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Juäy 9, 1946.
F. E. FREY>
2,4%,650
RECONSTRUCTION OF' PARAIV‘FINS
Filed Fe‘b. 6, 1942
2 Sheets-Sheet l
July `9, 1946. _
F. E. FREY
2,403,650
l yRECONS'IJRUCTION 0F PARAFFINS
Filed Feb. 6, 1942
2 Shee‘ts-Sheet 2
Patented July 9, 19:46
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„i
2,403,650
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¥ UNI'TED` STATES PATENT ¥OFFICE
RECONSTRUCTION 0F PARAFFINS;
Frederick E. Frey, Bartlesville, Okla., assignor'v'to"
Phillips Petroleum Company, a _corporation of
’ Delaware
Application-February ,6, 1942, Serial No. 429,810
13 claims. (c1. 26o-¿6835>
1
v 2
_
nate .under relatively mild treating conditions.
The yield of cyclics, exempliñed _in the third equa
`tion bycyclohexane, is increased by increasing
drocarbons. More particularly, it relates to
chemical reconstruction of paraiiîns into, morev
highly branched parañins inthe presence of hy
droñuoric acid as av catalyst.
~ the Jtemperature and/or the time of reaction.
This application
ArfourthV type of reaction is believed tor account`
for the increase in saturation and stability that
occurswhen motor >fuel comprising some unsat-,
f urated material is treated. By this reaction, ole
is a continuation'in part ofy my copending appli
cation, Serial No. 426,627, ñled January 13, 1942.
An object .of this invention .is ., `to produce
branched parafñns fro-m relativelyY ¿ less highly
branched paramns.
-
Y
ailins, and isomerization, respectively, predomi
This invention relates to the conversionof hy
10 fins are converted lto cycloparaflins such as cy
`
cloheXane and its derivatives. This reaction may
_A specific object is to control, in `a, process forv
converting parañîns in the presence of Vhydro
beeXempliñed as follows: o
fluoric acid, the proportions and :the molecular;
Weight or volatility of the‘hydrocarbons producedY
that differ in molecular weight fromV the'v feed.
material.
HF
Another specific object is to produce 10W-boil# i
ing isoparafûns from normal butane.
Another specific object is to produce loW--boil-`
ing îsoparañîns from normal pentane.
_
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Y
I
f
Several other types of reactions undoubtedlyoc
cur in the 'reconstruction process; however, the
above-mentioned ñve types appear to account forv
`most‘of the eñïects which arer produced. The
general term “reconstruction” is used herein toV
denote the production of one or more of the
above-mentioned effects and/or of other inher
20
Another specific object is to minimize the dep- /
osition of non-volatile material in the reaction
zone of a process for converting parañinsin the
ent advantageous effects which result from the
~
'Y practice of my invention.
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.
Other objects and advantages of my invention _` 25 The present invention is concerned With the'
will be apparent from the accompanying descrip»-` gas-phase conversion of predominantly parafiinic
tion and disclosure.
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Y ;
hydrocarbons of comparatively low molecular
In the afore-mentioned copending application,
weight into more highly branched isomerie par
I have disclosed a broad process `for converting
afñnic
hydrocarbons and, in part, into saturated
30
saturated hydrocarbons into saturated lhydro
presence of hydrofluoric acid.
carbons of different skeletal conñgurationsand,
in part, ,of different molecular Weight by the ac-A
' tion of hydrofluoric acid. This process involves
several diñîerent types of chemical reactions.
hydrocarbons of. lower and higher molecular
Weight. I have found that, in- the presence of
substantial vproportions of hydrogen fluoride and
under' suitable conditions of temperature and
~>time, parafûn hydrocarbons of relatievly 10W
The predominating reaction types, as «deduced 35 molecular Weight, such as normal butane and/or
from a consideration of reactants, products, op
normal pentane, can be converted in high yield
erating conditions, and theoretical'oaspeots relat
ing to the invention, may be exemplified as fol
lows:
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“.40
to isomeric branched paraflins, such as isobutane
and isopentane. Further, I-have found that par
aiiins of higherr andlower molecular Weight can
also be produced -under similar conditions, con
currentlyV With the production of‘isomers, and
that the proportions and the molecular Weights
of‘s'uch products can be controlled by suitable
recycling steps; for example, ‘isobutane can be
vQ45 produced'as the major product fromone or more `
"$50
parafñns having four to ñve carbon atoms per
molecule, of which» at least four carbon atoms
are in a/ straight chain. `Still further, I have
found ' thatv relatievly Vnon-volatile material,
which is formed in small -proportions and Whichv
would' _otherwise _be deposited and carbonized
upon Vthe surfaces of the reaction zone, can be.
The ñrst two reactions, namely, reconstruction
to produce both higher- and lower-boiling par
removed .by scrubbing the reaction zone,v inter
mittently or continuously, with a liquid hydro
2,403,650
3
mixture in conduit I4 is passed to heating coil
I8, in which it is heatedto the desired reaction
temperature. The temperature should be so high
carbon which is relatively non-volatile at the re
action temperature.
In general, my investigations have shown that,
when a relatively low-.boiling paraffin hydrocar
bon material having at least four carbon atoms
per molecule, in a straight chain, is subjected
to the action of substantial proportions of con
centrated hydro?luoric acid under suitable reac
tion conditions, there results a mixture compris
ing propane, isobutane, normal butane, isopen
that the reaction mixture is in the gaseous con
dition; it usually may be within the range of
about 250° F. or less to 1000° F. or more. Usually
the optimum temperature is in the range of 400
to 800° F.; at lower temperatures, the conversion
is relatively slow, and at higher temperatures
10 excessive cracking and/or dehydrogenation oc
tane, normal pentane, hexanes, and higher-boil.
ing hydrocarbons. Any of these hydrocarbons,
especially if present in relatively large propor
about atmospheric to 5000 pounds per square inch
duction of iobutane and/or motor-fuel hydro
carbons from normal paraflins having four to
various possible alternatives.
From heating coil I8, the mixture is passed
through Valve I9 and conduit 20 to reactor 2|,
curs.
The pressure may be within the range of
or more; usually the optimum pressure is in the
range of 250 to 2500 pounds per square inch. At
tions in the original mixture or feed material,
tends to be converted to hydrocarbons which are. 15 low pressures, since the volume of reactants is
relatively large, a reaction -chamber of compara
originally absent or present only in small pro
tively large size is required; at high pressures,
portions. Thus, by separating out the desired
relatively expensive high-pressure equipment is
products and recycling the others, very high u1
timate yields of the desired products can` be ob
required. In any particular instance, the most
tained. In one specific embodiment, the pres 20 economical operating pressure may be determined
by -a study of the various factors involved in the
ent invention is directed particularly to. the pro
live carbon atoms per molecule.
As the catalyst,Y hydrogen fluoride may be used 25. wherein it. is maintained at the reaction temper
in the following ways: alone; with relatively small
`ature for a time sufficient to effect the desired
proportions of modifiers such as water, basic
degree of reaction. The reaction time may be
organic nitrogen compounds, and/ or salts; and/or
within the range of less than 1 minute to more
inv conjunction with solid contact` masses or sur'
than 300 minutes, depending chiefly upon the
faces, preferably those which comprise iron 30 temperature; for example, at 750° F., satisfac
and/or alumina, such as steel shavings, aluminaA
gel, bauxite, and the like.
tory conversions of normal butane are usually
obtained in 2 to 15 minutes, and at 650° F., in
Conversion stocks for the process- should be
15 to 90 minutes. When the time is short, for
composed of saturated hydrocarbons containing
example, less than about 10 minutes,v heating
preferably little or no unsaturated hydrocarbons; 35 coil I8 may be of such length that the reaction
they may comprise normal butane, normal pen
is virtually completed therein, and reactor ZI
tane, and/or higher paraffìns, provided that they
may then be by-passed or removed from the
are not so high-boiling as to make gas-phase con
ì system.
There is a tendency for small proportions of
version not feasible. Petroleum distillate frac- .
tions of undesirably low ostane number or of 40 relatively nonvolatile hydrocarbons, which are
volatility other> than that desired for> some par
formed incidentally in the reaction zone, to ac
ticular purpose may be used; such fractions may
cumulate and to carbonize or form coke on the
comprise either distillates as they ordinarily 0c
walls of reactor 2|. This action may be advan
tageously minimized by scrubbing the reaction
cur in the industry or fractions of inferior octane
number obtained upon removing constituents of 45 zone with a high-boiling oil, such as mineral seal
superior octane number from existing stocks.
oil, to absorb and remove the nonvolatile mate
rial substantially as soon as it is formed. The
The conversion stock may also comprise residues
scrubbing oil is admitted through inlet 22 having
from the application of selective solvent treat
valve 23 to distributing means 24 near the top
ing, azeotropic distillation, or the like to sepa
rate hydrocarbons having relatively enhanced 50 of reactor 2|. The proportion of scrubbing oil
value when separated -from each other.
is preferably from about'0.1 to about 1.0 times
by weight of the hydrocarbon reactants.4 Smaller
An understanding of some aspects of- my inven
tion may be aided by the accompanying drawings,
proportions are sometimes insufficient t0 effect
the desired absorption, and larger proportions
wherein Figure 1 and Figure 2 are flow-diagrams
showing diagrammatically two speciñc arrange 55 sometimes tend to interfere by the oil undergo
ing reaction itself. The reactor is so designed
ments for practicing my invention. Correspond
ing parts in each figure are designated by the
that the time of residence of the scrubbing oil
therein is relatively short, preferably of the order
same numerals.
In the embodiment of Figure 1, a hydrocarbon
of a tenth to a hundredth of the reaction time,
material, which for the sake of simplicity may 60 in order to minimize reconstruction or cracking
of the oil itself.
be taken to be chiefly or substantially entirely
Reactor 2I usually need not contain any pack
normal butane, is admitted through inlet II,
ing, or the like, so that the scrubbing oil simply
valve I2 and charge pump I3 to conduit I4,
falls from top to bottom as a spray; in some
whereinl it is mixed with concentrated hydro
ñuoric acid, which is admitted through inlet I5, 65 cases, however, especially those in which the
valve I6, and charge pump I 1. The proportion
reaction time is relatively'long, it preferably is
loosely packed With a suitable contact material
of acid may be Vfrom about 0.1 to 4 times or more
by weight of the hydrocarbon material; prefer
resistant to corrosion by concentrated hydro
ably, it is in the range of.0;2 to 2 times by weight
of the hydrocarbon material. The use of very
small proportions results in slow >or incomplete
fluoric acid. Among contact materials may be
mentioned metals, such as various steels, Monel
70
metal, alloys of chromium, nickel, magnesium,
conversion, andthe use of very large propor
tions causes a decrease in the production capac
and/or aluminum and the like, and granular sub
stances, such as alumina, bauxite, carbon, and
ity of the equipment.
The resulting hydrocarbon-hydrofluoric acid 75
the like.
'
The eflluent from reactor 2| comprises the re
amante.
6.
5.
action mixture,> chieñy of hydrogenfluoride andv '
In separator ’51,“the gas pliase'fromseparatorjü-
low-boiling hydrocarbons, which are partly vor
wholly in the gaseous condition; when scrubbing
with an oilis practiced, it‘ also comprises' this
oil, which is in the liquid' condition. Thiseñluent
passes from the bottom of yreactor .2| through
conduit 25 and valve' 26 to separator 21, in which
it is separated into a liquid scrubbing-oil phase
is separated -intotwo liquid phases', as by cooling ’f
and
gravitational l-means f. The
heavier - orl
hydroiiuoric -acid phase is recycled'through valve '
- 58 and c0nduit`54'to heating coil I8.r The lighter '
or hydrocarbon phase is passed through valve 59 A
and a gaseous hydroñuoric acid-and-hydrocar
and.- conduit 66» to vfractionating means 6I,
togetherk with the hydrocarbon phase ‘from
separator
bon phase, as by gravitational» or centrifugal 10
12.
'
.
In fractionating means 6I, these hydrocarbon
materials are fractionally distilled to yield ank
isobutane fraction and any other desired
The scrubbing-oil phase may be recycled
products. Light gases, such as methane, ethane.- through valve 28, conduit 29, and pump 30 to the
and the like, are preferably withdrawn from the l
top of reactor 2|. Preferably, however, at least
system, as through‘outlet 62 having- valve 63;:~
part of it is passed through valve 3| and conduit
Propane and hydrofluoric acid pass,> at`~~least
32 to fractionator 33-,Ywherein'it is purified, for
partly as" an azeotropic mixture, Vthrough valve
example by separation intovthe following three
64, and are recycled to coil|8 by conduit `65;'if '
fractions: '(1) a `minor lfraction comprising
desired, excess propanemay be 'withdrawnggas '
hydrocarbons boiling below the temperature in
reactor 2|, which may be withdrawn through 20 through outlet 62 and vvalve |53;v -Isobutane is
withdrawn through outlet 66 having -valve '61.
outlet 34 having valve 35 lbut which isusually
Normal butane is recycled through valve 68 and
preferably passed through valve 1I to conduit 40;
means.
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(2) a large fraction of relatively unchanged
absorbing oil, which is recycled through valve 36
~ and pump 30 to the top of reactor 2|; and (3) a 25
minor fraction comprising very high-boiling or
semi-solid material, which is withdrawn through
outlet 31 having valve 38'.î
V
, conduit 65. Hydrocarbons heaviervthan butane
Y may bel recycled with the normal -butane, espe-`
vcially if `the highest possible yield ofisobutane
1 is desired; but if desired, selected lor especially
valuable fractions may be advantageously` with-.
drawn; `for example, isopentane may be with-
The gaseous phase from separator 21 is passed f drawn through valved outlet 69, and/or material
through valve 39 and conduit 40, preferably 30 ~boiling above normal butane or above isopentane
ymay be withdrawn through valved outlet 10.
j
together with the lowest-boiling fraction from
yIt is understood that iractionating means» 6I.`->
fractionator 33, to partial condenser 4I, wherein
may. comprise whatever distilling columnsf'and;r
relatively high~boilin`g materials,- lfor example
auxiliary equipment 'appear necessary or conven-f
thoseboiling» higher than the hexanes, are con
densed: Suitable conditions may b'e such„as,~for 35 Aient for effecting the separations indicated. , ylîf >
example, a temperature of 450° F. anda pressure
`of 450 poundsper-square inch. If it is `desired to
use a lower pressure, a correspondingly lower
temperature is used; for example, at r100 pounds
per square inch the condenser temperature may
be about 300° F; The resulting mixed VVphases are
passedv through valve 42 and conduit y43 to
' desired, any of the fractions withdrawn may »be
subjected to one or more 'purification steps .not---
shown, such as, for exampla deiluorination by.
contacting with bauxite at a suitable temperature.
ÀIn the embodiment.l of-Figure 2, a hydrocarbon
material, which for the sake of simplicity may
be taken to bef chiefly or substantially entirely
separator 44, wherein they are separated by ~
gravity. v The resulting liquid phase, which
normal pentane, is `admitted through inlet II,
comprises cyclics, acid-solubles, and other mate
wherein it is mixed with> concentrated hydro
fluoric acid,. which is admittedthrough inlet I5,
valve I6, and 'charge pump I1.` Theresulting
hydrocarbon-hydroñuoric acid mixture is passed
to- heating coil I8, in which it is'heated. to'th'e
rial, for example hydrocarbons boiling in .the
hexane range and higher, is withdrawnthrough
outlet 4|5 having valve Mi., _The gas phase which
comprises chiefly hydrofiuoric acid, and hydro
carbons of up to about .six carbon' atoms per
molecule, is passed `through conduit 41 and ¿valve'
valve I2, and lcharge pump I3, toV conduit I4, y
i desired reaction temperature-. The `preferred`
proportions, of -hydroiluoricf facidëand the pre- l
ferred reaction conditions'for this embodiment
of my-invention aresubstantially the same as
In partial condenser 49, pentanes, hexanes, and
for‘the embodimentshown in Figure 1', and,
most of vthe hydroi‘luoric'acidL are condensed.
Suitable conditions may be such as, for example;` 553 previously discussed. The heated reaction mix
ture from coil I8 is passed to reactor2l, wherein
a temperature of 325° F.v and a pressure of'400
it is subjectedvto the desired reactionv conditions
pounds per square inch, or Ia temperaturev of'
225° F. and a pressure of 100- poundsper square f of temperature and pressure forl atime suilicient
to effect the desired. extent of reaction. If
inch. The exact optimum lconditions for any
particular case may be readily determined by 60 ¿.desired, reactor 2| may be packed with steel
turnings or.. otherv solid material suitable for
trial. The resulting mixed phases are passed
46 to second partial condenser 49.
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through .valve 59 and conduit 5I to separator `452,wherein they -are separated by gravity. _The
resulting mixtui'eof liquid> phases 'passeslthrough '
valve "53' to separator '12,` fröin'fwhi'ch >the heavier
aiding'in the lcatalysis of the reaction» Y. „
through conduit 2'5, having valve/26 to ~sepaatrator
21, wherein itis separated into two liquid phases,v
or 'hydrogen ñuoride phasë‘is recycled through
as by . @001mg and 'y 'gravitational'
valve 13 and conduit 54 to' heating coiljI8, rand
means. y
from which the VVlighter or"hydrocarbon`phase
passes through 'valve 14 to conduit 60; separators
- 52 and 12 are preferably so elevated in position
that the recycling of the acid phase is advan
tageously effected by gravity, without the use of
apump.
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' The _gaseousfphase from separator_`f5_2¿is Apassed,
through valve'55 and conduit 56 to 'separator '51.'
v
f The )eliiuent mixture from lreactorZ I =
or‘ centrifugal
‘The heavier or hydroñuoric ‘acidi- phase'imay be
recycled through valve 15 andjconduit 16 to'pump-I1.' Preferably,'hov'vever, at least Apart- '0f-it 'is
passed through v'alvc‘11 Àand conduit 18 tohfracl”
tionator 19, wherein it is separated -int'o‘the’fol
lowing two >'fractions :1 (1^) ` an overhead fraction `
comprising substantially a4 drous _hydrofluoric'v
acid with- small proportionsfof'light'hydrocarbò?sf
2,403,650:
this'material from the system, because it 4tends to
such as.- .propane-:and ebutane, which is. recycled
through valve 80‘and conduit `1.6 ‘.to pump VI1,'and
(2) a"v minor bottom .fraction comprising acid- .
carbonize- `inV the heater. and/or reactor.
VAlthough the isobutane product from fraction
soluble material, water, -`and hydrogenüfluoride,>
which is Withdrawn 'through outlet..8I‘-having.
purification steps-,. such as defluorination or the
valve
like, it usually need not be purified, especially if
82.
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.
ating means 85 may be subjected to oneor more
.
it'is‘to be used as feed to an` alkylation‘process
The lighter or hydrocarbon phase from sepa
rator 21 is passed through valve 83 and conduit 84
catalyzed by a hydrorluoric acid catalyst.
to fractionating means 85, wherein it. is fraction
ally distilled to yield an isobutane fraction and
Some aspects of my'invention are illustratedA
in the following examples, which are illustrative,
any other desired products. Light gases, such'as
but not necessarily limitative, of the invention.
methane, ethane, and thev like, are! preferably
lEzrampze I
withdrawnfrom the system,- as through> outlet
86 having valve 81._ Propane and hydrofluoric acid.
pass, ~ at least partly as an' azeotropic mixture, '
through valve 88, and are recycled to `coil I8 by
cond-uit89; if desired, any excess propane may be
withdrawn, as through outlet 8.6 and' valve 81. Iso
butane is withdrawn through outlet 90 having
A hydrocarbon stream consisting of substan
15 itially pure normal'butanel is subjected to the ac
tion of 50 per cent of its weight of concentrated
hydroiluoricv acid in aprocess similar to that de
scribed in connection with Figure l. The reac
tion temperature isab'Out 650° F., the pressure is
valve 9|. Any normal butane is usually prefer 20 .about '150 pounds per square inch, and the‘reac
ably recycled through valve 92 and conduit .89.
tion-"time is about 30 minutes. Reactor 2 | is
Hydrocarbons heavier than butane may be re'
‘
packed'fwith steel turnings; and about 5 per cent,
byweight of hydrocarbon treated, of a high-boil
cycled=with the normal butane, especially if the
highest possible yield of-isobutane is desired; but
ing absorber' oil ~is passedv continuously through
if desired, selected or especially valuable fractions 25 the vreaction Zone' to prevent coking'up' of the re-`
may be advantageously withdrawn. For exacrnple,~
actor. yUnder theseconditi'ons the ultimate yieldv
isopentane may be Withdrawn-through outlet 93 '
of isobutane‘is about 75 per cent by weight of the `
having Valve 94; normal pentane is preferably
normal butane feed. Of'the other 25 per cent,
about 10 per centis convertedto` propane; and
recycled through valve 95 and conduit 89;v and
material boiling above normal pentane maybe
withdrawn through. outlet 96 havingy valve 91.’
Fractionating means 85 may comprise Whatever
distilling .columns >and auxiliary ’equipment are
aboutV 15 per cent.: to heavier hydrocarbons.
A hydrocarbon stream 'consisting mainly of nor
mal pentane is rsubjected to the action 'of about 70
necessary or convenient for effecting the separa
tions indicated.
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35
If desired, any ofthe fractions Withdrawn from'
fractionating -means 85 may be passed through
per cent of its 'weight ofï' substantially 'anhydrous
hydrofluoric acid ina process similar to-that de
scribed in connection With Figure'Z. *The reac
one ormorepuriñcation steps. 'For'example, the
tion temperature is about 700“ F., the pressure
fraction boiling above normal pentane' may pass
is> about 1000 pounds per square inch,” and the
through valve 98y and conduit 99 to fluorine re 40 reaction time is about 20 minutes. >Pentanes in
mover |00, which contains a ‘contact lmass having hydrogenation and/ or dehydrogenation prop
the product arer recycled. " Under these condi
tions, the yield `of motor-fuel hydrocarbons hav
ertles, such> as bauxite, alumina, or other similar
ing >6 or more carbon atoms per molecule -is about
catalyst.y Usually »suitable operating conditions”
25 per cent by weight of the material charged,
are a temperature in the range of '75 to 400° F. 45. and the yield of isobutane is v»about 60 per cent;
and a space velocity inthe range of 1 to 50 vol
the remainder- is 4'converted‘to propane and to
umes of liquid hydrocarbon material per volume
material boiling above the motor-fuelrange.
of catalyst per hour. Under such conditions,
which maybe particularly selected in accordance
Example III`
with the results of a trial for the particular case
organically combined fluorine is substantially com
In a batch procesa-normal butane Was treated
in a steel reactor with 3 -times its Weight of an
pletelyfremoved from the hydrocarbon material,
which then .is passed through valve IOI and
conduit" |02 to fractionator |03 for separation
hydrous hydrofluoric acid..~ The -‘maximum tem
perature was'about 515°
the maximum pres
sure was about' 230- atmospheres,- and «the time
A substantial 55 ,latthese conditions was about'40 minutes. About
fraction comprising motor-fuel hydrocarbons may
two' hours was y:required to. heat the reactor to its
into any desired final fractions.'
maximum: temperature. The reactor was cooled,
andthe contentsy Were withdrawn for analysis.
By fractional analysis the recovered> hydrocarbon
be withdrawn through outlet |04 having valve |05,
andav minor'fraction comprising hydrocarbons
boiling -above the motor-fuel range ‘may be with’
drawn vthrough outlet |06. having valve |01.
60
~The volatility of the motor-fuel product is Iad
vantageously controlled by adjusting the propor
tion of relatively light constituents, _any excess
of which is recycled from fractionating means 85.» 65
For example, if a relatively volatile motor fuel is
desired, -less of these light constituents is.-re-I
cycled„and more is left in the motor-fuel frac
tion. vSome adjustment is alsopossible by con
trolling the proportion of relatively high-boiling 70
constituents which is withdrawn from the bot
tom of fractionator |03. -If desired, part or all
In a corresponding continuous process, in which
of the above-mentioned high-boiling constituents
reaction conditions are comparable but in which~
maybe recycled, by iheansv not shown, to pump
recycling gis.»practiced,> the major-product With
I3;` usually, however,V it is preferable -to remove 75 . drawn .fi.s.~fis,ebutanei.íisppentane and/0r higher»
10
cate vthat, isopentane canl be `converted .to any>
desired extent> into relatively heavygmotQr-ffuel
-hydrocarbons, whereby control ofthe' volatility
of relatively heavy, products may be advanta
Iboiling hydrocarbons maybe also" withdrawmhut
if desired,`.they maybe recycled to increase the
»ultimate yield of isobutane.
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’
Example IV
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"_
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,
geously obtained inthe manner' generally
In abatch process, normal pentane was treated
scribedherein.
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1
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f
,
,
4
My invention provides a new 'process for con-l
in a steel reactor with twice its weight of con
centrated hydroiluoric acid. The maximumtem
perature, reached in about one hour after start
ing the heating, was 572° F. This'temperature
was maintained for -30 minutes; then the reactor
was cooled rapidly, and the products were with
drawn for examination.> On a normal pentane
>»vertingnormal butane and/or, pentane to iso
butane.
It is applicable valso to the'production
of isopentane, forexample by the conversion of
normal pentane and/or heavier parai’dns toiso
pentane. yIt would also .be possible to lconvert
_free basis, theproportions of the various prod
isobutane and/or isopentanetoanormal butane
and/or normal pentane, respectively, by thisv in
.ucts were asA follows:
vention, if _a need for such a _conversion should
Product: >
.
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Y
_
arise.A Motor fuel of controlled Volatilityjcan be
vproduced in substantial propOlftions'as a product
ofmy process. VMy invention comprises ?also a
novel
means for preventing coking up of reaction
18.6
v20 chambers used in the process. Furthermore, it
2.6.4
Weight percent
VYPropane>~ _________ ..-'_____‘_ _______ ..i__
lIsobutane f'
'
-_
-'j
~
12.4
29.8
` f'Normal butane___'_-_ ____ __ _________ __
, ~'¿ _,lîsopentane ________ _-‘_,_‘ ___________ __
Vfj"‘V'He,xar1es'____'..; ______________ _;...'.____'
l
provides aA simple method of‘ separating` heavy
acidfsoluble material from hydroiiuoric acid
8.2
Higher-_boiling f______'_____.r~___;innr.' A 4.6
which is to be recycled.
~
_ _ There are many modifications of my process,
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"2100.0
-apparent v‘from lthese* data that, _in a icor-
.25. of which only a few are described in this specifi
cation. Hence, it is not intended thatmention
_responding continuous process, by recycling un- _
Íherein `ci? specific apparatus, materials, condi
.; desired products-_especially propane and/or _nor
¿ tions, purposes, _or the Ylike should unduly limit
_ma,1~.hutane,1.ri0rma1 pentaneecan V.be converted
high` yield» to isobutane Yand/Q1’ ,isopentane
and/or motor-fue1hydrocarbons¿
g
l
the scope of my invention. In the specific em
30
.bodimentsdescribedit is understood that addi
vtional‘equipment such as pumps, valves, coolers,
fractionators, or the like, such as are well-known
ï»In 4asteel bomb, no?malbutane wassubjected '
to those skilled in l.the art, may be` used wherever
needed or convenient. ~
Y
Y
Y,
>to the-action` of twice its Weight of concentrated, 35
_,¿hydrofluoricacid at a maximum temperature of
_ ¿LA process Ífor isomerizing 10W-boiling par
-~3._5_6°_>F. and a pressure of 3700 poundsV per square
amnjhydrocarbonsjof at least >four carbonvatoms
per moleculein a straight chain to form low~
finch for a, period of three hours. ',I‘he bomb'was
boiling isoparaflins, whichcomprises subjecting
cooled, and the vproducts were withdrawn. _The
.Èhydrocarbon material recovered had the follow 40 in a reaction zone sucha parañìn to the action of
¿_Iclaim;
.,iñsïcomvqsiüòa.
'A
"
`
-
'
hydrofluoric acid as the sole effective isomeriza
tion catalyst, in an amount from _about 0.1 `to
'
, 4 times by weight of the hydrocarbon material,
under an elevated vtemperature and pressure such
45; that said paraffin and hydroiluoric acid arey in
gas phase, passing a minorl amount of a heavy
voil through said reaction _zone .as a liquid to__ab-
sorb reaction products of high molecular Weight
andv minimize carbon and tar formation„pass-
" fAlthoúg'hg'fi'n this' exampm, theréactipn condi
eilluents of said reaction zone to a first-sep
tions'were obviously 'very unfavorable', an appreci--f’y 50,_ ing
arator andremoving as a liquid said heavy oil
"able reaction did-occun" the conditions used "are
and absorbed constituents, >»removing falso fromYtherefore, vconsideredy tojbe'within the broadest
»said I'lrst separator as a Vgasa mixture of low-boil
scope of-this invention.
~
' " »
ing hydrocarbons and hydrofluoric acid, subject
Ezramp‘le VI
f55 ing said gas to partial cooling and condensation
‘
Isopentane and about 60 per cent of its weight
of >concentrated hydrofluoric acid were'allowed to
" stand Vin a steel bomb for fourweeks at ajtem
’perature ofV _175°_F.j Then the products vwere
withdrawn, and the resulting hydrocarbon ma
lí terial was found to have approximately the fol
-lowing,composition:
'Päoductzff
~
__ _
_
'j
'
_
Y
`
,l ,Mol percent
to liquify hexane and heavier hydrocarbons and
removing the resultant liquid from the process,
subjecting ythe remaining gas to further partial
' cooling and condensation to liquify ’themajor
60Y portion of hydrofluoric acid, and separating same
_'ìfrorn.v uncondensed gas, cooling and condensing
fs'aid uncondensed _gas to form a liquid hydro
ñuoric acid _phase land __a liquid hydrocarbon
phase, >passing said liquid hydrocarbon phase to
65 >a fractional distillation andY recovering there
Butanes (mostly isobutane) _____ __‘__f_
8.6
' Elsopentane _____ _V_`_ ____ _....___K__^..’..__"_
69.6
from low-boiling isoparaiiins.
11.5
_2_.LThe process of claiml, in _which said elevat
ed temperatur-_eis in the _range of 250to 1000?` F.
3. The process of claim l, inwhichsaid ele
Hexanes and heavier...... __`...;_'____;_
î'Althoug'h, inthis example» the ïsòpéntane- was
_ `mostly.inthe liquid phase because of the rela
?,tively low temperaturafthe results show thatiso
.Qlìentaneban betreated land/or recycledjto give ~
_
_
,
_,
70v vated temperature is in the ranges of L1to0-800" F.
4. The process of claim 1, wherein the reac
_ _tion zonecontains _a solid contact mass.
_
. „ _5.„The‘process' of; claim, Lin, which Said' par
`Vaiiñn is__no_rmal pentane Vand'in which saidisop'flir‘
fappreciable .yields of. isobutane; ' also, .they indi-. 75, amnsouproducedis;isobutane. ,„
‘
V2,403,650
~
I2
prising such a low-boiling paraflinand hydrogen
iiuoride as thesole isomerization catalystthrough
6. A process for converting low-boiling paraf
fin hydrocarbons of at least four carbon atoms
per molecule in a straight chain to form low-boil
ing isoparafiins, which comprises passing such a
paraiîin in admixture with hydrofluoric acid as
the sole effective conversion catalyst, in an`
amount from about 0.1 to 4 times by Weight of
the hydrocarbon material, through a large lver
a reaction zone while at an isomerization> temper
ature in the range of .about 250 to 800° F., main
taining said mixture in said reaction zone for a
time suiiicient to isomerize a substantial amount
of said parai‘rin forming an isomer thereof, cool
ing and effecting a partial condensation of eillu
ents of said reaction zone to condense and remove
as a liquid heavy cils, Subj ecting remaining vapors n
‘ tical reaction zone, maintaining the mixture in
said reaction zone in gas phase under an elevat
ed temperature and pressure for a time to effect
a substantial conversion of said paraffin to form
to Vfurther cooling and effecting a p'artialconden
sation thereof to condense a major part of the
hydrogen fluoride and of remaining Ahydrocarbons
heavier than `butane, separating from the last
said partially condensed ï'mixture liquids so
formed and uncondensed vapors, separating from
low-boiling isoparafiins' including at least one
isomer of said paraiiin, introducing at the top of
said vertical reaction zone a heavy hydrocarbon
oil which remains in liquid phase under said con
version conditions to absorb reaction products of
high molecular weight and minimize carbon and
tar formation, passing eilluents of said reaction
said liquids liquid hydrogen fluoride and liquid
zone to a first separator and removing as a liq
hydrocarbonY as separate materials, subjecting
said uncondensed vapors to V‘additional cooling
and condensingto form a second liquid hydrogen
20
uid said heavy oil and absorbed constituents,
passing said liquid to a fractionating meansand
removing low-boiling hydrocarbons absorbed
ñuoride phase and a second hydrocarbon-phase,
therein, removing a gas from said ñrst separator
ing the last two said hydrocarbon phases and
combining Y_said liquid hydrogen fluoridephases
and passing same to said reaction zone, combin
and admixing said low-boiling hydrocarbons 25 subjecting same to fractional distillation, recov
ering from said fractional distillation normally
with said gas, subjecting the resultant mixture
gaseous-para?lin hydrocarbons and a -minor
to partial cooling and condensation «to liquify
amount of hydrogen fluoride and passing same to
hexane and heavier hydrocarbons and removing
the resultant liquid from the process, subjecting
the remaining gas to further partial cooling and
condensation to liquify the major portion >of hy
dro?luoric acid together with some pentanes and
said reaction zone, and recovering also Vfrom said
fractional distillation low-boiling isoparaflins as
returning said hydrofluoric acid phase to said re
action zone, cooling and condensing the last said
elongated verticalreaction zone in vapor phase
a paraffinic hydrocarbon material comprising
products of the process-
Y
'
'
’
'
10. A process forv converting a low-boiling par
aflin hydrocarbon havingat least four carbon
hexanes, and separating same from uncondensed
atoms per molecule »to otherlow-boiling paraf
gas, separating the resulting liquid into av hydro
iiuoric acid phase and a hydrocarbon phase and 35 fins, which comprises passingtothe top of an
such a low-boiling paraffin and hydrogen -iiuo
uncondensed gas to form a hydrofluoric _acid
ride as the sole eiïective catalyst?in an amount
phase and a hydrocarbon phase and returning
said hydrofluoric acid phase to said reaction 40 between about 0.2 and about 4 _times byvweight
of the hydrocarbon material, maintaining the re
zone, combining the two last said liquid hydro
sulting gaseous mixture of hydrogen ñuoride and
carbon phases and passing same to fractionat
paraflinic hydrocarbon material in said reaction
ing means, and recovering from said fractionat
>zone ata conversion temperature between about
ing means low-boiling isoparafiins so produced.v
.7. The process of claim 6,'wherein the propor-l 45 250 and about 800° F. and undena superatmos
pheric pressure for a reaction/time suñicient to
tion of absorbing fluid is inthe range r0.1 tol
form other low-boiling paraflin hydrocarbons in
times by weight of the Vhydrocarbon material
cluding at least one isomer of said low-boiling
vtreated and its residence in the> reaction zone is
parafiin, injecting into the top of said reaction
not greater than one-tenth that of the Vparaffin
undergoing
conversion.
'
n
8. A process for converting a low-boiling par
>aiiin having at least four carbon atoms per mole
cule to form other low-boiling parafñns, which
comprises passing a gaseous mixture comprising
such a low-boiling paraffin and hydrogen iiuoride
as the sole conversion catalyst downwardly
through a reaction Zone while at a conversion
temperature in the range of about 250 to 800° F.,
maintaining said mixture in said reaction zone
'
zone a liquid hydrocarbon material in a manner
y such as to scrub the inner surfaces of said reac
50 »
tion zone and maintain the same free of carbon
aceous deposits, said liquid hydrocarbon mate
rial being relatively nonvolatile at said reaction
temperature and passed through said reaction
zone at a rate . such that its residence time
therein is'not greater than 0,1 times said reaction
time, and recovering from the bottom of said re
action zone hydrogen fluoride, >reaction products,
for a time sufficient to convert a substantial 60 and said liquid hydrocarbon material.
11. The vprocess of claim 1.0 in which saidma
terials eiliuent from said reaction zone arepassed
as a single eii‘luent mixture- to a separator, sep
paraiìn, concomitantly passing downwardly
arating therefrom a liquid phase comprising said
through said reaction zone in liquid phase a:
heavy oil to absorb-reaction products of high mo 65 lliquid hydrocarbon material and a gas phase com#
prising hydrogen iluoride and paraiîînic reaction
lecular weight and minimize tar and carbon for
amount of said parailin forming other low-boil
ing parainns including at least one isomer of said
mation, said oil being passed through said'zone
products, returning a‘portion» of said liquid phase
tothe top of said reaction zone, subjecting a
>further portion of said liquid phase to purifica
conversion, and separating from effluents of said
reaction zone low-boiling hydrocarbons produced 70 tion to remove volatile material and liquid im
purities, recovering >a puriñedliquid hydrocar
` bon material and passingsame to the top Iof said
9. A process for isomerizing a low-boiling
paraffin having at least four carbon atoms per
reaction zone, combining said volatile [material
molecule to form other low-boiling paraffins,
’ .with said gas phase and .recovering therefrom a
at a rate such that it undergoes substantially no
therein.
’
'
which comprises passing a gaseous mixture com
hydrocarbon 'fraction comprising an isoparamn
2,403,650
13A
,
»
produced in said reaction zone as a product of
the process.
12. The process of claim 10 >in which the reac
tion zone is packed with granular alumina.
13. A process for converting a low-boiling par
afûn having at least four carbon atoms per mole
cule to form other low-boiling paraiñns, which
comprises passing a gaseous mixture comprising
such a low-boiling paraffin and hydrogen fluoride
as the sole effective conversion catalyst, in an
amount from about 0.1 to 4 times by weight of
the hydrocarbon material, downwardly through a
reaction zone While at a conversion temperature
in the range of about 250 to 800° F., maintaining
Y
14
said mixtureínsaid reaction zone for a. time suf
ñcient to convert a substantial amount o! said
paraffin forming other low-boiling paraiïins, in
cluding at least one isomer of said parañin, con
comitantly passing downwardly through said re
action zone in liquid phase a heavy oil to absorb
reaction products of high molecular weight and
minimize tar and carbon formation, said oil be
' ing passed through saidzone at a rate such that
it undergoes substantially no conversion, and ,
' separating from eñluents of said reaction zone
low-boiling hydrocarbons produced therein.
FREDERICK E. FREY.
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