmethane or homologues
thereof), and condensing the latter with oxazine dye-stuffs, or by condensing
alkylated diamidobenzhydrols with the leuco derivatives of oxazine dye-stuffs.
→>
In the former process, the oxazine dye-stuff probably becomes reduced while the
condensation is taking place, the reduction being caused by the hydrogen freed by
the combination of the alkylated diamidodiphenylmethanes, or the like, with the
oxazine dye-stuffs.

page_text: If, for instance, tetraalkyldiamidodiphhenylmethane and new blue are used, the
condensation which takes place may be represented by the following equation, that
is to say, molecular proportions of the two compounds are combined :-
NC IL
CH, CH,NON (Alkyl), CI =
Cl
(Alkel NCH
The following equation is given to illustrate the condensation taking place on
using alkylated diamidobenzhydrols and leuco derivatives of oxazines, for instance,
tetraalkyldiamidobenzhydrol and the leuco derivative of new blue, in which process
also molecular proportions of the two compounds are condensed :-
(Alkyl), NCH₂
(Alkyl), NCH
H
+ CH,NHON (Alkyl), HCl =
OH
CONDENSATION OF NEW BLUE R WITH TETRAMETHYLDIAMIDODIPHENYL-
METHANE.
31 parts of the so-called new blue R (Meldola blue) and 26 parts of tetramethyl-
diamidodiphenylmethane, are dissolved in 250 parts of alcohol, and the solution is
maintained at 80 degrees centigrade during several hours. The original violet
color of the liquid gradually changes into a blue, and finally into a greenish
color, which does not alter on further heating. The solution then contains the
leuco compound, which can be isolated in a suitable manner, for instance, by
adding water to the alcoholic solution, and filtering off the precipitate.
CONDENSATION OF TETRAMETHYLDIAMIDOBENZHYDROL AND THE LEUCO
DERIVATIVE OF NEW BLUE R.
31 parts of new blue R (Meldola blue), dissolved in 250 parts of alcohol, are
reduced by adding the necessary quantity of zinc dust and muriatic acid, the
completion of the reduction being distinguishable by the decoloration of the
alcoholic liquid. After filtering off the unused, zinc dust, 27. parts of tetra

page_text: methyldiamido benzhydrol are added, and the liquid is then heated at from 70 to.
80 degrees centigrade during 12 hours, when the condensation is finished. The
leuco derivative can be isolated from the alcoholic solution, for example, by adding-
water and filtering off the precipitate.
OXIDATION OF THE LEUCO BASE OBTAINABLE AS DESCRIBED IN THE ABOVE
FIRST OR SECOND EXAMPLE.
When cool, the solution of the leuco derivative produced as described in the-
foregoing first or second example, is mixed with 50 parts of acetic acid and
125 parts of a lead dioxide paste (containing 20 per cent. of pure lead dioxide,.
and affording a quantity of oxygen corresponding to one atom per molecule of the
leuco compounds used) are then added. After some time, the dissolved lead is.
precipitated by means of dilute sulphuric acid. The lead sulphate is filtered, off,
and the filtrate is mixed with 25 parts of zinc chloride, and such a quantity of
common salt as is necessary to separate the dye stuff. The latter is filtered off
and purified by redissolving it and reprecipitating.
The researches of my foreign correspondents have shown that the coloring
matter so formed is identical with that described in the first example of the said
Specification No. 11876 of 1892.
My foreign correspondents have ascertained that on using, in place of 125 parts
of the 20 per cent. lead dioxide paste prescribed in the above. third example,.
250 parts of the same paste, that is to say, a quantity of lead dioxide which will
afford a quantity of oxygen corresponding to 2 atoms per molecule of the said
leuco compounds, a coloring matter is produced which contains two chromophoric
groups identical with the dye-stuff prepared in the manner described in the second.
example of the aforesaid Specification No. 11876 of 1892.
Instead of the tetramethyldiamidodiphenylmethane prescribed in the above.
first example, the corresponding quantities of its homologues can be used.
In place of tetramethyldiamidobenzhydrol prescribed in the above second
example, other alkylated diamidobenzhydrols, such as tetraethyldiamidobenzhydrol,.
dimethyldiethyldiamidobenzhydrol, or the like, can be used.
Instead of the new blue R prescribed in the foregoing examples, corresponding
quantities of the analogous dye-stuff from nitrosodiethylanilinehydrochloride and
betanaphthul, or of the oxazine dye-stuffs mentioned in the said Specification
No. 11876 (formed from nitrosomonoalkylaniline or nitrosodialkylaniline, or
nitrosomonoalkylorthotoluidine or the like, and beta- naphthol, or hydroxy beta
naphthols) can be used.
As a matter of course, instead of the leuco derivative of new blue R, all leuco.
derivatives of the last defined oxazine coloring matters can be used in the same.
manner.
The coloring matters obtainable in the manner hereinbefore defined, are
identical with the respective dye-stuffs resulting as described in the Specification.
of the said Letters Patent No. 118769.
My foreign correspondents have described in the above three examples, distinct
methods of producing the new leuco compounds, and of converting these latter-
into dye-stuff's containing either one or two chromophoric groups. Naturally,
they do not limit themselves to the directions given in these three examples,.
as the methods illustrated herein can be varied. The oxidation of the leuco
compounds can also be effected by means of other suitable oxidising agents, for
instance, ammonium persulphate, or atmospheric oxygen, or the like.
In case
atmospheric oxygen is used, a current of air is allowed to pass through the-
solutions of the leuco compounds until the oxidation is completed. The nature of
this invention is not altered by such modifications or the like, as it relates.

page_text: generally to the production of leuco compounds either from alkylated diamido-
diphenylmethane, or the analogues or homologues thereof, and oxazines, or from
alkylated diamido benzhydrols, or the analogues or homologues thereof, and leuco
derivatives of oxazines, and to the conversion of the leuco products into
dye-stuffs.
Having now particularly described and
and in what manner the same is to be
abroad, I declare that what I claim is :-
ascertained the nature of this invention
performed, as communicated to me from
1. The production of leuco compounds by condensing molecular proportions of
alkylated diamidodiphenyl methanes, or homologues thereof, and the oxazine
dye-stuffs obtainable by the action of nitroso derivatives of dialkylaniline, mono-
alkylaniline, or mono-alkyl-ortho-toluidine, or betanaphthol, or hydroxy-beta-
naphthols.
2. The production of leuco compounds by condensing molecular proportions of
alkylated diamidobenzhydrols and the leuco products of the oxazine dye-stuffs
obtained by the action of nitroso derivatives of dialkylaniline, monoalkylaniline, or
monoalkylorthotoluidine, on betanaphthol or hydroxybetanaphthols.
3. The conversion of the leuco compounds produced by the processes herein-
before defined, or by any other process producing the like result, into dye-stuffs,
which process consists in oxidising the said leuco compounds.
4. As new products of manufacture, the new leuco compounds produced by
the processes herein before defined, or by any other process producing the like
result.
NEWTON & SON,
Agents for the Applicant.