Manufacture of Geraniol from Citronella-oil.
Year: 1893

page_text: Date of Application, 10th July, 1893
Complete Specification Left, 9th Apr., 1894-Accepted, 19th May, 1894
PROVISIONAL SPECIFICATION.
Manufacture of Geraniol from Citronella-oil.
I, JULIUS BERTRAM, Doctor of Philosophy, of 2 Brühl, Leipzig, in the
Kingdom of Saxony, do hereby declare the nature of this invention to be
follows:-
The constitution of citronella-oil is not yet fully investigated.
as
According to Gladstone (Jahresber. f. Chemie 1872, 811) and according to
Wright (Jahresber. f. Chemie 1875, 852) its principal component is citronellol
(CHO) which according to Gladstone boils at 200° C., and according to Wright
at 210 simultaneously with its decomposition.
Kremers (Exam. of the oil of Androp. Nardus (citronella oil) Cincinnati 1887)
found in the citronella oil a terpene, which boils between 160 and 170°, an
aldehyde (C,H,,O), and a alcohol (CHO), which is isomeric with the citronellol
and boils beween 217° and 222°; (centigrade) also acetic acid and valeric acid,
which probably occur in the shape of esters.
Schimmel & Co. (Handelsbericht 1888 April and October) found, that the
aldehyde discovered by Kremers is identical with the citronellon discovered by
them in various eucalyptus oils.
According to Dodge, (Amer. Chem. Journ. 1889, 466) the citronella oil contains
an aldehyde CHO "citronell-aldehyde" boiling between 202° and 207°, and an
alcohol which boils between 224° and 226° and whose constitution is said to be
expressed by the formula C10H2O. In addition to these components, the body
contains also a terpene, C₁,H16, probably, limonene.
My recent investigations of citronella-oil have shown, that it contains several
terpenes, pinene, camphene, and dipentene, as well as the aldehyde CHIBO
mentioned above, (citronellon or citronell-aldehyde)..
The alcoholic constituents include a substance, which boils between 230 and 235°
(centigrade) and occurs in very considerable quantities; it was found to be identical
with geraniol, the aromatic constituent of palmarosa oil and of geranium oil.
This is accompanied by small quantities of fatty acid esters of geraniol and
sesquiterpene.
The recovery of the geraniol in a pure state by means of fractional distillation,
is not immediately practicable, because neither the citronellon nor
the esters can be removed in this manner.
even in
часио,
The following methods may, however, be employed for obtaining the geraniol
from the citronella-oil.
1. The citronella oil is shaken with a sufficient quantity of a solution of sodium-
bisulphite, or of potassium-bisulphite, the crystalline bisulphite solution of
citronellon thus formed is subsequently separated from the oil mixture by pressure,
and the latter heated with an alcoholic solution of potash. After that, the
geraniol may be separated from its admixtures by fractional distillation with steam
or in vacuo.
2. If no value is attributed to the recovery of the citronellon, the citronella oil
may be directly saponified with alcoholic potash; thereby transforming most of
the citronellon into polymeric products which have a high boiling point and may
be separated from the geraniol by fractional distillation.

page_text: EXAMPLES.
1. 100 kilos. of citronella-oil are shaken with 20 to 40 kilos. of concentrated'
sodium bi-sulphite solution. After cooling, the oil is removed from the separated
bisulphite solution by pressure or suction, and heated with a solution of 6 kilos. of
potassium hydrate in 25 kilos. of alcohol, to the boiling point. Subsequently,
the alcohol is distilled off, and the oil driven into a receiver by admitting steam.
Finally the geraniol is purified by fractional distillation in vacuo, or with steam.
2. 100 kilos. of citronella-oil are heated with a solution of 10 to 15 kilos. of
potassium hydrate in 50 to 70 kilos. of alcohol, for about three hours, the alcohol
is distilled off and the residue treated as indicated in the first example.
If a closed retort be used, it is sufficient, to heat to 120° C. for an hour.
Instead of alcoholic potash, potassium alcoholate or sodium alcoholate or a
concentrated aqueous solution of potash 2 KOH + 1 H₂O may be employed.
The geraniol boils between 232 and 234 degrees C. It has a specific gravity
of 0-884 and is used in perfumery.
Dated this 10th day of July 1893.
FAIRFAX & WETTER,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Manufacture of Geraniol from Citronella-oil.
I, JULIUS BERTRAM, Doctor of Philosophy, of 2 Brühl, Leipzig, in the
Kingdom of Saxony, 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 :-
The constitution of citronella-oil has not hitherto been fully investigated.
According to Gladstone (Jahresber. f. Chemie 1872 811) and according to
Wright (Jahresber. f. Chemie 1875, 852) its principal component is citronellol
(CHO) which according to Gladstone boils at 200° C., and according to Wright
at 210° simultaneously with its decomposition.
Kremers (Exam. of the oil of Androp. Nardus (citronella oil) Cincinnati 1887)
found in the citronella oil a terpene which boils between 160 and 170°, an aldehyde
(CHO), and an alcohol, citronellol (C10H10), which is isomeric with the borneol
and boils between 217° and 222° (centigrade), also acetic acid and valeric acid,
which probably occur in the shape of esters.
18
Schimmel & Co. (Handelsbericht 1888 April and October) found, that the
aldehyde discovered by Kremers is identical with the citronellon discovered by them
in various eucalyptus oils.
According to Dodge, (Amer. Chem. Journ. 1889, 466) the citronella oil contains
an aldehyde CHO "citronell-aldehyde " boiling between 202° and 207°, and
an alcohol which boils between 224° and 226° and whose constitution is said to be
expressed by the formula C1,H2O. In addition to these components, the body
contains also a terpene, CH₁, probably limonene.
10
My recent investigations of citronella oil have shown, that it contains several
terpenes, pinene, camphene, and dipentene, as well as the aldehyde C10H180
mentioned above, (citronellon or citronell-aldehyde).
The alcoholic constituents include a substance which boils between 230 and 235°
(centigrade) and occurs in very considerable quantities; it was found to be
identical with geraniol, the aromatic constituent of palmarosa oil and of geranium
oil. This is accompanied by small quantities of fatty acid esters of geraniol and
sesquiterpene.
The recovery of the geraniol in a pure state by means of fractional distillation,

page_text: even in vacuo, is not immediately practicable, because neither the citronellon nor the-
esters can be removed in this manner.
The following methods may, however, be employed for obtaining the geraniol
from the citronella-oil.
1. The citronella-oil is shaken with a sufficient quantity of a solution of sodium-
bisulphite, or of potassium-bisulphite, the crystalline bisulphite compound of
citronellon thus formed is subsequently separated from the oil mixture by pressure,.
and the latter heated with an alcoholic solution of potash. After that, the geraniol
may be separated from its admixtures by fractional distillation with steam or
in vacuo.
2. If no value is attributed to the recovery of the citronellon, the citronella-oil may
be directly saponified with alcoholic potash; thereby transforming most of the
citronellon into polymeric products which have a high boiling point and may be
separated from the geraniol by fractional distillation.
3. The geraniol obtained as described above may also be purified by preparing
the crystalline compounds which are formed by combination of geraniol with
certain salts, such as the chloride or the nitrate of calcium or of magnesium.
(Jacobsen Lieb. Ann. d. Chem. Pharm.) and decomposing these compounds
with water.
The same process may also be performed on the fractions of citronella-oil which
boil from 220-235°, without previous purification of the oil with bisulphite of
sodium and alcoholic potash.
EXAMPLES.
1. 100 kilos. of citronella-oil are shaken with 20 to 40 kilos. of, concentrated
sodium bi-sulphite solution. After cooling, the oil is removed from the separated
bisulphite compound by pressure or suction, and heated with a solution of 6 kilos..
of potassium hydrate in 25 kilos. of alcohol, to the boiling point. Subsequently,
the alcohol is distilled off, and the oil driven into a receiver by admitting steam..
Finally the geraniol is purified by fractional distillation in vacuo or with steam.
2. 100 kilos. of citronella-oil are heated with a solution of 10 to 15 kilos. of
potassium hydrate in 50 to 70 kilos. of alcohol, for about three hours, the alcohol
is distilled off and the residue treated as indicated in the first example.
3. Equal parts of powdered calcium chloride and of crude geraniol from
citronella oil are mixed; there results a solid mass which is separated from the
oily admixtures by means of pressure, suction or centrifugal action and then
purified by washing with ether, petroleum-ether, chloroform, or other chemically
inert liquids.
The remaining solid mass, a mixture of calcium chloride and of a compound of
geraniol with that salt, is treated with water, and the regenerated geraniol is
separated from the adhering traces of ether etc. by fractional distillation with
steam or in vacuo.
If a closed retort be used, it is sufficient, to heat to 120° C. for an hour.
Instead of alcoholic potash, potassium alcoholate or sodium alcoholate or a
concentrated aqueous solution of potash 2 KOH+1 H₂O may be employed.
The geraniol boils between 230 and 232 degrees C., it has a specific gravity
of 0.884 and is used in perfumery.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is ;-
1. The manufacture of geraniol from citronella-oil by treating the said oil with a
solution of sodium- or potassium-bisulphite, and subsequently with an alcoholic
potash-solution, or by directly saponifying the same with alcoholic potash- or
soda-solution (sodium alcoholate or concentrated aqueous potash solution), and
subjecting the product of the reaction to fractional distillation, substantially as
described.

page_text: 2. The preparation of geraniol by treatment of the fractions of citronella-oil,
boiling from 220-235°, or of crude geraniol obtained in the manner described
above, with chloride or nitrate of calcium or of magnesium, and decomposition of
the resulting solid compounds with water, substantially as described.
Dated this 7th day of April 1894.
FAIRFAX & WETTER,
433, Strand, London, Agents.