Improvements in the Production of Para magenta and its Homologues from the Corresponding Leucobases.
Year: 1892

page_text: Date of Application, 27th Dec., 1892
Complete Specification Left, 27th Sept., 1893-Accepted, 28th Oct., 1893
PROVISIONAL SPECIFICATION.
[Communicated from abroad by THE FARBWERKE vormals MEISTER LUCIUS AND
BRUNING, of Hoechst a/Main, in the Empire of Germany, Manufacturers.]
Improvements in the Production of Para magenta and its Homologues
from the Corresponding Leucobases.
I, OLIVER IMRAY of No. 28 Southampton Buildings, in the County of London,
Chartered Patent Agent, do hereby declare the nature of this invention to be as
follows:-
As is known, leucobases of the diamido-triphenyl-methan and triamido-triphenyl-
methan series, the amido groups of which are alkylised, can, by oxidising, be
converted without difficulty into the corresponding carbinoles (coloring matter
bases); for example, the tetramethyl-diamido-triphenyl-methan can be converted
into malachite green, the hexa-methyl-diamido-triphenyl-methan into hexa-methyl-
pararosaniline, and so on.
But hitherto it has not been possible to convert in a satisfactory manner the
triamido-triphenyl-methan (paraleukaniline) and its three homologues:
the triamido-diphenyl-tolylmethan
the triamido-ditolyl-phenylmethan
the triamido-tritolylmethan,
by oxidising, into the corresponding carbinoles (rosaniline bases); (see
E. & O. Fischer, Liebig's Annalen 194. 273).
It was in fact by reason of the difficulties encountered in the oxidation of these
leucobases that Fischer's beautiful methods for producing magenta failed in being
taken up by manufacturers.
As the leucobases by well known methods can be produced easily in nearly
theoretical yield and at a low price, attempts to solve the question of oxidation
have not been wanting. Thus it has been tried, to oxidise the acetyl-compounds
of the leucobases, it being expected that thereby the oxidation could be restricted
on the methan hydrogen alone (Renouf Ber. d. d. Ch. Ges. XVI 1303). It is
said, that in this operation the oxidising proceeds smoothly, but unfortunately the
method is too complicated and too expensive. It has farther been proposed to
employ various oxidising agents of mild action: arsenic acid (Annalen 194. 273),
dry metallic hydroxides, as in the German Patent No. 19484 dated 3rd January 1882,
chromic acid, as in the refused application for a German Patent No. 4809 dated
24th December 1884, and finally chlorinated quinones for example chloranil in
alcoholic solution as in the Geruian Patent No. 11412 dated 11th November 1879.
None, however of all these methods came seriously into use, because either the
yield was very inferior or the materials used cost too much.
Now my foreign correspondents have remarked that the leucanilines most easily
dissolve in acetone and that this solution can be diluted to a very great extent
with, for example, a solution of common salt, without the leucaniline being pre-
cipitated; and, farther, that in no other manner than in such a solution is it
possible to smoothly convert by oxidising the leucanilines into rosanilines.
For the acetone may be substituted any other solvent of the leucanilines that
can be mixed with water, and to which can be added a salt for precipitating the
formed magenta, such a solvent is methyl-ethyl acetone. My correspondents have
thus succeeded in making available for manufacturing purposes the synthesis of
F

page_text: A4 DILE.
A vessel of about 100 litres capacity, furnished with a cover and an agitator, is
placed on a water bath: The cover is furnished with a cock and refrigerator for
distillation of the acetone, also with a feed opening. The water bath is filled
with cold water which at the same time acts as refrigerator. The vessel is charged
with:
10 kgs. of paraleucaniline (base, dry or in the form as it comes from the press,
of known standard)
15 kgs. of acetone.
After a few revolutions of the agitator the base becomes dissolved; the agitation
is continued while there are added
From 10 to 12 kgs. of diluted acetic acid
10 litres of common salt solution
2 kgs. of common salt.
For about half an hour the oxidising is then effected by means of hyperoxide of
manganese in form of finely powdered manganite or of Weldon-mud. The
agitation of the cold material is continued for another hour, after which the water
bath is heated to from 60° to 70° C. whereby the acetone is distilled off. There
remains in the vessel the para-magenta in admixture with basic manganese salts
and common salt solution containing acetic acid. The latter is drawn off to be 2
employed for farther operations, or the acetic acid may be recovered from it. The
coloring matter is caused to dissolve by repented boiling with water, is filtered,
and precipitated from the reunited filtrates by means of common salt. It is
obtained in pure state, filtered off and dried.
This process, if carried out with the necessary precautions, gives very nearly the 2
theoretical yield.
The same method is used for converting by oxidising the three homologues of
the paraleucaniline into the corresponding coloring matters.
Dated this 27th day of December 1892.
ABEL & IMRAY,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in the Production of Para magenta and its Homologues
from the Corresponding Leucobases.
I, OLIVER IMRAY, of No. 28 Southampton Buildings, in the County of London,
Chartered 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 :-
As is known, leuco bases of the diamidotriphenylmethan and triamidotriphenyl-
methan series, the amido groups of which are alkylised, can by oxidising, be
converted without difficulty into the corresponding carbinoles (coloring matter
bases); for example, the tetramethyl-diamido-triphenyl-methan can be converted
into malachite green, the hexa-methyl-diamido-triphenylmethan into hexa-methyl-
pararosaniline, and so on.
But hitherto it has not been possible to convert in a satisfactory manner the
triamido-triphenylmethan (para-leukaniline) and its three homologues
the triamido-diphenyl-tolylmethan.
the triamido-ditolyl-phenylmethan.
the triamide trital.

page_text: It was in fact by reason of the difficulties encountered in the oxidation of these
leuco bases that Fischer's beautiful methods for producing magenta failed in being
taken up by manufacturers.
As the leuco bases. by well known methods can be produced easily in nearly
theoretical yield and at a low price, attempts to solve the question of oxidation
have not been wanting. Thus it has been tried, to oxidise the acetyl compounds
of the leuco bases, it being expected that thereby the oxidation could be restricted
on the methan hydrogen alone (Renouf Ber. d. d. Ch. Ges. XVI 1303).
It is said, that in this operation the oxidising proceeds smoothly, but unfortunately
the method is too complicated and too expensive. It has farther been proposed to
employ various oxidising agents of mild action; arsenic acid (Annalen 194. 273)
dry metallic hydroxides, as in the German Patent 19484 dated 3rd January 1882,
chromic acid, as in the refused application for a German Patent No. 4809 dated
24th December 1884 and finally chlorinated quinones for example chloranil in
alcoholic solution as in the German Patent 11412 dated 11th November 1879.
None however of all these methods came seriously into use, because either the
yield was very inferior or the materials used cost too much.
Now my foreign correspondents have remarked that the leucanilines can be
smoothly converted by oxidising with manganese peroxide and acetic acid (or
tartaric acid and oxalic acid) into the corresponding rosanilines, when there are
present certain solvents in which the leucaniline base dissolves easily, whereas the
rosaniline salt dissolves with difficulty or is insoluble, and which besides can be
mixed with water and salt solutions.
Such solvents are in the first place acetone, further, methyl-ethyl-ketone or ethyl
or methyl alcohol. In acetone and in methyl-ethyl-ketone the leucaniline bases
dissolve extraordinarily easily at ordinary temperature already, and the solution
can be diluted to a large extent with water or common salt solutions without that
the base be separated. The rosaniline salts are entirely insoluble in acetone.
When acetone is employed the operation in consideration of this fact is carried
out at ordinary temperature and it will give very nearly the theoretical yield.
In alcohol (or methyl alcohol) the leuco bases dissolve sparingly at ordinary tem-
perature, but copiously at temperatures nearing the boiling point of the respective
alcohol and this even when the alcohols are largely diluted with common salt
solution. In such a mixture of alcohol and common salt solution the rosaniline
salts are practically insoluble. Therefore the operation is carried out at higher
temperatures when ethyl or methyl alcohol are employed as solvents.
My correspondents have thus succeeded in making available for manufacturing
purposes the synthesis of paramagenta as it was first applied by E. & O. Fischer.
EXAMPLE A.
Using acetone (or methyl-ethyl-ketone):
A vessel of about 100 litres capacity, furnished with a cover and an agitator, is
placed on a water bath. The cover is furnished with a cock and refrigerator for
distillation of
مملح
ALL

page_text: water-bath is heated to from 60° to 70° C: whereby the acetone is distilled off. There
remains in the vessel the para magenta in admixture with basic manganese salts
and common salt solution containing acetic acid. The latter is drawn off to be
.employed for farther operations, or the acetic acid may be recovered from it.
The colouring matter is caused to dissolve by repeated boiling with water, is filtered
and precipitated from the reunited filtrates by means of common salt. It is
obtained in pure state, filtered off and dried.
This process if carried out with the necessary precautions, gives very nearly
the theoretical yield.
in such a way buat the refrigerator
mentioned can, by a simple manipulation be converted into a reflux-refrigerator and
vice-versa.
The vessel is charged with:
10 kgs. of leucaniline-base
15
alcohol
"
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common salt
6
from 8 to 10 kgs. of diluted acetic acid;
the mixture is now heated under reflux-refrigeration to from 60 to 70° C. and for
an hour the oxidising effected by means of the suitable quantity of manganese
peroxide (manganite or Weldon mud) and while agitating rapidly. 'When the
oxidising is complete, the refrigerator is inverted and the larger part of the alcohol
distilled off. The further treatment is effected in exactly the same manner as
described in example A.
The same methods are used for converting the three homologues of the para-
leucaniline into the corresponding colouring matters.
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 :-
A manufacture of triamido triphenyl carbinol, triamido-diphenyltolylcarbinol,
triamido phenyl ditolylcarbinol or triamido tritolyl carbinol by dissolving the
corresponding leuco bases in acetone or methyl-ethyl-ketone or in ethyl- or methyl
alcohol and oxidising them in presence of water and common salt by means of
peroxide of manganese and acetic acid or tartaric acid or oxalic acid.
Dated this 23rd day of September 1893.
ABEL & IMKAY,
Agents for the Applicant.