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Патент USA US3078332

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Feb. 19, 1963
D. A. MCCAULAY
3,078,322
ymmRoGlazN FLUORIDE ALKYLATION PRooEss
Filed March a, 1961
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3,078,322
~3,078,322
Patented Feb. 19, 1963
conventional bauxite operation. The dried feed is passed
A
,
by way of line 14 and line 16 into reactor 17. Line 16
_.
HYDROGEN FLUÜRIDE ALKYLATION PROCESS
David A. McCaulay, Homewood, Ill., assiguor to Standard
(lil Company, Chicago, lil., a corporation of Indiana
Filed Mar. 3, 1961, Ser. No. 94,216
9 Claims. (Cl. 260----6S3.51)
includes recycled isobutane introduced by way of line 1_8.
Regardless of the type of olefin charged, the mole ratio
of isobutane to olefin is at least about 2. Preferably this
ratio is higher and may be 100 and even more. The
effective isobutane/olefin ratio within reactor 17 may be
far in excess of 2 and may approach 10100 or more by
A This invention relates to the hydrogen ñuoride catalyzed
multi-point olefin injection. In order to distinguish the
alkylation process reacting isobutane with propylene,
10 overall isobutane/ olefin ratio from the ratio actually
butene, and/ or pentene.
present within the reactor, the «overall ratio Vis normally
The octane race has reached the stage where the once
designated as the external I/ O. Thus herein the external
upon a time high octane gasoline components are not any
I/ O ratio is at least about 2 and typically is about 4-'-10.
longer high enough in octane. Once alkylate from isoReactor 17 herein is shown as a vertical contacting
butane-butene reaction Was used to provide the octane
numbers needed to meet the demand. However, alkylate 15 vessel provided with an agitator (not shown) driven by
motor 19. The alkylation reaction is exothermic and in
as now produced needs improvement. Alkylate is im
order to control temperature Within the reactor cooling
portant to present day gasolines because of its low sensi
water is passed by way of line 21 through heat exchanger
tivitivity i.e. small difference between the ASTM research
22 within reactor 17 and withdrawn by way of line Z3.
and motor octane numbers.
The alkylation of the isobutane With propylene, butene, 20 The reactor efiiuent comprising liquid HF catalyst, alkyl
ate hydrocarbons, and unreacted hydrocarbons is with
drawn by way of line 24 and passed to settler
liquid hydrogen fiuoride catalyst. Efforts to improve the
The temperature maintained Within reactor 17 is broad~
effectiveness of this lprocess have been carried on in the
ly on the order of 30° F.--l30° F. In the process of the
past. In general, these modified processes have attempted
to improve the yield of alkylate hydrocarbons boiling in 25 invention, it is preferred to operate at a temperature of
about 60-80‘ß F. It >has been determined that using the
the gasoline range. One of the procedures for modifying
and/or pentene is practiced on a commercial scale with
the activities of liquid hydrogen fluoride as a- catalyst for
paraffin alkylation is set out in U.S.,Patent No. 2,430,181
granted on November 4, 1‘947, on an application filed
September 29, 1941. In this modification, alkali metal 30
fiuorides are dissolved in the liquid hydrogen fluoride; in
the Working example isobutane and normal butene are
reacted at approximately 100° F. using as the catalyst
98% liquid hydrogen fiuoride containing 11% by weight
based on HF of potassium fluoride.
catalyst hereinafter described that there is no significant
advantage with respect to yield of gasoline range/alkyla'te
hydrocarbon and octane number thereofby operating at
temperatures outside the preferred range.
The alkylation reaction takes place with both the feed
hydrocarbons and the catalyst in the liquid state. Suffi
cient pressure is maintained on reactor 17 to keep both
the feed hydrocarbons and the hydrogen fluoride in the
35
liquid state.
l
rlìhe volume ratio of catalyst in reactor 17 to overall
feed charged by way of line 16 is at least about 0.6.
More typically the volume ratio of catalyst to feed in
reactor 17 is about 1-3. It is possible under sorne situa'
The invention herein comprises a particular continuous
process for the alkylation of isobutane with a-t least one
olefin containing 3-5 carbon atoms utilizing liquid hydro
gen fluoride catalyst modified with alkali metal iiuo’ride 40
tions to want to and to operate with more than three
dissolved therein. Problems arise with the use of these
volumes of catalyst per volume of feed, for example
solid alkali metal fluoride modifiers with respect to the
10: 1.
recovery of the liquid hydrogen fluoride catalyst system
The liquid catalyst contains alkali metal fluoride.
for reuse in a continuous process, which problem are
These solid alkali metal iiuorides are very soluble in
solved in the particular process described herein.
45
The invention is described in connection with the an
nexed figure which forms a part of this specification. It
is to be understood that the process features set out are
‘schematic in nature and many items of .equipment have
been omitted as these can be easily added by those skilled 50
in the art.
The feed to the process of the invention comprises iso
liquid hydrogen fiuoride. At 75° F. it has been observed
that approximately 40 parts by weight of sodium fluoride
(Nal-T) are soluble per 10=O parts by weight of liquid HF.
By the alkali metal iiuorides it is understood the ñuorides
of lithium, sodium, potassium, rubidium and cesiuni. It is
preferred to use either sodium iiuoride or potassium
tiuoride.
In parafiin alkylation using liquid HF catalyst in a re
cycle operation, there is a build-up of HF-soluble hydro
i.e. propylene, butene, and pentene. The feed may con
carbons. These HF-soluble hydrocarbons are common'
tain appreciable amounts of normal butaue and pentane
ly referred to as red oil or polymer. (In a typical come
Yand/or propane; also `other materials normally present in
mercial operation practiced at one refinery, it has been
these low boiling hydrocarbons which do not deactivate
observed that substantially optimum yield and other benethe catalyst. In this illustration, the feed consists almost
fits are obtained at a circulating HF catalyst system con
entirely of isobutane and a mixture of butenes derived
from refinery operations. This B-B feed stream is 60 taining close to 2 parts by weight of red oil per 100l
parts by Weight of liquid HF present.) Red oil forma
passed from source 11 by Way of line 12 into feed drier
tion occurs even when alkali metal fluoride catalyst modi
13.Y It is necessary to control the Water content of the
fiers are present. The following usages of alkali metal
»B-'--‘-B stream in order to avoid dilution of the HF
iiuoride are given on the basis that the liquid HF catalyst
catalyst. The feed drying operation may be any conven
system will contain 1~-2 parts by weight of red oil per
tional procedure but in this instance the feed drier Vis a
butane and at least one olefin containing 3-5 carbon atoms
envases
100 parts by weight of liquid HF. The greatest benefit
from settler 2d by way of line 33 and is passed into
of the presence of the alkali metal iiuoride modifier will
column 34.
be obtained by changing the amounts given hereinafter
by .approximately one part by weight or“ alkali metal
carbon phase is distillatively removed. Column 3d is
fluoride for each change in red oil content in parts by
Weight. For example, when the red oil content of the
circulating liquid HF catalyst system is decreased by one
part by weight then approximately the benefits herein
after set forth will be obtained by increasing the amount
of alkali metal iiuoride present by one part by weight.
However, it is to be understood that red oil has a bad
effect on the yield structure of the alkylate hydrocarbons
and it is usual to operate with a red oil content in the
In column 3d the HF content of the hydro
provided with a reboiler 36. In column 34 an overhead
vapor stream comprising an azeotrope of HF and hydro
carbon is removed by way of line 37, condenser 38 and
line 39 to reflux drum 41.
In reflux drum d1 the HF
and the hydrocarbons separate into two layers. A bot
tom layer of liquid I-IF is removed by way of line 42
and may be passed by way of lines 43 and 29 into re
actor 1'7. Hydrocarbons are returned from column 41
by way of line 4d into an upper part of column 3d to act
as redux.
region of 1-3 weight percent and desirably less than 2
percent.
A bottom stream is withdrawn from column 34 by
(Percent herein means one part per l0() parts 15 way of line 46. This stream contains a small amount of
of liquid HF.)
In general, the liquid HF catalyst system contains dis
solved alkali metal fluoride in an amount on the order
of 1-5 moles per 100 moles of hydrogen iiuoride present.
In the case of sodium fluoride usage, the amount of so
dium fluoride present is about 2-10 parts by weight per
100 parts by weight of hydrogen liuoride present; the
preferred usage of sodium fluoride is about 2-6 parts by
weight per 100 parts by weight of hydrogen fluoride
present.
It is to be understood that the amount of alkali metal
iiuoride present given above represents a compromise be
tween yield of octane (C8) hydrocarbons and octane
chemically bound l‘luorine. For product quality it is
necessary to remove this íluorine and this is done by pass
ing the hydrocarbon stream from line 45 through a bed
of bauxite contained in treater ¿17. Bauxite treater 47 is
20 entirely conventional and is not further described herein.
A hydrocarbon stream virtually free from iiuorine is
withdrawn from treater 47 by way ot line 48 and is
passed into de-isobutanizer 51; this tower 51 is provided
with reboiler 52. A stream comprising propane and
25 lighter hydrocarbons and isobutane is taken overhead
from tower 51 and passed by way of line 5ft- into de
propanizer 56. Tower 56 is provided with reboiler 57.
Propane and lighter hydrocarbons are withdrawn over
number thereof. With sodium fluoride as the modifier
head by way of line 59 and passed to storage or further
and a red oil free liquid HF catalyst, it has been deter 30 treatment, not shown. A bottom stream consisting of
mined that optimum beneñts are obtained for octane
isobutane is withdrawn from tower Se and passed by Way
number improvement at 3-l2%; for heavy alkylate i.e.
of line 13 and line 16 into reactor 17.
A. bottoms stream is withdrawn from de-isobutanizer
C94-, of 3-14%; and of C7 and lower material, 3-8%.
It is to be understood that the above figures are spe
51 and is passed by way of line 61 into de-butanizer
ciiically directed to an alkylation reaction between iso 35 tower 62. Tower 62 is provided with reboiler e3. Nor
butane and butenes, said butenes being in about the pro
mal butane is withdrawn from tower 62, by way of over
portion normally encountered in refinery operation. In
head line 6d and sent to storage, not shown.
general, it is considered that this range of alkali metal
Alkylate product is withdrawn from tower 62 and
ñuoride usage will hold -for reactions wherein the olefin is
passed by way of line 67 into bauxite treater 68. Bauxite
propylene or pentene.
40 treater 68 functions in conventional manner of treater
¿i7 and removes essentially all of the chemically bound
It is also to be understood that the optimum usage of
fiuorine remaining in the hydrocarbon. The total alkyl
alkali metal iluoride promoter will vary somewhat with
ate product is passed from treater 68 by way of line
the particular olefin isomer; whereas the butene-l and
butene-Z isomers have Well delined optimums, isobutylene
71 into a fractionator 73. Fractionator 73 is provided
with a reboiler 74. It is to be understood that many
tends to a plateau maximum. Butene-l is benefited
most with respect to octane number improvement. Both 45 modifications of cutting up the alkylate product are
known. Herein the alkylate is simply cut into a C5-C7
|butene-l and butene-Z show a range of alkali metal
fraction shown as being removed by way of line 76, a
fluoride usage producing roughly constant octane number
C8 fraction shown as being removed by line 77 and a
alkylate product. And then the octane number drops
Cg-i- fraction being removed by Way of line 78.
with further increase in the amount of alkali present.
Liquid catalyst phase from line 41 is passed into a HF
Isobutylene shows very little adverse effect with large 50
column 101 provided with a heater 102. In this embodi
amounts of alkali metal fluoride present. The yield of
octane hydrocarbon and particularly trimethylpentanes
ment column 101 is operated to remove sufiicient HF
overhead by way of line 103 to obtain a concentrated HF
shows a relatively rapid decline lwith increased alkali
solution of alkali metal iiuoride. In this instance the
metal fluoride usage with both butene-l and butene-2;
butene-Z is much more responsive adversely with increas 55 concentrate removed from column 101 by way of valved
line 104 contains about forty parts by Weight of sodium
ing usage of alkali metal fluoride. Also on the produc
lluoride per 100 parts of HF. The HF tower overhead is
tion of hydrocarbons having fewer than 8 carbon atoms
passed by way of line 1193 into storage drum 106.
i.e. C7~- and hydrocarbons having more than 8 carbon
The concentrate from line 164 is passed into mixer
atoms i.e. C9+ the best results are obtained using alkali
60 108 where it is intermingled with a liquid hydrocarbon.
metal ñuoride in the ranges set out above.
The “HC solvent” is passed from source 111 by Way of
The invention is further illustrated with reference to
valved line 112 and line 113 into mixer 108. A stream
the following description of the drawing:
of the distillation residue from column 101 and solvent
The total reactor efiiuent is passed by way of line 2d
hydrocarbon from line 113 is withdrawn from mixer 108
into settler 26. Here the efñuent separates into a lower
liquid phase and an upper liquid hydrocarbon phase; the 65 and passed by way of valved line 116 into vessel 117.
The HC solvent boils above the boiling point of hydro
alkylate hydrocarbons are present in this upper phase.
gen ñuoride in order to permit complete removal of HF
The liquid hydrocarbon phase contains dissolved HF and
from the red oil and sodium íiuoride present in the stream
usually some occluded catalyst phase material. Liquid
from line 104. This solvent is also inert to the action of
catalyst phase is Withdrawn from settler 26 by -way of
line 28. Most of this liquid catalyst phase is recycled to 70 liquid HF. Heavy alkylate hydrocarbons are particularly
suitable material for this use. Sufficient HC solvent is
reactor 17 by way of line 29. A portion of the liquid
used to dissolve red oil present in the liquid catalyst phase
catalyst phase is sent to HF regeneration by way of
and to Wash essentially clean the surface of solid sodium
line 31.
formed by complete removal of HF overhead in
The upper liquid hydrocarbon phase is withdrawn 75 iiuoride
vessel 117. The amount of HC solvent used is dependent
said feed comprising isobutane and at least one olefin
containing 3-5 carbon atoms in a molar ratio of iso
butane to olefin of at least about 2, said catalyst consisting
somewhat on the temperature of -_operation `but mostly on
how completely free from red oil the solid sodium fluo
-ride is to be. In general ‘the amount of HC solvent will
fall in the range of Ñ257300 volumes per V10|() volumes of
HF passed to column 101.._
,
g
y,
,
essentially of liquid hydrogen fluoride and dissolved alkali
metal fluoride, in an amount on the order of 1_5 moles
,
of said alkali metal fluoride per 100 moles of hydrogen
fluoride present, (2) separating a liquid catalyst phase
from a liquid hydrocarbon phase containing alkylate hy
drocarbons, said hydrocarbon phase containing some
It is to be understood that the alkali metal fluoride
recovered _from the HF solution is atl ordinary tempera
tures mostly in the form of alkali metal hydrogen fluoride
„rather than the >simple alkali metal fluoride. However,
for -convenience herein this is always referred to as vsimply
catalyst phase material, (3) separating alkylate hydro
carbons from said hydrocarbon phase, (4) distillatively
removing essentially all of the hydrogen fluoride from
said catalyst phase, (5) contacting the distillation residue
alkali metal fluoride such as sodium fluoride.
Recovery vessel 117 is provided with an upper zone
118 and a lower zone 119.
Each of these zones being
including alkali metal fluoride from said step 4 with a
provided with an internal heater 121 and 122 respectively.
liquid hydrocarbon having a boiling point above that of
hydrogen fluoride to dissolve the hydrocarbons present in
said residue, (6) separating hydrocarbon solution obtained
In zone 118 most of the HF introduced through line 116
is vaporized overhead and passed by way of valved line
124 into storage drum 106. The slurry of solid sodium
fluoride in liquid hydrocarbon consisting of hydrocarbon
solvent and dissolved red oil flows through a perforated
in said step 5 from solid alkali metal fluoride and (7) re
from the washed solids or filtered away therefrom. Then
the solid sodium fluoride can be dissolved in liquid HF
and recycled to the reactor 17. In another example, the
hydrocarbon solvent can be introduced into the liquid
catalyst phase prior to the removal of any HF overhead.
Also procedures are available whereby the recovered sodi
separating alkylate hydrocarbons from said hydrocarbon
phase, (D) distillatively removing hydrogen fluoride from
cycling said alkali metal fluoride to said step l.
2. The process of claim 1 wherein said alkali metal
partition 12'6 into lower zone 119. In lower zone 119 the 20
fluoride is selected from the class consisting of sodium
remaining HF is distilled and passed into zone 118. This
fluoride and potassium fluoride.
zone 119 also is adapted to permit de-cantation of hydro
3. The process of claim 1 wherein said alkali metal
carbon solvent from a thickened slurry of solid sodium
fluoride is sodium fluoride and said amount is about 2-10
fluoride. Hydrocarbon solution consisting of solvent and
dissolved red oil is withdrawn by way of valved line 131 25 parts by weight of said sodium fluoride per 100` parts by
weight of hydrogen fluoride present.
and passed from the system by way of line 132.
4. The process of claim 3 wherein said amount is about
The thickened slurry is withdrawn from lower zone 113
2~6 parts by weight of said sodium fluoride per 100 parts
by way of valved line 134 and passed into mixer 136.
by weight of hydrogen fluoride present.
Liquid HF from storage drum 106 is passed by way of
5. The process of claim 1 wherein said temperature in
valved line 141 into mixer 136 where it dissolves the 30
step l is about 60-80° F.
sodium fluoride. The material from mixer 136 is passed
6. The process of claim l wherein said catalyst/feed
by way of line 142 into settler 143. In settler 143 the
-ratio is about l-3.
remaining hydrocarbon solution separates and is with
7. The process of claim 1 wherein said isobutane to
drawn by way of valved line 144. This solution can be
reused if desired by passing through valved line 146 and 35 olefin ratio is about 2-100.
8. A hydrogen fluoride catalyzed alkylation process
line 113 into mixer 108. Usually the hydrocarbon solu
which comprises (A) contacting, in the liquid state, a
tion from line 144 is discarded from the system by way
hydrocarbon feed and a catalyst, at a temperature on the
of valved line 148 and line 132.
order of 30°-130° F., for a `time to convert substantially
The liquid HF solution of sodium fluoride is withdrawn
from settler 1'43 and recycled by way of valved line 151 40 all of the olefins in said feed to alkylate hydrocarbons,
at a volume ratio of catalyst to feed of at least about 0.6,
and lines 43 and 29 to reactor 17. Some loss of sodium
said feed comprising isobutane and at least one olefin con
fluoride does occur and make up sodium fluoride is intro
taining 3-5 carbon atoms in a molar ratio of isobutane
duced into the system from source 153 by way of valved
-to olefin of at least about 2, said catalyst consisting es
line 154.
‘It is to be understood that other procedures for recover 45 sentially of liquid hydrogen fluoride, HF-soluble hydro
carbon and dissolved alkali metal fluoride, in an amount
ing red oil free sodium fluoride from the liquid catalyst
on the order of 1_5 moles of said alkali metal fluoride
phase can be readily devised. For example, all of the
per 100 moles of hydrogen fluoride present, (B) sep
HF can be removed from theliquid catalyst phase of
arating a liquid catalyst phase from a liquid hydrocarbon
line 31. The distillation residue of solid sodium fluoride
and red oil can be washed with hydrocarbon solvent to 50 phase containing alkylate hydrocarbons, said hydrocar
bon phase containing some catalyst phase material, (C)
remove the red oil and the hydrocarbon solution de-canted
said catalyst phase to obtain a concentrated HF solution
of alkali metal fluoride, (E) distillatively removing essen
tially all of the HF from the concentrate of step D, in
the presence of an alkylate hydrocarbon boiling above
HF to obtain a mixture of solid alkali metal fluoride and
urn fluoride can be introduced as a solid into the circulat
a solution of said HF soluble hydrocarbons in said alkyl
ing liquid catalyst phase of line 29; or even directly into
60
reactor 17.
It has been determined that the instant process that is
described above provides maximum yields of octane hy
drocarbon alkylate, based on olefin charged, and isomeric
ate hydrocarbon, (F) separating hydrocarbon solution
obtained in said step E from solid alkali metal fluoride,
(G) dissolving said solid alkali metal fluoride from step
F in liquid hydrogen fluoride, and (H) cycling said alkali
distribution affording octane numbers approaching 98
metal fluoride-HF solution to said step A.
ASTM research clear.
9. A hydrogen fluoride catalyzed alkylation process
which comprises (A) contacting, in the liquid state, a
The foregoing coupled with a 65
reasonably simple recovery operation of the liquid HF
catalyst system provides a process suitable for commer
cial use.
hydrocarbon feed and a catalyst, at a temperature on
the order of 60°-80° F., for a time l‘to convert substan
tially all the olefins in said feed to alkylate hydrocarbons,
Thus having described the invention what is claimed is:
1. A hydrogen fluoride catalyzed alkylation process 70 at a volume ratio of catalyst to feed of about 1-3, said
feed comprising isobutane and butene in a ratio of iso
which comprises (l) contacting, in the liquid state, a
butane to butene of at about 2-100, said catalyst con
sisting essentially of liquid hydrogen fluoride, HF-soluble
order of 30°-l3‘0° F., for a time to convert substantially
hydrocarbon and dissolved sodium fluoride, in an amount
all of the olefins in said feed to alkylate hydrocarbons, at
a volume ratio of catalyst to feed of at least about 0.6, 75 on the order of 2-6 parts by weight of said sodium fluo
hydrocarbon feed and a catalyst, at a temperature on the
â
ride per l0() parts by Weight of hydrogen ñuoride present,
(B) separating a liquid catalyst phase from a liquid hy
drocarbon phase containing alkylate hydrocarbons, said
hydro-carbon phase containing some catalyst phase ma
terial, (C) separating alkylate hydrocarbons from said 5
hydrocarbon phase, (D) distillatively removing hydrogen
and a solution of said HF soluble hydrocarbons in said
alkylate hydrocarbon, (F) separating a hydrocarbon so
lution obtained in said step E from solid sodium fluoride,
(G) dissolving said solid sodium ñuoride from step F
in liquid hydrogen fluoride, and (H) cycling said sodium
fluoride-HF solution to said step A.
fluoride from said catalyst phase to obtain a concentrated
HF solution of sodium fluoride, (E) distillatively remov
ing essentially all of the HF from the concentrate of step
D, in the presence of an alkylate hydrocarbon boiling
above HF to obtain a mixture of solid sodium fluoride 10
References Cited in the ñle of this patent
UNITED STATES PATENTS
2,416,000
2,459,775
Frey ________________ __ Feb. 18, 1947
Passino ______________ __ Ian. 18, 1949
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