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Патент USA US2403439

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2,403,439
Patented July 9, 1946 '
UNITED STATES PATENT orrlce
>
2,403,439
‘PROCESS FOR ISOMERIZING MONO
OLEFINS
'
Vladimir N. Ipatieff and George S. Monroe, River-v
side‘, ‘111;, assignors to Universal Oil Products
Company, Chicago, 11]., a corporation of Dela- I
ware, '
No Drawing. Application August 19, 1943,
'
Serial No. 499,252
8Claims.
(c1. zoo-683.2) '
.
sion of hydrocarbons and is more'particularly di
rected to the shifting of the position of the
double bond in an ole?nic hydrocarbon by cat
alytic means.
'
‘
‘H,
.
Y.
-
.
would be practically impossible bylfractionation.
However, itis also evidentthat if the butene-l
can be converted to butene-2, the separation can
_
In view of the recent developments in the pe
troleum industry,‘ particularly in the manufac
ture of aviation gasolines and synthetic rubber,
methods for shifting the position of the double
bond in ole?nic hydrocarbons have become in
2
It is apparent from the above table that the
vseparation of the individual hydrocarbons, more
particularly isobutene from normal butane-1,
The present invention relates to the conver
be accomplished with comparative ‘ease.
~
Various catalytic materials have been proposed
forthe isomerization ofole?nssuch as silica gel,
10 alumina, bauxites, alruninum sulfate», concen
creasingly important. It has, been found that
alkymers produced by alkylation of normal bu
trated solutions of zinc chloride, benzene sulfonic
acid and so forth. However,;these catalysts also
tene-2 possess more desirable antiknock proper
tend to promote undesirable side reactions such
ties than those produced by alkylation of the
as polymerization to produce high boiling poly
isomer normal butene-l. In the manufacture of 15 mers regardless of the operating conditions em
synthetic rubber, the length of the chain in the
high molecular weight polymers produced by
polymerization of such compounds as isobutene
with butadiene or styrene depends in a large
measure on the purity of the reactants and con
ployed in the reaction.
.
.
-‘
It is an object of this invention to present a
method for selectively utilizing the shifting of
the double bond- within an ole?n hydrocarbon
20 Without substantial polymerization ‘of the ole?n
to higher boiling hydrocarbons.
trols to a certain extent the physical and chemi
cal properties of the resultant rubber. It is,
therefore, essential in the manufacture of these
synthetic rubbers that the reactants be of a high
degree of purity. Similarly, the catalytic dehy 25
drogenation of butenes into butadienelone of the
principal reactants in rubber manufacture, is per
It is another object of this invention to pro
vide a method of shifting thGgDOSitlOl’l of the
double bond of ole?nic hydrocarbons without
changing the structural arrangement of the car
bon atoms, in the hydrocarbon molecules.
We have discovered a select group of catalysts
formed more readily with-less carbon formation
which may be employed over a wide range of
and greater butadiene yields when the dehydro
genation charge is substantially free from iso
operating conditions to accomplish the objects
30 mentioned.
In one broad aspect, the present invention con
sists of a process for shifting the position of the
double bond in an ole?nic hydrocarbon which
butene. Thepresent invention provides a method
of separating the C4 ‘hydrocarbons to produce
products of sufficient purity that they may be
satisfactorily employed in synthetic rubber man
ufacture and in the production of butadiene.
It is well known that a C4 hydrocarbon fraction
cannot be separated into the individual C4 hy
comprises subjecting said ole?nic hydrocarbon
35 to contact under ole?n isomerizing conditions
with a catalyst comprising a dilute aqueous so
lution of a strong non-oxidizing acid.
We have found that the double bond, contained
drocarbons by simple fractional distillation since
the boiling points-of the varlous'hydrocarbons are
somewhat similar. This is particularly true with
a mixture of C4 ole?ns containing isobutene and
normal butene-l, or a mixture containing these
40
in ole?n hydrocarbons such. as butene-l, pen~
tene-l, 2.3-‘dimethyl butene-l, andthe like can
be shifted by the in?uence of catalyst materials
comprising dilute aqueous solutions of strong
non-oxidizing acids such as hydrogen chloride,
hydrogen bromide or dilute acidic solutions of
ole?ns and C4 para?ins. The following table
gives the boiling points of the various C4 hydro
45 easily hydrolyzed' salts of such acids such .as am
carbons at one atmosphere pressure.
monium chloride, iron chloride. nickel chloride.
manganese chloride, magnesium chlorideand the
Boiling points at 1 atmvsphere'pressure
corresponding bromides, and the like. i
‘
°C.
The operation maybe conducted over wide
Isobutane ___________ __; _______ __‘ _____ __
—11.8
Isobutene ____________________________ __
+6.6
Normal butane-1 ____________________ -fNormal butane _____________________ __»__r
—6.4
—0.5
ranges of temperature and pressure depending
primarily upon the hydrocarbon being isomerized
and the catalyst employed. Generally speaking,
temperatures within the range of about 25‘ to
400° 'C., preferably 150. to '300“ 0.’, and pressures
of subatmospheric, atmospheric or substantially
Normal butene-2 trans ____________ __'____
+1
Normal butene-z cis ____ -a ___________ __,_
+3.7
2,403,439
3
superatmospheric pressure may be satisfactorily
higher once through yields of butene-2 in the
products.
employed. To maintain the selectivity of the
The reaction may be conducted in a series of
reaction, the catalyst concentration in the aque
isomerization zones with intermediateseparation
ous solution must be carefully controlled. The
solution should be mildly acidic, preferably at a 5 ‘of the isomerized product to effect a substantially
complete conversion of the olefin to the desired
pH of about 3 or more. The exact pH of the
catalyst solution is dependent upon the charge .
isomer.
and operating conditions used and is best deter-' ‘
The following examples are introduced as illus
mined by small scale experimental tests. ' '
- 1
trative of: the :results obtainable in the practice
Various methods of operating may be employed: "10 of the present process in the isomerization of
For example, the vapors of the charging stool;
butene-lto butene-Z and isomerization of 2,3
may be bubbled upwardly through‘ stationary = dimethyl butene-l to 2,3-dimethyl butene-2, but
pools of dilute aqueous solutions of the catalyst } 7,, it is not intended that the scope of the invention
' should be limited-in exact accordance with the
or by similarly passing the vapors upwardly coun
tercurrent to the descending catalyst solution in
data presented.
7
vertical reactors containing ?lling'or'spacing‘m'a
terials such as, for example, granular fragments
'- ' ' "
of relatively inert materials such as silica, alu- ' ., .In run "No. 1 shown in Table I given below,
mina, ?rebrick and'the like, or regularly spaced '
weighed amounts of normal butene-l, Water and
pans and trays may beemployed to insure good 20 ammonium chloride were placed in a steel rotat
contact between the charge and catalyst solu
tions.
‘
ing autoclave containing a glass liner.v The reac
tion was conducted under the conditions shown in
Table I given below andv the products were re
.
Alternatively the reaction may be conducted
by passing the, ole?ns either alone or in admix
moved from the autoclave and analyzed.- -
ture with other hydrocarbons in, substantially
test in which similar quantities. of butene-Land
water were charged to the rotating autoclave.
catalyst solution through tubular elements un
der conditions of turbulent flow, the products
This run- was madeto determine whether the
from’ the tubular elements being passed into sep
water present in the autoclave had any isomer
arating chambers from which the hydrocarbon
izing activity. It is evident from .thedata pre~
products‘ are passed to a fractionator and the sep
sented in Table I that the sole catalytic, e?ect
was due to the presenceof the ammonium chlo
arated catalyst solutions returned for further
service. The separated catalyst solution may be
adjusted to ‘the proper pH by the addition of fresh
ride in the reaction vessel.
acid or salts prior to recycling to the tubular 35
elements.
>
'
Run No. 2 shown in-Table I is a- comparative
liquid‘phase and‘ a proportioned amount ' of a 7
>
TABLE, I
'
Still another method of conducting the reac~
tions consists of introducing the charge and cata—
lyst solution into a rotating vessel or a vessel pro
vided with some means of obtaining rapid mixing
of the hydrocarbon and catalyst such as, for
example, a Stratfor'd contactor‘ or turbo mixer,
‘
lsom‘erz'zatz'on of butene-I to buténc-Z with dilute
aqueous ammonium chloride solution
' -
passing the effluent from the vessel into a sep
Charge:
<-—- Normal butene-l -‘-->
aration zone wherein hydrocarbons are separated
from the’catalyst solution and recycling catalyst 45
Run No. 1 ;Run No. 2
solution containing the proper amount of ‘acid or
salt to the reaction vessel. The hydrocarbon
Time at operating temp, hours_ _ _
3
"
3
products are then fractionaly distilled to separate
Temp., ° O____r _______ __, _______ __
.
230
230
the converted from the unconverted hydrocarbons
Pressure, atmospheres __________ __
88-95
88-122
which later may be recycled to the reaction zone. 50 Charge: Weight per cent"
37. 3
36. 6
This invention is applicable not only to a single
61. 5
63. 4
ole?n hydrocarbon or mixtures of ole?nic hydro
Operating conditions:
carbons but also to mixtures of one or more ole
?ns with saturated hydrocarbons such as, for
example, the fractions obtained from the cata-. 55
lytic and thermal cracking of heavier hydro
carbon oils. It is particularly applicable to the 04
fractions of the aforesaid source and permits the
conversion of‘ butene-l’to butene-2 in the pres
ence of isobutene Without substantial conversion 60
of the isobutene to normal butenes or polymers.
It is, of course, evident that if the invention is
employed to separate C4 hydrocarbon fractions
to recover isobutene without contamination by bu-,
tene-l or to recover a maximum of butene-Z, the
‘as
'
.
>
‘
Since the isomerization reaction is an equi
librium reaction, this preliminary separation will
aid in the subsequent visomerization ‘operation.
The butene-2 ordinarily present ‘ in v‘the charge
would tend to decrease the rate of reaction; and
its removalprior to the isomerization will ‘permit’
l
.
7
_
1. 2
____________ __
Total _________________________ _.
100.0
100.0
Products, wt. per cent of butene-l
charged:
>
Butene-2 ________________________ __
Butened, recovered _____________ ..
C5+hydrocarbons _ _ _ _ _ _
Polymer ___________ __
04 alcohols __________ _.
_ _ . . _ . _ _
44,2
37.6
l. 0 >
~
1. 7
95. 2
0. 7
__ _.
0.0
0.0
___
5.3
0.0
Loss+uncondensable ga _
Total _________________________ __
11.9
2. 4
100.0
100. 0
EXAMPLE II
In Example‘II, results of which are shown in
Table II given below, weighed amounts of 2,3-di
methyl butene-l, water and ammonium chloride
butene-Z originally present in the fraction should
be removed by fractional distillation prior to the
desired isomerization operation.
,
76
were placed in a rotating autoclave similar to
that used in Example I. Two tests were» con~
ducted, run. No. 3 at 275° C. and run No. Zlat
230° C'. An analysis of the products indicated
that at least 50% of the 2,3-dimethyl.butenevl
was isomerized to 2,3-dimethyls buten€~2 :=Wi’th
very’ little polymerization, the extent of» poly.
merizatiorfbeing of the order of about 3%.
2,403,439
5
2. A process for isomerizing 2,3-dimethyl bu
tene-l to 2,3-dimethy1 butene-2 which comprises
contacting 2,3-dimethyl butene-l under isomer
Teen: II
Isomerz'aatz'on of 2,3-dimethyl butane-1 to 2,3-di
methyl butane-2 with dilute aqueous ammoni
ization conditions with a catalyst comprising a
dilute aqueous solution of ammonium chloride
um chloride solution
having a pH above about 3 but less than 7.
3. A process for shifting the position of the
Charging stock:
2,3-dimethyl butene-l
double bond in a mono-ole?nic hydrocarbon
Run N o. 3
which comprises contacting said mono-ole?nic
hydrocarbon at ole?n isomerizing conditions with
Run No. 4
a catalyst comprising an aqueous solution of an
Operating conditions:
Time at operating conditions ____ __
3
3
__
275
230
4 Pressure, atmospheres __________ __
Temp., ° C ________________ __
109-143
95-105
2,3-dimetl1yl butened ___________ __
47. 2
44. 2
Water __________________________ __
N H401 __________________________ _ _
51. 8
1. 0
54. 7
1. 1
Total _________________________ __
100. 0
100. 0
Charge: Weight per cent:
acid selected from the group consisting of hydro
gen chloride and hydrogen bromide, said aqueous
solution having a pH above about 3 but less
15 than 7.
4. An isomerization process ‘which comprises
converting a normal alpha ole?n into the corre
sponding normal beta ole?n by contacting said
alpha ole?n at ole?n isomerizing conditions with
Products, wt. per cent of 2,3-dimethyl
butene-l:
2,3-dimethyl butene-2 ___________ __
50.0
2,3-dimethyl butene-l (recovered).
33. 6
62. 7
32. 4 20
a catalyst comprising an aqueous solution of an
acid selected from the group consisting of hydro
gen chloride and hydrogen bromide and. main
Loss+uncondensable gas
13. 1
1. 3
taining the pH of said solution above about 3 but
Total _________________________ -100. 0
100. 0
below 7 to substantially avoid polymerization.
5. The process of claim 3 further character
25
The above examples indicate in a general way
ized in that said aqueous solution is formed by
the selectivity of the catalysts disclosed in this
dissolving in water a hydrolyzable salt of said
invention as to their in?uence on the shifting
acid.
of the position of the double bond of an cle?nic
6. The process of claim 3 wherein said mono
Polymer ______________ __
.-
O6 alcohols ____________ _ _
3 3
3 6
'
'
hydrocarbon, since high yields of isomeric ole 30 ole?nic hydrocarbon comprises butene-l.
?n hydrocarbons are obtained with very little
polymerization of the ole?nic hydrocarbons.
We claim as our invention:
1. A process for isomerizing butene-l to bu
7. The process of claim 3 wherein said mono
ole?nic hydrocarbon comprises 2,3-dimethy1 bu
tene-l.
8. The process of claim 3 wherein said mono
tuene-2 which comprises contacting normalrbu 35 ole?nic hydrocarbon comprises pentene-l.
tene-l under isomerization conditions with a cat
alyst comprising a dilute aqueous solution of am
monium chloride having a pH above about 3 but
less than 7.
VLADIMIR N. IPATIEFF.
GEORGE S. MONROE.
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