Manufacture of Methyl-w-Sulphonic Acids of Primary Aromatic Amines and of Mixed Amido-azo-compounds resulting there- from.
Year: 1899

page_text: PROVISIONAL SPECIFICATION.
Manufacture of Methyl-w-Sulphonic Acids of Primary Aromatic
Amines and of Mixed Amido-azo-compounds resulting there-
from.
I, CHARLES DENTON ABEL, of Birkbeck Bank Chambers, Southampton Buildings,
in the County of London, Consulting Engineer and Chartered Patent Agent, do
hereby declare the nature of this invention (as communicated to me from abroad by
Actien-Gesellschaft für Anilin-Fabrikation, of Berlin, in the Empire of Germany,
Chemical Manufacturers) to be as follows:-
My foreign correspondents have found that by treating anhydroformaldehyde
compounds of aromatic amines having the typical formula R.N: CH, with sulphurous
acid or bisulphites there are formed acids of the following typical constitution:
R. NH. CH, SO, H in which R indicates an aromatic radicle. The acids thus obtained,
which will be hereinafter referred to as the methyl-w-sulphonic acids of the amido-
compounds, are well characterised products distinguished by their great tendency to
crystallise. The are easily soluble in sodium carbonate solution and in alkali iyes.
The manufacture of these methyl-w-sulphonic acids is effected by energetically
mixing the anhydroformaldehyde compounds of the aromatic primary amines with
aqueous bisulphite solution in the presence of or absence of a suitable solvent, such
as ether, benzene, toluene or the like.
My correspondents have also found that mixed amido-azo-compounds can easily be
obtained from the above described methyl-w-sulphonic acid by coupling it with
suitable diazo-compounds and then eliminating the group CH. SO, H by treating the
azo-compounds with alkalies, alkali carbonates, alkaline earths, or mineral acids.
The substitution of an atom of hydrogen for the group CH. SO, H commences already
at ordinary temperature and can be completed by slightly heating; in most cases it
is not necessary to operate in closed vessels at increased pressure.
The new process above described is of great technical value as it allows the pro-
duction with very good yield of mixed amido-azo-compounds, that is to say amido-
azo-compounds the nuclei of which contain the radicles of two different amido groups.
Hitherto the production of such mixed amido-azo-products, even when possible was
attended by great difficulties.
As is well known, the usual method for the production of amido-azo-compounds
consists in first preparing diazo-amido-compounds and then converting them inte
amido-azo-products by treatment with amines. Even if mixed diazo-amido-com-
pounds are supplied in this process there generally result from it amido-azo-compounds
containing the same nuclei, only small quantities of the mixed amido-azo-product:
being formed.
By the new method described mixed amido-azo-compounds are directly produce..
with quantitative yield, the substitution of the amido-group by the group CH2. SO₂H
excluding the intermediate formation of diazo-amido-products but not in any way
preventing the combination with diazo-compounds for the production of the azo-
derivatives.

page_text: The invention may be illustrated by the following examples:
A. Production of methyl-w-sulphonic acids of primary aromatic amines.
(1.) 11.9 kilos. of anhydroformaldehyde-ortho-toluidine and 60 kilos. of bisulphite
solution of 32° Bé. specific gravity are vigorously inixed together by means of a rapid
agitator. The temperature of the mixture rises slightly and the oil dissolves after a
short time, whereupon the new compound begins to crystallise in the shape of large
leaves. Soon afterwards the whole mass solidifies forming a thick paste consisting of
white crystals of methyl-ortho-toluidine-w-sulphonic acid.
2.) 155 kilos. of anhydroformaldehyde-3-naphthylamine are dissolved in 30 kilos.
of benzene and energetically mixed with 60 kilos. of a bisulphite solution of 32° Bé.
specific gravity. Very soon the reaction begins; it is accelerated and completed by
moderately heating and then after a short time the mass solidifies forming a paste
of slightly yellowish crystals. Methyl-3-naphthylamine-w-sulphonic acid thus obtained
is considerably less soluble than the corresponding derivative of ortho-toluidine. In-
stead of the anhydroformaldehyde compounds of o-toluidine and B-naphthylamine
those of other primary aromatic amines can be similarly converted into the corre-
sponding methyl-w-sulphonic acids.
B. Production of mixed amido-azo-compounds from the methyl-w-sulphonic acids
of primary aromatic amines.
1). The solution of paranitrodiazobenzene chloride prepared in the known manner
from 6.9 kilos. of para-nitraniline is added to a solution of 10.5 kilos. of the sodium salt
of monoinethyl-aniline-w-sulphonic acid and 13-6 kilos. of sodium acetate in 50 litres
of water while the mixture is cooled. The combination is complete after a few minutes.
The separated colouring matter is filtered, mixed to a paste with water and heated with
At once the smell of
a solution of 6 kilos. of sodium hydroxyde in 200 litres of water.
formaldehyde is observed and on acidifying a sample of the liquid, sulphurous acid
escapes. After boiling for half an hour the reaction is completed; the colouring matter
is filtered and washed with hot water. It forms a red brown powder which after
recrystallisation from benzene melts at 210°-212° C. (Nölting & Binder, Berichte der
deutschen chemischen Gesellschaft XX, 3015 give the melting point 203°-205°).
The hydrochloride of the dyestuff crystallises in the shape of steel blue leaflets
resembling those of amido-azo-benzene.
2). By substituting in the preceding example for the sodium salt of methyl-
aniline-w-sulphonic acid the equivalent quantity of the sodium salt of methyl-ortho-
toluidine-w-sulphonic acid and by using quick lime instead of sodium hydroxyde for
the elimination of the group CH..SO, H the following product is obtained.
The new compound crystallises from its solution in alcohol in the shape of small
red-brown crystals melting at 200°-201°. Its hydrochloride resembles that of the
product described in the preceding example.
3.) 10.5 kilos. of the sodium salt of mono-methylaniline-w-sulphonic acid and
13.6 kilos. of sodium acetate are dissolved in 50 litres of water and to this is added a
solution of diazo-benzene-meta-sulphonic acid prepared from 10 kilos. of the sodium
salt of metanilic acid. After the combination is complete, which will be found to be
the case after about half an hour, the clear solution of the colouring matter formed
is heated with 17 kilos. of hydrochloric acid. Sulphurous acid is at once eliminated,
and, on refrigeration of the liquid, amido-azobenzene-meta-sulphonic acid separates
in the shape of an orange-brown crystalline powder.
4). The solution of B-diazonaphthalene chloride prepared from 74 kilos. of
B-naphthylamine is added to the solution of 115 kilos. of methyl-ortho-toluidine-w-
sulphonate of sodium and 13.6 kilos. of sodium acetate in 50 litres of water. The

page_text: combination is completed by stirring the liquid for some time. The separated colour-
ing matter is filtered, mixed with the solution of 6 kilos. of sodium hydroxyde and
heated. Even while the product is cold the smell of formaldehyde is observed; after
heating the colouring matter completely dissolves and as soon as the sulphonic-methyl
group is split off the new dyestuff which is formed again separates from the solution.
It crystallises from benzene in the form of lustrous brown-red crystals melting at
about 175° C.
ABEL & IMRAY,
Agents for the Applicant.
Manufacture of Methyl-w-Sulphonic Acids of Primary Aromatic
Amines and of Mixed Amido-azo-compounds resulting there-
from.
I, CHARLES DENTON ABEL, of Birkbeck Bank Chambers, Southampton Buildings,
in the County of London, Consulting Engineer and Chartered Patent Agent, do
hereby declare the nature of this invention (as communicated to me from abroad
by Actien-Gesellschaft für Anilin-Fabrikation, of Berlin, in the Empire of Germany,
Chemical Manufacturers) and in what manner the same is to be performed, to he
particularly described and ascertained in and by the following statement:-
My foreign correspondents have found that by treating anhydroformaldehyde
compounds of aromatic amines having the typical formula R. N: CH, with sulphurous
acid or bisulphites there are formed acids of the following typical constitution:
R. NH. CH, SOH in which R indicates an aromatic radicle. The acids thus
obtained, which will be hereinafter referred to as the methyl-w-sulphonic acids of the
amido-compounds, are well characterised products distinguished by their great
tendency to crystallise.
They are easily soluble in sodium carbonate solution and in alkali lyes.
The manufacture of these methyl-w-sulphonic acids is effected by energetically
mixing the anhydroformaldehyde compounds of the aromatic primary amines with
aqueous bisulphite solution in the presence of or absence of a suitable solvent, such
as ether, benzene, toluene or the like.
My correspondents have also found that mixed amido-azo-compounds can easily be
obtained from the above described methyl-w-sulphonic acids by coupling them with
suitable diazo-compounds and then eliminating the group CH. SO, H by treating the
azo-compounds with alkalies, alkali carbonates, alkaline earths, or nineral acids.
The substitution of an atom of hydrogen for the group CH2. SO,H commences already
at ordinary temperature and can be completed by slightly heating; in most cases it
is not necessary to operate in closed vessels at increased pressure.
The new process above described is of great technical value as it allows the pro-
duction with very good yield of mixed amido-azo-compounds, that is to say, amido-
azo-compounds the nuclei of which contain the radicles of two different amido-groups.
Hitherto the production of such mixed amido-azo-products, even when possible was
attended by great difficulties.
As is well known, the usual method for the production of amido-azo-compounds
consists in first preparing diazo-amido-compounds and then converting them into
amido-azo products by treatment with amines. Even if inixed diazo-amido-com-
pounds are supplied in this process there generally result from it amido-azo-
compounds containing the same nuclei, only small quantities of the mixed amido-
azo-products being formed.

page_text: By the new method described mixed amido-azo-compounds are directly produced
with quantitative yield, the substitution of the amido-group by the group CH. SO,H
excluding the intermediate formation of diazo-amido-products but not in any way
preventing the combination with diazo-compounds for the production of the azo-
derivatives.
The invention may be illustrated by the following examples:
A. Production of methyl-w-sulphonic acids of primary aromatic amines.
(1) 119 kilos. of anhydroformaldehyde-ortho-toluidine and 60 kilos. of sodium
bisulphite solution of 32° Bé. specific gravity are vigorously mixed together by
means of a rapid agitator. The temperature of the mixture rises slightly and the oil
dissolves after a short time, whereupon the new compound begins to crystallise in
the form of large laminae, Soon afterwards the whole mass solidifies, forming a
thick paste consisting of white crystals of methyl-ortho-toluidine-w-sulphonic acid.
2.) 155 kilos. of anhydr oformaldehyde-3-naphthylamine are dissolved in 30 kilos.
of benzene and energetic ally mixed with 60 kilos. of a sodium bisulphite solution of
32° Bé. specific gravity. Very soon the reaction begins; it is accelerated and
completed by moderately heating and then after a short time the mass solidifies
forming a paste of slightly yellowish crystals. Methyl-ß-naphthylamine-w-sulphonic
acid thus obtained is considerably less soluble than the corresponding derivative of
ortho-toluidine.
Instead of the anhydroformaldehyde compounds of o-toluidine and ẞ-naphthylamine
those of other primary aromatic amines can be similarly converted into the corre-
sponding methyl-w-sulphonic acids.
B. Production of mixed amido-azo-compounds from the methyl-w-sulphonic acids
of primary aromatic amines.
1) The solution of paranitrodiazobenzene chloride prepared in the known manner
from 6.9 kilos. of para-nitraniline is added to a solution of 10.5 kilos. of the sodium
salt of monomethyl-aniline-w-sulphonic acid and 13.6 kilos. of sodium acetate in
50 litres of water while the mixture is cooled. The combination is complete after a
few minutes. The separated colouring matter is filtered, mixed to a paste with
water and heated with a solution of 6 kilos. of sodium hydroxide in 200 litres of
water. At once the smell of formaldehyde is observed and on acidifying a sample of
the liquid, sulphurous acid escapes. After boiling for half an hour the reaction is
completed; the colouring matter is filtered and washed with hot water. It forms a
red brown powder which after recrystallisation from benzene melts at 210° to 212° C.
(Nolting & Binder, Berichte der deutschen chemischen Gesellschaft XX, 3015 give
the melting point 203° to 205° C.). The hydrochloride of the dyestuff crystallises in
the form of steel blue leaflets resembling those of amido-azo-benzene.
2.) By substituting in the preceding example for the sodium salt of methyl-aniline-
w-sulphonic acid the equivalent quantity of the sodium salt of methyl-ortho-toluidine-
w-sulphonic acid and by using quick lime instead of sodium hydroxyde for the
limination of the group CH. SOH the following product is obtained.
The new compound crystallises from its solution in alcohol in the form of small
red-brown crystals melting at 200° to 201° C. Its hydrochloride resembles that of
the product described in the preceding example.
3.) 10.5 kilos. of the sodium salt of mono-methylaniline-w-sulphonic acid and
13.6 kilos. of sodium acetate are dissolved in 50 litres of water and to this is added a
solution of diazo-benzene-meta-sulphonic acid prepared from 10 kilos. of the sodium
salt of metanilic acid. After the combination is complete, which will be found to be
the case after about half an hour, the clear solution of the colouring matter formed is

page_text: heated with 17 kilos. of hydrochloric acid. Sulphurous acid is at once eliminated,
and, on refrigeration of the liquid, amido-azobenzene-meta-sulphonic acid separates
in the form of an orange-brown crystalline powder.
The
4) The solution of B-diazonaphthalene chloride prepared from 7.4 kilos. of
B-naphthylamine is added to the solution of 11.5 kilos. of methyl-ortho-toluidine-w-
sulphonate of sodium and 13.6 kilos. of sodium acetate in 50 litres of water.
combination is completed by stirring the liquid for some time. The separated
colouring matter is filtered mixed with the solution of 6 kilos. of sodium hydroxide
and heated. Even while the product is cold the smell of formaldehyde is observed;
after heating the colouring matter completely dissolves and as soon as the sulphonic-
methyl group is split off the new dyestuff which is formed separates from the
solution. It crystallises from benzene in the form of lustrous brown-red crystals
melting at about 175° C.
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 methyl-w-sulphonic acids of the typical
constitution R-NH-CH, SO₂H, in which R indicates an aromatic radicle, by treating
with sulphurous acid or alkali bi-sulphites the anhydroformaldehyde compounds of
primary aromatic amines.
2. The methyl-w-sulphonic acids manufactured as above set forth.
3. The herein described manufacture of mixed amidoazo-compounds by combining
diazo-compounds with the methyl-w-sulphonic acids referred to in Claim 1 and
treating the azo-compounds thus obtained with caustic alkalies, alkali carbonates,
alkaline earths or mineral acids.
4. The mixed amidoazo-compounds manufactured as set forth in Claim 3.