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July 9, 1946- , >
I. L. ,MURRAY ET AL
2,403,742
‘PROCESS FOR MAKING‘ BUTADIENE
Filed Sept. 9, 1943
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INVENTORS
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lRVlN L. MURRAY
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$6145 2'1 QFAISFH JR
BY
ATTORNEY
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Patented July 9, 1946
2,403,742
" f ui-mlrso-"srA'r-ss PATENT ‘OFFICE
» PROCESS FOR ~MAKING ,BUTADIENE
Irvin L. .Murray, “Charleston, and Jay L. Marsh,
South Charleston, W. Va., and Silas vP. Smith,
JL, ‘Louisville, Ky, assignors to Carbide and
Carbon Chemicals Corporation, a corporation
‘of New York‘
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Application-September 9, 1943, Serial No. 501,611
~ 8' Claims.‘ (omen-cs1) ’
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This invention relates to a process for making
butadiene from ethanol.
According
to
this
condensed. Any permanent gases produced'in
.
the reaction, .or present in ‘the reaction products,
also, ‘contain the vapors of vthis condensate,
invention, ‘ butadiene is
formed from ethanol in twosteps, one step being
namely,‘ acetaldehyde, ethanol, Water and by
the conversionof ethanol to acetaldehydein ,a
products. . The valuable constituents may be re
separate reaction, and the other step beingthe
covered fromjthese gases by compressing .the
separateconversibn to butadiene of a mixture
- of theacetaldehyde formedin' the ?rst stepivand
, gases andscrubbing them with water.
In the second step of the process, ethanol and
'acetaldehyde, preferably in 'the'm‘olar' ratio of
ethanol. Both reactions are carried outginthe
vapor‘phase, Although; some savingsin the total
about 3vto 1, are reacted 'inithe' vapor .state in the
heat required vto operate both. steps, of the'process
may'be obtained by introducingthe-gaseous re
action products-from the i acetaldehyde converter
directly into» the butadiene converter, greater ad
vantages. in economyw-and ease of operation are
obtained bythe process of thisinvention. ‘ In‘ this
invention,‘ the products from both the; acetalder
hyde and the butadiene converters arezseparated
from permanent gasesproduced- in, the reactions,
the butadiene is separated from any unreacted
ethanol and acetaldehyde, and thevpmaterials re
presence of suitablej_.catalystsf to form butadiene.
A preferred catalystis described in .W. J. Tons
saint and ‘J. 'I'.v , Dunn application Serial‘v No.
‘$60,120, ?led September 29, 1942. Other catalysts
1:5. for ‘this reaction are, reported ‘in the vliterature.
‘Theie?luentvaporszand gases. from the buta‘die'ne
converter,_containing butadiene, ethanol, acet—
aldehyde, diethyl'ether, ethylene, propylene and
saturated hydrocarbon gases, and other by-p'ro'ds
maining from these separations, containing », eth -,
anol, acetaldehyde and by-products areintro
duced to a common distillation system.. This dis
tillation system removes the by-products pro
duced‘in both‘ reactions and supplies ethanol to
the acetaldehyde' converten; andv ethanol and
acetalde'hydeto the *butadiene converters,’ Thus,
the‘ entire process is Operated-i113 cyclicand con
tinuous; manner. EthanoLequivalent to, that con- ‘
nets are. passed throughfa condenser.
Most of
the vapors are condensed in this operation, but ,
alargeffraction of the butadiene ‘is notlique?ed
and suchjfract'ion is presentin the gases. leaving
the condenser. ,‘The butadiene' may be recovered
from. such gases by compressing the gases and
scrubbingthem'lwith a solvent, such as ethanol.
Howeveneconomyin operation maybe obtained
by employing. as the scrubbing liquid a material
which ‘is to be'subjected to distillation 'inany
event as described in the copending application,
sumed in the process, is. supplied to the system,.
v‘fProcess'_ for \ making butadiene,” ~ Serial No.
preferably'as reflux'in a distillation column in
501,610, of I, L.,,Murray, J. L. Marsh and ‘S. P.
which ethanol vaporsare beingremoved. How
:Smi‘th,;Jr. Such‘ a material ‘is the condensate of
ever, make-up ethanol may be supplied in "any
ethanoland acetaldehyde from the acetaldehyde
other convenient manner. ,For instancait'may ':* reaction. Alternatively, the make-up ethanol re
beadded ; as scrubbing liquid to separate buta
quired in the process-may be employed as scrub
diene ‘from. other gases of lower boiling point.
The process of" this invention has theadvantae'e
.Asubsequentscruhbing tower may be provided
that,“ by providing ‘appropriate storage " facilities
‘tore'cover thevapors of the scrubbing: liquid: from
thelgasesleavingthe butadiene scrubbing tower.
for the crude productsof eachreaction; each re
action may be conducted independently. IA, fur-7
Watefisasuitabl'e scrubbing liquid for use in this
ther ' advantageis that'iboth reaction systems’ uti
lize ‘the same distillation system‘ for the recovery
The ?rst condensate from the butadiene‘ reac
hing. liquid.
second tower.‘
‘ofhnconverted materials, which provides econ
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tion andlthe liquid. e?lux from the scrubbing'tower
may in "the equipmentrequ-ired to operate the (-1 win whichibutadieneis removed from other gases
are mixed ‘and treatedto recover’ the butadiene.
process.v
‘ Inthe ?rst stepgof
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.r the
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process,
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ethanol vapors
This. may be accomplished by a distillation proc
are passed to‘a reaction; zone, and a part of such
ess, in which butad-iene is removed as a head
vapors'convertedxto acetaldehyde by any of the
product along with some acetaldehyde. _ The
‘known methods.
These, methods
include dehy- :
I
drogenation of the ethanolto acetaldehyde in the
presence of dehydrogenation catalysts, or the
‘catalytic oxidation ofrethanol, toacetaldehyde-by
molecular oxygen; ' The‘products from .thisireac- ‘
vtion ‘containing ac'etaldehydeandyethanolqare 55;
acetaldehyde may be removed by scrubbing the
,butadiene vaporswith Water, and the l'butadiene
maybe puri?ed‘, if necessary, by known methods. >
The condensatesstill residuesand liquid scrub
‘ber products from the previousv operations which
contain all the effluent materials" ofboth reaction
2,403,742’
4
3
systems with the exception of butadiene, hydro
carbon impurities associated with the butadiene,
and the permanent gases, are subjected to a series
of distillations. The streams remaining after the
separation of butadiene and other gases contain
ethanol, acetaldehyde, water, and by-products,
such as diethyl ether, which is formed in the bu
tadiene reaction, and miscellaneous by-Products
.
verter need not be operated at undesirably high
' pressures in order to compensate for the pressure
drop through both converters.
If such high pres
sures were maintained, the yield of acetaldehyde
by the dehydrogenation of ethanol would be de
creased. The alternative to this, in which com
pressors are provided between the acetaldehyde
. converter and the butadiene converter, would
greatly increase the cost of the installation and
ethy1 acetate, acetic acid and butyraldehyde. 10 would make operation of the process more com
plex.
The distillation system removes suf?cient of the
In addition, they passage of the 'by-products
by-products to prevent their accumulation in the
from the acetaldehyde reaction, including hydro
cyclic system, and recovers ethanol and acetalde- -.
gen, through the butadiene converter might tend
hyde for passage to the acetaldehyde and buta
to injure the butadiene catalyst, reduce the yield
diene reaction systems. One method by which
of butadiene, or form other lay-products trouble
of the acetaldehyde-forming reaction, such as
this may be accomplished is to provide a series
of stills adapted to remove the components in the
order of their volatility. The ?rst column in such
a series removes acetaldehyde from the feed for
some to remove.
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Suitable apparatus and operating conditions
for practicing the process described above will
now be described with reference to the attached
passage to the butadiene converter. The acet 20 drawing but the invention isnot restricted to
aldehyde distills as its azeotropic mixture with
these specific embodiments. All proportions
diethyl ether, boiling at about 57° C. at 40 p. sci.
speci?ed are by weight.
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gauge pressure and containing approximately
Ethanol vapors alOng with about 10% water
75% acetaldehyde and 25% diethyl ether. Rela
tively large amounts of diethyl ether thus accu
mulate in the cyclic system and are recirculated
through the butadiene converter. This tends to
prevent the formation of additional amounts of
diethyl ether in the reaction.
,
The residue from this distillation passes to an
other continuous column where the lay-products
are removed as a heads product containing a mix
‘ture of binary and ternarygazeotropes involving
vapor are introduced to a converter ID of the
shell-and-tube type, through a pipe I I, after pass
ing through a heat exchanger 12., The converter
contains a copper catalyst‘ at a temperature of
about 280° C. and part of the ethanol is dehydro
genated to acetaldehyde in passing over this cat
alyst. The converter may be heated by circu
lating a high-boiling organic liquid through heat
ing elements in the converter. ~The vapors leave
the bottom of the converterthrough a' pipe l3,
acetaldehyde, water, diethyl ether, ethyl acetate,
pass through the ‘heat exchanger l2 used to pre
butyraldehyde and otherimpurities. A batch still 35 heat the feed, and pass through a pipe I4 to a
may be provided for the periodic recovery from
condenser |5,‘in which most of the vapors are
the by-prcducts of the materials employed in the
condensed.
process.
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The uncondensed vapors, the gases and the
The residue from the by-products removal still,
condensate pass through a pipe I E to a separating
consisting largelyv of ethanol and water, passes to 40 ' tank IT, in which’ the condensate collects at the
an alcohol still operated under pressure, which
bottom. The uncondensed vapors and gases con
generates an azeotropic mixture of ethanol and
taining acetaldehyde, ethanol, water and hydro‘
‘water for feeding both reaction systems. The
gen pass from the top of the tank through a pipe
water removed as a residue is customarily used 7
l8 to a compressor [9, where they are compressed
for heating purposesv before being discarded.
to a pressure of about 55 p.‘ s. i. The compressed
Thus, it may be employed for heating the feed to
vapors and gases pass through a condenser 20,
the still in which acetaldehyde is removed and
from which they are introduced through a pipe
‘the feed to the still in which butadiene is re
2| to the base of a scrubbing tower 22. ‘Here,
moved.
the water-soluble vapors are dissolved'and re
Various methods of removing by-products,
-moved from the hydrogen by means of scrubbing
other than as indicated, may also be practiced,‘
water, and the liquid effluent flows through pipe
as by withdrawing by-products from plates in the
23 to the recovery distillation system.
butadiene, acetaldehyde, by-products, and eth
The chemical reaction producing butadiene is
iuti’ol column, in which such by-produ'cts accumu
conducted concurrently with that producing ac
a e.
etaldehyde In this second chemical reaction, a
Other arrangements of the distillation series
mixture of ethanol and acetaldehyde vapors,
may be carried out in which the materials to :be
preferably in the molar ratio‘ ‘of about 3 to 1, is
separated are divided into two or more fractions,
passed through a heat exchanger 24 through a
and such fractions treated to isolatethe compo 60 pipe 25 to a converter 26. The converter con
nents, rather than the successive removal of each
tains a catalyst of an appropriate type at a tem
component in the order of its volatility, as de
perature oi 300° to 350° C. Part of the ethanol
scribed above.
and acetaldehyde are converted to butadiene in
The process of this invention represents an in
the converter, and the e?iuent vapors pass
tegrated process for making butadiene from eth
through a pipe 21 to the heat exchanger 24 which
anol, in which the acetaldehyde formed by de
preheats
the reactants. The vapors leave the
hydrogenationof ethanol is not passed directly
heat exchanger through a pipe 28, and pass to
into the butadiene converter, but, instead, is ?rst
a condenser 29, where more than half of’ both the
passed to a recovery distillation system which
butadiene and the acetaldehyde, and almost all
produces acetaldehyde, largely freed from impuri
the ethanol, are condensed. The vapors and
ties formed in both reactions, for passage to the
condensate pass through pipe 9 to a settling tank
butadiene converter, and recovers unreacted eth
30, where the condensate is drawn o?'through
anol. This process possesses the advantage over
pipes 3| and 32 to distillation column 5| to re
a process in which the products from the acetal
cover the butadiene. The vapors from the set
dehyde converter are fed directly into the buta
diene converter, in that the acetaldehyde con
ul
s
tling tank 30'contain acetaldehyde, butadiene in
5.
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anamount or about 20%‘,diethy1 ether... ethanol.
proximately 1.0%. acetaldehyde. 5%‘ .diethylether,
and mono-ole?nes and saturated hydrocarbon
gaseseimtheaamount' or. about 1.0 %,. and. they pass
55% ~ethanol,.l5.% Water, 10% butadiene and‘a5%
of.‘ other hydrocarbons and. impurities is passed
through‘ pump 41 and is'introduced. through pipe
through a pipe-.33 toacompressor‘ 34 where they
are .compressedito about 55p: s. i-..
The-compressed vapors» and gasespass. through a pipe'S‘SY-toa‘condenser'36, where they are cooled.
to; a temperature; of. about; 238-“ C. Part of the
vapors:condensev under theseconditions and the
condensate and unicon-denscdv vapors and. gases, 10
are introduced under pressure through pipe 31
to the-base ofascrubbing tower 38, having about ‘
4n. ‘trays- The?rst. condensate from the acetalde
hy'sleaproducing; reaction: is: withdrawn from. ‘tank
l‘lrxthrousha pipe-3.9 and-pumped by a. pump-4.11.
through ‘a pipe: ill]; to the top :of; tower 3:8,. This
condensate ‘may-contain‘ about. 8 parts. of. acet'g
Miv under .apressureof 55 to 70 p. s. i. to ahea-t
exchanger 4.9, where. it is; heated to about 1-109 0.
by-meansrof' a suitable. heating ?uid. The feed
passes througha .pipe: ‘50- to a distillation column
5|. at about thefthirtiethtray' thereof. This col
umnmay' be ofthe. ordinary bubble-cap type with
coppertrays; A ?fty-?ve’ traycolumn possesses
sui?cient trays for the: separation desired with
adequate»allowan'ceior plate. ef?ciency. The col
umnisxheated .lby‘ steam, preferably by means -of:.a
ealandria through which thecontents of the kettle
circulate.
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‘When: the: column‘: .operates under a pressure oi’v
aldehyde-,Twparts of‘ ethanol, 13 parts of" water
about 6.5 p.. s. i., the- overhead; :vaporfdistills at
and .2. parts-of acetic acid... This mixture of
about 472°C. :and contains approximately 5.0%
ethanol and acetaldehyde is a strong solvent for 20 acetaldehyda; 90% butadiene and. 5.0% butenes
butadiene even in the presence of a small amount
of: watenand 'it'is; capable-of: scrubbing completely
‘and butane. A smallamount of water may also
be. present in the overhead‘ vapor. Part of the
therbutadiene from the ascending vapors'w-hen .
overhead‘ ‘vapor’ which is removed through pipe
employed‘ in. amounts about equal to, or even
52 is condensed‘in a. condenser 53, the condensate
somewhat lessithanythat. of the'vapors and con 25 being pumped through. a pipe? 54- as re?ux: to: the
densatetentering the baserof the scrubbing. tower
at~._-the temperature and‘ pressure specified. - The
liquid e?iuent. from the base. of thetower contains
column. The reflux ratio. employed’ inv the: opera
tion ofythe column’ may be varied from about
4:1 ‘to 20:1.
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substantially all the'butadiene. originally present
‘The residue. is removed from the kettle '55
in-the entering-gases and: it is-withdrawn through 30 through a pipe 56 audit contains acetal'clehyde,
pipe 3.2v to distillationcolumni'l for recovery of
di'ethyl ether,. ethanol, water andimpurities. It
the butadiene.
.
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is tube noted1 that thescolumn operates with both
'li'hegasesv leaving. the top of tower 3.8 are .ap
an: enriching. and. exhausting section, and that
proximately saturated. with. the. components of
the residue is denuded: of. buta'diene. The residue
the. scrubbing liquid,- principally, acetaldehyde
passes tothe :recoverydistillation' system through
andethanoLand it .iseconomicalto recover these
materials. ‘To-effecttherecovery of the acetalde
hydeandethanol, the. gases are. passed through a
pipe-.42 to a .second scrubbing tower .43, where
they are subjected to the washing action of. a
pipe'2'3.
. condensed. and returned- as: re?ux passes through
a valve ‘5''!’ ‘and through pipe '58, and enters a
scrubber 59 through a pressure reducing valve 60.
The scrubber maybe a forty-tray'column which
operates at .a pressure. of 35 pounds per square
inch'ata-temperatureof 35° C... and it is designed
to remove ‘the acetaldehyde. from the butadiene
down ?owing, stream. of water. The liquid. e?iux
from the tower passes through pipe 44 to pipe 273,
and. thence tothe recovery distillation system.
The gases. from this scrubbing tower, containing
mono-ole?nes, such .as ethylene and propylene,
saturated .hydrocarbon gases, ‘and some carbon
vapor by dissolving the acetalde-hyde- in water.
dioxide. and carbon monoxide are. discharged from I
the system. 'The process‘ just described is the
subject to the copending application Serial No.
I
0f the overhead ‘vapor, the part which is: not
Butacliene is. agasv at this ‘temperature and pres
sureandit' does not. appreciably condense, where
asy’at thesamelt‘ime, acetaldehyde is'readily ab
sorbed in water. ‘.Thewater, introduced at the
501,610 of I. L. Murray, J. 'L. Marsh and S. P. 50 top of the vcolwnns?ows .downward and selectively
Smith, Jr., entitled “Process for making buta
dissolves the acetaldehyde from the ascending
diene."
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' vapors. The'vapors-irom the top of'thIe vcolumn
However,_ it is not essential to practice the
mayicontain ab out 951%" butadiene. and~ 5% butenes
.and' butane. The bntadiene may be separated
the bene?ts of the present invention. The con 65 from‘ the butenes' and they butane by known
densate from the tank l1 may be withdrawn
.method's,;which are nota :part of. the present in
through by-pass pipe 45 to pipe 23, and be carried
vention.
directly to the distillation system. The scrubbing
V’I'he aqueous scrubbing liquid from the bottom
‘liquid employed in column 3.8 may then comprise
fof'the scrubbing tower contains a. small amount
part or‘ all'oi the make-up ethanol required‘ in the
ofacetaldehyde; and it passes through a pipe 6|
process, which maybe introduced‘ through pipe
to: the‘ recovery distillation system.
46, from ethanol storage tank 41. This make-up
‘The scrubber residues from scrubbers 22, 43,
ethanol passes to the column for the recovery of
and“, and the residue from column 5| are com
butadiene and eventually to the recovery disti1la~
iming‘l'ed: in pipe .23- to ‘form a composition con
tion system ‘without additional equipment being
taining approximately‘ 1.5% acetaldehyde, 5.%-di
provided. However, the heat economy secured
ethyl.‘ ether, 40% ethanol, and 35% Water and
‘by feeding the make-up ethanol as part of the
5% vIcy-products. This mixture is introduced
re?ux required in the operation of the ethanol
‘through- a- preheaters?zibymeans of‘pipe 63 to ' a
still would be lost. Alternatively, ‘a separate cycle
distillation column 61. This column may operate
for scrubbing such butadiene-containing ‘gases 70 at'a pressure-of about 40 p. s. i. gauge'and at a
may be provided in which the solvent employed
head temperature-"of about 5'7” to 58°C. It is
as scrubbing liquid isseparately distilled‘ to strip
heated ‘by steam‘, preferably by circulating the
‘process of that application‘in order to secure
0d‘ the ‘butadiene; and residue cooled and. re
used in thescrubbingoperation.
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A- composite feed from'pipe 32 containing ap
contentsv of‘ the kettle‘ through an external in
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clined ca-landria. Amixture. of the. azeotrope of
75 acetail'dehyde ‘and .diethyl ether, together with
2,403,742.
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azeotropes
of
acetaldehyde
and
other
and employed
by
products, the composition being about ‘75% acet
aldehyde, 20% diethyl ether, and 5% by-products,
changer
62;
as ~ heating ?uid in heat ver:
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The addition of make-up ethanol as part of the
re?ux-required‘ in the column used for distilla
tion of the alcohol provides a saving in the heat
otherwise required to operatethe still, as de
scribed in I. L. Murray Patent No. 2,249,847.
Obviously, however, the make-up ethanol may be
is withdrawn as vapor through pipe 65, and
passes as one of the reactants to the butadiene
converter 26. Suf?cient overhead Vapor to con
stitute a re?ux ratio of about 3 to 1 is withdrawn
through proportioning valve 66 through a pipe 61
added in other ways to the cyclic process, as pre
to- a condenser 68, where it is condensed and re
turned as re?ux to the column 64 through pipe 69. 10 viously pointed out. Modifications of the inven
tion other than as speci?cally described‘, may be
a The residues from column 64, containing prin
made without departing from the principle of
cipally ethanol and water, the remainder being
the invention. The essential features of the in
diethyl ether, acetaldehyde and other by-products
vention consist of a cyclic two-step process 'for
pass through a pipe 16 to distillation column ‘H,
the production of butadiene from ethanol, them-'
15
after passing through a pressure reducing valve
tegration of an acetaldehyde-producing reaction
12. This column may operate at a pressure of
with a butadiene producing reaction, and the
20 p. s. i. gauge and a head temperature of 65°‘ to
provision of a common distillation system for re-‘
75° C. It generates an overhead vapor containing
covering the‘ unconverted products of the two
aldehyde, methyl ethyl ketone, and other im 20 reactions.
We claim:; I
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purities. This overhead vapor all passes through
1. A cyclic process for making butadiene which
pipe ‘I3 to condenser 14, where about 116 of the
comprises introducing ethanol vapors to a reac
condensate is withdrawn through pipe 15 to
tion zone, converting a part of such ethanol va
storage. These by-products may be distilled
from time to time to recover their valuable com 25 pors to acetaldehyde’ and separating an acetale
dehyde-ethanol condensate from the remainder
ponents. The remainder of the condensate passes
of the reaction products; concurrently introduc
through pipe 16 to column 1| as re?ux. The
ing ethanol and acetaldehyde vapors to a sepa
column is heated by steam, preferably by circu
acetaldehyde, diethyl ether, ethyl acetate, butyr
lating the contents of the kettle through an ex
ternal inclined calandria.
rate reaction zone, converting a part of the
temperature is su?iciently high, about 120° C.,
ethanol and acetaldehyde to butadiene and sepa
rating‘the butadiene from unconverted ethanol
and acetaldehyde; distilling acetaldehyde from a
mixture containing such unconverted acetalde
hyde and said condensate and passing it to the
to volatilize all the acetaldehyde from the base of
butadiene-producing reaction zone; distilling eth
the column.
anol from a mixture of the remainder of said con
densate and such unconvertedethanol and re
30
In‘ the operation of the acetaldehyde still 64,
there is a tendency for by-products to accumulate
in the upper third of the column, when the base
Such icy-products eventually pass
fromv the top of the column and reduce the con
centration of acetaldehyde below the desired
turning said recovered ethanol to at least one of
value. This may be prevented by withdrawing
the reactionzones; and introducing additional
.40
about 2 to 5% of the total down-?ow from the
ethanol to at least one reaction zone. _
column 64, through pipe 11, either in the liquid
2. A cylic process for making butadiene which
or vapor phase, and introducing it in the upper
comprises introducing ethanol vapors to a reac
third of the by-products distillation column ‘H.
The approximate composition of the side stream
thus withdrawn may be acetaldehyde, 40%, di
tion zone, converting a part of such vapors to
acetaldehyde and separating an acetaldehyde
ethanol condensate from .the remainder of the
ethyl ether, 45%, and .by-products, 15%. This
process is more fully described in application
Serial No. 526,792, ?led March 16, 1944, by M. E.
Hitchcock and J. A. Field, which is assigned to
the same assignee as the present application.
The residue from column ‘H , containing mostly
ethanol and‘water, along with some by-products,
‘is pumped through pipe 18 to distillation column
19 in which ethanol is separated from the water.
This column may operate at a pressure of 50 r
p. s. i. gauge and a head temperature of 118° C.
It generates an azeotropic mixture of 85%
ethanol, 10% water and 5% by-products, which is
withdrawn through pipe 80 as reactant material
for the acetaldehyde and butadiene converters.
The feed to the butadiene converter is withdrawn
through pipe 85. About twice as much vapor as
is withdrawn through pipe 80 is withdrawn
through pipe BI and condensed in condenser 82.
The condensate passes to a re?ux storage tank 83
.to which is added an amount of ethanol equiva
lent to that consumed in the process. This mix
ture is pumped through pipe 84 as re?ux for the
column 19. The column is heated by steam,
preferably by the direct introduction of steam
into the kettle. The aqueous waste is withdrawn
from the kettle through a line 84, and before
being discarded, it is used as a heating ?uid in
the various preheaters shown in the system, for
instance, it may be withdrawn through pipe 86 r
reaction products; concurrently introducing ethé
anol and acetaldehyde vapors to a separate reac
tion zone, converting a part of the ethanol and
acetaldehyde in the vapor phase to butadiene and
separating the butadienefrom unconverted eth
anol and acetaldehyde; distilling acetaldehyde
vapors ‘from a‘mixturecontaining suchuncon
verted acetaldehyde andv said condensate and
passing such vapors to the butadiene-producing
reaction zone; distilling ethanol vapors from a
mixture containing. such unconverted ethanol and
the remainder of said condensate, after expulsion
of acetaldehyde, and returning such ethanol va
pors to both reaction zones; and introducing
make-up ethanol as a reactant to at least one
reaction zone.
3. A cyclic process for making butadiene which
comprises introducing ethanol vapors to a reac
tion zone, converting a part of such vapors to
‘acetaldehyde and separating, an acetaldehyde
ethanol condensate from the remainder of the
reaction products; concurrently introducing eth
anol and acetaldehyde vapors to a separate re
action zone, coverting a part of the ethanol and
acetaldehyde in the vapor phase to butadiene
and separating the butadiene from unconverted
ethanol and acetaldehyde; combining such un
converted ethanol and acetaldehyde with said
condensate to form a mixture containingv acetal
' 2,403,742
,
9
,
~
.
dehyde and ethanol; distilling acetaldehyde va
phasev reactions, distilling acetaldehyde vapors
pors from said'mixture and passing such vapors
from said mixture and introducing them to the
to the butadiene-producing reaction zone; , dis
butadiene-producing reaction zone; distilling at
tilling ethanol vapors from the residue remain
least part of the by-products from the residue
ing from this distillation and returning such eth
anol vapors to, at least one of the reaction zones,
from the acetaldehyde distillation; distilling eth
anol vapors from the residue. of vthe lay-products
distillation and returning such recovered ethanol
to both of said vapor phase reactions, and intro
ducing make-up ‘ethanol as re?ux in said third
and introducing make-up ethanol as a' reactant
to at least one reaction zone.
7
4. Acyclic process for making butadiene which
comprises introducing ethanol vapors to a reac 10
tion zone, converting a part of such ethanol to
‘distillation. ‘
'7. A cyclic process for making butadiene, which
acetaldehyde and separating an acetaldehyde
comprises introducing ethanol‘ vapors to a, reac
tion zone, converting a part of such ethanol to
ethanol condensate from the remainder of the
reaction products; concurrently introducing eth
acetaldehyde and separating an acetaldehyde
anol and acetaldehyde vapors to a separate re
action zone, converting ethanol and acetaldehyde
to butadiene and by-products and separating
15 ethanol condensate from the remainder of the
reaction products; converting a, part of ethanol
and acetaldehyde vapors to butadiene and other
hydrocarbon gases in a separate reaction zone,
butadiene from the by-products formed and un
converted ethanol and acetaldehyde; separating
vat least part of such by-products from uncon
verted acetaldehyde and ethanol; distilling acet
condensing the reaction products, and separating
20 a gaseous hydrocarbon mixture containing buta
diene from unconverted acetaldehyde and etha
aldehyde vapors from a mixture containing such
nol; bringing such hydrocarbon gases in intimate
contact with a scrubbing liquid containing etha
unconverted acetaldehyde and, said condensate
and introducing them to the butadiene-producing
nol as the principal constituent to liquefy and
reaction Zone; distilling ethanol vapors from a
mixture containing such unconverted ethanol and
the remainder of .said condensate, after expulsion
of acetaldehyde, and returning such recovered
dissolve butadiene therein; distilling butadiene
from such scrubbing liquid and. recovering a
scrubbing liquid residue; distilling acetalde
hyde vapors from a mixture containing such un
ethanol to at least one reaction zone; and intro
converted acetaldehyde and said condensate, and
ducing make-up ethanol to at least one reaction 30 passing such vapors to the butadiene reaction
zone.
zone; distilling ethanol vapors from a mixture
5. A cyclic process for making butadiene which
containing said scrubbing liquid residue, said un
comp-rises introducing ethanol vapors to a reac
converted ethanol, and the remainder of said
tion zone, converting a part of such ethanol to
acetaldehyde and separating an acetaldehyde
ethanol condensate from the remainder of the
condensate, after expulsion of acetaldehyde, and
35 returning such ethanol vapors to both reaction
zones; and introducing make-up ethanol to at
reaction products; concurrently introducing eth
least one reaction zone.
anol and acetaldehyde vapors to a separate re
action zone, converting ethanol and acetaldehyde
to butadiene and separating butadiene from un
converted ethanol and acetaldehyde; combining
.8. A cyclic ‘process for making butadiene, which
comprises introducing ethanol vapors to a reac
40 tion zone, converting a part of such ethanol to
acetaldehyde and separating an acetaldehyde
ethanol condensate from the remainder of the
reaction products; converting a part of ethanol
such unconverted ethanol and acetaldehyde with
said condensate to form, a mixture containing
acetaldehyde, ethanol‘and by-products of the two
vapor phase reactions, distilling acetaldehyde
vapors from said mixture and introducing them
to the butadiene-producing reaction zone; dis
tilling at least part of the Icy-products from the
residue from the acetaldehyde distillation; dis
tilling ethanol vapors from the residue of the by 50
products distillation and returning such recovered
ethanol to at least one of said reaction zones; and
introducing make-up ethanol to at least one re
action zone.
and acetaldehyde vapors to butadiene and other
hydrocarbon gases in a separate reaction zone,
condensing the reaction products, and separating
a, gaseous hydrocarbon mixture containing buta
diene from unconverted acetaldehyde and eth
anol; bringing such hydrocarbon gases in inti
mate contact with a scrubbing liquid containing
ethanol as the principal constituent to liquefy and
vdissolve butadiene therein; distilling butadiene
from such scrubbing liquid and recovering a
'
scrubbing liquid residue; distilling acetaldehyde
6. A cyclic process for making butadiene which 55 vaporsfrom a mixture containing such uncon
verted acetaldehyde and‘said condensate, and
passing such vapors to the butadiene‘ reaction
comprises introducing ethanol vapors to a reac
tion zone, dehydrogenating a vpart of such etha
. nol to acetaldehyde and separating an acetalde—
hyde-ethanol condensate from the hydrogen gas
~ ‘zone; distilling ethanol vapors from a mixture
containing vsaid scrubbing liquid residue, said un
produced; concurrently introducing ethanol and
converted ethanol, and the remainder of said con
acetaldehyde vapors to a separate reaction zone, 60 densate, after expulsion of acetaldehyde, and re
converting ethanolv and acetaldehyde to butadiene
and separating butadiene from unconverted eth
anol and acetaldehyde, combining such uncon
verted ethanol and acetaldehyde with said con
densate to form a mixture containing acetalde
hyde, ethanol and by-productsof the two vapor
turning such ethanol vapors to both reaction
zones; and introducing make-up ethanol as said
scrubbing liquid.
65
'
'
IRVIN L. MURRAY.
JAY L. MARSH.
SILAS P. SMITH, JR.
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