AN IMPROVED PROCESS FOR THE MANUFACTURE OF VANILLIN
Year: 1880

page_text: LETTERS PATENT to William Robert Lake, of the Firm of Haseltine, Lake,
& Co., Patent Agents, Southampton Buildings, London, for an Invention of
"AN IMPROVED PROCESS FOR THE MANUFACTURE OF VANILLIN." A com-
munication from abroad by Anton Meissner, of Olmuetz, Moravia, in the
Empire of Austria.
PROVISIONAL SPECIFICATION left by the said William Robert Lako at the
Office of the Commissioners of Patents on the 19th June 1880.
WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, & Co., Patent Agents,
Southampton Buildings, London. "AN IMPROVED PROCESS FOR THE MANUFACTURE
OF VANILLIN." [A communication from abroad by Anton Meissner, of Olmuetz,
Moravia, in the Empire of Austria.]
The present new or improved process for the manufacture of vanillin, that is to
say, the aromatic principle or element of vanilla, consists in producing the vanillin
from eugenol C, H, O by first forming aceteugenol, then oxidizing the accteu-
genol with a certain proportion of permanganate of potash in a neutral solution, and
finally further oxidizing the product with chromate of potash in a neutral solution.
In order that the said Invention may be clearly understood, I will now proceed
to describe the manner of carrying the same into practice, that is to say:-
The aceteugenol is obtained by digesting dry eugenol C, H, O; with an excess
of acetylchloride C₂, H, O Cl. The excess of acetylchlorido is distilled off, and the
last remnants removed by passing a current of dry air through the mass.
crude aceteugenol thus obtained is used for the production of the vanillin.
The
The process for the production of the vanillin from this aceteugenol consists
preferably of two operations as follows:—
First operation. The crude aceteugenol is oxidized in neutral solution by means
of a solution of two and a half parts by weight of permanganate of potash in one
hundred parts by weight of water. The proportion, in which the permanganate of
potash Ka, Mn, O, is allowed to act on the aceteugenol, is twenty parts by weight
of accteugenol to from forty seven to fifty parts by weight of permanganate of

page_text: potash, the proportionato quantity of permanganate of potash Ka, Mn, Os
depending upon the degree of purity of the crude aceteugenol. To determine the
correct proportions, it is always necessary to make some preliminary experiments
with small quantities of the crudo aceteugenol.
The oxidation of the aceteugenol by means of permanganate of potash is effected
in the following manner, that is to say-Twenty five to thirty grammes of
aceteugenol, of a temperature of 40 degrees centigrade or 104 degrees Fahrenheit,
are put into a square bottle holding about four or five litres, and the sides of which
are half as broad as they are long and high. Proviously a quarter of a litre of
water, of the temperature of from 30 to 35 degrees centigrade or 86 to 95 degrees
Fahrenheit, is put into the bottle. The bottle thus containing a mixture of
aceteugenol and water is now kept in constant agitation by any suitable apparatus,
such as a table having a fixed stand and a movable table plate, which is kept in
constant oscillation by any suitable mechanical means. The number of oscillations
of the table plate may be from eighty to one hundred per minute. The angular
shape of the bottle and the rapid oscillations of the table plate, cause the particles
of the aceteugenol to be thoroughly mixed with the water.
The mixing having been sufficiently effected, which may be in about a minute,
the solution of permanganate of potash, which may have a temperature of from
30 to 35 degrees centigrade or 86 to 95 degrees Fahrenheit, is gradually added.
The time occupied by the addition of this oxidizing solution is so regulated that
it will be completed in from 20 to 25 minutes, and the table upon which there
may be about twenty bottles at a time must be kept in motion as long as the
oxidizing process lasts.
The product obtained is now separated by means of a press-filter from the
binoxide of manganese formed during the oxidation, and after decomposing the
small quantity of carbonate of potash by means of sulphuric acid the clear liquid
is evaporated under vacuum at a temperature of from 50 to 60 degrees centigrado
or 122 to 140 degrees Fahrenheit, to about one fifteenth or one twentieth of its
original volume.
From the concentrated lye thus obtained the acetvanillin formed during the
oxidizing process is extracted by repeated agitation with ether.
Second Operation.-The lye freed from the acetvanillin is heated in suitable
apparatus up to 100 degrees centigrade or 212 degrees Fahrenheit, in order to
remove all the ether yet remaining in the solution. When this is donc, the lye,
if acid, is carefully neutralized, and then mixed with neutral chromate of potash.
This mixing is effected in the proportion of five parts by weight of bichromate,
of potash Ka 2 Cr O, to a quantity of the product of oxidation corresponding to
about one hundred parts by weight of accteugenol. The mixture is now heated
either under the ordinary atmospheric pressure or under a higher pressuro, until
the chromate is entirely decomposed. Aftor this has been effected the product is
filtered off from the oxide of chromium formed by the decomposition of the
chromato, and then slightly acidified and shaken up with ether to remove tho acct-
vanillin formed during the oxidizing process.
The lye freed from acetvanillin is again submitted once or twice to the same
operation, except that in the second operation, only three parts by weight, and in
the third only two parts by weight of bichromate of potash are employed.
A simplification of these consecutive processes may be attained by mixing the
original lye freed from binoxide of manganese, or the evaporated lye with the
above-mentioned quantity of bichromate of potash without previously separating
it from the acetvanillin formed during the oxidizing process.
Should the bichromate of potash be added immediately to the original lye, then
the slight quantity of carbonate of potash present has to be previously decomposed,
after which the whole is evaporated under a vacuum, and as, in the second case,
heated as long as there is any undecomposed chromate still present.
The oxidation, with bichromate of potash, must be carried out only in neutral
solution.

page_text: In both cases the acetvanillin formed is shaken up with ether, and boiled with
lye of soda after the ether has been distilled off.
By thus decomposing the acctvanillin by means of the lye of soda crude vanillin
is obtained, which is purified by being dissolved in ether and shaken up with a
warm saturated solution of bisulphite of soda Na, 2SO,
The bisulphite solution containing all the vanillin is put aside in a cool place,
where it soon solidifies to a crystalline mass. The crystals are now separated from
the mother lye, then washed in a concentrated solution of bisulphite of soda, and
finally in strong alcohol.
The double compound thus purified is finally decomposed with sulphuric
acid H. SO, whereupon the vanillin separates in the form of a colorless oil, and
can be finally recrystallized in water.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Robert Lake in the Great Seal Patent Office on the 18th
December 1880.
WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, & Co., Patent Agents,
Southampton Buildings, London. "AN IMPROVED PROCESS FOR THE MANUFACTURE
OF VANILLIN." A communication from abroad by Anton Meissner, of Olmuetz,
Moravia, in the Empire of Austria.
The present new or improved process for the manufacture of vanillin, that is to
say, the aromatic principle or element of vanilla consists in producing the vanillin
from eugenol CH, O, by first forming acctcugenol, then oxidizing the aceteu-
genol with a certain proportion of permangate of potash in a neutral solution, and
finally further oxidizing the product with bichromate of potash in a neutral solution.
In order that the said Invention may be clearly understood I will now proceed to
describe the manner of carrying the same into practice, that is to say :-
The aceteugenol is obtained by digesting dry eugenol C, H, O, with an excess
of acetychloride C, H, O Cl. The excess of acetylchloride is distilled off, and the
last remnants removed by passing a current of dry air through the mass. The
crude aceteugenol thus obtained is used for the production of the vanillin.
The process for the production of the vanillin from this aceteugenol consists
preferably of two operations as follows:-
First Operation. The crude aceteugenol is oxidized in a neutral solution by
means of a solution of two and a half parts by weight of permanganate of potash
in one hundred parts by weight of water. The proportion, in which the perman-
ganate of potash K, Mn, O, is allowed to act on the aceteugenol, is twenty parts
by weight of aceteugenol to from forty seven to fifty parts by weight of per-
manganate of potash, the proportionate quantity of permanganate of potash
K, Mn, O, depending upon the degree of purity of the crude aceteugenol. To
determine the correct proportions, it is always necessary to make some preliminary
experiments with small quantities of the crude aceteugenol.
The oxidation of the aceteugenol by means of permanganate of potash is effected
in the following manner, that is to say-Twenty five to thirty grammes of
aceteugenol of a temperature of 40 degrees centigrade or 104 degrees Fahrenheit
are put into a square bottle holding about four or five litres, and the sides of which
are half as broad as they are long. Previously a quarter of a litre of water of the
temperature of from 30 to 35 degrees centigrade or 86 to 95 degrees Fahrenheit is
put into the bottle. The bottle thus containing a mixture of aceteugenol and
water is now kept in constant agitation by any suitable apparatus, such as a table
having a fixed stand and a movable table plate, which is kept in constant oscillation
by any suitable mechanical means. The number of oscillations of the table plate
may be from eighty to one hundred per minute. The angular shape of the bottle
and the rapid oscillations of the table plate, cause the particles of the aceteugenol
to be thorougly mixed with the water.
The mixing having been sufficiently effected, which may be in about a minute,
the solution of permanganate of potash, which may have a temperature of from 30
to 35 degrees centigrade or 86 to 95 degrees Fahrenheit, is gradually added.
The time occupied by the addition of this oxidizing solution is so regulated that
it will be completed in from 20 to 25 minutes, and the table upon which there
may be about twenty bottles at a time must be kept in motion as long as the
oxidizing process lasts.
The product obtained is now separated by means of a filter-press from the
binoxide of manganese formed during the oxidation, and after decomposing the
small quantity of carbonate of potash by means of sulphuric acid the clear liquid
is evaporated in a vacuum at a temperature of from 50 to 60 degrees centigrade,
or 122 to 140 degrees Fahrenheit, to about one fifteenth or one twentieth of its
original volume.

page_text: From the concentrated lye thus obtained the acetvanillin formed during the
oxidizing process is extracted by repeated agitation with ether.
Second Operation.-The lye freed from the acetvanillin.is heated in suitable
apparatus up to 100 degrees centigrade, or 212 degrees Fahrenheit, in order to
remove all the ether still remaining in the solution. When this is done tho lye,
if acid, is carefully neutralized and then mixed with neutral chromate of
potash.
-
This mixing may be effected in the proportion of five parts by weight of
bichromate of potash K, Cr, O, to a quantity of the product of oxidation corro-
sponding to about one hundred parts by, weight of aceteugenol. The mixture is
now.heated either under the' ordinary atmospheric pressure or under a higher
pressure until the chromato is entirely decomposed. After this has been effected
the product is filtered off from the oxide of chromium formed by the decomposition
of the chromate, and then slightly acidified and shaken up with ether to removo
tho acetvanillin formed during the oxidizing process.
"
The lye freed from acotvanillin is again submitted once or twice to the same
operation, except that, in the second operation, only three parts by weight and,
in the third, only two parts by weight of bichromate of potash are employed.
A simplification of these consecutive processes may be attained by mixing the
original lye freed from binoxide of manganese, or the evaporated lye with the
above-mentioned quantity of bichromate of potash without previously separating
it from the acetvanillin formed during the oxidizing process.
Should the bichromate of potash be added immediately to the original.lye, the
slight quantity of carbonate of potash present has to be previously decomposed,
after which the whole is ovaporated in a vacuum, and, as in the second case, heated
as long as there is any undecomposed chromato still present.
The oxidation with bichromate of potash must be carried out only in a neutral
solution.
In both cases the acetvanillin formed is shaken up with ether, and boiled with
lye of soda after the ether has been distilled off..
By thus decomposing the acetvanillin by means of the lye of soda crude vanillin
is obtained, which is purified by being dissolved in ether, and shaken up with a
warm saturated solution of bisulphite of soda Na 'H SO.
·
The bisulphite solution containing all the vanillin is put aside in a cool placo,
where it soon solidifies to a crystallino mass. The crystals are now separated from
the mother lye, then washed in a concentrated solution of bisulphite of soda, and
finally in strong alcohol.
The double compound thus purified is finally decomposed with sulphuric acid
H. SO, whereupon the vanillin separates in the form of a colorless oil and can be
finally recrystallized in water.
Having thus fully described the said Invention, as communicated to me by my.
foreign correspondent, and the manner of performing the same, I wish it understood
that I claim,
The above described process of manufacturing vanillin from ougenol by first
forming aceteugenol, then oxidizing the aceteugenol with permanganate of potash
in a neutral solution, and finally further oxidizing the product with bichromate of
potash in a neutral solution.
-
"
In witness whereof, I, the said William Robert Lako, have hereunto set my
band and meal this Dighteenth dair of December in the year of our Lord