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Патент USA US2404483

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July 23,` 1946.
_
’ , _-F, E FREY
.
2,404,483
PRODUCTION .OF MOTOR-FUEL HYDROCARBONS
`ATTORNEYS
Patented July 23, 1946v
2,404,483 `
gUNITED STATES PATENT musici:?
2,404,483
?RoDUcT'IoN oF MOTOR-FUEL
HYDRooARBoNs
Frederick E.» Frey, Bartlesville, Okla., assigner to
Phillips Petroleum Company, a corporation of
Delaware
Application March 12, 19424, Serial No. 4311.429>
9 Claims. (Cl. 260f-683A)
1
This invention relates to the conversion of hy»
drocarbons. More particularly, it relates to the
production of motor-fuel hydrocarbons from rel->
atively low-boiling hydrocarbons by a process in
which
application
hydrofluoric
is a continuation-in-part
acid is used as a catalyst.
of my co
2
n the product usually is of lower quality in respect
to octane number and is produced in lower yield
than that obtained by alkylating the correspond
ing isoparañins.
In such alkylation processes, the hydroñuo‘ric
acid eventually becomes so spent or deactivated
pending application, Serial No. 426,627, filed J an
by acid-'soluble and/or nuoro-organic by-pred'
uary 13, 1942, and Serial No. 432,679, filed Feb
ucts that it is unsuited for continued use; the
spending or deactivation is especially rapid at
elevated temperatures, such as those required for
ruary 27, 1942.
f
Y
An object of this invention is to convert rela
tively low-boiling normal parañin hydrocarbons,
the alkylation of normal parailins, Disposal of
such as normal butane and/or normal pentane,
the spent acid is a considerable problem, be--
to higher-boiling saturated hydrocarbons.
cause of the corrosive nature of the acid; fur
thermore,- heretofore no use for the spent acid
Another object of this invention is to produce
a motor fuel stock from relatively low-boiling 15 has been known, so that in the past it has been
necessary to provide `acid-recovery steps, such
paran-ins by a process in which used hydroiiuoric
as distillation to recover the free hydrogen flu
acid catalyst from an alkylation step is used as
oride, and thermall decomposition> and distillation
a catalyst for is'omerizing normal paraiiins to
to liberate and recover the organically c_ombined
isoparaflins suitable for use in the alkylation
20 fluorine as hydrogen fluoride.
step.
.
The product obtained by catalytic alkylation
A specific object is to combine, in a process
usually consists of primary alkylation products,
for converting normal butane to motor fueljan
for example when alkylating isobutane with
isomerizing step with an alkylating step in such
butylenes the product usually consists predomi
a Way that the material charged to the alkylating
nantly of octanes with relatively small propor
step is substantially free from normal parafûns.
Another specific object is to produce a motor
fuel of high octane number in increased yield and
of increased volatility as compared to that which
is produced by ordinary alkylation processes. ,
tions of low-boiling hydrocarbons such as pen
tanes and hexanes. Because of this fact, it is
usually' necessary to increase the volatility of the
prr'aduct,` so that it may be' ‘efficiently used as in
A specific object of this invention is to produce 30 aviation gasoline, by adding-„additional relatively
low-boiling hydrocarbons, stitch as lsopentane and
a motor> fuel stock from relatively low-boiling
branched hexane's.
'
parafflns by a combination isomerization-alkyla
tion process in which an azeotropic mixture of
hydroíiuoric acid and an isoparaliin is distilled
from the e?lluent from an isomerizing step and
is passed to an alkylating step.
Other objects and advantages of this inven
tion will be apparent from the accompanying
description and discussion.
Isoparaf?ns of relatively low molecular weight,
such as isobutane and isopentane, can be reacted
in the presence of an alkylation catalyst, such
as concentrated hydroiiuoric acid, at a compara
I have now found that spent or partly deacti
vated hydroiluoric acid from an alkyl'ating step
can be advantageously used as a catalyst inA an
isomerizing step to convert relatively low-boiling
normal 'paraflins such as normal butane and/or
normal pentane, into isop'aïraflins, such as isobu
tane and/or i's‘opentane, that are suitable for' con'à
version» to` motor-fuel hydrocarbons in the alkyl'
atin'g step. .I have also found that appreciableì
proportions . >of
motor-'fuel
hydrocarbons
are'
formed by secondary reactions 'in this isomeriz
ing step, and that these hydrocarbons can be‘
tively low reaction temperature, for example, in
' the range of 0 to 200° F., With alkylating reac 45 advantageously added to the product of the al-v
kylatingÁ step to increase the yield and the vola
tants such as oleiins having 3 to 5 carbon atoms
tility of aviation-'grade motor fuel’. Further, I
per molecule and corresponding alkyl compounds
have found that from the effluent from suchV a
such as alkyl halides, alcohols, ethers, esters, and
conversion can» be distilled. a low-boiling or' azeo
the like, preferably those of secondary or tertiary
tropic'mix'ture ‘comprisingv isobutane and hydro~
structure, to produce hydrocarbons in the motor
fuel range which have high antiknock values and
-that are suitable for use in aviation gasoline.
Normal paraflins, such as normal butane and nor
mal pentane, can, alsol be alkylated„but only un
der considerably more drasticv conditions, so that
gen fluoride, which 'is' suitable for use as feed
material to' an alkylating. stepl
~
In one speciñc embodiment, for example, the
present invention comprises isomerizin'g normal
butane by' the ison'ieriz'ingv action of hydroflùorí'c
2,404,483
3
acid previously used in an alkylation step, using
the resulting isobutane for conversion to motor
vantageous in order to favor the desired olefin
isopara?in junctures, or alkylation reactions, and
‘V fuel hydrocarbons by hydroñuoric acid-catalyzed
to hinder undesirable olefin-olefin junctures, or
polymerization reactions. Preferred operating
alkylation, and combining the products boiling
above the butane range in such manner as to
conditions in alkylator I5 are a temperature in
the range of 30 to 150° F., a pressure sufficient to
l obtain a motor fuel of desirably high anti-knock
rating and volatility»-` . ~
maintain allcomponents in the liquid phase,~ and
L
An advantageous feature of my invention is ’an `
a' reaction'time of about' l'to 30 or 'more min
azeotropic-distillation step, interpositionedy be
utes; but if desired other conditions may be used
tween an isomerizing step and an alkylating step, î 510 ¿in_îiparticular cases without passing beyond the
for separating isobutane and lighter _hydrocar
„bons from v’normal vbutane and heavier"hydro-gL ' '
carbons.
_ scope of> this invention.
',TheJjres'ulting mixture passes through conduit
By this particular step, an eflìcient'" ' 25'having valve 26 to separator 2l, wherein it is
: - effected
separation
with
of aisobutane
minimum from
of .-lfractionating'
Ínormal, butanejs"-equip
i5
_separated'into two liquid phases as by cooling and
gravitational or’ centrifugal means.
ment. The resulting overhead mixture com
The heavier or hydroiluoric acid phase is passed
prises, as well as isobutane, a substantial pro
through valve 28, and conduit 29 to pump 30. If
portion of hydroñuoric acid in a relatively'aètive ` ' ’i " desired, however, part of the acid may be recycled
to alkylator- I5 through valve 3I and conduit 32.
‘ for
and use
anhydrous
as catalyst
condition2
in an inalkylating
which it step;
i'sÍs'u'itabl'é
this 'Íí
The lighter or hydrocarbon phase from sepa
20
l overhead mixture is'advantageously _charged di
rator 21 is passed through valver33 and conduit
34 _to -Y-debutanizer 35. An overhead fraction,
which is¿usual1y .predominantly isobutane but
‘ rectly to the alkylating stepwith no prior treat
‘ ment other than condensing andcoolingto a>
`
suitable temperature.
`
-
-
Another advantageous feature o_f-.my invention
which at times may comprise other gases and
25 vapors,> lsuch as .hydrofluoric acid, propane, and
` liquid hydrocarbons, chiefly isopentane'and iso-f'
normal butane, may be passed from debutanizer
35 through valve 36 and conduit 3l to fractionator
merio hexanes, which areproduced by sideI and
l0; if little or no normal butane is present, this
l is the blending oflow-molecular-weight.normally 1
fraction preferably is passed directly to alkylator
ï the'` alkylate produced in an alkylation step to 30 I5, as through valve 38 and conduit 39. Prefer
; increase = the volatility of the alkylate.` lThese
ably also, when there is'some excess propane
low-molecular-weight normally liquid hydrocar-~l
and incidental _diñicultly condensible gases, such
Y ‘ secondary reactions inA an isomerizing step„with
‘ bons are preferable Vto natural-gasoline fractions
of a corresponding boilingrange, which are some
as methane and ethane, part of the debutanizer
overhead is passed through valve 40 and conduit
times blended in motor fuel to increase its vola
35 4I to depropanizer 142, from which these gases are
tility, because , they -comprise relatively larger
passedthrough valve 46 to separator 16, and from
proportions of branched-chain parañ'ins andV
which the resulting 1 concentrated butanes are
Y1 hencehave higher octane numbers than vthose
I of the" natural-gasoline fractions.V . 1;
`
.
passed to fractionator I0 throughvalve 41. A
normally liquid kettle product fromdebutanizer
.
All understandîngbflsûme; aspects of my in-v 40. 35 is passed through valve 43 and conduit 44 to
vention maybe aided by a considerationof ,the
rerun column 45 wherein it is separated’into two
fractions: (l) a major motor-fuel fraction com
prising hydrocarbons suitable for Yuse in aviation
practicingthe invention and Figure 2 aschematic
gasoline, which is withdrawn through outlet 48
flow-diagram. 0f . another arrangement for
4,5.. having valve 49, and (2) a bottom fraction com
‘ accompanyingdrawings, in which Figure 1 isa
l schematic~flow-diagram of one arrangement for-
`ticing my invention.
.
t
.
,
_
prising hydrocarbons boiling above Vthe motor-fuel
range, which is withdrawn through outlet> 5.0 hav
,.
Referring now to Figure 1, a low-boilinghydro-~
i
.
h
‘
ing valve 5|.'
v
v
carbon material, for example‘a mixture of normal
butane and isobutane, is admitted to fractionator
Normal butane from f_rac'tionator I0 and hy
I0, as through inlet II- having valve I2 and/or 5,0. drofluoric acid from separator'21‘are forced by
through conduit 3'I.> 1 By fractionator I0 it is sep-l
pumps I8 and 30, respectively, through heating
coil 52 to reactor 53, wherein the normal butane
is isomerized to isobutane to afsubstantial extent.
‘ arated into a concentrated isobutane fraction,
which is passed through valve I3 and conduit I4
, to alkylator I5, and .into anormal butane.r frac
If desired, additional normal butane may be ad-‘
tion, which is passed through valve I6 and con- . 55 mitted, as through inlet 54 and valve 55; at times
`duitI'I to pump
I8;
Y
~,
1
such normal butane may be the sole paraffin feed
.
In alkylator I5, the isobutane is mixed .under
alkylating conditions with an alkylating reactant,
§ such as an olefin of three to five carbon atoms,
to the process.
,
v
I
`
"
In the feed to reactor 53, the ratio of hydro
fluoric acid to hydrocarbon is preferably in the
‘ per molecule, preferably butylene,rwhich.may .bel 60.
range of ~-`about 07.2;1 to 4:1 or Amore by weight;
admitted through inlet I9 -andvvalve 20, and with-
usually, operating with an acid-to-hydr'ocarbon
concentrated hydrofluoric acid, preferably anhy
ratio within this range will effect the maximum
` drous, which maybe admitted through inlet- 2I;
and valve 22 and/or through conduit 23 asthe'
l alkylation catalyst.
.
'
.In the composite feed to alkylator'l 5, the `weight
‘ ratio of ~isoparai‘flns to olefins, or Aotherxalkylatin'g
conversion of normal paraffins to isoparañlns.
The exact ratio desired for any particular case
may be obtained by controlling the relative pro
V portions of spent acid from separator 21 that pass
through valves 28 and 3|, respectively.
reactant, preferably is in the range of 2:1 to 20:11.
_ The temperature in ,reactor 53 may be within
i or more, andthe-weight ratioof hydrofluoric acid
the „range of about 250 to 1000° F. A temperature
l to total hydrocarbons preferably is in the range.
012:1 toz4z1. The olefin preferably isxìntroduced
inthe range 400 to 800° F. is usually preferred; ,
. :into the reaction mixture under conditions of
at low temperatures the rate of reaction is low,
and at high temperatures some cracking and car
\ high .turbulence , and/or in multipointwise. fash
bon ¿formation , occurs.V
` ion, so that it' is rapidly mixed and diluted vwith
withinv the range of atmosphericto 5000 pounds
the isoparafûn reactant. .z ¿Thisprocedure isead
The pressure may be f
75 per square inch or. more; Vusually it is preferred, f
2,404,483
.The resultingv mixtureïin'reactor IIS is passed
for reasons of economy in equipment and operating costs, to use> a pressure inthe range of 250
to'2000 pounds per square inch. The reaction
through valve ||9 and conduitl |2D.»to partial
time may be within the range of about 1 to about'
hydrocarbons Vboiling :above approximately the
pentane range, heavy hydrofluoric acid-soluble
condenser I2I, wherein, by a suitable cooling
means, relatively high-boiling material, such as
300 minutes depending chiefly upon the temper
ature; the time required decreases with increase
in temperature.
material, and the like, are condensed or lique
If the reaction time is very
ñed. Suitable conditions in partial condenser .
I2 I i are a temperature in the range of 125 to 400°
short, such as 1 to 5 minutes, the reaction can be ».
completed in coil 52 or an .extension thereof;
F. and a corresponding pressure in the range of
whereupon reactor 53 may be by-passed orre 10i 15 to 400 pounds per square inch. The optimum
moved from the system by means not shown.
conditions. are readily determinable by trial
Preferably, the reaction zoneispacked with a
contact mass, such'as steel turningsyalumina,
bauxite, or other material resistant to corrosion
by hydrofluoric acid and> suitable for promoting
the reaction and/or heat` transfer.
_. .
and/or from well-'known vapor-pressure rela- v
tionships. of the various constituents. Condi
15 tions'outside the. ranges given above may be.
used, if-desired or necessary for any particular
.
case.
' The resulting mixture from reactor 53 is passed
1
.
,
~
~
The Vresultingpartly liquefied mixture from
through valve 56' and conduit 51 to separator 58,
wherein it is separated into two liquid phases as
partial condenser |2| is passed through conduit
|221. and valve |23‘to separator |24, wherein it is
by cooling and gravitational or centrifugal means. 205 separated into a‘ gas phase and a liquid phase.
, Although the heavier or hydrofluoric acid phase.
from separator 58 may be recycled to >coil 52 and/
or alkylatcr I 5„as through valve 59 and/or valve
60, at least a part of it is preferably passed
through valve 6| and conduit 62 to `iractionator
63. In'this- fraction tor it is separated into (l)
an overhead fraction comprising substantially
The temperature and the pressure. should bev as ,
nearly as possible the same as those in partial
condenser |2I. The »liquidphase which com
25
prises mainly . hydrocarbons and acid-soluble
substances boiling approximately in the hexane
range and above, is Withdrawn through valved
outlet |25. The gas phase is passed through
anhydrous ` hydrofluoric. acid, which is passed
valve |23 andconduit |21 to condenser |28.
through valve 64 and conduit >23 to alkylator I5,
In condenser |28, the gas phase from separator
and (2) a bottom fraction, or sludge, comprising 30 |24 is‘cooled and liquefied. The resulting liquid „
acid-soluble materials, which maybe withdrawn
mixtureV of acid and hydrocarbon phases, which
comprises hydrofluoric acid, isoparaiiins, and un
reacted normal paraii‘ins, is passed through Valve
through valved outlet 65. .
The lighter or hydrocarbonphase from sepa-_
rator 58 may bel passed through valve-63 and
|29"v and conduit. |30 Vto fractionating means ISI.
conduit 31 to fractionator Il); however, in order 35 'Two fractions are withdrawn from fractionat
to Yrecover valuable normally liquid hydrocarbons
in'g means |3I'. The 4overhead fraction, which
produced in the isomerizing step .by secondary re
comprisesl a »low-boiling azeotropic mixture >of
actions, it is preferably passed through valve 61`
hydrofluoric acid Iand isobutane, and. usually
and conduit E8 .to debutanizer ÍB9, »wherein it is 40 some lower-boiling material such as propane, is
separated into fractions, The overhead fraction,
passed through valve |32 and conduit |33 to
which comprises propane, normal butane, and
alkylator |34. The bottom product, which com
isobutane, and generally some hydroiiuoric acid, `
prises hydrofluoric acid and hydrocarbons boil
is passed through valve 10 and conduit 1| to‘de
ing above isobutane, rmay be recycled in part
propanizer A4,2; the bottom fraction, which com
prises isopentane, hexanes, and other hydrocar
bons, maybe withdrawn through outlet 12 hav
ing valve 13, but is preferably passed, at least in
part, through valve 14 and conduit V15, together
with normally >liquid alkylation products from
45
through Avalve |35 and conduit |36 to coil II1;
preferably, however, most of it is passed through
valve |31 and conduit |38'to separator |39.
‘
In separator |39 the kettle fraction from frac
`tionator |3I is separated into two liquid phases.
The
debutanizer 35, to rerun column` 45. ,
-lighter or hydrocarbon phase is passed through
-In separator ,16. hydrofluoric acid is separated
valve |40 and conduit I4Ito debutanizer |42.
as a liquid phase from the overhead fraction from , The heavier'or hydrofluoric acid phase may be
depropanizer 42, as by cooling and ¿gravitational
passed in part through valve |43 and conduit |44
means. The acid _may- be withdrawn .through
for use as catalyst in alkylator |34, but pref-k
valved outlet 11, but/preferably is recycledto
erably most or all'of it is recycled through valve
alkylator I5` or coil 52 by _
4
>|45 and conduit |46 to pump |I6.
pane and vother light gasesare withdrawn through
valved outlet 18.
A part or all of the` propane
504 as by cooling andy gravitational means.
In alkylatorV |34 the overhead mixture »com
prising hydroñuoric acid ‘ and `isobutanle from
containing fraction removed from the top of de- `
fractionator |3I is mixedv under alkylating con
propanizer 42 may be passed directly to the isom 60 ditions with an .alkylating‘ reactant, >such as >an
erization step :through conduit 8D, controlled by
olefin having from: 3 to 5l carbon atoms per’ mole
valve 8|, to conduit I1 and heater y52. ¿_
cule, or'an‘equivalent alkyl compound, which is
Referring now to> Figure> >2 a suitable hydro-iv
introduced‘thr'ough inlet |41 and valve |48. Since
carbon material, such as amixture comprising 65 the overhead mixture usually contains insuffi
chiefly normal paraiiins, preferably normal
cient hydrofluoric acid'for effecting with desir
butane, is admitted through inlet ||I, valve I I2,
ably high emciency. the alkylation ofthe iso
and pump `||3. To this hydrocarbonfmaterial
butane, additional alkylation catalyst is admitted
is added >hydrofluoric acid previously usedin the
through inlet |49l and valve |50 Áand/or through
alkylation step, from acid-recycle conduit |46,
conduit |44. Such additional alkylation catalyst
by pump Il_6; if desired, additional acid may be
may be any of the alkylation catalysts that» are
admitted throughinlet ,l I4 and ‘valvev |~-|5. The
operative in the presence of hydrofluoric acid,
resultant acid-hydrocarbon; mixture is ypassed
Vbut for the sake of simplicity and' of eliminat
through heater i|1 to reactor. I I8.4 The -oper-A
ing otherwise necessary subsequent catalyst
ation of heater I I1¿¿and reactor,` IIS. ,are-.,substan»,
segregating'steps, it may be taken to be addif.
tially as described for `_heater 52 and reactor 53. . 75
2,404,483
7
tional i hydrofluoricv acid, which, is. preferred.
Usually the hydroñuoric `acid admitted‘rthrough`
inlet |49 may be the sole vcatalyst; feed to thel
system.
In the feeds
.
.
to?alkylator
. .
fluoric .`acid,' is recycledïthrough valve |13 and
conduit I14tothe`isomerizingrstep." The bottomfraction;v which. comprises.r low-boiling normally
liquid hydrocarbons, such'as isopentane, hexanes,
|34
,
the weight
.
. ratio
.,
and heptanes, may‘be. Withdrawn through outlet
of isobutane toV olefin, or other alkylating re-'
actant, is preferably in the range of 2:1 to 20:1
|15 having valve . | 16; preferably, however, atleast
ai part v‘of it is passed through valve |11 and con
i or more, and the weight ratio of hydroñuoric
duit |18 Vto fractionating means |60, wherein it
acid to totalhydrocarbons‘is preferably in `the
becomes 'blended'with the liquid alkylation prod-.
‘ >range 0.2:1 to 4:1.. The oleñn is preferably in
l troduced into the reaction mixture Vunder con
‘
ditions
A fejw'of the- many -aspects'of my invention are
of 1 high turbulence Vand/,or ' in .multi- ‘
illustrated bythe following' examples, `which are
illustrative, but not necessarilylimitative;of the
pointwise fashion,„so that it is Vrapidly mixed
` with- the »isobutane. This .procedure .is advan
l tageous in order to favor the desired .oleñn-iso
1 vparaffin junctures, or alkylation reactions, and to
l hinder
undesirable
olefin-olefin
junctures,
invention.
15
-'
"
.
Y
"
.
"
§"Eœamplel'
'
.
'
, In an arrangement similarto that illustrated in
- Figure. _1, `a mixture ofl approximately equal pro
or '
polymerization reactions. Preferred operating
portions of "normal butane and »isobutane' is
l conditions in alkylator |34 are a temperature in,
the range of 30 to 150° F., a pressure suflìcient
to maintain all components in the liquid phase,
charged to a fractional-distillation column, from.
Whiclr an overhead fraction consisting chieñy of
q and a time ofaboutV 1 Vto 30 orV more minutes;
i'sobutane> is passed to an alkylation step, and from
l however, conditions outside of these ranges may
which y a bottom fraction consistingr chieiiy of
normal butane is passed to an isomerization'step.
` beyond the scope of this invention.
25 Butylenes and concentrated hydrofluoric acid are
separately ‘charged to the alkylation step. In
The resulting mixture passes through conduit
this alkylation step, conditions are approximately
i |5| and valve |52 to separator |53,\wherein_it is
separated into two liquid phases as by cooling
as follows: temperature, 85° F.; pressure, 125
and gravitational or centrifugal means.
pounds per square inch; reaction time, 6 minutes;
Part of the heavier or hydrofiuoric acid phase
isobutane-to-oleñn molal ratio (in thegmaterials
entering the" alkylation reactor), 10:1; hydro
maybe recycled through valve. |54, conduit |55,
"ïand .pump |56 to alkylator v|34;’preferably an
carbon-to acid weight ratio, 1,5:1; .and rapid
amount. of acid approximately equivalent to„or
mixing to maintain intimate contact between the
alsobe used in particular cases without passing
Y lsomewhat greater than, that introduced to the
acid and hydrocarbon phases.
lallfzylator in the overhead fraction from frac
ltionator |3| is passed through valve V|51 and
alkylation
catalyst.
.
. .
The lighterv or hydrocarbon phase
_
.
from
separator |53is passedthrough valve |58 and
conduit |59 to fractionating means |60, in which.
.
'
.
is separated by gravity intoA two liquid layers. The
`conduit |46 to pump ||6 for use in thejsomeriz
ing step. VIt is a particular feature of this in#
' vention that the catalyst used for effectingth'eKY
isomerization reaction is Ya hydroiluoric .acid 40
, which is discharged from the alkylation step asA
spent
^
Y The resulting eiiiuent fromV the alkylation step
heavier `_or acid layer is passed to'the isomeriza‘
tion? step. The lighter orv hydrocarbon layeris`
debutanized ; the Voverhead fraction, comprising
chiefly unreacted iscbutane'and hydroi'luoric acid,V
is recycled to the alkylation step; the bottom frac
tion,v comprising normally liquid hydrocarbons,` `
is passed Vto >a rerun column.
In theisomerization step,
proximately
as follows:
»_
ì
conditions are ap-k
temperature,
500° F.;
pressure, „750 pounds per square inch; time, Y4.5
it is separated into the following four fractions:
(1) a low-boiling fraction comprising propane
minutes;j hydrocarbonp-to-acid ratio, about 1:1 f
and hydrogen fiuoride with minor proportions of t by- weight; and a contact mass comprising steelk
turnings _in the reactor.
incidental gases, such as methane and ethane,
which may be passed through conduit | 6| and 50i. The eiiiuent from the isomerization step' isl
cooled and separated into two liquid phases. The
valve |62 to separator |63; (2) a major fraction
comprising isobutane, which is recycled via valve
heavier or acid phase'is‘fractionallyV distilled' to
\ recover hydroiiuoric acid, which is returned to
|64 andr conduit |33 to alkylator |34; (3) a frac
the alkylation step. The lighter or hydrocarbon
tion of highly branched paraiñnic reaction prod-V
phase is also fractionally distilled; it has a hydro- "
ucts boiling within the „motor-fuel range, whichA
-` carbon ‘composition about as' follows, in‘per cent
iswithdrawn through outlet1|65 having `valve
|66; Vand (4) a relatively high-boiling hydro ' "by «weighty propane, 10; isobutane, 26; normal
butarie, 51.; pentanes (mostly isopentane), 10;`
carbon residue, which is Withdrawn through out
hexanes, 3. AnVV azeotropic mixturejof propaneA
let |61 having valve |58. ...Preferably to increase
the over-all yield, part of the propane-rich low-V 603 and hydrofluoric acid is recycled to the yisomer
ization* step; the excess propane'is withdrawn
boiling fractionis recycled through valve | 69'and
>from the process; the isobutane is passed to the>
conduit |10 to coil |.|1 of the isomerizing step’.V
`In separator |63, by cooling and gravitational
alkylation step;l the normal butane isrecycled to
the isomerization step; and the normally liquid
means, a liquid hydroñuoric'acid phase is sepa-V
rated Yout. This hydroñuoric acid phase may be
material heavier than butane is passed to the
withdrawn through valved outlet |1|, or it’V may
rerun column.
be recycled to 'alkylator |34 or to coil ||1 by
means not shown in the drawings.
In thevrerun column, themixture of normally
lthe isomerization steps` is fractionally distilled
carbon residue (gas and/or liquid) is withdrawn
through valved outletY |12 and .disposed of in any
suitable manner.
`
'
'
_
'
In debutanizer V|42 the hydrocarbon phase'from
separator |39 is separated by distillation into .two?`
fractions. f Thejoverhead fraction, which' com-_
prises mostly fno'rmal’butane 'with' some lhydro-.--
liquid hydrocarbons fromboth the alkylation and
toyield an overhead fraction of aviation-range
l. motor-fuel hydrocarbons anda vbottom fraction
of higher-boiling hydrocarbons.
The yield of
motor-fuel hydrocarbons is about 205 per cent byV
weight of the butylenes charged to the alkylation
step. The motor-fuel product-has an octane num;
Aber of about 91 and a desirably high volatility'. - v
'
2,404,483
~ .H495
_,
,
1
_
Example II
-10
.
’
l
À
scheme that Will be-obvious `to those skilled-in the
art may be advantageous to facilitate the use of
\- In an arrangement- `similar tothat illustrated
in Figure 2, , normal `butane and concentrated
such
hydrofluoric acid are» charged to an isomerization
Stage.
,
hydrofluoric »a`cid.~. Some change in¿ the' flow
modiñers.
.
»
Y
'
.
`
’
Additional pumps, valves, conduits, coolers,
fractionators,- and other equipment, such as are
well-known in the art of hydrocarbon conversion,
may be used Wherever they are necessary orcon
vement for obtaining the results indicated in any _
The isomerizing conditions are approxi- -
»mately as follows: temperature, 425° ’Eg-pressure,
2000 pounds per square inch `(mixed-phase or
liquid-and-gas conditions); reaction time, 60
minutes; acid-to-hydrocarbon ratio, 1.521. The 10 particular case. The scope of my” invention should v
resulting isomerization eiiiuent comprises a hydro
not b'e unduly limited by specific numerical values
carbon mixture of approximately `the following
recited herein.
-l
"
" y'
vcomposition, in per cent by weight.: propane, v10;
Iclaim: "
Í
>
~î
,Y
'-f
isobutane,'26;» normal butano,l 5‘1; hydrocarbons
' "11. A process' yforiproducing'n‘iotorJ-fuel hydro
boiling higher than normal butane; ‘13.
'
f .
l
15
. From the isomerization efliuent is Withdrawn,
by partial cooling and gravitational settling, a
liquid product which comprises substantial pro
portions of'fpentanes and hexanes.l The" remain
trated hydrofluoric acid in anf -i'somerizat'ion
step; separating the >eiliuent _from said is'omeri'z'af .
ing material is passed to a fractionator from the
vtionisft'ep by distillation intoI an overhead fraction
bottomcf which amixture of hydrofluoric acid
and hydrocarbons (mostly normal butane). boil
ing above isobutane is recycled to the isomerizing
stage, and from theïtop" of ‘which a low-boiling
mixture comprising Vchiefly propane, isobutane,
'and' hydrofluoric acid is passedl to an alkylator.
The composition of this low-boiling mixtureîis
usually about 2'0 to 30 per cent b-y-'weight hydrogen
carbone,“Which"cömprisesr yisoiií'e'riZirig a; low
boilingl normal paraiìin Yof `--four Eto yiii/‘e carbon
atoms per >`molecule in 'the'. "presence of >concen
compri'singihydrofluoríc acid and an isoparafiin
of four to five carbon'at'orns per »mt'plec‘ule,V` and
into afbo'tto‘in- >fraction comprising hydroiiuoric
acid and ‘a normal paraflin having 'fourtoi’ive
Y25 carbon >atoms per molecule ;_ _passing Ésa'id bottom
ñuoride and 70 to 80 per 'cent hydrocarbons.>
Sufiicient additional or recycle'hydro?luoric acid
is introduced to the alkylatorfto bring'the acid
to hydrocarbon Weight Vratio up to about 1.1. A
relatively small'proportion of mixed butylenes,
preferablybelovsT about 20 per cent vby Weight of
Y fraction to said isomerization step; 'passing said
overhead fractíonvto an allrylating'step and alkyl-v
a'ting'said isoparafiin `with an added alkylating
reactant vinthe presence of-fsaid accompanying
hydrofluoric acid toV produce motor-fuel hydro
carbons; and withdrawing-the resulting motor
fuel hydrocarbons.
,
’
_
‘
2J The] process of claim 1, in vwhich said eñlu
ent is freed from material boilingA approximately
the'iso'butane, is introduced as alliylating reactant 35 above the pentane range by Ipartial condensation
into the alkylator.
prior .to said distillation.
rThe conditions in the alkylatorï are as follows:
temperature, 95 to 125° EL; pressure, 150 to 200
'
,
3. The process of claim 1, in which said normal
parafñn is normal butane.
.
Y i i
pounds per square inch; average reaction time,
4. A process forproducing va normally liquidy
«i minutes; and rapid agitation to maintain inti 40 isoparaflinic hydrocarbon lmaterialboiling in the Y
mate contact between acid and hydrocarbon
motor fuel range from lower-boiling normal par
phases.
f
afñn hydrocarbons of at least four carbon atoms
The resulting efiluent mixture from the alky
per molecule, which comprises subjecting such
lator is passed to a settler in which it is separated
a normal paraflin to catalytic isomerization in
into an acid phase and a hydrocarbon phase. 45 the presence of hydrofluoric acid as the isomer
Of the acid phase, a proportion equivalent to that
ization catalyst to produce low-boiling isopar
passing from the isomerizing stage to the alkylator
is recycled to the isomerizing step; the remainder
is recycled to the alkylator. The hydrocarbon
aflin hydrocarbons, separating from effluents of
said isomerization used hydrofluoric acid catalyst
and an isobutane fraction and a volatile normally
phase is passed to a fractionating means, from 50 liquid hydrocarbon fraction boiling in the motor
which are obtained various products and recycle
fuel range, reacting said isobutane fraction with
fractions, such as those indicated on the drawings
butenes under alkylation conditions and in the
as being obtained from fractionation means 160.
presence of said yused hydrofluoric acid catalyst
The motor-fuel fraction has a clear octane num
to produce irsoparafñns of higher molecular Weight
ber of about 90 and is suitable for use in aviation 55 and in the motor fuel range, separating an iso
gasoline.
'
f
paraflinic hydrocarbon fraction comprising `pyre
dominantly isooctanes so produced, andblending
tion, which will be obvious to those skilled in the
said isooctane fraction and said volatile liquid
art of hydrocarbon conversion. For example, if
hydrocarbon fraction separated from the isomer
the paraiiinic feed materialr comprises normal 60 ization step to produce a composite motor fuel
paraflins but substantially no isoparañins, it is
product.
advantageously admitted in the modification of
5. A process for producing normally liquid iso
Figure 1 to the isomerizingstep through inlet 5f?.
paraflinic hydrocarbons from a loWer-boilingnor
and Valve 55 instead of to fractionator It through
mal parañin hydrocarbon of at least four carbon
inlet Il and valve l2. Also, if desired, in order to 65 atoms per molecule which comprises subjecting
inhibit the formation of low-boiling hydrocarbons
such a normal paraiiîn in an isomerization step
in the isomerizing step, a propane-rich fraction,
to catalytic isomerization in the presence of '
such as that from the top of depropanizer dì’. mai7 .
hydroiluoric acid as the isomerization catalyst to
produce low-boiling isoparaffin hydrocarbons,
be recycled to coil 52 through conduit 80 and
valve 8l. Various catalyst modifiers that do 70 subjecting effluents of said isomerization to frac
not enter the alkylation reaction under the pre
tional distillation to produce a 10W-boiling frac
There are numerous modifications of my inven
vailing conditions, such as organic or inorganic '
compounds of thetype of primary halides or al
cohols, polyhalides, sulfur dioxide, organic nitro
gen compounds, and the like, may be added to thfy3
tion containing isobutane and hydrofluoric acid
’ and a higher-boiling fraction containing low
boiling normal paraflins and hydrofluoric acid,
returning said higher-boiling fraction to said iso
2,404,483
v
12v
V11
merization step, passing said low-boiling fraction
' , so formed, and blending the last said hydrocar
toY analkylation’step‘and reacting isobutane con#>
bon fraction with the aforesaid low-boiling hy'
drocarbon fraction to produce a'composite motor
tained therein with an alkylating'reactant in the
presenceof hydro?luoric acid as -the'lalkylation
catalyst to'produce isoparafiins of higher molec
ulanweight, and recovering a hydrocarbonfrac
tion containing higher l boilingïisoparaflins Vso
produced.
'
'
'
'
"
--
'
fuel stock as a product of the process.
8. A process for producing motor fuel, which
comprises in combinationjalkylating isobutane
with an oleñn of three to five carbon atoms vper
molecule in the presence of concentrated hydro
"
iìuoric acidl in an `alkylation step; separating
portion of the spent hydroi’luoric acid alkylation 10 from the resulting effluent from said alkylation
catalystV is passed to the isomerization stepas the
step a hydroñuoric acid fraction, anunreacted
isobutane fraction, and a normally liquid hydro
isomerization catalyst.
l
i
,.
~- 6. VThe process of claim 5 in which atleast a
` '
carbon fraction; >mixing »said hydroñuoric ¿acid
'7. Aprocess for producing an isoparaiiinic mo
Ytor Yfuel stockfcontaining both low-boiling and>
fraction with normal butane; subjectingîthe’ re-.
high-boiling isoparañînic hydrocarbons from low-` 15 sulting acidebutane rmixture to V"such" conditions
boiling normal paraii‘lns, which comprises sub
yjectingsuch anormal paraiiinto catalytic con
version in the presence of hydroiiuoric acid as‘the
in an isomerization step thatY said normal butane
is isomerized to isobutane to'aësubstantial ex
tent by hydrofluoric acid; separating l‘from the
resulting eilluent from `said isomerization >step
boiling.- normally liquid isoparafûns, separating> 20 used hydrofluoric acidcatalyst and an isobutane
fraction, an unreacted vnormal butane Nfraction,
from ellluents of said conversion a mixture Y'coniî
conversion catalyst to produce isobutane and' 10W-v
tainingvsubstantial quantities of yisobutane andv
substantiallyanhydrous hydrofluoric acid, sep'
V and a normally liquid lay-product fraction; re-V
cycling said unreacted'normal Vbutanefraotion
to said isomerization step; passing‘saidused hy- ,
aratinglalso a vlow-boiling liquid isoparañìnic - hy-`
` drocarbon fraction. »adding to said isobutanef. 25 drofluoric acid catalyst, said unreacted ilsobutane
hydroñuoric acid-mixture lan alkylating reactant
land' subjecting -the comb-ined mixture to alkylaîv
»tion conditions Ato produce high-boiling normally
liquid hydrocarbon fraction e and ’ lsaid Ynormally
liquid isoparaiiîns boiling in the-motor fuel range,
separatingvfrom eflluents of said alkylation spent
30 resulting normally liquid mixture a motor-fuel
hydrofluoric acid catalyst and passing-at least
fraction and Vsaid isobutane fraction 'toi said
alkylation step; mixing together "said normally
liquid llay-product fraction; separating from the
fraction;v and withdrawing from the process said
a substantial portion of same toV said -conver- l
sion, separating-also from veilluents »of said alkyl
-ation a normally liquid isoparañînicvhydrocarbon
fraction- containing said high-boiling isoparamns
Imotor-fuel
fraction.
~
'
„
'
,9. The process of claim 8 in which
is at least one butylene. .»
35
'
»said oiefin
'
FREDERICK E.
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