2,412,675 Patented Dec. 17, 1946 UNITED STATES PATENT OFFICE 2,412,67 5 IS ORIERIZATION 0F SATURATED HYDROCARBONS Joseph D. Danforth, Riverside, Ill., assignor to Universal Oil Products Company, Chicago, Ill., a corporation of Delaware Application February 11, 1943, Serial No. 475,515 8 Claims. (C1. 26o-683.5) l This application is a continuation-in-part of my co-pending application Serial No. 370,323, ñled December 16, 1940. The present invention relates to the catalytic 2 in substantially liquid phase is passed through a contact zone containing a metallic halide of the isomerization of saturated hydrocarbons such as Friedel-Crafts type under conditions of tempera ture and pressure such that an amount of cat alyst adequate to maintain the desired catalyst butane, pentane, hexane, naphthenes such as cyclohexane or hydrocarbon fractions boiling dissolved in the liquid hydrocarbon. the course of reaction due to depletion or con packing materials. concentration in a subsequent reaction zone is The cat alyst containing solution from said contact zone Within the gasoline range containing substantial is reacted in the presence of a hydrogen halide quantities of these hydrocarbons. More specifi cally it deals with an improved isomerization 10 in a reaction zone maintained under conditions of temperature and pressure sufficient to convert process wherein the catalyst in the reaction zone a substantial portion of the saturated hydro is constantly being renewed by the introduction carbons to isomers thereof. The desired concen of fresh catalyst to said zone in solution in at tration is maintained in said reaction Zone by least a portion of the hydrocarbon charge. The previously proposed processes for the 15 continuously supplying thereto small increments of fresh catalyst from a bulk supply in the first isomerization of saturated hydrocarbons with contact zone in solution in at least a portion of catalysts of the Friedel-Crafts >type generally one the saturated hydrocarbon charge. Y or more halides of aluminum, zirconium, zinc, To obtain satisfactory results in the present iron and the like, in the presence of‘hydrogen halides consisted of passing the hydrocarbons 20 invention it is essential that some means be uti lized to retain in the reaction zone at least a and hydrogen halide through a fixed bed of gran portion of the catalyst being introduced into said ular catalysts either alone or deposited on solid zone in solution in the hydrocarbon charge. Suit-A supports under conditions of temperature and able materials for this retention of the catalyst pressure such that a portion of saturated hydro may comprise granular particles or shaped bodies carbons are converted to isomers thereof. One of solid materials such as rachig rings, burl of the most serious disadvantages in these proc saddles, crushed fire brick and other Well known esses is the decrease in catalyst activity during During the initial period of the operation only tamination of the active catalytic materials pres ent. Due to the continual change in catalyst ac 30 a small portion of the catalyst entering the re action zone is removed in the reaction products tivity during the operation, it is necessary to from said zone, the remaining portion adheres vary the operating conditions to compensate for to the surfaces of the packing materials disposed losses in activity in order to maintain a suitable within the zone. As the operation continues, the conversion of the saturated hydrocarbons to isomers thereof. This variation in operating con 35 packing material will become saturated and a point will be reached Where the amount of cat ditions introduces additional diñiculties and com alyst being removed from the reaction zone either plications in the operation and results in a de in the reaction products as free catalyst or com crease in the commercial applicability of the bined with a portion 0f the hydrocarbons is sub proposed isomerization processes. In spite of the adjustment of operating conditions, the catalyst 40 stantially equivalent to the amount being intro activity decreases to an extent Where it is no longer commercially feasible to continue the op eration which necessitates discontinuing the isomerization and replenishing the catalyst in the reaction zone. Various modiñcations of operat ing procedure, such as the use of a plurality of reaction zones have been proposed but these duced into said zone in solution in the hydrocar bon charge. After the establishment of this equilibrium the catalyst concentration will be maintained substantially constant throughout 45 the remainder of the operation. This catalyst concentration will be in substantial excess of that in the incoming catalyst containing solution due primarily to the retention of a portion4 of the catalyst by the packing materials in the reac modifications, multiply to a considerable extent the operating difûculties encountered. The present invention provides an improved 50 tion zone. In one speciñc embodiment, the present in method wherein a more continuous and substan vention relates to a process for isomerizing sat tially more economical process than has been urated hydrocarbons which comprises passing a hitherto possible is obtained. stream of said saturated hydrocarbon in substan~ In accordance with the present invention at least a part of the saturated hydrocarbon charge 55 tially liquid phase through and in relative move 2,412,675 3 ment to a bulk supply of metallic halide catalyst 4 The catalyst disposed within tower I4 may of the Friedel-Crafts type in a ñrst zone under comprise aluminum chloride, zinc chloride, zir conditions such that only a portion of said cat alyst is issolved in said liquid hydrocarbon stream, commingling the catalyst containing conium chloride either alone or in admixture effluent from said ñrst zone with a hydrogen hal ide within a second ,- zone maintained under isomerizing conditions and converting a substan tial portion of said saturated hydrocarbons to isomers thereof in said second zone in the pres ence of the catalyst supplied thereto froml the. ñrst zone. I have discovered that by introducing the catalyst into the reaction zonein _solution in, at _ with one another or any other well-know Friedel Crafts type isomerizing catalyst which possesses sufficient solubility in the hydrocarbons being charged, under the particular conditionsof tern perature and pressure maintained in tower I4 to dissolve an adequate amount to maintain the 10 desired catalyst concentration in the subsequent reactor. For. a completely continuous operation, it is desirable to have a second tower similar to tower Mithrough which theA hydrocarbon stream may least a portion of the hydrocarbon .charge the 15 lne-converted while tower I4 is being reñlled with catalysts. The emuent solution in tower I4 is desired amount of catalyst may be transferred directed through line l5 containing valve I6 into . from the bulk supply to the reaction chamberat reactor VI wherein it is commingled with a hy comparatively low temperatures. If, on the drogen halide obtained as hereinafter set forth. other hand, vapors of the hydrocarbon charge~ are used as a carrying medium, higher tempera 20 The temperatures and pressures maintained in tures4 must,_be utilized-to carry an equivalent amount- ofgcatalyst.` The `use of higher tem peratures causes considerable,decomposition of the charging stock in the catalyst supply zone reactor I'I‘are dependent upon the hydrocarbon and. Catalyst being utilized in the operation. When utilizing aluminum. `chlorideas, the isom erizing catalyst this temperature will be ordi resulting ,in increased _catalyst consumption due to thevformation of hydrocarboncatalyst com plexes by the reaction of the catalyst with the narily within the approximate range of 50 to 300° F. With various other catalysts good conver sions are obtained upto temperatures of about decomposition products. 40095F. Thefpressure is dependent upon the hy Utilization _of liquid phase transfer also pro vides a simple method of regulating the rate of catalyst introduction._ This rate will be pri marilydependent upon _the _temperature in the supply zone which _will control the solubility of the catalyst in the hydrocarboncharge. With vaporphase transfer, the rate of catalyst in troduction willbe dependent not only on the drocarbonV phase desired in reactor I‘I. I have found that the isomerization reaction will pro ceed-satisfactorily in the liquid, mixed or vapor temperature but also on the pressure which con siderably increases complexityvof vthe operation. Furtherfeatures and advantages of the pres ent ¿invention will be evident from a considera tion of the follow-ingpdescription of the accom panying _diagrammatic drawing of one type of apparatus» in which the objects .of the invention may> be, accomplished. For- simplification such units as heat ex phase». In the preferred mode of operation, reactor Il is packedv with any» of `the well-known» packing materials such as rachig rings, berl saddles, crushed fire-brick, etc. This packing provides a surface -uponwhich a portion of the catalyst may deposit so that vatv all» times during the opera tion the amount of »catalyst present in` reactor I‘I 40 is> greater than that being introduced in the hy drocarbon stream from-catalyst supply tower I4. As a specific modification of the operation, a portion of> the-butane leaving pump 3 may be directedfto line 6 vcontaining lvalve -I into heat ingv coil_v8-«disposed within furnace 9 wherein it is >heated, -to the _desired temperature and trans chgnrgers;` condensers, reboilers, etc., which are not essential to the lunderstanding of the de ferred through line _dI-containingvalve 42 into scription have been eliminated.A reactor I'I.~ Thisy method of operation increases Referringto the drawing,_ a saturated hydro to Ía considerable vextent the ,flexibility of the regulationorthe temperature and catalyst con carbon,v forexample, normal butane, is intro duced through line I containing valve 2 into centration within reactor; I l. The amount of catalyst-'removed -from tower I4 is dependent pri pump 3 which discharges _through line `¿l con marily'upon the solubility of the catalyst in the taining vvalve i_5 into heating coil I0 disposed with hydrocarbon -»and the amount of hydrocarbon in furnace I I_.¿ The heat absorbed by the butane during its Ypassage through heating coil I0 is ¿3. Passed throughsaidtower perunit time. It is obvious that by varying _the proportionsvof the suiflcienttocompensate for any losses in heat two streamsv entering furnaces 9 and II, respec during the transfer Yof the heated butane streamv through line I2 containing, valve I3 and still tively, theamount of catalyst Vcarried into re actor I'I may be _varied while maintaining a con maintain ,the desired temperature in catalyst stant charge of hydrocarbons to said zone. The supply- tower I4.. The temperature within tower hydrocarbon Vstream »passing through,> furnace 9 I4 is dependent îupon* the particular isomeriza may be heatedY to a temperature substantially in tion catalyst used >andthe solubility of the cata lyst in the hydrocarbon. In the broader aspects excess of that desired in catalyst »tower I4 and can _be vutilized as a heat carrying medium to of _the invention, this temperature is within the range of about .100 to about 350° F. However, -» produce the desired ¿temperature when com narrow rangesY areapplicable to the particular isomerization catalyst utilized for example, a mingled with; the.,cata1yst` containing _stream fromtowerll! andthe added yhydrogen halide temperature range of approximately 140 to 250° F. is desirable when employing an aluminum within reactorv I‘I.~ Further ¿advantages ,are` ob tained in that this method of operating obviates chloride while with other metallic halides, such the, necessity bycontactinggthebulk-supply of catalystgwith thegentire charging stock. This is extremely important inthe event, that Vthe as zirconium chloride Vand zinc chloride, a higher temperature up to approximately 350° F.» may be used.` The pressure in towenlftwill vary with the temperaturehut.- itis essential that a liquid phase. , be. maintained. within. said, tower._ charging stock containsgimpurities which may poison orconsume the catalyst. During~ thereactiona minor amount of the hy "2,412,675 5 drocarbon reacts with the catalyst to form a com plex commonly termed sludge which is withdrawn from reactor l1 through line i8 containing valve I9; The remaining reaction products are directed through line 20 containing valve 2l into hydrogen chloride separator 22 wherein the hydrogen chlo reaction zone in an amount equivalent to about 11.7 mol per cent of the butane charge. Approxi mately 40.3 per cent by volume of isobutane was formed during the passage of the normal butane through the reaction zone. Eœample 2 ~ Y ride and light hydrocarbon gases, such as ethane and propane formed during the reaction are sep A normal pentane fraction heated to 170° F. was introduced into a catalyst pickup chamber arated from the isobutane and unconverted nor containing a bed of granular aluminum chloride. mal butane. The hydrogen chloride and a por '10 The chamber was maintained under a pressure tion of the light hydrocarbon gases are recycled of 260 pounds per square inch. Hydrogen was through line 35 containing valve 40 into reactor introduced to the pickup chamber in an amount I1. ' The original charge of hydrogen chloride and equivalent to 10 mol per cent of the hydrocarbon any additional make-up necessary during the op charge. The eiiluent liquid having an aluminum eration is introduced through line 38 containing chloride concentration of about 1.1 pounds of 4valve 39 into recycle line 35. The concentration aluminum chloride per barrel of charge was com of hydrogen chloride in reactor l1 is dependent mingled with hydrogen chloride in a packed re upon the particular conversion temperature- and action zone maintained at a temperature of 250° hydrocarbon charge, but is ordinarily Within the F. and under a pressure of 250 pounds per square approximate range of 1 to 40 mol per cent of the inch. The hydrogen chloride concentration in hydrocarbon and preferably within the approxi mate range of 5 to 25 mol per cent. ' ` I have found that the addition of hydrogen in some instances increases the eñiciency of the operation. This hydrogen may be introduced along with the hydrogen chloride through line 38 containing valve 39 into recycle line 35. The amount of hydrogen introduced will usually be less than approximately 30 mol per cent of the the reaction zone was 10 mol per cent of the pen tane charge. A conversion' of about 45.5 per cent by volume of the charge to isopentane was ob tained during the passage of the normal pentane through the packed reaction zone. Example 3 A 39 octane number acid-treated hexane frac tion was introduced into a catalyst pickup cham 30 hydrocarbon charge. Further addition of hydro ber containing a bed of granular aluminum chlo -gen may be made through line 43 containing Valve ride. The catalyst pickup chamber was main 44 into catalyst supply tower I4. To avoid a build tained at a temperature of 170° F. and under a up of light hydrocarbons, such as methane, ethane pressure of 500 pounds per square inch. The eiilu and propane in the system, a portion is period ically withdrawn through line 36 containing valve 35 ent liquid from the pickup chamber having an alu minum chloride concentration of about 1 pound 31 and the saturated gases'recovered as a prod per barrel of hexane charge was commingled with uct of the reaction after the removal of the hy about 10 mol per cent of hydrogen chloride in a drogen chloride therefrom. packed reaction tower. The octane number of The isobutane-normal butane stream is di the product was about 72.3, an improvement of rected from separator 22 through line 23 con 33.3 octane numbers over the charge. taining valve 24 into fractionator 25 wherein the I claim as my invention: isobutane is separated from the unconverted nor 1. An isomerization process which comprises mal butane. The separated isobutane is with subjecting an isomerizable saturated hydrocarbon drawn through line 23 containing valve 2l and to catalytic isomerization in a reaction zone con `recovered as a product of the reaction. Theun 45 taining a solid packing material and maintained converted normal butane is directed through line under isomerìzing conditions, maintaining in a v28 containing valve 29 into pump 30 which dis catalyst supply zone a bed of fresh Friedel-Crafts charges through line 3| containing valve 32 into metal halide catalyst not previously used in said line I2. A portion of the recycle normal butane may be directed through line 33 containing Valve 50 reaction zone, heating a liquid stream of said isomerizable saturated hydrocarbon to a tem 34 into reactor l1 along with the heated butane perature sufficient to dissolve a portion of said stream from furnace 9. ` catalyst, thereafter passing the heated stream The following examples are presented as being in substantially liquid phase through said bed in characteristic of the results obtained when op erating in accordance with the present inven 55 the supply zone and dissolving a portion of the bed in the liquid stream, introducing the result tion, although it is not intended to limit the gen ant catalyst-hydrocarbon solution to the reaction erally broad scope of the invention to the specific zone and depositing catalyst from the solution _conditions presented in the examples. onto said solid packing material to maintain in Eœample 1 the reaction zone a catalyst concentration sub 60 stantially greater than that of the solution be. A stream of normal butane heated to a tem ing introduced to the reaction zone, effecting said perature of 180° F. was introduced into the bot catalytic isomerization of the saturated hydro tom of a catalyst tower containing granular carbon in the presence of the catalyst thus re >aluminum chloride. The tower was maintained 65 tained in the reaction zone, substantially all of at ay pressure of 250 pounds per square inch to the requisite quantity of fresh metal halide cat insure the presence of a liquid phase of normal alyst for effecting said catalytic isomerization butane. The eilluent solution having an alu being supplied to the reaction zone in said solu minum _chloride concentration of 1.7 pounds per tion, removing resultant reaction products from barrel of charge was commingled with a second the reaction zone and supplying the same to a stream of heated butane and the resulting mix 70 fractionating zone without passage thereof ture having a temperature of 220° F. introduced through the catalyst supply zone, and fractionat --into a packed reaction zone. The butane stream ing the products in the fractionating zone to re Acontaining aluminum chloride dissolved therein cover the isomerized hydrocarbon therefrom. amounted to about 47 per cent of the total mix 2. A process for isomerizing an isomerizabl'e 75 ture. Hydrogen chloride was introduced into the «2,412,675 8 saturated hydrocarbon-which comprises heating .dissolving a-'portion of the bed in the liquid stream',fintroducing the resultantaluminum chlo~ a liquid stream comprising aiportionof ‘saidïhy drocarbon and then passing the 4heated stream in substantially liquid phase :through a bed of fresh Friedel-Crafts metal v'halide catalyst at a ride-hydrocarbon ksolution tothe' reaction zone 'and depositing aluminum chloride-catalyst from the solution onto said solid packing `material rto temperature su?licientto dissolve a portion of said maintain in the reaction zonean aluminum chlo bed, introducing the resultant catalyst-hydro ride concentration substantially greater lthan carbon solution to a reaction’zone containing a that of the solution being introduced 4to the re solid packing material, separately heatinga sec .action zone, effecting said catalytic isomeriza ond portion of said hydrocarbon to ya higher tem 410 »tion of' the saturated hydrocarbon in the lpres perature than the nist-mentioned portion and then introducing the same directly-¿to Ythe reac tion zone, the amount and temperature 'ofi said separately heated' second ‘portion being suiîlc'ient to maintain an isomerizing temperature in ¿the ence of the aluminum chloride catalyst Ithus re tained in the reaction zone, substantially all of the requisitequantity of fresh aluminum chlo ride catalyst for eiîecting said catalytic isomeri zation being supplied to the'reac'tion zone in -said reaction zone, depositing catalyst ïf'rom said so lution onto said solid packing material to main tain in the reaction zone a catalystconcentra solution, removing resultant reaction products fromxthe reaction zone and supplying the same to a fractionating zone Without passage thereof tion substantially greater 'than that-of «said 'solu through the catalyst supply zone, and fraction tion, effecting substantial isomerization of said 20 ating the products in lthe fractionatingezone to portions of the hydrocarbon> in `the presence of recover the isomerized hydrocarbon therefrom. the catalyst thus retained in 'the- reaction zone. substantially all of the requisite-quantity of fresh metal halide catalyst for eii‘ecting said catalytic isomerization being supplied tothe reaction zone in said solution, removing resultant reaction products from said zone‘and recovering the isom erized hydrocarbon therefrom. 3. An isomerization process »which comprises subjecting an isomerizable saturatedhydrocarbon 30 to catalytic isomerization in the presence of a hydrogen halide in a reaction zone containing 5. A process for isomerizing an isomeriz'able saturated hydrocarbon which comprises .heating a liquid stream comprising a portion of said hy drocarbon and then 'passing the heatedv stream in substantially ‘liquid phase .through .a `bed of fresh .aluminum halide at altemperature. suffi cient to dissolve afportion of said bed, 'introduc ing the resultant aluminum halide-'hydrocarbon solution and a hydrogen .halide toza reaction zone containing a solid packing material, separately heating a second portion of said hydrocarbon to a solid packing material and maintained under a higher temperature than thev first-mentioned isomerizing conditions, maintaining in a catalyst portion and -then introducing the same `.directly supply zone a bed of fresh aluminum halide cat to the reaction zone, the amount and .temperaalyst not previously used in said reaction zone, ture of said separately heated second portion be heating a liquid stream ofV said isomerirable` sat ing suñicient to maintain an visomerizing tem urated hydrocarbon to a Atemperature sufficient perature in the reaction zona-.depositing .alumi to dissolve a portion of-said aluminum halide, num halide catalyst from 4said Asolution ontoï said thereafter passing the heated stream in substan 40 solid packing material to'maintain in the re tially liquid phase through said bed in the supply action zone an aluminum halide~ concentration zone and dissolving a portion of the bed in the substantially greaterthan thatof said solution, liquid stream, introducing the resultant alumi effecting substantial isomerization of said por num halide-hydrocarbon solution to rthe reaction zone and depositing aluminum halide catalyst from the solution onto said solid packing ma reaction zone, substantially all. of v the‘requisite terial to maintain in the'reaction zone an alu quantity of fresh-aluminum halide catalyst for tions of the hydrocarbon inthe presence -of the aluminum halide-catalyst thus' retained in the minum halide concentration substantially great er than that of the solution being introduced to the reaction zone, effecting said catalytic isomeri- ~ zation of the saturated hydrocarbon in the pres ence of the aluminum halide catalyst thus re tained in the reaction zone, substantially all of the requisite quantity of fresh alurm'num halide catalyst for effecting said catalytic isomeriaa tion being supplied to the reaction zone in said solution, removing resultant reaction pro-ducts from the reaction zone and supplying the same to a fractionating zone without passage thereof through the catalyst supply zone, and fractionat ing the products in the fractionating zone to re cover the isomerized hydrocarbon therefrom. 4. An isomerization process which comprises subjecting an isomerizable saturated hydrocar bon to catalytic isomerization in the presence of hydrogen chloride in a reaction zone containing a solid packing material and maintained under effecting ‘ said catalytic isomerization~ being sup plied to the reactionA zone in said solution, re movingfresult'ant reaction products from Isaid zone> and recovering the isomerized hydrocarbon therefrom. 6. A~process for isomerizing an -isom'erizable saturated hydrocarbon which comprises heating 'a liquid stream comprising a'portion of said'hy drocarbon to a temperature sufficient to dissolve aluminum chloride therein and then passing the heated stream in substantially liquid phase through a bed of fresh aluminum chloride to dis 60 solve a portion of said' bed, introducing the re sultant aluminum chloride-hydrocarbon solu tion and hydrogen chloride to a reaction zone containing a solid packing material, separately heatingaJ second portion of said hydrocarbonv to .a higher temperature than the ñrst-mentioned portionV and then introducing the same directly tothe reaction zone, the amount and tempera isomerizing conditie-ns, maintaining in a catalyst ture of, said separately heated second portion be supply zone a bed of- fresh aluminum chloride lng suñicient to maintain an. isomerizing tem catalyst not previously used in said reaction zone, 70 perature in the reaction zone, depositing .alumi heating a liquid stream of said isomerizable sat num. chloride oatalystffrom said solution onto urated hydrocarbon to a temperature'sufficient said solid packing material to- maintain in the to dissolve aluminum chloride therein, thereafter reaction zone an aluminum- chloride concentra passing the heated stream in substantially liquid tion substantially greater thanv that :of said. so phase through said bed in the supply zone and lution, effecting substantial isomerization'of said *2,412,675 . portions of the hydrocarbon ín the presence of the aluminum chloride catalyst thus retained in the reaction zone, substantially all of the requisite quantity of fresh aluminum chloride catalyst for effecting said catalytic isomerìzation being sup plied to the reaction zone in said solution, re moving resultant reaction products from said zone and recovering the isomerized hydrocarbon therefrom. 10 7. The process as defined in claim 3 further' characterized in that said saturated hydrocarbon is a normal paraffin. 8. The process as defined in claim 3 further characterized in that said saturated hydrocarbon is normal butane. JOSEPH D. DANFORTH.