Processes for the Production of Certain Salts of Beta-sulpho-naph- thalene, and for the Separation of Alpha- and Beta-sulpho- naphthalenes.
Year: 1894

page_text: Date of Application, 2nd Mar., 1894
Complete Specification Left, 1st Dec., 1894-Accepted, 5th Jan., 1895
PROVISIONAL SPECIFICATION.
Processes for the Production of Certain Salts of Beta-sulpho-naph-
thalene, and for the Separation of Alpha- and Beta-sulpho-
naphthalenes.
We, SAMUEL BAGSTER BOULTON, THOMAS BURT HAYWOOD and HAROLD
EDWIN BOULTON, trading under the Firm of Burt Boulton & Haywood of
64 Cannon Street, in the City of London, and HUBERT FERGUSSON, of Prince
Regents Wharf, Silvertown, Chemist, do hereby declare the nature of this
invention to be as follows:-
This invention has for its object firstly, the production of certain salts of beta-
sulpho-naphthalene, direct from the impure acid solution obtained by sulphonating
naphthalene with sulphuric acid in the heat, and secondly to effect the separation
of the beta from the alpha-sulpho-naphthalene, this process being based on that
above mentioned.
For carrying out the first named process, we prepare crude beta-sulpho-
naphthalene from naphthalene and strong sulphuric acid after the manner well
known to manufacturers, and we then dilute the melt by pouring it into, say five
times its bulk of water..
After cooling and filtering to remove any unconverted naphthalene, we add to
the solution so obtained; a solution of a metallic salt, such as one of those mentioned
below; almost immediately after the addition, a crystalline precipitate is formed,
and goes on forming so. long as the metallic salt is added, and so long as there
remains any free beta-sulpho-naphthalene. We then separate the crystalline
precipitate from its mother liquor by filtration and further treatment in a centrifugal
machine, or by any other convenient and suitable process, and finally we obtain
the said salt in a pure state by recrystallization or other known means.
The other bodies such as alpha-sulpho-naphthalene contained in the original
melt, either do not form salts in this manner, or the salts remain in solution if
formed. Further, if only the theoretical quantity of metallic salt be used to give
a salt with the beta-sulpho-naphthalene present, then the whole of the beta-sulpho-
naphthalene will be converted in spite of the presence of other bodies usually
present in a properly prepared melt.
We find that salts of the following metals may be used, among others, in the
manner described above.
Copper; iron, manganese, nickel, cobalt, zinc, magnesium, calcium, cadmium.
As (with the exception of that of copper) the salts obtained from the above
metals are only slightly soluble in water, nearly the whole of the beta-sulpho-
naphthalene in the melt may be obtained direct in the form of one of these salts.
The iron salt is only soluble in water to the extent of about 0.5 part in 100 parts
and the magnesium salt to the extent of about 0-75 in 100.
The process for the separation of the alpha- and the beta-sulpho-naphthalene
is based upon the re-action as described above.
When naphthalene is sulphonated with strong sulphuric acid, both the alpha and
beta modifications of the mono-sulpho acid are formed, but in varying proportions,
according to the temperature at which the operation is worked.
Now if to the diluted melt there is added a solution of one of the metallic salts
above mentioned there will be obtained as a crystalline precipitate the salt of nearly

page_text: the whole of the beta-sulpho-naphthalene present. And if we employ a salt the
metal of which forms only a very slightly soluble salt with beta-sulpho-naphthalene
then we remove all but traces of beta-sulpho-naphthalene from the solution. Such
a metal is, for example, iron, whose salt with beta-sulpho-naphthalene is only
soluble in cold water at the rate of about 0.5 per cent.
Where practicable we prefer to use the sulphates of the metals, as the sulphuric acid
liberated by the re-action goes only to increase the amount of free sulphuric acid
already present, whereas if other salts such as the chlorides were used, the
acids liberated would prove more difficult to deal with.
Although any of the other metals above mentioned would serve the purpose, we
will by way of example proceed to describe the use of iron, in putting into practice
this process.
After making crude sulpho-naphthalene from naphthalene and sulphuric acid in
the manner well known to manufacturers, we dilute the melt, with say, five times its
bulk of water, or even less, and allow it to stand till cold; we then filter, to
separate any unconverted naphthalene.
To this solution we then add with constant stirring a concentrated solution of
iron sulpate, testing from time to time as the iron sulphate is being added, and we
stop the addition when no further precipitate takes place on adding a drop of
iron sulphate solution to a small portion of the mixture which has been filtered into
a test glass.
When this point is reached, we know that we have added sufficient iron sulphate
to produce the iron salt with all the beta-sulpho-naphthalene present. After
standing some time to allow all the iron salt which will separate to do so, we filter
the mixture by any convenient means and we free the precipitate from the mother
liquor by spinning in a centrifugal machine and washing with water; or by using
any other convenient process.
The solid portion, now being free from the impurities contained in the mother
liquor, and consisting of the iron salt of nearly pure beta-sulpho-naphthalene, we
dissolve or mix with boiling water, and add thereto carbonate of sodium until all
the iron is precipitated in the form of carbonate, and the sodium has taken the
place of the iron in combination with the beta-sulpho-naphthalene.
The precipitated carbonate of iron is filtered off and washed with water, and
the mother liquor and washings are put together and treated according to the
destination of the sodium salt of the beta-sulpho-naphthalene. The sodium salt
is the form which is required for the manufacture of beta-naphthol, the principal
body made from beta-sulpho-naphthalene.
The iron carbonate obtained as above may be used for making further iron salt
of beta-sulpho-naphthalene, either by adding direct to the diluted melt, warming
if necessary, or it may be dissolved in sulphuric acid and so converted again
into sulphate of iron.
The original mother liquor (from the treated melt) and the washings from
the precipitate may be used for diluting a fresh melt or may be directly
neutralised with milk of lime, and the alpha-sulpho-naphthalene recovered therefrom
in the form of the calcium salt in the manner usually employed, that is, by
filtering to separate the sulphate of lime formed, and evaporation and crystallisation
of the liquor to obtain the salt of alpha-sulpho-naphthalene. In the case where
much alpha-sulpho-naphthalene is present in the melt, we prefer to neutralise at
once after the separation of the beta salt, but where only small quantities are
present, we prefer to use the mother liquor for diluting a fresh melt.
Dated this 2nd day of March 1894.
.. .11

page_text: Processes for the Production of Certain Salts of Beta-sulpho-naph-
thalene, and for the Separation of Alpha- and Beta-sulpho-
naphthalenes.
We, SAMUEL BAGSTER BOULTON, THOMAS BURT HAYWOOD, and HAROLD
EDWIN BOULTON, trading under the Firm of Burt Boulton and Haywood, of
64 Cannon Street in the City of London, and HUBERT FERGUSSON, of Prince
Regent's Wharf, Silvertown, 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 has for its object firstly the production of certain salts of beta-
sulpho-naphthalene direct from the impure acid solution obtained by sulphonating
naphthalene with sulphuric acid in the heat, or from auy acid solution containing
beta-sulpho-naphthalene, and secondly to effect the separation of the beta
from the alpha-sulpho-naphthalene, this process being based upon that above
mentioned.
For carrying out the first named process we prepare, for example, crude beta-
sulpho-naphthalene from naphthalene and strong sulphuric acid after the manner
well-known to manufacturers and we then dilute the melt by pouring it into,
say, five times its bulk of water.
After cooling and filtering to remove any unconverted naphthalene we add to
the solution so obtained a solution of a metallic salt such as one of those obtained
from the list of metals given below; almost immediately (in most cases) after
the addition, a crystalline precipitate is formed and goes on forming so long as
the metallic salt is added and so long as there remains any free beta-sulpho-
naphthalene.
We then separate the crystalline precipitate from its mother liquor by filtration
and further treatment in a centrifugal machine or by any other convenient and
suitable process, and finally we obtain the said salt in the pure state by
recry stallisation or other known means.
.
Should however the metallic salt used be insoluble or only slightly soluble in
water, then it may be added to the solution of beta-sulpho-naphthalene in the state
of powder or ground up with water or in any other suitable manner, and in order
to facilitate the reaction the mixture may be boiled and when the reaction is
complete the mixture allowed to cool.
The other bodies contained in the original melt, such as alpha-sulpho-naphthalene,
either do not form salts in this manner or the salts remain in solution if formed.
Further if only the theoretical quantity of metallic salt be used to give a salt of
the metal with beta-sulpho-naphthalene then the whole of the beta-sulpho-naphthalene
will be converted in spite of other bodies usually present in a properly prepared
melt.
As examples we give the following list of metals whose salts may be used in
the manner described above:
Aluminium barium, bismuth, calcium, cobalt chromium cadmium, copper, iron
(both as ferrous and ferric) lead mercury (mercurous and mercuric) magnesium,
manganese, nickel, potassium, silver, sodium, strontium, tin, zinc, and also
ammonium.
As many of the salts of beta-sulpho-naphthalene obtained from the above metals
are only slightly soluble in water, nearly the whole of the beta-sulpho-naphthalene
in the melt may be obtained direct in the form of one of these salts.
For example the iron salt (ferrous) crystallising with six molecules of water is
only soluble to the extent of about 0-5 in 100 at the ordinary temperature and the

page_text: magnesium salt crystallising with six molecules of water is only soluble to the
extent of 0.5 to 0.75% in 100 at the ordinary temperature.
As an example of the reaction we give that of the sulphate of iron (ferrous
sulphate) and beta-sulpho-naphthalene which may be expressed by the following
equation.
+H₂SO
The process for the separation of the alpha and the beta-sulpho-naphthalene is
based upon the reaction as described above.
When naphthalene is sulphonated with strong sulphuric acid both the alpha
acid and the beta modifications of the mono-sulpho acid are formed, but in varying
proportions according to the temperature at which the operation is worked.
Now if to the diluted melt there is added a solution of one of the salts of the
above mentioned metals, there will be obtained as a crystalline precipitate the salt
of nearly the whole of the beta-sulpho-naphthalene present, and if we employ a
salt the metal of which forms only a very slightly soluble salt with beta-sulpho-
naphthalene, then we remove all but traces of beta-sulpho-naphthalene from the
solution; such a metal is, for example, iron whose salt (ferrous) with beta-sulpho-
naphthalene and containing six molecules of water of crystallisation, is only soluble
to the extent of about 0-5 parts in 100 parts of cold water.
Where practicable, we prefer to use the sulphates of the metals as the sulphuric
acid liberated by the reaction goes only to increase the amount of free sulphuric acid
already present, whereas if other salts such as chlorides were used the acids liberated
would prove more difficult to deal with. Of course, in many cases it might be
advantageous to use the carbonates of the above metals.
Although many of the above mentioned metals would serve the purpose, we will
by way of example proceed to describe the use of iron in putting into practice this
process, for example, with crude sulpho-naphthalene.
After making crude sulpho-naphthalene from naphthalene and sulphuric acid in
the manner well known to manufacturers, we dilute the melt with say five times its
bulk of water, or even less, and allow it to stand till cold; we then filter to
separate any unconverted naphthalene.
To this solution we then add with constant stirring a concentrated solution of
iron sulphate (ferrous sulphate) testing from time to time as the iron sulphate is
being added and we stop the addition when no further precipitate takes place
on adding a drop of iron sulphate solution to a small portion of the mixture which
has been filtered into a test glass.
When this point is reached we know that we have added sufficient iron sulphate
to produce the iron salt of all the beta-sulpho-naphthalene present.
After standing some time to allow all the iron salt, which will separate, to do so,
we filter the mixture by any convenient means and we free the precipitate from
the mother liquor remaining, by spinuing in a centrifugal machine and washing
with water or by any other convenient process.
The solid portion now being free from the impurities contained in the mother
liquor, and consisting of the iron salt of nearly pure beta-sulpho-naphthalene, we
dissolve in or mix with boiling water and add thereto carbonate of sodium¸ until all
the iron is precipitated in the form of carbonate and the sodium has taken the
place of the iron in combination with the beta-sulpho-naphthalene.
The precipitated carbonate of iron is filtered off and washed with water and the
mother liquor and washings are put together and treated according to the
destination of the sodium salt of the beta-sulpho-naphthalene.
The sodium salt is the form which is required for the manufacture of beta-sulpho-
naphthalene.

page_text: The iron carbonate obtained as above may be used for making further iron salt
of beta-sulpho-naphthalene either by adding direct to the diluted melt, warming if
necessary, or it may be dissolved in sulphuric acid and so converted again into
sulphate of iron.
The original mother liquor (from the treated melt) and the washings from
the precipitate may be used for diluting a fresh melt or may be directly
neutralised with milk of lime and the alpha-sulpho-naphthalene recovered therefrom
in the form of the calcium salt in the manner usually employed; that is, by
filtering to separate the sulphate of lime formed and evaporation and crystallisation
of the liquor to obtain the salt of alpha-sulpho-naphthalene. In the case where
much alpha-sulpho-naphthalene is present in the melt, we prefer to neutralise at
once after the separation of the beta salt, but where only small quantities are
present, we prefer to use the mother liquor for diluting a fresh melt and finally
if necessary concentrating the mother liquor by evaporation.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, we declare that what we
claim is
1. Producing salts of beta-sulpho-naphthalene from an acid solution containing
beta-sulpho-naphthalene, by adding to a diluted solution hereof the salt of a
metal whereby the beta-sulpho-naphthalene is precipitated in the form of a
crystalline salt, substantially as described.
2. Separating the alpha- and beta-sulpho-naphthalenes of an acid solution
containing both alpha- and beta-sulpho-naphthalene, by adding the salt of a metal
to a diluted solution, whereby the beta-sulpho-naphthalene is precipitated. in the
form of a crystalline salt, while the alpha-sulpho-naphthalene remains in solution
in the mother liquor, from which it is recovered by known means, substantially
as described.
Dated this 1et day of December 1201
ABEL & IMRAY,
Agents for the Applicant.