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Патент USA US2407827

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Sephl‘i', £946.
. F. ‘E. FREY ET AL
'2, ‘21,825
PRODUCING AND CONCENTRATING DIOLEFINS
Original‘ Filed April 1, 194'].
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INVENTOR
FREDERICK E.FREY
BY ROBERT D smw
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Patented Sept. 17, 1946
2,407,825
UNITED STATES PATENT OFFICE
2,407,825
PRODUCING AND CONCENTRATING
DIOLEFIN S
Frederick E. Frey, Bartlesville, 0kla., and Robert
D. Snow, Edgewood, Md., assignors to Phillips
Petroleum Company, a corporation of Delaware
*
Original application April 1, 1941, Serial No.
386,324. Divided and this application August
23, 1943, Serial No. 500,408
16 Claims.
1
(Cl. 260-r-329)
2
t
This invention relates to processes for obtain
ing conjugated diole?ns in a concentrated form
from hydrocarbon mixtures. It relates further
to the concentration of low boiling diole?ns, more
pound was a polymeric sulfone.
He disclosed a
process for the preparation of the crystalline
monomeric sulfone in which the reaction of the
diole?n with S02 was carried out at room tem
particularly cyclopentadiene, butadiene, and its 5 perature in the presence of anti-catalysts such
lower boiling homologues, from mixtures contain
as polyhydric phenols which inhibited the for
ing other hydrocarbons of closely adjacent boil
mation of the polysulfone.
ing points. As one modi?cation, it relates to the‘
Perkins (Canadian Patent 329,043 (1933) and
production of a mixture of substantially normal
U. S. 1,993,681 (1935)), disclosed a process for
C4 hydrocarbons by the dehydrogenation of nor 10 separating diole?ns from hydrocarbon mixtures
mal butane and/or normal butenes and the sepa
by heating the mixture with less than half its
ration of a butadiene concentrate therefrom.
weight of sulfur dioxide for prolonged periods of
Diole?ns are produced in a number of ways
time at about 100° C. The process described by
which include cracking of heavier oils, pyrolysis
Perkins may be continuous or stepwise with re
of gaseous hydrocarbons other than methane, the 15 spect to the removal of the crystalline addition
copolymerization of acetylene and ethylene to
product and the return of the sulfur dioxide to
form bu'tadiene, catalytic and thermal conver
the reactor, but is de?nitely a batch process with
sion of alcohols, both of the same number of car~
respect to the hydrocarbon mixture treated.
bon atoms per molecule as the desired 'diole?n
We have now found that conjugated diole?ns
and of a fewer number of carbon atoms per mole 20 may be separated from mixtures containing them .
cule, and other more or less involved chemical
by reacting with sulfur dioxide at 60-80" C., with
processes, as well as the dehydrogenation of the
or without materials such as isobutylene, and
corresponding ole?ns which in turn may have
been produced by the dehydrogenation of the
polyhydric phenols which inhibit the formation
of the heteropolymeric sulfone addition product
corresponding paraf?ns. Although this latter
and with or Without catalysts which promote the
formation of the monomeric sulfone, the said
process being continuous with respect to the ?ow
procedure is one of the more direct ways of pro
ducing diole?ns it has not yet found very exten
sive commercial application, and one of the ob
stacles in its commercial development has been
of hydrocarbon and continuous or stepwise with
respect to the separation of the diole?n-SOz ad
the dimculty of effecting separation of ole?ns 30 dition product.
and diolefins from each other and from mixtures
An object of this invention is to concentrate
containing the corresponding parai?ns.
conjugated diole?ns, particularly butadiene, by
Various processes have been proposed for the
separation of conjugated diole?ns by means of
their reactions with sulfur dioxide. Badische'.
separation from other hydrocarbons of similar
boiling temperatures in a continuous manner.
Another object is to produce a butadiene con
Anilin Und Soda-Fabrik, German Pat. 236,386
(1911) disclosed the fact that conjugated diole
ing relatively low concentrations of butadiene
?ns react with gaseous sulfur dioxide or aqueous
such as are produced by cracking or dehydrogen
sulfurous acid at ordinary temperature to give
ation.
mainly
an
insoluble, amorphous compound.‘
centrate from mixtures of hydrocarbons contain- '
.
They stated that when the amount of S02 pres
Another object is to furnish a method by which
a conjugated diole?n product, previously concen
ent was small or the reaction time short, the
trated by some other process, can be further freed
product was partly soluble in water, and the solu
of diluent para?in and ole?n hydrocarbons and
ble part crystallized in needle crystals which de
other undesirable impurities.
composed easily on heating to regenerate the di-. 45 Another object is to separate a mixture of
ole?n and S02. They suggested this reaction as
paraf?n, monoole?n and diole?n hydrocarbons
a means of separating diole?ns.
into three fractions consisting of the respective
Matthews and Strange, U. S. 1,196,259 (1916) ,
classes of hydrocarbons, each in concentrated
disclosed a'process for the puri?cation of diole
form.
?ns by reaction with sulfur dioxide in the pres-1 50 Another object is to combine methods for sepa
ence of halogen-containing compounds which
rating butadiene, butenes and butane from hy
they claimed served to promote the formation of
drccarbo-n mixtures with two-stage catalytic de
the crystalline material. The only temperature
hydrogenation with cycling of the butane and
butenes to the ?rst and second stages, respective
cited was 42° C. They considered this soluble,
crystalline material, which decomposed at 120° C.,‘ 55 1y, of the dehydrogenation process in order to
to be a sulfoxide.
obtain high yields of butadiene from n-butane or
Staudinger, German 506,839 (1930), taught
that the easily decomposed crystalline compound
a
C4 fraction.
/
,
Another object is to increase the concentration
was a monomeric cyclic sulfone formed by 1-4
of butenes in the charge stock going to the sec
addition, and that the insoluble amorphous com 60 0nd stage of a two-stage dehydrogenation proc
2,407,825
3
ess for producing butadiene from normal butane
in order to improve the efficiency of the second
stage.
Further objects will become evident to those
skilled in the art as the description of the process
proceeds.
It has been disclosed in U. S. Patent 2,186,524,
of which we are coinventors, that sulfur dioxide
forms minimum-boiling azeotropic mixtures with
each of the butanes and butenes. In the copend l0
ing application of Frederick E. Frey, Serial No.
4
drawing which shows diagrammatically by way
of a flow sheet an arrangement of apparatus for
practicing our invention together with various
modi?cations thereof. In connection with this
drawing the invention will be described in vari
ous modi?cations for the production of butadi
ene. It will be appreciated that similar proce
dures may be followed to affect a production of
other low boiling diole?ns discussed‘ in this ap
plication.
I
I
,
Referring now to the drawing, a‘normal C4 hy
drocarbon material which contains butadiene, '
383,235, ?led March 13, 1941, it has been dis
and which may be derived from any vsuitable
closed that butadiene may be separated from
source such as a fraction obtained from the gases
accompanying C4 hydrocarbons by a limited
azeotropic distillation in the presence of sulfur 15 resulting from the cracking of heavier oils or in
the cracking of light gases to form normally gas
dioxide, with separation of a kettle product con
eous ole?ns and/or low boiling diole?ns, is
taining butadiene and Z-butenes, and substan
charged through pipe i0 controlled by a valve ll
tially free of sulfur dioxide, the distillation being
to suitable fractionation equipment illustrated
carried out so that there is a minimum of, or no,
chemical reaction between sulfur dioxide and 20 by fractionating column i2. In fractionating
column I2 a distillation of the C4 hydrocarbons
any unsaturated hydrocarbons present. We have
takes place in the presence of sulfur dioxide,
now found that butadiene may be separated from
such a kettle product by a process involving re
' which is added to the system through a pipe I3
and which may be introduced into a 1oWer-por-.
acting the butadiene with sulfur dioxide to form
a monomeric sulfon'e, particularly when this is 25 tion of the fractionating column l2 through valve 7
I4 or which may be introduced entirely or in
done under‘ novel conditions elsewhere herein
part at some suitable point above the point of
more fully discussed. We have further found
introduction of C4 hydrocarbons through pipe
that in our present process the initial distilla
[0 by being passed from pipe {3 through pipe I5
tion in the presence of sulfur dioxide may be ad
vantageously carried out under conditions such 30 controlled by valve IS. The fractionating col
umn l2 contains suitable packing or bubble
that a substantial portion, if not all, of the di
plates, not shown, to aid in fractionation and is
suitably heated at the bottom by heating means
illustrated by heating coil l 1, and suitable and
We have found that temperatures of 60-80’ C. 35 cooling re?ux is obtained at the top by means
such as is illustrated by the cooling coil 18. In
are sufficiently high to effectively suppress the
one modi?cation the fractionation is so conduct
formation of undesirable heteropolymeric sul
ed that substantially all of the unsaturated hy
fones of either the monoolefins or diole?ns nor
drocarbons are concentrated in the lower part,
mally present and yet also suiiiciently high to
give a suitable reaction rate to the formation of 40 and only saturated hydrocarbons are removed in
the overhead stream. Although the fractionat
the desirable monomeric sulfone. However, par
ing column can be operated over a fairly wide
ticularly when operating in the lower part of the
ole?n material present, such as butadiene, is re
acted with sulfur dioxide to form a monomeric
sulfone.
temperature range, which is more favorable to
range of temperature, it has been found conven
the separation of paraffins by azeotropic distilla
ient to operate with a kettle temperature of
tion, we may use inhibitors of the branched chain 45 about 80° C. and a head temperature of about
60° C. The amount of sulfur dioxide added to
ole?n type such as isobutylene or unsym-methyl
ethyl ethylene in amounts corresponding to 2 to
the fractionating column should be at least suf?
10 per cent or more of the total hydrocarbons
cient in quantity to form azeotropic mixtures -
with substantially all the parafiin hydrocarbons
present, or very small proportions of typical anti
oxidant inhibitors of the type of polyhydric phe 50 and to pass from fractionatingcolumn l2 with
them as overhead low boiling fraction. As will
nols, etc., well known to those skilled in the art
be recognized by those skilled in the art the min
to prevent polymeric sulfone formation, and we
imum sulfur dioxide requirement will vary with
may use a catalyst to accelerate monomeric sul
the composition of the hydrocarbon mixture in
fone formation. However, in most cases it is un
troduced to the fractionating column and with
necessary to use catalysts or inhibitors in the
speci?ed temperature range.
In its simplest form the present invention com
prises continuous feeding of a liquid hydrocar
the conditions under which the column is oper
ated. When treating a C4 hydrocarbon mixture,
the amount of sulfur dioxide will generally be
of the order of 2 to 3 mols of sulfur dioxide per
bon mixture with one-half to three times its
weight of liquid sulfur dioxide into a reaction 60 mol of butane plus isobutane, more speci?cally
about 2.5 mols. In many instances we prefer to
chamber maintained at 60-80" 0., said reaction
have a suf?cient excess of sulfur dioxide over
chamber being of such capacity as to allow time
this amount to have an appreciable proportion’
for completion of the reaction, and distilling the
thereof in the kettle product.
'
volatile matter from the stream emerging from
A low boiling fraction comprising sulfur di—.
the reactor at temperatures not exceeding 100°
oxide and butanes is removed from a top portion
C. The sulfone addition product obtained as a
of a fractionating column I2 through pipe 20
residue may thereafter be decomposed by heat
and may be removed from thesystem through
ing to 120-130° C. and S02 can then be extracted
valve 21. In many instances, however, it will '
from the gaseous products by well known meth
ods. This process is suitable for general appli 70 be desirable to subject this material to further
treatment in the system, and for this purpose it .
cation to the lower conjugated diole?ns, espe
is passed from pipe 20 through pipe 22 con
cially butadiene, piperylene, isoprene, dimethyl- A
trolled by valve 23 to separating unit 212. This
butadiene, and cyclopentadiene.
separating unit 24 will comprise suitable equip
Our invention Will now be more speci?cally de
scribed in connection with the accompanying 76 ment for recovering a normal butane stream, a
2,407,825
5
sulfur dioxide stream, and for removing and
discharging from the system other materials
which may be present in the low-boiling mate
rial passing through pipe 2!} which are not de
sired in the system. Such separation equipment
6 .
which may be 100 per cent or more in excess of
that quantity. The reaction chamber 35 is of
sui?cient capacity to allow time for substantially
complete reaction of butadiene with sulfur di
oxide and is preferably maintained at a reaction
temperature in the range of about 60° to 80° C.
by a temperature controlling means not shown.
The reaction chamber may be arranged so that
the kettle product from the column enters at the
in the production of liquid sulfur dioxide; or it
may comprise a refrigerating coil or vessel to cool 10 bottom through pipe 32 as shown with the reac
tion mixture being Withdrawn from the top,
the overhead mixture below a critical solution
through pipe 4% controlled by a valve 41 and
temperature together with a separator from
passed to a flash vaporizer 53. In some instances
which a light liquid layer may be removed to a
it may be found more desirable to have the charge
fractionating column, and also from which a sul
fur dioxide fraction may be recovered. The 15 material enter at the top and the reaction eiiiu
ent withdrawn entirely from the bottom in which
fractionating column can then be so operated
case the material passing through pipe ‘32 is
that a substantially pure paraffin is removed as
passed through pipe 44 controlled by a valve 45
a kettle product and a para?in-sulfur dioxide
leading to the top part of reaction chamber
azeotrope is taken overhead and recycled to the
aforesaid means for cooling and separation of 20 35 and the reaction mixture will then be with
drawn from the bottom of the reaction chamber
liquid layers. In connection with such equip
through pipe 5| controlled by valve 52 leading to
ment the sulfur dioxide layer may if desired
may consist of means for scrubbing the gases
with water and recovery from the water of sul
fur dioxide in a manner similar to that employed
be passed to still another fractionating column,
pipe 46.
The operation of the fractionating column I2
head and also recycled to the said cooling and 25 is such as to permit concentration of butadiene
and sulfur dioxide in the bottom portion and, as
separating means while sulfur dioxide is recov
stated, a reaction between these materials to form
ered in a fairly pure state as a kettle product.
a monomeric sulfone may be effected within this
A sulfur dioxide fraction may be removed from
fractionating column. When this is done the
separating unit 24 through pipe 25 controlled
by a valve 26. A portion of this material may be 30 separation of other materials from the butadiene
is facilitated since the butadiene is being removed
returned directly to the top part of fractionat
as such by chemical reaction, and the sulfone
ing column l2 as re?ux by means not shown
so produced can, therefore, be removed rela
and/or to the fractionating column l2 through
tively free of unreacted butadiene which is main
pipe !3. Undesired light gases may be removed
from separating unit 24 and from the system 35 tained in the lower portion of the fractionating
column and subsequently reacted. When such
through pipe 2i controlled by a valve 23.
operating conditions are followed the material
The kettle product of fractionating column l2
withdrawn through pipe 32 will contain very lit
will consist mainly of butenes, butadiene and/or
tle unreacted butadiene and may be passed there
a monomeric butadiene-sulfone, which latter
may have been formed in the fractionating col 40 from through pipe 3% controlled by a valve 3'!
directly to flash vaporizer 58 for subsequent treat
umn, together with some excess sulfur dioxide.
ment, with elimination from the system of the
If the fractionating column 82 is so operated that
reaction chamber 35.
substantial formation of this butadiene-sulfone
The ?ash vaporizer so is preferably operated
takes place, it may be found desirable to have a
small amount of an inhibitor present to prevent 45 under a low absolute pressure and at a small ele
vated temperature which should be substantially
any substantial formation of heteropolymeric
below the decomposition temperature of the
compounds of high molecular weight. When such
butadiene-sulfone which is in the neighborhood
inhibitors as isobutylene are not present in the
of about 120° C. Unreacted material which will
material charged through pipe ! ll, or are-not pres
ent in sufficient quantities, such inhibiting mate 50 comprise primarily sulfur dioxide and butenes to
gether with possible small amounts of butane are
rial may be added to fractionating column l2
removed from flash vaporizer 55 through pipe 53
through pipe 30 controlled by a valve 3!; other
controlled by a valve 54 which leads to com
inhibiting materials discussed herein may like
pressor 55. This compressor 55 serves to main
wise be added in this manner as and when de
tain a low absolute pressure within the ?ash va
sired. The kettle product is removed from frac
porizer and to remove vapors and gases evolved
tionating column i2 through pipe 32 controlled
therefrom as fast as they ‘are released. These
by valve
and when little or no butadiene-sul
gases and vapors may be discharged from the
tone is contained therein, this material may be ‘
system through pipe 5% controlled by a valve 5'!
passed through valve 34 to a reaction chamber
35 wherein substantially all of the butadiene is 60 or may be passed entirely or in part through pipe
58 controlled by valve 59 to a separating unit 60.
converted to the monomeric sulfone. When suf
This separating unit 60 will also comprise suit
ficient sulfur dioxide is not present in this stream,
able equipment for effecting a separation of the
additional quantities may be added from pipe 13
materials charged thereto into any suitable or
through pipe 4o controlled by a valve 41, which
passes to pipe 32. When a butadiene-containing 65 desirable fractions which will generally comprise
at least a normal butene fraction and a sulfur
material is available which is not unduly diluted
dioxide fraction. together with. any heavy mate
with but-ones or the like, this material may be
rials that may be present. Sulfur dioxide may
added directly to reaction chamber 35 through
be removed through a pipe 6| controlled by a
pipe 42 controlled by a valve (13, the material
being passed through pipes All and 32 to reaction
valve '52, and undesired heavy materials may be
chamber 35, and in some instances such a frac
removed through a pipe 63 controlled by a valve
tion may constitute the sole charge to the process.
64.
The amount of sulfur dioxide added to reaction
The butadienasulfone which will generally be ‘
chamber 35 should be molecularly equivalent to
present as a liquid under the preferred conditions
the unreacted butadiene present plus an excess
discussed above is maintained at a somewhat ele
from which an azeotropic mixture is taken over
2,407,826
8
vated temperature below its decomposition tem
perature by suitable heating means represented
through pipe 9E1. Such a single stage of dehy
drogenation will be similar to that disclosed by
by a heating coil 65 to free it of undesired gaseous
Frederick E. Frey in his ccpending application
material and is then passed through a pipe 96
Serial No. 354,890, ?led August 30, 1940, or his
controlled by valve IS'I to a pump 68 and then 5 hereinbefore mentioned application Serial No.
through a pipe 69 to a heating coil ‘IE! located in a
383,235, ?led March 13, 1941. In many instances,
suitable heat exchanger or furnace ‘II. In the
however, it will be desirable to conduct the de
heating coil ‘lo the butadiene-sulfone is heated to
hydrogenation unit 92 in a manner such as to
a decomposition temperature and maintained at
produce optimum yields of butenes with little if
this temperature which Will generally be in the 10 any production of butadiene, with subsequent de
‘ range of about llil" to 130° 0, preferably about
hydrogenation cf the normal butenes to buta
120° C., for a period of time su?‘lcient to e?ect
diene in a second dehydrogenation step. When
substantially complete decomposition, but for a
this is the case a C4 fraction may be passed from
time so limited that only a minimum of second
pipe I82 through pipe Ho controlled by valve III
ary reactions take place. The products of this
to a second dehydrogenation unit I I2 operated so
‘decomposition are passed from heating coil ‘l8
as to produce from butenes charged thereto opti
through a pipe "I2 controlled by a valve ‘I3 to
mum yields of butadiene. The dehydrogenation
suitable separating means ‘If: illustrated by the
eilluent is passed from unit I it through a pipe
scrubber shown. Sulfur dioxide is separated
i l3 controlled by a valve I If; to a suitable separa
from butadiene by suitable means as by Wash
tor I I5. Hydrogen and other material lighter
ing the gases with water introduced through pipe
than 04 hydrocarbons are removed through pipe
l6 controlled by valve '5? to a spray nozzle "it. A
55% controlled by valve iii‘. A C4 fraction con
sulfur dioxide solution is removed from the lower
taining a substantial amount of butadiene is re
part of the scrubber '55 through a pipe
con
trolled by a valve 8i and butadiene in a relatively
moved through pipe H8 and may be discharged 7
pure state is removed as a gas through a pipe 82
this material may be introduced directly to re
controlled by a Valve t3 and may be passed to
suitable storage or further puri?cation equip
ment as may be desired. Any undecomposed
action chamber 35 through pipe 52. This mix
ture may be treated in fractionating column I2
by being passed from N8 through pipe I28 con
butadiene-sulfone present in the material passing
trolled by valve I2! to pipes 565 and It and frac
through pipe l2 may be removed from the sepa
from the system through valve IIi'l.
If desired
rating means ‘i5 and reintroduced to pipe 659 by
means not shown.
tionating column I2 for treatment as has been
discussed. Material higher boiling than C4 by
drocarbons may be removed from separating
While this part of our invention may be oper
myeans M5 through a pipe I22 controlled by valve
ated as described for the puri?cation of buta- '
diene obtained from any suitable source, this sep
aration treatment is advantageously combined
with one or more dehydrogenation steps for the
production of butadiene from normal butane
and/ or from normal butenes and such a coopera
tive combination of process steps is to be consid
ered a part of our invention.
A normal butane
fraction obtained from the material passing from
the fractionating column I2 is removed from sep
arating unit 24 through a pipe 913 controlled by
a valve iii and passed to a dehydrogenation unit
82. This material may be joined by normal bu
tane secured from any suitable source and intro
duced to the system through pipe 93 controlled
by a valve 9%, and at times normal butane may
be so introduced to our process as the sole
51.3.
As has been discussed the kettle product of
fractionating column I2 will contain substantial
amounts of normal butenes which will ?nd their
way to separating unit 69. These normal butenes
may be recovered by means of separating unit 63
in a more or less concentrated form and maybe
passed therefrom through pipe I24 controlled by
a valve I25 directly to the pipe III! and the de
hydrogenation unit H2. In some instances it
may be desirable to have the normal butenes pro
duced by the dehydrogenation unit 92 in a more
concentrated condition before they are charged
to the dehydrogenation unit I I2. When this is
the case the C4 fraction passing through pipe
H32 may be removed through pipe I30 controlled
by a valve MI and passed to suitable ole?n con
centration means represented by a fractional dis
tillation column I 32. Ole?ns may be separated
to separating means 9? which may be of a simple
from the para?ins in a more concentrated form
type to separate C3 and lighter material from C4 55 in fractional distillation column I32 by distilla
hydrocarbons.’ Hydrogen and other material
tion in the presence of sulfur dioxide in a man
lighter than C"; hydrocarbons are removed from
ner disclosed in the previously mentioned Patent
separator 81 through a pipe I to controlled by a
2,186,524, Sulfur dioxide forethis purpose may
valve til 5. C4 hydrocarbons are removed through
be introduced through a pipe I33 controlled by a
pipe 582. If any material heavier than C4 hydro~ 60 valve I 34. The fractionation may be ‘aided by
carbons is present in the e?luent of the dehy
suitable packing or the like not shown, by heating
drogenation, this may be removed through pipe
means represented by heating coil I35, and by
m3 controlled by a valve m4, but in many in
cooling and re?ux means illustrated by cooling
stances such a removal of heavier material will
means I36. A para?in-containing mixture is re
not be necessary. When the dehydrogenation 65 moved as a low boiling fraction through pipe I3‘!
in unit 92 is such that substantial amounts of
and may be discharged from the system through
butadiene are present in the effluent, the C4 frac
a valve I38 or may be passed entirely or in part
tion may be passed through pipe Hi2 and, valve
from pipe I 31 through pipe Iél) controlled by a
I05 to pipe Ills and through valve It)? to pipe I9
valve “II to pipe 22 and separating unit 24. A
and fractionating column I2 for treatment as 70 higher boiling, ole?n-containing fraction, which
has been discussed. When this modi?cation is
may or may not contain sulfur dioxide, is re-=
followed it may be desirable to operate fraction
moved from fractionating column I32 through a
ating column I2 so that a substantial portion of
pipe I42 and may be discharged through a valve
the butenes is contained in the material passing
I43 or may be passed, as Will generally be the
through pipe as and in the material passed 75 case, from pipe I42 through pipe I 44 controlled
charge. The eflluent of the dehydrogenation is
passed through a pipe 95 controlled by a valve 96
2,407,825
9
10
by'a valve I45. If this material is suitably free
tuted, the operation of reaction chamber 35 and
immediately subsequent equipment remaining as
of- sulfur dioxide, it may be passed on through
pipe Mil and valve I46 directly to pipes I24 and
described.
' I I0 and dehydrogenation unit I I2. In most cases,
Example I
however, this material will contain an appreciable
amount of sulfur dioxide, in which case it may be
As an example of one method of practicing our
passed from pipe III-I through pipe Ill'I controlled
I invention, a normal butane fraction separated ‘
by a valve I48 to pipe 58 and separating unit 60.
taining appreciable amounts of normal butenes
may be introduced to the system through pipe
I50 controlled by a valve I5I and leading to pipe
from natural gas is dehydrogenated in dehydro
genation unit 92, in admixture with a recycle
normal butane fraction, at a low superatmos
pheric pressure and a temperature of about 1050“
F. in the presence of a mass of granular dehy
I24. When such a fraction contains substantial
amounts of normal butane or the like which
bauxite with chromium oxide, the flow rate be
In some instances a hydrocarbon fraction con
drogenation catalyst prepared by impregnating
should be removed, the material may be passed
from pipe I50 through pipe I52 controlled by a
valve I53 leading to pipe I30 and ole?n concen
trating means I32.
ing maintained between about 1 and 2 liquid vol- ‘
umes of butane per volume of catalyst per hour.
The e?iuent, which contains a substantial quan
tity of butenes and a small amount of butadiene,
is cooled and condensed to recover a C4 fraction,
In some instances such a
material may constitute the sole source of charge
to our process.
20
The dehydrogenation unit 92 and the dehy
drogenation unit I I2 will be comprised of suitable
which is passed from separating unit 9'! to the
fractionating column I2, wherein distillation
takes place in the presence of added sulfur diox
ide. A butane-sulfur dioxide fraction is removed
as a low-boiling fraction and passed to separating
unit 218, in which a. normal butane fraction is
recovered and passed to dehydrogenation unit 92
as the recycle normal butane fraction. A high
heating units or furnaces, catalyst chambers, and
the like, known to the art for effecting and main
taining catalytic, substantially nondestructive de
hydrogenation of low, boiling hydrocarbons.
While it may be found possible to effect one or
both of the dehydrogenations in the absence of a
boiling, butenes-containing fraction is removed
catalyst, we prefer to employ catalytic dehy
from fractionating column I2, and a normal bu
drogen-ation for most of the charge stocks which 30 tene fraction is recovered therefrom by employ
ing reaction chamber 35, ?ash vaporizer 50, and
separating unit 60. This normal butene fraction
is dehydrogenated in dehydrogenation unit II 2
will be introduced to our process, using any suit
able dehydrogenation catalyst or catalysts. As is
known, the catalyst chambers may be so arranged
that heat is supplied to the catalyst body or bodies
and to the reacting mixture to keep the reaction
in the presence of a granular catalyst which con
sists of bauxite treated with an alkali which
leaves an alkaline residue, the dehydrogenation
temperature being about 1200° F. Methane is
added to maintain a total pressure slightly above
atmospheric and an initial partial pressure of
normal butenes of about 3 pounds per square inch
absolute, and the flow rate is about 1.5 liquid vol
ume of butenes per volume of catalyst per hour.
By means of separating unit II5 a C4 fraction,
containing between 15 and 20 per cent butadiene,
is separated from the dehydrogenation e?luent
and also passed to the fractionating column I2.
at a desired level. Stationary masses of granu
lar catalysts may be used, or ?owing masses of
?nely powdered solid catalysts may be employed,
or other modi?cations of catalytic dehydrogena
tion may be employed as will be found most suit
able. While the various fractional distillation
units have been shown as single fractional dis
tillation columns it is to be understood that this
, is merely diagrammatic and any of them may
comprise two or more fractional distillation col
umns accompanied by conventional supplemen
tary equipment as will be readily understood by
The high-boiling, butenes-containing fraction
removed from fractionating column I2 also con
tains the butadiene produced by the process.
50 This fraction is passed through reaction cham
ber 35 at a temperature of about 70° C. in the
equipment,v and the like, may be included and
presence of an excess of sulfur dioxide, the time
supplied by one skilled in the art in connection
being such that substantially complete conver
with any speci?c modi?cation or installation in
sion of the butadiene to the monomeric buta
the light of the detailed discussions of material
?ows, reaction conditions, fractions desired, and 4 diene-sulfone is effected. The e?iuent is passed
to the flash vaporizer 50, which is maintained at
material streams to be separated which are dis
about 100° C. and a subatmospheric pressure.
closed and discussed herein. Isobutane, and/or ‘
Vaporous material is removed by compressor 55
isobutene may be found to be present in one or
to separating unit 60, a normal butene fraction
more of the C4 fractions being treated, or may
be introduced purposely through pipe 30, as dis- " being recovered therefrom for subsequent treat
ment as has been described. The residual buta
cussed. Such iso C4 hydrocarbons can be re
one skilled in the art. Additional pumps, heat
ers, coolers, meters, ?ow controllers, temperature
indicating and controlling equipment, re?ux
moved through pipes 21, I00, H6, 6|, and/or 53,
diene-sulfone is removed as a liquid from ?ash
as will be appreciated.
Other low-boiling diolefins can also be pro
vaporizer 50 by pump 68, and is heated in coil 70
to about 120° C. to effect decomposition of the
‘butadiene-sulfone, and butadiene is recovered in
a substantially pure state through pipe 82‘as a
product of the process.
duced by our process, especially isoprene and
cyclopentadiene. Piperylene is generally more
readily separated from accompanying hydrocar
bons, and its production will not require such
elaborate treatment in most cases.
Example II
While sul
fur dioxide will react with C5 diole?ns to produce 70
a diole?n-sulfone, it is not so well suited for use
in connection with separating means I2 or I32.
Therefore, when treating C5 hydrocarbons to pro
duce C5 diole?ns, other saturate—unsaturate sep
aration steps known to the art should be substi
As a modi?cation of the practice of the inven
tion as in Example I, the dehydrogenation of
normal butane is carried out at a temperature of
about 950° F. in the presence of a granular chro
mium oxide gel, which contains about an equi
75 molar amount of alumina and is prepared in the
2,4073% ‘
11
12
manner disclosed in U. s. Patent 2,093,959, the
dehydrogenation e?iuent containing practically
temperature of said zone between 68° and 80° C‘.,
maintaining said hydrocarbon mixture and sulfur
dioxide in liquid phase in said zone by the main
tenance of elevated pressure in said zone, react
ing substantially all free dicle?n with sulfur di
no butadiene. The C4 fraction from the effluent
of dehydrogenation unit H2, operated as in Ex
ample I, is not passed to fractionating column 52,
but is removed through pipe M8 and valve H9,
oxide in said zone to form the monosulfone, pre
venting formation of heteropolymeric reaction
products of said diole?n and sulfur dioxide by
and introduced directly into reaction chamber 35
through pipes 62 and lid, along with the high‘
continuously maintaining in said zone a branched
boiling fraction from column 52 and an excess
of sulfur dioxide passed through pipe as and valve
ti.
‘ chain monoole?n having the same number of car
The e?luent of the reaction chamber 35 is
bon atoms per molecule as said diolefin in an
amount corresponding to from 2 to 10' per cent
of the total hydrocarbons present‘ as the sole sup
passed through pipe 5! to ?ash vaporizer 5E), and
the remainder of the operation is as given in Ex
ample, I.
pressor of such heteropolymeric reaction prod
ucts; continuously removing the reacted mixture
Example III
As an example of another method of practicing
from said zone, and resolving the withdrawn re
action mixture into the sulfone and unreacted
our invention, a normal butane fraction is de
hydrogenated in dehydrogenation unit 912 at a
pressure of about 10 pounds per square inch gauge
materials.
2. The continuous process of separating butadi
one from admixture with other close-boiling more
and a temperature of about 956° R, in the pres
ence of a mass of granular chromium oxide gel,
saturated hydrocarbons which comprises continu
ously feeding said butadiene-containing hydro~
the ?ow rate being about two volumes of liquid
butane per volume of catalyst per hour.
carbon mixture and from one-half to three times
its Weight of sulfur dioxide into a reaction zone,
the amount of said sulfur dioxide being in excess
of that molecularly equivalent to the diole?n pres
The re
sulting C4 fraction from separator 91 is passed
to ole?n concentration unit I32. A normal bu
tane fraction is separated and returned to dehy
drogenation unit 32, and a normal butene frac
ent in said mixture, maintaining the'temperature ‘
of said zone between 60° and 80° C., maintain
tion, containing some normal butane, is Sepa
rated and passed to dehydrogenation unit H2,
ing saidv hydrocarbon mixture and sulfur dioxide
in liquid phase in said zone by the maintenance
wherein catalytic dehydrogenation takes place to '
produce butadiene.
..
of elevated‘ pressure in said zone, reacting, sub
The resulting C4 fraction is
stantially all free butadiene with sulfur dioxide
passed from separator H5 to fractionating col
umn i2. Sulfur dioxide is added through valve
Iii, and a small amount of normal butane is re
moved in the low-boiling fraction, which is passed
in said zone to form the monosulfone, prevent
ing formation of heteropolymeric, reaction" prod
ucts of butadiene and sulfur dioxide by continu
ously maintaining in said zone isobutylene. in an
to separating unit 24*». The fractionation column
amount corresponding’ to from 2' to 10 per cent
[2 is so operated that butadiene, concentrated in’
of the total hydrocarbons present as the sole sup~
the kettle, is reacted with sulfur dioxide to form
pressor of such heteropolymeric reaction prod—
monomeric butadiene-culfone. The high-boiling
fraction, containing butenes and the butadiene 40 ucts, continuously removing the reacted mixture
from said zone, and volatilizing the volatile un
sulfone, is passed directly from the bottom of
reacted materials from said removed reacted mix
fractionation column #2 to ?ash vaporizer 56.
ture at a. temperature not exceeding, 100° C. to
Vapors are passed to separating unit 69, and a
leave butadiene monosulfone addition product as
normal butene fraction is recovered and also
' . ,
passed to dehydrogenation unit H2. Butadiene u a residue;
3. The continuous process of separating iso
is recovered from decomposition of the buta
prene from admixture with other close-boiling
diene-sulfone.
V
more saturated hydrocarbons which comprises
Itwill be seen from these examples that our in
continuously feeding said isoprene-containing hy
vention may be satisfactorily applied in several
modi?cations. While these examples illustrate '1' drocarbon. mixture and from one-half to three
times its weight of sulfur dioxide into a reaction
various preferred modes of operation, the limits
zone, the amount of said sulfur dioxide being in
so illustrated are not to be applied to limit unnec
excess of that molecularly equivalent to the diole
essarily the broader aspects of our invention.
While the invention has been disclosed and dis
?n present in said mixture, maintaining the tem
cussed primarily in connection with continuous
operation, intermittent operation of the inven
perature of said zone between 60° and. 80° C.,
maintaining said hydrocarbon mixture and sul
fur dioxide in liquid phase in said zone by the
maintenance of elevated pressure in said zone,
reacting substantially all free isoprene with sul
fur dioxide in said zone to form the monosulfone,
preventing formation of heteropolymeric reaction
products of isoprene and sulfur dioxide by con
tinuously maintaining in said zone unsym-methyl
ethyl ethylene in an amount corresponding to
from 2 to 10 per cent of the total hydrocarbons
present as the sole suppressor of such heteropoly
tion, or of one or more parts of the combination
process discussed, may at times be found advan
tageous and is not to be considered outside of
the spirit of the disclosure and teachings.
ductionof other diole?ns may be accomplished in
similar operations.
This application is a division of our prior and
copending application Serial No. 386,324, ?led
April 1, 1941.
.We claim:
1. The continuous process of separating ali
phatic conjugated diole?ns ‘from admixture with
other close-boiling more saturated hydrocarbons
which comprises continuously feeding said diole
?n_containing mixture and from one-half to
meric' reaction‘ products, continuously removing
:'
the reacted mixture from said zone, and volatiliz
ing the volatile unreacted. materialsfrom said re
moved reacted mixture at a ‘temperature not.ex~
ceeding 100° C. to leave isoprene monosulfone
three times its weight of sulfur dioxide into a re
action zone, the amount of said sulfur dioxide be
addition product as a residue.
ing in excess of that molecularly equivalent to the
ylene from admixture with other close-boiling
more saturated hydrocarbons which comprises
diole?n present in said mixture, maintaining the
4. The continuous process of separating'piper
2,407,825
13
continuously‘ feeding said piperylene-containing
said column a concentration of unsym-methyl-v
hydrocarbon mixture and from one-half to three
times its weight of sulfur dioxide into a reaction
zone, the amount of said sulfur dioxide being in
excess of that molecularly equivalent to the diole
?n present in said mixture, maintaining the tem
perature of said zone between 60° and 80° C.,
maintaining said hydrocarbon mixture and sul
fur dioxide in liquid phase in said zone by the
maintenance of elevated pressure in said zone,
reacting substantially all free piperylene with sul
ethylethylene in an amount corresponding to
from 2 to 10 per cent of the total hydrocarbons
present such as to prevent formation of hetero
fur dioxide in said zone to form the monosulfone,
preventing formation of heteropolymeric reaction
products of piperylene and sulfur dioxide by con
tinuously maintaining in said zone unsym-methyl '
ethyl ethylene in an amount corresponding to
from 2 to 10 per cent of the total hydrocarbons
present as the sole suppressor of such ,heteropoly
continuously withdrawing from said column an
overhead of said azeotrope of pentane with sul
fur dioxide and a bottoms product containing said
monosulfone and said pentene and relatively free
from unreacted piperylene.
‘
7. The continuous process of separating iso~
prene from admixture with close-boiling pentene
and pentane which comprises continuously feed
ing said isoprene-containing mixture and from
one-half to three times its weight of sulfur diox
ide into a fractional distillation column, the
5. The continuous process of separating butadi
ene from admixture with butene and butane
amount of said sulfur dioxide being so much in
excess of that molecularly equivalent to the di»
ole?n present in said mixture that free sulfur di
oxide is present in the bottom of said column at
all times, operating said column with a bottom
temperature of 80° C, and a top temperature of
60° C., fractionally distilling in said column in
such manner that substantially all of said iso»
prone and pentene is concentrated in the bottom
portion thereof in admixture with an excess of
which comprises continuously feeding said butadi
sulfur dioxide and said pentane forms an azeo
meric reaction products, continuously removing
the reacted mixture from said zone, and volatiliz
ing the volatile unreacted materials from said
removed reacted mixture at a temperature not
exceeding 100° C. to leave piperylene monosulfone
_
polymeric reaction products of piperylene and
addition product as a residue.
‘
trope with sulfur dioxide, reacting substantially
ene-containing mixture and from one-half to
all of said isoprene with said sulfur dioxide in the
three times its weight of sulfur dioxide into a
fractional distillation column, the amount of said 30' bottom portion of said column to formisoprene
sulfur dioxide being so much in excess of that
monosulfone, continuously maintaining in said
column a concentration of unsym-methylethyl
ethylene in an amount corresponding to from 2
to 10 per cent of the total hydrocarbons present
in the bottom of said column at all times, oper
ating said column with a bottom temperature of . 1 such as to prevent formation of heteropolymeric
reaction products of isoprene and continuously
80° C. and a top temperature of 60° C., fractional
withdrawing from said column an overhead of
ly distilling in said column in such manner that
said azreotrope of pentane with sulfur dioxide and
substantially all of said butadiene and butene is
a bottoms product containing said monosulfone
concentrated in the bottom portion thereof in
and said pentene and relatively free from unre
‘ admixture with an excess of sulfur dioxide and
acted isoprene.
said butane forms an azeotrope with sulfur diox
8. A continuous process of separating an ali-~
ide, reacting substantially all of said butadiene
molecularly equivalent to the diole?n present in
said mixture that free sulfur dioxide is present
with said sulfur dioxide in the bottom portion of
said column to form butadiene monosulfone, con
tinuously maintaining in said column a concen- ‘ -
tration of isobutylene in an amount correspond
ing to from 2 to 10 per cent of the total hydro
carbons present such as to prevent formation of
heteropolymeric reaction products of butadiene
and sulfur dioxide, and continuously withdrawing "
from said column an overhead of said azeotrope
of butane with sulfur dioxide and a bottoms prod
uct containing said monosulfone and said butene
and relatively free from unreacted butadiene.
6. The continuous process of separating piper
phatic conjugated diole?n from admixture with
close-boiling corresponding olefin and paraf?n
which comprises continuously feeding said diole
?n-containing mixture and from one-half to
three times its weight of sulfur dioxide into frac
tional distillation column, the amount of said sul»
fur dioxide being so much in excess of that mo
lecularly equivalent to the diole?n present in said
mixture that free ‘sulfur dioxide is present in
the bottom of said column at all times, operating
said column with a bottom temperature of 80° C.
and a top temperature of 60° C. fractionally dis
tilling in said column in such manner that sub
stantially all of said diole?n and ole?n is con
ylene from admixture with close-boiling pentene
centrated in the bottom portion thereof in ad
and pentane which comprises continuously feed
ing said piperylene-containing mixture and from
mixture with an excess of sulfur dioxide and said
paraffin forms an azeotrope with sulfur dioxide,
one-half to three times its weight of sulfur di
oxide into a fractional distillation column, the 60 reacting substantially all of said diole?n with
said sulfur dioxide in the bottom portion of said
amount of said sulfur dioxide being so much in
column to form diolefin monosulfone, continu- ‘
excess of that molecularly equivalent to the di
ously maintaining in said column a concentra
ole?n present in said mixture that free sulfur
tion of branched-chain monoole?n corresponding
dioxide is present in the bottom of said column at
all times, operating said column with a bottom 65 to said diole?n in an amount corresponding. to
from 2 to 10 per cent of the total hydrocarbons
temperature of 80° C. and a top temperature of
present such as to prevent formation of hetero
60° C., fractionally distilling in said column in
polymeric reaction products of diole?n and sul
such manner that substantially all of said piper
fur dioxide and continuously withdrawing from
ylene and pentene is concentrated in the bottom
portion thereof in admixture with an excess of 70 said column an overhead of said azeotrope of par
affln with sulfur dioxide and a bottoms product
sulfur dioxide and said pentane forms an azeo
containing said monosulfone and said ole?n and
relatively free from unreacted diole?n.
9. The continuous process of separating ali
ylene monosulfone, continuously maintaining in 75 phatic conjugated diole?ns from a mixture con
trope with sulfur dioxide, reacting substantially
all of said piperylene with said sulfur dioxide in
the bottom portion of said column to form piper
15"
2,407,825
16v
taining same together with other close-boiling
more Saturated hydrocarbons which comprises
continuously feeding said diole?n-containing mix
ture and from one-half to three times its weight
of said zone between 60° and 80° C.’, maintaining‘
said hydrocarbon mixture and said sulfurdioxide
in liquid phase in said zone by the maintenance
of elevated pressure in said zone, reacting sub
of sulfur dioxide into a reaction zone, the amount 01 stantially all free isoprene with sulfur dioxide in
of said sulfur dioxide being in excess of that
said zone toform the monosulfone, said isoprene
molecularly equivalent to the diole?n present in
containing ,mixture containing an insufficient
said mixture, maintaining the temperature of said
amount of unsym-methyl ethyl ethylene to sup
zone between 60° and 80° C., maintaining said
press formation of heteropolymeric reaction prod
hydrocarbon mixture and sulfur dioxide in liquid 10 ucts of isoprene and sulfur dioxide, continuously
phase in said zone by the maintenance of ele
and separately introducing into said reaction zone
vated pressure in said zone, reacting substantial
unsym-methyl ethyl ethylene in amount such as
ly all free diole?n with sulfur dioxide in said zone
to continuously maintain in said zone an amount
to form the monosulfone, said diole?n-containing
of unsym-methyl ethyl ethylene sui?cient to ,pre~
mixture containing an insufficient amount of 15 vent formation of such heteropolymeric reaction
branched chain moloole?n having the same num
products, said unsym-methyl ethyl ethylene being
ber of carbon atoms per molecule as said diole?n
to suppress formation of heteropolymeric reaction
products of said diole?n and sulfur dioxide, con
the sole suppressor of such heteropolymeric. re
action’ products in said reaction zone, continuous
ly removing the reacted mixture from said zone,
tinuously and separately introducing into said 20 and resolving the withdrawn reaction mixture
reaction zone branched chain monole?n having
the same number of carbon atoms per molecule
as said diole?n in amount. such as to continuously
maintain in said zone an amount of branched
chain monoole?n sufficient to prevent formation 25
of such heteropolymeric reaction products, said
branched chain monoole?n being the sole sup
pressor of such heteropolymeric reaction products
in said reaction zone, continuously removing the
into the sulfone and unreacted materials.
12. The continuous process of separating piper
ylene from admixture with other close-boiling
more saturated hydrocarbons which comprises
continuously feeding. said piperylene-containing
mixture and’ from one-half to three times its
weight of sulfur dioxide into a reaction zone, the
amount of said sulfur dioxide being in excess of‘
that molecularly equivalent to the diole?n present
reacted mixture from said zone and resolving the 30 in said mixture, maintaining the temperature of
withdrawn reaction mixture into the sulfone and
said zone between 60° and 80° C., maintaining
unreacted materials.
said hydrocarbon mixture andsaid sulfur dioxide
10. The continuous process of separating buta
in liquid phase in. said zone by‘ the maintenance
diene from admixture with other close-boiling
of elevated pressure in said zone, reacting sub
more saturated hydrocarbons which comprises 35 stantially all free piperylene with ‘sulfur dioxide
continuously feeding said butadiene-containing
in said zone to form. the 'monosulfone, said piper
mixture and from one-half to three times its
ylene-containing mixture containing an insuf
weight of sulfur dioxide into a reaction zone, the
?cient amount of unsym-methyl ethyl ethylene
amount of said sulfur dioxide being in excess of
to suppress formation of‘ heteropolymerie reaction
that molecularly equivalent to the diole?n pres 40 products of piperylene and sulfur dioxide, con
ent in said mixture, maintaining the temperature
tinuously and separately introducing into said re
of said zone between 60° and 80° 0., maintaining
action zone unsym-methyl ethyl ethylene in
said hydrocarbon mixture and said sulfur dioxide
amount such as to continuously maintain in said
in liquid phase in said zone by the maintenance
zone an amount of unsym-methyl ethyl ethylene
of elevated pressure in said zone, reacting sub 45 sumcient to prevent formation of such hetero
stantially all free butadiene with sulfur dioxide
polymeric reaction products, said unsym-methyl
in said zone to form the monosulfone, said buta
ethyl ethylene being the sole suppressor of such
diene-containing mixture containing an insuf
heteropolymeric reaction products in said reac
?cient amount of isobutylene to suppress ‘forma
tion zone, continuously removing the reacted mix
tion of heteropolymeric reaction products of buta
ture from said zone, and resolving the withdrawn
diene and sulfur dioxide, continuously and sep
reaction mixture into the sulfone and unreacted ~
arately introducing into said reaction zone iso
materials.
butylene in amount such as to continuously main
13. The process of claim 9' wherein the amount
tain in said zone an amount of isobutylene suf
of said branched chain ole?n maintained in said
?cient to prevent formation of such heteropoly 55 zone is between 2 and 10 per cent of the total
meric reaction products, said isobutylene being
hydrocarbons present.
the sole suppressor of such heteropolymeric re
action products in said reaction zone, continu
14. The process of. claim 10 wherein the amount
of said isobutylene maintained in said reaction
ously removing the reacted mixture from said
zone, and resolving the withdrawn reaction mix
ture into the sulfone and unreacted materials.
11. The continuous process of separating iso
prene from admixture with other close-boiling
more saturated hydrocarbons which comprises
continuously feeding said isoprene-containing
mixture and from one-half to three times its
weight of sulfur dioxide into a reaction zone, the
amount of said sulfur dioxide being in excess of
that molecularly equivalent to the diole?n pres
ent in said mixture, maintaining the temperature 70
zone is between 2 and 10 per cent of the total
hydrocarbons present.
15. The process of claim 11 wherein the amount
of unsym-methyl ethyl ethylene maintained in
said reaction zone is between 2 and 10 per cent
of the total hydrocarbons present.
16. The process of claim 12 wherein the amount
of unsym-methyl ethyl ethylene maintained in
said reaction zone is between 2 and 10 per cent
of the total hydrocarbons present.
'
FREDERICK E. FREY.
ROBERT D. SNOW.
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