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Патент USA US2402807

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Patented June 2-5, 1946 '
2,402,807
‘ UNITED STATES PATENT OFFICE
ISOMERIZATION OF HYDROCARBONS
Gustav Eglo?, Chicago, 111., assignor to Universal
Oil Products Company, ChicagoJlL, a corpora
" tion of Delaware
No Drawing. Application May 25, 1942,
.
‘
Serial No. 444,430
11 Claims. (Cl. 260-6835)
1
2
This invention relates to a process for the pro
duction of highly branched para?in hydrocarbons
Y from normal or mildly branched para?in hydro
carbons by catalyzed isomerization reactions, and
the process is more specifically directed to the
manufacture or 2,2,3-trimethylbutane,
which
hydrocarbon is generally known as triptane.
In the para?in hydrocarbon series, it has been
established as a general rule that the more highly
branched compounds have higher knock ratings
than their less highly branched isomeric counter
parts. Thus, the iso-octane having the structure
2,2,4-trimethylpentane has been accepted for
treatment in admixture with the normal heptane,
further subjecting the 90-92° C. fraction in a
second step to contact with metal halide
hydrogen halide catalysts at a lower temperature
to produce substantial yields of dimethylpentanes,
,
fractionating the products from the second step
to produce a fraction boiling from about 75 to
about 90° C. and comprising said dimethyl
'
pentanes, and a higher boiling fraction which
10 is recycled to further isomerization, subjecting
the 75-90° C. fraction in a third step to contact
with metal halide-hydrogen halide catalyst to ‘
effect furtherisomerization of said pentanes and
fractionating the products from a third step
or hydrocarbon mixtures in respect to their anti .15 to recover a fraction boiling between about '19
knock value when used as fuel in standard test
and about 81° C. comprising 2,2-dimethyipentane,
some time as a standard for rating hydrocarbons
engines. In contrast to the antiknock value of
2,4-dimethy1pentane and 2,2,3-trlmethylhutane,
this compound which is usually rated as 100, the
while recycling higher boiling materials to fm'ther
antiknock value of normal heptane is placed as
isomerization treatment.
0, so that these two hydrocarbons represent the 20 In accordance with the. principles of the present
limits of an arbitrary scale of values employed
invention the isomerization of normal heptane
in evaluating the antiknock properties of hydro
is accomplished progressively in a series of steps
carbons.
in which conditions of isomerization are modi?ed
Itis known in the artlthat substantial yields
to favor equilibria corresponding to the produc
of branched isomers can be produced from nor 25 tion of the most highly branched isomer triptane.
mal para?ln hydrocarbons by contacting the lat
Thus,‘ the temperatures employed in the succes
ter with catalysts oi‘ the Friedel-Crafts type, par- .
sive steps are progressively decreased. In the
ticularly such compounds as aluminum chloride, .
?rst step in which normal heptane undergoes
aluminum bromide, zirconium chloride, zinc chlo
primary isomerizatiori into methyl hexanes and
ride, ferric chloride and others in the presence 30 ethyl pentanes, temperatures of from about ll to
of hydrogen halides such as hydrogen chloride
about 75° C. may be employed depending upon
01' hydrogen bromide. In e?ecting such isomer
the activity of the metal halide-hydrogen halide
izations it has been found that anlequilibrium
catalysts used for effecting isomeriaatiom In
between the possible isomers is usually reached
this step pure aluminum chloride or aluminum .
under the .conditions of operation depending 35 bromide may be used along with substantial;
principally upon the factors 01' temperature and
amounts of hydrogen chloride or hydrogen
time of contact with a selected catalyst, although
bromide and in order to produce maximum
other factors such as the presence of varying
amounts of the methyl hexanes and ethyl
amounts of hydrogen halides and hydrogen may
pentanes, the time of contact with the composite
influence the equilibrium actually attained. In 40 isomerizing catalyst is keptrelatively short, and
the present process use is made of the equilibria
emphasis is placed on a relatively high recycle
attained in the step-wise isomerization 0! normal‘
rate of unconverted normal heptane to insure
Dara?lns to e?'ect - a degree or isomerization
'high yields of the desired primary isomerization
hitherto unattained in such processes.
In one speci?c embodiment the present inven 45 products. Following the primary isomer-isms
step; the products are fractionated to recover an
tion comprises a process for the manufacture of
triptane from normal heptane which consists in ' isomer fraction boiling ‘from about 90 to about
92° C. which consists largely of methyl hexane‘,
subjecting said normal heptane to‘ contact with
using fractionators or capacity adequate for e!
a metal halide-hydrogen halide catalyst in the
primary stage to effect a limited isomerization 50 fecting a relatively sharp separation of this cut.
The boiling point of 2-methyl hexane at "180 mm.
with the production of methyl hexanes and ethyl
pressure is 90.1° C. and that 01' B-metiwl hexane
pentanes, iractionating the products to produce
a cut boiling from about 90 to about 92° 0. com
, is 91.9“ c. so that theta-92° 0. cut will conskt
P 'ising said hexanes and said pentanes, and
largely of these two compounds and the recycled
heavier iractions which are recycled to further. 55 materialwhichis returnedtoturtherisomerillng
2,402,807
3
4
treatment will consist principally of unconverted
normal heptane and some ethyl pentanes.
In the foregoing paragraphs a description has
been given of the essentia1 steps of the present
In the second step of the process the methyl
hexane fraction boiling from about 30 to about
92° C. is further isomerized to produce a mix
ture of 'dimethyl pentanes. In this step the
temperature employed is lower than that em
ployed for the primary step and will be some
where within the range of —25 to 50° C., depend
process without regard to non-essential details
of the operation. In this respect each of the
successive steps may be carried out in any de
sired manner to accomplish the stepwise pro
duction of isomers with an increased degree of
' hydrocarbon chain branching. —Thus, the steps
may be conducted in batch operation by merely'
ing again on the activity of the catalyst andthe 10 charging the material to be isomerized into re-v
action vessels capable of withstanding pressure
amount of hydrogen halide used. In general,
the conditions employed in the second step will
be modi?ed in the direction of decreased isomer
izing activity, and in this step in order to avoid
undesirable side reactions involving decomposi
tion rather than isomerization of the hydrocar
bons, hydrogen may be introduced to the isom
erizing zone in molecular form or it may be gen
along with the catalyst and added hydrogen and
the reactants subjected to heating for a limited
period of time after which the reaction products
15 are fractionated, although such operations are
not favored since they do not permit the use of
the preferred short times of reaction correspond- '
ingto limited conversions.
erated in situ by interaction of added hydrogen
Continuous operations may be conducted by
chloride with metals in admixture with the metal 20 passing the hydrocarbon mixtures charged to
each step along with hydrogen chloride and, if
halide. Similarly, instead of using aluminum
desired, hydrogen through stationary beds of
chloride in the second step, its action may be’
modi?ed by the presence of other metal halides
granular metal halides followed by continuous
fractionation with recovery of the desired cuts
such as, zinc chloride, zirconium chloride or fer
ric chloride. Again, contact times are preferably 25 for further isomerization, such operations‘ in
short to favor the production of the dimethylpen
volving the‘ use of alternate reaction and frac
tanes as the principal products of the secondary
tionation zones with passage of the primary
isomer fractions to succeeding stages and re
step. After the isomerization has been effected
‘ to the desired degree, the dimethylpentanes are
cycle of hydrogen chloride and unconverted hy- '
recovered by separating a fraction boiling within 30 drocarbon fractions back to preceding stages.
Granular catalysts used in this type of operation
the approximate range of 75 to 90° C. by the use
of fractionating apparatus of suitable design and
may consist of particles of the metal halides
capacity. Boiling points of the dimethylpentanes
themselves or particles consisting of granules
of relatively inert supporting materials to which
are given below:
35 the metal halide has been added by any suitable
method. Examples‘ of such catalyst supports are
Dimcthylpentane
1:131:11‘?
such substances as activated carbon, prepared
aluminum oxides, bauxite, clays, kieselguhr and
.
° C.
other more or less refractory materials having
40 varying absorptive capacities.
2,2dimethylpcntanc. .
2,4-dimethylpe tone. _
79. 2
80. 7
3,3~dimethylpentane _ .
86. 0
Another type .of continuous operation which
2,3-dimethylpentanc ___________________________________ . _
89. 8
may be employed in any one or all of the three
The hydrocarbon fraction boiling above 90° C.
_
steps of the process consists in passing the hydro
carbon or hydrocarbon mixture to be isomerized
is recycled either to the recycle primary step or 45 through 'a bed of granular metal halide in the
absence of a hydrogen halide under conditions
to the secondary step for further isomerizing
of temperature and pressure at'which the hydro
carbon mixture dissolves the metal halide, and
In the third step of the process the recovered
passing solution of metal halide and hydrocarbon
dimethylpentanefraction boiling from about 75
to about 90° C. is further contacted with metal 50 along with added hydrogen halide into a reactor
packed with granular materials which are gen
halide-hydrogen halide catalysts at still lower
erally inert and have varying absorptive capaci
temperatures, preferably below —35" C. and the
treatment.
‘
-
ties for the metal halide dissolved in the hydro
carbon. In such processes the dissolved metal
and hydrogen halide is proportioned to favor
the production of the more highly branched 55 halide is deposited upon the granules in the re
actor and isomerization ensues in the presence
isomers without fostering decomposition reac
catalyst composite consisting of the metal halide
of the added hydrogen halide. In this scheme
of operations fresh surfaces'of metal halide are
continually exposed so that catalytic activity in
tion in respect to temperature, catalytic activ
ity, contact time, etc., substantial yields of the 80 the packed reactor is maintained over extended
tions. In this third and ?nal stage of the proc- '
css, under suitably chosen conditions of opera
desired triptane are produced and by fractionat
ing to produce a ‘IQ-81° C. fraction from the hy
drocarbon products, a mixture consisting of 2,2,
and 2,4-dimethylpentanes and 2,2,3-trimethyl
periods of time while metal halide-hydrocarbon
complexes may 'flow downwardly to be removed
at the bottom of the packed reactor, or are ab
sorbed in the pores of the granular material.
butane is recovered. The normal boiling points 65
Other types of isomerization procedures which
of the dimethlypentanes have been given above.
may be used in the steps of the process include
The normal boiling point of the desired triptane
those in which a stream ‘of the vapors of the
hydrocarbons tobe isomerized carries powdered
is 80.9° C., and it is, therefore di?icultly sepaq
‘table from the 2,4-dimethylpentane. However,
‘metal halide catalyst upwardly through a reac
as will be shown in later examples, it is pro
tion chamber to which hydrogen chloride or
hydrogen halidev is added to e?ect the-desired
.duclble in substantial"concentrations in admix- ~
ture with the dimethyl pentanes to form hydro
isomerization, the powdered metal halide being
carbon mixtures or exceptionally high antlknock r‘ separated in a succeeding chamber, subjected to
Value.
~
‘
‘u any reactivation steps which are necessary to
2,402,807
,
5
6
.
presence of a hydrogen halide to contact with a
metal halide catalyst in a. primary stage under
restore its activity and then returned to further
contact with incoming hydrocarbon vapors.
.
‘ The following example'is introduced to illus
conditions adequate to produce substantial yields
of methyl hexanes, separating said methyl
trate the results which are normally'obtainable
hexanes and subjecting them in a secondary
stage to contact with a metal halide catalyst in
the presence of a hydrogen halide under condi
tions adequate to produce substantial yields of di
in the use of the process although the scope of ‘
theinvention is ‘not intended to be limited in
exact accordance therewith.
Normal heptane is subjected to isomerization
by passing it at a temperature of 75° C. upwardly
through a granular catalyst bed containing gran
ular composite material consisting of 80 per cent
by weight of activated alumina and 20 per cent
‘tones and subjecting them in the presence of a
hydrogen halide in a tertiary stage to contact
with a metal halide catalyst under conditions
by weight of aluminum chloride. Five mole per
adequate to produce substantial yields of triptane.
methylpentanes, separating said dimethylpen
2. A process for the isomerization of normal
15 heptane to produce triptane therefrom which
cent of hydrogen chloride in respect to the nor
mal heptane is admitted along with the hydro
carbon.
comprises subjecting said normal heptane in the
The hydrocarbon products from the
presence of a hydrogen halide to contact at a
temperature of from about 0 to about 75° C. with
a metal halide catalyst in a primary stage to pro
lsomerizing step are fractionated to remove prod
ucts boiling below 90° .C. and recover the hydro
carbon fraction boiling from 90 to 92° C. com
prising principally Z-methyl and 3-methyl hex 20 duce substantial yields of methyl hexanes, sepa
rating said methyl hexanes and subjecting them
ane. The products boiling below 90° C. are fur
in the presence of a hydrogen halide in a sec
ther fractionated to recover hydrogen chloride
ondary stage to contact at a temperature of from
which is recycled to mix with the normal heptane
about —25 to about +50° C. with a metal halide
charge and a fraction boiling above 92° C. and
comprising 85 per cent normal heptane is re 25 catalyst to produce substantial yields of dimethyl
pentanes, separating said dimethylpentanes and
cycled to further contact with the granular cata
subjecting them in the presence of a hydrogen
lyst. The"90-92° C. fraction continuously pro
halide in a tertiary stage to contact at a tem
duced with recycling of unconverted material is
perature below —35° C. with a metal halide cata- ‘
equal to 70 per cent by volume of the normal
lyst to produce substantial yields of triptane.
heptane charge.
' The 90-9,2° C. fraction is contacted with another I
3‘. A process for the isomerization of normal ‘
heptane to produce triptane therefrom which
stationary bed of the same type of catalyst em
- comprises subjecting said normal heptane in the
ployed in the first step at a temperature of 0° C.
,presence of a hydrogen halide to contact at a
in the presence of 5 mole per cent of hydrogen
‘chloride based on the mixture‘of methyl hexanes 35 temperature of from about 0‘to about 75° C. with
a metal halide catalyst in a primary stage, frac~
charged. The products from the second step are
tionating the products from said primary stage
fractionated to produce hydrogen chloride which
into hydrogen halide, hydrocarbons boiling below
is recycled in the same step, a 60 volume per cent
90° C., a hydrocarbon fraction boiling from about
yield of a hydrocarbon fraction boiling from 75
to 90° C. and a heavier fraction boiling above 40 90 to about 92° C. and a higher-boiling hydro
carbon fraction, returning said hydrogen halide
and said higher-boiling hydrocarbon fractions to
further contact with said metal halide catalyst
dergo further isomerization in admixture with
in the primary stage, removing hydrocarbons
the methyl hexane fraction. ‘
'
The 75~90° C. fraction comprising dimethyl 45 boiling below 90° C., subjecting said fraction boil
ing between about 90. and about 92° C. in the
pentanes is now contacted with a granular com- ~
, presence of a hydrogen halide to contact at a tem
posite catalyst consisting of activated alumina
perature of from about —25 to about +50° C.
supporting an equimolar mixture of aluminum
with a metal halide catalyst in a secondary stage,
chloride and aluminum bromide at a tempera
ture of —40° C.,. the liquid hourly space velocity 50 fractionating the products from said secondary
90° C. and containing ethyl pentanes. The last
named fraction is continuously recycled to un
of the hydrocarbon mixture in respect to the
volume of catalyst being 0.05.
The eiiluent materials from this catalytic con~
tact are continuously fractionated to separate
the added hydrogen halides for recycling, and 55
to produce a 50 per cent yield of a '79-8l° C. frac
tion and higher boiling products which are re
cycled to further isomerizing treatment in ad
mixture with the dimethylpentanes. Analysis of
stage‘to produce hydrogen halide, compounds
boiling below 75° C., a fraction boiling from about
75 to about 90° C., and a higher-boiling hydro
carbon fraction, returning said hydrogen halide
and said higher-boiling hydrocarbon fraction to
further treatment in said secondary stage, sub
jecting said fraction boiling from about 75 to
about 90°C. in the presence of a hydrogen halide
to contact at a temperature below -35° C. with a v
the 79-81° C. fraction indicates the presence of 60 metal halide catalyst in a tertiary stage, frac
tionating to produce hydrogen halide, compounds
60 per cent of a mixture of 2,2 and 2,4-dimethyl
boiling below ‘79° 0., a hydrocarbon fraction boil
pentanes and 40 per cent of 2,2,3-trimethylbu
ing from about 79 to about 81° C. and a higher
time. The octane number of this fraction is found
boiling hydrocarbon fraction, removing said com
to be 95 in comparison with a standard 2,2,4
trimethylpentane.
4
v
'
By the above described operation there is thus
continuously produced a 21 per cent overall yield
of 95 octane number hydrocarbon material based
on the normal heptane charge, the yield of trip
tane being-8 per cent by volume based on the 70
heptane charged.
“
‘
Iclaim asmy invention: ‘
pounds boiling below '79? (2., returning said hy
drogen halide and said higher-boiling hydrocar
bon fraction to further treatment in said tertiary
state and recovering said fraction boiling from
about 79 to about 81° C.
‘
4. A process for the isomerization of normal
heptane ‘to produce triptane therefrom which
comprises subjecting said normal heptane in the
1. A process for the isomerization oi.’ normal
presence of hydrogen chloride to contact with r1
heptane to produce triptane therefrom-which
aluminum chloride catalyst in a primary stage
comprises subjecting said normal heptane in the 75 under conditions adequate to produce substantial
2,402,807
7 .
yields of methyl hexanes, separating said methyl‘
higher~boiling hydrocarbon traction, returning
hexanes and subjecting them in the presence of
hydrogen chloride in a secondary stage to contact
with an aluminum chloride catalyst under condi
said hydrogen chloride and said higher boiling
hydrocarbon fraction to further treatment in said
tertiary stage and recovering said traction boil
ing from about '79 to about 81°_ C.
‘ tions adequate to produce substantial yields oi
dimethylpentanes, separating said dimethylpent
7. A process for the treatment of normal hep
anes and subjecting them in the presence oi.’ hy
tane to produce isomeric heptanes therefrom
drogen chloride in a'tertiary stage to contact with
which comprises subjecting said normal heptane
an aluminum chloride catalyst under conditions
in the presence or a hydrogen halide to contact
adequate to produce substantial yields of trip 10 with a metal halide catalyst in a primary stage
tane.
under conditions adequate to produce substan
5. A process for the isomerization of normal
tial yields of methyl hexanes, separating said
heptane to produce triptane therefrom which
comprises subjecting said normal heptane in the
methyl hexanes and subjecting them in a sec
ondary stage to contact with a metal halide cata
presence of hydrogen chloride to contact at a 15 lyst in the presence 01 a hydrogen halide under
temperature of from about 0 to about ‘75° C. with
conditions adequate to produce substantial yields
an aluminum chloride catalyst in a primary stage
of dimethylpentanes, separating said dimethyl
to produce substantial yields of methyl h'exanes,
pentanes and subjecting them in the presence of
separating said methyl hexanes and subjecting
a hydrogen halide in a tertiary stage to contact
them‘ in the presence of hydrogen chloride in a 20. with a metal halide catalyst under conditions
secondary stage to contact at a temperature of
adequate to produce substantial yields of other
isomeric heptanes.
from about --25 to about +50“ C.- with an alu
minum chloride catalyst to produce substantial
8. A process for the treatment of normal hep
yields of dimethylpentanes, separating said di
tane to produce branched chain hydrocarbons
methylpentanes'and subjecting them ‘in the pres
therefrom which comprises subjecting said nor
ence of hydrogen chloride in a tertiary stage to 25 mal heptane in the presence of hydrogen chlo
contact at a temperature below —35° C. with an
ride to contact at a temperature of from about
aluminum chloride catalyst to produce substan
0 to about 75° C. with an aluminum chloride
tial yields of triptane.
v catalyst in a primary stage to produce substan
6.‘ A process for the isomerization of normal
tial yields of methyl hexanes, separating said
comprises subjecting said normal heptane in ad
mixture with hydrogen chloride tocontact at ya
vtemperature of from about 0 to about 75° C. with
ence of hydrogen chloride in a secondary stage to
contact at a temperature of from about —25 to
heptane to produce triptane therefrom which 30 methyl hexanes and subjecting them in the pres
about +50° C. with an aluminum chloride cata
an aluminum chloride catalyst in a primary
35 lyst to produce substantial yields of dimethyl
- stage, iractionating the products from said pri
pentanes, separating said dimethylpentanes and
mary stage to produce hydrogen chloride, hydro
subjecting them in the presence of hydrogen chlo
ride in a tertiary stage to contact at a tempera
ture below ~35° C. with 'an aluminum chloride
carbons boiling below 90° C., a hydrocarbon frac
tion boiling from about 90 to about 92° C. and
'ahigher-boilin-g hydrocarbon fraction, returning
40
said hydrogen chloride and said higher-boiling
hydrocarbon fraction to further contact with said
aluminum chloride catalyst in said primary stage,
removing hydrocarbons boiling below 90° (3., sub
jecting said fraction boiling between about 90 45
catalyst.
‘
.
9. A process for producing triptane which com
prises isomerizing normal heptane under condi
tions regulated to produce methyl hexanes and
ethyl pentanes therefrom, separating from the
resultant products a fraction boiling from about
and about 92° C. in admixture with hydrogen ‘ '90“ C. to aboutv 92° C., subjecting said fraction
chloride to contact at a temperature of from“
about —25 to about +50° C. with an aluminum
to controlled isomerization to produce dimethyl
pentanes therefrom, separating-from the prod
chloride catalyst in a‘ secondary stage, fraction
ucts of the last-mentioned step a fraction boiling
ating the products from said secondary stage to 50 from about 75° C. to about 90° C., and subjecting
produce hydrogen chloride, compounds boiling
the last-named fraction to 'isomerizin'g conditions
below 75° C., a fraction boiling from about 75
regulated to convert a portion thereof into 2,2,3
to about 90° C., and a higher-boiling hydrocarbon ~
trimethylbutane.
,
w
traction, returning said hydrogen chloride and
10. A process for producing triptane which
said higher-boiling hydrocarbon fraction to fur 55 comprises subjecting a mixture of dimethylpen
ther treatment in said secondary stage, subjecting
tanes to the action of an isomerizing catalyst at
said traction boiling from about 75 to about 90°
an isomerizing temperature below —35° C.
C. in admixture with hydrogen chloride to con
11. A process for producing triptane which
tact at a temperature below -35° C. with an
comprises subjecting a mixture of dimethylpen
aluminum chloride catalyst in a tertiary stage, 60 tanes to the action of an aluminum halide and a
Iractionating to produce hydrogen chloride, com
pounds boiling below '19"v C., a hydrocarbon trace
tlon boiling from about '79 to about 81° C. and a
hydrogen halide at an isomerizing temperature
below -35° C.
'
‘
\
'
GUSTAV EGLOFF.
_
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