Improvements in the Treatment of Commercial Alcohols.
Year: 1888

page_text: Date of Application, 28th Nov., 1888
Complete Specification Left, 22nd Aug., 1889-Accepted. 16th Nov., 1889
PROVISIONAL SPECIFICATION.
Improvements in the Treatment of Commercial Alcohols.
I, HUGUES ERNEST SOREL of 59 rue Bonaparte, Paris in the Republic of France,
Gentleman, do hereby declare the nature of this invention to be as follows:-
To purify crude alcohols obtained by a first continuous distillation a second
intermittent operation called rectification is employed, based in principle upon the
notable difference in volatility existing between the principal constituents of crude
alcohols.
In this operation the crude alcohol, mixed with more or less water, is brought
gradually to the boiling point, and the current of vapour thus obtained is submitted
to a progressive cooling, the condensed products being constantly carried back and
the vapours which have escaped this partial condensation alone being collected.
It will be understood that the addition of water having raised the boiling point of
the crude alcohol the more volatile bodies contained in the crude alcohol will first
predominate in the vapours produced, and consequently in the liquids collected.
After the progressive disappearance of these comes an alcohol less charged with
volatile bodies; but the boiling point rising bodies which are less volatile than
alcohol appear little by little and finally predominate, when their progressive_con-
densation has sufficiently charged the shelves of the column, for them to acquire a
notable vapour tension, and the temperature of these shelves has risen in consequence
of the etheric alcohol leaving them.
If, as is done at present, the condensation of the vapours which escape from the
apparatus, is effected by a sudden cooling, and if the condensed products coming
from the different phase of the rectification are separated in special receivers a series
of products is obtained succeeding each other in the following order :-
1. Dilute alcohol charged with very volatile principles (mainly aldehydes and
ethers).
2. Concentrated alcohol charged with a lesser proportion of all these products.
3. Alcohol practically (if not chemically) pure.
4. Concentrated alcohol, to some extent contaminated with less volatile principles.
5. Mere dilute alcohol saturated with less volatile principles.
6. Very weak alcohol (petites eaux) on which float less volatile principles but
slightly soluble in water (fusel oils).
After the separation of alcohol practically accepted as pure, the next thing is to
rectify the more impure alcohols which have been put aside; then an insurmountable
difficulty is encountered, namely: (1) that even the very volatile bodies do not
evaporate instantaneously but progressively together with their solvent, and con-
sequently contaminate a quantity of the product which becomes larger as the quantity
of volatile bodies existing in the liquid to be rectified increases. (2) That bodies less
volatile than ethylic alcohol, being concentrated with the residues of the first opera-
tions, soon acquire a vapour tension such that from the first they pass even into the
refrigerator so that it is very soon impossible to obtain even reasonable pure alcohol
by rectification.
Another difficulty is also often encountered a difficulty of another order the
ammoniacal salts and salts of organic bases existing in the greater part of crude
alcohols and even in refined alcohols are partially decomposable by heat and the bases
set at liberty react slowly upon the aldehydes still in solution to furnish nitrogenous
compounds, which are also slowly decomposable by hot water and consequently during
the entire rectification disengage aldehyde, which contaminates the condensed products,
and a part or the whole of the alcohol called "de cœur," the extraction of which is
the object of the rectification.

page_text: On the other hand the recombination of these volatile basic compounds and
aldehydes is, according to my personal experience, very slow and very difficult so
long as the bodies exist in the state of vapour; this admits of their separation by
means of the processes hereinafter described, consequently preventing the reformation
of these mixed compounds in the condensation products intended for re-rectification.
Many arrangements have in former times and recently been patented with the
object of utilising the difference which exists between the boiling points of the
impurities normally accompanying alcohol, to separate pure ethylic alcohol from these
impurities. Theory and practice are in perfect accord to shew that this basis of
operation is founded on error. It is possible strictly speaking from a mixture of
elhylic alcohol and ethylic aldehyde and acitone &c. to obtain by the condensation
of a part of the alcohol at a high temperature, a certain quantity of alcohol almost
entirely free from these very volatile bodies, but when commercial alcohols are treated
it is found that the greater part of the volatile compounds which accompany, the
alcohol in the products of fermentation are refractory to this means of separation.
Putting aside then processes dependent on differences of boiling point efforts have
been made to avoid the difficulty by the employment of chemical processes, the use
of carbon being included amongst these-Carbon, which is often employed, serves its
purpose sufficiently well especially as far as certain less volatile bodies are concerned
and certain imperfectly known products of peculiar odour and taste; but the greater
part of the chemical reagents have been successively abandoned because the mixture
to be treated being excessively complex the action of the reagents cannot be directed
solely upon this or that body to be eliminated, and at the same time that the
desired chemical re-action takes place others are produced which interfere with the
operation and often deteriorate the quality of the products.
Now it is evident that any intermediate operation having for its result a classifica-
tion of the different impurities will facilitate the employment of appropriate re-agents
to each distinct class. It will also have the further result of facilitating the sub-
sequent rectifications by allowing to be isolated and treated separately in each collected
series of alcohols such and such sorts of impurities to the exclusion of any other, or
at least will sufficiently modify the relative proportions of the different impurities
that the presence of a small quantity of certain of them may be practically without
importance. In other words, it will permit of the removal at each rectification a
larger proportion of pure alcohol.
This being understood I propose, according to my present invention, to proceed by
carrying on concurrently the two following operations, that is to say:
(1) Partial and successive distillations of concentrated products.
(2) Partial and successive condensations at high temperatures.
These two operations follow from the same physical law, the truth of which I have
verified in this particular case and which may thus be stated :-
There exists for each volatile body and for each temperature, in the presence of a
given solvent which does not act chemically on the body when brought to the same
temperature, a definite and fixed relation between the quantity of the body existing in
the form of vapours in a kilogramme of elastic uncondensed fluid and the quantity of
this same body dissolved in a kilogramme of the liquid."
This relation thus defined bereinafter termed the "partage coefficient," varies for
each body and generally increases very rapidly with the temperature, but it is not
possible to eliminate a volatile body from its solvent by distillation or partial con-
densation if the partage co-efficients are very close together. This relation for two
bodies in contact may be greater than unity at a given temperature and less at a
lower temperature. Now in this particular case the operation can be carried on at all
temperatures between 100 degrees and 79 degrees according to the state of concentra-
tion of the crude alcohol.
"
As it is especially required to eliminate the impurities called by distillers "corps
de tête
it is preferred to operate on crude alcohols which are sufficiently concentrated
to avoid trouble from impurities having a partage co-efficient less than unity at
temperatures near 80 degrees Centigrade; but weaker alcohols may be employed.

page_text: I will now proceed to describe in detail the process constituting my present
invention in which the apparatus herein after described and represented by the
annexed drawings is employed.
(I). PARTIAL AND SUCCESSIVE DISTILLATIONS.
I employ for my preliminary purifications alcohol of a certain degree of concentra-
tion obtained directly from an ordinary distillation column furnished with rectification
shelves; or obtained from the condensers of which I shall presently speak.
In the conditions in which I work the ordinary rules of distillation shew that a
half or two-thirds of the anhydrous alcohol contained in the liquid to be distilled may
be separated without any considerable alteration of the boiling point.
For example, if a liquid at 90° (Gay Lasac) be distilled so as to separate the half
of it, a residue at 87.7° will be obtained. If the original standard is 86° the residue
is still 80°. If the original standard is 60° the residue is 30°. In the first case the
boiling point rises from 79.1° to 79.2°; in the second case from 79.4° to 79.9°. In
the third from 81.7° to 85.7°. The values of the partage co-efficient of a given
impurity are then hardly modified when suitably concentrated alcohols are treated.
This constancy has enabled me to calculate what takes place when I submit alcohol
to a partial distillation such that half of it passes over in the state of vapour, and I
have experimentally verified the truth of my conclusions.
Employing a continuous distillation column, the walls of which were protected
from radiation, and passing into this column concentrated alcohol between 70°.
and 90° (G. L.) previously raised to its boiling point by the condensation of the
vapours emitted by the said column and distilling half of the alcohol treated I have
verified the following relation.
between the proportion S₁ of a certain impurity existing in a state of solution in
the liquid of the first upper shelf, the proportion Sm of the same impurity in the
liquid of the mth. shelf the partage co-efficient K corresponding to this impurity for
the temperature of the column, the proportion p in the vapours passing from bottom
to top from shelf to shelf, and the proportion P in the liquid circulating from top to
bottom.
To fix the ideas I will take an example :- Let the column have 20 shelves and let
the successive partage co-efficients have the values 5, 2, 1, .05, .02. The formula
gives the following values for the case of half the liquid being distilled :—

page_text: unity (and named " corps de tête") pass almost entirely into the products of dis-
tillation; whilst I obtained as non distilled residue alcohol containing almost alone
bodies having a partage co-efficient of separation smaller than unity and named
(corps de queue).
As to the impurities having the same partage co-efficient as the alcohol employed,
they are, as is seen in the above numerical example, in great part eliminated from the
residue if the number of shelves is sufficient. The larger the number of shelves the
more completely are the "tête" products eliminated, whilst the quantity of "queue"
products brought over is not materially modified.
This distillation column (fed with alcohol suitably concentrated) does not work as.
an ordinary.distillation column because there is not so to speak any expenditure of
liquid until its arrival into the vaporizing boiler. In the apparatus hereinafter
described the vapour traverses all the shelves without notable condensation and the
respective quantities of vapour and liquid remain approximately constant.
It should be observed that in this auxiliary distillation column it is useless to
introduce the complications usual in the ordinary column, namely, deflegmation
shelves and analyzers. These auxiliary elements inost important in the ordinary
column, would only uselessly increase the expenditure of fuel by increasing the
quantities of liquid in circulation without aiding appreciably in the purification.
In my apparatus where I treat concentrated alcohols .it is out of the question to
lower the temperature of the upper shelves by charging them with concentrated
alcohol it is useless to bring about a retrogradation it is simpler and more economical
to work upon the basis of modifying the production of vapour in the last compart-
ment or boiler. I therefore only interpose between the column and the condensers
a foam breaker or washer intended to keep back the liquids carried over mechanically,
returning these liquids to the first shelf.
By means of this auxiliary column I divide my crude alcohols into two lots, the
one deprived of bodies which have a partage co-efficient larger than unity under
the conditions of temperature in-which I am operating (this lot will furnish alcohol
de cœur "and tail products) the other principally charged with these bodies and
giving alcohols "de corps" and "de tête."
Partial and successive condensers. I effect the classification of the very volatile
components in my partial and successive condensers which I apply indeed to all
sorts of distillation and rectification apparatus.
In these condensers I aim at collecting the greater part of the alcohol at the
highest possible temperature so as to retain in the non condensed residue the
greater part of the more volatile impurities, and in the parts first condensed
the greater part of the less volatile impurities. This result is obtained by main-
taining the first condensers at a temperature of 77 to 79 Centigrade. At this
temperature a condenser with suitable surface area liquefies almost the whole of the
vapours of pure ethylic alcohol, more or less mixed with water; but in presence of a
gaseous atmosphere which cannot be condensed under the conditions of temperature
adopted, a part of the alcohol remains in the state of vapour and can only be
collected at a lower temperature; it escapes consequently charged with volatile
impurities. In continuing the condensation at temperatures less and less elevated,
all the alcohol is collected but the most volatile impurities attain a degree of con-
centration such that a part escapes in the gaseous state.
In a word the volatile. impurities are classed in each condenser according to their
partage co-efficient.
I employ then a series of condensers each maintained at a certain temperature
the first condenser at a temperature of 77 to 79 the second some degrees lower and
so on and finally an ordinary refrigerator.
Each of these condensers has a special outlet and the liquid collected can be
submitted either to another partial distillation or to an appropriate chemical treat-
ment or to rectification.
For the greater part of commercial alcohols I even divide each of the condensers

page_text: into a number of partial condensers or elements having each its special outlet. I
have in short ascertained that in each series of partial condensers submitted to the
same temperature and for all values of the partage ratio above unity_the rate per cent.
of non condensed impurities goes on increasing from one element to the next, and
that besides the rate per cent. of these impurities escaping from the action of the
entire series is more considerable than if a single condenser of the same power had
been employed in which the liquid collected had been maintained in contact with the
vapours.
Naturally the reverse takes place with the impurities of which the partage ratio is
smaller than unity.
By this division of each condenser into separate elements I am thus able to con-
dense on one side mainly the less volatile impurities and on the other the impurities
which are more volatile at the special temperature.
It is essential to appreciate the present invention to remark that I class as inore.
volatile" those bodies which most resist condensation under the special conditions of
temperature and as "less volatile" bodies, those which condense more easily without
making any reference to their specific boiling point which has no direct influence
upon the phenomena in question.
I naturally reserve to myself to maintain constant temperature in each series of
condensers by the known methods ordinarily employed and to deviate more or less
from the conditions of construction described below according to circumstances but
not departing from the principle of my invention.
The annexed drawings represent in a schematic form the apparatus referred to
above and which constitute the arrangements employed in putting into practice the
processes to which the preceding description applies.
Figures 1 and 2 represent the first a vertical section and the second a horizontal
section of one of the condensers in operation. These condensers consist of a tank A.
in which are arranged several series of long tubes T of a flattened elliptic section bent
to and fro in the same horizontal plane; the major axis of the ellipse being vertical→
this arrangement has for its object to increase the surface of contact between the
vapours and metal kept at the temperature of the tank. The whole is immersed in
the tank and inclined in such a manner that all the necks at one end may be at the
same level and those at the other extremity also at the same level slightly lower than
the first. Each couple of parallel contiguous tubes 1. 1. 2. 2. 3. 3. forms an element
and these elements communicate the one with the other by the lower part as is seen
in figure 2. The several elements continuous in the same horizontal plane form a
series.
Several series are arranged parallelly the one underneath the other in the tank
communicating the one with the other at the end so that the vapours after having
traversed the upper series traverse the next series below in the opposite direction.
After which the non condensed vapours are delivered into another tank kept at a
lower temperature and so on until the final refrigerator is reached.
Each element is furnished with an outlet tube of U form a making a hydraulic
joint and furnished with cocks which allow the outflow to be directed into one
or other of the collector tubes belonging to a corresponding receiver or to a guage
vessel.
As the alcohol vapours traverse all the successive series of a tank from top to
bottom, it is only requisite that all the elements of one series should be of the same
temperature and that the successive series of the same tank should be at temperatures
very near the one to the other the highest series being the hottest.
For this purpose I cause the water to circulate in the tank A. from bottom to top
and I cause it to pass out of the tank A. by a pipe B into the upper part of a
tubular refrigerator which it traverses from top to bottom whilst the crude alcohols
requiring to be heated brought in at the bottom of the capacity of the vessel C pass
in contact with the exterior faces of the tubes in rising from bottom to top from the
pipe D to the pipe E absorbing in their passage the heat brought in by the water
from the tank.
こう

page_text: The cooled water passes out by the pipe F which leads into the centrifugal pump G
the upper face of which is uncovered, so that it distributes equally all over the
bottom of the tank and regulates its circulation. To secure regularity in the opera-
tion I lead in by the cock R fixed upon the outside of the pipe F a supplementary
flow of water derived either from the next tank or from a reservoir of cold water.
An overflow L takes the excess of water from the refrigerator C either to a thermostat
which automatically regulates the admission of supplementary water or to a guage
vessel furnished with a thermometer and placed where it can be seen by the workman
who regulates at will the opening of the cock R. Finally a steam jet or a condensed
water supply enables the tank to be brought to the required temperature when
commencing work. These condensing apparatus are novel in construction and form
a part of the invention which I claim.
Figure 3 of the drawings shows the connection of the first condensers with the
auxiliary distillation column spoken of previously.
The crude alcohols partly heated by the waste heat pass through the tubular vessels C
commencing at the coldest and leaving by the outlet E of the last of the series to
enter upon the first shelf of the partial auxiliary distillation column N by the pipe E¹,
they traverse the column, which is an ordinary distillation column with shelves from
top to bottom, and finally they fall into a boiler M where they are caused to boil by
steam furnished by the valve V. The opening of this valve is regulated according to
the quantity of vapours to be separated. A thermometer placed upon the side of the
boiler shows the temperature of the vapours, and thus permits the regulation of the
operation.
On leaving the boiler the purified alcohols are at pleasure directed either into a
distillation column X where they are exhausted or into a refrigerator where their heat
is utilized this coming back to the ordinary process.
I naturally reserve to myself to apply batteries of condensers together with
analysers deflegmation columns or rectification columns of the ordinary sort
independently of the partial distillation column above described.
1 have established that the repetition of partial distillations and successive con-
densations cannot be applied indefinitely to the treatment of the more volatile products
obtained in the condensers the furthest removed from the apparatus producing the
vapour.
Indeed I have remarked above that in presence of a notable quantity of products
uncondensable at a given temperature, the greater part of the alcohol refuses con-
densation. It is suitable then at a given moment (to be selected according to the
nature of the alcohols under treatment) to endeavour to eliminate a part of the
impurities.
I have utilized to this end the property exhibited by a large number of these
bodies (grouped together by manufacturers under the name of ethers) to give with
oxide of lead, combinations which are insoluble in alcohol, and I have ascertained
that these combinations are best produced when the lead is used in the form of oxide
of plombire or of subacidate.
The addition of lead in one of these forms determines, either immediately or at the
end of a certain number of hours, the production of more or less turbidity, abundant
in the alcohols de tete or de cœur, but nothing but a simple precipitate of carbonate
of lead in the alcohols called "de cœur." It determines then the separation of
foreign bodies from pure alcohol.
But generally precipitation does not take place and the liquid remains cloudy and
cannot be filtered even after standing for a fortnight.
Such a mixture would be dangerous to distil for lead compounds might be carried
over mechanically by the current of vapours and the alcohol obtained would be quite
poisonous. 1 avoid this danger by a second operation which aids besides in the
purification.
The reaction being complete I introduce with heat a neutral chemical salt soluble
in alcohol, of which the base is capable of precipitation in a flocculent state by
alkaline bases or alkaline earths, or their carbonates.

page_text: The mixture is rapidly made in a closed vessel by a mechanical agitator, a pump
or a blower. Immediately afterwards I introduce during rapid movement the
precipitant previously measured according to the quantity of auxiliary salts introduced
including the salt of lead in solution.
The liquid immediately changes its appearance, a flocculent precipitate is formed
which takes up and coagulates the lead salt in suspension and takes it down with it.
The liquid containing the flocculent precipitate may be immediately passed into a
series of depositing vessels or filters and so obtain a crude alcohol or limpid phlegm
almost entirely disinfected or separated from the greater part of the "ethers" (this
word being taken in the general acceptation given to it by distillers) to be again
submitted to the operations above described.
The precipitate is collected and washed or heated in a distilling apparatus, the
intermediate reagent may be easily regenerated elsewhere and the lead remaining as
residue may be sold.
The use of this series of auxiliary operations which are much more economical than
successive rectifications permits the separation of crude alcohols or alcohols in course
of treatment into alcohols ready for rectification and residues suitable to be submitted
to a special chemical treatment.
D
ليوم
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1
1000
COMPLETE SPECIFICATION.
Improvements in the Treatment of Commercial Alcohols.
I, HUGUES ERNEST SOREL of 59 rue Bonaparte, Paris, in the Republic of France,
Gentleman, 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 :-
To purify crude alcohols obtained by a first continuous distillation a second inter-
mittent operation called rectification is employed, based in principle upon the notable
difference in volatility existing between the principal constituents of crude alcohols.
In this operation the crude alcohol, mixed with more or less water, is brought
gradually to the boiling point, and the current of vapour thus obtained is submitted
to a progressive cooling, the condensed products being constantly carried back and
the vapours which have escaped this partial condensation alone being collected.
It will be understood that the addition of water having raised the boiling point
of the crude alcohol the more volatile bodies contained in the crude alcohol will first
predominate in the vapours produced, and consequently in the liquids collected.
After the progressive disappearance of these comes an alcohol less charged with
volatile bodies; but the boiling point rising bodies which are less volatile than alcohol
appear little by little and finally predominate, when their progressive condensation
has sufficiently charged the shelves of the column, for them to acquire a notable
vapour tension, and the temperature of these shelves has risen in consequence of the
etheric alcohol leaving them.
If, as is done at present, the condensation of the vapours which escape from the
apparatus, is effected by a sudden cooling, and if the condensed products coming
from the different phase of the rectification are separated in special receivers a
series of products is obtained succeeding each other in the following order:
1. Dilute alcohol charged with very volatile principles (mainly aldehydes and
ethers).
2. Concentrated alcohol charged with a lesser proportion of all these products.
3. Alcohol practically (if not chemically) pure..
4. Concentrated alcohol, to some extent contaminated with less volatile principles.
5. Mere dilute alcohol saturated with less volatile principles.
6. Very weak alcohol (petites eaux) on which float less volatile principles but
slightly soluble in water (fusel oils).

page_text: After the separation of alcohol practically accepted as pure, the next thing is to
rectify the more impure alcohols which have been put aside; then an insurmountable
difficulty is encountered, namely: (1) that even the very volatile bodies do not
evaporate instantaneously but progressively together with their solvent, and con-
sequently contaminate a quantity of the product which becomes larger as the quantity
of volatile bodies existing in the liquid to be rectified increases. (2) That bodies less
volatile than ethylic alcohol, being concentrated with the residues of the first opera-
tions, soon acquire a vapour tension such that from the first they pass even into the
refrigerator so that it is very soon impossible to obtain even reasonable pure alcohol
by rectification,
Another difficulty is also often encountered a difficulty of another order the
ammoniacal salts and salts of organic bases existing in the greater part of crude
alcohols and even in refined alcohols are partially decomposable by heat and the bases
set at liberty react slowly upon the aldehydes still in solution to furnish nitrogenous
compounds, which are also slowly decomposable by hot water and consequently during
the entire rectification disengage aldehyde, which contaminates the condensed
products, and a part or the whole of the alcohol called "de cœur," the extraction of
which is the object of the rectification.
On the other hand the recombination of these volatile basic compounds and
aldehydes is, according to my personal experience, very slow and very difficult so
long as the bodies exist in the state of vapour; this admits of their separation by
means of the processes hereinafter described, consequently preventing the reformation
of these mixed compounds in the condensation products intended for re-rectification.
Many arrangements have in former times and recently been patented with the
object of utilising the difference which exists between the boiling points of the
impurities normally accompanying alcohol, to separate pure ethylic alcohol from these
impurities. Theory and practice are in perfect accord to shew that this basis of
operation is founded on error. It is possible strictly speaking from a mixture of
ethylic alcohol and ethylic aldehyde and acitone &c. to obtain by the condensation
of a part of the alcohol at a high temperature, a certain quantity of alcohol almost
entirely free from these very volatile bodies, but when commercial alcohols are treated
it is found that the greater part of the volatile compounds which accompany the
alcohol in the products of fermentation are refractory to this means of separation.
Putting aside then processes dependent on differences of boiling point efforts have
neen made to avoid the difficulty by the employment of chemical processes, the use
of carbon being included amongst these-Carbon, which is often employed, serves its
purpose sufficiently well especially as far as certain less volatile bodies are concerned
and certain imperfectly known products of peculiar odour and taste; but the greater
part of the chemical reagents have been successively abandoned because the mixture
to be treated being excessively complex the action of the reagents cannot be directed
solely upon this or that body to be eliminated, and at the same time that the desired
chemical re-action takes place others are produced which interfere with the operation
and often deteriorate the quality of the products.
Now it is evident that any intermediate operation having for its result a classifica-
tion of the different impurities will facilitate the employment of appropriate re-agents
to each distinct class. It will also have the further result of facilitating the
subsequent rectifications by allowing to be isolated and treated separately in each
collected series of alcohols such and such sorts of impurities to the exclusion of any
other, or at least will sufficiently modify the relative proportions of the different
impurities that the presence of a small quantity of certain of them may be practically
without importance. In other words, it wili permit of the removal at each rectification
a larger proportion of pure alcohol.
This being understood 1 propose, according to my present invention, to proceed by
carrying on concurrently the two following operations, that is to say:
(1) Partial and successive distillations of concentrated products.
(2) Partial and successive condensations at high temperatures.

page_text: These two operations follow from the same physical law, the truth of which I have
verified in this particular case and which may thus be stated :-
"There exists for each volatile body and for each temperature, in the presence of
a given solvent which does not act chemically on the body whena brought to the
same temperature, a definite and fixed relation between the quantity of the body
existing in the form of vapours in a kilogramme of elastic uncondensed fluid and the
quantity of this same body dissolved in a kilogramme of the liquid."
This relation thus defined hereinafter termed the "partage coefficient," varies for
each body and generally increases very rapidly with the temperature, but it is not
possible to eliminate a volatile body from its solvent by distillation or partial con-
densation if the pariage co-efficients are very close together. This relation for two
bodies in contact may be greater than unity at a given temperature and less at a
lower temperature. Now in this particular case the operation can be carried on at all
temperatures between 100 degrees and 79 degrees according to the state of con-
centration of the crude alcobol.
As it is especially required to eliminate the impurities called by distillers "corps
de tête" it is preferred to operate on crude alcohols which are sufficiently concentrated
to avoid trouble from impurities having a partage co-efficient less than unity at
temperatures near 80 degrees Centigrade; but weaker alcohols may be employed.
I will now proceed to describe in detail the process constituting my present
invention in which the apparatus hereinafter described and represented by the
drawings left with the provisional specification is employed.
1 employ for my preliminary purifications alcohol of a certain degree of con-
centration obtained directly from an ordinary distillation column furnished with
rectification shelves; or obtained from the condensers of which I shall presently
speak.
In the conditions in which I work the ordinary rules of distillation shew that
a half or two-thirds of the anhydrous alcohol contained in the liquid to be distilled
may be separated without any considerable alteration of the boiling point.
For example, if a liquid at 90° (Gay Lasac) be distilled so as to separate the half
of it, a residue at 87.7° will be obtained. If the original standard is 86° the residue
is still 80°. If the original standard is 60° the residue is 30°. In the first case
the boiling point rises from 79.1° to 79.2°; in the second case from 79.4° to 79.9°.
In the third from 81.7° to 85.7°. The values of the partage co-efficient of a given
impurity are then hardly modified when suitably concentrated alcohols are treated.
This constancy has enabled me to calculate what takes place when I submit alcohol
to a partial distillation such that half of it passes over in the state of vapour,
have experimentally verified the truth of my conclusions.
and I
Employing a continuous distillation column, the walls of which were protected
from radiation, and passing into this column concentrated alcohol between 70°
and 90° (G. L.) previously raised to its boiling point by the condensation of the
vapours emitted by the said column and distilling half of the alcohol treated I have
verified the following relation
between the proportion S₁ of a certain impurity existing in a state of solution in the
liquid of the first upper shelf, the proportion S of the same impurity in the liquid of
the mth. shelf the partage co-efficient K corresponding to this impurity for the
temperature of the column, the proportion p in the vapours passing from bottom to
top from shelf to shelf, and the proportion P in the liquid circulating from top to
hottom

page_text: To be the less I will ake an examph. Let the column have 20 shelves and lat
the successive partage co-efficients have the values 5, 2, 1, .05, .02. The formula
gives the following values for the case of half the liquid being distilled.
the successive partage co-efficients have the values 5, 2, 1, .05, .02. The formula
gives the following values for the case of half the liquid being distilled.
for K equal to 5
I
Sm
S₁ ×
2
242215
1
"
"
2 Sm
-
S₁ x
20
"
"
1 Sm
=
S₁ x
"
"
0.5 Sm
= S₁ ×
2.333
1
"
""
0.2 Sm
S₁ ×
2.111
5
These conclusions are confirmed by experience and I have verified that in the 1
above defined conditions all the impurities having a partage co-efficient greater than
unity (and named "corps de tête") pass almost entirely into the products of dis-
tillation; whilst I obtained as non distilled residue alcohol containing almost alone
bodies having a partage co-efficient of separation smaller than unity and named (corps
de queue).
As to the impurities having the same partage co-efficient as the alcohol employed,
they are, as is seen in the above numerical example, in. great part eliminated from
the residue if the number of shelves is sufficient. The larger the number of shelves
the more completely are the "tête" products eliminated, whilst the quantity of
queue" products brought over is not materially modified.
This distillation column (fed with alcohol suitably concentrated) does not work as
an ordinary distillation column because there is not so to speak any expenditure of
liquid until its arrival into the vaporizing boiler. In the apparatus bereinafter
described the vapour traverses all the shelves without notable condensation and the
respective quantities of vapour and liquid remain approximately constant.
It should be observed that in this auxiliary distillation column it is useless to
introduce the complications usual in the ordinary column: namely, deflegmation
shelves and analyzers. These auxiliary elements most important in the ordinary
column, would only uselessly increase the expenditure of fuel by increasing the
quantities of liquid in circulation without aiding appreciably in the purification.
In my apparatus where I treat concentrated alcohols it is out of the question to
lower the temperature of the upper shelves by charging them with concentrated
alcohol it is useless to bring about a retrogradation it is simpler and more economical
to work upon the basis ½ modifying the production of vapour in the last compart-
ment or boiler. I therefore only interpose between the column and the condensers a
foam breaker or washer intended to keep back the liquids carried over mechanically,
returning these liquids to the first shelf.
2
2
3
By means of this auxiliary column I divide my crude alcohols into two lots, the
one deprived of bodies which have à partage co-efficient larger than unity under the
conditions of temperature in which. I am operating (this lot will furnish alcohol de 4
coeur" and tail products) the other principally charged with these bodies and giving
alcohols "de corps" and "de tête."
Partial and successive condensers. I effect the classification of the very volatile
components in my partial and successive condensers which I apply indeed to all sorts
of distillation and rectification apparatus.
In these condensers I aim at collecting the greater part of the alcohol at the highest
possible temperature so as to retain in the non condensed residue the greater part of

page_text: he more volatile impurities, and in the parts first condensed the greater part of the
ess volatile impurities. This result is obtained by maintaining the first condensers at
temperature of 77 to 79 Centigrade. At this temperature a condenser with suitable
surface area liquefies almost the whole of the vapours of pure ethylic alcohol, more or
less mixed with water ; but in presence of a gaseous atmosphere which cannot be
condensed under the conditions of temperature adopted, a part of the alcohol remains
in the state of vapour and can only be collected at a lower temperature; it escapes
consequently charged with volatile impurities. In continuing the condensation at
temperatures less and less elevated, all the alcohol is collected but the most volatile
impurities attain a degree of concentration such that a part escapes in the gaseous
state.
In a word the volatile impurities are classed in each condenser according to their
partage co-efficient.
I employ then a series of condensers each maintained at a certain temperature the
first condenser at a temperature of 77 to 79 the second some degrees lower and so on
and finally an ordinary refrigerator.
Each of these condensers has a special outlet and the liquid collected can be sub-
mitted either to another partial distillation or to an appropriate chemical treatment or
to rectification.
For the greater part of commercial alcohols I even divide each of the condensers
into a number of partial condensers or elements having each its special outlet. I have
in short ascertained that in each series of partial condensers submitted to the same
temperature and for all values of the partage ratio above unity the rate per cent. of
non condensed impurities goes on increasing from one element to the next, and that
besides the rate per cent. of these impurities escaping from the action of the entire
series is more considerable than if a single condenser of the same power had been
employed in which the liquid collected had been maintained in contact with the
vapours.
Naturally the reverse takes place with the impurities of which the partage ratio is
smaller than unity.
By this division of each condenser into separate elements I am thus able to condense
on one side mainly the less volatile impurities and on the other the impurities which
are more volatile at the special temperature.
"
* more
It is essential to appreciate the present invention to remark that 1 class as
volatile" those bodies which most resist condensation under the special conditions of
temperature and as less volatile" bodies, those which condense more easily without
making any reference to their specific boiling point which has no direct influence
upon the phenomena in question.
I naturally reserve to myself to maintain constant temperature in each series of
condensers by the known methods ordinarily employed and to deviate more or less
from the conditions of construction described below according to circumstances but
not departing from the principle of my invention.
The drawings represent in a schematic form the apparatus referred to above and
which constitute the arrangements employed in putting into practice the processes to
which the preceding description applies.
Figures 1 and 2 represent the first a vertical section and the second a horizontal
section of one of the condensers in operation. These condensers consist of a tank A
in which are arranged several series of long tubes T of a flattened elliptic section bent
to and fro in the same horizontal plane; the major axis of the ellipse being vertical-
this arrangement has for its object to increase the surface of contact between the
vapours and metal kept at the temperature of the tank. The whole is immersed in
the tank and inclined in such a manner that all the necks at one end may be at the
same level and those at the other extremity also at the same level slightly lower than
the first. Each couple of parallel contiguous tubes 1. 1. 2. 2. 3. 3 forms an element
5 and these elements communicate the one with the other by the lower part as is seen
in figure 2. The several elements continuous in the same horizontal plane form a
series.

page_text: .
Several series are arranged parallelly the one underneath the other in the tank
communicating the one with the other at the end so that the vapours after having
traversed the upper series traverse the next series below in the opposite direction.
After which the non condensed vapours are delivered into another tank kept at a
lower temperature and so on until the final refrigerator is reached.
Each element is furnished with an outlet tube of U form a making a hydraulic
joint and furnished with cocks which allow the outflow to be directed into one or
other of the collector tubes b belonging to a corresponding receiver or to a guage
vessel.
As the alcohol vapours traverse all the successive series of a tank from top to
bottom, it is only requisite that all the elements of one series should be of the same
temperature and that the successive series of the same tank should be at temperatures
very near the one to the other the highest series being the hottest.
For this purpose I cause the water to circulate in the tank A from bottom to top
and I cause it to pass out of the tank A by a pipe B into the upper part of a tubular
refrigerator which it traverses from top to bottom whilst the crude alcohols
requiring to be heated brought in at the bottom of the capacity of the vessel (pass
in contact with the exterior faces of the tubes in rising from bottom to top from the
pipe D to the pipe E absorbing in their passage the heat brought in by the water
from the tank.
The cooled water passes out by the pipe F which leads into the centrifugal pump G
the upper face of which is uncovered, so that it distributes equally all over the
bottom of the tank and regulates its circulation. To secure regularity in the operation
I lead in by the cock R fixed upon the outside of the pipe F a supplementary flow of
water derived either from the next tank or from a reservoir of cold water.
An over-
flow L takes the excess of water from the refrigerator C either to a thermostat which
automatically regulates the admission of supplementary water or to a guage vessel
furnished with a thermometer and placed where it can be seen by the workman who
regulates at will the opening of the cock R. Finally a steam jet or a condensed
water supply enables the tank to be brought to the required temperature when com-
mencing work. These condensing apparatus are novel in construction and form a
part of the invention which I claim.
Figure 3 of the drawings shews the connection of the first condensers with the
auxiliary distillation column spoken of previously.
The crude alcohols partly heated by the waste heat pass through the tubular
vessels commencing at the coldest and leaving by the outlet E of the last of the
series to enter upon the first shelf of the partial auxiliary distillation column N by the
pipe E¹, they traverse the column, which is an ordinary distillation column with
shelves from top to bottom, and finally they fall into a boiler M where they are
caused to boil by steam furnished by the valve V. The opening of this valve is
regulated according to the quantity of vapours to be separated. A thermometer
placed upon the side of the boiler shews the temperature of the vapours, and thus
permits the regulation of the operation.
On leaving the boiler the purified alcohols are at pleasure directed either into a
distillation columa X where they are exhausted (i.e. the alcohol is separated) or
into a refrigerator where their heat is utilized this coming back to the ordinary
processes.
I naturally reserve to myself to apply batteries of condensers together with
analyzers deflegmation columns or rectification columns of the ordinary sort inde-
pendently of the partial distillation column above described.
I have established that the repetition of partial distillations and successive con-
densations cannot be applied indefinitely to the treatment of the more volatile products
obtained in the condensers the furthest removed from the apparatus producing the
vapour.
Indeed have remarked above that in presence of a notable quantity of products
uncondensable at a given temperature, the greater part of the alcohol refuses con-
densation. It is suitable then at a given moment (to be selected according to the

page_text: nature of the alcohols under treatment) to endeavour to eliminate a part of the
impurities.
I have utilized to this end the property exhibited by a large number of these bodies
(grouped together by manufacturers under the name of ethers) to give with oxide of
lead combinations which are insoluble in alcohol, and I have ascertained that these
combinations are best produced when the lead is used in the form of oxide or in the
form of plombite of potash or soda or of subacitate.
The addition of lead in one of these forms determines, either immediately or at the
end of a certain number of hours, the production of more or less turbidity, abundant
in the alcohols de tête or de cœur, but nothing but a simple precipitate of carbonate
of lead in the alcohols called "de cœur." It determines then the separation of foreign
bodies from pure alcohol.
But generally precipitation does not take place and the liquid remains cloudy and
cannot be filtered even after standing for a fortnight.
Such a mixture would be dangerous to distil for lead compounds might be carried
over mechanically by the current of vapours and the alcohol obtained would be quite
poisonous. I avoid this danger by a second operation which aids besides in the
purification.
The reaction being complete I introduce with heat a neutral chemical salt such as
chloride of magnesium or chloride of manganese soluble in alcohol, of which the base
is capable of precipitation in a flocculent state by alkaline bases or alkaline earths, or
their carbonates.
The mixture is rapidly made in a closed vessel by a mechanical agitator, a pump or
a blower. Immediately afterwards I introduce during rapid movement the precipitant
previously measured according to the quantity of auxiliary salts introduced including
the salt of lead in solution.
The liquid immediately changes its appearance, a flocculent precipitate is formed
which takes up and coagulates the lead salt in suspension and takes it down with it.
The liquid containing the flocculent precipitate may be immediately passed into a
series of depositing vessels or filters and so obtain a crude alcohol or limpid phlegm
almost entirely disinfected or separated from the greater part of the "ethers" (this
word being taken in the general acceptation given to it by distillers) to be again
submitted to the operations above described.
The precipitate is collected and washed or heated in a distilling apparatus, the
intermediate reagent may be easily regenerated elsewhere and the lead remaining as
residue may be sold.
The use of this series of auxiliary operations which are much more economical than
successive rectifications permits the separation of crude alcohols or alcohols in course
of treatment into alcohols ready for rectification and residues suitable to be submitted
to a special chemical treatment.
Having now particularly described and ascertained'the nature of my said invention
and in what manner the same is to be performed, I declare that what I claim is the
three improvements introduced into the treatment of commercial alcohols constituting
the combined process described: that is to say-
1. Partial distillation in a continuous distillation column of the crude phlegms or
alcohols in course of manufacture more or less diluted with water, so as to separate
these phlegms or alcohols into vaporised products containing principally the more
volatile constituents of the mixture. and non vaporised products containing principally
the less volatile constituents, substantially as described.
2. Application to distilling apparatus and to rectifiers, of condensers forming
series, each maintained at a constant temperature, each condenser of each series
having its separate outlet substantially as described and represented in the annexed
drawings.
3. Successive additions to the crude phlegins or alcohols in course of treatment of a
composition of oxide of lead, then of a salt soluble in alcohol and capable of being

page_text: precipitated in flakes by magnesia, lime, the alkalies or the alkaline carbonates and
finally one of these reagents; this succession of chemical operations having for its
object the combination into a filterable precipitate, of a part of the ethers and
analogous bodies in the manner and with the object substantially as described.
Dated this 22nd day of August 1889.
CARPMAEL & Co.,
Agents for the Applicant.