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>946
' ~
2,408,752
uuirso stares PATENT} orricev
. PREPARATION or BRANCHED CHAIN .
HYDROCABBONS
.
Robert E. Burk, Cleveland Heights, Ohio, assignor
to The Standard Oil Company, Cleveland, Ohio, '
N0 Drawing. Application April. 18, 1942,
.
Serial No. 439,543
2 Claims. lCl. 260-45835)
In the common procedure of catalytic isomeri-
' plehydrogen bromide, hydrogen chloride, hydro
zation, there is considerable side reaction of
breaking up of molecules or cracking. This in-
gen ?uoride; and these may be in liquid or gas
eous state. Pressures up to 200 pounds‘ per
terferes with the production of the ‘desir 'd kind
square inch maybe applied in the reaction Zone
of hydrocarbons, and also represents ‘a 'corre-v 5 with the halide in‘the gaseous state. vWhen the
spending amount of waste of material." I have
hydrogen halide is maintained as a-liquid suffi
found that if isomerization be carried first to only
eierlt Pressure is used to preserve the liquid
a slightly branched condition and an isomer be
‘phase. An especially effective catalyst is a liquld
iractioned out relatively clean from the reaction
EFL-Eli's catalyst, the partial pressure of boron
mixture, th'is clean out can be then isomerized 10 ?uoride being 50 to 550 pounds per square inch,
quite
. drastically
without
cracking.thus
Di?erent
equilibrium
conditions
are involved
stage-
preferably
150 pounds
The operating
temperatures in general desir
wise, instead of in the customary run-through
with a starting material, and the usual cracking
ably are 10W,11nder 00° C. Preferably they may
be below ordinary temperature and in the range
loss
may
be obviated, and desired isomer prod- 15 011Where
down todesired,
minus 25
01' 30° C may be present, 1-10
uctsbe
obtained.
isobutane
To the accomplishment of the foregoing and
111015, Preferably 2 01‘ 3 mole Hydrogen may de
related
the invention,
then, comprises
the ~ sir'ably
also be Presentto be treated are , subjected
featuresends,
hereinaiter
fully described,
and particrl‘he hydrocarbons
ularly pointed out in the claims, the following 20 to the aforedescribed conditions for a time de
description setting forth‘ in detail certain illuspending on the temperature, the particular com
trative embodiments of the invention, these being
position of the catalyst, etc. to convert them to
indicative however, of but a few of the various
slightly branched hydrocarbons. Then, the hal
ways
in
which
the
principle
of
the
invention
may
are removed,
such‘desiredway,
as by freezing
be employed.
25 ide
out, catalysts
or by distillation
or other
and
As raw material, hydrocarbons which it is dethe hydrogen halide may be removed by releas
sired to isomerize, in general may be applied.
ins Pressure, neutralizing, 6110- Then the Prod
The light hydrocarbons, as of live to eight carbon
‘lets are fractionated to Separate the Slightly
atoms are especially applicable. Naphthas may _ branched hydrocarbons, and slleh thus in rela
be thus treated. rI‘hese are desirably fraction- 30 tively pure form are then subjected to the afore
ated mto cuts corresponding to hydrocarbons 0
described conditions to isomerize them into more
a given number of carbon atoms which are then
highly branched hydreeerben?- Where desired,
isomerized separately. The hydrocarbons to be
this product may be then fractionated, and a rela
isomerized in the ?rst step or the operation may
tively pure branched isomer may be again ‘fur
be normal saturated hydrocarbons. Any con- 35 thel‘ ell-‘elected t0 the isemei‘izatien
venient, source of hydrocarbons may be used how_
As an example: N-hexane is treated with 10 mol
ever. In some cases it is desirable to start with
slightly branched hydrocarbons. Where the hydrocarbon 00115 or raw material contain unsa —
p91‘ cent of A1311 P1115 H131‘, the temperature be
mg not higher than 0° . o and Preferably the
Operation being Started at mlml 2 C Atter
urated and aromatic hydrocarbons in addition to 40 about 130 hours, depending upon the precise tem
paraf?n hydrocarbons, these may be removed, ‘for
example by extracting with selective solvents or
by reacting with halides for that purpose.
petetlll'ee maintained, the product contains
something over half isomers, 2-methyl pentane
being largely predominant Ome neOheXane is
' As catalysts, the halide catalysts in general
@150 formed The product is fractionated, and
may be employed. Advantageous are the alumi- 45 the 2-methyl pentehe out is sublected to 10 mol
num halide catalysts, such as aluminum chloride,
per cent of aluminum bromide and hydrogen bro
aluminum bromide, or complexes formed by these
mide at about minus 11° C. for about 217 hours.
halides with hydrocarbons, or alkyl halides may
The product is mostly more highly isomerized
be used; also other halides such as acid-acting
hexanes, especially 3-methyl pentane, and small
halides of zinc, iron, arsenic, antimony, tin, 5() er amount of 2,3-dimethyl butane. These may
boron, etc. Mixtures of such catalysts are 'debe fractionated'out and again be separately sub
sirable in some instances. The amount of cata-
jected to the halide catalyst for further isomeriz
lyst
may be 1 to
mol per tocent
basedthe
on halthe
ation.
hydrocarbon.
It is10desirable
promote
As another example: 3-methyl pentane is treat
ide catalyst by a hydrogen halide, as for exam- 55 ed at minus 11° C. with 10 mol per cent AlBI's
___.-—
2,408,752
As another example: 2,3—dimethyl ‘ butane
treated as in the foregoing example yields a prOd-
‘ ~
orm more highly branched iso e
process for converting normal to slightly
not containing 76.4 per cent of isomeric hexanes, 10' branched hydrocarbons to highly branched iso
2 per cent being neohexane. No isobutane is
formed, and only 0.1 per cent of isopentane.
ther modes of applying the principle of the
invention may be employed, change being made
mers by a unitary two-stage process, which com
prises subjecting hydrocarbons having 5 ‘to 8 car
bon atoms~closely fractionated to contain pri
marily normal to slightly branched para?inic hy
aS regards the details described, provided the 15 drocarbons of the same number of carbon
e equivalent of such be employ d
catalyst promoted by hydrogen halide at a tem
therefore particularly point out and distinctperature below ordinary temperature to form 1so~
y aim' as my invention:
mers slightly more branched than said starting
A process for convelting normal to slightly 20 hydrocarbons, separating the so-formed slightly
branched hydrocarbons to highly branched iso
branched isomers from the remaining hydrocar
mers by a unitary two-stage process, which com
bons and subJectmg said separated isomers to
prises subJectmg hydrocarbons having 5 to 8 car
furt er isomerization W1 h an alummum halide
on atoms~closely fractionated to contain pncatalyst promoted by a hydrogen halide at a tern
marily'normal tolslightly branched para?inic hy- 25 perat'ure below ordinary temperature to form
drocarbons of the same number of carbon
more highly branched isomers.
atoms-t0 isomerization with a halide catalyst at
ROBERT E. BURK.
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