Manufacture of Chlorinated Naphthalenesulphonic Acids.
Year: 1898

page_text: Manufacture of Chlorinated Naphthalenesulphonic Acids.
I, DR. CHRISTIAN RUDOLPH, of No. 16, Goethe Strasse, Offenbach a/Main, Germany,
Chemist, do hereby declare the nature of this invention to be as follows:-
-
This invention relates to the manufacture of chlorinated naphthalene-sulphonic
acids by the action of chlorine on naphthalene-sulphonic acids.
For this purpose solutions of naphthalene-sulphonic acids or their salts are treated
with chlorine which may be used in the gaseous state or may be caused to attack the
naphthalene-sulphonic acids or their salts at the time of its evolution from hypo-
chlorites and hydrochloric acid, chlorates and hydrochloric acid, manganese dioxide
and hydrochloric acid, or the like.
The chloronaphthalene-sulphonic acids thus obtained are valuable raw materials
for the manufacture of organic colouring matters.
The following examples serve to illustrate the process.
I. Manufacture of chloro-ẞ-naphthalene-sulphonic acids.
A. By chlorination with gaseous chlorine.
Chlorine gas is passed into a solution of 25 kilos. of sodium ẞ-naphthalene-sulphonic
acid in 300 kilos. of water until the whole has increased in weight to the amount of
7 kilos. the solution being externally cooled by water during the operation. The
chloro-ẞ-naphthalene-sulphonate is either salted out or separated by evaporation after
neutralisation with soda.
To purify the product and to separate the isomeric chloro-ẞ-naphthalene-sulphonic
acids which are formed the salts may be fractionally crystallised from water. Sodium
a-chloronaphthalene-S-sulphonate separates first and is followed by sodium a¹-chloro-
naphthalene-6-sulphonate. The isomeric acids can also be separated by taking
advantage of the difference between the solubility of their calcium salts, calcium
a-chloronaphthalene-6-sulphonate, unlike the a¹-3 salt, is sparingly soluble even in
boiling water.
B. By chlorinating with a hypochlorite and hydrochloric acid.
36 kilos, of sodium 8-naphthalene-sulphonate are dissolved in 400 kilos. of water
and the solution is mixed with 15 kilos. of a solution containing 7.5 per cent. of
sodium hypochlorite. 66 kilos. of hydrochloric acid of specific gravity 1.085 are then
added little by little and the whole is set aside for some time. When the chlorination
is finished the product is worked up in the manner described under A.
II. Manufacture of a'-chloro-82-83-naphthalene-disulphonic acid.
24 kilos. of manganese dioxide and 200 litres of hydrochloric acid of specific
gravity 1-19 are added to a solution of 85 kilos. of calcium 82-83 -naphthalene-
disulphonate in 300 kilos. of water. The mixture, which is at first black, becomes
decolorised in the course of time and when the chlorination is complete fornis a
yellowish white magma in which manganese dioxide can no longer be detected.
After dilution with water the mixture is made feebly alkaline with milk of lime and
filtered while boiling hot; the filtrate is evaporated to crystallisation and the calcium
chloro-naphthalenedisulphonate is pressed and converted into the sodium salt. The
chloronaphthalene-disulphonic acid produced is the a'-chloronaphthalene-82-83-disul-

page_text: phonic acid; its sodium salt and calcium salt are easily soluble in water and crystallise
in colourless, very slender needles.
The common naphthalene sulphonic acids may be chlorinated in the same or a
similar manner.
Dated this 7th day of September 1898
:
ABEL & IMRAY,
Agents for the Applicant,
Manufacture of Chlorinated Naphthalenesulphonic Acids.
I, DR. CHRISTIAN RUDOLPH, of No. 16, Goethe Strasse, Offenbach a/Main, Germany,
Chemist, 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:-
This invention relates to the manufacture of chlorinated naphthalenesulphonic
acids by the action of chlorine on naphthalenesulphonic acids.
For this purpose solutions of naphthalene-sulphonic acids or their salts are treated
with chlorine which may be used in the gaseous state or may be caused to attack the
naphthalene-sulphonic acids or their salts at the time of its evolution from hypo-
chlorites and hydrochloric acid, chlorates and hydrochloric acid, manganese dioxide
and hydrochloric acid, or the like.
The chloronaphthalene-sulphonic acids thus obtained are valuable raw materials
for the manufacture of organic colouring matters.
The following examples serve to illustrate the process.
I. Manufacture of chloro-ß-naphthalene-sulphonic acids.
A. By chlorination with gaseous chlorine.
Chlorine gas is passed into a solution of 25 kilos. of sodium ẞ-naphthalene-sul-
phonic acid in 300 kilos. of water until the whole has increased in weight to the
amount of 7 kilos., the vessel containing the solution being externally cooled by water
during the operation. The chloro-ß-naphthalene-sulphonate is either salted out or
separated by evaporation after neutralisation with soda.
To purify the product and to separate the isomeric chloro-ẞ-naphthalene-sulphonic
acids which are formed, the salts may be fractionally crystallised from water.
Sodium a-chloronaphthalene-83-sulphonate separates first and is followed by sodium-
a-chloronaphthalene-8-sulphonate.
The isomeric acids can also be separated by taking advantage of the difference
between the solubility of their calcium salts, calciuin a-chloronaphthalene-B³-sul-
phonate, unlike the a¹-84 salt, is sparingly soluble even in boiling water.
B. By chlorinating with a hypochlorite and hydrochloric acid.
36 kilos. of sodium 8-naphthalene-sulphonate are dissolved in 400 kilos. of water
and the solution is mixed with 15 kilos. of a solution containing 7.5 per cent, of
sodium hypochlorite. 66 kilos. of hydrochloric acid of specific gravity 1085 are
then added little by little and the whole is set aside for some time. When the
chlorination is finished the product is worked up in the manner described
under A.
II. Manufacture of a chloro-ẞ2 ẞ3-naphthalene-disulphonic acid.
24 kilos. of manganese dioxide and 200 litres of hydrochloric acid of specific
gravity 1.19 are added to a solution of 85 kilos. of calcium 82 83-naphthalene-di-
sulphonate in 300 kilos. of water. The mixture, which is at first black, becomes
decolorised in the course of time and when the chlorination is complete forms a
yellowish white magma in which manganese dioxide can no longer be detected.

page_text: After dilution with water the mixture is made feebly alkaline with milk of lime
and filtered while boiling hot; the filtrate is evaporated to crystallisation and the
calcium chloro-naphthalenedisulphonate is pressed and converted into the sodium
salt. The chloronaphthalenedisulphonic acid produced is the a¹-chloro-naphthalene-
82-83-disulphonic acid; its sodium salt and calcium salt are easily soluble in water
and crystallise in colourless, very slender needles.
The common naphthalenesulphonic acids may be chlorinated in the same or a
similar manner.
Having now particularly described and ascertained the nature of
invention and in what manner the same is to be performed, I declare that what
this
I claim is:
1. The herein described manufacture of chlorinated naphthalenesulphonic acids by
treating naphthalene-mono- and poly-sulphonic acids or their salts with chlorine gas
or with chlorine at the time of its evolution from mixtures such as hypochlorites,
chlorates or manganese dioxide with hydrochloric acid.
2. The chloronaphthalenesulphonic acids manufactured as above set forth.
ABEL & IMRAY,
Agents for the Applicant.
ABEL & IMRAY,
Agents for the Applicant.