Патент USA US2404897код для вставки
vJuly 30, 1§46„ ` Y v w, N, AXE' - \ _2,404,897 ALKYLATIO'N PRocEss Filed Nov.' 24, 41942 ATTORNEYS 2,404,897 Patented July 30, 1946 UNIT-ED "STATES PATENT ¿OFFICE :ALKYLATION PROCESS “îWilliam‘ Nelson Axe, . Bartlesville, Okla., _ assignor tto ‘Phillips Petroleum Company, a corporation Application November 24, 1942,2‘Serial No.î466,‘7.62 2 t have been found‘inadequate whenappliedtoiso This invention relates to the synthesis of high octane-number isoparan‘lnic hydrocarbons Ífrom lower molecular weight isoparañins andethylene. More specifically, thisinvention Vrelates .tothe paraiiin-ethylene reactions. ‘ ,Insofar astheîprior-,artis concernedaanhydrous aluminum-chloride activated -With hydrogen chlo ride - appears 4to '~ be .the . best catalyst . described »as alkylation of low-boilingisoparafûns with ethyl- . applicable `to >alkylation rWith -ethylene and lits enequnder moderate -conditions of temperature higher homologues. However, ythere are =. certain and pressure in` the presence of -a novel alkylation valid objectionsito the-.use„of 4this catalyst com bination -among which ythere 4may `be mentioned; isomerization- of> theÍ isoparai’linsy and auto destruc catalyst. Inone specific modiñcation‘this inven tion relates to an improvedprocess ,for the» utiliza tion Íof ethylene-in the falkylationof isoparafñns .1,0 tivewalkylation `forming high boiling .products suc-has isobutane to,;produce-isoparan^in fractions of :exceptional V-value as :component-s of 4,aviation fuel. ‘The `introduction ' of lalkyl groups 'into . the . ben zene .ring‘ in the `presence fof the @various Friedel Crafts `type catalysts is'a’classic‘reaction'in or ganic chemistry. More ¢recently alkylation, in volving‘isoparaftinsand oleñns, has been -extended tothe ñeld of aliphatiochemistry as a 4result of sludge materials. Thus with oleñns-aboveethyl ene in the homologous series attempts to .mini L15 mize these undesirablecharacteristics have .been madehy 'operating `ai‘rtemperatures `below .32° F. Even «with .the ,less lreactive ethylene, `a lack- of specificity »at .room-temperature Ioperation lhas been reported lor .the >allcylation of `butano with ethylenefinlthathexanes so .produced amounted .toonlya minor proportion ofthe total .alkylate andthe.difisopropylfraction made up- only. a-still smallerzpen cent .of the total alkylate. _'It is `.the `object <cf` the _present .invention to N) TA providea `process 'for >the alkylation of isoparañ‘lns the demands for saturated hydrocarbon stocks of high octanerating in" thema-nui acture‘of: avia tion gasoline. Even `more recently :recognition of the importance of tthefso-.called “rich-mixture rating” of aviation fuelszhasagiven addedlimpetus to the Asynthesis of specific hydrocarbon types. Thus itihas been` foundîthat .certain gasolinas of requisite octane-rating .are deficient `in perform ance `*under conditions involving‘the high ',fuel air ratios »often »demanded yin rmilitary air-'craft 30 operation. -Alkylated Aaromatic ' v*hydrocarbons have Ybeen found `to `improve ¿the rich-mixture in general, vand ,isobutane in particular, .with ethylene employingan improved catalyst-,capable ofpperating with .a .lhigh degree of specificity undcroperating conditions conveniently attained in industrial practice. The specific action 'of my novel catalyst will .be illustrated '.by >subsequent .data showing the ‘.:total alkylate to have an iso >characteristics of high-octane gasoline, `but tbe hexanecontent 4ranging from `50.tc 80 volume per cause of »their low volatilityîthequantity o'fsuch cent With pure `di-isopropyl comprising 93 to 95 additives that >can'be incorporated `into the‘blend 35 .per cent ofthe isohexane fraction. Other ob is necessarily limited. -On the `other hand, the jectsand advantages will be apparent `from .the isoparafñn, 2,3»rdimethylbutane ‘ihereinafter :re accompanying disclosure and discussion. ‘ferred toas `di-isopropyl, lis Ucharacterized .by :its This application‘is a continuation-impart 'of goed >rich-mixture rating and» a volatility permit my. copending application Serial‘No. ‘459,985,.filed ting v(-:oncentrations»of 10 per'centland higherlin 40 September 28, 1942, in Which‘isbroadly disclosed ñnishedgasoline blends. ‘ ' the use of my preferred catalyst‘in the alkylation -`’Except -ifor nearly negligible -quantities 'labori of isoparaflins With oleñns. ously Visolated `from> natural gasoline,` ¿li-‘isopropyl The catalyst composition of ‘this invention .is is obtained primarily as'aisyntheticfproduct. i The preparedby treating phosphoric acid of variable Ymost-convenient `'direct «synthesis fof K hexane thy Water content with anhydrous boron fluoride until complete saturation has been realized. With 100 drocarbons 4invnlvesitlie ¿alkylati'on of ßisobutane with ethylene. Although :the ,alkylationfof ‘iso per cent phosphoric acid substantially one mol parai’ñns „in general and isobutane in particular of boron iiuoride is absorbed per mol of acid While in the case of aqueous solutions `both the phos with _oleiins ¿of three or Vmore carbon .atoms is phoric acid and water absorb boron iiuoride ap now a Well 4established practice, the utilization of ethylene `-in reactions of .this type _has Abeen proximately mol for mol. 'No theories are >ad extremely difficult. Thus .certain -acid catalysts vanced as to ‘the chemistry .involved in the cata lyst preparation, but >it .is `presumed that a ‘type such as sulfuric and phosphoricacids, Whilerela tively .quite :elîective ,in alkylation reactions .in VQlvlng .olefìns «of three lorlmore carbon atoms, of chemical combination often referred to as a complexer addition compound'has resulted. "The 2,404,897 3 complex derived from boron fluoride and Water is usually designated as boron ñuoride hydrate. Where 100 per cent phosphoric acid is concerned, the empirical representation of its complex with boron ñuoride is HsPO4.BFs. In the same man ner` catalysts prepared from aqueous phosphoric acid and boron fluoride would be a mixture of the following components: H3PO4.BF3 and HzOtBFa. The boron fluoride-orthophosphoric acid cata lyst is prepared by adding gaseous boron fluoride to the acid, or an aqueous solution thereof. The resulting reaction is exothermic and the rate of boron fluoride addition is usually controlled to 4 total alkylate. Alternately, if desired, the alkyl ate may be fractionated to separate traces of high boiling material and employed directly as a blending agent in the preparation of high oc tane aviation fuels. A specific preferred embodiment of the process is illustrated in the fiow'diagram which shows diagrammatically an arrangement >for process equipment for the continuous alkylation of iso~ butane With ethylene to produce and segregate products valuable as blending ingredients of av iation gasoline. Ethylene and isobutane are withdrawn fromsuitable sources, represented by gether with external cooling of the addition prod storage tanks I and 2 and passed by means of uct and/or products to avoid temperatures much 15 pump 3 to feed tank 4. 'I‘he isobutane-ethylene above 200° F. Saturation of the acid solution and completion of the preparation is denoted usually by escaping boron fluoride fumes or by a blend is fed to reactor 6 by means of pump E. Reactor 6 is equipped With means of agitation such as motor driven agitators, jet mixers, a constant specific gravity. ` recirculation pump, or the like, and line 3@ may The presence of boron fluoride hydrate in the 20 be used, when necessary, to drain they reactor. catalyst composition is not essential to the catal Provision is also made for removal of the heat of ysis of the isobutane-ethylene reaction although reaction by conventional design. An emulsion it may co-operate and/or promote the activity of of hydrocarbonv and catalyst is continuously the H3PO4.BF3 complex. On the other hand Withdrawn from the reactor to catalyst sepa~relatively large percentages of the hydrate do 25 rator 'I. Becausey of the relatively high specific not interfere with this reaction as may be the gravity of the catalyst, separation by gravity is case where alkylation of the higher molecular rapidly effected vand a portion of the catalyst weight oleñns are concerned. Since the polymer phase is drawn 01T into tank 8 and a portion is izing activity of the hydrate is well known high through line I2 for recovery of boron percentages are to be avoided with oleflns such 30 discarded fluoride. Make-up catalyst is provided by the as the butylenes. However, with regard to ethyl introduction of boron fluoride from line I3 and ene alkylation a wider latitude is possible since partially saturated acid delivered from the ethylene exhibits a much greater resistance to washer I4 by line I5. Maintenance of a catalyst polymerization. The phosphoric acid employed may be in con 35 phase completely saturated with boron fluoride is the function of tank B. From tank 8 the catl centrated form, ranging from the 85 per cent alyst is delivered to tank 9, from which itis acid of commercial grade up to about 100 per pumped backthrough line IU by pump. Il, 'into cent or more of HaPOr; or aqueous solutions con reactor 6. If desired, a portion'of the catalyst taining as little as 20-40 per cent H3PO4 may be may be directly recycled from separator 'i through employed. For most applications the moderately 40 line 32. ' ` concentrated to concentrated acid is ordinarily Eiliuent hydrocarbon is passed from Vseparator preferred for several reasons: (1) a considerable 'I into washer I4 where intimate contacting with economy in boron fluoride consumption per vol phosphoric acid, introduced through line i5, re unie or per unit weight of catalyst is effected; (2) less boron fluoride is carried away with the 45’ moves the last traces of boron fluoride. The acid in the Washer also serves as the feed for the prepr eiiluent hydrocarbon; (3) the production of a less aration of fresh catalyst. An auxiliary Water corrosive catalyst; (4) a better recovery of boron washer or a clay tower, not shown, may be em» ñuoride from spent catalyst by convenient means. ployed immediately following the acid Wash to The unique action of aqueous phosphoric acid remove any entrained acid. The hydrocarbon in the preparation of my preferred catalyst is 50 stream then is passed through line I'I into esta» demonstrated by the fact that other mineral acids bilizer I8 where the isobutane is taken overhead such as'sulfuric acid and hydrochloric acid fail and returned to storage via line I9. Any uncon to result in catalysts of comparable activity even densed gases such as ethylene or ethane, etc., though the quantity of boron fluoride hydrate may be separated and vented either from the may be appreciable. This is especially true of stabilizer through line/39 or from auxiliary gas sulfuric acid which appears to have an inhibiting stripping equipment (not- shown).- The stabi effect on the catalytic activity of boron fluoride lized total alkylate is passed through line 26 into complex compounds. the fractionating column 2| where a Vpentane I have discovered that the alkylation of iso fraction is removed as an overhead fraction and butane with ethylene to produce a high yield of passed to storage throughline 22. The kettle di-isopropyl is smoothly and eñîciently promoted by catalysts which comprise saturated solutions of boron fluoride in ortho phosphoric acid of variable Water content. While the alkylation process can be carried out under a Wide range of mild conditions it often comprises the contacting of controlled molar proportions of isobutane and ethylene with the liquid catalyst under condi~ product, now comprising hexanes and heavier, is charged to fractionator 24 through line 23 and isohexanes, of which di-ísopropyl is the major component, are taken overhead leaving heptane and heavier as the kettle product to be charged to fractionator 2l. A naphtha fraction in the gasoline range and of good octane number and lead response constitutes` the overhead product. stantially complete ethylene utilization. The hy 70 The small amount of heavy alkylate is Withdrawn through line 29 for utilization elsewhere. drocarbon product mixture is continuously sep arated from the catalyst and the alkylate is sep When the illustrated lseparation and concen arated from unconverted isobutane by means of tration of di-isopropyl is not desired, the sta fractional distillation. Subsequent distillation is bilized, substantially C4.-free alkylatevmay` pass tions that produce a high degree or even sub1 employed to separate the di-isopropyl from the through line 3.! to fractionator 21, wherein the t _ fascismo?, A ` _small amounts of heavy alkylateffmayîïfbe‘fsepa- Tïïß ‘rature’ and >the.',pressures:desirable inzxsìibseqúent _hydrocarbons~‘are"separated-fprior’toffractiona- îäñ Often USed- Regardless 0f Operating Conditions :Ltion of theja-Hçyiatemane-»manner«eeseiibed gfinßeeneraLjSufñeìent?pressureîshouldßbe applied _ Although |‘the’ “cata-lystcofr-th'ls ‘- invention *Í'ëdis- ‘m "Offler t0 insure 'il-îqliîd‘flehase‘ Operation i-infthe _ The_»ifalkylate sr-p'ro'duced ï' from ‘ff-is'obutane wand _.-ßperabingf conditions; „fwhemisobntaner‘fanœ ethyl- 31’0 »ethylen ' 'by the' iboronl-Tluoridefcatalyst «composi _;_formance~ ¿_The ¿most important variablesïare; --ia'll'ï ‘boiling orange'.fofiA¿approximately?0821-350"ÜF. Contact time, temperature, isoparañin-olelìnra- `*after *separation ß of ‘f‘excess >L>isolo‘utane.` “Z'I‘he ntiosantlrhydroearhonecatalyst-î-ratio. :Otherwar- `SI5 ¿ÈÁS‘I‘M‘ e’focïztane I'I’aïtirie-*cif` î ther-’.totalgfalkyiate@may mames»whiahf'arenargelyf. dependent on the-:mode «_ tropeuationware:«degreeeof'rdispersion_iofneatalyst imthëhydmcmbon„Impressum_ _ _ very from about 89.0 to 90.0;for’ìhi‘eher.«Withfa lead response Such that the addítîoneohliccfiof j rtetraethyl leadiis -sufûcientto giveaailoûloctane I_n general it maybe ‘said that contact times mumbel‘ 01‘ hîgheï‘_ for ethylene conversioïmust be somewhat longer-51,20 `J‘ractional .distí11ation`_ A,of _ ithe Etotal f_alkylate "_thanîfori?zhe'highergoleñns «Wherei-the .Contact t:orsresidence ftimeîinatherreactor is.` short», incom- from a iiypîßallfrllnlfrevealsrîtheifollowing-«Cûm ì‘posîtionr lïiplète:fconversionnof:the‘ethyleneenrayfresult-'even ‘_ vowìthlîa“fullyzactiveacatalystfand- involve;»either »'¿ÍSODEIIMDC _ ` _ _ f ,VOL vperscent _ _¿„.6.5 ë‘loss rorîlrecyclîng"ïof‘the;ethylene. -,--Deñning the225 --fHeXëlIleS contact time as the following ratio: A_IéIJeìJtanes _ c anes _m _ `~fil-0 ___ ‘ 3.5 _ ' ` Y*16.5 ‘iNonanesfarid heavier __________________ _112,5 @may «resultlin älk'ylate ' "dellcient ' in ‘quality A ‘be‘rmaintainedrinïi-»thef‘reactorwmay'fvaryziwidely 6:, phoric acid to give`1`00"per"c`ent phosphoric aeìd‘ impending@ aheoéliî‘cieney offseontactíngßand »',Whichll-wasuëthenfsaturate'diwith anhydroushoron "tl-le‘ratex of’ '?lowï‘throughlthei reaction zone. \--«With iîílu'o?ide. " The oalkyl'ation .treaction «maw-»carried *reasonably '-'goo'd La'git'ati'on-anratio :of aboutfz'four '-'vblumesof hv‘dreoa?oonß‘per volumeeof-f'eatalyst r:“o'1`1t~=as»fï»a f_‘continuons‘eproeess‘;under"z250~ îpoun'ds A~fea-gerpressm'e. 'rheiliydrocarbon :_phasefnn the vi-is‘usually>ìa'deq-u-e‘nze,‘~‘although higherrorf-lowerfra- 57o reactor amounted to four volumes per volume ßiOS may be employed Withoutimßlbefialïîïämiïto “öf‘ficatalystoan'cl’ tneeavera‘geatimerof:lcontactïwas the quality of the hydrocarbon product. iadjustedríátzn35fiminutes. reaotionßptemper *Pressures' are Lac‘liosen‘in laccordance*with the :iatureß-‘wasì’held‘iat.x100-106°:.F.rä.thro11ghout the "'reactionweqnirements asL determined byfthef’com- @reaction ¿The ‘.-rfmalsstabilizedralkylatef;hadden position" óf -"the ìfeed " stoèk,` *the reaction- itemper- ’17 5 overall I l(boiling range rofeßo :_toë1340°;\'€E‘_qfandf~fwas 2,404,897 ' 7 substantially completely saturated. A di-iso propyl concentrate of 92.5 ASTM octane number Feedcomposition: Isobutane____per cent by'weight.~ , .. „' -made up 50 per cent of the total alkylate. Example II .f V84.15 vEthylene ___________ __`_____do_____ 15.85 Mol ratio,` isobutane/ethylene__-__ 2.56:1 Hydrocarbon/catalyst, volume ratio in The preparation of dl-isopropyl was carried out by the continuous alkylation of isobutane with ethylene in the presence of a catalyst pre - reactor _________________________ __ 2.5: 1 Contact. time _____________ __minutes..V 30 Temperature range ____________ __° F-- 120-130 . pared by saturating 85 per cent phosphoric acid Pressure ____________________ __p. s. i-- l ‘225 with boron iiuoride. The catalyst contained v53 10 The stabilized alkylate showed an overall boil per cent by weight of boron fluoride which cor responds to a mol for mol reaction between the boron fluoride and phosphoric acid and water, ing range of 8O to 350° F. Octane-number rat ings by the ASTM method with 0.0 and 1.0 cc. of tetraethyl lead were 90.0 vand 100.0, respec respectively. Substantially complete conversion of the ethylene was realized under the following 15 lreaction conditions: Hydrocarbon feed: ' Isobutane____per cent Iby weight“A 87.7 Ethylene ________________ __do_..-_ 12.3 Mol ratio, isobutane/ethylene____~ 344:1 zone ____________________ _s 2.5:1 ' .Y , urating 85 per cent commercial phosphoric acid , ` 205 with boron iiuoride. The continuous operation described in the previous example was followed 25 in this instance. The di-isopropy1 concentrate distillingjbetween 135-139° F. comprised 53 volume per cent of the total alkylate. ` The catalyst for this run was prepared by sat Contact time _____________ __minutes__ 40 Temperature range _____________ __° F__ 120-125 Pressure ___________________ __p. s. i." - The di-isopropyl concentrate dlstilling between 135-139° F. amounted to 50 volume per cent of the total alkylate. The octane rating of the'clear concentrate wasv 92.5 by the ASTM'nn'ethod."> Example V Hydrocarbon/catalyst, volume ratio inv reaction tively. Feed composition: The refractive index of this fraction (ND20, 1.3746) and the ASTM octane number (93.1) indicate a di-isopropyl content 30 Vof more than 95 per cent. l Example III The operating conditions were as follows: 1" _ y Isobutane_____per cent-by weight“ 92.5 Ethylene ______________ _`_-_do____ Mol ratio, isobutane/ethylene__’_..__ 7.5 , 6.0:1 Hydrocarbon/catalyst, volume ratio in l reactor „___1 _____________________ __ lThe catalyst 'described in Example II was em ployed in this operation. The general alkyla tion procedure involved the liquid-phase intro 2.5:1 Contact time ______________ __minutesl25 'I‘emperature range ____________ _Ã__V°.F__ 115-120 Pressure ____________________ __p. s. i__ ` ` 200 action was carried out as a semi-continuous An isoheXane fraction boiling between 13S-139° E'. amounted to 75 percent by volume ofthe total alkylate. The ASTM octane rating of the-di process »"With mechanical agitation being em isopropyl concentrate was found to be 92.7. ployed in contacting the hydrocarbon feedV and While the foregoing disclosure and exemplary operations have served to describe Vthe invention and speciñc applications thereof, it will be obvi duction of the isobutane-ethylene feed int'o a metal reactor containing the catalyst. The re catalyst. The eiiiuent from »the reactor was re cycledV to the reactor along with make-up ' ethylene. Reaction conditions were maintained A Within the following limits: l , ous that many modiiications are possiblewithin 4.7 : 1 the scope of the broad disclosure. Thus, While alkylation of isobutane has been emphasizedwith' suitable process modifications, the alkylation of isopentane may be similarly accomplished in the presence of the catalyst compositions described. In large scale commercial operations the ethylene feed to the process is preferably of relatively high Contact time ____________ _.nminutes“ 34 Temperature range _____________ __° F.- 110-120 Pressure ___________________ __p. s. i-200 inert material. However, a dilute ethylene stream may be utilized, with the inert impurities (usually Initial hydrocarbon feed: Isobutane____per cent by Weight__ ' Ethylene ` ` do Mol ratio, isobutane/ethylene_____ 89.0 11.0 3.91:1 Hydrocarbon/catalyst, volume ratio Yin reactor __` _______ __'_' _________ __'-__„ ' A completely saturated total alkylate was pro duced having a gravity of 76.6° API. A di purity to avoid the handling and separationkof ' ethane and/or propane) being separated and re turned, if desired, to the facilities producing the ethylene for further conversion. The isobutane isopropyl concentrate distilling between 134 will generally be obtained from such associated 140" F. and constituting 5_3 volume per cent of operations as segregation from reiinery or natural the total alkylate was recovered by fractionation 60 gasoline C4 fractions, normal butane isomeriza from a still of 20 to 25 theoretical plates. The octane rating of the concentrate was found to be 92.9 ASTM.` n ` Example IV . The catalyst for this run was prepared by vsaturating 50 per cent phosphoric acid with boron fluoride. The absorbed boron fluoride amounted to about 2.2 parts by Weight for each part of acid. ' The hydrocarbon feed was introduced con tinuously into the reactor containing the catalyst in a once through operation. Substantially complete conversion of ethylene was vrealized. under the following operatingconditions: tion processes, and the like. The amount-of normal butane in Ithe isobutane feed to thel proc ess may vary appreciably, and provisions Aare usually madeA to maintain suitablylow concen ` tration thereof, even with indicated isobutane re cycle. The same considerations apply to vother isoparaiiin reactants. These and other modiñca tions and adaptations 4of lthe present process will be obvious to one skilled in the art and suitable I conditions for any particular case may be readily determined by trial. I claim: - 1. A process for the alkylation of a low-boiling isoparaflin with ethylene, which comprises react ing such an isoparaffin with ethylene in an al 2,404,897 i 9 kylation zone under alkylation conditions in the presence of an alkylation catalyst comprising an addition compound resulting from the com bination of an acid of phosphorus with boron trifluoride, separating effluents of said alkylation into a catalyst phase and a hydrocarbon phase, 10 tions with a liquid catalyst comprising essentially an addition compound resulting from saturating with boron trifluoride an acid of phosphorus, in timately admixing hydrocarbons eiiluent from said alkylation zone With an acid of phosphorus to remove minor` quantities of boron trifluoride associated therewith, separating the resulting ac contacting said hydrocarbon phase with a liquid id of phosphorus-containing mixture from said acid of phosphorus to remove nonhydrocarbon hydrocarbons and adding to said mixture addi >impurities including boron triiluoride, removing tional quantities of boron trifluoride to effect said liquid acid of phosphorus from said hydro 10 substantially complete saturation thereof, and carbon phase and admixing same With at least a passing the resulting material to said alkylation portion of said catalyst phase, adding boron tri zone as catalyst. i iiuoride to the resulting mixture, passing the re 4. In a process for reacting a low-boiling iso sultant catalytic material to said alkylation zone, parañin hydrocarbon with a low-boiling olefin and subsequently separating from the resulting 15 hydrocarbon by contacting in an alkylation zone puriñed hydrocarbon phase paraffin hydrocar a mixture comprising such hydrocarbons, and bons produced in said alkylation. containing a molar excess of said isoparaiñn, un 2. A process for reacting isobutane with ethyl der alkylation conditions With a liquid catalyst ene, which comprises contacting in an alkylation comprising essentially an addition compound re zone a mixture comprising said hydrocarbons, 2.0 sulting from saturating orthophosphoric acid with and containing a molar excess of isobutane, under boron trifluoride, the improvement which com alkylation conditions with a liquid catalyst com prises intimately admixing hydrocarbons eiiiuent prising essentially an addition compound result from said alkylation zone with a liquid ortho ing from saturating with boron trifluoride aque phosphoric acid to remove minor quantities of 25 ous orthophosphorio acid containing about 85 boron triñuoride associated therewith, separating per cent by Weight of orthophosphoric acid, inti the resulting mixture of liquid orthophosphoric mately admixing hydrocarbons effluent from said acid and removed boron trifluoride from said hy alkylation zone with aqueous orthophosphoric drocarbons and adding to said mixture addi acid to remove minor quantities of boron triflu tional quantities of boron trifluoride to effect sub oride associated therewith, separating the result 30 stantially complete saturation thereof, and pass ing orthophosphoric acid-containing mixture effect substantially complete saturation thereof, ing the resulting material to said alkylation zone asY at least a portion of the catalyst employed therein. 5. The process of claim 3 in which said low and passing the resulting material to said alkyla- - boiling isoparafûn is isobutane, said low-boiling tion zone as catalyst. olefin is ethylene, and said liquid catalyst com prises essentíally an addition compound result ing from saturating with boron trifluoride aque ous orthophosphoric acid containing about 85 from hydrocarbons so treated, adding to said mix ture additional quantities of boron trifluoride to 3. A process for reacting a low-boiling isopar añîn hydrocarbon with a 'low-boiling oleñn hy drocarbon, which comprises contacting in an a1 kylation Zone a mixture comprising such hydro carbons, and containing a molar excess of said low-boiling isoparaflin, under alkylation condi 40 per cent by weight of orthophosphoric acid. WILLIAM NELSON AXE.