Патент USA US2408296код для вставки
sept. 24, 1946. s. c. cARNEY „ _2,408,294 ' CATALYTIC CONVERSION OF HYDROCARBONS Filed Nov. 13,"194'5 CONDENSEIR ._Mo N _ . RN O T _m Y / UL |_ _ _. __l 4. _5 6 E _ _\ 1 ||\ .\ \ __ 4_ SV4_ TWRl' RD..Plv7ME_._ OOABLOACl *E i î f Il/Ac2 RBDLM_A!" «_O«NUÈ9z2o.F5_É3L? \ _ERN DN_ mw _œ „un a_ 5w DL2T u _r M /_N 4G4K' _A __6 B TA 6L3R_ Um| Í| _ _ GI . _ _ ... <_ 6\ \ _ mœlvE moÈz bÉL J«_OÈ_,_ISED È _4 N N U_N63LH o\ 4\_ F mmwmmom? „__ _ __ __ __ _ + mm /m ß _«EJOÜ , ._nDREON ß.W UHl./ _NY |1_ E _ t.2 _ _ms wm _+ Am m _4L L x ? M Rf mo 9A‘l N * __R 5 _ Twm.R_momÈzCouÉÈ5.zoFäE NORE0/ O_ mœ_m _H„5l _5m _ m __„C 4 _5 _ __ TC _WM _ _ 2_ `ß / _ ____ 7, _ _ ___ï _ _2 _ c/__ A a _m _ _ _ 4/ 4./ w ANH MRD5E .l <>/„ o m5, _ _lvPo_ P_F |_ TVC. NO_E L _ _ _ _ Patented Sept. 21.4, 1946 Y' 2,408,294 UNITEDfsTATEs ' PATENT OFFICE -CATALYTIC CONVERSION 0F ZHYDROCARBONS . Samuel C. Carney, Bartlesville, Okla., assigner to Phillips Petroleum C ompany, a corporation of l Delaware - Application November 13, 1943, Serial No. 510,179 9 Claims. (Cl. E60-683.5) , l 2 . This invention relates to the conversion of hy drocarbonsinthe presence of a metal halide'cat~ .Y Aluminum chloride reacts with certain hydrocar bons, which may be present in the feed stream alyst. This invention .has particular application vor formedV in the reactor, forming an undesirable liquid `sludge of low catalytic activity. The sludge tothe isomerizationof normal parañins >to iso. paraiiins. The invention relates, _in its ,preferred modification, to the Yisomerization of normal'bu tane to isobutane in the presence oían aluminum tends to form a coating over the solid aluminum chloride preventing contact with the hydrocar-v bons. Sludge formationv represents'a loss of halide catalyst. „ Y f . , aluminum chloride catalyst. Replenishing the aluminum chloride lost by sludge formation. is Silit> the’ presenttime, conversion of straight chain v.paraffins to branchedî chain paraliins of l0, costly andthe sludge itselfis a nuisance in that` it creates a disposal problem. the. same4 number ofcarbon atoms per> molecule ` is .assuming increasing importance iin. petroleum "The idealV solid `catalyst is onejwhich Will’re-v refining operations. The isomerization yof the normal paraflins to .isoparaflinsfA is carried out ,commerciallyuwith varying` :degrees of success. lmain in solid form-under the conditions at which Y 15 Aluminum halides, ‘particularly’ aluminum chlo the y.catalyzed reaction takes place so that feed ma teria] may >be passed> in either liquid or> vapor phase Lover an extended surface of vthe catalyst. ride, are among the mostV promising catalysts- for these reactions. In carryingout isomerization of paraflins in the presence' of aluminum vchloride 'lî‘lfleldeall catalyst should be selective in itsac tion, promoting only the desired reaction, and should not react with eitherthe' feed stream or the parafñns are> contactedinl liquid or` vapor 20 the reaction products. 'From a consideration of phase vwith aluminumv chloride> inthe presence thefphysiclal, chemical,> andcatalytic yproperties of hydrogen chloride as a promoter. oflaluminum chloride,v itis evident that. it is far yfrom ideal as a lsolid -catalyst in spite of its vhigh General practice is to use the aluminum chloride insolid form, usually _admixed with »or Adeposited* on a suitable carrier material.Y „Carrier materials may catalytic activity. ' As` mightY be expected, many attempts .have been `.made to devise ay mechanical system for be coated with aluminum chloride by mechani cal mixing, by fusion of. the aluminum chloride carrying out the isomerization processwith alu with the carrier, by ¿impregnating the: carrier un minum chloride whichV would take into consider ation the undesirable physical and chemical der pressure with. molten aluminum chloride, and by sublimation oftaluminum chloride‘onto» the properties of this catalyst. l Alternatively, the .aluminum vchloride [Generally speaking, catalytic operations may may ber-used in finely divided 'formrsuspended be'cla‘s'siñed inthe following groups with respect inA an inert liquid; in liquid phase, particularly to the'phaserelationship of catalyst and react carrier. in vtheform of the double salt o_f- aluminum chlo ride with other metal chlorides; orein -the vapor 35 phase.-y ,_ . f ` , ants. ,- . . . ~ - v ..1-.y Catalyst and> feed in a single liquid phase. Vv2. Catalyst and feed both in vapor phase. I3. ACatalyst in solid. phase, feed in liquid or va Although aluminum chloride is a well known catalyst for a widevariety of reactions other than por phase.- f ‘ . 4. Catalyst in liquid'phaSe, either as such or in ing catalyst'certain problems of operation re-` 40. solution; Yfeed in vapor phase or in a second liquid isomerization, and has long been used as a crack- ' sulting from Vthe physical and chemical proper phase ï .. , ' 1 v5. Catalyst in vapor phase, feed in liquid phase. ties'of aluminum chloride have never been` Vsatis- . factorily, solved.> Aluminum vchloride hasgslight, VIn groups l and 2 the catalyst and >reactants but definite, solubility in hydrocarbons., It also possesses VAsubstantial -volatility at the tempera~ .tures required'fcr hydrocarbon conversion. Due arev inV the. mostv intimateV contact. Operations falling Within either groups land 2 >present desirable operating conditions vbecause of the nature of the „contact between the Acatalyst and v45 to the solubility in hydrocarbons'some aluminum `_ chloride is carried out of -the reactor 'inY liquid ‘the reactants; - Processes of the typey classed in eilluents. grouppl depend for operation upon complete» mis The volatility orv vapor. pressure of the reaction zone.. Solid aluminum'chloride cibilìty ofcatalyst and reactants. Since vapors are fully miscible, operation of a process inv ac cordance with _group 2 may generally ybe more tends to soften .and run together thereby reduc-l readily practiced. aluminum chloride; at` conversion Atemperatures results in contaminationcf vaporouseffluents.> of ing thelarea of_»..contact surface available and clogging -passages ¿betxveenîthe catalyst supports.' 50 . l ÈYIfhe process of the present inventionis prefer 55 2lb1y«çarried out in Voperation with catalyst and 2,408,294 3 sorber C are parts o'fthe same column as illus trated and described herein. It will be evident to those skilled in the art that these Zones may bon vapors and hydrogen chloride as promoter. The reaction then takes place in vapor phase. The aluminum chloride vapor is separated from the hydrocarbon >vapor by absorption with .anti mony trichloride. Aluminum chloride vapors are be separated orotherwise arranged While still maintaining the functions of these elements as subsequently regenerated by heating the aluminum chloride-antimony trichloride mixture which effects vaporization of aluminum chloride therefrom. The antimony trichloride, in turn,A .is re used for absorption of aluminum chloride va pors. ’The mutual solubility of aluminum chlo ride and antimony trichloride is known'. It is also -. described herein. Each of sections A, B, and C isof suitable size to eiîect the desired operation, 10 section B being generally larger than sections A or C to provide the necessary residence time re u quired to allow the reaction to take place to the ,l desired extent. - ' Hydrocarbon `feed, normal butane for isomeri 15 zation to isobutane', enters through line 2. The major portion of the feed passes to heater 3 known that antimony trichloride acts as appro moter for aluminum chloride in iscmerlzation of parañins. The present invention utilizes anti--` » mony trichloride in hydrocarbon conversion re actions in a new and useful manner. 4 drocarbon vapors. In the preferred modiñcation of this invention the still A, reactor B, and ab hydrocarbons in the vapor phase. When oper ated in this manner the aluminum chloride cat alyst is Vaporized and adrnixed with hydrocar wherein the'nor'mal butane is heated to the op erating temperature, and from which the vapors may be passed through valve 4 into the reaction 20 sectìonB or through valve 5 _to the distributor 6 . in the lower part of the still A. The normal bu. tane thus introduced contacts vapors of alumi num chloride and hydrogen chloride in vapor ants in vapor phase are: phase in the reactor where isomerization of nor 1. Solid aluminum chloride with its attendant 25 mal butane to isobutane takes place. disadvantages is not present in the reactor. The temperature in the reaction zone is above 2. Perfect contact of catalyst and hydrocarbon the vaporization temperatureof aluminum chlo While both are in Vapor phase is attained in the ride and below the temperature at which u_nde sirable reactions take place. Aluminum chloride 3. Coating of catalyst with sludge is elimi sublimes at a temperature of about 178° C'. and has a boiling point of about 183° C. at atmos ` 4. The process may be operated continuously pheric pressure; At 21/2 atmospheres pressure without necessity of interruptions to replace cat The advantages of operating in accordance with the present invention with catalyst and react reactor. nated. . . . ' ~ the boiling point of aluminum chloride is about alyst. y y Y l „ 190° C. Accordingly, the temperature in the re An object of this invention is to provide „an im action'chamber maybe within about 190° C. _to about 250° C. Preferably the temperature with proved process for the conversion of hydrocar bons in the presence of a metal halide catalyst. . in the reactor is coniined within the limits of about` 190° C. to about 220° C. The isomeriza tion of normal .butane to isobutane is exothermic, mal paraffins to isoparaflins. ' Still another object of this invention is to pro 40 hence there is a tendency for the temperature to increase from the bottom to the top of section B. vide such a process wherein parafñns are isomer The temperature in section B may be controlled ized in the presence of a metallic halide catalyst by injection of normal butane at one or more wherein the catalyst and reactants are in Vapor points along the length of the reaction chamber. phase. The temperature at the top of the reaction cham A further object of this invention is to provide ber B is limited to a value below about 200° C. an improved process for the vapor phase isom by the addition of fresh normal butane, prefer erization of normal butane to isobutane inthe I Another object of this invention is to provide an improved process for the isomerization of nor presence of vaporous aluminum chloride as a cat alyst. ' A still further object of this invention is to pro vide a process for the separation of aluminum chloride vapors from hydrocarbon vapors byfab sorption with antimony trichloride. ‘ Further objects and advantages of this inven tion will be evident from the following detailed description of specific applications of the inven tion and the accompanying drawing illustrating diagrammatically the described specific embodi ments. f ' y ' Figure 1 illustrates diagrammatically appa ratus suitable for carrying out paraflin isomeriza so ably in liquid form to take advantage of the heat of vaporization. For this purpose, a part of the normal butane from line `l is passed through line 1 to a distributor 8 _in the reaction chamber B. Vapors from the reaction chamber, comprising hydrocarbons, hydrogen chloride, ' aluminum chloride, and antimony trichloride vapors, pass through the chimney 9 into the absorber C. The absorberC is provided with vapor-liquid contact means, as,` for example, packing or bubble plates. In the absorber the> vapors from the reaction chamber are brought into contact with liquid an 60 timony trichloride. The temperature in the ab sorption section is preferably within the range of 180° C. to about 200° C. The antimony trichlo tion by the process of this invention. ` ' ride absorbs aluminum chloride vapors from the Figure 2 illustrates diagrammatically appa hydrocarbon stream. The mixture of aluminum ratus suitable for a more general application` of the process of the present invention to hydrocar 65 chloride and antimony trichloride hows from the absorber C through the downspout I0 to the va bon conversion. porizer or still A. Still A preferably is provided ' With reference to Fig. 1 of the drawing, the with plates or packing providing vapor-liquid numeral l designates a column of suitable size Contact means similar ot that of the absorber. divided into three sections, A, B, and C. section Heat is supplied to the still by suitable heating A constitutes a still in which aluminum chloride means, e. g., steam coil. In the still the alumi is vaporized.l Section B is the reaction chamber in which reaction of the hydrocarbon takes place num ychloride is _liberated from the antimony tri chloride and passes up into the reactor B. The in vapor phase in the presence of aluminum chlo hydrocarbon vapor'supplied tothe still from the ride vapors. Section C is an absorber in> which aluminum chloride vapors are separated frornhy 75 distributor 6 aids in the vaporization of the alu 2,408,294 6 . min'um 'chlorideby its 'stripping action.v audits eiïecton .thel partial’npressures in the still., The 7 num` `chloride ,; Sludge which may be; formed in temperature in the stillV is maintained within the Vaporized aluminum chloride'enters theN reactor through line 45 as. will be evident- from the fol range ofxabout 180° C..toV about'220° C'. t ‘ Liquid .antimony trichloride is.v drawn from the stilland passed by‘pump l2 to the cooler I3;V The coolerylâ may conveniently be cooled by boi-ling water'to` obtain a temperature approaching 100° C. -In any case the antimony trichloride isnot cooled below about 80° C. since-it solidiiies at '1 31.4° C. The cooled antimony _trichloride isi ythen passed through line I4 to the upper part of the absorber C> for further absorption of` aluminum chloride vapors, thereby'completing its cycle. A part of the stream from theabsorber Cfmay be passed via line l5 to a-catalyst make-,up chamber l5. Inchamber I6 fresh aluminum .chloride is the'reactor, :maybe withdrawnithrough line 44. lowing description of_ operation. The hydrocar bons leave the reactor in vapor phase through line 4S at a temperature above about75° C. and are cooled, if necessary, to a temperature belowabout 200°fC. before entering the absorber 41. The temperature inf reactorliß` may be any' tempera ture necessary for carrying out the reaction. The isomerization of normal parañins to isoparaiiîns may be conductedat temperatures in the range . of Aabout 50° C. to about 250° C.; cracking', gener ally at temperatures above about 250° C. It willbe recognized by thosek skilled in the art» thatV the composition of the feed and other operating» con ditions` aiîect the reaction and govern the tem' antimonyl trichloride from the absorber to the perature at which a given reaction'is> best' carried still A through line I1. ’ 20 out. The temperature in the reactor is immate The hydrocarbonvapors, lfreed from alumi rial to the operation of this modification of the num chloride vapors, leave the column by line 20 present invention, it being essential only that and passito the condenser 2| ; g Condensate is col the temperature of the vapors entering the ab lected` inA the accumulator.k 22 and fed via line` 24 sorber d1 be within. the range of about '15° C. to the fractionator 25. The fractionator 25 is to about 200° C. provided with suitable refluxing and reboiling In the absorber 41, the hydrocarbon vapors added, as needed, and-_passes in solution in the Hydrogen chloride is containing vaporous aluminum chloride are con separated from' the hydrocarbons and returned to ¿column I via line 2,0. Additional hydrogen chloride may be supplied as needed »through line 21. Fromvfractionator 25, thev hydrocarbons are means as is customary. tacted with liquid antimony trichloride which ef passed through line-_2,8 to. the fractionator 29 in fects solution ofthe aluminum chloride vapors. Fresh antimony trichloride may be added tothe absorber- and saturated antimony trichloride, re „ moved from theY absorberasî required, e. g.,„«in Which'the-isobutane is lseparated from unreacted t the V,manner described in‘connection'with Fig. 1 by _ j normalbutane. ¿The isobutane passes overhead means of, lines 63 and 64, respectively. Thefab throughline 30; normal butane is returned 35 sorbed. aluminum’chloride is subsequently vapor recycle for throughfline 3f! to the‘heater 3- as ize'd from the. antimony> trichloride Iin the vapor conversion ¿to isobutane. ` ~ The foregoing detailed description is speciñc to Y the isomerization of normal-butane _to isobutane izer 48 and returned to the reactor 40. through line 45. The vaporizer 48 is provided with heat ing means 49 and means 50 for admitting strip , in the presence of aluminum chloride as catalyst 40 ping vapor .thereto to >'effect Vaporization of alumi using hydrogen chloride as promoter for the reac tion. Itis to be understood that inthe process of the present invention, normal parafûns other than butane may be employed as feed tothe isomerization reaction. The aluminum chloride is promoted by a hydrogen halide, generally hy drogen chloride is employed because of its avail ability. It is well knownrthat other metal halides numchloride. It will be evident to rone skilled inthe art that the.. absorber and vaporizer may be so constructed asto be interchangeable, each serving alternately asfabsorber and vaporizer. Hydrocarbon vapors freed of aluminum chlo rideare passed from the absorber 41 to the con denser 52. Condensate from the condenser col lects in accumulator 54 from which it is passed catalyze the isomeriaationreaction and that these tothe fractionator' 55. `The promoter is'separated catalysts may be promoted by hydrogen halides. 50 from thehydrocarbons and returned to the reac Aluminum bromide is known to be a goodrisomer tor through -line 51; additional promoter may ization catalyst which may befpromotedby hydro be added as requiredthrough-line 58. The hydro gen bromide. It is also known to use mixtures of _aluminum chloride and aluminum bromide as carbons are passed fromthe fractionator. 56 to a second fractionator 60 for separation of product catalysts for this reaction. l 55 from unreactedhydrocarbons. The desired prod `-Figure 2 of the drawing illustrates inra more uct leaves the fractionator by line 6|; unreacted generalwa-y the application of the ¿present inven hydrocarbons kare returned to the reactor 40 tion to hydrocarbon conversion processes in which through line 62. . f an aluminum chloride catalyst is used. Cracking, Antimony trichloride is liquid at atmospheric isomerization, orother-reaction promoted by alu 60 pressure at temperatures within the range of minum chloride may be carried out in the appa about-'14° C. to about 220° C, This liquid is readily ratus illustrated. >Reaction takes place inthe transferred from point to- point in the system. reactor 4u in the presence of aluminum chloride - While; aluminum chloride is solid atV tempera as catalyst and~hydrogen»_ chloride as promoter. tures below aboutg180°` C; it should be noted that The ,aluminum chlorideis preferably present in 65 it has va definite vapor pressure at temperatures the reactor in vapor phase; it Will be evident, however, thatV aluminum chloride maybe present ` below'its melting point. The vapor pressuresV of in the reactor Ain liquid or .vaporr phaseL The aluminum chloridel atv various temperatures are approximately as follows :` hydrocarbon feed enters the reactor through line42. A suitable coolant, preferably hydrocarbons, 70 « , t may Vbe added to the reactor through line 43 as Aadmitted through line 42 or line_43 if desired. 100° 120° 140° 160° Liquid hydrocarbons, togetherwith `any- a1umi‘-` 170°."C,... desired. The aluminum chloride is charged to Y( thereactor in any convenient manner; it may be 'Mm. Hg C __________________________________ _„ 1 C-, ________________________________ _, 9 C; _________________________________ __ 44 C ___________________________________ _. 234 _. 513 2,408, 294 8 7 Witli‘ molten antimony trichloridein an absorbing In view of the fact that‘hydrocarbon vapors are present in large quantities in the reactor, it zone and thereby .dissolving aluminum chloride from said mixture -in said >molten antimony trl chloride while allowing the resulting vaporous will be readily appreciated that large quantities of aluminum chloride vapors appear in the hydro carbon vapors even When using solid aluminum mixture of unconverted normal parañîn, isopar chloride at temperatures below the vaporization temperature. The present invention has Wide ap añ'in and hydrogen halide to pass through undis solved, passing the resulting solution of aluminum chloride in antimony trichloride to a stripping plication in the removal of aluminum chloride zone and there stripping the dissolved aluminum vapors from hydrocarbon vapors in the eiliuents of hydrocarbon conversion processes in which alu 10 chloride in> vaporous form therefrom, and pass ing the resulting vaporous aluminum chloride into minum chloride is used as catalyst. said reaction zone. f I claim: 6.' A process for the vapor-phase isomerization 1. A process for the conversion of hydrocarbons of normal parañins to isoparafñns in the presence in . a reaction catalyzed by aluminum chloride which comprises contacting the` hydrocarbon With 15 of aluminum chloride which comprises contacting vapors of a normal paraiiin with aluminum chlo aluminum chloride in a reaction zone under con ride vapors in the presence of hydrogen chloride ditions such that the desired reaction is effected, at a temperature within the range of about 190° C. passing vaporous eiiluent from the reaction zone to about 250° C. in a reaction zone in the absence containing hydrocarbon vapors and aluminum chloride vapors into contact with liquid antimony 20 of liquid phase; passing vaporous eilluent of said reaction zone containing vapors of aluminum trichloride effecting separation of aluminum chlon chloride, hydrogen chloride, normal parañin and ride vapors from the hydrocarbon vapors by solu isoparaflin into intimate contact with molten an tion in liquid antimony trichloride, subsequently timony trichloride at a temperature Within the liberating aluminum chloride vapors from liquid range of about 180° C. to about 200° C. in an ab 25 antimony trichloride, and returning the aluminum sorption zone thereby dissolving aluminum chlo chloride to the reaction zone as catalyst. ride from said vapors while allowing the hydro 2. In a process for conversion of hydrocarbons gen chloride, normal paraffin and isoparafûn va in a reaction catalyzed by aluminum chloride, the pors to pass through undissolved’; passing the re > improvementY which comprises contacting va sulting solution of aluminum chloride in anti porous` eiliuents of the reaction containing alumi 30 mony trichloride to a distillation zone and liber num chloride vapors in admixture with hydro ating the aluminum chloride from the antimony carbon vapors With liquid antimony trichloride trichloride in said zone at a temperature Within eiîecting separation of aluminum chloride vapors the range of about 180° C. to about 220° C. in the from the hydrocarbon vapors by solution in liquid 35 presence of hydrocarbon vapors as stripping me antimony trichloride, and subsequently liberating dium; and passing aluminumv chloride vapors aluminum chloride vapors from liquid antimony trichloride. from the distillation zone to said reaction zone. 7. The process of claim 6 in which said normal . ’ 3. In a process for the conversion of hydrocar paraffin is normal butane and said isoparafl‘ln is bons in a reaction catalyzed by aluminum chlo 40 isobutane. Y ride, the improvement which consists in contact 8. A process for isomerization of normal par ing vaporous eñ‘luents of the reaction containing ailins to isoparafûns which comprises contacting aluminum chloride vapors and hydrocarbon va said normal' paraiñn with aluminum chloride in pors With liquid antimony trichloride effecting a reaction zone in the presence of hydrogen halide separation of aluminum chloride vapors from the and at a temperature within the range of'about hydrocarbon vapors by solution in liquid antimony 50° C. to about 250° C. effecting isomerization of trichloride. normal paraffin to isoparafûn, passing vaporous 4. A process for the conversion of hydrocarbons eflluent of said reaction zone to an absorption in a reaction catalyzed by aluminum chloride zone into intimate contact with liquid antimony which comprises contacting the hydrocarbons 50 trichloride at a temperature Within the range of with aluminum chloride in a reaction zone, pass ing vaporous eiiluent from the reaction zone con about ’75° C. to about 200° C. effecting selective solution of aluminum chloride vapors contained therein, passing the solution of aluminum chlo ride in antimony trichloride to a distillation zone and vaporizing aluminum chloride from antimony taining aluminum chloride vapors to an absorp tion zone into contact with liquid antimony tri chloride at a temperature in the range of about 75° C. to about 200° C. effecting removal of alu trichloride in said zone at a temperature in the minum chloride from said hydrocarbon vapors by solution in liquid antimony trichloride, passing antimony trichloride containing aluminum chlo ridein solution therein from the absorption zone to a distillation zone, liberating aluminum chlo ride from antimony trichloride in the distillation zone by heating to a temperature within the range range of about 180° C. to about 220° C.; and pass ing aluminum chloride thus liberated in the dis tillation zone to the reaction zone. 60 9. A process for the vapor-phase isomerization of normal butane to isobutane which comprises passing vaporous-normal butane into a body of to the corresponding isoparafñn Which comprises liquid antimony trichloride having aluminum chloride dissolved therein and maintained at a temperature adequate to vaporize said aluminum chloride therefrom, passing resulting vapors of normal butane and aluminum chloride upwardly intimately contacting the normal paraffin in va por phase with volatilized aluminum chloride posed above said body of liquid and maintained at of ‘about 180° C. to about 220° CL, and passing the liberated aluminum chloride vapors from the dis tillation zone to the reaction zone. 5. The process of isomerizing a normal paraffin into and through a separate reaction zone dis as a catalyst in the presence of an anhydrous 70 isomerization conditions of temperature and pres sure and substantiallyfree from liquid phase, said reaction zone being of sufñcient size to eiîect sub stantial vapor-phase isomerization therein, pass of time such as to effect isomerization to the iso ing resulting vapors of normal butane, isobutane paraiììn, removing the resulting mixture in vapor state from said reaction zone and scrubbing it 75 and aluminum chloride upwardly into and through hydrogen halide promoter in a reaction zonesub-V stantially free from ‘liquid phase and for a period 2,408,294 ~ a separate scrubbing zone disposed above said re action zone, contacting the last-mentioned vapors in said scrubbing zone with liquid antimony tri ohloride to dissolve substantially all of the A1013 from said vapors, recovering from said scrubbing zone vapors comprising isobutane substantially free from aluminum chloride, ñowing resulting solution of aluminum chloride in liquid antimony 10 _ „ ` trichloride by gravity to said body of liquid anti mony trichloride through a- path separate from Y said reaction> zone, and passing liquid antimony trichloride from said body of liquid antimony trichloride to said scrubbing zone for use therein , to dissolve aluminum chloride from normal bu tane and isobutane vapors. ' SAMUEL C. CARNEY.