Improvements in and connected with the Purification of Raw Spirit in order to Produce Highly Rectified Spirits of Wine, and Apparatus therefor.
Year: 1889

page_text: Date of Application, 2nd Apr., 1889
Complete Specification Left, 1st Jan., 1890-Accepted, 1st Feb., 1890
PROVISIONAI: SPECIFICATION.
Improvements in and connected with the Purification of Raw Spirit
in order to Produce Highly Rectified Spirits of Wine, and
Apparatus therefor.
I, CONRAD SCHMITT, of Wiesbaden, in the Empire of Germany, Analytical Chemist,
do hereby declare the nature of this invention to be as follows:-
This invention relates to a process and apparatus for producing bighly rectified'
ethylic alcohol from raw spirit and freeing the same from the bye-products formed.
during fermentation whereby the distilling operation is rendered unnecessary.
My improved process consists in purifying the raw spirit or freeing it from fusel
oil and other impurities by saturating the raw spirit with a solution of carbonate of
potassium and then treating the mixture with petroleum ether.
The petroleum ether containing the bye-products or impurities extracted from the
spirit is then treated in water of different temperatures and afterwards in spirits of
wine in such a manner as to extract the fusel oil and aromatic substances from the
petroleum ether.
The spirit so purified can be brought to a higher strength by treating it with such
a quantity of potash as to form two layers, the upper of which is a spirit of a high
strength containing only a small quantity of potash and the lower one a cold saturated
solution of potash containing only a small quantity of alcohol.
The cold saturated potash solution which forms the lower layer can be freed from
the small quantity of alcohol by mixing it with petroleum ether. The latter is capable
of dissolving the alcohol in order to extract it from the solution of potash, after which
the petroleum ether, containing the alcohol extracted from the said potash solution,
can be freed from the alcohol by treating it with water.
The spirit so treated with potash forming the upper layer and containing a small
quantity of potash can be freed from the latter by treating it with sulphuric acid for
the purpose of converting the potash dissolved in the alcoholic layer into sulphate of
potassium.
I recover the ethylic alcohol contained in the saturated solution of potash by treating
it with petroleum ether and then purifying the latter by means of water.
The apparatus which I find it advantageous to employ for carrying out my process
comprises a vessel in which I place the diluted raw spirit together with a quantity of
solution of potash just sufficient to avoid the formation of layers and with petroleum
ether, suitable means, such as a screw, being provided in the said vessel for effecting
a thorough mixture of the contents.
In the said vessel, after the two liquids have been thoroughly mixed and the
petroleum ether has become saturated with fusel oil the contents are left to settle when
the petroleum ether will form into a separate layer from the other liquid consisting of
spirits and potash.
A cock is provided in the said vessel through which the upper layer of liquid,
videlicet, the petroleum ether is then allowed to run off into and through a series of
connected U shaped tubes in order to effect the purification of the petroleum ether.
One portion of each of the said tubes is of smaller diameter than the other portion and
the former open into the latter underneath perforated plates for the purpose of
spreading the petroleum ether at the entrance of the larger parts of the tubes. Or
any other suitable arrangement can he employed for this purpose.
The impurities from the raw spirit retained and carried off by the petroleum ether
consist of fusel oil with a small quantity of ethylic alcohol and aromatic substances
which are of a certain commercial value and which have been invariably destroyed

page_text: and lost during the process hitherto employed for purifying the petroleum ether by
means of concentrated sulphuric acid.
In order to separate these valuable aromatic substances from the other impurities in
the petroleum ether and to purify the latter for re-use I place cold water in the larger
portion of the first tube which absorbs from the fine sprays of petroleum ether all the
ethylic alcohol but allows the petroleum ether which still retains the fusel oil to pass
through it.
The petroleum ether now only retaining the fusel oil and the aromatic substances
enters the larger portion of the next tube in which I place water at a temperature of
from 50° to 60° Celsius which absorbs all the fusel oil.
The petroleum ether now only containing the aromatic substances is then allowed to
enter the larger portion of the end tube in which is placed spirits of wine of 50 to
60 per cent. in volume and finally after passing in a fine spray through the diluted
alcohol which retains all the aromatic substances it enters a vessel in a completely
purified condition.
The purified petroleum ether is then pumped from this vessel back to the first
named vessel to serve for a fresh operation.
Dated the 2nd day of Anril 1800
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in and connected with the Purification of Raw Spirit
in order to Produce Highly Rectified Spirits of Wine and
Apparatus therefor.
I, CONRAD SCHMITT, of Wiesbaden, in the Empire of Germany, Analytical
Chemist, do hereby declare the nature of the said invention and in what manner the
same is to be performed to be particularly described and ascertained in and by
the following statement :-
This invention relates to a process and apparatus for producing highly rectified
ethylic alcohol from raw spirit and freeing the same from the bye-products formed
during fermentation whereby the distilling operation is rendered unnecessary.
For the purpose of my invention I utilize the property possessed by petroleum
ether for freeing raw spirit from fusel oil for which purpose the spirit must be of
about 50% alcoholic strength.
I have found by experiment that petroleum ether or petroleum even in the
presence of a salt has a very limited purifying power and will only extract small
quantities of fusel oil from alcohol containing a large percentage of the said oil.
The power which 50% proof spirits of wine has for retaining fusel oil is sufficient
to counteract that of the petroleum or petroleum ether and to keep a quantity of
from 0.2 to 0.3 per cent. in volume of fusel oil constantly dissolved which prevents
the petroleum ether from removing even the smallest quantity of fusel oil from the
spirits of wine.
I have also found that the quantity of fusel oil which is retained by the spirits of
wine and therefore not given up to the petroleum or petroleum ether depends on the
amount of alcohol contained in the spirit and that spirits of wine having only 30%
in volume of alcohol are unable to yield its impurities to the petroleum ether when
the fusel oil does not exceed 0.2%.
These experiments together with the hereinafter mentioned and proved facts
regarding the action of potash on spirits of wine have led me to the belief that
petroleum or petroleum ether could be used more effectually as a means for freeing
spirits from fusel oil if only it could be made possible, through the use of proper
means, such for instance as potash, to reduce the power of the ethylic alcohol to
dissolve fusel oil to a minimum.
I then found by experiment that if a cold saturated solution of carbonate of
potassium be mixed with spirits of wine of 94% in volume instead of a partial

page_text: mixture of the two liquids taking place as might be expected and as would actually
be the case with all other cold saturated solutions of salts (whereby part of the water
is absorbed by the alcohol) and a corresponding quantity of the salt not remaining
dissolved in the layer of alcohol becoming crystallized practically no appreciable
mixture of the layers takes place.
The water absorbing power of potash is superior to that of any other salt and
still more so than that of ethylic alcohol. Both liquids can apparently be placed
together without their becoming mixed and the specific gravity of the two layers
becomes equal.
When a cold saturated solution of potash is mixed with an equal volume of spirits
of wine of less strength, the balance is soon formed through the solution of potash
absorbing a certain quantity of water according to the degree of concentration of
the alcoholic liquid after which the layer of alcoholic solution in consequence of
being then more concentrated can dissolve a quantity of carbonate of potassium
according to the water it contains and on the other hand the solution of potash is
enabled to retain a quantity of alcohol in solution according to the water it contains.
By adding salt to the solution, the specific gravity of the carbonate of potassium will
be raised and as the concentration of the solution is increased a quantity of water
according to the freshly absorbed potash will leave the alcoholic solution and
directly the solution of potash becomes saturated the alcoholic layer will be of a
strength of about 94% in volume.
If the spirits of wine used contains any of the bye-products formed during_
fermentation these impurities will remain in the rectified spirits of wine.
By the addition of as much saturated solution of carbonate of potassium as it will
absorb to such spirits of wine of about 30% volume of alcohol containing fusel oil
without causing a separation of the two liquid layers the natural capacity of the
alcohol for retaining the fusel oil will be destroyed. In this case a liquid, which itself
is insoluble in spirits of wine and possesses the property of freeing the same from.
fusel oil and at the same time has but little effect on the alcohol, will evince a tendency
to absorb when well mixed with the impure alcoholic solution of potash, the fusel oil
which is now only lightly held in solution.
Experiments have fully proved the truth of the above assertion.
The quantity of carbonate of potassium which can be dissolved in a given quantity
of a mixture of water and ethylic alcohol without risk of forming layers depends on
the temperature and on the strength of the alcohol. A solution of 30% volume of
spirits of wine can at a temperature of about 18° Celsius absorb 380 cubic centimeters
of a solution of potash of a specific gravity of 1.500 without forming layers. A larger
quantity of solution of potash or a higher temperature would necessarily cause the
formation of layers.
Petroleum ether is an inert chemical body and although it cannot be regarded as an
excellent means for freeing spirit from fusel oil it has but very little absorbing influence
on the alcohol in low proof spirits of wine; I have therefore chosen it for the purpose
of my invention.
I take petroleum ether of commerce and treat the same with concentrated sulphuric
acid.
From the petroleum ether thus treated I separate about 50 per cent. by distillation
so as to obtain a portion which will boil at a low temperature and which I will here-
after refer to as portion No. I. The remaining portion will be referred to as No. II.
My experiments, the results of which for facility of comprehension I have set out
in the annexed table, I performed in the following manner; a certain quantity of
petroleum ether was vigorously shaken up with a certain quantity of spirits of wine
of a known degree of alcoholic strength and containing a known percentage of fusel
oil together with the necessary quantity of potash in the form of a solution of 1-5
specific gravity, the whole was then placed into a covered separating funnel thus
allowing the petroleum ether to absorb fusel oil. After the separating process was
completed the quantity of fusel oil remaining in the solution of spirits of wine was
ascertained by Röse's method.

page_text: Volume Volume
Portion in cubic in cubic
Volume
in cubic
Con- Strength
secu-
tive
num-
centi-
of
centi-
centi-
Per-
Per
centage
Per-
of alcohol centage
prepared meters.
meters of
meters
solution
of fusel centage
in
volume. fusel oil.
of
petro-
of spirits
of
oil after of fusel
leum
of wine to
of potash
petro-
bers.
ether
be freed
leum
used (of
the oil ex-
1-5
shaking tracted.
used. from fusel
ether
1
specific operation.
It will be clear from the above table that the power of the low proof spirit to retain
fusel oil can, by the addition of proportionate quantities of potash, be reduced to such
an extent as to allow, by employing sufficient quantities of petroleum ether
(particularly if of low boiling point) of effecting the complete purification from
fusel oil at one operation and without having recourse to distillation (see experiment
No. 5).
From the above described experiments it follows that it is possible by a proper use
of a solution of potash sufficient to avoid the formation of layers with the addition of
petroleum or petroleum ether, to free raw spirits from fusel oil and afterwards by
proper treatment with a solution of potash to cause the formation of layers and at the
same time concentrate the spirits of wine to about 94%, thus obtaining highly
rectified spirits of wine from raw spirit without distillation.
I will now describe my invention by reference to the accompanying drawing which
represents a longitudinal section of the apparatus I find it advantageous to employ for
carrying the same into practice.
I place the diluted raw spirit with a quantity of solution of potash just sufficient to
avoid the formation of layers, together with petroleum or petroleum ether in a vessel B
and then thoroughly mix the same by suitable means, such for example as the screw F
shown in the drawing.
After the two liquids have been thoroughly mixed and the petroleum or petroleum
ether has become saturated with fusel oil the contents are left to settle till the
petroleum or petroleum ether forms a separate layer from the other liquid consisting of
spirits and potash. The cock K is then opened and the upper layer of liquid, that
is to say, the petroleum ether is allowed to run off through the opening G into and
through a series of connected U-shaped tubes in order to effect the purification of the
petroleum or petroleum ether. A portion of each of the said tubes is of relatively small
diameter as shewn at b, a, a, and the other portion is of larger diameter as shewn at P,
P¹, P, P. The smaller parts 6 and a, a of the tubes open into the larger portions
underneath perforated plates s placed inside the latter for the purpose of spreading the
petroleum ether at the entrance of the larger parts of the tubes or any other suitable
arrangement can be employed for this purpose.
The impurities from the raw spirit retained by the petroleum or petroleum ether
consist of fusel oil with a small quantity of ethylic alcohol and aromatic substances

page_text: which are of a certain commercial value and which have been invariably destroyed
and lost during the process hitherto employed for purifying the petroleum or petroleum
ether by means of concentrated sulphuric acid.
In order to separate these valuable aromatic substances from the other impurities
in the petroleum or petroleum ether and to purify the latter for re-use, 1 proceed as
follows:-
The petroleum or petroleum ether after leaving the vessel B charged with fusel oil,
ethylic alcohol and aromatic substances is caused to pass through the first portion b.
of the tubes and through the perforated plate s in a finely divided spray into the
larger portion P of the first tube which is half filled with cold water. The cold water
absorbs from the fine sprays of petroleum or petroleum ether all the ethylic alcohol
which is very soluble in cold water but allows the petroleum or petroleum ether which
still retains the fusel oil, which is practically insoluble in water to pass through it.
It has been found by experiment that an equal volume of water when shaken up.
with petroleum or petroleum ether containing 0.3% of fusel oil does not absorb more
than 006% of the fusel oil.
The petroleum or petroleum ether now only retaining the fusel oil and the aromatic
substances enters the larger portion P¹ of the next tube which is also half filled with
water at a temperature of from 50° to 60° Celsius in which all the fusel oil is absorbed,
it having been proved experimentally that when petroleum ether containing 0.3% of
fusel oil is shaken up in an equal volume of water of a temperature of from 50° to 60°
Celsius the whole of the fusel oil is readily abstracted.
If by means of a single tube a P₁ half filled with warm water as described the
petroleum or petroleum ether has not been sufficiently freed from fusel oil, the
petroleum ether may successively pass through two or more similar tubes a, P¹ in the
same manner as described for the first tube a, P¹.
The petroleum or petroleum ether, containing now only the aromatic substances
which are neither soluble in cold water nor in warm water, is then allowed to enter the
larger portion P of the end tube which is half filled with spirits of wine of from 50%
to 60% in volume and finally after passing in a fine spray through the diluted alcohol
which retains all the aromatic substances it enters the vessel R in a completely
purified condition.
v, v are inlet tubes for the introduction of the necessary liquids for purifying the -
petroleum or petroleum ether, into the portions P, P1, P₁ of the tubes.
n,-n, are outlet cocks for emptying the larger portions of the tubes.
The purified petroleum or petroleum ether is pumped from the vessel R back through
the tube Z into the vessel B to serve for a fresh operation.
The vessel B is provided with an outlet cock H at its lower end and with an
opening and cover L at the upper end for cleaning purposes and the vessel R is
provided with a similar opening and cover L'.
The spirit freed from all of the petroleum or petroleum ether and fusel oil and which
contains from the process a certain quantity of carbonate of potassium is then saturated
with potash in suitable vessels in order to form layers as before described.
After complete separation, the cold saturated solution of potash which only retains
a very small quantity of spirit (say about 0·3%) is then separated by suitable means
from the clear upper layer which consists of ethylic alcohol of about 94% in volume
and 6% in volume of water and is then concentrated, by evaporation for example, to
render it suitable for re-use.
The cold saturated potash solution thereby obtained, which forms the underneath
layer, can be freed from the small quantity of alcohol referred to by mixing it with
petroleum or petroleum ether. The latter is capable of dissolving the alcohol and of
extracting it from the solution of potash, after which the petroleum or petroleum ether
containing the alcohol extracted from the said cold saturated potash solution may be
separated from the latter in any suitable way and can be freed from the alcohol by
mixing it with water which dissolves the alcohol.
The rectified spirit forming the upper layer and still containing a small quantity
of carbonate of potassium can be freed therefrom by placing in the spirit a quantity of

page_text: sulphuric acid (either free or in combination with lime) equal to the quantity of
carbonate of potassium whereby sulphate of potassium is formed which being insoluble
in the 94% alcohol becomes separated therefrom. 100 litres of the rectified spirits of
wine will require about grammes of English sulphuric acid; this quantity may,
however be substituted by a corresponding or equivalent quantity of sulphuric acid
combined with lime (gypsum); an excess of the latter may be allowed.
The alcohol can be afterwards filtered or decanted in order to separate the flakes of
sulphate of potassium (and carbonate of lime and possibly sulphate of lime if the
sulphuric acid be used in combination with lime) and is then not in any way dis-
tinguishable from the finest spirit produced by the ordinary methods.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, 1 declare that what I
claim is
1. The herein described process for purifying spirit or freeing it from fusel oil by
nearly saturating the spirit with a solution of carbonate of potassium, and then treating
it with petroleum or petroleum ether.
2. The berein described process of purifying petroleum or petroleum ether con-
taining the bye-products extracted from the spirit and for extracting the aromatic
substances as well as the fusel oil by first treating the petroleum or petroleum ether
in water of different temperatures and afterwards in spirits of wine.
3. The herein described process for producing highly rectified spirits of wine and
freeing the same from salts and other impurities by treating it with a saturated solution
of potash, and then with sulphuric acid (either free or in combination with lime) for
the purpose of converting the potash dissolved in the alcoholic layer into sulphate of
potassium.
4. The apparatus for purifying raw spirit comprising a mixing vessel for freeing
the spirit from fusel oil and a series of tubes containing water and spirit through
which the petroleum or petroleum ether is conducted in the manner and substantially
as hereinbefore described.
5. The herein described process for recovering the ethylic alcohol contained in the
saturated solution of potash used in the process characterised in claim 3 by treating
it with petroleum or petroleum ether and then purifying the latter by means of water.
Dated the 1st day of January 1890.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.