turing Process for Separating the so called G-Naphthylamine d-Sulphonic Acid from the so called -Naphthylamine ẞ-Sulphonic Acid.
Year: 1888

page_text: Date of Application, 16th Jan., 1888
Complete Specification Left, 24th Sept., 1888
Complete Specification Accepted, 26th Oct., 1888
[Communicated from abroad by THE ACTIENGESELLSCHAFT FÜR ANILIN FABRIKATION,
Berlin, in the German Empire, Manufacturing Chemists.}
o Derin, the Cerman Empire, Manufacturing
Process for Separating the so called G-Naphthylamine d-Sulphonic
Acid from the so called ẞ-Naphthylamine ẞ-Sulphonic Acid.
1, CHARLES DENTON ABEL of No. 28 Southampton Buildings, Chancery Lane, in
the County of Middlesex, Consulting Engineer and Patent Agent do hereby declare
the nature of this invention to be as follows:-
This invention relates to a process for separating the so called -naphthylamine
6-sulphonic acid from the so called ẞ-naphthylamine B-sulphonic acid, which is based
upon the discovered fact, that the copper salts as well as the lead salts of the
B-naphthylamine 8-sulphonic acid and of the B-naphthylamine ẞ-sulphonic acid show
a great difference as regards their solubility in water.
The B-naphthylamine ẞ-sulphonate of copper is obtained in lustrous crystals which
are scarcely soluble in cold water, and in hot water are only slightly soluble, whereas
the B-naphthylamine 8-sulphonate of copper dissolves freely in cold water.
A similar difference exists between the lead salts; the 3-sulphonate is precipitated
more readily than the 8-sulphonate, so that the two salts can be separated by
filtration.
The following example will show the manner of proceeding. 20 parts of the
sodium salt of the mixture of the two acids are dissolved in 300 parts of boiling water
and this solution is mixed with 10 parts of sulphate of copper dissolved in 20 parts
of water. When cooled the precipitated -naphthylamine B-sulphonate of copper is
separated by filtration. The free B-naphthylamine 8-sulphonic acid is obtained by
adding sulphuric or hydrochloric acid to the remaining solution; or the B-naphthy-
lamine 8-sulphonate of copper can by addition of soda, be converted into the sodium
salt.

page_text: In order to obtain the pure B-naphthylamine-8-sulphonic acid, it is advisable to
convert the acid separated from the copper salt into the barium salt and to purify the
latter by crystallising.
The same result may be arrived at by an even simpler method. It is only necessary
to convert the ẞ-naphthylamine-6-sulphonic acid and not the whole quantity of the
B-naphthylamine sulphonic acids into the copper salt; for this purpose the addition
of the solution of sulphate of copper must only be continued as long as a precipitate
B-naphthylamine-6-sulphonate of copper is formed.
of
The sulphate of copper in the above process can of course be replaced by other
copper salts soluble in water, and some other well crystallising salt of the d-acid can
be taken in place of the above mentioned barium salt.
If the lead salts are employed, the process is quite analogous.
ABEL & IMRAY,
Agents for the Applicant.
Acid from the so called ẞ-Naphthylamine-ß-Sulphonic Acid.
I, CHARLES DENTON ABEL of No. 28 Southampton Buildings Chancery Lane in
the County of Middlesex Consulting Engineer and Patent Agent do hereby declare 2
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 thereof :-
This invention relates to a process for separating the so called B-naphthylamine-
8-sulphonic acid from the so called ẞ-naphthylamine-ß-sulphonic acid, which is based
upon the discovered fact, that the copper salts-as well as the lead salts of the
B-naphthylamine-d-sulphonic acid and of the B-naphthylamine-ß-sulphonic acid shew
a great difference as regards their solubility in water.
The B-naphthylamine-6-sulphonate of copper is obtained in lustrous crystals, which
are scarcely soluble in cold water, and in hot water are only slightly soluble, whereas the
B-naphthylamine-8-sulphonate of copper dissolves freely in cold water.
A similar difference exists between the lead salts; the B-sulphonate is precipitated
more readily than the 8-sulphonate, so that the two salts can be separated by
filtration.
The following example will shew the manner of proceeding. 20 parts of the
sodium salt of the mixture of the two acids are dissolved in 300 parts of boiling

page_text: water and this solution is mixed with 10 parts of sulphate of copper dissolved in
20 parts of water, when cooled, the precipitated ẞ-naphthlyamine-B-sulphonate of
copper is separated by filtration. The free B-naphthylamine-6-sulphonic acid is
obtained by adding sulphuric or hydrochloric acid to the remaining solution; or-the
B-naphthylamine 8-sulphonate of copper can, by addition of soda, be converted into
the sodium salt.
In order to obtain the pure ẞ-naphthylamine-8-sulphonic acid, it is advisable to
convert the acid separated from the copper salt into the barium salt, and to purify the
latter by crystallising.
The same result may be arrived at by an even simpler method. It is only necessary
to convert the B-naphthylamine-6-sulphonic acid, and not the whole quantity of
B-naphthylamine-sulphonic acids, into the copper salt; for this purpose the addition
of the solution of sulphate of copper must only be continued as long as a precipitate
B-naphthylamine-6-sulphonate of copper is formed.
of
The sulphate of copper, in the above process, can of course be replaced by other
copper salts soluble in water, and some other well crystallising salt of the d-acid can
be taken in place of the above mentioned barium salt.
If the lead salts are employed, the process is quite analogous.
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 process for separating the so called B-naphthylamine-d-sulphonic
acid from the so called "B-naphthylamine-6-sulphonic acid by forming their copper or
lead salts in hot aqueous solution, and cooling the solution so as to precipitate the less
soluble salt.
Dated this 20th day of Santamben 1888
ABEL & IMRAY,
Agents for the Applicant.