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Патент USA US2403672

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' July 9, 1946.
Filed Nov. 13, 1943
BUTE NE ‘- l
g 4701/ 4
Patented July ,9, 1,946
Maryan P. Matuszak, Bartlesville, Okla, assignor
to Phillips Petroleum Company, a corporation
7 of Delaware
f Application November 13, 1943,>ScrialNo. 510,185
3 Claims. (01. 2s0_ess.2,)
midway between the top and the bottom of the
p This invention relates to the treatment of mix
tures of ole?ns of closely adjacent boiling points,
' fractionator.
more particularly to the separation of an iso
ole?n from the corresponding l-ole?n, and still
more particularly to the separation of isobutylene
from butene-l.
, most suitable for the conversion of butene-l to
butene-2. The temperature used is preferably
such that isomerization of butene-l to butenes-2
For many purposes, it is advantageous or de- ‘
sirable to obtain a substantially ,pure‘ isoole?n
is the principal or sole reaction, and that isom»
erization of normal butene to isobutylene is
from a mixture containing also one or more close
boiling normal ole?ns, as for example, to ob
The column operates at a tem
perature, below the critical temperature of iso
butylene (approximately 293° F.), that is found
substantially precluded. Temperatures ranging
tain isobutylene from a mixture containing also
butene-l and perhaps butene-2.- Although it is
from about 150° F.,to about 250° F. are pre
readily possible, by fractional distillation, to sep~ ‘
as low as room temperature, or at higher tem
ferred, although operation at lower temperatures,
arate butene-2 from butene-l and isobutylene,
peratures, say up to about 290° F., may be prac
the separation of isobutylene from butene-l by 15 ticed provided the slow reaction rates at the lower
fractional distillationis extremely diflicult and
temperatures or the slightly increased tendency
expensive because of the closeness of the boiling
,to deactivation of the catalyst at the higher tem
points. The boiling point of butene-l is -6.l° C. a
and that of isobutylene is -—6.6° C. Accordingly,
peratures are not objectionable. The column
pressure is always above atmospheric when op
in the past it has been necessary to resort to 20 erating’ at temperatures above the boiling point
of the feed at atmospheric pressure. The frac
tionationcolumn is provided with the means for
applying heat at the bottom and for removing
costly and complex azeotropic distillations, sol
vent extractions, and chemical separations, in or
der to separate these two ole?ns. But butene-Z,
the two forms of which boilat +1.0 and 3,7? 0.,
can be readily separated from isobutylene by
fractional distillation.
By the practice of this invention, a mixture of
hydrocarbons which contains isobutylene and bu
‘heat, to» establish refluxing at the top. The op
erating pressure in the column is easily adjusted
‘to any desired level by controlling the column
temperature, as is well understood in the art. .
The pressure is adjusted, to maintain both liquid
tene-l, and which may Or may not contain bu~
and vapor states so as to produce a suitable de
tenes-2, is processed in asingle fractionation
isomerization tower or column to separate the
gree of fractionation. The size of the column
and the thickness of the bed or beds of cata
isobutylene from other butenes. The upper two
lyst depend upon the rate of throughput of hy
thirds or thereabouts of the column is packed
drocarbons and the purity of products desired.
with an isomerization catalyst which is capable
That is, the greater the degree of fractionation
of effecting the isomerization of butene-l to bu- i Ll and the purer the isobutylene desired, the thicker
tenes-2 as substantially the sole reaction‘under
must be the catalyst bed in the fractionating col
the conditions maintained in the distillation col
umn. If the thickness of the beds in the col
umn. The isobutylene is fractionally distilled
umn remains constant, and a purer overhead
from the butenes-2 and is removed as an over
product of isobutylene is desired, it is necessary
head product. The butenes-2 is removed as a v to use a higher re?ux ratio which will require
kettle product. The catalyst acts not vonly to
a fractionator that is larger in cross-sectional
promote the isomerization reaction, but also as
packing material in the column to fractionate
Any suitable solid catalyst which is effective
the butene-l and isobutylene from the higher
under Vapor-liquid conditions, such as the cata
boiling butenes-2. The lower part of the column 45 lysts mentioned in my copending applications
is packed with a non-isome‘rizing packing, or it
Serial No. 441,705 ?led May 4, 1942, and Serial
may contain other fractionating devices perform
No. 467,873 ?led December 4, 1942, may be used.
ing the function of fractionating plates, whereby
Among preferred catalysts are those comprising
I the higher-boiling butenes-Z works its way down
black chromium oxide; other especially suitable
ward and eventually passes from the column.
catalysts include granular magnesia, chromia and
brucite. Ordinarily, a catalyst effecting ole?n
It is undesirable to ?ll the lower part of the
column with catalyst because of the reverse isom
isomerization without appreciable change in the
erization of butene-2- to butene-l which would . carbon skeletal structure is preferred.
occur. The feed mixture’ comprising butene-l
An advantage of this invention is the removal
and isobutylene enters the tower at a point about 65 of butene-2 from the unisomerized butene-l as
rapidly as the butene-2 is formed. This is ac
complished by the fractionation that is taking
place in the presence of the catalyst. This keeps
the concentration of butene-2 low in the pres
tenes-Z” are intended to include either the single
ence of butene-l, and consequently promotesthe
isomerization reaction according to the following
2-ole?n or a mixture of the isomeric 2-ol?ns.
Since the invention may be practiced otherwise
than as speci?cally described, and since minor
variations and modi?cations of it will be obvious
to those skilled in the art, it should not be re
stricted otherwise than as speci?ed in the ap
equation for the equilibrium constant:
pended claims.
- '
I claim:
: Cbutene-l
1. The method of separating isobutylene from
butane-1 which comprises introducing a feed con
The lower section of the tower not only provides
a means for separating the isobutylene from the
butene-2 formed from butene-l but also pro
taining said isobutylene and butene-l into a frac~
tionation-isomerization column packed with a
solid catalyst which is capable of effecting the
vides for the separation of the isobutylene from
15 isomerization of butene-l to butenes-2 under con
any butene-Z present in the feed.
ditions maintained in the column, passing the
By fractional distillation of the mixture in the
same column in which the isomerization occurs, ’
feed over the solid catalyst under conditions of
the number of treatments to produce nearly pure
isobutylene is decreased below that which would
be required if the isomerization and the fractiona
temperature and pressure such that liquid and
tion occurred in separate chambers. That is, by
the practice of this invention it is theoretically
substantially the sole reaction without substan
vapor phases are maintained and such that the
catalytic conversion of butene-l to butenes-Z is
tially affecting the isobutylene, ‘removing isobu
tylene as an overhead product and removing bu
tenes-2 as a kettlevproduct byiractional distilla
butylene desired as an overhead product and
almost ‘any purity of butene-2 as a kettle product. 25 tion in the single fractionation-isomerization
In contrast, if the isomerization and the fraction
2. The method of claim 1 wherein the tempera
ation are conducted in separate chambers, the
isomerization reaction can only reach equilibrium
ture of the fractionation-isomerization column is
possible to produce any degree of purity of iso
between the butene-2 and butene-l present, and
several successive treatments may be required to
produce a very pure grade of isobutylene; in
addition, this method almost necessitates the re
moval of any butene-2 before the feed mixture
comprising butane-1 and isobutylene is admitted
to the isomerization chamber.
maintained between 150° F. and 250° F.‘
3. The method of separating isobutylene from
The accompanying drawing, which is self-ex
planatory, portrays an arrangement of equipment
butene-l to butenes-2 and functions both to cata
butene-l which comprises introducing a feed con
taining isobutylene and butene-l into a fractiona
tion-isomerization column wherein the upper
part of said column is packedwith a solid cata
lyst capable of effecting the visomerization of
lyze said isomerization and to fractionate bu
tenes-2 from the isobutylene and butene-l and
useful in carrying out the present invention.
the lower part of said column is provided with a,
The process of this invention is preferably ap
plied to the separation of isobutylene from bu 40 non-catalytic fractionating means functioning
only to separate butenes-2 as a bottoms product,
tene-l. It is not equally applicable to the sep-v
passing the feed over the solid catalyst under con
aration of an isoole?n having more than four
ditions of temperature and pressure such ‘v that
carbon atoms per molecule from the correspond
liquid and vapor phases are maintained and such
ing l-ole?n because such isoole?n itself under
that ‘the catalytic conversion of butene-l tov bu
goes isomerization; for example, isoamylene (2
tenes-2 is substantially the sole reaction without
methyl-butene-l) is isomerized to trimethylethyl
ene (2-methylbutene-2).
Attention is directed to the copending applica
tion of H. E. Drennan, Serial No. 459,589 ?led
September 24, 1942, which describes the separate
isomerization of butene-l to butene-2 and frac
tional distillation to separate the isobutylene.
As used herein the terms “butene-2” and “bu
substantially affecting the isobutylene,‘ removingv
isobutylene as an overhead product and remov
ing butenes-2 as a kettle product by fractional
distillation in the single fractionation-isomeriza
tion column.
Certi?cate of Correction
Patent No. 2,403,672.
_ July 9, 1946.
It is hereby certi?ed that error appears in the printed speci?cation of the above
numbered patent requiring correction as follows: Column 4, line 8, after-the word and
period “claims.” insert the following paragraph—
This application is a continuation-in-part of my prior and copending application,
Serial No. 441,705, filed May 4, 1942.
and that the said Letters Patent should be read with this correction therein that
the same may conform to the record of the case in the Patent Of?ce.
Signed and sealed this 29th day of October, A. D. 1946.
First Assistant‘ Oommz'ssioner of Patents.
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