An Improved Process for the Production of Dihydroxytartaric Acid.
Year: 1897

page_text: Date of Application, 18th Nov., 1897
Complete Specification Left, 28th July, 1898-Accepted, 1st Oct., 1898.
PROVISIONAL SPECIFICATION.
An Improved Process for the Production of Dihydroxytartaric Acid.
We, HENRY JOHN HORSTMAN FENTON, M.A., of 7, Mortimer Road, Cambridge,
Demonstrator of Chemistry, and EDWARD SYDNEY ST. BARBE SLADEN, of 139,
Portsdown Road, Maida Vale, London, W., Gentleman, do hereby declare the
nature of this invention to be as follows:
This invention relates to the production of dihydroxytartaric acid, and consists
of a process by which this acid may be produced in a free and pure state with
ease and cheapness, the said product being a very valuable test for sodium, either
qualitatively or quantitatively, and being also, either as a free acid or in its salts,
a valuable adjunct in the preparation of tartrazin dyes by which the manufacture
of these dyes would be greatly facilitated.
To carry this process into effect the required acid is obtained from crystallized
dihydroxymaleic acid CHO, 2H, O, the preparation of which by the oxidation
of tartaric acid in the presence of iron was published by H. J. H. Fenton in the
Transactions of the Chemical Society, to whom also was communicated
some suggestions as to the production of dihydroxytartaric acid from the said
dihydroxymaleic acid, which suggestions were costly to carry out, and the free
acid could only be prepared indirectly and in relatively minute quantities.
It has been since discovered by the said H. J. H. Fenton, that the action of
bromine on dioxymaleic acid is a reversible one, and that certain conditions,
such as the free escape of hydrogen bromide, the careful addition of water, and
the maintenance of a low temperature, must be observed, to carry out the following
reaction with a good yield of free dihydroxytartaric acid.
The reaction we use is indicated thus:-
=
CHO+ 2H2O + Br₂ C,H,Os + 2HBr.
We grind the (solid) crystallized dihydroxymaleic acid with four times its
weight of liquid glacial acetic acid. Bromine is slowly added, and the reaction
The bromine and the water
is completed by the addition of a few drops of water.
must be added slightly in excess of the quantities indicated in the above equation.
The operation is performed in an open dish and at about 15° Centigrade.
By careful regulation of the amounts of acetic acid, water, and bromine, as
detailed above, we now find that from 70 to 80% of free dihydroxytartaric acid
can be separated out with ease and cheapness in a pure state without any
concentration.
The acid separates on stirring, and it is subsequently purified by washing with
ether, or with acetic acid, and by allowing it to stand in an exhausted receiver
over potash and sulphuric acid.
1007
FELL & JAMES,
1, Queen Victoria Street. London, E.C., Agents for the Applicants.

page_text: UVALT EVIM DITUITUATION.
An Improved Process for the Production of Dihydroxytartaric Acid.
We, HENRY JOHN HORSTMAN FENTON, M.A., of 7, Mortimer Road, Cambridge,
Demonstrator of Chemistry, and EDWARD SYDNEY ST. BARBE SLADEN, of 139,
Portsdown Road, Maida Vale, London, W., Gentleman, 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 production of dihydroxytartaric acid, and consists
of a process by which this acid may be produced in a free and pure state with
ease and comparative cheapness, the said product being a very valuable test for
sodium, either qualitatively or quantitatively, and being also, either as a free
acid, or in its salts, a valuable adjunct in the preparation of tartrazin dyes, by
which the manufacture of these dyes would be greatly facilitated.
To carry this process into effect the required acid is obtained from crystallized
dihydroxymaleic acid C,HO 2H2 O, the preparation of which by the oxidation
of tartaric acid in the presence of iron was published by H. J. H. Fenton in the
Transactions of the Chemical Society, to which Society also was communicated
some suggestions as to the production of dihydroxytartaric acid from the said
dihydroxymaleic acid, which suggestions were costly to carry out, and the free
acid could only be prepared indirectly and in relatively minute quantities.
It has been since discovered by the said H. J. H. Fenton that the action of
bromine on dihydroxymaleic acid is a reversible one, and that certain conditions,
such as the free escape of hydrogen bromide, the careful addition of water, and
the maintenance of a low temperature of about 15° Centigrade must be observed,
to carry out the following reaction with a good yield of free dihydroxytartaric acid.
The reaction we use is indicated thus:-
CHO + 2H2O + Br₂ = CHÃO¸ + 2HBr.
2
We grind the solid crystallized dihydroxymaelic acid with four times its weight
of liquid glacial acetic acid. Bromine dissolved in a little glacial acetic acid is
slowly added in small portions at a time. The first portions are almost instantly
bleached, but this action afterwards becomes sluggish and apparently ceases; a
few drops of water are then added, whereupon the colour of the bromine is again
immediately discharged. The addition of bromine is continued until the colour is
quite permanent on standing, and the reaction is completed by the addition of a
small quantity of water. The bromine and the water must be added slightly in
excess of the quantities indicated in the above equation.
The operation is performed in an open dish and at about 15° Centigrade.
By careful regulation of the amounts of acetic acid, water, and bromine, as
detailed above, we now find that from 70 to 80% of free dihydroxytartaric acid
can be separated out with ease and comparative cheapness, in a pure state without
any concentration.
The dihydroxymaleic is nearly insoluble in cold glacial acetic acid but when the
oxidation is finished complete solution takes place.
The solution is allowed to stand for an hour or two and is then vigourously
stirred when the dihydroxytartaric acid quickly, sometimes suddenly, separates,
as a heavy white crystalline powder, and it is subsequently purified by washing
with ether, or with acetic acid, and by allowing it to stand in an exhausted receiver
over solid caustic potash and sulphuric acid..
The product so obtained, when heated, melts sharply and decomposes at 114°—
115° C. The acid previously prepared by Miller's method melted and decom-
posed at 98° C.

page_text: By the production of dihydroxytartaric acid as before described, the production
of potassium and ammonium salts of this acid, which were hitherto unknown, is
facilitated. These salts are easily obtained from the acid by the action of
carbonates or acetates of potassium and ammonium, and are valuable as reagents
for the preparation of various derivatives of dihydroxytartaric acid; and the
potassium salt is especially valuable as a reagent for sodium, both for qualitative
and quantitative estimation.
The preparation of such dihydroxytartaric salts of potassium and ammonium
must be carried out as before stated at a low temperature, the solutions of both
the acid and ammonium and potassium salts being carefully cooled to 0°C.
before mixing.
And 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:-
-
1st. The production of dihydroxytartaric acid by the admixture of ground crystal-
lized dihydroxymaleic acid with four times its weight of liquid glacial acetic acid,
at a low temperature, in an open dish, and the addition thereto, gradually, of
bromine and water, drop by drop, slightly in excess of quantities hereinbefore
indicated and described by chemical formula.
2nd. The carrying out of reactions for the production and utilisation of
dihydroxytartaric acid at low temperatures from 0° to 15° Centigrade, substan-
tially as described.
1000
FELL & JAMES,
1, Queen Victoria Street, London, E.C., Agents for the Applicants.