Improvement in Extracting Sugar from Molasses by Means of Barium Hydroxysulphide, and Recovering the latter.
Year: 1896

page_text: Date of Application, 24th July 1896
Complete Specification Left, 23rd Mar., 1897-Accepted, 5th June, 189?
Improvement in Extracting Sugar from Molasses by Means of
Barium Hydroxysulphide, and Recovering the latter.
I, WALTHER FELD of Hönningen a/Rhein, in den Silven, in the German
Empire, Chemist, do hereby declare the nature of this invention to be as
follows:-
In extracting sugar from molasses continuously by means of barium hydroxy-
sulphide alone this substance is mixed with the molasses; the solution is separated
from the precipitated barium saccharate, the residual liquid, containing harium
sulphhydrate, is treated with carbonic acid, or in a special way with sulphite or
sulphate of. magnesia; the sulphuretted hydrogen thus produced is burned to form
sulphurous or sulphuric acid; and these compounds are employed to decompose
the barium saccharate that was precipitated during the operation of extracting the
sugar. In this manner a solution of sugar, and also sulphite or sulphate of barium
are produced, which are then converted by reduction effected by heating to incan-
descence, with carbonaceous matter into sulphide of barium. By treating this
sulphide with water, barium hydroxy-sulphide is reproduced, which is again
employed to separate the sugar from the molasses.
This process has the disadvantage that, in order to precipitate the sugar from
molasses in the form of barium saccharate, only half of the barium introduced in
the form of barium hydroxysulphide is utilised, whilst the other half passes into
the residual liquid, from which it has to be recovered.
The present invention relates to means of obviating this disadvantage and
consists in precipitating the sugar contained in the molasses, not by means of
barium hydroxysulphide alone, but by using for this purpose a mixture of
barium bydroxysulphide Ba(SH)(OH) with an equivalent quantity of sodium
hydroxide NaOH, or of potassium hydroxide KOH, or of a mixture of these.
On allowing barium hydroxysulphide and caustic potash to act simultaneously or
successively upon a solution of sugar, there are formed insoluble barium saccharate
and hydrated sulphide of alkali. This reaction is represented by the following
cavations.

page_text: If the mixture of barium hydroxysulphide with caustic alkali is not to be
employed to precipitate the sugar, the sugar can be precipitated from the
molasses by means of barium hydroxysulphide, and then the alkali can be added.
In this case, the reaction takes place in two stages which may be represented by
the following equations :-
Бал),
Barium bydrosulphide + potassium hydroxide = barium hydroxide +
+
2 KHS
+ Potassium sulphydrate.
==
The barium hydroxide set free in the second stage of the reaction then acts
upon a fresh molecule of sugar, so that the result of the reaction is really the same
as when barium-hydroxysulphide and caustic alkali are employed together to
precipitate the sugar.
The process is carried out in the following manner :-
The molasses are mixed with a mixture of barium hydroxysulphide and caustic
alkali either in the solid form or as a solution of any desired concentration at
temperatures between 60° and 100° C. The quantity of the reagent employed
for precipitation depends on the previously determined percentage of sugar in the
solution.
To 342 parts of sugar, there are employed about 187 parts of barium
hydroxysulphide and 56 parts of potassium hydroxide, or 40 parts of sodium
hydroxide. The precipitated barium saccharate is separated by filtration &c.,
from the liquid, is washed, and after suspension in water or in a solution of sugar,
is decomposed by means of the sulphurous acid or sulphuric acid obtained in
another stage of the process. In these operations, there is produced in one
case a solution of sugar, and in the other case barium sulphite or sulphate.
The sulphurous acid can be used in the gaseous state or in the form of a
solution.
The sulphuric acid may be employed in any desired degree of concentration.
The amount of the sulphurous acid or of the sulphuric acid depends on the
quantity of the barium saccharate to be decomposed, because one molecule of
sulphurous acid or of sulphuric acid is required to decompose one molecule of
barium saccharate, according to the equation:-

page_text: The decomposition of the barium saccharate may also be effected by means of
carbonic acid, in which case however the barium carbonate formed must be
converted into barium sulphite by a subsequent treatment with sulphurous acid.
The residual liquid, remaining after precipitation of the sugar as barium
saccharate, is treated with carbonic acid, whereby sulphuretted hydrogen is
liberated according to the equation :-
The treatment of the liquid with carbonic acid may be effected either at the
ordinary temperature, or at a higher temperature, but the actual expulsion of the
sulphuretted hydrogen takes place only with application of heat. The generated
sulphuretted hydrogen is converted into sulphurous acid by burning according to
kuown methods. Instead of sulphurous acid, sulphuric acid also may be produced.
Both compounds are employed to decompose the barium saccharate, so that either
barium sulphite or barium sulphate is produced, these substances being then
converted by means of incandescent carbonaceous matter into barium sulphide
which by treatment with water produces barium hydroxysulphide. This is again
used to extract sugar from molasses. Thus the process becomes continuous the
reagent employed for extraction being continually regenerated for subsequent use.
The mode of applying the carbonic acid for driving out the sulphuretted
hydrogen, differs according as the carbonic acid available is concentrated or highly
diluted. If the carbunic acid is sufficiently concentrated, it is made to act with
heating upon the residual liquid, until all the sulphuretted hydrogen is expelled.
But if the carbonic acid available is so dilute that it would yield sulphuretted
hydrogen by direct expulsion only in such a dilute state as to be incapable of being
burned to sulphurous acid, then only one half the sulphuretted hydrogen is
driven out directly by means of carbonic acid, and carbonic acid is continued to be
introduced in the cold until all the alkali carbonate is converted into bicarbonate.
Heat is then applied, and the reaction which takes place is expressed by the
following equation:-
Sulphuretted hydrogen.
As any desired amount of carbonised residue that is to say, alkali carbonate can
be added to the residual liquid, it is possible, even with highly dilute carbonic acid,
to maintain the sulphuretted hydrogen at any desired degree of concentration.
The added carbonised residue is recovered on calcining the residue.
On calcining the residual liquid the alkali carbonate is recovered at the same
time as the alkali which existed in the molasses.
For the purpose of further decomposing the barium sulphydrate, the requisite
part of carbonised residue is dissolved in water. So much caustic lime is added, as
is requisite for combining with or fixing the carbonic acid. The alkali solution
filtered off from the carbonate of lime; is introduced again into the cycle or
continuous process.
Dated this 24th day of July 1896
ABEL & IMRAY,
Agents for the Applicant.

page_text: Improvement in Extracting Sugar from Molasses by Means of
Barium Hydroxysulphide, and Recovering the latter.
I, WALTHER FELD, of Hönningen a/Rhein in den Silven, in the German
Empire, 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 :-
In extracting sugar from molasses continuously by means of barium hydroxy-
sulphide alone, this substance is mixed with the molasses; the solution is separated
from the precipitated barium saccharate, the residual liquid, containing barium
sulphhydrate, is treated with carbonic acid, or in a special way with sulphite or
sulphate of magnesia; the sulphuretted hydrogen thus produced is burned to form
sulphurous or sulphuric acid, aud these compounds are employed to decompose the
barium saccharate that was precipitated during the operation of extracting the
sugar. In this manner a solution of sugar, and also sulphite or sulphate of barium
are produced, which are then converted by reduction, effected by heating to
incandescence with carbonaceous matter, into sulphide of barium.
By treating
this sulphide with water, barium-hydroxysulphide is reproduced, which is again
employed to separate the sugar from molasses.
This process has the disadvantage that, in order to precipitate the sugar from
molasses in the form of barium saccharate, only half of the barium introduced in
the form of barium hydroxysulphide is utilised, whilst the other half passes into
the residual liquid, from which it has to be recovered.
The present invention relates to means of obviating this disadvantage and
consists in precipitating the sugar contained in the molasses, not by means of
barium hydroxysulphide alone, but by using for this purpose a mixture of barium
hydroxysulphide Ba(SH)(OH) with an equivalent quantity of sodium
hydroxide NaOH, or of potassium hydroxide KOH, or of a mixture of these. On
allowing barium hydroxy-sulphide and caustic potash to act simultaneously or
successively upon a solution of sugar, there are formed insoluble barium saccharate
and hydrated sulphide of alkali. This reaction is represented by the following
equation:-

page_text: by means of barium hydroxysulphide, and then the alkali can be added.
case, the reaction takes place in two stages which may be represented by the
following equations :-
2 Ba(OH)(SH)
Barium hydroxysulphide
Ba(SH),
+ C₁₂O₁
sugar
Barium hydrosulphide
+ H₂O
BOCHO
barium saccharate
water
+
The barium hydroxide set free in the second stage of the reaction then acts upon
a fresh molecule of sugar, so that the result of the reaction is really the same as
when barium hydroxysulphide and caustic alkali are employed together to
precipitate the sugar.
The process is carried out in the following manner.
The molasses are mixed with a mixture of barium hydroxysulphide and caustic
alkali either in the solid form or as a solution of any desired concentration at
temperatures between 60° and 100° C. The quantity of the reagent employed for
precipitation depends on the previously determined percentage of sugar in the
solution. To 312 parts of sugar, there are employed about 187 parts of barium
hydroxysulphide and 56 parts of potassium hydroxide, or 40 parts of sodium
hydroxide. The precipitated barium saccharate is separated by filtration, &c.,
from the liquid, is washed, and, after suspension in water or in a solution of sugar,
is decomposed by means of the sulphurous acid or sulphuric acid obtained in
another stage of the process. In these operations, there is produced in one case a
solution of sugar, and in the other case barium sulphite or sulphate. The
sulphurous acid can be used in the gaseous state or in the form of a solution.
The sulphuric acid may be employed in any desired degree of concentration. The
amount of the sulphurous acid-or of the sulphuric acid-depends on the quantity
of the barium saccharate to be decomposed, because one molecule of sulphurous
acid or of sulphuric acid is required to decompose one molecule of barium
saccharate, according to the equation:-

page_text: The residual liquid, remaining after precipitation of the sugar as barium
saccharate, is treated with carbonic acid, whereby sulphuretted hydrogen is liberated
according to the equation:-
Potassium carbonate
sulphuretted hydrogen.
The treatment of the liquid with carbonic acid may be effected either at the
ordinary temperature, or at a higher temperature, but the actual expulsion of the
sulphuretted hydrogen takes place only with application of heat. The generated
sulphuretted hydrogen is converted into sulphurous acid by burning according to
known methods. Instead of sulphurous acid, sulphuric acid also inay be produced.
Both compounds are employed to decompose the barium saccharate, so that either
barium sulphite or barium sulphate is produced, these substances being then
converted by means of incandescent carbonaceous matter into barium sulphide which,
by treatment with water, produces barium hydroxyзulphide. This is again used to
extract sugar from molasses. Thus the process becomes continuous, the reagent
employed for extraction being continually regenerated for subsequent use.
The mode of applying the carbonic acid for driving out the sulphuretted hydrogen
differs according as the carbonic acid available is concentrated or highly diluted.
If the carbonic acid is sufficiently concentrated, it is made to act with heating upon
the residual liquid, until all the sulphuretted hydrogen is expelled. But if the
carbonic acid available is so dilute that it would yield sulphuretted hydrogen by
direct expulsion only in such a dilute state as to be incapable of being burned
to sulphurous acid, then only one half the sulphuretted hydrogen is driven out
directly by means of carbonic acid, and carbonic acid is continued to be introduced
in the cold until all the alkali carbonate is converted into bicarbonate. Heat
is then applied, and the reaction which takes place is expressed by the following
equation:-
Acid potassium carbonate
KHCO3
+
KHS
potassium sulphydrate
K,CO3
+
H₂S
Potassium carbonate
sulphuretted hydrogen.
As any desired amount of carbonised residue, that is to say, alkali carbonate,
can be added to the residual liquid, it is possible, even with highly dilute
carbonic acid, to maintain the sulphuretted hydrogen at any desired degree
of concentration. The added carbonised residue is recovered on calcining the
residue.
On calcining the residual liquid the alkali carbonate is recovered at the same
time as the alkali which existed in the molasses.
For the purpose of further decomposing the barium sulphhydrate, the requisite
part of carbonised residue is dissolved in water. So much caustic lime is added, as
is requisite for combining with or fixing the carbonic acid. The alkali solution
filtered off from the carbonate of lime is introduced again into the cycle or
continuous process.
Having now particularly described and ascertained the nature of my said inven-
tion and the manner in which the same is to be performed I declare that what I
claim is :-
The herein described process for extracting sugar from molasses by precipitating
the sugar with a mixture of barium hydroxysulphide and alkali hydroxide or by

page_text: treating the molasses first with barium hydroxysulphide and then with alkali-
hydroxide, recovering the alkali hydroxide from the carbonised residue in the
form of alkali carbonate, thus utilizing the whole of the added baryta for
extracting the sugar, also separating the sulphuretted hydrogen from the
residual liquid containing alkali sulphhydrate by means of carbonic acid or
alkali carbonate with carbonic acid, and again converting the carbonised residue
by means of caustic lime into alkali hydroxide to be used again for extracting
sugar.
ABEL & IMRAY,
Agents for the Applicant.