Improvements in the Manufacture of Acetone, and in Apparatus therefor.
Year: 1894

page_text: Date of Application, 3rd Dec., 1894
Complete Specification Left. 6th June, 1895-Accepte1, 5th Oct.,
1895
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Acetone, and in Apparatus
therefor.
We, ROLOF JÜRGENSEN, Doctor of Philosophy, of Smetanka 6 Prague
(Weinberge), and AUGUST BAUSCHLICHER, Chemist, of Zhirow, both in Bohemia,
in the Austro-Hungarian Empire, do hereby declare the nature of this invention
to be as follows:-
The manufacture of acetone was heretofore accomplished by the destructive
distillation of neutral acetates, especially acetate of lime, either in tubular retorts
or in pan-shaped vessels under exclusion of air and with direct firing.
At these processes considerable impurities are produced which impair the yield
of acetone and affect the purity of the crude acetone in a high degree.
The object of this invention is, to furnish an improved process by which the
formation of secondary decomposition products is to a considerable extent obviated,
an improved quality of crude acetone is obtained and a much higher yield of pure
acetone.
We have discovered, that the formation of secondary decomposition products is
obviated to a considerable extent by submitting basic acetates, and especially
basic acetate of lime, to destructive distillation, instead of neutral acetates as
heretofore done.
The basic acetates, especially the basic acetate of lime, are to be obtained
in the required quality only by mixing a solution of neutral acetates with calcium
hydrate, say 5 per cent., in the shape of milk of lime, as soon as the solution has
evaporated sufficiently to assume a pasty condition. The mixture then is to be
dried perfectly.
The basic acetate of lime is to be treated for making acetone by destructive
distillation, but to assist the distillation,-to prevent any chance of decomposition-
to get a yield of purest acetone coming nearest to the theoretical yield-a constant
heat, under admission of inert gases, such as generator gas, water gas or super-
heated steam of uniform temperature, is afforded in a special arrangement for the
destructive distillation.
Our invention for this arrangement is to accomplish the destructive distillation
by a bath of molten lead, using a closed mixing vessel formed of an exterior and
interior pan-shaped vessel, the space or jacket between which is filled with molten
lead keeping the charge in the vessel at the required constant temperature. The
contents of the mixing vessels are discharged, when the process is completed, by
the agitator through a discharging spout.
Care should be taken, of course, for an arrangement to prevent the direct
contact of the flame with the bottom of the mixing vessel and to secure the
uniform distribution of the fine gases around the lead of the mixing vessel.
The generator gas, water gas, or superheated steam applied to the mixing vessel
during the entire operation envelopes the acetone vapours and facilitates their rapid
escape and prevents the formation of decomposition (bye-) products.
The aretone vapours pass from the mixing vessel through a system of connecting
tubes into a collecting vessel which retains the dry, fine particles of lime--alts
which are carried over by the acetone vapours, and prevents thereby the choking
up of the connecting tubes and the condenser. The collecting vessel is provided

page_text: with a steam heating coil at the bottom, to pass the volatile products into the
condenser, where they are condensed to crude acetone; the said permanent gases
may be led to the furnace of the mixing vessel and serve as fuel.
The crude acet ne obtained by our process is of a high degree of purity com-
pared with acetone made in the ordinary way. It is mixed with water and after
the impurities have separated, it is subjected to distillation only once, in a suitable
vertical rectifying apparatus. The distillate obtained is chemically pure acetone
containing 99-8-100 per cent. of acetone which evaporates from 56 to 58° Celsius;
the yield of this acetone is very near to the theoretical yield.
The impurities which are obtained by the destructive distillation of the acetates
and during the initial and final runs of the rectification process could not heretofore
be properly utilized. By the following process, however, these bye-products or
acetone oils can be utilized and converted into acetone which is well adapted for
technical purposes.
While it is not possible, to convert the acetone oils by direct distillation, our
improved process admits a yield of from 50 to 70 per cent. of water-soluble acetone
from the same, evaporating from 56-65° Cel. For this process the acetone oils
are mixed with water and allowed to stand for several days, while subjected to
pressure and occasional stirring. For some oils a slight acidulation will be
preferable. The entire mixture is then distilled with steam in a suitable rectifying
apparatus. The distillate is acetone evaporating from 56-65 Celsius. In place
of permitting the acetone oils to stand with water for a few days, they can also be
mixed by means of an injector which is operated by steam and forced into the
boiler of the distilling and rectifying apparatus containing water. During the
injection of the oils into water the connection of the rectifier with the condenser is
closed; but as soon as a maximum pressure is obtained, the injection of oils is
stopped, the communication with the condenser slowly opened, and the distilling
process started with the result obtained as before described.
Dated this 3rd day of December 1894.
FAIRFAX & WETTER,
Agents for the Applicants.
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Acetone, and in Apparatus
therefor.
We, ROLOF JÜRGENSEN, Doctor of Philosophy, of Smetanks 6, Prague,
(Weinberge), and AUGUST BAUSCHLICHER, Chemist, of Zbirow, both in Bohemia,
in the Austro-Hungarian Empire, do hereby declare the nature of this invention
and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :-
The manufacture of acetone was heretofore accomplished by the destructive
distillation of neutral acetates, especially acetate of lime, either in tubular retorts
or in pan-shaped vessels under exclusion of air and with direct firing.
Working the process in this way, considerable quantities of secondary products
of decomposition are produced at the expense of pure acetone, which products are
dissolved by the crude acetone formed in the process, so as to contaminate the same,
and some pass even into the purified acetone.
The present invention has for its object, to avoid the generation of these products
of decomposition, to obtain a highly pure quality of crude acetone and subsequently
in quantity chemically pure acetone which almost equals the theoretical yield
(being about 90-95 per cent. of the same).
For this purpose we employ as a raw material neutral acetates, preferably
acetate of lime, which contain bydrates of alkalies, or of alkaline earths or of

page_text: magnesia, and produce the said raw material fr un an aqueous solution of neutral
acetates, preferably of calcium acetate (when it has been boiled down sufficiently
to assume a pasty condition), by adding to the acetates in said pasty condition a
certain quantity of hydrate of alkalies, or of alkaline earths or of magnesia,
preferably hydrate of calcium in the shape of milk of lime, mixing the ingredients
thoroughly, and then drying the mixture. 100 parts of acetate require about
5 parts of caustic lime or the corresponding quantity of calcium hydrate in the
shape of milk of lime.
We have found, also, that the purity of the crude acetone produced in this
process depends on keeping an extremely uniform temperature during the process
of destructive distillation of the acetats, and on the complete prevention of any
chance of superheating the vessel or retort containing the acetates, and conse-
quently of decomposition of the acetone vapours formed by destructive distillation
of the acetates. For this purpose, to keep the vessel or retort in which the
destructive distillation is performed, at a perfectly constant temperature, we heat
this vessel by a bath of molten lead, kept in molten condition by the fire of a
furnace below, and promote the rapil escape of the newly formed acetone
vapours, to avoid their becoming decomposed in contact with the walls of the
vessel, by admitting inert gases or vapours into the upper part of the acetone
retort or vessel.
For carrying out our process, we employ an apparatus chiefly consisting of a
jacketed hermetically closed retort or vessel provided with a rotary stirrer, said
vessel being set in masonry over a fireproof arch and heated by a furnace below.
and being hermetically connected with a dust collector and a condenser by means
of wide tubes.
Such an apparatus is illustrated by the accompanying diagrams,
Fig. 1 being a vertical cross section,
Fig. 2 a vertical longitudinal section,
Fig. a plan of the entire plant, while
for the
Fig. 4 is a horizontal section of the retort setting above the brick arch.
The destructive distillation of the acetates mixed with hydrates of alkalies or
alkaline earths as described above, is effected in a jacketed iron retort A provided
with an airtight covering B, which has a manhole a and a stuffing box =
vertical shaft X of a two-armed stirrer b. The latter has knife-shaped arms,
rotating close to the bottom of the retort, and is adapted to move the acetates,
mixing and revolving the same during the process. The inner space between the
walls of the retort is filled with molten lead. The retort or still is set in masonry
and heated by means of a grate q. To prevent unequal heating of the retort by
the flame arising from the furnace, the latter is covered with a vault d having
small openings like a gridiron, adapted to uniformly distribute the products of
combustion, before they reach the bottom of the jacket containing the molten
lead. The lead, which is always heated uniformly, maintains the interior of the
retort, and so the acetate contained in it, at a uniform temperature. An important
advantage of the highly heated firebrick arch consists in the fact, that its radiant
heat prevents the cooling of the lead-jacket, while the residue of the process of
distillation (consisting chiefly of carbonates) is discharged, which discharge can
only take place after the fire has been removed from the grate; owing to the
retention of heat by the firebrick arch, the distillation of a new charge of acetate
introduced into the retort through the manhole a immediately after the retort has
been emptied, may already commence with just the temperature necessary for the
normal and uniform working of the process.
For discharging the residual contents from the retort, after the process has
finished, we provide at the bottom of the retort and passing the jacket and the
masonry, a short discharge tube cast in one piece with the inner walls of the
retort, which tube is to be closed by a valve e, the said residue being moved into
the said tube automatically by the motion of the stirrer, when the valve e is
withdrawn, and passing by the same to the out-ide.

page_text: To prevent the decomposition by superheating, of the acetone vapours generated
by the destructive distillation, and to avoid the formation of products of con-
densation (in the chemical sense) we admit inert gases, such as generator gas,
carbonic oxide or aqueous vapour, at a suitable and constant temperature from an
open coil g into the upper part of the acetone retort, thereby causing the acetone
vapours which have been formed, to be enveloped by the said gases, and facilitating
the same to escape rapidly from the spot or zone, where they might be decomposed,
through the connecting pipes.
To ensure, that the said inert gases or the steam conducted into the retort may
also have the required constant temperature, we conduct the said gases, immediately
before their admission into the retort, through a superheating coil / situated in the
furnace fluc, so as to be maintained at a constant temperature of about 300° C. by
the waste gases arising from the furnace.
In heating the superheater directly by fuel on a grate, considerable fluctuations
of the temperature of the gases flowing through the superheater would be almost
inevitable, even with careful treatment.
The products of distillation leaving the generating retort A escape through a
system of wide connecting tubes k-k³, the ends of which are covered with
detachable covers, to facilitate the removal of the dust-shaped salts which have
been carried over with the vapours and then deposited in the tubes. From ³ the
vapours pass through tube k into an iron cylinder C provided with a steam heating
coil and discharge pipe, and serving to deposit the salts carried over in the shape
of dust, which otherwise might choke the connecting pipes. From the cylinder C
the volatile products pass through a system of wide connecting tubes 5-k into
the condenser, to be condensed as crude acetone. The permanent gases, such as
generator gas, which were admitted into the upper part of the acetone retort by
the open coil, pass the condenser as the same and are recovered; they may be
again utilised in the process by conducting them into the combustion chamber J,
to heat the jacket filled with molten lead.
The crude acetone obtained as described is mixed with water in a closed
receptacle, to relieve it from any tarry or oily particles that may be dissolved or
suspended in it. The mixture having stool for some time, the tarry and oily
particles have st parated on the surface. The aqueous acctone solution deposited
as a clear liquid is rectified once in a suitable column--till, thereby yielding the
whole of the acetone contained in the aqueous solution, in the quality of chemically
pure acetone (99.5 per cent.), which answers the highest requirements as regals
purity for use in the manufacture of smokeless powder.
The quantity of chemically pure sectone thus obtained, about 99 per rent. of
which distil over between 56 and 57° C, is from 25 to 26 kilo-, for every 100 kilos.
of ordinary connnercial grey Lectate of lime.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim i---
ม
1. The process of manufacture of aretone, which consists in subjecting
mixture of acctates with hydrates of alkalis or of alkaline earths or of magnesia,
to destructive distillation in a hernetically closed retort or vessel provided with a
rotary double-armed stirrer and heated by means of a metal bath, and admitting
to the upper part of the interior of the said retort a current of inert gas, such as
generator gas, carbonic oxide or superheated steam, at a constant temperature, to
avoid decomposition and to facilitate the escape of the acetone vapours, conducting
the latter into a closed vessel provided with a steam heating coil, to deposit the
solid or dust-shaped particles carried along by the vapours, and subsequently
conducting the vapours and gases into a cooler for the condensation of the acetone
vapours into liquid crude acetone.
2. The process of manufacture of acetone described, which consists in subjecting
a mixture of an acetate with an alkali-hydrate or its substitute to destructive

page_text: istillation in a hermetically closed and uniformly heated retort containing an
gitator, admitting during the process into the upper part of the interior of the
etort a current of inert gases adapted to facilitate the escape of the acetone
apours by the connecting tubes into a separator for depositing the solid particles,
onducting the acetone vapours into a condenser, and utilising the recovered inert
ases coming from the condenser as a fuel for heating the retort.
3. The purification of the crude acetone obtained substantially as set forth, by
ixing the same with water, allowing the mixture to stand, and rectifying the
eposited clear aqueous acetone solution obtained after the separation of any traces
tarry and oily matter, in a suitable column still, for the purpose of obtaining
hemically pure acetone having a boiling point between 56 and 57° C.
4. Apparatus for making acetone, substantially as set forth, consisting in its
onstruction of
a, a retort or vessel A having a jacket of molten lead heated from a furnace
below, and a discharge tube provided with a valve e, an open pipe
coil communicating with a superheater h (for admitting inert gases into
the process) adapted to be heated by the waste gases from the retort furnace,
and a fireproof vault d provided with numerous openings for the admission
of the heating gases from the furnace to the retort;
b, a hermetically closed cover B provided with manhole a and outlet tube k,
and a mechanical rotary stirrer b with double arms adapted to revolve over
the bottom of the vessel or retort and to mix and scrape the contents of
the same;
c, an airtight cylinder C containing a closed steam heating coil, and a discharge
pipe, for the purpose of depositing the dust shaped salts carried with the
distillate through the connecting system of pipes k―k;
d, a condenser D ;
e, a system of wide tubes k to k² connecting the various receptacles and
provided with easily detachable covers adapted to facilitate the cleansing of
the tubes.
Dated this 5th day of June 1895.
FAIRFAX & WETTER,
433, Strand, London, Agents.