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Патент USA US2411817

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NOV. 26, 1946'
Filed sept. .'50,l 194:5
'Patented Novias, 194e
Ralph B. Thompson and Joseph A. Chenicek,
Riverside, Ill., assignors to Universal Oil Prod
ucts Company, Chicago, lll., a corporation of
Application September 30, 1943. Serial No. 504,462
10 Claims.y (Cl. Zim-683.4)
This invention relates to the alkylation of isoparailins with oleilns in the presence ofan aluminum chloride catalyst. The invention is more
speciilcally concerned with certain improvements
in the production of valuable hexanes by the al- 5
kylation of isobutane with ethylene.
It is known that valuable hexanes'can be pro-
to the alkylation zone. Therefore, ethyl chloride
lcan be recycled indeiinitelyv in the system with
the addition of relatively small amounts of make
up hydrogen'chlorlde to compensate for mechani
cal losses, etc.
In- a broad aspect the present invention relates ,
_ to the use of ethyl chloride as a promoter for
duced by the interaction of isobutane with eth-
aluminum chloride catalysts in the alkylation of
isobutane with ethylene.
When this alkylation is conducted in the
presence of a suitable catalyst, e. g., aluminum 10 'In one specific embodiment the present înven-~v
chloride or- an aluminum chloride-hydrocarbon ' tion comprises alkylatlng isobutane with ethylene
complex, 2,3-dimethylbutane is obtained as the '
in the presence of an aluminum chloride cata
principal alkylation product. This hydrocarbon , ' lyst and ethyl chloride-as a promoter, separating
has veryy valuable antiknock properties and is,
ethyl chloride from the reaction products, recover
therefore,` desired for use in aviation gasoline 15 ing alkylation products of desired boiling range,
blends or other motor fuels. It is generally deand recycling said Separated ethyl chloride to the
slrable'to employ hydrogen chloride as a pro-
moter for the aluminum chloride or aluminum
chloride-hydrocarbon complex catalyst.
alkylation step.
'I'he term aluminum chloride catalyst as used
in this speciñcation and appended claims is in
From a commercial point of view, the isobu-` 20 tended to include aluminum chloride vper se, alu->
tane-ethylene alkylation process employing an
mlnum chloride supported on various relatively
aluminum chloride catalyst presents a diilicult
problem. >Since ethylene is not readily available
inert carriers, aluminum chloride composited with
other. lcatalytic materials such as other metal
in pure’form. it is necessary to employ ethanehalides, and . aluminum chloride-hydrocarbon
' ethylene fractions as a source of ethylene feed. 25 complexes. The preferred method of utilizing
These Cn hydrocarbon fractions as produced in
various hydrocarbon. conversion processes, e. g.
‘ thermal or catalytic cracking, may contain from
about 30 to about 70 mol per cent of ethylene.
aluminum chloride to catalyze the reaction of iso
butane with ethylene is in the form of a fluid
aluminum chloride-hydrocarbon complex.'` Vari
ous complexes may be prepared lby contacting ole
If this mixture is charged directly to the alkyla- 30 ilns, aromatics, naphthenes, parailins, or mix‘
tion zone, a gaseous fraction is separated from the
tures thereof with aluminum chloride under suit
alkylation products which comprises unconverted
ethane and hydrogen chloride. The separation
of hydrogen chloride from ethane in order to
permit recycling ofthe catalyst promoter to the 35
able reaction conditions and preferably in the
presence of hydrogen chloride. It will be appar
ent that a wide variety of complex catalysts may
be Prepared dependent upon the particular hy
alkylation zone is a relatively inconvenient and
drocarbons chosen to react with the aluminumy
costly procedure. In order. to avoid this difliculty it has hitherto been customary to provide
chloride, the relative amounts of reactants, the
reaction conditions, etc. In general we prefer
an ethylene concentration unit which by means
to employ an aluminum chloride-hydrocarbon
of aseries of fractionation steps increases the con- 40 complex of the type which is formed inherently
centration of ethylene in the ethane-ethylene
when isobutane and ethylene are contacted with
feed to the order of 85-95 mol per cent thereby
aluminum chloride under alkylating conditions.
decreasing the quantity of ethane charged to the
.The nature of our preferred catalyst will be de
alkylation system and minimizing the ethane-
scribed hereinafter in greater detail.
hydrogen chloride separation problem.
' 45 For further explanation ~oi.’ the present inven-a
We have discovered that under suitable contion reference is now made to the drawing Where
ditions substantially all of the hydrogen chloride
' in Figure vl is a diagrammatic flow chart of the
charged to the alkylation system reacts with ethylene to produce ethyl chloride. The separation
process of the present invention and Figure 2`
illustrates in detail the preferred arrangement
`of the latter compound from unconverted ethane 50 of apparatus for conducting the alkylation step
is asimple matter, and the ethyl chloride may « in the presence ofapreferred'catalyst.
be recycled to the alkylation zone thereby replac- `
, ing hydrogen chloride as a promoter. We have
Referring to Figure l, zone I represents an
allwlation zone of any suitable typeior effecting
found that, contrary to expectation, there is >no
the isobutane-ethylene alkylation in the presence
net consumption of the ethyl chloride recycled 55 of an aluminum‘chloride catalyst.~ lIi.' the catalyst
ported aluminum chloride, reaction zone l will
usually consist of a fixed bed oi' the solid catalyst
lthrough which the reactants are passed under
alkylatlon conditions of temperature, pressure,
space velocity, etc. If the catalyst consists of a
iiuid aluminum chloride-hydrocarbon complex,
reaction zone I will comprise suitable equipment
steps, etc.
As an alternative method of operation all or a
yportion of the normal butane-ethyl chloride
for eiïecting alkylation reactions in the presence
of a liquid alkylating catalyst, e. g. a mechanical
azeotrope may be recycled directlythrough line
22’ and valve 23’ to line 6 and thence into alkyl
ly agitated reaction zone, jet mixer, "time tank"
provided with internal baiiles and/or orifices, etc.
ation zone I. This operation may be feasible
4when the normal butane content of the butane
An isobutane fraction which, ordinarily con
tains appreciable quantities of normal butane is
charged to the alkylation zone through line 2 and
valve 3.
withdrawn through line 25 and valve 28. By thus
recycling ethyl chloride to the alkylation zone I
it will only be necessary to add relatively minor
amounts of make-up hydrogen chloride through
line 6 in order to compensation for mechanical
losses, certain ineiliciencies in the separation
comprises granular aluminum chlorideor sup
feed introduced to the system .through line 2 is
‘relatively low, but it will generally be necessary to
An ethane-ethylene fraction is admitted '
-remove at least a portion of the normal butane
through line 4 containing valve 5. Hydrogen
from the system by means of separation step 24,
type can readily be supplied through line 6 with
out the disadvantages previously expected from
such a method of operation. 'I'he reaction prod
particularly convenient consists in treating the
or merely by withdrawing a portion of the
chloride may be introduced to alkylation zone I
azeotrope from the system throughline 29 and
through line 6 and valve 1. In the isomerization
of normal butane in the presence of AlCla-HCl 20 valve 29’.
'.Various methods may be employed in separa
it is often necessary to discard an ethane
tion step 24 for resolving the normal butane
hydrogen chloride mixture. In the present in
ethyl chloride azeotrope. One method which is l
vention, however, an ethane-HC1 mixture of this
azeotrope with a selective solvent in which the
ethyl chloride is preferentially soluble. In gen
eral, polar solvents that are insoluble in butane
may be employed in the extraction step. The
ethyl chloride may then be recovered from the
ucts are withdrawn from the- reaction portion of
the system and are introduced through line 8
containing valve 9 to separation zone III which
will ordinarily comprise one or more fractionating 30 solvent by distillation. Suitable polar solvents
comprise the alcohols such as methyl alcohol,
zones eûuipped with the conventional condensers,
ethyl alcohol, isopropyl alcohol, or mixtures
receivers, etc. Unconverted ethane is withdrawn
thereof. Polyhydroxy alcohols such as ethylene
as a gas through line II containing valve I2 and
glycol or propylene glycol arealso suitable. Ex
is vented to the atmosphere. In certain cases
- cellent results are also obtainable using aqueous
this discarded ethane fraction may contain rela
solutions of the alcohols, particularly ethyl al
tively minor amounts of hydrogen chloride. Un
coverted isobutane is withdrawn from zone I0
and recycled through line I3 and valve I4 to
As another possible method of separating >
ethyl chloride, the azeotrope may be contacted
with a dehydrohalogenating catalyst whereby to
line 2 and thence into alkylation zone I. Alkyl
ation products are withdrawn through line I6 40 decompose the ethyl chloride to ethylene -and hy
drogen chloride. The ethylene -and hydrogen
containing valve I6 and are subjected to frac
chloride are separated from normal butane and
tionation in zone I1. A lower boiling fraction
may be recycled directly to the alkylation zone
comprising 2,3-dimethylbutane is recovered
or if desired may be recombined in the presence
through line> I8 and valve I9. Higher boiling
of a suitable hydrohalogenation catalyst to form
alkylation products such` as- octanes are with
ethyl chloride which is then returned to the al
drawn through line 20 containing valve 2|.
-lrylation step.
As hereinbefore described, we have found that
In starting up an alkylation process of the
the hydrogenl chloride charged to alkylation zone
I is substantially completely converted to ethyl
chloride by reaction with a portion of the ethylene
feed. vSince ethyl' chloride has a normal boiling
point of 12.2°C., it may be condensed readily and
the unconverted ethane may be vented from the
present type two general methods of operation
may be employed. Obviously, it is possible to
charge ethyl chloride directly to the alkylation
zone as a promoter for the aluminum chloride
the necessity of recycling excessive amounts of
catalyst and when the system contains sufñcient
ethyl chloride, the addition of make-up hydrogen
chloride'may be started. In another method of
operation, only hydrogen chloride is charged to
the system initially. As the alkylation reaction
proceeds the hydrogenv chloride added is almost
completely converted to ethyl chloride which is
contains approximately 12-13 mol per cent ethyl
Zone 35 is a pickup or saturation zone which con
a gas.
Ethyl chloride forms
azeotrope with .normal butane, however, and in
some cases it will _be necessary to recover ethyl
chloride from the azeotropic mixture in order
to recycle the same to the alkylatlon step without
normal butane. We have not observed any in 60 recovered in the manner hereinbefore described
and recycled to the alkylation step.
dications that an azeotrope is formed between iso
Figure 2 illustrates a preferred arrangement of
butane and ethyl chloride. At atmospheric pres
apparatus for eiîecting the alkylation reaction.
sure the normal butane-ethyl chloride azeotrope
chloride and has a boiling point almost -identical
with. that of pure normal butane.
The normal butane-ethyl chloride azeotrope
may be withdrawn from the. separation step
through line 22 containing valve 23 and intro
duced into`a separation zone 24 wherein the ethyl
chloride is separated from _the normal butane by
some suitablemeans other'than by distillation.
The separated ethyl chloride is recycled to the
alkylation -zone through line 21 containing valve
28 and thence through line 6. Normal butane is
tains a bulk supply of aluminum chloride usually
in the form of granular particles. The isobutane
charge is introduced at least in part through line
30 containing valve 3|, pump 32, and line 33 con
_taining valve 34 to the pickup zone 35. This por
tion of the isobutane charge dissolves aluminum
chloride during its passage through zone 35 and
the eiiluent stream removed through line 36 and
valve 31 is substantially saturated with aluminum
chloride. Another portion of the isobutane
charge is passed through line 38 and valve 39 and
is commingled with the edluent solution from
time (defined as volume of catalyst in the reac- l
tion zone divided by the volume rate per minute
zone 35 as shown. The mixture is charged to
alkylation zone I0. If ldesired all of the isobutane
charge may pass through zone 35.
of hydrocarbon feed) of 28 minutes was employed
at a temperature of 140° F. and a pressure of 250
The ethane-ethylene charge is introduced to CTI poundsper square inch gage. The pickup Ízone
alkylation-zone 40 through line'43 containing
valve M. Hydrogen chloride and recycled ethyl-
was operated at 150° F. and 250 pounds -per square inch 888e.
chloride are added through'llnerlä containing
valve 46. Alkylation zone l0 is a mechanically
agitated zone provided with' stirring device.“
driven by motor 42. During- the alkylation- reac
During this operation a yield of `hexanes of 193
- weight per centgbased on the ethylene charged
was obtained. The hexane cut had a chlorine
content of 0.0002 weight per cent. l
.tion in zone 40 the> fresh aluminum chloride in
In an attempt to obtain a weight balance on
troduced from pickup zone-35 is converted to a
the hydrogen chloride charged to the systeml the
~ iluid aluminum chloride-hydrocarbon complex.
ei'iluent gas from the stabilization step was
scrubbed with a measured volume of sodium hy
droxide and the excess base titrated with lhydro
chloric acid. In three such determinations made
The eilluent mixture of catalyst andreactionf
products is passed through line 4l and valve I8
' _ to settler 49 from which an upper hydrocarbon
layer is withdrawn to further separation >steps
during the .run ’ the hydrogen chloride in the
through line 50 containing valve 5I and a lower
emuent gas was found to beonly 0.01-0.02 'gram> '
catalyst ,layer is recycled to the alkylation zone 20 per hour whereas the rate of introduction >of
through line 52 containing valve 53. pump 50, and
hydrogen chloride to the alkylation system was
line 55 Acontaining valve 56. .A portion of the
approximately 1.8 grams per hour. From these
used catalyst may be withdrawn from the system
results it is apparent that most of the hydrogen
through line 51 containing valve 58.
chloride was converted- to organic chlorine con’
taining compounds during the alkylation re
' In the system described in connection with
Figure 2 it will be apparent that the aluminum
chloride content ofthe aluminum chloride-hy
Example II
drocarbon complex catalyst in alkylation zone v40
may be ‘controlled accurately by the addition of '
. In a further attempt to explain the apparent
regulated amounts of aluminum chloride from 30 consumption of hydrogen chloride observed in
pickup zone 35. The amount of aluminum chlo
Example I similar alkylation runs were made and
ride carried over from Yzone 35 is dependent upon
the 'distribution of chlorine was. determined in
the proportion of isobutane charge passed
the various products. rThe results of the chlo
through the zone and also upon the temperature
rine determinations are summarized as follows:
therein.A For optimum production of 2,3-dimeth‘
Distribution of chlorine in ethylene-isobutane
ylbutane it is desirable to maintain the aluminum
chloride content of the complex catalyst within
the range of from about 60 to about 85% by
weight based on Ahoy` analysis. The alkylation
reaction may be conducted at temperatures oi ,40,
from about 50°F. to about 170° F., preferably 100’
" F. to 140"~ F., and under suñicient pressure to
maintain at least' a‘ portion of the reactants in
the liquid phase. It is also desirable to -maintain
an appreciable mol excess of isobutane over’eth'
ylene -in the hydrocarbons charged to the alkyla
tion step, e. g.'from~about 4:21 to about 20:1.
The following experimental data are presented
in order to demonstrate the nature ofthe present
invention. It is -by no means intended, however.
Period number
Cl in stabilizer overhead ............ ._grams.. 64.92
2 `
Fl in C. from alkylaie ............... ._do....
Cl in total alkyiate ...................`
2. 78
~ 1.48
..... ._
.... __
'rmalolremvered ___________________
o1 1s
It will be evident that most of the chlorine was
to limit the scope of the invention by the details
of these examples. All of the experimental data
described in these examples were obtained in an
found in the lower boiling compounds removed
overhead during the stabilization step. By
means of a careful low temperature Podbielniak
fractionation, the chlorine in the stabilizer over
head was found to be present as ethyl Chloride.
apparatus substantially of the type showndn Fig
`Further evidence that~ ethyl chloride is formed
ure 2 of the drawing. Suitable stabilization ...
during the reaction was obtained in a series of
runs in which the amount of hydrogen chloride
charged to the process' was varied. As the rate
of introduction of hydrogen chloride was in
equipment was provided _for treatment of the hy- .
drocarbon products withdrawn through line 50.
Example I
During a 48 hour period isobutane was alkyl
atedvwith ethylene in the presence of the alumi
num chloride-hydrocarbon complex formed in
situ. The charging stockv to the alkylation ~zone
had the following compositionA on a mol per cent
` creased the yield of alkylate based on the ethyl
ene charged decreased _thus indicating substan
tial reaction of the hydrogen chloride with ethyl
ene. Yields calculated _on the basis of ethylene
available after-_reaction with hydrogen chloride
were approximately the theoretical yields.
Example III
Per cent
Propane;__» ______________ _'. ...... _e-.e__-
Isobutane _________________ __'-„e ..... __
n-Butane ______ --`_ ____________________ _-
Pentanes _____________ _'___.» ___________ .__
Ethylene ___________ _'_'_-'.'. ___________ _-
Hydrogen chloride ..... __; ________ -,_____
A volume. ratio 'of catalyst to hydrocarbon in the ~
’ alkylation- zoneof 0.88 was maintained. - A space
In order to demonstrate that ethyl chloride '
can be recycled to the alkylation zone and that »
it will serve as a promoter for the aluminum
chloride-hydrocarbon complex catalyst without
net consumption, ‘the following test was made
employing substantially the same apparatus andA
method of operation as described in connection
with ExampleI.
ethane feed Àstock since any ethane present in
The combined feed charged to the alkylation
the feed can be separated from ethyl chloride
after alkylation of the ethylene. The recovery of
ethyl chloride from its azeotrope with normal bu
tane is a relatively simplematter and can gener
ally be accomplished with no more difñculty than
zone had the following mol per cent composition:
Per cent
Propane ..-_-
Isobutane ____________________________ -_
______ -._._' ____________ ___ _____ -_
Pentane _
Ethylene _
Ethyl chloride
the hydrogen chloride-'ethane separation step
_ which was previously considered necessary.
An additional advantage attendant upon the
1.1 10 use of ethyl chloride as a promoter for aluminum
chloride alkylation catalysts, particularly the
The reaction was carried out at a temperature of
140° F.„a pressure of 250 pounds per square inch
aluminum chloride-hydrocarbon complex cata
gage, a space time of 29 minutes, and a catalyst
lysts, is the low corrosion rate. When hydrogen
to hydrocarbon volume ratio of about 0.7. The
' chloride isemployed as a promoter` there is often
pertinent results over 322 hours of operation are
a pronounced tendency toward ~corrosion of re
summarized as follows:
action equipment _dependent upon temperature
of operation and concentration of hydrogen
Period No.
We claim as our invention:
Length of period ______ v„_houl’S..
Cumulative time ________ __do___.
93 -
1 214
1 228
Yield of alkyiate, weight per cent
of C2H4 charged ............. _-
Volume per cent hexanes in al-
kylate ....................... _.
73. 6
77. 4
79. 9
80. 4
product ...................... ._ 0.0022l 0.0014
0. 00l7
Chlorine, weight per cent of Ce
1. An. alkylation process which comprises in
troducing isobutane and 'an ethane-ethylene
fraction to a reaction zone and therein reacting
a substantial portion of the ethylene with iso
.'butane in the presence of an aluminum chloride
25 catalyst, supplying tosaid zone an amount of
hydrogen chloride not substantially in excess or'
that which will react with the remainder- of said
ethylene and therein reacting- substantially all ofI
the hydrogen chloride with ethylene to form
30 ethyl chloride in the reaction zone, removing the
reaction products from said zone and separating
Ethyl chloride weight balance:
CzHßCl charged.. -._grams__ ...... _-
CrHßCl recovered. _ _ __do..__ ...... -_
75. 2
68. 5
l76. 9
i Yields uncertain because of operating difficulties.
The 304 _weight per cent alkylate yields in peri
ethyl chloride from the hydrocarbon alkylate and
the ethane content of said’fraction, and recycling
ods l and 2 is approximately the theoretical yield
thus separated ethyl chloride to the reaction zone,
of 307 weight per cent indicating that all of the
ethylene charged was available for alkylation. 35 the amount of ethyl chloride formed in and re
cycled to said zone being suñiclent to promote
This is in marked contrast to the results obtained
the isobutane alkylating reaction therein.
with hydrogen chloride as a promoter in which
2. An alkylation process which comprises in
case a portion of the ethylene reacts with the
troducing ‘ isobutane and an ethane-ethylene
hydrogen chloride charged and is, therefore, un
40 fraction to a reaction zone and therein reacting
available for alkylation.
a substantial portion of the ethylene with isobu
The calculation of the ethyl chloride. recovered
tane in the presence of an aluminum chloride
catalyst, supplying to said zone an amount of
hydrogen chloride not substantially in excess of
unreacted hydrocarbons. The ethyl chloride
charged to the reaction was calculated from the 45 that which will react with the remainder of said
was based upon the chlorine analysis of the sta
bilizer overhead assuming total recovery of
chlorine analysis of the entering charging stock.
ethylene and therein reacting substantially all
Within the experimental error of the operating
technique and the analytical methods, the data
- ethyl chloride in the reaction zone, removing the
of the hydrogen chloride with ethylene vto form
indicate that there is no appreciable consump
reaction products from said zone and separating
tion of ethyl chloride during the reaction. The
fact that only traces of ethane, if any, are found
in the stabilizer overhead leads to the conclusion
ethyl chloride from the hydrocarbon alkylate .
that consumption of ethyl chloride' by halogen
exchange with isobutane does not occur to any
great extent. It will be apparent that in con
tinuous operation on a commercial scale ethyl
chloride lost by mechanical means, etc. can be
replaced by the addition of a small amount of
and the ethane content of said fraction, recy
cling thus separated ethyl chloride to the reac
tion zone, and regulating the amount of ethyl
chloride recycled and the amount of hydrogen
f chloride introduced to said zone to maintain the
ethyl chloride concentration in the reaction zone
within the range of from about 0.6 to about 2.5
mol percent of the hydrocarbon reactants
charged to said zone.
hydrogen chloride to the system.
3. An alkylation process which comprises in
We have discovered that an ethyl chloride 60 troducing
an ethane-ethylene fraction and a
concentration within the range of from about
heavier fraction containing iso and normal bu
0.6 mol percent to about 2.5 mol percent of the
tanes to a reaction zone and therein reacting a
hydrocarbons charged is required for promoting
substantial portion of the ethylene with isobu
the alkylation of isobutane with ethylene.
tane in the presence of .an aluminum chloride
It will be apparent that the process of our in
vention wherein ethyl chloride is formed in situ
by the reaction of hydrogen chloride with ethyl
ene and is then recycled to the reaction zone >
Where it functions as a promoter results in dras
catalyst, supplying to said >zone an amount of
hydrogen chloride not substantially in excess of
that which will react with the remainder of said
ethylene and therein reacting substantially all
of the hydrogenI chloride with ethylene to form
ethyl chloride in the reaction zone, removing the
reaction products from said zone and separating
tic economies in equipment cost and operating
expenditure in the commercial isobutane
ethyl chloride therefrom in the form of an azeo
ethylene alkylation process. When ethyl chloride
trope with normal butane, and recycling at least
is employed as a promoter it is_not necessary to
provide a concentration system for the ethylene 75 a portion of the ethyl chloride content of said
8. 'I'he process oi claim 1 wherein said. catalyst
consists essentially of an aluminum chloride
azeotrope to the reaction zone. the amount of
ethyl chloride formed in and recycled to said
zone being suñlcient to promote the isobutane
hydrocarbon complex formed by contacting iso
butane and ethylene with aluminum chloride
. alkylating reaction therein.
4. The process as deiìned in claim 3 further C: under alkylating conditions.
9. The process of claim 3 wherein said normal
butane-ethyl chloride azeotrope is extracted
chloride is recycled to the reaction zone as an
with a solvent in which ethyl chloride is prefer
azeotrope with normal butane.
entially soluble and ethyl chloride is subsequently
5. The process as defined in claim 3 further
-characterized in that said portion of the ethyl
separated from the extract and recycled to the
characterized in that said portion of the ethyl
chloride is separated from the normal butane
content of said azeotrope prior to its recycling
to the reaction zone.
6. The process of claim 1 wherein the essential
active ingredient ci' said. catalyst consists of
aluminum chloride.
7. The process of claim 1 wherein said catalyst
consists essentially of. an aluminum chloride
hydrocarbon complex.
reaction zone.
l0. The process of claim 3 wherein said nor
mal butane~ethy1 chloride azeotrope is ei‘rtracted
with an alcohol in which the ethyl chloride is
preferentially soluble and ethyl chloride is sub
sequently separated from the alcoholic extract
by distillation and recycled to the reaction zone.
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