Improvements in the Manufacture of Vanillin.
Year: 1896

page_text: PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Vanillin.
A communication from abroad by LA SOCIÉTÉ CHIMIQUE DES USINES DU RHÔNE,
anciennement, GILLIARD P. MONNET ET CARTIER, of Lyons, France,
Manufacturers.
I, GEORGE BELOE ELLIS of the firm of J. C. Mewburn & Ellis of 55 and
56 Chancery Lane in the County of London, Chartered Patent Agents, do hereby
declare the nature of this invention to be as follows:-
This invention relates to the manufacture of vanillin and has for its object the
purification of vanillin from its isomeride meta-methoxy-salicylic aldehyde.
Tiemann and Koppe have recommended (Berichte der deutschen chemische
Gesellschaft, 1881, p. 2021) the separation of meta-methoxy-salicylic aldehyde from
vanillin by means of distillation with steam, but at the same time they state that
they have encountered great difficulties in the process.
My correspondents have discovered that a complete separation of the two isomerides
above mentioned can be obtained by submitting the mixture to treatment with
calcium hydroxide held in suspension in water. The calcium hydroxide can be
replaced by the hydroxides of barium and strontium or by the oxides of magnesium
and zinc, but not so successfully.
To carry the invention into effect, one kilo. of the mixture of vanillin and meta-
methoxy-salicylic aldehyde may be dissolved in ether and poured into about 100 litres
of milk of lime containing half a kilo. of calcium hydroxide held in suspension by
means of an agitator. The vanillin dissolves in the alkaline solution whilst the
calcium salt of meta-methoxy-salicylic aldehyde is deposited in the form of a yellow
precipitate. After a little while the solution may be separated from the precipitate
by filtration, and the isomerides recovered from the solution and precipitate
respectively by acidulation and extraction with ether.
The amount of water used in the above operation may be varied according to the
larger or smaller quantity of vanillin in the mixture. The latter may also be dissolved
in other solvents than ether, such as ethylic or methylic alcohol.
J. C. MEWBURN & ELLIS,
55 and 56 Chancery Lane, London, Chartered Patent Agents.

page_text: COMPLETE SPECIFICATION.
Improvements in the Manufacture of Vanillin.
A communication from abroad by LA SOCIÉTÉ CHIMIQUE DES USINES DU RHONE,
anciennement GILLIARD P. MONNET ET CARTIER, of Lyons, France
Manufacturers.
I, GEORGE BELOE ELLIS of the firm of J. C. Mewburn & Ellis of 55 and
56 Chancery Lane in the County of London, Chartered Patent Agents, 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 vanillin and has for its object the
purification of vanillin from its isomeride, ineta-methoxy-salicylic aldehyde.
Tiemann and Kopp have recommended (Berichte der deutschen chemischen
Gesellschaft, 1881, page 2021) the separation of meta-methoxy-salicylic aldehyde from
vanillin by means of distillation with steam, but at the same time they state that they
have encountered great difficulties in the process.
My correspondents have discovered that a complete separation of the two isomerides
above mentioned can be obtained by submitting the mixture to treatment with
calcium hydroxide held in suspension in water, whereby the vanillin goes into
solution whilst the meta-methoxy-salicylic aldehyde is precipitated. The calcium
hydroxide may be replaced by the hydroxides of barium and strontium or by the
oxides of magnesium and zine, but not so successfully. For instance it has been
found by experimenting upon the pure isomeric aldehydes (not mixtures) under equal
conditions that when calcium hydroxide is employed the difference in solubility
between vanillin and ineta-methoxy-salicylic aldehyde is as 20 to 1, whilst with oxide
of magnesium it is only as 2 to 1. When mixtures of the aldehydes are treated with
calcium hydroxide and a proper quantity of water the vanillin may however be
brought into solution whilst scarcely any of the meta-methoxy-salicylic aldehyde is
dissolved, and thus a practically complete separation is effected.
To carry the invention into effect one kilo, of a mixture of vanillin and meta-
methoxy-calicylic aldehyde which is rich in vanillin may be dissolved in ether and
poured into about 100 litres of milk of lime containing half a kilo. of calcium
hydroxide held in suspension by means of an agitator. The vanillin dissolves in the
alkaline solution whilst the calcium salt of meta-methoxy-salicylic aldehyde is deposited
in the form of a yellow precipitate. After continuing the agitation for about one hour
the solution may be separated from the precipitate by filtration, and the isomerides
recovered from the solution and the precipitate respectively by acidulation and
extraction with ether, and the vanillin may then be purified in the usual way.
The amount of water used in the above operation may be varied according to the
larger or smaller quantity of vanillin in the mixture. The latter may also be dissolved
in other solvents than ether, such as ethylic or methylic alcohol.
Having now particularly described and ascertained the nature of the said invention
as communicated to me and in what manner the same is to be performed I declare
that what I claim is :-
The separation or purification of vanillin from a mixture of vanillin and meta
methoxy-salicylic aldehyde by submitting the mixture to treatment with calcium

page_text: hydroxide (or with barium hydroxide, strontium hydroxide, magnesium oxide, or zinc
oxide) in aqueous solution or suspension, then filtering, and then recovering the
vanillin dissolved out of the mixture, substantially as described.
Dated this 18th day of June 1897.
J. C. MEWBURN & ELLIS,
55 and 56 Chancery Lane, London, Chartered Patent Agents.