US2476750A - Process for producing motor fuel by alkylation - Google Patents

Description

July 19, 1949.

M. P. MATUSZAK PROCESS FOR PRODUCING MOTOR FUEL BY ALKYLAT'ION Filed Oct. 8, 1947 HOlV-HVdBS ISOBUTANE EOLDVHH ETHANE IOI FIG. 3

3 Sheets-Sheet 5 COOhER "fl-" M. P. MATUSZAK ATTORNEYS Patented July 19, 1949 PROCESS FOR PRODUCING MOTOR FUEL I BY ALKYLATION Maryan P. Matuszak, Bartlesville, kla., assignor to Phillips Petroleum Company, a corporation of Delaware V Application October 8, 1947, Serial No. 778,607 7 18 Claims.

. 1 This invention relates to an alkylation process. In one embodiment it relates to a method of removing reaction "by-products from the effluent of a catalytic alkylation process. In another embodiment it relates to a method of removing organically combined halogen (herein designated organic halogen), such as fluorine or chlorine from paraffin hydrocarbon materials contaminated therewith. In another embodiment it relates to an improved. method of alkylating a low-boiling paraflin, usually an isoparaffln, with an alkylating agent, usually a low boiling olefin, to make a higher-boiling parafiin (known in the art as alkylate) which is useful as a high octane base or blending stock for motor and aviation fuel. 7

This invention is a continuation-in-part of my co-pending application Serial No. 602,247, filed June 29, 1945, and now Patent No. 2,432,482. In one embodiment, it comprises, in combination, catalytic alkylation of a parafin with an alkylating agent in a first alkylation zone, subsequent addition of an excess of a relatively easily alkylatable compound of the type of benzene and catalytic alkylation thereof in a second alkylation zone with icy-products formed in the first alkylation zone, subsequent catalytic alkylationof the excess added easily alkyltable compound with added olefin in a third alkylation zone, and isolation of resultant composite alkylate boiling in the motor-fuel range as the main product of the process.

The principal object of this invention is to provide an improved alkylation process.

Another object is to provide an improved method of removing reaction by-products contained in the effluent material from a catalytic alkylation process.

Another object is to provide an improved method of removing organic halogen from parafiin hydrocarbon materials containing the same.

Another object is to provide an improved method of removing organic sulfates from parafiin hydrocarbon materials containing the same.

Another object is to provide an improved method of removing fluorine from paraifin hydrocarbon material contaminated therewith, such as alkylate made by alkylationof an isoparaifin with an olefin by means of hydrofluoric acid as a catalyst.

Numerous other objects will be obvious to one skilled in the art from the accompanying disclosure and discussion.

Ordinarily, the parafiin is an isoparafiin, selected vbecause of its relatively high reactivity,

V and expense.

and it is preferably isobutane, primarily because of its availability at relatively low cost. V The alkylating agent is usually one or .more olefins, but in some applications it may be oneor more olefin derivatives, such "as'alcoholaalkyl halides, or the like. The alkylationcatalys t may be any that is effective for promoting alkylation of the selected paraffin withthe' selected alkylating agent such as anhydrous hydrogen fluoride, sulfuric acid or others. Hydrofluorioacid is preferred for alkylation of'anisoparafiin with olefins heavier than ethylene or'with polar nonprimary alkyl compounds. When'ethylene or a primary alkyl compound is the alkylating agent, the catalyst may be advantageouslya mixture of hydrofluoric acid andjboron fluoride; this catalyst may also be used in alkylation of normal parafiins. Ordinarily, however, when a normal paraffin is being alkylated, or when the alkylat ing agent is ethylene; the preferred catalyst is one comprising aluminum chloride or bromide, promoted with an alkyl halide or a hydrogen halide, usually hydrogen chloride,"as in the com mercial manufacture of diisopropyl and other hydrocarbons from isobutaneand ethylene.

In the paraflin-alkylation step, conditionsfor which depend uponthe particular reactants and catalyst and may be selected in accordance'with knowledge available to the art, some undesired by-products are formed, resultin in objectionable consumption of reactants or catalyst, or both, and in objectionable contamination of the product and the surviving reactants. The principal by-products are compounds or complexes formed from hydrocarbons and alkylation catalyst, polymers formed from alkylating agent, and heavy alkylates that boil above the desired motor-fuel range} The proportions of these undesired by-products, and, even their identities. depend considerablyupon the particular materials and the particular conditions present, but their formation has' long been recognized for every catalytic parafiin-alkylation process no matter whether the catalyst comprises hydrofiuoric acid, aluminum chloride, sulfuric acid, or any of many less widely used alkylation catalysts.

In the past, little has been done to counteract the formation of these various'undesired byproducts except to remove and withdraw the most objectionable ones at considerable trouble For example, when a halogencontaining catalyst is used, a small proportion of organic halogen appears in the alkylate and in the surviving reactantajand the'seflmaterials in consequence may be subjected to a treating step designed to remove the organic halogen, such as contacting at a suitable temperature with solid metal oxides or other materials that adsorb the organic halogen compounds, or catalyticall-y split out the halogen as the hydrogen halide, or react to form metal halides. Treating with bauxite or similar material ex emplifies such a treating step for removing a halogen like chlorine or fluorine. When fluorine is the halogen, considerable diiiiculty arises because of the formation of silicon tetraiiuoride from silica present in the bauxite or similar contacting agent; the silicon tetrafiuoride is carried along in the hydrocarbon stream and subsequently causes trouble by becoming hydrolyzed by moisture, forming silicic acid that plugs equipment and necessitates expensive shutdowns for removal. Eliminating or minimizing the formation oi the organic halogen compounds is obviously highly desirable Similarly, coun teracting the formations: other undesired by products is highly desirable.

In the process ,of this invention, substantial counteracting of the formation of lay-products is obtained by fmix'injgiwith the alkylation reaction mixture, after the Ip'araflin alkylation is substantially completed, an "excess of a relatively easily alkylatable compound. compound, in the presence of the alkylation catalyst, undergoes alkylation with any surviving alkylating agent added as such and with various by-products of the paladin alkylation. Afprocess utilizing somewhat similar alkyla'tion and directed primarily to reduction bf organic halogen, has been described in co-pending application Serial No. 602,247,1'filed June 29, '194 5,'a1l1dnow Patent No. 2,432,482. In the process or the present invention, in partial contrast, a relatively larger proportion "of easily alkylatable compound is required, to react "primarily with the by-products other than, for example, organic halogen compounds'; -furthe'ririoi e, the present process is broader than that of my above mentioned copending application in that-it may be applied to 1 halogen-"free systems, although reduction of organic halogen is'no't to be excluded in particular applications. When organic halogen compounds are present, the organic halogen 'is liberated as hydrogen halide, which becomes available for reuse; simultaneously, the added easily alkylatable compound bec'o'm''s alkylated. Similar reactions occur with other catalyst-hydrocarbon compounds or complexes; for example,v when suliuric acid is the catalyst, 'by-product alkyl sulfates or 'bi'sulfates alkylate'the added compound with'regeheiation df'sulfuric acid. In somewhat analogous ta'sh'io'n, other by-products are consumed in alkyl'atin'gthe added easily alkylatable compound; such materials as polymers, so-called acid-solubleoil'formed in hydrofluoric acid and low-boiling easily alkylatable aromatic hydrocarbons that may be formed, for example, in cracking steps generally constitutes a highly satisfactory compound and may be preferred because of ready availability at low cost. Especially advantageous is such a material when it is already being used for blending with motor-fuel hydrocarbons produced by paraffin alkylation, for then there is substantially no additional cost for o the added easily alkylatable compound. However,

other compounds may be suitably utilizable in particular applications of the process. Among compounds that may be used in this way are iuran, phenol, pyrrol, thiophene, and similar alkylatable compounds that may be characterized as having at least two conjugated double bonds in a ring; but usually benzene or other low-boiling aromatic hydrocarbon, such as toluene, is preferable because of the absence of an element other than carbon and hydrogen. 7

Intimate mixing of the added compound with the paraiiin-alkylation reaction mixture, including an alkylation catalyst, is essential. The mixing period required depends upon the added compound, upon the reactivity of the various paraffinalkylation by-products, and upon the activity of the catalyst, but a suitable period, which is ordinarily measurable in minutes, usually in the range of 1 to 20 minutes, can be readily found by trial for any specific application. In general, the conditions are simil'art'o those in the .para'ffinalkylation step, so that heating, cooling, 'or other special conditioning is not necessary though such conditioning may be advantageous in particular 7 applications. In some aprilicationsgspecial mixing means may be unnecessary, provided that the added compound is adequately dis'persedinto the reaction mixture eflluerit from the 'paraffinalkylation zone, as by ejection from one or more jets; in such applications, substantial -alkylation of the added compound occurs during passage :of the reaction mixture to the next step, especially when baiiies are provided to maintain intimate mixing during this passage. Preferably, the added compound should not be present within the parafiin -alkylation zone, wherein it would compete undesirably with the paraffin "for the alkylatlng agent ied to this zone, "but traces added in recycled material may be economically permissible.

In one embodiment, the by-product-alkylation step and the preceding parafiin-alkylation step may be conducted with two separate bodies of catalyst. Although the two bodies may be of diiierent catalysts, such as hydrofluoric acid for the paramn-alkylation step and sulfuric acid for the by-product-alkylation step, it is usually preferable to have both of one catalyst. -Byuse of the two separate bodies of catalyst, anycarryover, to the paraffin alkylationstep, of surviving added compound (a. g., benzene) in solution in recycled catalyst is avoided. Such carry-over is disadvantageous to the extent that the added compound competes with the parafiin -'for the olefin or other alkylatin'g agent fed to the-process. This application requires an intermediate -separation step for separating the reaction mixture eiiluent from the paraffin-a'l-kylation step into a hydrocarbon phase, which is passed to the byproduct-alkylation step, and into'acatalystphase, which is recycled to the first step or is passed in part to a purification or catalyst-recovery system.

Regardless of whether or not a separate -body of catalyst hasbeen used, the reaction mixture efliuent from the by-product "alkylation step is passed to a final alkylation step, wherein at least part of the excess added compound is alkylated with an added olefin that is consumed so rapidly under the prevailing conditions that any objectionable by-products are negligible. When, as is preferred, the excess added compound is benzene, the olefin added in this step is preferably ethylenefree and is most preferably propylene, inasmuch as this particular olefin has a relatively small tendency to form objectionable by-products and inasmuch as the resulting alkylated benzene is mainly cumene, which is an especially desirable motor-fuel ingredient. This advantageous conversion of excess benzene to cumene results in an increased yield and in an improved quality of the motor fuel formed by the process.

The reaction mixture efiluent from the final alkylation step is passed to a settler for separation into hydrocarbon and catalyst phases. The catalyst phase is recycled to its point of original introduction into the system or is in part passed to a catalyst purification or recovery step. The hydrocarbon phase is freed from traces of catalyst and is fractionated into desired product, byproduct, and recycle fractions. If the same catalyst is used in all alkylation steps then only one catalyst regeneration system is necessary.

It will be appreciated that the final alkylation step eliminates in large measure the benzene or other relatively easily alkylatable compound from the catalyst phase. By proper adjustment of the proportion of olefin added to this step, substantially no excess or unconsumed benzene remains in the catalyst, which consequently is rendered substantially unobjectionable for use in the paraffin-alkylation step. Although use of one and the same body of catalyst for all alkylation steps presents a, need for relatively fine control, it is advantageous when equipment is limited or unobtainable in the amount required for use of two separate bodies of catalyst or when the scale of operation justifies it for economical reasons. Accordingly, such use of one body of catalyst for all alkylation steps is considered within the scope of this invention.

In the accompanying drawing Figure 1, Figure 2, Figure 3 and Figure 4 each illustrates one embodiment of my invention. Referring to Figure 1 of the drawing an alkylatable parafiin hydrocarbon is passed through line H to reactor l3. An alkylatin agent, such as an olefin, is introduced into reactor l3 through line l2 by way of line H. An alkylation catalyst, for example, an anhydrous hydrofluoric acid is introduced into reactor l3 by way of line M-. The contents of reactor l3 are maintained under alkylation conditions and are mixed by any suitable means, such as a mechanical stirrer, which is not shown. The reaction mixture eiiiuent from reactor l3 passes through line IE to reactor l8. An easily alkylatable cyclic organic compound, such as benzene, is introduced into reactor [8 by way of lines I! and H5. The contents of reactor ll are maintained under alkylation conditions and are mixed by any suitable means not shown. The reaction mixture effluent from reactor [8 passes through line l9 to reactor 22. An alkylating agent, such as an olefin, is introduced into reactor 22 by way of lines 2| and I9. The contents of reactor 22 are maintained under alkylating conditions and are mixed by any suitable means not shown. If desirable, at least a portion of the reaction mixture efliuent from reactor I8 may bypass reactor 22 by way of line 20 and enter separater 24 by Way of line 23. The'reaction mixture eiliuent from reactor 22 passes through line 23 to separator 24 where the reaction mixture is separated by gravity into a hydrocarbon phase and a catalyst phase. The catalyst phase is recycled to reactor i3 by way of lines 21, 28 and M and is reused in each of the reactors, namely l3, l8 and 22. However, at least a portion of said catalyst may be withdrawn from line 21 and passed through line 31 to catalyst purification unit 38 where the catalyst is regenerated. The purified catalyst is returned to the system through lines. 39, 28 and Hi to reactor l3. If desirable, however, at least a portion of the purified catalyst may be withdrawn from the system through line ll. The hydrocarbon phase from separator 24 passes through line 26 to fractionation unit 3 l. The unreacted parafiin in the original feed is recycled through lines 32 and H to reactor l3. However, at least a portion of this paratin recycle material may be removed from the system through line 32A. The product coming within the motor fuel boiling range is removed from the fractionation unit 3! through line 33. Any catalyst that might have been carried over from separator 24 to fractionation unit 3! is recycled through lines 34, 28 and It to reactor it. The heavy material boiling above the motor fuel boiling range is removed from fractionation unit 3| through line 36.

. Referring to Figure 2 of the drawing an alkylatable paraffin hydrocarbon is passed through line 5| to reactor 53. An alkylating agent, such as an olefin, is introduced into reactor 53 by way of lines 52 and 5!. An alkylation catalyst, such as sulfuric acid, is introduced into reactor 53 by way of line 54. The contents of reactor 53 are maintained under alkylation conditions and are mixed by any suitable means not shown. The reaction mixture effluent from reactor 53 is passed through line 56 to separator 51 where the mixture is separated by ravity into a hydrocarbon phase and a catalyst phase. The catalyst phase is recycled through lines 58 and 54 to reactor 53. However, if desirable, at least a portion of the catalyst phase may be passed from line 58 through line 83 to catalyst purification unit 86 where it is purified. The hydrocarbon phase from separator 51 passes through line 59 to reactor 62. An easily alkylatable cyclic organic compound, such as benzene, is introduced into reactor 62 by way of lines 6| and 59. A suitable alkylation catalyst, such as sulfuric acid, is introduced into reactor 62 by way of line 63. The contents of reactor 62 are maintained under alkylation conditions and are mixed by any suitable means not shown. The reaction mixture efiiuent from reactor 62 is passed through line 64 to reactor 61. An alkylating agent, such as an olefin, is introduced into reactor 61 by way of lines 66 and 64. The resulting reaction mixture is maintained under alkylating conditions in reactor 61 and is mixed by any suitable means not shown. At least a portion of the reaction mixture efiluent from reactor 62 may by-pass reactor 61 and be introduced directly into separator 63 by way of lines H and 68. The reaction mixture efiiuent from reactor 61 is passed through line 68 to separator 59 where it is separated by gravity into a hydrocarbon phase and a catalyst phase. At least a portion of the catalyst phase may be recycled through lines 12,13 and 63 to reactor 62. Also, at least a portion of the catalyst phase may pass through line E2 to catalyst purification unit 86. The hydrocarbon effluent from separator 69 passes through line 14 to fractionation unit I6.

The unreacted parafiin contained in the original feed is removed from fractionation unit 16 and recycled through lines I! and EI to reactor 53. However, at least a portion of the recycled paraffin may be removed, if desired, from the system through line HA. The product coming within the motor fuel boiling range is removed through line I8. Any higher boiling material such as tar that may be formed in the system is removed from fractionation unit I6 through line 19. Any catalyst that may be carried over into fractionation unit II; from separatorfig is removed through lines BI and at least a portion of this catalyst material may be recycled through lines 8|, 81 and 54 to reactor 53 or to reactor 62 by way of lines BI, 81 and 63, Also, at least a portion of the catalyst may be withdrawn from line BI and introduced into catalyst purification unit 86 by way of lines 82 and I2. The used catalyst which is introduced into catalyst purification unit 88 from separators 57 and B9 and from fractionation unit '16 is purified and returned to the system by way of line 81. If desired, at least a portion of the purified catalyst may be removed from the system through line 88.

Referring to Figure 3 of the drawing, a hydrocarbon suitable for cracking to produce ethylene, for example ethane, is introduced through line Illi to cracking unit I92 where it is cracked under appropriate conditions to produce ethylene. The reaction mixture effluent from cracking unit 32 is passed through line I03 to ethylene recovery unit we where the ethylene is absorbed under suitable conditions of temperature and pressure in isobutane which is introduced into the ethylene recovery unit we through line we. The light materials, such as methane and hydrogen, are removed from the ethylene recovery unit I84 through line IE1 and the materials heavier than isobutane are removed through line I023. The isobutane which contains the ethylene is removed from ethylene recovery unit I84 and is passed through line it?) to reactor III. A catalyst, such as aluminum chloride, preferably dissolved in an aluminum chloride-hydrocarbon complex, is introduced into reactor III by Way of line II 2. The contents of reactor I I I are maintained under appropriate alkylation conditions and are mixed by any suitable means not shown. The reaction mixture effluent from reactor lII passes through line M3 to separator II i where it is separated by gravity into a catalyst phase and a hydrocarbon phase. The catalyst phase is removed through line IIS and recycled to reactor III through lines II '1 and H2. However, at least a portion of the catalyst may be'removed from the system through line H5 for purification or use elsewhere, if desired. The hydrocarbon phase rom separator H4 passes through line II8 to reactor IZl. An easily alkylatable cyclic material, such as benzene, is introduced into reactor it! by way of lines H9 and IIS. Aluminum chloride catalyst, preferably dissolved in an aluminum chloride-hydrocrabon complex, is introduced into reactor I2I through line I22. The contents of reactor 52; are maintained under appropriate alkylating conditions and are mixed by any suitable means not shown. The reaction mixture ei'rluent material from reactor I2I is passed through line 223 to separator I24 where it is separated by gravity into a catalyst phase and a hydrocarbon phase. The catalyst phase is withdrawn through line I25 and at least a portion passed to a purification system not shown or for use in any manner desired; however, at least a portion of the catalyst phase is recycled to reactor I2I by Wayof lines I21 and I22. The hydrocarbon phase from reactor I24 is passed through :23 to fractionation unit I29. A recycle isobutane stream is removed from fractionation unit we and is recycled to ethylene recovery unit I06 through lines iSI and I06. However, a portion of this recycle isobutane-containing stream may be removed from the system through line I3 IA if desired. Unreacted benzene is romeved through line I32 and returned to reactor I2I by way of lines H9 and H8. The reaction product from isobutane and ethylene which comprises chiefly diisopropy-l is removed through line IM. Ethyl benzene formed is removed from fractionating unit I29 through line I36. Any high boiling product may be removed fromiractionation unit I19 through line I33.

Referring to Figure 4 of the drawing, an alkylatable paraffin hydrocarbon is introduced into the reactor column I53 through line IEI. An alkylating agent, such as an olefin, is introduced into reactor column I53 by way of lines I52 and 553. A suitable alkylation catalyst, such as sulfuric acid, is introduced through line I51 and introduced into reactor column I 53 at multiple points through lines I55, I58, H59 and IBI. The reactor column is maintained under suitable alleyletion conditions wherein the alkylation reaction takes place and the unreacted original paraffin material is taken overhead through line the and removed from the system if desired, or at least a portion of this product may be recycled through line I64, cooler I60 and line I5i to the reauctor column I53. An easily alkylatable cyclic organic compound, such as benzene, is introduced into the reactor column I53 through line 62 where it is contacted with the catalyst and reaction products of the paraffin-olefin alkylation step. The reaction mixture efiluent of reactor column I53 is passed through line I53 to separator I65. An olefin is introduced through line I65 into the reaction mixture eilluent from reactor column I53 passing through line I63 before reaching separator I 66. The total reaction mixture is separated by gravity in separator 568 into a catalyst phase and a hydrocarbon phase. The catalyst phase is recycled to the system through line I67, however at least a portion may be removed from the system through line I'S'JA and passed to a purification system not shown or used in any way desired. The hydrocarbon phase is removed from separator I65 through line I68 for further fractionation and purification as desired. Reaction column P53 is preferably operated at such temperature and. pressure that butanes and lighter hydrocarbons are removed overhead in the vapor phase and compounds heavier than butane are withdrawn as liquid kettle products.

In the accompanying diagrammatic drawing including Figures 1, 2, 3 and 4 reference to some equipment, such as pumps, gauges, and the like which obviously would be necessary to actually operate the process of my invention have been intentionally omitted. Only sufiicient equipment has been shown to illustrate the process of the invention and it is intended that no undue limitation be read into this invention by reference to the drawing and discussion thereof.

This invention may be employed in combination with steps other than a paraffin alkylation step. For example, it may be combined with a parail'in-isomerizationstep or a paraffin-disproportionation step wherein by-products are formed because of the presence of certain elements or radicals inthe catalyst used, such/as halogen or the sulfate radicals The efiiuent of such step is treated substantially ashas been described for parafiin alkylation. The term paraflin-reconstruction may be considered asbeing generic to paraffin alkylation, paraflin isomerization and paraffin-disproportionation.

Among the advantages provided by this invention by its clean-up action on any unreacted alkylating agent and on other materials such as organic halogen or organic sulfate compounds are decreased catalyst consumption; decreased expense and labor for removal of undesirable icy-products; and increasedyield of organic material suitable for use in motor fuels. The removal of olefins is desirable when normal butane for example, is removed from the reaction mixture and is subsequently catalytically isomerized to isobutane.

Example I In a continuous operation like that illustrated by Figure 2 of the drawing, isobutane is alkylated in the presence of a hydrofluoric acid catalyst with one or more olefins having mainly three to five carbon atoms per molecule. In general, substantially conventional alkylation conditions may be used, such as an isobutane-to-olefin mol ratio in the feed of approximately 4:1 to :1, a catalyst-to-hydrocarbon volume ratio of approximately0.5:1 to-2:1, a, temperature of approximately 80 to 120 'F., a titratable acidity of approximately 80 to 95 weight per cent hydrogen fluoride, a contact time or residence time of the reaction mixture in the contactor or niixerreactor of approximately 5 to 20 minutes, and a pressure adequate to maintain the reaction mixture in' liquid phase. The reaction mixture effluent from the contactor is passed to a separator for separation into hydrocarbon and catalyst phases by gravity. The catalyst phase is recycled to the isobutane-alkylation step, but part of it ordinarily is passed, continuously or intermittently, to a catalyst purification or recovery step, wherein it is subjected to fractional distillation to free it from dissolved impurities, mainly from heavy unsaturated hydrocarbons collectively known as acid-soluble oil. The hydrocarbon phase is passed to a lay-product alkylation step, wherein it is mixed-with approximately its own volume of hydrofluoric acid and with approximately 2 to 5 per cent of its own volume of refinery blending benzene having an A. P. I. gravity of approximately 30.5" and an A. S. T. M. distillation range for the first 95 per cent evaporated of approximately-167 to 177 F., which indicate a high content of benzene. This blending benzene is so called because of earlier utilization for blending with alkylate and other motor-fuel ingredients to form a high-quality aviation gasoline. Ordinary technical benzene, such as that derived from coal or from petroleum hydrocarbons byaromatization or the like may be substituted for the blending benzene. The mixing and other conditions in the by-product-alkylation step are substantially like the corresponding conditions in the paraffin-alkylation step. The reaction mixture is then passed to a third or final alkylation step, wherein it is mixed with an olefin, preferably ethylene-free and further preferably propylene, whichis added in a proportion at least equimolecular' with respect to the unconsumed benzene in the reaction mixture and preferably slightly inexcess. The conditions in this final alkylation step are gener- 10 ally similar to those in the preceding alkylation steps except that the contact time is ordinarily shorter, approximately '1- to 10 minutes, in correspondence with the relatively high reactivity of the benzene, whichappears to outweigh its relatively low concentration. Any excess olefin appears to be substantially consumed without undergoing polymerization, apparently mostly in secondary or further alkylation of benzene, accom panied by some primaryalkylation of isobutane.

As soon as the added olefin. is consumed, the reaction mixture is passed to a settler for separation into hydrocarbon and catalyst phases by gravity. The catalyst phase is recycled to the by-product-alkylation step; ordinarily little of this catalyst phase needs tofbe removed for purification. The hydrccarbonphase is passed to fractionation means for fractional distillation into various fractions. A minor low-boiling azeotropic fraction of hydrofluoric acid and isobutane may be obtained and may be passedto the byproduct-alkylation step, but ordinarily this low-. boiling material is included with a major fraction of unreactedisobutane, which is recycled to the paraffin-alkylation step. A. motor-fuel fraction is withdrawn as the main product of the process; it comprises both isoparafiinic and aromatic alkylates, including cumene, and has a desirably high quality for use in aviation gasoline. A minor fraction of high-boiling hydrocarbons is withdrawn and maybe subjected, if desired, to cracking for production of olefins.

Example II E':cample III A gaseous stream having approximately 12 mol percent ethane and 88' mol' per centpropane is subjected to cracking, yielding an eilluent having the following approximate composition, in mol 7 per cent: hydrogen, 16; methane. 30; ethylene, 24; ethane, 7; propylene,'11; propane, 11; butane and heavier, 1. 'This eflluent is cooled and is compressed to about 800 p. s. i. After being again cooled, it is subjected to absorption at approximately 40 to F. by mineral seal oil, Which removes most of the propylene and heavier hydrocarbons. .Amo'n'g'these heavier hydrocarbons is a small proportion of aromatic oils formed in the cracking step; if desired, these may be suitably recovered and subsequently used as part of the benzene inthebenzene-alkylation step. The unabsorbed gas has the followingapproximate composition, in mol per cent: hydrogen, 25; methane, 52; ethylene, 17 ethane, 5; heavier, 1. This gas ispassed to an ethylene recovery column forremoval. of hydrogenand methane and for absorption of ethylene and heavier hydrocarbons by liquid; isobutane at a pressure of approximately 500' p. s. i. and a kettle temperature of approximately 230. F. The ethylene-de nuded gas has approximately 32 and 65 mol per cent of hydrogen and methane,-respectively,"with 11 generally less than-- 3 I'nol percent of heavier hydrocarbons. The solution 'of ethylene in isobutane is passedt'o' a'first aluminum chloride-catalyzed alkylation zone, in which alkylation of isobutane with ethylene to form diisopropyl as the main product is carried out under such conditions that the yield of diisopropyl based on ethylene reacted in this step is a maximum, being usually approximately zz to 2.4 pounds of diisopropyl per pound of ethylene reacted. The conditions are interdependent to some degree and may vary somewhat, but the following may be taken as fairly typical: isobutane-to-ethylene mol ratio, approximately 4 ;1 to 6:1; volume ratio of hydrocarbon phase to catalyst phase, approximately 2:1 to 3:1; temperature, approximately 100 to 136 F. viscosityof catalyst, approximately 200 to 400 centistokes at 100 F.;resid ence time in reactor, approximately 10 to 20- minutes. The catalyst phase, which comprises aluminum chloride-hydrocarbon compounds or complexes of incompletely understood; nature, is maintained at the activity necessary to 'efiect conversion of ap proximately 90 to 94 per cent of the ethylene introduced by addition of aluminum chloride and/or hydrogen chloride or equivalent. promoter and by withdrawing some of the catalyst phase for purification or" recovery of the aluminum chloride. When the ethylene conversion reaches approximately 90- to 94 percent, the reaction mixture is passed, toe. separator system. The separated catalyst phase is returned to the reactor or is removed fpr recovery of aluminum chloride. The hydrocarbon phase is passed to a second aluminum chloride-catalyzed alkylation zone, to which is added also benzene approxi-. mately 2 to'6 times in molecular excess of the unreacted ethylene. In this zone the ethylene is substantiallycompletely consumed in alkylation of benzene to ethylbenzene. Some polyethylated benzene, mostly diethylbenzene, is also, formed, especially when the ratio of benzene to ethylene is relatively low; inaddition. a small proportion of alkylated benzene other than ethylated benzene is formed as a result of minor side reactions, which are advantageous in that they decrease the content of organic chlorine. Although the catalyst used ii -this: benzeneelkylation step is substantially identical when I fresh: to. that introduced into thezisobutane-allrylation step, being prepared for example, by mixing approximately '7 to 10 parts-by weightof kerosene and 1 part of anhydrous aluminum chloride and some hydrogen chloride at, 150 to 200 F. for Otto-2.5 hours,

it is not permitted to enter the isobutane-alkylation zone because it acquires a content of henzone. which; would compete with the isohutane for the ethylene. Consequently, when the reaction between ethylene and benzene. in the henzene-alkylction-zone'is completed, the reaction mixture is; passed: to. a. second settling system which is distinct and separate from the settling system following the isobutane-alkylatiori zone. The catalyst phase is recycled from the settling system to the benzene-alkylation zone or is removedfor purification and; recovery of aluminum chloride. The hydrocarbon phase is passed to a fractionationisystem for separatiorr'into various hydrocarbon f;ractions.'. Ethane. and V propane maybe recycledtothe cracking unit for formation r ethylene... Isobntane is re y l d to t e ethylene-recovery unit, for. use as absorbent for, ethylene. Motor-fuel hydrocarbons may be withdrawn as a single fraction, or they may be fractionated to recover specific hydrocarbons; for example, unreacted'benzenefmay be recovered as a separate fraction and may be recycled to the benzene-alkylation zone. Ordinarily, the ethylbenzene is obtained in this way as a separate fraction and is passed to further processing steps for ultimate utilization as styrene in the manufacture of synthetic rubber, but if desired it may be utilized together with the diisopropyl and other products of the process as a motor-fuel ingredient. A small proportion of products heavier than motor fuel is withdrawn as a tarry byproduct of the process.

It is to be understoodthat this invention should not be unnecessarily limited to the above discussion and description and that modifications and variations may be made-without departing substantially from the inventionor from the scope of the claims.

I claim:

1. An improved, parafiin alkylation process which comprisesreacting an alkylatable parafiin and an olefin in a first alkylation zone maintained under alkylation conditions in the presence of an alkylation catalyst; reacting a resulting reaction mixture effluent from said first alkylation zone with an alkylatable cyclic organic compound in asecond alkylation zone maintained under alkylation conditions; reacting a resulting reaction mixture efiluent from, said second alkylation zone with, an olefin in athird alkylation zone maintained under alkylation, conditions, and removing .from a. resulting, reaction efiiuent a hydrocarbon fraction boiling within the motor fuel boiling range as a product of the process.

2. An improved parafiin alkylation process which comprises reacting an isoparafiinwith an olefin in a first alkylation' zone maintained under alkylation conditions in the. presence of an alkylation catalyst producing an alkylate containing undesirablereaction lay-product compounds; contacting a resulting reaction mixture efiluent from said first alkylation zone with an easily alkylatable cyclic organic compound in amount stoichiometrically greater than the amount of said undesirable by-product compounds contained therein in a second reaction zone maintained under alkylation conditions such that. saidundesirable by-product compounds react. with a portion of said cyclic organic compound; reacting a resulting reaction mixture eflluent from said second alkylation zone with an olefin in amount stoichiometrically equivalent to the amount of unreacted cyclic organic compound contained therein in a third alkylation zone maintained under alkylationrconditions such thatsaid olefin reacts with unreacted cyclic organic compound, and removing from, a resulting reaction effluent a hydrocarbon fraction boiling within the motor fuel boiling range as a product of the D 3. The process ofjclaim 2 wherein said alkylation catalyst is anhydrous hydrofluoric acid.

4. The process of claim 2-wherein said alkylation. catalyst isfsulfuri'c acid.

5. The process of claim 2 wherein said alkylation catalyst is an aluminum chloride-hydrocarbon complex- 6. The process of claim 2. whereinvsaid easily alkylatable cyclic organic compound is benzene.

7. The process of claim 2 wherein said cyclic organic compound isfuran.

8. The process of claim 2 whereinv said isoparafiin is isobutane.

9. The process of claim 2 V wherein said. olefin is butene.

10. An alkylation process which comprises reacting isobutane with butenes in a first alkylation zone maintained under alkylation conditions in the presence of hydrofluoric acid as an alkylation catalyst to produce an'alkylate containing organic fluorine compounds; contacting a resulting reaction mixture comprising hydrocarbons and catalyst eflluent from said first alkylation zone with an alkylatable cyclic organic compound, in amount stoichiometrically in excess of the amount of organic fluorine compounds present in said efiluent, in a second alkylation zone maintained under alkylation conditions such that a portion of said cyclic organic compound reacts with said organic fluorine compounds; contacting a resulting reaction mixture comprising hydrocarbons and catalyst effluent from said second alkylation zone with an olefin in amount at least stoichiometrically equivalent to the amount of unreacted cyclic organic compound contained therein in a third alkylation zone maintained under alkylation conditions whereby said olefin reacts with said unreacted cyclic organic compound; passing a resulting reaction mixture eiiiuent from said third alkylation zone to a separation zone where it is separated into a hydrofluoric acid catalyst phase and hydrocarbon phase; recycling at least a portion of said catalyst phase to said first alkylation zone; passing said hydrocarbon phase to a fractionation zone and removing therefrom a hydrocarbon fraction boiling within the motor fuel boiling range as a product of the process.

11. An improved paraifin alkylation process which comprises reacting an isoparaifin with an olefin in a, first alkylation zone maintained under alkylation conditions in the presence of an alkylation catalyst producing an alkylate containing undesirable reaction by-product compounds; treating a resulting hydrocarbon phase from said first alkylatio-n zone with an easily alkylatable cyclic organic compound in an amount stoichiometrically in excess of the amount of the undesirable reaction by-product compounds contained in said alkylate containing hydrocarbon phase in a second alkylation zone maintained under alkylation conditions in the presence of a fluid alkylation catalyst such that a portion of said cyclic organic compound reacts with said undesirable by-product compounds; treating a reaction mixture efiiuent comprising hydrocarbcns and fluid catalyst from said second alkylation zone with an olefin in an amount stoichiometrically equivalent to the amount of unreacted I cyclic organic compound in a third alkylation zone maintained under alkylation conditions such that said unreacted cyclic compound reacts with said olefin; passing a resulting reaction mixture efliuent comprising hydrocarbons and catalyst from said third alkylation zone to a separation zone; separating said reaction mixture into a catalyst phase and a hydrocarbon phase; returning at least a portion of said catalyst phase from said separation zone to said second alkylation zone, and recovering from the resulting hydrocarbon phase a fraction boiling in the motor fuel boiling range as a product of the process.

12. An improved alkylation process for the production of diisopropyl which comprises reacting an isobutane-ethylene mixture in the presence of a halogen-containing fluid alkylation catalyst in a first alkylation zone producing an alkylate containing undesirable reaction byproduct compounds; treating a resulting alkylate-containing hydrocarbon phase with benzene in a second alkylation zone maintained under alkylation conditions in the presence of a halogen-containing alkylation catalyst such that the benzene reacts with said undesirable by-product compounds; passing a resulting reaction mixture efiiuent from said second alkylation zone together with an added olefin to a third alkylation zone maintained under alkylation conditions, and passing a resulting reaction mixture efiiuent from said third alkylation zone to a separation zone where it is allowed to separate into a catalyst phase and a hydrocarbon phase and separating from said hydrocarbon phase a fraction containing diisopropyl as a product of the process.

13. An improved paraffin alkylation process which comprises reacting an isoparafiin with an olefin in an alkylation zone maintained under alkylation conditions in the presence of a fluid alkylation catalyst producing an alkylate containing undesirable reaction by-product compounds; introducing said catalyst into said alkylation zone at multiple points intermediate the upper and lower portions of said alkylation zone; withdrawing from upper portion of said alkylation zone unreacted paraflinic and olefinic materials; treating a resulting reaction mixture comprising alkylate and catalyst with an alkylatable cyclic organic compound in amount stoichiometrically in excess of the amount of undesirable reaction by-products contained in said reaction mixture in a lower portion of said alkylation zone under conditions such that said cyclic organic compound reacts with said undesirable reaction by-product compounds; treating a resulting reaction mixture effluent comprising hydrocarbons and catalyst with an olefin in amount substantially stoichiometrically equavalent to the unreacted cyclic organic compound contained in said resulting reaction mixture efiluent; introducing a resulting reaction mixture comprising hydrocarbons and catalyst into a separation zone where said resulting reaction mixture is separated into a catalyst phase and a hydrocarbon phase, and withdrawing said hydrocarbon phase as a product of the process.

14. An improved paraflin reconstruction process which comprises contacting a paraffin in a first zone with a fluid parafiin reconstruction catalyst to produce a reconstructed parafiin and undesirable reaction by-product compounds, contacting a resulting reaction mixture eiiluent from said first zone with an easily alkylatable cyclic organic compound in amount stoichiometrically greater than the amount of said undesirable byproduct compounds contained therein in a second reaction zone maintained under alkylation conditions such that said undesirable icy-product compounds react with a portion of said cyclic organic compound; reacting a resulting reaction mixture efiluent from said second reaction zone with an olefin in amount stoichiometrically equivalent to the amount of unreacted cyclic organic compound contained therein in a third reaction zone maintained under alkylation conditions such that said olefin reacts with unreacted cyclic organic compound, and removing from a resulting reaction effluent a hydrocarbon fraction boiling within the motor fuel boiling range as a product of the process.

15. The process of claim 1 wherein the cyclic organic compound has at least two conjugated double bonds in the ring.

16. The process of claim 1 wherein the third 153-53 16??? alk lation' step' is eefiectewrwith ,a substantially REFERENGES CIT-EDWL- etmiene'free 018ml The following-references are-0f r'ecord in the" 17.' The process..-nf claim 16 wherein the ethylfil of -=-p 1-. cane-free olefin is propylene. s

lfiJTheprocess of claim 12 wherein the cat- 5 UNITmSTATESiPA'IENTS alyst in the first alkylation zone is an aluminum Number" N m D te chloride-hydrocarbon complex and. the zone is Mummy operated to give anrethylene conversion of 90- 54% and in which-pmcess ethyl benzene is re- 10 covered.

2,409,090" Wan-(meme: alt- Oct. 8, 1946 M ARY AN R MATUSZAK. 2,418,146 'r Uphamcr'. April, 1947 'D8CZT15, 1942' Chnicek 1 0015.17, 1944" Frey einuwfiun Mar. 27,1945" 2,432,482. IVISibHsZflk: Decfi9, 1947'

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