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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 o „i 2,403,650 , ¥ 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. _ , 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. . , » . 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. « ~ 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: " Y » . “.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. . n Y (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. ` ' , 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. » ^ ' 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. f . ; . f . . 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. ` ' 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. ` i _ K ’ Example IV - , "_ ` ’ , geously obtained inthe manner' generally In abatch process, normal pentane was treated scribedherein. _ 1 . 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: > . ~ 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, ' n l ' "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.