A New or Improved Process for the Manufacture of Artificial Essence or Essential Oil of Violets.
Year: 1896

page_text: This Print is in accordance with the Original Specification as it stands after
Amendment (under Section 11 of the Patents, &c. Act, 1883), as required by
the decision of the Comptroller General of the 12th day of July, 1898.
Date of Application, 21st Nov., 1896
Complete Specification Left, 18th Aug., 1897-Accepted, 9th Oct., 1897
A New or Improved Process for the Manufacture of Artificial Essence
or Essential Oil of Violets.
A communication from FRANZ FRITZSCHE AND COMPANY of Hamburg-Uhlenhorst,
in the Empire of Germany.
I, ALFRED JULIUS BOULT, of 111, Hatton Garden, in the County of Middlesex,
Chartered Patent Agent, do hereby declare the nature of this invention to be as
follows:
The present invention relates to a process for the manufacture of artificial
essence or essential oil of violets and is chiefly remarkable for its great simplicity
and cheapness of production as well as for the cheapness of the raw materials
used. Hitherto artificial violet scent has been produced in the well-known manner
of condensing citral with acetone, whereupon aldehydes and ketones form under
the influence of alkalis or alkaline earths nev substances with formation of water;
the product thus obtained (Pseudo ionone) is converted by diluted mineral acid
into ionone. This process is costly and the amount yielded is very small.
The inventors came to the conclusion that the plants must use when producing
this scent-materials other than alkalis or alkaline earths and that perhaps com-
binations of iron played a part in it under the influence of light and oxygen.
Experiments have revealed the surprising fact that in the presence of substances
which with water yield oxygen, by cold or by hot process, a product of conden-
sation is obtained from citral or from oils containing citral and from acetone,
which product when boiled with weak oxidizing substances produces a volatile
oi having the fragrance of flowers.
The new and essential feature of the present invention consists in citral or oils
containing citral, and acetone being treated in diluted solution of alcohol with
such substances as usually have an oxidizing effect, but which in the present case
-probably owing to the temporary arrangement of atoms-protect or conduct
the reaction in the right direction-such substances as hypochlorite of alkalies or
alkaline earthis, as well as Barium peroxide can be used with advantage; the
invention further consists in the product so obtained being simultaneously con-
verted by means of weak oxidising substances into an oil having the fragrance
of violets and freed from impurities for this purpose chloride of iron or arsenic
acid may be used with advantage. The result attained is the more surprising
and remarkable since chloride of lime, for instance with only acetone or alcohol
yields chloroform.
A practical application of the new process is as follows:-
1 kilogram of acetone and 0.5 kilograms of citral are dissolved in 15 kilograms

page_text: of alcohol, and 1 litre of freshly filtered clear concentrated solution of chloride
of lime is added, the mixture being continually stirred; the mass becomes beated,
and is left to stand for several days, or the heating may be increased by boiling it
in a reflux cooling apparatus and so maintained for about six hours. When the
liquid has cooled, it is diluted with about 10 litres of water the oil that collects
on the surface is skimmed off and small quantities of superfluous acetone and
citral which did not take part in the reaction are removed from this oil by a
weak jet of steam, the oil is then boiled with litres of diluted solution of
chloride of iron of about 1.025 sp. gr. for at least one day. By the action
of the solution f chloride of iron not only is the substance altered into essence of
violets but also, simultaneously with this undesirablo odours are removed. The
oil obtained in such manner, and separated from the solution of chloride of
iron, is at first freed by a strong jet of steam from the small admixture of other
oils and then distilled again, with steam, and this fractional distillation repeated
if necessary. The volatile oil or essence obtained in such manner does not easily
evaporate, is of yellowish colour and has a scent similar to that of sandal wood
or fine cedar wood, and if suitably diluted it has a marked smell of freshly
gathered violets.
Instead of citral a double quantity of Indian Verbena-oil (Lemon grass) may
be used, in the present example therefore 1 kilogram. The process remains the
same. Instead of a saturated solution of chloride of lime 025 kilogram of
barium peroxide may be used, the other proportions remaining as described, said
barium peroxide being suspended in 0.5 kilogram water and added to the solution
of citral and of acetone in alcohol. Then the solution is heated and the process
conducted as described.
Dated this 21st day of November 1896.
BOULT & WADE,
Agents for the Applicant.
A New or Improved Process for the Manufacture of Artificial Essence
or Essential Oil of Violets.
A communication from FRANZ FRITZSCHE AND COMPANY of Hamburg-Uhlenhorst,
in the Empire of Germany.
I, ALFRED JULIUS BOULT
Chartered Pateut Agent, do
of 111, Hatton Garden, in the County of Middlesex,
hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement:-
This invention relates to a process for manufacturing hitherto unknown oils
having a violet scent.
Patents No. 8736 of May 1 1893 and No. 17539 of 18 September 1893 describe
the manufacture of ionone which is an essential oil, boiling at 128° under 12mm.
pressure, and of sp. gr. of 0.935. This oil is optically inactive.
The final product of the process according to the present invention is an oil
boiling at 142-150° C. under 12mm. pressure and of sp. gr. of from 0.94 to 0.95.
It differs from ionone by having when concentrated a very strong scent similar
to that of sandalwood by producing a left handed rotation of a polarised ray and
hy having when diluted a scent more closely approaching that of natural violets
than does that of ionone.
Analysis shows that this oil consists of several ketones of the group CHO

page_text: of higher boiling points and greater density than those of ionone. These ketones
are optically active and both their existence and their artificial production have
been hitherto unknown.
The process employed in carrying out this invention is as follows. A mixture
of 1 to 1 parts acetone (45 kg.) 1 part of lemon grass oil (38 kg.) 14 to 2 parts
alcohol (75 kg.) 1-2 parts of a concentrated lime-free solution of chloride of
lime (75 kg.) to which is added a little of cobaltous nitrate (30 gr.) dissolved in
water is boiled during 6-18 hours at a temperature of 70 80° C. in a reflux
cooling apparatus.
The alcohol and the excess of acetone are first distilled off and then an essential
oil is obtained, which, after the first distilled portion (about 4 kg.) of sp. gr. 0.88
has been removed represents the stuff for producing artificial oil of violets. It
is an essential oil with a boiling point of 155 to 175° at 12 mm pressure
(about 25 kg.).
This oil is heated at 110° C. with a solution of bisulphate of sodium of 11°
Beaume (42 kg. for 360 litres of water) in a vessel with a mixing device until
the samples distilled every day show that the first running which has an un-
pleasant smell has reached the density of 0.936. This happens after about 8 days
(the first running being about 8 kg.).
The crude product (about 17 kg.) in the vessel is then purified by fractional
distillation all the bad smelling parts being removed, so that finally there remains
an oil of a destiny of 0.948-0.952 (15° C.) boiling at 142-150° C. under 12 mm.
pressure.
The lightest portion of this oil has a sp. gr. of 0.945 and boils at 142° C.
under 12 mm. pressure, the largest portion of it which has the pleasantest and
strongest smell boils at 149° C. and has a sp. gr. of 0.953. Analysis has shown
that both substances belong to the group of Ketones C₁₂H₂O.
By using other Ketones instead of Acetone homologous substances may be
obtained.
The product obtained by the above described process contains no ionone for it
contains no ingredient boiling at 128° C. under the pressure of 12 mm. and having
a sp. gr. of 0.935. The violet like smell of the product obtained according to
the present invention is the result of the presence of substances which are different
from iouone as their sp. gr. and their boiling point are higher than those of ionone
the new product has the advantage that it can be manufactured in a very simple
and economical manner and as its smell is much more like that of real violets
than is the smell of iouone and as it is more constant and less volatile than ionone
it is much more suitable for artificial violet scent than the "ionone" which has
hitherto been the only artificially made substance known for this purpose and
which is much more difficult to manufacture.
Having now particularly described and ascertained the nature of the said in-
vention as communicated to me by my foreign correspondents and in what manner
he same is to be performed I wish it to be understood that I do not claim any-
thing described and claimed in the Specifications of Letters Patent Nos. 8736
and 17539 A.D 1893 granted to Johann Carl Wilhelm Ferdinand Tiemann, but
I declare that what I claim is :-
1. As an article of manufacture au essential oil having the smell of violets
boiling at 142° to 150° C. under a pressure of 12 mm. and of a specific gravity
of 0.948 to 0.952 (15° C.).
2. A process for the manufacture of hitherto unknown oils having the smell
of violets, which oils have a higher boiling point and higher specific gravity
than ionone.
3. A process for the manufacture of hitherto unknown oils boiling at 155--175° C.
under the pressure of 12 mm. which can be converted into violet-smelling oils of
higher specific gravity and higher boiling point than those of ionone by being
boiled with different substances such for instance as bisulphate of sodium.

page_text: 4. The manufacture of homologous substances by using other Ketones instead
of acetone.
5. A process for the manufacture of artificial essence of violets consisting in
causing lemongrass oil, alcohol, acetone, and concentrated solutions of salts of
hypochlorous acid to react on one another at the boiling temperature.
6. Process for manufacture of artificial essence of violets consisting in causing
lemongrass oil, alcohol, acetone, and concentrated solutions of salts of hypo-
chlorous acid to react on one another at a boiling temperature cobaltous nitrate
being added if desired.
BOULT & WADE,
Agents for the Applicant.
BOULT & WADE,
Agents for the Applicant.