Manufacture of a ẞ Naphthylamine Sulphonic Acid.
Year: 1894

page_text: Date of Application, 7th Aug., 1894
Complete Specification Left. 7th May, 1895-Accepted, 8th June, 1895
[Communicated from abroad by The Farbwerke, vormals MEISTER LUCIUS
& BRUNING, of Hoechst a Main, in the Empire of Germany, Chemical
Manufacturers.]
Manufacture of a ẞ Naphthylamine Sulphonic Acid.
I, OLIVER IMBAY, 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:-
The salts of ẞ naphthylsulphamic acid have been obtained by heating salts
of naphthylamine ortho sulphonic acid to temperatures of from 200° to 230° C.
The salts of a naphthylaminesulphamic acid behave in a totally different manner
as they are converted into the salts of a naphthylamine ortho sulphonic acid at a
temperature considerably lower.
a naphthylsulphamic acid or thionaphthamic acid was first obtained by Piria, as
well as naphthionic acid, by heating a nitro naphthaline for a considerable time
with aqueous alcoholic ammonium sulphite. It is obtained more advantageously by
means of the general method of W. Traube [Berl. Ber. Vol. 23 (1890) p. 1653 and
Vol. 24 (1891) p. 360] for the preparation of sulphamic acids of the aromatic
series, that is, by the action, moderated by cooling, of chlorsulphonic acid, sulphuric
anhydride or strong fuming sulphuric acid upon an excess of a-naphthylamine
diluted with a solvent.
The a-naphthylsulphamic acid contained in the product of the reaction in the
form of the naphthylamine salt is brought into solution as the ammonium salt.
according to Traube's method by means of aqueous ammonia, while the naphthylamine
solution may be used again after drying it and replacing the naphthylamine which
had been converted into a naphthylsulphamic acid.
To obtain a-naphthylamine-ortho-sulphonic acid the sodium salt of a-naphthyl-
sulphamic acid is best employed.
The latter is made by treating the solution of the ammonium salt, obtained as
above mentioned, with caustic soda or sodium carbonate. The sodium salt, which
is sparingly soluble in the cold, crystallises out on concentrating the solution, or it
can be precipitated from the solution with salt in laminæ free from water of
crystallisation.
It can be dried at 100° C. with decomposition.
To convert it into the a₁ ẞ, naphthylamine sulphonate of sodium, the well dried
sodium salt of a naphthylsulphamic acid is heated in a closed vessel in a thoroughly
dry atmosphere free from oxygen, for example, in a stream of carbonic acid gas,
for some hours to a temperature of from 185° to 190° C., that is until the dilute
solution of a sample, on boiling with hydrochloric acid and supersaturating with
caustic soda, no longer contains naphthylamine.
In carrying out the process described one is by no means bound to work within
the narrow limits of temperature 185° to 190° C. mentioned in the above example.
The transformation of the salts of a-naphthylsulphamic acid into salts of
a-naphthylamine ortho sulphonic acid takes place, although more slowly, at a
temperature 15° lower.
As, moreover, the transformation does not take place suddenly at the first
mentioned temperature but gradually, and as the resulting salt of a naphthylamine

page_text: ortho sulphonic acid can stand a temperature of 240° C. with decomposing, a higher
temperature may be chosen for the reaction.
The process is then completed in a correspondingly shorter time.
Dated this 7th day of August 1894.
ABEL & IMRAY,
Agents for the Applicant.
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 and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement :-
The salts of 3 naphthylsulphamic acid have been obtained by heating salts
of naphthylamine ortho sulphonic acid to temperatures of from 200° to 230° C.
The salts of a naphthylamine sulphamic acid behave in a totally different manner
as they are converted into the salts of a naphthylamine ortho sulphonic acid at a
temperature considerably lower.
a
naphthyl-sulphamic acid or thionaphthamic acid was first obtained by Piria, as
well as naphthionic acid, by heating a nitro naphthaline for a considerable time
with aqueous alcoholic ammonium sulphite. It is obtained more advantageously hy
means of the general method of W. Traube [Berl. Ber. Vol. 23 (1890) p. 1653, and
Vol. 24 (1891) p. 360] for the preparation of sulphamic acids of the aromatic
series, that is, by the action, moderated by cooling, of chlorsulphonic acid, sulphuric
anhydride or strong fuming sulphuric acid upon an excess of a-naphthylamine
diluted with a solvent.
The a
naphthylsulphamic acid contained in the product of the reaction in the
form of the naphthylamine salt is brought into solution as the ammonium salt
according to Traube's method by means of aqueous ammonia, while the naphthyl-
amine solution may be used again after drying it and replacing the naphthylamine
which had been converted into a naphthylsulphamic acid.
To obtain
a-naphthylamine-ortho-sulphonic acid the sodium salt of a-naphthyl-
sulphamic acid is best employed.
The latter is made by treating the solution of the ammonium salt, obtained as
above mentioned, with caustic soda or sodium carbonate. The sodium salt, which
is sparingly soluble in the cold, crystallises out on concentrating the solution, or it
can be precipitated from the solution with salt in laminæ free from water of
crystallisation.
It can be dried at 100° C. with decomposition.
To convert it into the a₁ ẞ, naphthylamine sulphonate of sodium, the well dried
sodium salt of a-naphthylsulphamic acid is heated in a closed vessel in a thoroughly
dry atmosphere free from oxygen, for example, in a stream of carbonic acid gas,
for some hours to a temperature of from 185° to 190° C., that is until the dilute
solution of a sample, on boiling with hydrochloric acid and supersaturating with
caustic soda, no longer contains naphthylamine.
In carrying out the process described one is by no means bound to work within
the narrow limits of temperature 185° to 190° C. mentioned in the above example.
The transformation of the salts of a-naphthylsulphamic acid into salts of
a-naphthylamine ortho sulphonic acid takes place, although more slowly, at a
temperature 15° lower.
As, moreover, the transformation does not take place suddenly at the first
mentioned temperature but gradually, and as the resulting salt of a naphthylamine

page_text: ortho sulphonic acid can stand a temperature of 240° C. without decomposing,
a higher temperature may be chosen for the reaction.
The process is then completed in a correspondingly shorter time.
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 :-
The herein described manufacture of a, ẞ, naphthylamine sulphonic acid by
heating salts of a-naphthylsulphamic acid to temperatures of 170° to 240° C.
Dated this 7th day of May 1895.
ABEL & IMRAY,
Agents for the Applicant.