US2408753A - Treatment of hydrocarbons - Google Patents

Description

. unitary Patented on. e, Y1946 Y TREATMENT F HYDEocARoNs Robert E. Burk, Cleveland Heights, Ohio, assignor to The Standard Oil Company,

Cleveland,

Ohio, a corporation of Ohio Application June 22, 1943, Serial No. 491,755 s claims. (ol. 26o- 671) This invention relates to the treatment of hydrocarbon stocks to form alkyl aromatics such as ethyl benzene and iso-propyl benzene, and also branched chain aliphatics such as iso-hexanes, iso-heptanes, and iso-octanes, all of which are valuable for use as an aviation gasoline base stock, with lead tetraethyl, or blended vwith other stocks or in ratios other than those of normal recovery. f

More particularly, the invention comprises a process in which hydrocarbons are cracked so as to form an ethylene and propylene containing fraction, an aromatic containing fraction, and a butane and pentane containing fraction; and the first fraction combined with the latter two fractions through appropriate alkylation and isomerization and alkylation procedures, respectively.

It is an object of the invention to provide a unitary process for alkylating aromatics and (isomerized) aliphatics formed 'inv the same cracking process-by means of olens also formed in said cracking process, so as to utilize a substantial portionof the hydrocarbons formed in cracking to provide products of the greatest value for motor fuel purposes. A further object of the invention isfto provide aprocess in which essentially the same catalytic material may be used for the isomerization and both of the alkylations, and which material comprises essentially hydrogen fluoride and boron trifluoride. i

Still a further object of the invention is the provision of a process in which the catalyst used in theisomerizing and `alkylating is not deleteriously affected by the products of the cracking operation, and which catalyst can be recovered continuously andreused in the isomerization and either or both of the alkylations.

A An additional object of the invention is the provision of a process in'which the catalyst used in one alkylation may be transferred to and used in the other alkylation before separation of the catalyst from the off-gas.

` Still a further object of the invention is to provide a process oi great flexibility in which the oleiins may be used selectively for alkylating either the aromatics or the iso-paraiiins, i. e., the ethylene may be reacted with the aromatics and the prcpylene with the iso-parafns, or the ethylene reacted with the iso-paralns and the propylene with the aromatics, or in which both olens may be reacted with both the aromatics and iso-parafiins. f

. 'A further object of the invention is the provil diately quenched with water sion of a process in which a single catalyst recovery system may be used for the isomerization and both the alkylation processes to separate the catalyst from the off-gas and make it available i or reuse.

Other objects of the invention will be apparent from the following description of an illustrative example which is to be read in connection with the sheet of drawings forming a part of the specification.

The cracking and separation of cracked products the invention, a cracking drastic cracking, i. e., a high temperature for a relatively short time. The stock may vary from the lower gasoline range to the kerosene range, although different stocks will yield somewhat different products, and in different amounts when cracked, and the stock may be selectedl with this in View, The temperature may vary from about 1250 to 1750 F., depending In accordance with stock is subjected to on the stock, the-cracking time, and the relative y amounts of the products wanted. The time may vary from about 0.1 to 0.25 seconds depending on the stock, the temperature, and the relative amounts'of the products wanted. The pressure may vary from about atmospheric to about 300 pounds per square inch depending on the other variables noted above.

The stock is fed through an inlet I, to the which it is immeor oil in the conduit 3, and fed to the tower 5. If the quench is oil it is removed at 6 with any other condensate.

cracking furnace 2, following The vapor leaves the tower 5 through a conduit 1 and is subjected to a Water quench as it moves to the tower 8. The water is removed for the most part at 9.

The hydrocarbons formed in the cracking operation are fractionated in the tower 8, the major portion of the gaseous products leaving the top at I0, where they are compressed by the pump II and sent to the tower I2, where the C3 and lighter hydrocarbons are removed from the top at I3 asa gas and sent to the supply line I4. The C4 and heavier hydrocarbons are removed from the tower 8 through the conduit I5 and sent to the tower I8 by the conduit I1. Any C4 and heavier hydrocarbons separated in the tower I2 may be added at I6 and sent to the tower I8.

The tower I8 serves to separate the Ce and heavier hydrocarbons from the Cs and lighter hydrocarbons. The Ce and heavier hydrocarbons are removed at I9, and the C5 and lighter hydrocarbons are sent to the tower 20 where any remay be returned by adjusting the valves 21 andl 28, and sent to a separate cracking furnace perated at about 20 to 50 F. higher than the temperature of the furnace 2L forfur-ther cracking. The products from thissecond' cracking furnace may be fractionated in the manner de'- scribed and the C5, C4 and lighter' hydrocarbons added to the respective supply lines 22, 26 and i4, The C5 and higher hydrocarbons are fed to the supply line Z 9.

lint accordance with anillustrative example, the cracking stock: may be a heavy naphtha, i. e., a major portion boiling within. the range of 300 to 450. F. The cracking temperature may be 1380 to 1650" E, the time of cracking about 0.175 second and' the pressure about 5 pounds per square inch. Such a cracking operation will pro.- duce products of about` the following amounts:

Weight per cent onfeed Ethylene 17 to 23 Propylene 27 to 33 Butadiene 4 to 9 Butylenes 3 to 7 Butanes 7 to 9 Pentanes 4 to 6 Benzene 7 to 13 Toluene 3 to 5 Xylenes 2 to 4 The ethylene and prop-ylenel are fed into the supply line t4, and to a suitableV gas holder Ma, from' which they may be withdrawn and used in the a'lkylation processes tobe described. The C4 and'v C5 hydrocarbons are sent to their respective storage tanks 35 and Si. If desired the fract-icnator 2i may be omitted and the C4 and C5 hydrocarbons treated as a single fraction and lsent to-a common storage tank.

The Cs and higher fraction contains a substantialV amount of benzene (C5), toluene (C1) and xylenes (Ca). This fraction is fed from the supply line 29 tothe fractionator 52. Provision is also` made for augmenting the supply of benzene or other a-romatics which may be admitted through the valve 35;

The fractionator 52 preferably separates the benzene and toluene; the former is sent through pipe 34 to a storage supply 35 and the latter throughl pipe 36A to storage supply 37. If desired, the benzene and toluene may be separated as a single fraction and sent to a common storage supply. The Xylenes and heavier aromatics are removedY from the bottom of the fractionator 32 and sent to a fractionatorv 38. If desired, the toluene may be separated with the Xylenes and heavier aromatics. The fractionator 38 separates the wanted aromaticsgenerally the Cs, C9 and Cio aromatics, such as Xylenes, ethyl benzene, iso-propyl benzene, ethyl methyl benzene, diethyl' benzene, methyl iso-propyl benzene, etc., and they are removed through the conduit 39 and sent to storage 4d. The C7 hydrocarbons may be included in the wanted products depending on the operation of theV fractionators 32 and 38. The heavier alkylate is removed at lll and may be turned: to the further cracked, dealkylated or otherwise used or disposed of.

The amg/lation of aromatzcs 7 triiluoride.v

For illustrative purposes, it may be assumed that, the benzene is to be alkylated. Benzene is fed through conduit 42 to the aromatic alkylator 432. rihe valve 44 is opened and the valve 45 is closed. The mixture containing ethylene and propylenerisv admitted to the alkylator 43 through pipe- 46., The catalyst. is. admitted through the conduit 471, valve 48 and conduit 49. Since the propylene. is more reactive they conditions may be adjusted' sov that only thev propylene will react and the.I product formed Will. be primarily isopropyl benzene (cumene). This is removed at lfandY returned at 5| for fractionation so that the alkylate ends as one of the Wanted products in theY storage. 4l). The amount of benzene in the alkylator 43A generally is in excess of the stoichiometric amount of propylene to be reacted, and` the unreacted benzene may be recycled through the conduit 50, fractionated and realkylating zone through conduits 34` and`42. The unreacted ethylene. and the catalyst are removed from the alkylator at 52. Valves 54, 51 and 58a are closed andvalves- 53, 58- andY 58, are open sothat ethylene and the catalyst passte the conduit 59 to be used in the alkylation of isopara-fns to bel described later.

The olefin containing gas and the benzene may befed tov the alkylator 43, concurrent, countercurrent or both;V Under the preferred conditions the. aromatic will be in the liquid phase and the catalyst and olefin in the gaseous phase. However, all ofthe components may be in the vapor phaseor inY the liquid phase, depending primarily on the. temperature andpressure of the operation. Ina vapor phase operation, the temperature` of the reaction, under the preferred conditions, is above the boiling point of hydrogen fluoride atv the pressure used (671 F. at atmospheric. pressure-l, for example, within the range F., preferably to- 150 F. In a liquid; phase operatiom the temperature would 13e-25m 140 F.

The pressure mayA bef varied over a wide range, but under the other conditionsv preferred a pressure of atmospheric to 25o" pounds per sq. in. pressure is; utilized. Under the preferred conditions the pressure. should below enough to permit the hydrogen fluoride catalyst to be gaseous except for such as may bev dissolved inv the benf zene in the. liquidY phase'atthe temperature used.

The time; inwhich'; thereacti'on occurs will depend;upon the sizeof. the reacting vessel, and the rate and nature ofv the. flowA of. materials through it. Under the preferred', conditions' the time of reactiomiszvery shortfand is of' an order of from one-fth minute: to fifteen minutes, a time of from .20y to4300seconds being entirely satisfactory. The catalyst-used in the process, as` mentioned previously, is hydrogen fluoride promotedy bya minor proportionv of boron triiluoridel. The

or separately. However,

is collected inthe receiver 1I. fwill be gaseous boron I through valve 65.

the vapor pressure of the hydrogen temperature of the isomerization. Boron fluoride l is dissolved in the liquefied hydrogen fluoride used -as the catalyst and the amount .dissolved depends amount of boron triuoridemay vary from a trace u'p to 50 mol per cent.- Large amountsof boron trifluoride are not required. .The amountofthe catalyst employed is Vnot critical except that a suflicient amount must be employed under topermit the reaction pletion desired. Larger amounts permit ,shorter times of reaction Aand corresponding alterations in temperature and pressure and give better yields. Under the conditions ofthe process it is preferred to employ the minimum amount that will achieve the desired Ycompleteness of the reaction. In general the amount will vary from about 2 to 50%, an amount of the order of about 4 to 15% is preferred. The ymol ratio of olefin to benzene may be about 1 m01 of olefin to 1 to 8 mols of benzene, but the higher ratios are'preferred and the excess ben-y Vzene is then recycled. f

VLAS a specific example, in which a propylene and ethylene containing gas is fed to the alkylator, and benzene is the aromatic to be alkylated, the reaction may be carried out at a temperature of 110 F. The contact time of the propylene and the benzene may be 35 seconds, the pressure may be 100 pounds per square inch. The amount of catalyst (hydrogen fluoride with a trace of boron triuoride) may be about 14% based on the benzene inthe reactor. The amounts of propylene and benzene may be 0.66 and 7.21 pounds per hour, respectively, the mol ratio of benzene to propylene being about 5.9 to 1.0. Under these conditions the iso-propyl benzene formed is about "1.03 pounds per hour. 4--While in the above examples benzene is described as the aromatic to be alkylated, toluene may be treated under the same conditions. If toluene is alkylated instead of benzene the product will be primarily methyl iso-propyl benzene; if both benzene and toluene are alkylated together, both iso-propyl benzene and methyl isopropyl benzene will be formed as the primary products. Y

The isomerization of paramns The n-butane and n-pentane in the storages -3I and 30 are isomerized to form iso-butane and iso-pentanes. These may be isomerized together separately with facility because of the simplicity of recycling the unisomerized fraction. For i1- lustrative purposes, it may be assumed that the butane is to be isomerized separately. It is removed from the storage 3l and fed through a vconduit 60 to an isomerizer B I. YCatalyst from the conduit 41 may be admitted through the valve 62a and conduit 63. A pump 63a may be included in the conduit 63 to place the catalyst under pres- The liquefied catalyst Above the liquid trifluoride under pressure. admitted to the isomerizer The isomerization is carried out preferably w'th the catalyst in the liquid phase, that is, with liquefied hydrogen fluoride .containing boron trifluoride dissolved therein.

sure and liquefy the same.

The liquid catalyst is :This is accomplished by employing a temperature for the isomerization below the boiling point of the hydrogen fluoride at the pressure employed, or in other words, a pressure at least as great as fluoride at the they can be isomerized upon the partial pressure ofthe boron fluoride and the temperature. This may be increased, if desired, by the pump 64a in the conduit 64 and the boron trifluoride admitted. through the valve.

- the mixture is transferred to a separator 62 in which the hydrocarbons separate as an upperV layer and the catalyst separates as a lower layer.

Generally, the stratification may be accomplishedV by settling, but centrifuging or other separating techniques may be employed.

The lower catalyst layer (which may be an emulsion of catalyst and hydrocarbon) is withdrawn inthe conduit 63h and returned through the conduit 64b to the isomerizer 6I where it malr be reused. In this way it will be apparent that large quantities of fresh catalyst are notl required, but such as `may be necessary can be admitted through the valves E5 and 65a. If the lower layer builds up with hydrocarbons, particularly unsaturates which may form a complex with thecatalyst, a portion of the lower layer may -be withdrawn, the catalyst removed therefrom by heating, and the catalyst returned to the conduit 4l on any of the zones in which it is used.

The upper layer containing substantial portionsof iso-butane iswithdrawn from the separator 62 through the conduit 6B, and transferred .to the fractionator 61 in which the iso-butane is removed at the top and transferred through the conduit 68 to the iso-paraffin alkylator 69. The n-butane not isomerized is withdrawn from the fractionator 61 by means of the conduit 10 and returned to the isomerizer 6I through the conduit 64b.

Provision is also made to admit an additional quantity of normal butane through the valve 12 if the amount obtained in the cracking process is not sulclent to utilize all of the olefin formed during cracking. Y

As has been mentioned previously, the isomerization preferably is carried out under suicient pressure to maintain the butane and the catalyst in .the liquid phase at the isomerizing temperature employed. This pressure is preferably accomplished by utilizing relatively high partial pressures of boron trifluoride and this partial pressure may be from 25 up .to 550 pounds per square inch. Since the catalytic activity ofthe catalyst depends in part upon the amount of boron triiluoride, the activity may be controlled n perature, pressure, amount by regulating the partial pressure of the boron trifluoride. The amount of catalyst 'used may vary depending upon the speed of the reaction desired; in general, from 25 to 100 volume per cent of the catalyst based on the hydrocarbon is preferred. TheY temperature may vary from a relatively low figure, for example, --25o F. up to 215 F. Higher temperatures, however, not only require increased pressure to maintain the liquid phase but also tend to undesirable cracking. The lengthl of time to which the hydrocarbon is subjected to the isomerizing catalyst may vary depending upon the extent of isomerization desired in a single pass. Inasmuch as provision is made for recycling, it may be more eiiicient to carry out the reaction for shorter periods accompanied by greater recycling; a period of from 15 minutes to 3 hours is preferred. l

It should also be understood that the temof catalyst, amount of lboron triuoride and .the time of treatment are more or less. interrelated' and that any one vari.- ableshould be. selected and adjustedv with reference to the others for the most encient operation. This consideration, however, goes only to eiliciency and yields and not operability and, therefore, may be adjusted by those skilled in the: art in. view of .the descrption'herein.

As an illustrative example', n-butane may be subjected tothe catalytic' action of 50 volume per cent' of liquid'v hydrogen iluoride in which is dissolved' boron trifluoride in an amount as ,to provide a partial pressure ofA boron triuoride of 300' pounds per square. inch'. Isomerization may be carried on for two hours at a temperature of 122 E'. The producty is found to contain about 27 per cent iso-butane.

The above processhas. been described particularly with reference to the isomerization of bu- .tane but it may be carriedout in the same way with pentane. In this event pentane is withdrawn. from storage 30 and treated in the same manner as previously described.

If .the butano and pentane have not been separated. by a fractionator such as shown at 2'I so the normal hydrocarbon for isomerization is a mixture, or if it is desired to isomerize both the butane and pentane simultaneously by withdrawing from both the storages 30 and 3|, .this :can also be accomplished in Ithe same manner described previously. Under such circumstances, however, it is desirable tov utilize an additional fractionator .to separate the: iso-butane and isopentane from the normal butane and, normal pentane after isomerizationso that both of .the unisornerized, normal hydrocarbons may be returnedthrough. the conduit 'lll for further isomerization.

Allcylatzon of iso-butano and/or iso-pedirme The iso-parafns isomerized in the manner" described previously are. then. alkylated with. an olefin. In the following illustrative. example it is assumed that the n-butane has been i'somerized separately and that the iso-butane4 will be. alkylated separately. The iso-butane coming. from the fra'ctionator 6l is introduced into the. alkyl'- ator 69 through the conduit. 63. Inasmuch as the alkylaton preferably is carried' out 'm the liquid. phase, the catalyst may be introduced in the liquid phasefrom. the receiver Il through. the valve T3. The olefin used for the alkylation. in this example is. the ethylene and catalyst containing gas left over from. the alkylation of. the aromatics, and which. existsy from. the. aromatic alkylator 43 through conduit 52 and valves: 53.-, 56, 58 and conduit 59. A. pump 'I5 maybe. provided to liquefy .the hydrogen fluoride and place the boron fluoride under the propel' pressure". Since in the illustrative example the propylene will have been used inr allrylatingY thearomatics, the product formed in the alkylation of iso-butane with the remaining ethylene. will? be the isomeric hexanes.

The alkylation is accomplished by mixing the iso-butano withV the catalyst in'. the liquid phase in the presence of the olen; after'the reaction has proceeded to the desired extent, the mixture is transferred to ythe separator 1S wherev the hydrocarbon and catalyst are separated preferably by gravity straticati'on. The separa-tedA catalyst layer (which may be a hydrocarbon-catalyst emulsion) may be returned' through the conduit "I7 to .the alkylat'or 69 and reused. In this way relatively small amounts of fresh catalyst are required from the supply 1|, If the 'catalyst layer builds uptoo muchl in the form. off a catalysthydrocarbon complex, a portion. may be withdrawn and the catalyst removedz therefrom. by heating and' the catalyst returned .to the conduit 't1 or any of the zones utilizing the catalyst..

The upperV layer containing the alkylated products is withdrawn from the separator 'I6 through a conduit 'I3 and transferred to the fra'ctionator 19". The'alkylated products are-separated at the bottom of the fractionator through a. conduit and sentito storage.v Since the amount of iso-butaneused preferably exceeds the amount stoichiometrically required; for reaction withA olens. provision. is made for recyling the excess iso-butane through the conduit. 8l tothe alkylator 69.

The butano fraction in the storage. 3 I' alsomay contain butylenes, and if so, these may alkylate with the iso-butano in the isomerizer 6l.. Provision is made for withdrawing such alkylates. at the bottom of the fractionator 61- through the conduit 82 and transferring them through the conduit lliV where they are separated with the wanted alkylatedproductsr in the conduit 80.

The alkylation reaction preferably should be carried out with an excess of the. iso-paran to promote complete utilization of. the olen and repress polymerization thereof. In. general, the mol. ratioy of olen to iso-paran should be 1:2 to 12. The pressure should be sufcient to maintain the isobutane and the catalyst inthe liquid phase. This may be accomplished preferably by employing a relatively high partial pressure of boron triiluoride. The temperature. may vary from 30 up to 160 F. In general, thetemperature and partial. pressure of boron trifiuoridein the alkylation zone aret lower than in the isomerization zone. This suggestsy thatV the pump I4 may be omitted and the pressure in the supply li maintained at that desired in the alkylation. Any higher pressure for isomerization can be supplied by the pump 64a.. The length of, the reaction may vary from 15 minutes. to. 3 hours but the alkylation may be accomplished in somewhat shorter time than the isomerization. The amount of the catalyst may varyy from l0 to 100 volume per cent depending upon theY speed of the reaction. desired, temperature', and pressure. It is preferred to carryl out the' alkylation with a large amount of hydrogen fluoride and asmall amount of boron `triiluoride or a large amount of boron fluoride. and' a small amount of. hydrogen iiuoride..

The amount of boron tri-fluoride dissolved in the liquid hydrogen iiuoride depends on the pressure' and temperature andV may be expressed in terms of its partialpressure at a given temperature. The amount of. the catalyst' the proportiony of the twovv luorides, the temperature' and time. of the' reaction are morel or less' interrelatedi andY should be adjusted with referencey to each other. These adjustments arey concerned more with efciency and yields than with operability and may bey adjusted by' one skilled in the. art for the: most efci'en-t operation in view of the dis.- closures herein.

AS an illustrative example, iso-butano and ethylene. in the' proportion of about 1:0.7 mols may be reacted atv 40 F. for 1% hours in the presence of liquid hydrogen fluoride. inl the amount of 50 vol. percent of the iso-butano and an amount of boron. triuoride to provide apartial' pressure of lpoundsper. square inch; Conversion tolabout 60% in the.` gasoline. range is obtainedl The gasolinev contains: about 25% isomay iso-hexanes and iso-heptanes. boiling below 350 F.

The above example has been described utilizing isoLbutane. The process may be carriedl out under about the same conditions utilizing isopentane. For example, iso-pentane and ethylene be introduced into the alkylator E9 in the ratio of about 1:0.4 mols at 40 F. for 11/2 hours in -the presence of 60 weight per centhydrogen uoride and an amount of boron trifluoride to provide a partial pressure of 50 pounds per square inch. TheA yield shows a conversion of about 76%. About 30% is iso-butane which is recycled for alkylation, about iso-hexanes, about 17% iso-heptanes, about 10% iso-'octanes and 19% higher products, most of which are nwithin lthe gasoline range." Ii" desired a pentane may be `alkylated thesame conditions.

' Recovery of the catalyst pentanes, 36 the remainder mixture of .iso-butane" and iso together under about 'Ihe catalyst carried into the fractionator 19 with the hydrocarbon layer from the separator 16 isl removed at thetop of the fractionator 19 through Vthe conduit 83 togetherwith unreacted gases, such as C1 toCs saturates and any small amount of unreacted oleiins.. In the illustrativo example valves54 and 5 1 are closed, valve `E55 is open so that the catalyst is sent to an absorber 84through the conduit 8,5. The absorber may be .a packed column or bubble -plate column The absorbent ifs-introduced as a liquid into the top of the absorber 84 by meansofa conduit 85a. The catalyst is absorbed by or forms a loose chemical combination with theV absorbent and is removed through the conduit 8B. Any saturated C1 toACa hydrocarbons in thesupplyl line I4 v .whichhavebeen carried throughthe alkylators 43 and 69, after the catalyst .has been extracted therefrom, exit as the oir-gas in conduit-81 land may be used as fuel or for other purposes `deypending upon the composition therein. e The `absorbent charged with the catalyst and removed through the conduit86 is sent to a desorber 88 where the catalyst is removed, and sent through conduit 44| Vfor use inthe isornerizing or either of the alkylating reactions. The denuded a)'r sorbe'nt is returned through the conduit 85a Ito the absorber 84.r Y Y g The absorbent for separating the catalyst from the gas may beanyv'of a large -enumber of compounds which form a complexwithor otherwise absorb hydrogen" fluoride and, boron triiluoride..`

Hv`IElXarnples are dihydroxyiluobcric acid; substituted `and unsubstituteddiarylketones, such as beuzphenone.. amines, clic.- compounds, and other nitrogenous basic compounds suchwas, diphenylamine, `coal tar bases, and chlorinated amines; certain aromatic ,hydro- -carbfms,l ethers such as anisole `anddiphenyl ether; 'and certain metal fluorides. The temperature-under; which they absorption operation is 4carried out will depend upon the absorbent used .and -the g, pressure .conditions maintained Vand is basic nitrogen-.heterocy- .such as to secure a desirable or maximum absorpl tion.` When benzophenone is the absorbenta `teniperature;from"near the melting pointoi `the .benzophenone up to 300511'. may be used,v preferably 160 to 210 F; The desorbing may be ac- ,complished `at a higher temperature at-which the complex is destroyed at least to some extent to i'reethe catalyst in thevapor form. In the case `oi'fbenzophenone a temperature within the range 2010300 to 530 F: may .bei used for desorption.

. The products leave racteristicsof theY wanted products,

'Alternative procedures In the examples described heretofore thevpropylene isused to alkylate the aromatics,and the ethylene is utilized to alkylate the iso-lparafns. If desired, this procedure may be reversed by closing valves 44, 53, 55,-and 58 and opening valves 45, 54, 56, 51 and 58a. I

In this operation the propylene and ethylene containing supply in the line I4 is sent through the open valve 45 to the alkylator 69. The propylene being the more `reactive will be utilized to -alkylate the isofbutane and/or iso-pentane. The catalyst andunreacted ethylene will exit through the conduit 83, open valves 5l, 56; and 58a,.through the conduit 89, so that the aromatic alkylation is accomplished with the ethylene and catalyst contained therein which is admitted through the conduit 89. In this procedure it may or may not be necessary to admit additional catalyst through the valve 48 depending on the amount desired with the aromatic alkylation. the aromatic alkylator through conduit 52 whichvwill containthe saturatedgases and the catalyst which will be sent throughrvalve 54, conduit and the catalyst will be absorbed and desorbed in the absorber 84 and desorber 88, respectively. In this operation the iso-paraiiins`V alkylated withy the propylene will have a slightly higher molecular weight.v For example, if iso-butane is alkylated with propylene the product will consist primarily of isomeric heptanes,'such as'2,2l,3trimethyl butane. The product formed in the alkylation of the aromatics will be primarily ethyl benzene.

'Additional alternative procedures' r If desired, both valves 44 and 45 may be opened and the mixture of ethylene and propylene fed to both ofthe alkylation zones. 'Ihe alkylation in each zone may be suiiiciently vigorous to re-. act both the propylene and ethylene in each zone so that the products exiting through the conduits 52 and 83 contain nothing but the saturated gases and catalyst. In this event, valves 53 and 51 are closed, valves 54 and 55are opened so that the catalyst from both alkylators is sent tothe ab-v sorber 84. Si. IIt, willbe apparentin view -of theabove description that'the process is `extremely flexible in the mode of operation andthe productsto be obtained. In.- general, the manneriny which the process is operated will depend uponthecharv the mehrer iniwhichthe alkylated aromatics and alkylated isofparains are to be blended either together or separately for products ofhigh anti-knock gaso-A line. l

The process has the additional advantage in that a singlecatalyst may be used for both isomerization and alkylation reactions and maybe continuously reused and recycled through the various zones depending on the relative 'requirements of each.

The process has stantially all of the the advantage of utilizing sub. useful products of the vcracking to form highly desirable final products. In general, the cracking may be conducted'so` that the ,proportion of the aromatics and aliphatics to be isomerized and/or alkylated maywcorre-,- spond. stoichiometrically with the oleflns formed by cracking and to be used in the alkylation processes. v l

It will be understood that the description of the invention is illustrative of a process and that the drawing is to facilitate an understanding of the process. It is not intended to show apparatus either in form or scale that is necessarily suitable for practicing the invention. Similarly lno attempt is made to include all of the heaters, condensers, pumps and other apparatus that may be necessary, as all of these features will be apparent to one skilled in the art in View of' lthe explanation of the process herein. c

The invention is capable of many modincations in the details of operation, as will be apparent to one skilled in the art, and all such modications are to be included as arewithin the scope of the following claims.

Iclaim: Y

1. The process which comprises heating hydrocarbons to a relatively high temperature lfor a short time to form ethylene and propylene,- C4 and C aliphatic Ahydrocarbons, and aromatics, separating Athe C3 and lighter hydrocarbons containing propylene and ethylene, an aliphatic fraction selected from the group consisting of C4 hydrocarbons, C5 hydrocarbons and a mixture thereof and comprising a normal parainic hydrocarbon, and a Cs and heavier hydrocarbon fraction containing aromatics; introducing the propylene and ethylene containing fraction and the aromatics into an alkylation zone and reacting the propylene with at least a part of the aromatics, isomerizing at least part of the normal parainic hydrocarbon in the aliphatic fraction, transferring the ethylene from the iirst alkylation zone and alkylating the isomerized hydrocarbon with the ethylene.

2. A process in accordance with claim 1 in which the isomerization and both alkylations are carried out in the presence of a catalyst comprising hydrogen fluoride and boron triuoride.

3. The process which comprises heating hydrocarbons to a relatively high temperature for a short time to form ethylene and propylene, C4 and C5 aliphatic hydrocarbons, and aromatics, separating the C3 and lighter hydrocarbons containing propylene and ethyleneJ an aliphatic fraction selected from vthe group consisting of C4 hydrocarbons, C5 hydrocarbons and a mixture thereof and comprising a normal parafnic hydrocarbon, and a Cs and heavier hydrocarbon fraction containing aromatics, isomerizing at least part of the normal parainic hydrocarbon in the aliphatic `fraction, introducing the propylene and ethylene containing fraction and the isomerized hydrocarbon into an alkylating zone, and alkylating the isomerized hydrocarbon with the propylene contained in the lighterwfraction, transferring the unreacted ethylene and introducing it and at least part of the aromatics into a second alkylation zone and alkylating said aromatics with the ethylene.

4. A process in accordance with claim 3 in which the isomerization and both alkylations are carried out in the presence of a catalyst comprising hydrogen uoride and boron triiuoride.

5. The process which comprises heating a hydrocarbon stock boiling in the gasoline-kerosene range to a temperature Within the range of about 1250c to 1'750 for a time within the range of about 0.1 to 0.25 second to crack said hydrocarbon stock and form ethylene and propylene, aliphatic hydrocarbons in the butane-pentane range, and aromatics, fractionating the products to yield a C3 and lighter hydrocarbon fraction containing propylene and ethylene, an aliphatic hydrocarbon fraction boiling in the butanepentane range and comprising a normal parainic hydrocarbon, and a C6 and heavier hydrocarbon fraction containing aromatics; intro- 5 ducing atleast part of the aromatic containing fraction and the lighter propylene and ethylene containing fraction into any alkylating zone and reacting the propylene with at least a part of the aromatic in the presence of a catalyst com# prising hydrogen fluoride and boron triiiuoride at a temperature of 80 to 210 F'., and at .a pressure of up to 250 pounds per square inch but not more than that necessary to maintain the catalyst in the vapor phase,A withdrawing the unreacted ethylene in admixture with catalyst, isomerizing the Vnormal parafnic hydrocarbon in the aliphatic containing fraction-at a temperature of 30 F'. to 215 F. in the presence of a catalyst comprising liquid hydrogen uoride in which is dissolved boron triiluoride under a partial pressure of 50 to 550 pounds per square inch, separating the isomer and transferring it to a second alkylation zone, introducing the unreacted ethylene and catalyst withdrawn from the first alkylation zone into the second alkylation zone, alkylating the isomer at a temperature of to 160A F. in the presence of liquid hydrogen fluoride containing dissolved boron' fluoride under a partial pressure of to 200 pounds per square inch, transferring Vthe funre'acted products of the lighterfraction and catalyst contained in the same to a recovery zone, separating the catalyst from the 'unreactedlighter products, and returning the catalyst for reuse.

6. The process which comprises heating a heavy naphtha hydrocarbon stock to `a temperature within the range of about 1380 to 1650 F., for about 0.175 second to crack .said hydrocarbon stock and form ethylene and propylene, aliphatic hydrocarbons in the butane-pentane range, and aromatics, fractionating the products to yield a C3 and lighter hydrocarbon fraction containing propylene and ethylene,A an aliphatic hydrocarbon fraction boiling inV the butane-pentane range 4'5 and comprising a normal paraiiinic hydrocarbon,

and a Cs and heavier hydrocarbon vfraction containing aromaticsintroducing at least part of the aromatic containing fraction and the lighter propylene and ethylene containing vfraction into 50 an alkylating zone and reacting the propylene with at least a part of the aromatic in the presence of a catalyst comprising hydrogen fluoride and boron triuoride'at a temperature of 90 to 150 and at a ypressurenof about80 to 150 V pounds per square inch, withdrawing the unreac'ted ethylene Iin admixture 'With catalyst, isomerizing the normal parafinic hydrocarbon in the' aliphatic containing fraction at a temperature of 65 to 160 in thepresence of a catalyst comprising 25 to 100 volume per cent liquid hydrogen fluoride (based on rthe hydrocarbon) in which is dissolved boron trifiuoride under a partial pressure of 150 to 350 pounds per square inch, separating the isomer andtran'sferring it to a second alkylation zone, introducing the unreacted ethylene and catalyst Withdrawn from the 'rst alkylation zone' into the second alkylation zone, the isomer being stoichiometrically in excess of the ethylene, alkylating the isomer at a temperature of 10v to 105 F.

in' thepresence of liquid hydrogenuoride containing dissolved .boron fluoride under a partial pressure of 50 to 200 'pounds per square inch, recycling the unreacted' isomer, @withdrawing the alkylated products," transferring the unreacted products of the lighter fraction and catalyst contained in the same and contacting them with an absorbent, desorbing the catalyst from the absorbent, and returning the catalyst; for reuse.

'7. The process which comprises heating a hydrocarbon stock boiling in the gasoline-kerosene range to a temperature within the range of about 1250 to 1750 F., for a time within the range of about 0.1 to 0.25 second to crack said hydrocarbon stock and form ethylene and propylene, aliphatic hydrocarbons in the butane-pentane range, and aromatics, fractionating the products to yield a Cs and lighter hydrocarbon fraction containing propylene and ethylene, an aliphatic hydrocarbon fraction boiling in the butane-pentane range and comprising a normal parailnic hydrocarbon, and a Ce and heavier hydrocarbon fraction containing aromatics; isomerizing the normal parainic hydrocarbon in the aliphatic containing fraction at a temperature of 30 F. to 215 F. in ythe presence of a catalyst comprising liquid hydrogen iiuoride in which is dissolved boron trifluoride and under a partial pressure of 50 to 550 pounds per square inch, separating the isomer and transferring it to an alkylation zone, transferring the lighter ethylene and propylene containing fraction to the alkylation zone and reacting the propylene and at least part of the isomer at a temperature of -30 to 160 F. in the presence of liquid hydrogen fluoride containing dissolved boron uoride under a partial pressure of boron trifluoride of 50 to 200 pounds per square inch, withdrawing the unreacted ethylene in admixture with any catalyst, introducing at least part of the aromatic containing fraction and the withdrawn ethylene and catalyst into a second alkylating zone, and reacting the ethylene with at least a part of the aromatic in the presence of a catalyst comprising hydrogen fluoride and boron .trifluoride at a temperature of 80 to 210 F., and at a square inch, but not more than that which will maintain the catalyst in the vapor phase, Withdrawing the unreacted products of the lighter fraction and catalyst from zone, separating the catalyst from the unreacted lighter products, and'returning the catalyst for reuse.

pressure up to 250 pounds per the second alkylating 8. The process which comprises heating a heavy naphtha hydrocarbon stock to a temperature within the range of about 1380 to 1650 F., for a time Within the range of about 0.1 to 0.25 second to crack said hydrocarbon stock and form ethylene and propylene, aliphatic hydrocarbons in the butane-pentane range, and aromatics, fractionating the products to yield a C3 and lighter hydrocarbon fraction containing propylene and ethylene, an aliphatic hydrocarbon fraction boiling in the butane-pentane range and comprising a normal parainic hydrocarbon, and a Ce and heavier hydrocarbon fraction containing aromatics; isomerizing the normal parainic hydrocarbon in the aliphatic containing fraction at a temperature of -5 F. to 160 F. in the presence of a catalyst comprising 25 to 100 volume per cent liquid hydrogen fluoride (based on the hydrocarbon) in which is dissolved boron trifluoride under a partial pressure of 150 to 350 pounds per square inch, separating the isomer and transferring it to an alkylation zone, transferring the lighter ethylene and propylene containing fraction to the alkylation zone and reacting the propylene and at least part of the isomer at a temperature of +10 to 110 F., in the presence of liquid hydrogen fluoride containing dissolved boronfluoride under a partial pressure of boron trifluoride of to 200 pounds per square inch, recycling the unreacted isomer, withdrawing the alkylated products, withdrawing the unreacted ethylene in admixture with any catalyst, introducing at least part of the aromatic containing fraction and the withdrawn ethylene and catalyst into a second alkylating zone, and reacting the ethylene with at least a part of the aromatic in the presence of a catalyst comprising hydrogen fluoride and boron triuoride at a temperature of to 150 F., and at a pressure of 80 to 150 pounds per square inch, withdrawing the unreacted products of the lighter fraction and catalyst from the second alkylation zone and contacting them with an absorbent, desorbing the catalyst from the absorbent, and returning the catalyst for reuse.

ROBERT E. BURK.

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