Process for the Manufacture of Vanilline from Isoeugenol and Eugenol.
Year: 1896

page_text: Date of Application. 6th July, 1896
Complete Specification Left, 31s Mar., 1897-Accepted, 29th May, 1807
[Communicated from abroad by the Firm HAARMANN AND REIMER, of
Holzminden, Germany.]
Process for the Manufacture of Vanilline from Isoeugenol and
Eugenol.
.
I, HAROLD IMRAY, of No. 28, Southampton Buildings, Chancery Lane, in
the County of London, Chartered Patent Agent, do hereby declare the nature
of this invention to be as follows:-
It was described in the Sperification No. 11952 of 1894, that isoeugenol is
oxidised directly to vanilline by heating it with addition of a sufficient quantity of
water in the presence of alkalies or alkali hydrates along with peroxides, such as
peroxide of sodium, peroxide of hydrogen, peroxide of barium, peroxide of lead or
peroxide of manganese.
Also permanganate and manganate of potassium, which give off oxygen in a
strong alkaline solution, in the presence of large quantities of alkali hydrates in
excess produce vanillin directly from isoeugenol. Further quantities of vanillin
are formed in these cases by the reciprocal action which takes place with the
alkali-hydrates in excess, between the simultaneously produced hydrated peroxide
of manganese and the non decomposed isoeugenol.
In this process eugenol may be substituted for isoengenol, if the eugenol is
converted previously by heating it in the presence of alkali-hydrates and water, or
was described. in De Laire's
of alcohol, into an alkali-salt of isoeugenol, as
Specification No. 17547 of 1890.
In this case it is not necessary to separate the isoeugenol.
By oxidising eugenol directly with permanganate of potassium according to
Erlenmeyer (Berichte der Deutschen Chemischen Gesellschaft, IX, p. 273) only
traces of vanilline are produced.
When Erlenmeyer's experiments were made, isoeugenol had not been
discovered.
The following process differs from the process described in the Specification
No. 11952 of 1894 only by the conditions of operating, which exercise an
important influence on the chemical reactions and on the resulting quantities of
vanilline.
The new process is conducted in the following manner:
10 parts of isoeugenol are dissolved in from 250 to 400 parts of soda-lye of
8 per cent. strength and the solution is heated to the boiling point:
About 80 parts of peroxide of sodium are slaked in the most careful manner
with as little ice as possible so as to form a stiff paste of hydrated peroxide of
sodium.
The latter is added in small portions to the boiling alkaline solution of isoeugenol-
sodium and the heating of the alkaline solution is continued for about three quarters
of an hour.
After the alkaline solution has entirely ceased to foam, it is cooled and acidulated
with sulphuric acid, and raw vanilline is extracted by means of ether or other
uitable solvent

page_text: From the raw vanilline thus isolated pure vanilline is obtained by known
methods.
In the above described process, for hydrated peroxide of sodium may be partially
or entirely substituted peroxide of hydrogen, hydrated peroxide of barium, peroxide
of manganese, peroxide of lead, and for the alkali-hydrate may be partially
substituted earth-alkali-hydrate.
In using, instead of peroxide of sodium, larger quantities of the other peroxides
and in particular of the insoluble peroxides, such as peroxide of manganese or
peroxide of lead, heat must be applied for a long time in order to obtain
satisfactory output of vanilline.
The above described process may be modified by mixing, at once in the cold,
with the aqueous solution of isoeugenol-sodium the whole quantity of hydrated
peroxide of sodium to be used for oxidation, and heating the mixture cautiously by
means of a steam-coil, or by introducing steam in such a manner that a violent
evolution of large quantities of oxygen cannot take place.
Dated 6th day of July 1896.
ABEL & IMRAY,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Process for the Manufacture of Vanilline from Isoeugenol and
Eugenol.
I, HAROLD IMRAY, of No. 28 Southampton Buildings, Chancery Lane, in the
County of London, Chartered Patent Agent, 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 :-
It was described in the Specification No. 11952 of 1894, that isoeugenol is
oxidised directly to vanilline by heating it with addition of a sufficient quantity of
water in the presence of alkalies or alkali hydrates along with peroxides, such as
peroxide of sodium, peroxide of hydrogen, peroxide of barium, peroxide of lead, or
peroxide of manganese.
Also permanganate and manganate of potassium, which give off oxygen in a
strong alkaline solution, in the presence of large quantities of alkali hydrates in
excess produce vanilline directly from isoeugenol. Further quantities of vanilin
are formed in these cases by the reciprocal action which takes place with the alkali-
hydrates in excess between the simultaneously produced hydrated peroxide of
manganese and the non decomposed isoeugenol.
In this process eugenol may be substituted for isoeugenol, if the eugenol is
converted previously by heating it in the presence of alkali-hydrates and water, or
of alcohol, into an alkali-salt of isoeugenol, as was described in De Laire's
Specification No. 17,547 of 1890.
In this case it is not necessary to separate the isoeugenol.
By oxidising eugenol directly with permanganate of potassium according to
Erlenmeyer (Berichte der Deutschen Chemischen Gesellschaft, IX, p. 273) only
traces of vanilline are produced.
When Erlenmeyer's experiments were made, isoeugenol had not been
discovered.
The following process differs from the process described in the Specification
No. 11952 of 1894 only by the conditions of operating, which exercise an
important influence on the chemical reactions and on the resulting quantities of
vanilline.

page_text: The new process is conducted in the following manner.
10 parts of isoeugenol are dissolved in from 250 to 400 parts of soda-lye of
8 per cent. strength and the solution is heated to the boiling point.
About 80 parts of peroxide of sodium are slaked in the most careful manner
with as little ice as possible so as to form a stiff paste of hydrated peroxide of
sodium.
The latter is added in small portions to the boiling alkaline solution of isoeugenol-
sodium and the heating of the alkaline solution is continued for about three quarters
of an hour..
After the alkaline solution has entirely ceased to foam, it is cooled and acidulated
with sulphuric acid, and raw vanilline is extracted by means of ether or other
suitable solvent.
From the raw vanilline thus isolated pure vanilline is obtained by known
methods.
In the above described process, for hydrated peroxide of sodium may be partially
or entirely substituted peroxide of hydrogen, hydrated peroxide of barium, peroxide
of manganese, peroxide of lead and for the alkali-hydrate may be partially
substituted earth-alkali-hydrate.
In using, instead of peroxide of sodium, larger quantities of the other peroxides
and in particular of the insoluble peroxides, such as peroxide of manganese or
peroxide of lead, heat must be applied for a long time in order to obtain satisfactory
output of vanilline.
The above described process may be modified by mixing, at once in the cold,
with the aqueous solution of isceugenol-sodium the whole quantity of hydrated
peroxide of sodium to be used for oxidation, and heating the mixture cautiously by
means of a steam-coil, or by introducing steam in such a manner that a violent
evolution of large quantities of oxygen cannot take place.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. In the manufacture of vanilline from isoeugenol, the process of oxidising to
vanilline an alkaline solution of isoeugenol by means of peroxides or other com-
pounds giving off oxygen in alkaline solution, in the presence of alkali-hydrates or
earth-alkali-hydrates in excess, substantially as described.
2. A process for the direct manufacture of vanilline from eugenol consisting in
converting eugenol into an alkali-salt of isoeugenol in the manner described in the
Specification to Laire's Patent No. 17547 of 1890, and then oxidising directly to
vanilline a solution of the said raw salt by means of peroxides in the presence of
alkali-hydrate or of earth alkali hydrate substantially as described.
Dated this 21st der of March 1907
ABEL & IMRAY,
Agents for the Applicant.