Improvements in the Manufacture of Iso-eugenol and Poly-iso-eugenol.
Year: 1891

page_text: Date of Application, 4th June, 1891
Complete Specification Left, 19th Feb., 1892-Accepted, 26th Mar., 1892
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Iso-eugenol and
Poly-iso-eugenol.
I, JAMES YATE JOHNSON, of 47 Lincoln's Inn Fields, in the County of
Middlesex, Gentleman, do hereby declare the nature of this invention (which
has been communicated to me from abroad by Dr. F. Von Heyden Nachfolger
of Radebeul, near Dresden, in the Empire of Germany) to be asfollows :-
In the manufature of iso-eugenol according to this invention an alkaline com-
pound of eugenol is heated either alone or in the presence of an indifferent or
neutral solvent such as water, alcohol or hydro carbon or in the presence of an
excess of a methyl alcoholic, ethyl alcoholic or aqueous alkaline lye. The inven-
tion further relates to the purification of iso-eugenol and to the production of poly-
iso-eugenol as hereinafter described.
According to Eykmann (Berichte der deutschen Chemischen Gesellschaft 23-857)
and Ciamician and Silber (Berichte der deutschen Chemischen Gesellschaft 23-1160)
sassafras oil is converted into iso-sassafras oil by heating with potash lye on a water
bath.
The proportions to be employed for this reaction are alcohol 500 cubic centi-
metres, potash 250 grammes and sassafras oil 100 grammes.
Eugenol when subjected to the same treatment remains almost unchanged:
attempts have been made to convert eugenol into an isomer by means of alcoholic
potash but the results have not been satisfactory.
It has been found that under the conditions under which sassafras oil is converted
into iso-sassafras oil that is to say by heating 100 grammes of sassafras oil with 250
grammes of potash and 500 cubic centimetres of alcohol, eugenol remains almost.
unchanged even after heating for several days.
My foreign correspondents have now discovered that by heating eugenol to a
certain temperature as hereinafter explained with alcoholic. potash at ordinary
atmospheric pressure it can be readily converted into iso-eugenol without the
formation of resinous bye-products the quantity of potash being increased or that
of the alcohol diminished so as to obtain a suitably concentrated solution of potash.
Even when the quantity of potash is increased to 270 grammes of potash
to 100 grammes of eugenol and 500 cubic centimetres of alcohol the greater part of
the engenol becomes converted into iso-eugenol after heating for 24 hours on an oil
bath in a reflux cooler. It is advantageous to increase the quantity of potash
to 300 grammes and to reduce the quantity of alcohol to about 200 cubic centi-
metres. In practice the process may be conducted as follows for example.
Example I. From a solution of 1500 grammes of potash in 7½ litres of spirit and
500 grammes of eugenol about 6 litres are distilled off or evaporated. (The
residual liquid then usually separates into 2 layers) the lower layer being strongly
alkaline contains no eugenol and may be removed without materially influencing the
subsequent reaction.
reflux
The materials are now heated to boiling for about 10 hours preferably in
cooler. The boiling point of the reacting mass lies between about 105 and
125 degrees Centigrade according to the strength of the alcohol employed and the
quantity of alcohol evaporated. After heating for from 6 to 20 hours (usually
about 8 or 9 hours) the product of the reaction is mixed with water and the alcohol
subsequently distilled off. On acidulating the solution the crude iso-eugenol
separates which boils at between about 258 and 269 degrees Centigrade. The
boiling point of pure iso-eugenol is between 264 and 265 degrees Centigrade.

page_text: .
When soda is employed in place of potash the eugenol remains unchanged. On
the other hand mixtures of potash and soda may be employed with good effect.
Methyl alcohol may be employed in place of the ethyl-alcohol and mixtures of
alcohol and water or water alone may be employed in place of the alcohol.
Example II. 300 grammes of potash from 100 to 400 grammes of water and
100 grammes of eugenol are dissolved together and the resulting liquid consisting of
two layers is heated to boiling preferably in a reflux cooler (when a stronger
potash lye is employed the temperature required is somewhat lower). The boiling
point is between about 115 and 150 degrees Centigrade. After from about 6 to
30 hours (according to the degree of concentration of the potash lye) the lower
layer consisting of a solution of potash is removed the residue being dissolved in
water, and acidulated iso-eugenol separates out. It is by no means essential to
employ a solvent such as water and alcohol or so large an excess of potash as
described in Examples I and II as the potassium eugenol when heated changes
spontaneously into potassium iso-eugenol.
It is preferable to heat the potassium compound of eugenol not in an absolutely
dry condition but in the presence of some neutral liquid such as water alcohol or
hydro-carbon.
Example III. 300 grammes of potash are dissolved with from 150 to 300 grammes
of water and 100 grammes of eugenol the materials being well shaken together the
lower alkaline layer is separated and the upper layer consisting of potassium eugenol
and a certain quantity of water is heated either alone or with the addition of water,
alcohol, glycerine or xylol preferably in a reflux cooler to from 100 to 170 degrees
Centigrade or preferably to from 120 to 140 degrees. Centigrade. The subsequen
treatment is the same as hereinbefore described in Examples I and II.
The proportions given in Examples I to III may evidently be varied within wid
limits. The quantity of solvent employed may be diminished but may not be too
largely increased.
Iso-eugenol does not appear to have heretofore been obtained in a condition of
purity. Pure iso-eugenol resembles in its properties the nearly related anethol
being like the latter a crystallizing substance melting at about 33 degrees Centigrade,
and boiling at about 264 or 265 degrees Centigrade.
Pure iso-eugenol can be obtained from the crude iso-eugenol by two methods.
a. By freezing ont. The crude iso-eugenol which may be diluted with a solvent
is exposed to a very low temperature then subjected to crystallization by a grating
or grinding process or the introduction of crystals of iso-cugenol being afterwards
mechanically separated from the inother lye."
b. By conversion into the alkaline or earthy alkaline salts. These salts are
distinguished by their insolubility especially in the presence of an excess of a base
so that they may be employed for the purification of the iso-eugenol. Take for
example 100 grammes of sodium hydrate dissolved in from 1 to 3 litres of water
and add 400 grammes of crude iso-eugenol. The crystalline paste being pressed
the iso-eugenol is separated from the pressed cakes by means of an acid. The crude
potassium iso-eugenol obtained according to Examples 1 to 3 may be dissolved with
sufficient boiling water to produce on cooling a crystalline paste which is pressed
and decomposed with acid.
Iso-eugenol resembles anethol also in respect of its strong tendency to the
formation of condensation products. It changes into poly-iso-cugenol under treat-
ment with condensing agents such as gaseous or aqueous mineral acids, or with acid
chlorides and bromides, and metalloid chlorides and bromides, chlorides and
bromides of calcium, magnesiuin, aluminium, zinc, iron, and the like and in
particular with any substance capable of readily forming hydrochloric or hydro-
bromic acid such for example as organic acid chlorides or bromides. Traces of
the substances mentioned are sufficient to convert the iso-eugenol into poly-iso-
eugenol.
Poly-iso-eugenol may be produced very quickly and in considerable quantities by
conducting the process as next hereinafter described. Crude potassium iso-eugenol

page_text: obtained according to the processes hereinbefore described in Examples 1 to 3 is
decomposed by the addition of hydrochloric acid. The crude iso-eugenol separated
is heated to about 100 degrees Centigrade with a small residue of the acid mother
lye. The small quantity of hydrochloric acid present is sufficient for the conversion
or polymerising of the iso-eugenol the product which at first is thinly liquid sets
or hardens after a time into a crystalline cake of poly-iso-eugenol which can be
purified by recrystallization out of alcohol. It forms colourless, odourless and
tasteless needles melting at 177 degrees Centigrade.
<<
Dated this 4th day of June 1891.
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, Agents.
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Iso-eugenol and
Poly-iso-eugenol.
I, JAMES YATE JOHNSON of 47 Lincoln's Inn Fields in the County of
Middlesex Gentleman do hereby declare the nature of this invention (which has
been communicated to me from abroad by Dr. F. Von Heyden Nachfolger, of
Radebeul near Dresden in the Empire of Germany) and in what manner the same
is to be performed to be particularly described and ascertained in and by the
following statement :-
In the manufacture of iso-eugenol according to this invention an alkaline com-
pound of eugenol is heated, either alone or in the presence of a chemically inactive
or neutral diluent or solvent such as water, alcohol, or hydrocarbon or in the
presence of an excess of a methyl-alcoholic ethyl-alcoholic or aqueous-alkaline
Ive. The invention further relates to the purification of iso-cugenol and to the
production of poly-iso-eugenol as hereinafter described.
According to Eykman (Berichte der deutschen Chemischen Gesellschaft vol. 23
p. 857) and Ciamician and Silber (Berichte der deutschen Chemischen Gesellschaft
vol. 23 p. 1160) sassafras oil is converted into iso-sassafras oil by heating with
potash lye on a water bath. The proportions to be employed for this reaction are
alcohol 500 cubic centimetres, potash 250 grammes and sassafras oil 100 grammes.
Eugenol when subjected to the same treatment remains almost unchanged.
Ciamician and Silber have stated (see Berichte der deutschen Chemischen
iesellschaft vol. 23 p. 1164) that they endeavoured to convert eugenol into an
isomer by means of alcoholic potash but neither they nor Eykman were able to
obtain a complete conversion. After boiling for 24 hours on a water bath a
product was obtained which appeared to have no constant boiling point. The parts
having the higher boiling point boiled at from 252 to 253 degrees centigrade
whereas the original eugenol boiled at 247 degrees centigrade.
The boiling point of pure iso-eugenol is found to lic between 264 and
265 degrees centigrade and therefore Ciamician and Silber appear to have obtained
a mixture of eugenol with merely a small quantity of iso-eugenol.
Haarmann & Reimer have repeated this experiment with equal want of success
for they say (German Patent No. 57808) that in order to convert eugenol into
is-eugenol it is necessary to heat eugenol with a watery or alcoholic potash lye
under pressure and for several days to 130° centigrade. Under these conditions
resinous bye products are said to result whilst the eugenol on heating with amyl-
alcoholic potash is readily converted into iso-eugenol. The proportions given are
100 grammes of eugenol 250 grammes potash and 500 grammes or 625 cubic centi-
metres of amyl-alcohol this being a still larger proportion of the solvent than was
employed by Ciamician & Silber (500 cubic centimetres of ethyl-alcohol).
On repeating the experiments made by Ciamician & Silber it has been found
by my foreign correspondent that under the conditions under which sassafras oil is
converted into iso-sassafras oil that is to say by heating 100 grammes of sassafras

page_text: oil with 250 grammes of potash and 500 cubic centimetres of alcohol, eugenol
remains almost unchanged even after heating for several days.
My foreign correspondent has discovered that by heating eugenol with alcoholic
potash at ordinary atmospheric pressure but at a higher temperature than has been
hitherto employed and increasing the quantity of potash or diminishing the quantity
of the alcohol so as to obtain a sufficiently concentrated solution of potash cugenol
can be readily converted (usually in a few hours) into iso-eugenol without the
formation of resinous bye products. The necessary higher temperature can be
obtained by heating on an oil bath in place of a water bath. Even when the
quantity of potash is increased to 270 grammes of potash to 100 grammes of
eugenol and 500 cubic centimetres of alcohol the greater part of the eugenol
becomes.converted into iso-eugenol after heating for 24 hours on an oil bath in a
reflux cooler. It is advantageous to increase the quantity of potash to 300 grammes
and to reduce the quantity of alcohol to about 200 cubic centimetres. I give the
following examples of the manner in which the process may be conducted.
Example I. From a solution of 1500 grammes of potash in 7 litres of alcohol
and 500 grammes of eugenol about 6 litres are distilled off or evaporated. The
residual liquid then usually separates into two layers the lower layer is strongly
alkaline and contains no eugenol and may be removed without materially influencing
the subsequent reaction.
The materials (i.e. the upper layer with or without the lower layer) are now
heated to boiling for about 10 hours in a reflux cooler. The boiling point of the
reacting mass lies between about 105 and 125 degrees centigrade according to the
strength of the alcohol employed and the quantity of alcohol evaporated. After
heating for from 6 to 20 hours (usually about 8 or 9 hours) the product of the
reaction is mixed with water and the alcohol may be subsequently distilled off if
desired. On acidulating the solution the crude iso-eugenol separates which (with
the exception of a slight amount of first runnings or of supernatant waste and a
small residue) boils at between about 258 and 269 degrees centigrade. The boiling
point of pure iso-eugenol is between 264 and 265 degrees centigrade. When soda is
employed in place of potash the eugenol remains unchanged. On the other hand
mixtures of potash and soda may be employed with good effect for example_a
mixture of equal parts of potash and soda produces the same effect as pure potash.
The quantity of potash may be even further reduced.
Methyl-alcohol may be employed in place of the ethyl-alcohol and mixtures of
alcohol and water or water alone may be employed in place of the alcohol.
Example II. 300 grammes of potash from 100 to 400 grammes of water and
100 grammes of eugenol are dissolved together and the resulting liquid consisting
of two layers is heated to boiling preferably in a reflux cooler (when a stronger
potash lye is employed it is only necessary to licat to below but near boiling). The
boiling point is between about 115 and 150 degrees centigrade. After from about 6
to 30 hours (according to the degree of concentration of the potash lye) the lower
layer which consists of a solution of potash is drawn off or removed the residue or
upper layer being dissolved in water and acidulated iso-eugenol separates out.
It
is not essential to employ a solvent such as water and alcohol and so large an excess
of potash as is described in Examples I and II as the potassium eugenol when
heated changes spontaneously into potassium iso-eugenol.
In the description of Example I it has been stated that the potash solution in
excess forming the bottom layer may be removed before the heating without
materially affecting the reaction. It is preferable to heat the potassium compound
of eugenol not in an absolutely dry condition but in the presence of some neutral
liquid such as water alcohol or hydro-carbon.
A very simple process for the production of iso-eugenol is given in the following
example.
Example III. 300 grammes of potash are dissolved with from 150 to 300 grammes
of water and 100 grammes of eugenol the materials being well shaken together
the lower alkaline layer is separated and the upper layer consisting of potassium

page_text: eugenol and a certain quantity of water is heated either alone or with the addition
of water, alcohol, glycerine or xylol (preferably in a reflux cooler) to from 100 to
170 degrees centigrade or preferably to from 120 to 140 degrees centigrade.
The subsequent treatment is the same as hereinbefore described in Examples |
and II.
The proportions given in the foregoing examples may evidently be varied within
wide limits. The quantity of solvent employed may be diminished but it should
not be too largely increased as this would lead to unpracticable degrees of dilution
such as those employed by Ciamician and Silber for example.
Iso-eugenol does not appear to have heretofore been obtained in a condition of
purity. Pure iso-eugenol resembles in its properties the nearly related anethol
being like the latter a beautiful crystallizing substance readily melting at about.
33 degrees centigrade and boiling at about 264 or 265 degrees centigrade.
Tiemann & Haarmann & Reimer give from 258 to 262 degrees centigrade as the
boiling point of the liquid iso-eugenol which they have obtained.
Pure iso-engenol can be obtained from crude iso-eugenol by two methods.
a. By freezing out. The crude iso-eugenol which may be diluted with a solvent
is exposed to a very low temperature then subjected to a crystallization by stirring
or the introduction of crystals of iso-engenol in order to effect crystallization the
purified iso-eugenol being afterwards mechanically separated from the mother lye.
This may be done by suction centrifugal force or by pressure.
b. By conversion into the alkaline or earthy alkaline salts. These salts are
distinguished by their relative insolubility especially in the presence of an excess
of a base so that they may be employed for the purification of the iso-eugenol.
For example take 100 grammes of sodium hydrate dissolved in from 1 to 3 litres
of water and add 400 grammes of crude iso-eugenol. The crystalline paste being
pressed the iso-eugenol is separated from the pressed cakes by means of an acid.
The crude potassium iso-eugenol obtained according to Examples III and III
may be dissolved with sufficient boiling water to produce on cooling a crystalline
paste which is pressed and decomposed with acid.
Iso-eugenol also resembles anethol in its strong tendency to the formation of
condensation products. It changes into poly-isc-eugenol under treatment with
condensing agents such as gaseous or aqueous mineral acids, or with acid chlorides
and bromides, and metalloid chlorides and bromides, chlorides and bromides of
calcium, magnesium, aluminium, zinc, iron and the like and in particular with any
substance capable of readily forming hydrochloric or hydrobromic acid such for
example as organic acid chlorides or bromides. Traces of the substances mentioned
are sufficient to convert the iso-eugenol into poly-iso-eugenol.
Poly-iso-eugenol may be produced very quickly and in considerable quantities
by conducting the process as follows:
Crude potassium iso-eugenol obtained according to the processes hereinbefore
described under Examples I, II, III is decomposed by the addition of hydrochloric
acid. The crude iso-eugenol separated is heated to about 100 degrees centigrade
with a small residue of the acid mother lyc. The small quantity of hydrochloric
acid present is sufficient for the conversion or polymerising of the iso-eugenol the
product which at first is thinly liquid sets or hardens after a time into a crystalline
cake of poly-iso-eugenol which can be purified by recrystallization out of alcohol.
It forms colourless, odourless and tasteless needles melting at
177 degrees
centigrade.
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. The manufacture of iso-engenol by heating an alkaline compound of eugenol
either alone or in the presence of chemically inactive (indifferent) or neutral
diluents or solvents such as water alcohol hydro-carbon or in the presence of an
excess of a methyl alcoholic, ethyl alcoholic or watery alkaline lye.

page_text: 2. The production of pure iso-eugenol either by freezing out from crude iso-
eugenol or by means of the alkaline or earthy alkaline salts.
3. The production of poly-iso-eugenol by treating iso-eugenol with condensing
agents.
Dated this 19th day of February 1892
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, London, W.C., Agents.