Process for the Partial Separation of Schäffer's Monosulpho-acid from the Alphamonosulpho-acid of Betanaphtol.
Year: 1884

page_text: Process for the Partial Separation of Schäffer's Monosulpho-acid
from the Alphamonosulpho-acid of Betanaphtol.
PROVISIONAL SPECIFICATION,
I, HERBERT JOHN HADDAN, of the firm of Herbert and Company, Patent
Agents, of 67, Strand, in the City of Westminster, Civil Engineer, do hereby declare
the nature of said Invention for "PROCESS FOR THE PARTIAL SEPARATION OF
SCHAFFER'S MONOSULPHO-ACID FROM THE ALPHAMONOSULPHO-ACID OF BETA-
NAPHTOL," a communication to me from abroad by The Farbenfabriken vorm,
Fr Bayer & Co of Elberfeld, Germany, to be as follows:-
The partial separation of Schäffer's monosulpho-acid from the mixture of this
acid with the so-called alpha-monosulpho-acid of betanaphtol, obtained by rapid
sulphonizing at a moderate temperature, is based on the different solubility of the
two isomeric naphtol-monosulpho-acids in water and may be effected as follows:
a, by neutralizing the mixture with caustic or carbonated alkaline carths,
subsequently boiling and evaporating, or
b, by neutralizing with sodic or potassio carbonate or other carbonates of
alkalies, in the cold state, or
c. by neutralizing with caustic alkali up to about two thirds of the acid and
allowing the mixture to cool.
First method: as soon as the mixture of betanaphtol and sulphuric acid, pro-
duced by the rapid sulphonizing at a moderato temperature, has been poured into
cold water and stirred, it is neutralized with caustic alkaline earths, for instance
lime or baryta, or the carbonates of the same, subsequently boiled, and filtered
while hot. The product of filtration is then boiled down as long as the salt of
Schäffer's sulpho-acid is precipitated.
This precipitato is then separated, by filtration, from the salt of the alpha-
monosulpho-acid of betanaphtol still remaining in solution. In this manner up to
four fifths of the total quantity of the monosulpho-acid of Schäffer may be
separated.
Second method: The aqueous solution of the naphtol sulpho-acid mixed with
sulphuric acid is neutralized with carbonates of alkalies, such as sodic or potassic
Dine A1

page_text: carbonate, in a cold state, whereby from 4/5 to 5/6 of the Schäffer sulpho-acid is
precipitated as alkaline salt, which may be mechanically separated from the
sulpho-acid remaining in solution,
Third method: The aqueous solution of the naphtol sulpho-acid serving as
starting point in the first method is mixed with about two thirds of the quantity 5
of caustic alkali which would be necessary for neutralizing the whole. In cooling,
about 4/5 of the Schäffer sulpho-acid is precipitated as acid alkali-salt. The
product of filtration contains the new alpha-acid with a small quantity of Schäffer's
monosulpho-acid and some unimportant impurities.
The product of filtration obtained by any of the three methods described is 1
immediately applicable for the manufacture of azo-dyes.

page_text: COMPLETE SPECIFICATION.
OF BETA-
I, HERBERT JOHN HADDAN, of the firm of Herbert and Company, Patent Agents,
of 67, Strand in the City of Westminster, Civil Engineer, do hereby declaro
the nature of said invention for "PROCESS FOR THE PARTIAL SEPARATION OF
SCHAFFER'S MONOSULPHO-ACID FROM THE ALPHAMONOSULPHO-ACID
NAPITOL," a communication to me from abroad by The Farbenfabriken vorm,
Fr. Bayer and Co, Elberfeld, Germany, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement :-
It is known, through the specification of Gorman Patent N° 18027, that, in
carrying out the process of rapid sulphonating at a low temperature, described
in the said specification, a mixture is produced which contains, besides Schäffer's
monosulpho-acid of the botanaphtol, another acid called the alpha monosulpho-acid
of the beta-naphtol.
As the alpha monosulpho-acid produced in this manner gives finer colours than
Schäffer's acid and is therefore more valuable than the latter, it is desirable to
eliminate from the mixture as far as possible Schäffer's mono-sulpho-acid which
may be considered as an impurity.
The process proposed and described for this purpose in the said German patent
specification N° 18027 consists in separating the soda-salts by means of spirits.
The present invention relates to other methods of separation, which removo
Schäffer's acid, not perfectly, it is true, but which are much simpler and cheaper.
The process is based upon the different degrees of solubility possessed by the
salts of the two isomeric naphtol-monosulpho-acids in water, and it can be carried
out in several ways.
I. As soon as the composition (namely the mixture of betanaphtol and sulphuric
acid produced by rapid sulphonizing at a moderato temperature) is poured into
cold water (one part, in weight, of the composition to 10 parts of water) and
stirred, it is neutralized by carthy alkalies or the carbonates of the same (such as
lime, baryta etc), then boiled and filtered while hot.
The filtrate is then condensed by evaporation, as long as the salt of Schäffer's
sulpho-acid continues to form a deposit, which is then separated by filtration from
the still impure salt of the now alpha monosulpho-acid of the betanaphol still
remaining in the solution.
In this way as much as 4/5 of the Schäffer monosulpho-acid can be separated.
II. The mixture containing naphtolsulpho-acid, mentioned under 1, is diluted
with water (1 part of the mixturo to about 2 parts of water) and neutralized at a
low temperature with carbonates of alkalies, such as soda or potash, both being
preferably used in a solid state, Aftor neutralizing, from 4/5 to 5/6 of Schäffer's
Bulpho-acid have been separated as an alkali salt, in the shape of a whito
crystalline precipitate which is then mechanically separated from the new sulpho-
salt remaining in tho solution.

page_text: III. A watery solution of the naphtolsulpho-acid mixture named in I, preferably
about 1 part (in weight) of the mixture to three parts of water, is mixed with
about 2/3 of the quantity of caustic alkali which would be requisite to neutralize
the whole.
By allowing the solution to cool, about 4/5 of the Schäffer sulpho-acid is
separated as an acid alkali salt.
The filtrate contains the new alpha-acid, a little of Schäffer's monosulpho-acid,
and some trifling impurities.
The filtrates, nearly freed from the Schäffer monosulpho-acid in the manner
described in I, II, and III, are suitable for the immediate production of azo-dyes.
Before submitting these colours to the market, they may be relieved of the
trifling quantity of colouring matter produced by the Schäffer mono-sulpho-acid
which would slightly deteriorate the same.
It is possible, however, to relieve the filtrates of the last remnant of Schäffer's
mono-sulpho-acid, for instance by the method of separation with alcohol, described
in the said German Potent No 18027, or by the method of separation by means of
diazo benzol described in the German Patent specification N° 26231, or by any
other suitable method.
Having now particularly described and ascertained the nature of the said
invention, and in what manner the same is to bo performed, I declare that what
I claim is
The partial separation of Schäffer's monosulpho-acid from the mixture of the
same with the so called alphamonosulpho-acid of the betanaphtol produced by rapid
sulphonizing at a moderate temperature.
a-By neutralizing the mixture with earthy alkalies or the carbonates of the
same, then boiling the product and concentrating it by evaporation.
Or b-By neutralizing with soda or potash, or other carbonates of alkalies, in a
cold state.
Or c-By neutralizing with about 2/3 of the quantity of limo necessary for
complete neutralization and allowing the mixture to cool.
And also by the mechanical separation of the salts of Schäffer's monosulpho acid
thus formed, from the slightly impure salt of alphamonosulpho acid remaining in
the solution.
T
100K