The Manufacture or Production of Dye-stuffs.
Year: 1895

page_text: Date of Application, 27th Mar., 1895
Complete Specification Left, 27th Dec., 1895-Accepted, 1st Feb., 1896
BAYER & Co., of Elberfeld, Germany.]
The Manufacture or Production of Dye-stuffs.
I HENRY EDWARD NEWTON of The Office for Patents 6 Breams Buildings
Chancery Lane in the County of London Patent Agent, do hereby declare the
nature of this invention to be as follows:-
In the Specification of the German Patent No. 19224, dated 18th February
1882, it was stated that nitrosodimethylaniline hydrochloride and nitrosodiethyl-
aniline hydrochloride, when allowed to act on primary aromatic amines, yield tarry
products, owing to a further decomposition taking place. As described in the
Specification of the German Patent No. 58345, dated 8th October 1889, this
decomposition can be avoided, if the said process is effected in the presence of
muriatic acid. In this case, safranine-like dye-stuffs are produced.
My foreign correspondents have now found that the paranitroso derivatives of
monoalkylorthotoluidines show a behaviour materially differing from that of the
above-named nitroso derivatives. According to the researches of my foreign
correspondents, the paranitroso derivatives of monoalkylorthotoluidines, even on
the conditions prescribed in the Specification of the aforesaid German Patent
No. 19224, that is to say, in glacial acetic acid solution, and without the presence
of muriatic acid, act with readiness on primary aromatic amines, dye-stuffs being
thus formed.
The coloring matters thus obtained belong to the safranine series, and are
superior to the products hitherto known by their capacity for yielding very clear
and brilliant shades.
The researches of my foreign correspondents have shown that they are identical
with those safranine coloring matters produced by my foreign correspondents in
another way, viz., by subjecting to a joint oxidation one molecular proportion of
paramidomonoalkylorthotoluidine, together with two molecular proportions of any
primary aromatic base, and that their valuable properties are caused by the fact
that they contain the radicle of monoalkylorthotoluidine.
In order to illustrate this process of producing the dye-stuffs hereinbefore
defined, the following example is given, which, however, is merely typical. The
Darts are by weight.
COLORING MATTER OBTAINED FROM ONE MOLECULAR PROPORTION OF NITROSO-
MONOMETHYLORTHOTOLUIDINE AND TWO MOLECULAR PROPORTIONS, OF
ORTHOTOLUIDINE.
18-6 parts of nitrosomonomethyl orthotoluidine hydrochloride and 22 parts of
orthotoluidine, are dissolved in about 100 parts of alcohol or glacial acetic acid.
The resulting solution is beated by means of a water bath. A violent action
begins at once, and after the end of this violent action, the liquid is still heated
during about one hour. In case alcohol is used, the alcohol is then distilled off,
and the residue, after being acidulated by means the of muriatic acid, is treated

page_text: with hot water, in which the dye-stuff is soluble. The finished coloring matter is
separated by adding common salt to the resulting filtrate, and is then isolated by
filtering off, pressing, and drying.
The process proceeds in a manner analogous to that described in the above
example, if, on the one hand, the nitrosomonomethylorthotoluidine used therein is
replaced by the equivalent quantities of other nitrosomonoalkylorthotoluidines, or
if, on the other hand, corresponding quantities of aniline or other primary aromatic
amines, not substituted in the "para" position relatively to the amido group, are
substituted for the orthotoluidine used in the preceding example, that is to say, if
two molecular proportions of such other amines are allowed to act on one molecular
proportion of nitroso monoalkylorthotoluidine. According to the researches of my
foreign correspondents, mixtures of two primary aromatic amines can also be
used. If this case, it is not necessary that both amines be not substituted in
the "para" position relatively to the amido group. Thus, for instance, the
process readily proceeds on using a mixture of equal molecular proportions of
paratoluidine and orthotoluidine.
In the Specification of the above named German Patent No. 19224, it is further
stated, that the paranitroso derivatives of aromatic amines act on secondary and
tertiary aromatic amines, dye-stuffs being thus obtained which yield from red to
violet and blue shades, whereas the interaction of primary aromatic amines and
nitroso derivatives yields tarry products according to the same Specification as
herein before mentioned.
Up to the present time, it is not known in what manner the nitroso compounds
act on mixtures of primary and secondary, or of primary and tertiary aromatic
monoamines.
My foreign correspondents have now found that, contrary to the Specification of
the last named German Patent, the paranitroso compounds act with readiness in
the primary aromatic amines, even under the conditions given in the last mentioned
Specification, if the primary aromatic amines are used together with secondary and
tertiary aromatic amines. On using, for instance, one molecular proportion of
nitrosomonomethylorthotoluidine, one molecular proportion of paratoluidine and
one molecular proportion of monomethylorthotoluidine, the same safranine dye is
obtained (in a very pure state) which has also been produced by my foreign corre-
spondents in another way, viz., by subjecting to a joint oxidation paramidomono-
methylorthotoluidine, together with monomethylorthotoluidine and paratoluidine.
The last-defined new process for producing safranine dye-stuffs by acting with
nitroso derivatives on a mixture of primary and secondary aromatic monoamines,
or of primary and tertiary aromatic monoamines, can be generally applied, and it
is only necessary that the secondary and tertiary monoamines to be used be not
substituted in the "para" position relatively to the amido group.
This process is illustrated by the following example, which is however merely
typical, the parts being by weight.
DYE STUFF PRODUCED FROM ONE MOLECULAR PROPORTION OF NITROSO-
MONOMETHYLORTHOTOLUIDINE, ONE MOLECULAR PROPORTION OF PARA-
TOLUIDINE, AND ONE MOLECULAR PROPORTION OF MONOMETHYLORTHO-
TOLUIDINE.
11 parts of paratoluidine and 12 parts of monomethylorthotoluidine are dissolved
in 100 parts of alcohol and 18-6 parts of nitrosomonomethylorthotoluidine hydro-
chloride are added to the resulting solution, while being heated by means of a
water-bath. After adding the nitroso compound, a violent action soon begins, and
as soon as this violent action is finished, the intensely red-colored liquid mixture is
heated during one hour by means of a water bath. The alcohol is then distilled
off, and the residue, after being acidulated by means of muriatic acid, is treated

page_text: with hot water. After adding common salt to the solution obtained by filtration,
the safranine dye thus formed separates. It is purified by recrystallization.
Other dye-stuffs are obtained in a manner analogous to that described in the
preceding second example, if, on the one hand, equivalent quantities of other
nitroso compounds are substituted for the nitrosomonomethylorthotoluidine used,
or if, on the other hand, corresponding quantities of other primary, secondary, and
tertiary amido compounds are used in place of paratoluidine and monomethyl-
orthotoluidine, and if these amido compounds are allowed to act on nitroso
compounds.
In the production of the dye-stuffs herein before defined, my foreign corre-
spondents do not limit themselves to the particulars given in the preceding
examples, as all methods known and in use for preparing analogous dye-stuffs can
be used. Such modifications do not alter the nature of the present invention,
which, in general, relates to the production of safranine-like dye-stuffs, by acting
with nitrosomono alkylorthotoluidines on primary aromatic amines not substituted
in the "para" position relatively to the amido group, or on mixtures of equal
molecular proportions of two primary aromatic amines, the one of which, at least,
is not substituted in the "para" position relatively to the amido group, or by
acting with paranitroso compounds of aromatic monoamido products on mixtures
of a primary aromatic monoamine, and either a secondary or tertiary aromatic
monoamine not substituted in the "para" position relatively to the amido group.
Dated this 27th day of March 1895.
NEWTON & SON,
Agents for the Applicant.
1, 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 :-
In the Specification of the German Patent No. 19224, dated 18th February 1882,
it was stated, that nitrosodimethylanilinehydrochloride, and nitrosodiethylaniline
hydrochloride, when allowed to act on primary aromatic amines, yield tarry
products, owing to a further decomposition taking place. As described in the
Specification of the German Patent No. 58345, dated 8th October 1889, this
decomposition can be avoided if the said process is effected in the presence of
muriatic acid, safranine-like dye-stuffs being thus produced.
My foreign correspondents have now found, that the paranitroso derivatives of
monalkylortho-toluidines shew a behaviour materially differing from that of the
above named nitroso-derivatives. According to the researches of my foreign
correspondents, the paranitroso derivatives of monalkylorthotoluidines, even on the
conditions prescribed in the Specification of the aforesaid German Patent No. 19224,
that is to say, in glacial acetic acid solution, and without the presence of. muriatic
acid, act with readiness on primary aromatic amines, dye-stuffs being thus formed
which belong to the safranine series, and are superior to the products hitherto
known, by their capacity for yielding very clear & brilliant shades.
The researches of my foreign correspondents have shewn, that they are identical
with those safranine colouring matters produced by my foreign correspondents in
another way; riz., by subjecting to a joint oxidation one molecular proportion of
paramidomonalkylorthotoluidine, together with two molecula: proportions of any
primary aromatic base, and that their valuable properties are caused by the fact
that they contain the radicle of monoalkylorthotoluidine.

page_text: COLOURING MATTER OBTAINED FROM
ONE
MOLECULAR PROPORTION OF
NITROSO MONOMETHYLORTHOTOLUIDINE-HYDROCHLORIDE AND TWO
MOLECULAR PROPORTIONS OF ORTHO-TOLUIDINE.
18-6 parts of nitrosomonomethylorthotoluidine hydrochloride and 22 parts of
orthotoluidine, are dissolved in about 100 parts of alcohol. The resulting solution
is heated by means of a water-bath. If the action, which begins at once, is finished,
the liquid is acidulated by means of acetic acid, and the oxidation is completed
by gradually adding a 5 per cent. solution in water of 20 parts of potassium
dichromate. The alcohol is distilled off, and the residue, after being acidulated by
means of muriatic acid, is treated with hot water, in which the dye-stuff is soluble.
The finished safranine colouring matter is precipitated by adding common salt to
the resulting filtrate. It is then isolated by filtration, pressing, and drying, and
may be purified by redissolving if desirable.
The safranine dye-stuff thus produced is identical with that formerly produced
by my foreign correspondents by subjecting one molecular proportion of paramido-
monomethylorthotoluidine, together with two molecular proportions of ortho-
toluidine, to a joint oxidation."
The process proceeds in a manner analogous to that described in the above
example, if, on the one hand, the nitroso-monomethylortho-toluidine used therein
is replaced by the equivalent quantities of other nitrosomonoalkylortho-toluidines,
or if, on the other hand, corresponding quantities of aniline or other primary
aromatic amines, not substituted in the "para" position relatively to the amido
group, are substituted for the orthotoluidine used in the preceding example, that
is to say, if two molecular proportions of such other amines are allowed to act on
one molecular proportion of nitrosomonoalkyl orthotoluidine. According to the
researches of my foreign correspondents, mixtures of two primary aromatic
amines can also be used. In this case, it is not necessary that both amines be not
substituted in the "
"
para position relatively to the amido group. Thus, for
instance, the process readily proceeds on using a mixture of equal molecular
proportions of paratoluidine and orthotoluidine.
In the Specification of the above-named German Patent No. 19224, it is further
stated, that the paranitroso derivatives of aromatic amines act on secondary and
tertiary aromatic amines, dye stuffs being thus obtained which yield from red to
violet and blue shades, whereas the interaction of primary aromatic amines and
nitroso derivatives is said to yield tarry products.
Up to the present time it is not known in what manner the nitroso compounds.
act on mixtures of primary and secondary, or of primary and tertiary aromatic
amines.
My foreign correspondents have now found that, contrary to the Specification:
of the last named German Patent, the parauitroso compounds act with readiness
on the primary aromatic amines, even under the conditions given in the last
mentioned Specifications, if the primary aromatic amines are used together with
secondary and tertiary aromatic amines. On using, for instance, one molecular
proportion of nitrosomonomethylorthotoluidine, one molecular proportion of para-
toluidine, and one molecular proportion of monomethylorthotoluidine, the same
safranine dye is obtained (in a very pure state) which has also been produced by
my foreign correspondents in another way, viz., by subjecting to a joint oxidation;
paramido monomethylorthotoluidine together. with monomethylorthotoluidine and
paratoluidine.
The last: defined new process for producing safranine dyestuffs, by acting with
nitroso derivatives on a mixture of primary and secondary aromatic moṇamines,

page_text: or of primary and tertiary aromatic monamines, can be generally applied, and it
is only necessary that the secondary and tertiary monamines to be used be not
substituted in the "para" position relatively to the amido group.
This process is illustrated by the following example, which, however, is merely-
typical, the parts being by weight.
DYESTUFF
PRODUCED FROM ONE MOLECULAR PROPORTION OF NITROSO--
MONOMETHYLORTHOTOLUIDINE, ONE MOLECULAR PROPORTION OF PARA-
TOLUIDINE, AND ONE MOLECULAR PROPORTION OF MONOMETHYLORTHO
TOLUIDINE.
11 parts of paratoluidine and 12 parts of monomethyl ortho toluidine, are
dissolved in 100 parts of alcohol, and 186 parts of nitrosomonomethylortho-
toluidine hydrochloride are added to the resulting solution while being heated by
means of a water bath. After adding the nitroso compound, the action soon.
begins, and the so formed intensely red coloured liquid mixture is heated during one
hour by means of a water bath, and the resulting liquid is subsequently treated in.
the manner described in the preceding example A.
The safranine dye thus produced is identical with that formerly obtained by my
foreign correspondents froin equal molecular proportions of paramidomonomethyl-
orthotoluidine, mono methylorthotoluidine, and paratoluidine.
Other dyestuffs are obtained in a manuer analogous to that described in the
Example B, if, on the one hand, equivalent quantities of other nitroso compounds.
are substituted for the nitrosomono-methyl-orthotoluidine, or if, on the other
hand, corresponding quantities of other primary and secondary or tertiary
amido compounds are used in place of paratoluidine, and monomethylortho-
toluidine.
Thus, for instance, the colouring matter obtainable in an analogous manner
from equal molecular proportions of aniline, mouethylorthotoluidine, and nitroso-
mcnomethylaniline hydrochloride, has been found to be identical with that safranine
dye which my foreign correspondents have formerly produced from equal molecular
proportions of paramidomonomethylaniline, monethylorthotoluidine, and aniline,
by joint oxidation.
In the production of the dyestuffs hereinbefore defined, my foreign corre-
spondents do not limit themselves to the particulars given in the preceding examples,.
as all methods known and in use for preparing analogous dye-stuffs can be used.
Such modifications do not alter the nature of the present invention, which, in
general, relates to the production of safranine-like dyestuffs, by acting with
nitrosomonoalkylorthotoluidines on primary aromatic amines, not substituted in
the "para" position relatively to the amido group, or on mixtures of equal
molecular proportions of two primary aromatic amines, the one of which at least is
not substituted in the "para" position relatively to the amido group, or by acting
with paranitroso compounds of aromatic monamido products on mixtures of a
primary aromatic monamine, and either a secondary or tertiary aromatic mon-
amine, not substituted in the "para position relatively to the alkyl amido
group.
"
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 production of safranine dyes from nitroso compounds of monalkylortho-
toluidines, by acting with one molecular proportion thereof, in the presence of
suitable solvents or diluents, either
(a) on two molecular proportions of primary aromatic monamido compounds,.
L
il to the amid

page_text: (b) on a mixture containing one molecular proportion of any primary aromatic
monamido whatever, & one molecular proportion of a primary aromatic
amido compound not substituted in the "para" position relatively to the
amido group.
2. The process for producing safranine colouring matters from nitroso
derivatives of aromatic monoamido compounds, which process consists in allowing
one molecular proportion thereof to act, in the presence of suitable solvents or
diluents, on mixtures containing one molecular proportion of any primary aromatic
mouamido compound whatever, & one molecular proportion of a secondary or
tertiary aromatic monamido compound, not substituted in the "para" position
relatively to the alkylamido group.
Dated this 27th day of December 1895.
NEWTON & SON,
Agents for the Applicant.