Патент USA US2404483код для вставки
July 23,` 1946. _ ’ , _-F, E FREY . 2,404,483 PRODUCTION .OF MOTOR-FUEL HYDROCARBONS `ATTORNEYS Patented July 23, 1946v 2,404,483 ` gUNITED STATES PATENT musici:? 2,404,483 ?RoDUcT'IoN oF MOTOR-FUEL HYDRooARBoNs Frederick E.» Frey, Bartlesville, Okla., assigner to Phillips Petroleum Company, a corporation of Delaware Application March 12, 19424, Serial No. 4311.429> 9 Claims. (Cl. 260f-683A) 1 This invention relates to the conversion of hy» drocarbons. More particularly, it relates to the production of motor-fuel hydrocarbons from rel-> atively low-boiling hydrocarbons by a process in which application hydrofluoric is a continuation-in-part acid is used as a catalyst. of my co 2 n the product usually is of lower quality in respect to octane number and is produced in lower yield than that obtained by alkylating the correspond ing isoparañins. In such alkylation processes, the hydroñuo‘ric acid eventually becomes so spent or deactivated pending application, Serial No. 426,627, filed J an by acid-'soluble and/or nuoro-organic by-pred' uary 13, 1942, and Serial No. 432,679, filed Feb ucts that it is unsuited for continued use; the spending or deactivation is especially rapid at elevated temperatures, such as those required for ruary 27, 1942. f Y An object of this invention is to convert rela tively low-boiling normal parañin hydrocarbons, the alkylation of normal parailins, Disposal of such as normal butane and/or normal pentane, the spent acid is a considerable problem, be-- to higher-boiling saturated hydrocarbons. cause of the corrosive nature of the acid; fur thermore,- heretofore no use for the spent acid Another object of this invention is to produce a motor fuel stock from relatively low-boiling 15 has been known, so that in the past it has been necessary to provide `acid-recovery steps, such paran-ins by a process in which used hydroiiuoric as distillation to recover the free hydrogen flu acid catalyst from an alkylation step is used as oride, and thermall decomposition> and distillation a catalyst for is'omerizing normal paraiiins to to liberate and recover the organically c_ombined isoparaflins suitable for use in the alkylation 20 fluorine as hydrogen fluoride. step. . The product obtained by catalytic alkylation A specific object is to combine, in a process usually consists of primary alkylation products, for converting normal butane to motor fueljan for example when alkylating isobutane with isomerizing step with an alkylating step in such butylenes the product usually consists predomi a Way that the material charged to the alkylating nantly of octanes with relatively small propor step is substantially free from normal parafûns. Another specific object is to produce a motor fuel of high octane number in increased yield and of increased volatility as compared to that which is produced by ordinary alkylation processes. , tions of low-boiling hydrocarbons such as pen tanes and hexanes. Because of this fact, it is usually' necessary to increase the volatility of the prr'aduct,` so that it may be' ‘efficiently used as in A specific object of this invention is to produce 30 aviation gasoline, by adding-„additional relatively low-boiling hydrocarbons, stitch as lsopentane and a motor> fuel stock from relatively low-boiling branched hexane's. ' parafflns by a combination isomerization-alkyla tion process in which an azeotropic mixture of hydroíiuoric acid and an isoparaliin is distilled from the e?lluent from an isomerizing step and is passed to an alkylating step. Other objects and advantages of this inven tion will be apparent from the accompanying description and discussion. Isoparaf?ns of relatively low molecular weight, such as isobutane and isopentane, can be reacted in the presence of an alkylation catalyst, such as concentrated hydroiiuoric acid, at a compara I have now found that spent or partly deacti vated hydroiluoric acid from an alkyl'ating step can be advantageously used as a catalyst inA an isomerizing step to convert relatively low-boiling normal 'paraflins such as normal butane and/or normal pentane, into isop'aïraflins, such as isobu tane and/or i's‘opentane, that are suitable for' con'à version» to` motor-fuel hydrocarbons in the alkyl' atin'g step. .I have also found that appreciableì proportions . >of motor-'fuel hydrocarbons are' formed by secondary reactions 'in this isomeriz ing step, and that these hydrocarbons can be‘ tively low reaction temperature, for example, in ' the range of 0 to 200° F., With alkylating reac 45 advantageously added to the product of the al-v kylatingÁ step to increase the yield and the vola tants such as oleiins having 3 to 5 carbon atoms tility of aviation-'grade motor fuel’. Further, I per molecule and corresponding alkyl compounds have found that from the effluent from suchV a such as alkyl halides, alcohols, ethers, esters, and conversion can» be distilled. a low-boiling or' azeo the like, preferably those of secondary or tertiary tropic'mix'ture ‘comprisingv isobutane and hydro~ structure, to produce hydrocarbons in the motor fuel range which have high antiknock values and -that are suitable for use in aviation gasoline. Normal paraflins, such as normal butane and nor mal pentane, can, alsol be alkylated„but only un der considerably more drasticv conditions, so that gen fluoride, which 'is' suitable for use as feed material to' an alkylating. stepl ~ In one speciñc embodiment, for example, the present invention comprises isomerizin'g normal butane by' the ison'ieriz'ingv action of hydroflùorí'c 2,404,483 3 acid previously used in an alkylation step, using the resulting isobutane for conversion to motor vantageous in order to favor the desired olefin isopara?in junctures, or alkylation reactions, and ‘V fuel hydrocarbons by hydroñuoric acid-catalyzed to hinder undesirable olefin-olefin junctures, or polymerization reactions. Preferred operating alkylation, and combining the products boiling above the butane range in such manner as to conditions in alkylator I5 are a temperature in the range of 30 to 150° F., a pressure sufficient to l obtain a motor fuel of desirably high anti-knock rating and volatility»-` . ~ maintain allcomponents in the liquid phase,~ and L An advantageous feature of my invention is ’an ` a' reaction'time of about' l'to 30 or 'more min azeotropic-distillation step, interpositionedy be utes; but if desired other conditions may be used tween an isomerizing step and an alkylating step, î 510 ¿in_îiparticular cases without passing beyond the for separating isobutane and lighter _hydrocar „bons from v’normal vbutane and heavier"hydro-gL ' ' carbons. _ scope of> this invention. ',TheJjres'ulting mixture passes through conduit By this particular step, an eflìcient'" ' 25'having valve 26 to separator 2l, wherein it is : - effected separation with of aisobutane minimum from of .-lfractionating' Ínormal, butanejs"-equip i5 _separated'into two liquid phases as by cooling and gravitational or’ centrifugal means. ment. The resulting overhead mixture com The heavier or hydroiluoric acid phase is passed prises, as well as isobutane, a substantial pro through valve 28, and conduit 29 to pump 30. If portion of hydroñuoric acid in a relatively'aètive ` ' ’i " desired, however, part of the acid may be recycled to alkylator- I5 through valve 3I and conduit 32. ‘ for and use anhydrous as catalyst condition2 in an inalkylating which it step; i'sÍs'u'itabl'é this 'Íí The lighter or hydrocarbon phase from sepa 20 l overhead mixture is'advantageously _charged di rator 21 is passed through valver33 and conduit 34 _to -Y-debutanizer 35. An overhead fraction, which is¿usual1y .predominantly isobutane but ‘ rectly to the alkylating stepwith no prior treat ‘ ment other than condensing andcoolingto a> ` suitable temperature. ` - - Another advantageous feature o_f-.my invention which at times may comprise other gases and 25 vapors,> lsuch as .hydrofluoric acid, propane, and ` liquid hydrocarbons, chiefly isopentane'and iso-f' normal butane, may be passed from debutanizer 35 through valve 36 and conduit 3l to fractionator merio hexanes, which areproduced by sideI and l0; if little or no normal butane is present, this l is the blending oflow-molecular-weight.normally 1 fraction preferably is passed directly to alkylator ï the'` alkylate produced in an alkylation step to 30 I5, as through valve 38 and conduit 39. Prefer ; increase = the volatility of the alkylate.` lThese ably also, when there is'some excess propane low-molecular-weight normally liquid hydrocar-~l and incidental _diñicultly condensible gases, such Y ‘ secondary reactions inA an isomerizing step„with ‘ bons are preferable Vto natural-gasoline fractions of a corresponding boilingrange, which are some as methane and ethane, part of the debutanizer overhead is passed through valve 40 and conduit times blended in motor fuel to increase its vola 35 4I to depropanizer 142, from which these gases are tility, because , they -comprise relatively larger passedthrough valve 46 to separator 16, and from proportions of branched-chain parañ'ins andV which the resulting 1 concentrated butanes are Y1 hencehave higher octane numbers than vthose I of the" natural-gasoline fractions.V . 1; ` . passed to fractionator I0 throughvalve 41. A normally liquid kettle product fromdebutanizer . All understandîngbflsûme; aspects of my in-v 40. 35 is passed through valve 43 and conduit 44 to vention maybe aided by a considerationof ,the rerun column 45 wherein it is separated’into two fractions: (l) a major motor-fuel fraction com prising hydrocarbons suitable for Yuse in aviation practicingthe invention and Figure 2 aschematic gasoline, which is withdrawn through outlet 48 flow-diagram. 0f . another arrangement for 4,5.. having valve 49, and (2) a bottom fraction com ‘ accompanyingdrawings, in which Figure 1 isa l schematic~flow-diagram of one arrangement for- `ticing my invention. . t . , _ prising hydrocarbons boiling above Vthe motor-fuel range, which is withdrawn through outlet> 5.0 hav ,. Referring now to Figure 1, a low-boilinghydro-~ i . h ‘ ing valve 5|.' v v carbon material, for example‘a mixture of normal butane and isobutane, is admitted to fractionator Normal butane from f_rac'tionator I0 and hy I0, as through inlet II- having valve I2 and/or 5,0. drofluoric acid from separator'21‘are forced by through conduit 3'I.> 1 By fractionator I0 it is sep-l pumps I8 and 30, respectively, through heating coil 52 to reactor 53, wherein the normal butane is isomerized to isobutane to afsubstantial extent. ‘ arated into a concentrated isobutane fraction, which is passed through valve I3 and conduit I4 , to alkylator I5, and .into anormal butane.r frac If desired, additional normal butane may be ad-‘ tion, which is passed through valve I6 and con- . 55 mitted, as through inlet 54 and valve 55; at times `duitI'I to pump I8; Y ~, 1 such normal butane may be the sole paraffin feed . In alkylator I5, the isobutane is mixed .under alkylating conditions with an alkylating reactant, § such as an olefin of three to five carbon atoms, to the process. , v I ` " In the feed to reactor 53, the ratio of hydro fluoric acid to hydrocarbon is preferably in the ‘ per molecule, preferably butylene,rwhich.may .bel 60. range of ~-`about 07.2;1 to 4:1 or Amore by weight; admitted through inlet I9 -andvvalve 20, and with- usually, operating with an acid-to-hydr'ocarbon concentrated hydrofluoric acid, preferably anhy ratio within this range will effect the maximum ` drous, which maybe admitted through inlet- 2I; and valve 22 and/or through conduit 23 asthe' l alkylation catalyst. . ' .In the composite feed to alkylator'l 5, the `weight ‘ ratio of ~isoparai‘flns to olefins, or Aotherxalkylatin'g conversion of normal paraffins to isoparañlns. The exact ratio desired for any particular case may be obtained by controlling the relative pro V portions of spent acid from separator 21 that pass through valves 28 and 3|, respectively. reactant, preferably is in the range of 2:1 to 20:11. _ The temperature in ,reactor 53 may be within i or more, andthe-weight ratioof hydrofluoric acid the „range of about 250 to 1000° F. A temperature l to total hydrocarbons preferably is in the range. 012:1 toz4z1. The olefin preferably isxìntroduced inthe range 400 to 800° F. is usually preferred; , . :into the reaction mixture under conditions of at low temperatures the rate of reaction is low, and at high temperatures some cracking and car \ high .turbulence , and/or in multipointwise. fash bon ¿formation , occurs.V ` ion, so that it' is rapidly mixed and diluted vwith withinv the range of atmosphericto 5000 pounds the isoparafûn reactant. .z ¿Thisprocedure isead The pressure may be f 75 per square inch or. more; Vusually it is preferred, f 2,404,483 .The resultingv mixtureïin'reactor IIS is passed for reasons of economy in equipment and operating costs, to use> a pressure inthe range of 250 to'2000 pounds per square inch. The reaction through valve ||9 and conduitl |2D.»to partial time may be within the range of about 1 to about' hydrocarbons Vboiling :above approximately the pentane range, heavy hydrofluoric acid-soluble condenser I2I, wherein, by a suitable cooling means, relatively high-boiling material, such as 300 minutes depending chiefly upon the temper ature; the time required decreases with increase in temperature. material, and the like, are condensed or lique If the reaction time is very ñed. Suitable conditions in partial condenser . I2 I i are a temperature in the range of 125 to 400° short, such as 1 to 5 minutes, the reaction can be ». completed in coil 52 or an .extension thereof; F. and a corresponding pressure in the range of whereupon reactor 53 may be by-passed orre 10i 15 to 400 pounds per square inch. The optimum moved from the system by means not shown. conditions. are readily determinable by trial Preferably, the reaction zoneispacked with a contact mass, such'as steel turningsyalumina, bauxite, or other material resistant to corrosion by hydrofluoric acid and> suitable for promoting the reaction and/or heat` transfer. _. . and/or from well-'known vapor-pressure rela- v tionships. of the various constituents. Condi 15 tions'outside the. ranges given above may be. used, if-desired or necessary for any particular . case. ' The resulting mixture from reactor 53 is passed 1 . , ~ ~ The Vresultingpartly liquefied mixture from through valve 56' and conduit 51 to separator 58, wherein it is separated into two liquid phases as partial condenser |2| is passed through conduit |221. and valve |23‘to separator |24, wherein it is by cooling and gravitational or centrifugal means. 205 separated into a‘ gas phase and a liquid phase. , Although the heavier or hydrofluoric acid phase. from separator 58 may be recycled to >coil 52 and/ or alkylatcr I 5„as through valve 59 and/or valve 60, at least a part of it is preferably passed through valve 6| and conduit 62 to `iractionator 63. In'this- fraction tor it is separated into (l) an overhead fraction comprising substantially The temperature and the pressure. should bev as , nearly as possible the same as those in partial condenser |2I. The »liquidphase which com 25 prises mainly . hydrocarbons and acid-soluble substances boiling approximately in the hexane range and above, is Withdrawn through valved outlet |25. The gas phase is passed through anhydrous ` hydrofluoric. acid, which is passed valve |23 andconduit |21 to condenser |28. through valve 64 and conduit >23 to alkylator I5, In condenser |28, the gas phase from separator and (2) a bottom fraction, or sludge, comprising 30 |24 is‘cooled and liquefied. The resulting liquid „ acid-soluble materials, which maybe withdrawn mixtureV of acid and hydrocarbon phases, which comprises hydrofluoric acid, isoparaiiins, and un reacted normal paraii‘ins, is passed through Valve through valved outlet 65. . The lighter or hydrocarbonphase from sepa-_ rator 58 may bel passed through valve-63 and |29"v and conduit. |30 Vto fractionating means ISI. conduit 31 to fractionator Il); however, in order 35 'Two fractions are withdrawn from fractionat to Yrecover valuable normally liquid hydrocarbons in'g means |3I'. The 4overhead fraction, which produced in the isomerizing step .by secondary re comprisesl a »low-boiling azeotropic mixture >of actions, it is preferably passed through valve 61` hydrofluoric acid Iand isobutane, and. usually and conduit E8 .to debutanizer ÍB9, »wherein it is 40 some lower-boiling material such as propane, is separated into fractions, The overhead fraction, passed through valve |32 and conduit |33 to which comprises propane, normal butane, and alkylator |34. The bottom product, which com isobutane, and generally some hydroiiuoric acid, ` prises hydrofluoric acid and hydrocarbons boil is passed through valve 10 and conduit 1| to‘de ing above isobutane, rmay be recycled in part propanizer A4,2; the bottom fraction, which com prises isopentane, hexanes, and other hydrocar bons, maybe withdrawn through outlet 12 hav ing valve 13, but is preferably passed, at least in part, through valve 14 and conduit V15, together with normally >liquid alkylation products from 45 through Avalve |35 and conduit |36 to coil II1; preferably, however, most of it is passed through valve |31 and conduit |38'to separator |39. ‘ In separator |39 the kettle fraction from frac `tionator |3I is separated into two liquid phases. The debutanizer 35, to rerun column` 45. , -lighter or hydrocarbon phase is passed through -In separator ,16. hydrofluoric acid is separated valve |40 and conduit I4Ito debutanizer |42. as a liquid phase from the overhead fraction from , The heavier'or hydrofluoric acid phase may be depropanizer 42, as by cooling and ¿gravitational passed in part through valve |43 and conduit |44 means. The acid _may- be withdrawn .through for use as catalyst in alkylator |34, but pref-k valved outlet 11, but/preferably is recycledto erably most or all'of it is recycled through valve alkylator I5` or coil 52 by _ 4 >|45 and conduit |46 to pump |I6. pane and vother light gasesare withdrawn through valved outlet 18. A part or all of the` propane 504 as by cooling andy gravitational means. In alkylatorV |34 the overhead mixture »com prising hydroñuoric acid ‘ and `isobutanle from containing fraction removed from the top of de- ` fractionator |3I is mixedv under alkylating con propanizer 42 may be passed directly to the isom 60 ditions with an .alkylating‘ reactant, >such as >an erization step :through conduit 8D, controlled by olefin having from: 3 to 5l carbon atoms per’ mole valve 8|, to conduit I1 and heater y52. ¿_ cule, or'an‘equivalent alkyl compound, which is Referring now to> Figure> >2 a suitable hydro-iv introduced‘thr'ough inlet |41 and valve |48. Since carbon material, such as amixture comprising 65 the overhead mixture usually contains insuffi chiefly normal paraiiins, preferably normal cient hydrofluoric acid'for effecting with desir butane, is admitted through inlet ||I, valve I I2, ably high emciency. the alkylation ofthe iso and pump `||3. To this hydrocarbonfmaterial butane, additional alkylation catalyst is admitted is added >hydrofluoric acid previously usedin the through inlet |49l and valve |50 Áand/or through alkylation step, from acid-recycle conduit |46, conduit |44. Such additional alkylation catalyst by pump Il_6; if desired, additional acid may be may be any of the alkylation catalysts that» are admitted throughinlet ,l I4 and ‘valvev |~-|5. The operative in the presence of hydrofluoric acid, resultant acid-hydrocarbon; mixture is ypassed Vbut for the sake of simplicity and' of eliminat through heater i|1 to reactor. I I8.4 The -oper-A ing otherwise necessary subsequent catalyst ation of heater I I1¿¿and reactor,` IIS. ,are-.,substan», segregating'steps, it may be taken to be addif. tially as described for `_heater 52 and reactor 53. . 75 2,404,483 7 tional i hydrofluoricv acid, which, is. preferred. Usually the hydroñuoric `acid admitted‘rthrough` inlet |49 may be the sole vcatalyst; feed to thel system. In the feeds . . to?alkylator . . fluoric .`acid,' is recycledïthrough valve |13 and conduit I14tothe`isomerizingrstep." The bottomfraction;v which. comprises.r low-boiling normally liquid hydrocarbons, such'as isopentane, hexanes, |34 , the weight . . ratio ., and heptanes, may‘be. Withdrawn through outlet of isobutane toV olefin, or other alkylating re-' actant, is preferably in the range of 2:1 to 20:1 |15 having valve . | 16; preferably, however, atleast ai part v‘of it is passed through valve |11 and con i or more, and the weight ratio of hydroñuoric duit |18 Vto fractionating means |60, wherein it acid to totalhydrocarbons‘is preferably in `the becomes 'blended'with the liquid alkylation prod-. ‘ >range 0.2:1 to 4:1.. The oleñn is preferably in l troduced into the reaction mixture Vunder con ‘ ditions A fejw'of the- many -aspects'of my invention are of 1 high turbulence Vand/,or ' in .multi- ‘ illustrated bythe following' examples, `which are illustrative, but not necessarilylimitative;of the pointwise fashion,„so that it is Vrapidly mixed ` with- the »isobutane. This .procedure .is advan l tageous in order to favor the desired .oleñn-iso 1 vparaffin junctures, or alkylation reactions, and to l hinder undesirable olefin-olefin junctures, invention. 15 -' " . Y " . " §"Eœamplel' ' . ' , In an arrangement similarto that illustrated in - Figure. _1, `a mixture ofl approximately equal pro or ' polymerization reactions. Preferred operating portions of "normal butane and »isobutane' is l conditions in alkylator |34 are a temperature in, the range of 30 to 150° F., a pressure suflìcient to maintain all components in the liquid phase, charged to a fractional-distillation column, from. Whiclr an overhead fraction consisting chieñy of q and a time ofaboutV 1 Vto 30 orV more minutes; i'sobutane> is passed to an alkylation step, and from l however, conditions outside of these ranges may which y a bottom fraction consistingr chieiiy of normal butane is passed to an isomerization'step. ` beyond the scope of this invention. 25 Butylenes and concentrated hydrofluoric acid are separately ‘charged to the alkylation step. In The resulting mixture passes through conduit this alkylation step, conditions are approximately i |5| and valve |52 to separator |53,\wherein_it is separated into two liquid phases as by cooling as follows: temperature, 85° F.; pressure, 125 and gravitational or centrifugal means. pounds per square inch; reaction time, 6 minutes; Part of the heavier or hydrofiuoric acid phase isobutane-to-oleñn molal ratio (in thegmaterials entering the" alkylation reactor), 10:1; hydro maybe recycled through valve. |54, conduit |55, "ïand .pump |56 to alkylator v|34;’preferably an carbon-to acid weight ratio, 1,5:1; .and rapid amount. of acid approximately equivalent to„or mixing to maintain intimate contact between the alsobe used in particular cases without passing Y lsomewhat greater than, that introduced to the acid and hydrocarbon phases. lallfzylator in the overhead fraction from frac ltionator |3| is passed through valve V|51 and alkylation catalyst. . . . The lighterv or hydrocarbon phase _ . from separator |53is passedthrough valve |58 and conduit |59 to fractionating means |60, in which. . ' . is separated by gravity intoA two liquid layers. The `conduit |46 to pump ||6 for use in thejsomeriz ing step. VIt is a particular feature of this in# ' vention that the catalyst used for effectingth'eKY isomerization reaction is Ya hydroiluoric .acid 40 , which is discharged from the alkylation step asA spent ^ Y The resulting eiiiuent fromV the alkylation step heavier `_or acid layer is passed to'the isomeriza‘ tion? step. The lighter orv hydrocarbon layeris` debutanized ; the Voverhead fraction, comprising chiefly unreacted iscbutane'and hydroi'luoric acid,V is recycled to the alkylation step; the bottom frac tion,v comprising normally liquid hydrocarbons,` ` is passed Vto >a rerun column. In theisomerization step, proximately as follows: »_ ì conditions are ap-k temperature, 500° F.; pressure, „750 pounds per square inch; time, Y4.5 it is separated into the following four fractions: (1) a low-boiling fraction comprising propane minutes;j hydrocarbonp-to-acid ratio, about 1:1 f and hydrogen fiuoride with minor proportions of t by- weight; and a contact mass comprising steelk turnings _in the reactor. incidental gases, such as methane and ethane, which may be passed through conduit | 6| and 50i. The eiiiuent from the isomerization step' isl cooled and separated into two liquid phases. The valve |62 to separator |63; (2) a major fraction comprising isobutane, which is recycled via valve heavier or acid phase'is‘fractionallyV distilled' to \ recover hydroiiuoric acid, which is returned to |64 andr conduit |33 to alkylator |34; (3) a frac the alkylation step. The lighter or hydrocarbon tion of highly branched paraiñnic reaction prod-V phase is also fractionally distilled; it has a hydro- " ucts boiling within the „motor-fuel range, whichA -` carbon ‘composition about as' follows, in‘per cent iswithdrawn through outlet1|65 having `valve |66; Vand (4) a relatively high-boiling hydro ' "by «weighty propane, 10; isobutane, 26; normal butarie, 51.; pentanes (mostly isopentane), 10;` carbon residue, which is Withdrawn through out hexanes, 3. AnVV azeotropic mixturejof propaneA let |61 having valve |58. ...Preferably to increase the over-all yield, part of the propane-rich low-V 603 and hydrofluoric acid is recycled to the yisomer ization* step; the excess propane'is withdrawn boiling fractionis recycled through valve | 69'and >from the process; the isobutane is passed to the> conduit |10 to coil |.|1 of the isomerizing step’.V `In separator |63, by cooling and gravitational alkylation step;l the normal butane isrecycled to the isomerization step; and the normally liquid means, a liquid hydroñuoric'acid phase is sepa-V rated Yout. This hydroñuoric acid phase may be material heavier than butane is passed to the withdrawn through valved outlet |1|, or it’V may rerun column. be recycled to 'alkylator |34 or to coil ||1 by means not shown in the drawings. In thevrerun column, themixture of normally lthe isomerization steps` is fractionally distilled carbon residue (gas and/or liquid) is withdrawn through valved outletY |12 and .disposed of in any suitable manner. ` ' ' _ ' In debutanizer V|42 the hydrocarbon phase'from separator |39 is separated by distillation into .two?` fractions. f Thejoverhead fraction, which' com-_ prises mostly fno'rmal’butane 'with' some lhydro-.-- liquid hydrocarbons fromboth the alkylation and toyield an overhead fraction of aviation-range l. motor-fuel hydrocarbons anda vbottom fraction of higher-boiling hydrocarbons. The yield of motor-fuel hydrocarbons is about 205 per cent byV weight of the butylenes charged to the alkylation step. The motor-fuel product-has an octane num; Aber of about 91 and a desirably high volatility'. - v ' 2,404,483 ~ .H495 _, , 1 _ Example II -10 . ’ l À scheme that Will be-obvious `to those skilled-in the art may be advantageous to facilitate the use of \- In an arrangement- `similar tothat illustrated in Figure 2, , normal `butane and concentrated such hydrofluoric acid are» charged to an isomerization Stage. , hydrofluoric »a`cid.~. Some change in¿ the' flow modiñers. . » Y ' . ` ’ Additional pumps, valves, conduits, coolers, fractionators,- and other equipment, such as are well-known in the art of hydrocarbon conversion, may be used Wherever they are necessary orcon vement for obtaining the results indicated in any _ The isomerizing conditions are approxi- - »mately as follows: temperature, 425° ’Eg-pressure, 2000 pounds per square inch `(mixed-phase or liquid-and-gas conditions); reaction time, 60 minutes; acid-to-hydrocarbon ratio, 1.521. The 10 particular case. The scope of my” invention should v resulting isomerization eiiiuent comprises a hydro not b'e unduly limited by specific numerical values carbon mixture of approximately `the following recited herein. -l " " y' vcomposition, in per cent by weight.: propane, v10; Iclaim: " Í > ~î ,Y '-f isobutane,'26;» normal butano,l 5‘1; hydrocarbons ' "11. A process' yforiproducing'n‘iotorJ-fuel hydro boiling higher than normal butane; ‘13. ' f . l 15 . From the isomerization efliuent is Withdrawn, by partial cooling and gravitational settling, a liquid product which comprises substantial pro portions of'fpentanes and hexanes.l The" remain trated hydrofluoric acid in anf -i'somerizat'ion step; separating the >eiliuent _from said is'omeri'z'af . ing material is passed to a fractionator from the vtionisft'ep by distillation intoI an overhead fraction bottomcf which amixture of hydrofluoric acid and hydrocarbons (mostly normal butane). boil ing above isobutane is recycled to the isomerizing stage, and from theïtop" of ‘which a low-boiling mixture comprising Vchiefly propane, isobutane, 'and' hydrofluoric acid is passedl to an alkylator. The composition of this low-boiling mixtureîis usually about 2'0 to 30 per cent b-y-'weight hydrogen carbone,“Which"cömprisesr yisoiií'e'riZirig a; low boilingl normal paraiìin Yof `--four Eto yiii/‘e carbon atoms per >`molecule in 'the'. "presence of >concen compri'singihydrofluoríc acid and an isoparafiin of four to five carbon'at'orns per »mt'plec‘ule,V` and into afbo'tto‘in- >fraction comprising hydroiiuoric acid and ‘a normal paraflin having 'fourtoi’ive Y25 carbon >atoms per molecule ;_ _passing Ésa'id bottom ñuoride and 70 to 80 per 'cent hydrocarbons.> Sufiicient additional or recycle'hydro?luoric acid is introduced to the alkylatorfto bring'the acid to hydrocarbon Weight Vratio up to about 1.1. A relatively small'proportion of mixed butylenes, preferablybelovsT about 20 per cent vby Weight of Y fraction to said isomerization step; 'passing said overhead fractíonvto an allrylating'step and alkyl-v a'ting'said isoparafiin `with an added alkylating reactant vinthe presence of-fsaid accompanying hydrofluoric acid toV produce motor-fuel hydro carbons; and withdrawing-the resulting motor fuel hydrocarbons. , ’ _ ‘ 2J The] process of claim 1, in vwhich said eñlu ent is freed from material boilingA approximately the'iso'butane, is introduced as alliylating reactant 35 above the pentane range by Ipartial condensation into the alkylator. prior .to said distillation. rThe conditions in the alkylatorï are as follows: temperature, 95 to 125° EL; pressure, 150 to 200 ' , 3. The process of claim 1, in which said normal parafñn is normal butane. . Y i i pounds per square inch; average reaction time, 4. A process forproducing va normally liquidy «i minutes; and rapid agitation to maintain inti 40 isoparaflinic hydrocarbon lmaterialboiling in the Y mate contact between acid and hydrocarbon motor fuel range from lower-boiling normal par phases. f afñn hydrocarbons of at least four carbon atoms The resulting efiluent mixture from the alky per molecule, which comprises subjecting such lator is passed to a settler in which it is separated a normal paraflin to catalytic isomerization in into an acid phase and a hydrocarbon phase. 45 the presence of hydrofluoric acid as the isomer Of the acid phase, a proportion equivalent to that ization catalyst to produce low-boiling isopar passing from the isomerizing stage to the alkylator is recycled to the isomerizing step; the remainder is recycled to the alkylator. The hydrocarbon aflin hydrocarbons, separating from effluents of said isomerization used hydrofluoric acid catalyst and an isobutane fraction and a volatile normally phase is passed to a fractionating means, from 50 liquid hydrocarbon fraction boiling in the motor which are obtained various products and recycle fuel range, reacting said isobutane fraction with fractions, such as those indicated on the drawings butenes under alkylation conditions and in the as being obtained from fractionation means 160. presence of said yused hydrofluoric acid catalyst The motor-fuel fraction has a clear octane num to produce irsoparafñns of higher molecular Weight ber of about 90 and is suitable for use in aviation 55 and in the motor fuel range, separating an iso gasoline. ' f paraflinic hydrocarbon fraction comprising `pyre dominantly isooctanes so produced, andblending tion, which will be obvious to those skilled in the said isooctane fraction and said volatile liquid art of hydrocarbon conversion. For example, if hydrocarbon fraction separated from the isomer the paraiiinic feed materialr comprises normal 60 ization step to produce a composite motor fuel paraflins but substantially no isoparañins, it is product. advantageously admitted in the modification of 5. A process for producing normally liquid iso Figure 1 to the isomerizingstep through inlet 5f?. paraflinic hydrocarbons from a loWer-boilingnor and Valve 55 instead of to fractionator It through mal parañin hydrocarbon of at least four carbon inlet Il and valve l2. Also, if desired, in order to 65 atoms per molecule which comprises subjecting inhibit the formation of low-boiling hydrocarbons such a normal paraiiîn in an isomerization step in the isomerizing step, a propane-rich fraction, to catalytic isomerization in the presence of ' such as that from the top of depropanizer dì’. mai7 . hydroiluoric acid as the isomerization catalyst to produce low-boiling isoparaffin hydrocarbons, be recycled to coil 52 through conduit 80 and valve 8l. Various catalyst modifiers that do 70 subjecting effluents of said isomerization to frac not enter the alkylation reaction under the pre tional distillation to produce a 10W-boiling frac There are numerous modifications of my inven vailing conditions, such as organic or inorganic ' compounds of thetype of primary halides or al cohols, polyhalides, sulfur dioxide, organic nitro gen compounds, and the like, may be added to thfy3 tion containing isobutane and hydrofluoric acid ’ and a higher-boiling fraction containing low boiling normal paraflins and hydrofluoric acid, returning said higher-boiling fraction to said iso 2,404,483 v 12v V11 merization step, passing said low-boiling fraction ' , so formed, and blending the last said hydrocar toY analkylation’step‘and reacting isobutane con#> bon fraction with the aforesaid low-boiling hy' drocarbon fraction to produce a'composite motor tained therein with an alkylating'reactant in the presenceof hydro?luoric acid as -the'lalkylation catalyst to'produce isoparafiins of higher molec ulanweight, and recovering a hydrocarbonfrac tion containing higher l boilingïisoparaflins Vso produced. ' ' ' ' " -- ' fuel stock as a product of the process. 8. A process for producing motor fuel, which comprises in combinationjalkylating isobutane with an oleñn of three to five carbon atoms vper molecule in the presence of concentrated hydro " iìuoric acidl in an `alkylation step; separating portion of the spent hydroi’luoric acid alkylation 10 from the resulting effluent from said alkylation catalystV is passed to the isomerization stepas the step a hydroñuoric acid fraction, anunreacted isobutane fraction, and a normally liquid hydro isomerization catalyst. l i ,. ~- 6. VThe process of claim 5 in which atleast a ` ' carbon fraction; >mixing »said hydroñuoric ¿acid '7. Aprocess for producing an isoparaiiinic mo Ytor Yfuel stockfcontaining both low-boiling and> fraction with normal butane; subjectingîthe’ re-. high-boiling isoparañînic hydrocarbons from low-` 15 sulting acidebutane rmixture to V"such" conditions boiling normal paraii‘lns, which comprises sub yjectingsuch anormal paraiiinto catalytic con version in the presence of hydroiiuoric acid as‘the in an isomerization step thatY said normal butane is isomerized to isobutane to'aësubstantial ex tent by hydrofluoric acid; separating l‘from the resulting eilluent from `said isomerization >step boiling.- normally liquid isoparafûns, separating> 20 used hydrofluoric acidcatalyst and an isobutane fraction, an unreacted vnormal butane Nfraction, from ellluents of said conversion a mixture Y'coniî conversion catalyst to produce isobutane and' 10W-v tainingvsubstantial quantities of yisobutane andv substantiallyanhydrous hydrofluoric acid, sep' V and a normally liquid lay-product fraction; re-V cycling said unreacted'normal Vbutanefraotion to said isomerization step; passing‘saidused hy- , aratinglalso a vlow-boiling liquid isoparañìnic - hy-` ` drocarbon fraction. »adding to said isobutanef. 25 drofluoric acid catalyst, said unreacted ilsobutane hydroñuoric acid-mixture lan alkylating reactant land' subjecting -the comb-ined mixture to alkylaîv »tion conditions Ato produce high-boiling normally liquid hydrocarbon fraction e and ’ lsaid Ynormally liquid isoparaiiîns boiling in the-motor fuel range, separatingvfrom eflluents of said alkylation spent 30 resulting normally liquid mixture a motor-fuel hydrofluoric acid catalyst and passing-at least fraction and Vsaid isobutane fraction 'toi said alkylation step; mixing together "said normally liquid llay-product fraction; separating from the fraction;v and withdrawing from the process said a substantial portion of same toV said -conver- l sion, separating-also from veilluents »of said alkyl -ation a normally liquid isoparañînicvhydrocarbon fraction- containing said high-boiling isoparamns Imotor-fuel fraction. ~ ' „ ' ,9. The process of claim 8 in which is at least one butylene. .» 35 ' »said oiefin ' FREDERICK E.