US2220090A

US2220090A - Conversion of hydrocarbon products

Info

Publication number: US2220090A
Application number: US176287A
Authority: US
Inventors: Bernard L Evering; George G Lamb
Original assignee: Standard Oil Co
Current assignee: Standard Oil Co
Priority date: 1937-11-24
Filing date: 1937-11-24
Publication date: 1940-11-05
Anticipated expiration: 1957-11-05

Description

2 Sheets-Sheet l B. l.. EVERING Er AL l CONVERSION 0F HYDROCARBCN PRODUCTS Filed Nov. 24, 1937 Nov. 5, lv 940.

Nov. 5, 1940. B. l.. EVERING ET AL CONVERSION 0F HYDRQCARBON PRODUCTS WMM ATTORNEY Filed Nov. 24. 1937 .Patented Nov. 5, 1940 PATENT ortica CONVERSION F HYDROCARBON PRODUCTS Bernard L. Ever-lng and George d. Lamb, chicago, lll., assignors to Standard Oil Company, Chicago, Ill., a corporation of Indiana 1 Application November 24, 1937, Serial No. 176,287

6 Claims.

This invention relates to the' preparation of a high antiknock motor fuel from an admixture oi isobutane and straight-run petroleum naphtha with the aid of catalysts. In particular, our invention relates to the preparation of a motor fuel product containing relatively large quantities of normally liquid branched-chain saturated hydrocarbons. Y

Saturated branched-chain hydrocarbons, and particularly mixtures of them, are very useful as motor fuels on accountI of their antiknock properl ties and high heating value. Also, the saturated branched-chain hydrocarbons have lower boiling points than the corresponding straight-chain paraftlns and, consequently, motor fuels containing substantial quantities of the former have better starting characteristics than'motor fuels containing large quantities of the latter. In addi- .0' tion, branched-chain paramn hydrocarbons, such as the iso-hydrocarbons, are very useful as starting materials in thelpreparation of many chemical products,

One of the principal objects of our invention is to react straight. run petroleum naphtha or saturated petroleum naphtha with isobutane prepared in situ to produce a motor fuel product of high antiknock value. Examples of the paraffinic straight run naphtha which may be used in our process are Mt. Pleasant naphtha, Pennsylvania naphtha, Mid-Continent naphtha and the like. This conversion of the admixture of hydrocarbons into normally liquid branched-chain saturated hydrocarbons is effected without substantial formation of fixed gases such as hydrogen and methane. Following the conversion of the hydrocarbons into a motor fuel product of high antiimock value, the products from the reaction zone may be fractionated by any of the methods o hereinafter described to give a motor fuel product4 of desired volatility and antiknock properties.

. Other objects, advantages and methods of utilizing our process will become apparent from the description hereinafter. The drawings, particularly Figure 1, attached to and lforming a part `of the specification arediagrammatlc illustrations of one arrangement of the apparatus which may be used in practicing our process; Figure 2 is a diagrammatic illustration of the types of reaction zones which may be used in our process.`

One embodiment of our process will be de-l scribed with reference Ato a petroleum' naphtha that has an l initial boiling point within'the range of 15G- 200 F. and an end boiling point rangingA (ci. '19e-9) from 360 to 420 F., however, our process may be used with petroleum naphthas that have initial boiling points above about F. and end boiling points within the range of 40G-500 F. The

straight run petroleum naphtha enters the sys- 5 tem through conduit A and is forced by pump Iii into the manifold i I. Isobutane enters.the system through line B and is forced by compressor I2 into the manifold il where it is mixed with .the other products therein. We prefer to use in our process the isobutane produced in the reaction zone of ourprocess and the isobutane so produced is introduced into line B through the recycled gas conduit 64. If desired, however, iso- 5 butane from an' extraneous source may be introduced into the sytem through lin'e D. A slurry or solution of aluminum chloride in light mineral oil isprepared in the catalyst mixer i3 and passed by pump I4 through line l5 to line I6 and zo then introduced into the manifold il. A promoter, or activator, namely hydrogen chloride, hydrogen bromide, carbon tetrachloride, the alkyl halides su'ch as methyl chloride or bromide, ethyl chlorideor bromide, propyl chloride or bromide, g5 butyl chloride or bromide, or any compound which in the presence of an aluminum halide yields a hydrogen halide is added to the manifold Il through conduit C with the aid of pump or compressor 29. Also, in the place of aluminum $0 chloride we may use other aluminum halides such as aluminum bromide. The naphtha, gas, catalyst and promoter are continuously fed to the system as above indicated and the admixture of materials is then passed through the elongated reaction zone or coil il, which is maintained at a temperature within the range of 15o-,600 F., but preferably within the range of4 ZOO-500 F. or 25o-475 F. At temperatures below about 475" F. substantially no fixed gases are produced dur o ing the conversion of the materials in zone il, however, at temperatures above 475 F. very small or negligible amounts of fixed gases may be formed. The pressure maintained in the coil A or reaction zone Il, may vary over a wide range. s that is, from atmospheric pressure to about 6000 pounds per square inch. In some cases the pressure may be even higher. We prefer to use a pressure within the range of about 20o-4000 50 pounds per square inch.v The time of contact employed in the reaction zone i1 `may vary considerably, ranging from about 1 to 150 minutes. When the naphtha in the reaction zone I1 is mostly in the liquid phase, we may use a reaction time of from 1 to,120 minutes, but preferably from 2 to 30 minutes. But when the naphtha is mostly inthe vapor phase, the reaction may be effected in a shorter period of. time, from 5 to 300 seconds. Of course, longer periods of time may be used if desired. Any suitable heating medium, such as steam, hot oil, or thermally stable liquids may be passed around the coil or heating zone I1 with the aid of conduits I8 and I9 to eiect the desired heating or reaction of the hydrocarbon components in zone I'I. Alternatively, the commercial type of pipe still may be` used as the heating zone. Also. mixing means may be used in the reaction zone to effect better contact between the naphtha and catalyst and halide promoter. Figure'2 shows three modied forms of the reaction zone wherein means are provided for thoroughly agitating or mixing the reactants. By keeping the materials in the reaction zone thoroughly mixed, the reaction time will be considerably reduced. l

As 'pointed out hereinafter, an aluminum halide-hydrocarbon complex, in the form of a solution, is formed in the reaction zone and it may be used as the catalyst in reaction zone I1. Alternatively, additional amounts of fresh aluminum halide may be added to this aluminum halide-hydrocarbon complex and the admixture used as the catalyst in the reaction zone. When 'aluminum chloride is used as the catalystthis does not react with the other constituents in reaction zone I'I is recovered by the fractionation and stabilization steps hereinafter described and returned to the reaction zone for further use. The converted products pass from the reaction zone through the transfer line 2li and valved conduit 2l and are introduced into ,the separator i22 where liquid phase separation is effected between the aluminium halide-hydrocarbon complex on thev one hand and the reacted and unreactcd products on the other. Alternatively, the products in the transfer line may be passed through the cooler 23before being introduced into the separator 22. The cooler is usually employed when the higher temperatures are used in the reactor Il. To assist further in the cooling of the products in the transfer line and thereby control the character' of the reaction, all or a part of the naphtha feed stock'may be used as a `quenching medium and introduced into the transfer `line through valved conduit 24. Also,

oils heavier than the feed stock may be used-v as the quenching medium. The quenching step may be used with or without the asistance of the Y cooler 23. f

pears to be some kind of a loose combination between the aluminum chloride and av product of the aluminum chloride-hydrocarbon reactions.

This solution is withdrawn from the bottom of the separator 22 through line 25 and passed by pump 26 through line 21 and check valve 28 to conduit I6 where it is returned to the reactor to serve as the catalyst for effecting the alteration oi saturated chain hydrocarbons into branchedchain parafns or iso-paraflins. When the aluminum chloride complex is recycled and used as the catalyst, hydrogen chloride or other hydrogen halides may be introduced into the system through line C and compressor 29 to serve as the promoter for this reaction. By recycling the aluminum chloride-hydrocarboncomplex andv adding small vor large amounts of hydrogen chloride, as above described, only small amounts of all or a part of the aluminum chloride-hydrocarbon complex may be withdrawn through valved conduit 30 and discarded or revivified and reused by introducing it into line I6. As another method of handling ,the aluminum chloridehydrocarbon complex withdrawn from the bot# tom of separator 22, lt may be passed through line 25, pump 26 and valved conduit 30a to the cata chloride are added thereto. This -admixture is then passed from 'the bottom of the catalyst mixer I3 and introduced into line I6 as hereinbefore described. If desired, small amounts of hydrogen halides such as hydrogen chloride and hydrogen bromide may be added to the catalyst in the catalyst mixer I3 by means of valved line I3a or introduced into the system through line C. In the operation of our process weprefer 'to add the promoter to the process through conduit C Ilyst mixer I3 where small amounts of aluminum s in pressure on the products before they enter the fractionator 34.

Fractionator 34 may be operated under vary-i ing conditions and it effects, as hereinafter indicated, the desired degree of fractionation. The temperature and pressure conditions, number of plates and reux ratio used in tower 34 may be varied to effect` the desired fractionation. The hydrocarbon products Awithdrawn from the top of fractionator 34 contain the unreacted isobutane and the motor fuel product containing large quantities of normallyliquid branched-chain saturated hydrocarbons. The overhead fraction from tower 34 is vpassed through line 36 to the cooler 36 and then introduced into the reflux drum 31. Of course, a substantial part of the hydrogen halide promoter will be in the overhead carbons.-

charged to the process has an initial boiling' point within the range of 260-350 F., the end a point to exclude hydrocarbons'bbiling above about 400 F., it is apparent that the bottom products from tower 34 will consist mostly of these heavy ends of the feed Vrxaphtha. Also, if

any such heavy hydrocarbon products are produced by the reaction in zone I1, they will also be withdrawn from the bottom of tower 34. A part or all of these hydrocarbon products in accumulator tank 39 may be recycled to the inlet side of the system and used as a part of the charging stock. The valved conduit 39a may be used to withdraw the hydrocarbon products from the accumulator tank.

The degree of fractionation effected in tower 3d will determine the end boiling point and, to av certain extent, the composition of the inal motor fuel product recovered from the bottom of tower or stabilizer 50. In one embodiment of our invention the overhead products from tower 34 may consist of unreacted isobutane and a fraction of hydrocarbons boiling within the gasoline range. For example, the overhead in tower 34 may consist of isobutane and a motor fuel product containing large quantities of normally liquid branched-chain hydrocarbons boiling up to about 380 to 420 F. Alternatively, the overhead from fractionator 34 may be cut to give a hydrocarbon product that does not exceed the rend point of the particular motor fuel product desired. In either of these modifications, the low boiling constituents, consisting almost entirely of isobutane, in the overhead from fractionator 34 are removed therefrom' in the stabilizer 50 tb give a high antiknock motor fuel product containing a `large portion of normally liquid branched-chain hydrocarbons. However, a portion of the isobutane may be left in the final motor fuel product as disclosed hereinafter.

If desired, the fractionator 34 may be operated so thatv theend boiling point of the overhead therefrom does .not overlap the initial boiling point of the feed naphtha to the extent indicated by the above examples. The end boiling point of the overhead from fractionator 34 may be cut ata point where the content of normally liquid straight-'chain paraiiins therein (excluding the gases, namely those boiling below 55 F.) will not exceed about 5 to 10% by volume.Y When the fractionator 34 is operated in this manner, the overhead therefrom Will contain a very high concentration of saturated branched-chain hydro- When operating fractionator` 34 according to this modification, the initial boiling point of the naphtha charged to the system should be at least as high as 200 F. and preferably within the range of 20G-320 F.

As another modification of the method for operating fractionator 34, the end boiling point of the overhead therefrom may be cut at a point below the initial boiling point of the feed naphtha. vFor example, if the feed naphtha boiling point of the overhead fraction from tower 34 may be cut at a point slightly below the initial boiling point of the particular naphtha charged to the system. In this modification of the process, the overhead from tower 34 consists almost entirely of branched-chain hydrocarbons.

Bubble trays 42 are placed in the tower 34 to assist in the fractionation. A portion of the heavy products in the bottom of tower 34 are withdrawn from trap-out plate 45, passed through line 46 to the reboiler 4l and then returned to the tower to supply heat for the fractionation of the products therein.

The liquefied products in the bottom of reflux drum .31 are recycled through linev 48 with the aid of pump 49 tothestop of bubble tower or fractionator 34 and used as reflux. The overhead from the reiiux drum is introduced into the stabilizer 50 where the desired fractionation is Vmade between the normally gaseous hydrocarbons, consisting almost entirely of isobutane on the one hand and the higher boiling products on the other. 'The fraction of normally gaseous hydrocarbonsv in tower 50 consists almost entirely,

of isobutane produced by the catalytic action oi the aluminum chloride and promotor or aluminum halide-hydrocarbon complex and promoter upon the feed naphtha in the reaction zone ill.

The product withdrawn from the bottom of sta 4 l bilizer 50 through valved conduit 5I contains converted naphtha which has a much higher antikno'ck value than the original ffeed naphtha. This increase in antiknock value is due, primarily, to the presence of branched-chain paraiins produced bythe interaction of the feed naphtha and isobutane in reactor I1. These branched-chain parafiins are branched-chain pentanes, branchedchain hexanes, branched .chain heptanes, branched-chain octanes and branched-chain paraiiins containing 9 or more carbon atoms in the molecule. From the foregoing description of our process, it is apparent that the product removed from the bottom of tower 50 through valved conduit 5I contains a very large amount of branched-chain saturated hydrocarbons, and, in addition, this fraction may be characterized as follows: (a) containing a substantial portion of the isobutane produced in the process and having an end boiling point below-or substantially equal to the end boiling point of the naphtha charged to the system; (b) containing a substantial portion of isobutane and having an end boiling `point commensurateA with commercial gasoline, that is, between 380 and 420 F.; (c) con- .taining substantially no isobutane and having an end boiling point below or substantially commensurate with the' end boiling point of the feed na'phtha; and (d) containing substantially no isobutane and having an end boiling point commensurate with that of commercial gasoline,

. that is, between 380 and 420"V F. 'I'he high antiknock motor fuel product withdrawn through conduit 5l may be used as a motor fuel as such or it may. be blended with other hydrocarbon fractions such as debutanized cracked gasoline.

polymerized gasoline or any motor fuel deficient 4 e I I 2,220,090

' 5. tics, and high heating value.

The unreacted isobutane passes from the top of the stabilizer through line 52 and may be passed through valved conduit 52a directly to the recycled gas line and returned to the reaction zone with the aid of compressor l2., In this modification of the process, cooling coils, not shown,

may be placed in the top of tower 50 to condense a part of the vapors therein for use as reflux.

This unreacted gas from the top of stabilizer 50 may be passed through line 52 to condenser 53 and thence info the reflux drum 54. Bubble trays 55 or other fractionating means are placed in stabilizer 50 to assist in the fractionation therein.

A portion of the product in the bottom of the stabilizer may be withdrawn from'the trap-out plate 56 and passed through line 51 to the re boiler or heating means 58 and then introduced into the bottom of the stabilizer. The heat added by the reboiler is usually sumcient to effect the desired fractionation in tower 50. It should be understood that other heating means may be used in the bottom of

towers

34 and 50 instead of, or in combination with, the herein described reboilers.

90 A portion of the liquefied hydrocarbon product in reflux drum 54 is withdrawn through line 59 'and passed by pump 90 'through valved conduit 6I to the top of the stabilizer for use as reflux. Ofcourse, a cooling coil may be used in the'top a5 oftower 50 along with the use of this reflux.

The remaining portion of this liquefied hydrocarbon product in line 59 may be passed through valved conduit 62 and introduced into the manifold Il for further use in the process of conV I o verting straight-chain parafhns into branchedchain paraillns. By employing an elcient cooler at 53 substantially all ofthe products `in reflux drum 54 will be in the liquid phase and the portion thereof that' is not used as reflux may be recycled through line 62 to the reactor llthereby avoiding the Anecessity of compressing the gases that are removed from the overhead of drum 54. As previously stated, the hydrogen halide promoter which isemployed in the re` 'action zone l1 will pass along with the overhead from

towers

34 and 50 and consequently a substantial portion of this promoter will be present in the products 4recycled from drum 54 to the reactor I1. If desired, the draw-off line 63 may 55 be used to withdraw from the system a portion of the liquefied hydrocarbon product in line 59.

The uncondensed gases in reflux drum 54, assuming that all of the products in drum 54 are not recycled in the liquid phase, is recycled to the inlet side of the system through valved conduit 64 or the recycled gas line. If desired, all of the hydrocarbons withdrawn from the top of reflux drum 54 may be passed through valved conduit 55 and introduced into the absorber 56 where the 65 hydrogen halide such as hydrogen chloride is separated from these gases. Water, hydrochloric acid orv any other suitable solvent may be introduced into the top of the absorber throughv line 61v and withdrawn through the bottom thereof through line 68 with the dissolved promoter. The thus washed gases vmay be returned tothe recycled gas,

line 64 through valved conduit-69 and from time to time a small portion of these gases may be vented through valved conduit 10 in order to prevent inert gases from building 'up in the system.

By removing the halide promoter and any free halogen that may bepresent in these gases, corrosion of the compressor l2 may be considerably minimized. y g

It is apparent, therefore, that in the operation 5 of our process only the liquefied fraction of hydrocarbons, consisting almost entirely of isobutane withdrawn from the bottom of reflux drum .54, may be recycled through line 62 to the reaction zone, Alternatively, or in combination with l0 this step, a portion of or all of the liquefied fraction and all pr a substantial part of the gases removed from the top or reflux drum 54 may be recycled to the reaction zone. It is apparent, there-I fore, that the isobutane may be recycled in the 15 liquid or gaseous phase.

As another modification of our process, the hydrocarbon components introduced into the reactor Il may consist almost entirely of isobutane and rstraight run petroleum naphtha having an 20 initial boiling point of about 260270 F. When these materials are reacted with the aid of aluminum chloride or the aluminum halide-hydrocarbon complexes while in the presence of a promoter such as hydrogen chloride, hydrogen bromide, car.- .25 bon tetrachloride and the like, the fractionators 3@ and 50 may be operatedto give a product in line 5| which `boils below 260270 F. and which consists predominantly of branched-chain hydrocarbons containing from 4 to 8 carbon atoms each 30 in the molecule. In this case the stabilizer 50 may be operated so that only the branched-chain hydrocarbons containing from 5 to 8 carbon atoms are withdrawn from the bottom thereof through line 5i and the isobutane 'recycled by any of the 3i methods hereinbefore described.

The temperature employed in the tops and botI toms of

towers

36 and 50 as well as the pressures maintained therein may be varied in order to effect the desired fractionation. When tower 34 is op- 40 erated at a pressure of about 210 pounds per square inch, a top temperature of about 440 F. and a bottom temperature of about 600 F., the products withdrawn from the bottom thereof through. line 38 will consist mostly of hydrocarbons boiling 45 above about 4l0-430 F. whereas the products taken overhead from tower 34 will consist mostly of lower molecular weight hydrocarbons. When tower 50 is operated at a pressure of about 200 pounds per square inch, a top temperature of 50 about 200 F. and a bottom temperature of about 500 F., the products withdrawn through line 5l willbe substantially free from isobutane, however, if tower 50 is operated at a pressure of about l 200 pounds per square inch, a top temperature 55 of about F. and a bottom temperature of about 400 F., a substantial portion of the isobutane produced in the process will be retained in the product withdrawn from the bottom of the tower. y l 60 In carrying out our herein described process, the proportions of products charged to the reaction zone I1 may vary somewhat. For example, for one part by weight of naphtha charged to the reaction zone, the parts by weight'of isobutane, 65 catalyst and promoter may be from 0.1 to 1; 0.01 to 1 and 0.03 to 0.3 respectively.

In any of the modifications hereinbefore set forth, we may withdraw a part of the oil from accumulator tank 39 through valved conduit 39a in- 70 stead of recycling it to the reaction zone. Alternatively, a. once-throughoperation may be used wherein the heavy products in the accumulator tank 39 are not recycled, However, in this oncethrough conversion of the naphtha we do recycle 75 the isobutane by one of the methods hereinbefore described. 4

As stated hereinbefore, Figure 2 shows some of the modiiled forms of the reaction zone which may be used to efect intimate liquid phase ccntact as well as vapor phase contact between the hydrocarbon reactants and catalysts. In describing the three modiiications of the reaction zone, the same numerals will be used,` whenever possible, as are used on Figure 1.

Modification A illustrates the use of a mixer mounted within the reaction zone I1. This modication is used preferably for liquid phase oper` ations. The feed naphtha'isobutane, catalyst and promoter enter the reactor i1 through the manifold I I and pass into the reactor through line I Ia. If desired, a part or all of the catalyst and/or promoter may, be added to the reactor through line lib. As the hydrocarbon, catalyst and promoter pass up through the reactor, they are thoroughly mixed by the revolving blades 1I which are mounted on the shaft driven by the motor 12. A packing is placed around the shaft at 13 to prevent the escape of gases and liquids from the reaction zone. A closed steam coil 15 is placed inside the reactor to provide the necessary heat for the reaction, however, the products in line II may be heated by any conventional means before entering the reactor I'. The converted products pass from the reaction zone through the transfer line 2t, valved conduit 2i and are introduced into the separator 22 where liquid phase separation is effected between the aluminum halide-hydrocarbon complex on the one hand and the reacted and unreacted products on the other. Alternatively, the products in the `transfer line may be passed to the cooler 23 before being introduced into the separator 22. The feedstock may be lntroduced through valved conduit 24. The aluminum halide-hydrocarbon complex is withdrawn from the lower part of the separator 22 and passed by line 25, pump 25,1ine 21 and check valve 28 to the inlet of the reaction zone. Intermittently or continuously all or a part of the aluminum halide-hydrocarbon complex may be withdrawn through valved conduit 3l) and treated as hereinbefore described. 'The reacted and unreacted hydrocarbon products in separator 22 which are above the liquid level of the complex as shown by line 3i are withdrawn through line 32 with the assistance of pressure regulator 33 and introduced into the fractionator 34. In brief, this modification of the reaction zone is very easily adapted to the'process herelnbefore described with reference action zone through line 20 and are introduced into separator 15 where the unreacted isobutane is withdrawn from the top thereof through valved conduit 16 and returned with the aid of the compressor 11 to the bottom of the reactor I1. 'I'his step of recycling the unreacted gas in combination with the turbo-mixer provides an excellent way of obtaining thorough contact between the gases and promoter on the one hand and the liq- .uid feed naphtha and aluminum chloride catalyst on the other. 'I'he liquid products in the bottom of separator 15, including the aluminum halide-hydrocarbon complex as well as liquid hydrocarbons, are withdrawn from the bottom thereof through line 18 and introduced into the separator 22. The separation effected in separator 22 and the method of handling the aluminum halide-hydrocarbon complex and hydrocarbon products are the same as described with reference to modication A and also Figure 1. To prevent the building up of unreacted hydrocarbons within reaction done I1, a valved by-pass 16a is provided for venting some of the gas in separator 15 into conduit 32 so that they will pass into 'the fractionating system as described in Figure l.

In place of the mixing device shown in the above two modifications, we may use a turbo-- mixer.

Modification B illustrates the use of a vapor phase reaction chamber. 'Ihe feed naphtha, isobutane, and promoter enter the reactor I1 through the manifold II and pass into the reactor through line `I la. If desired, a part or all of the promoter may be added to the reactor through line I Ib. The products in line IIa are sprayed or atomized into the bottom of the reaction zone il. We prefer to heat the hydrocarbons in manifold II before they enter zone I1 so that they will vaporize when introduced therein. A closed steam coil 'it is provided in the chamber to maintain the desired temperature therein. The catalyst comprising a mineral oil slurry of the aluminum halide is sprayed into the top of the chamber i1 thru conduit I. This slurry of catalyst may be prepared in the mixer as shown by Figure l. The counter current contact between the descending catalyst and ascending hydrocarbon vapors and promoter insures intimate contact between the products in the reaction zone I1, -The aluminum halide-hydrocarbon complex falls to the bottom of the chamber Il and is withdrawn thru line 1Q.' If desired, the liquid level of the aluminum halidehydrocarbon complex or catalyst solution in zone I1 may be permitted to rise a short distance above the level of the nozzle on line I Ia so that the feed products in line I I will be atomized into the liquid catalyst or catalyst slurry. 'Ihis complex or liquid catalyst may be recycled directly to line- I5 or it may be mixed with additional quantities of the aluminum halide and/or promoter and re turned to line I E. 'I'he reacted and unreacted hydrocarbon constituents in zone I1 are withdrawn from the top thereof through line with the assistance of the pressure-reducing valve 82 and introduced into the fractionator 34 as shown in Figure' 1.

The pressure and temperature conditions maintained in modications A, B and C of the reaction zone may be the same as those described in connection with Figure 1. Also, it has already been pointed out that the time of contact may vary over a relatively wide range and that thorough mixing or agitation of the constituents in the reaction zone I1 materially shortens this` time of contact.

While we have described our invention with reference to specific examples by way of illustration, it is apparent that other modilcations may be employed.

We claim:

l. In a process for converting substantial amounts` of the straight-chain paramn hydrocarbons vin a low antiknock straight run petroleum naphtha into saturated branched-chain hydrocarbons whereby a motor fuel fraction having a relatively high antiknock value is obtained, the steps comprising contacting in a reaction zone an admixture of said petroleum naphtha, isobutane, a conversion catalyst selected from the bromide and their-hydrocarbon complexes, and

a halogen-containing promoter for said catalyst,V

the reacting hydrocarbon gases present -being largely isobutane and substantially. free, of unsaturated hydrocarbons, at an elevated temperature andpressure suflicient to convert a substantial part' o1' the straight-.chain paraiiin hydrocarbons in said petroleum naphtha into saturated branched-chain hydrocarbons without substantial formation of hydrogen and methane, withdrawingthe products from said reaction zone and separating said motor fuel fraction from said products.

2. In a process for converting substantial amounts of the straight-chain paraflin hydrocarbons in a low antiknock straight run petroleum naphtha into saturated branch-chain hydrocarbons whereby a motor fuelfraction having a relatively high antiknock value is obtained, the steps comprising contacting in a reaction zone an adxnixture of said petroleum naphtha, isobutane, aluminum chloride and a hydrogon halide, the

reacting hydrocarbon gases present being largely isobutane and substantially free of unsaturated hydrocarbons, at a temperature within the range from. about 150 F. to about 600 F. and under superatmospheric pressure, whereby substantially no hydrogen and methane are formed, withdrawing the products from said reaction zone and separating said motor fuel fraction from said products.

3. The process of claim 2 wherein said temperature is in the rangegfrom about 200 F. to

about 500 F. and said pressure is in the range from about 200 to about '4000 pounds' per square inch.

4. In a continuous process for converting substantial amounts of the straight-chain paraffin hydrocarbons in a low antiknock straight run petroleum naphtha into saturated branchedchain hydrocarbons whereby a motor fuel i'racsubstantial formation of hydrogen and meth-v ane, withdrawing the products from said reaction zone and separating therefrom an aluminum halide-hydrocarbon complex, fractionating the remaining hydrocarbon productsto produce said motor fuel tractionand a gaseous fraction con: sisting largely of isobutane and substantially free of unsaturated hydrocarbons. and recycling at least a portion of said gaseous fraction to said reaction zone. l V o 5. 'In a continuous process for .converting substantial'amounts of the straight-chain paraiiln hydrocarbons in a'low antiknock straight run petroleum naphtha into saturated branched-chain hydrocarbons whereby a motor fuel fraction having a relatively high antiknock value is obtained, the steps comprising contacting in a'. reaction zonean admixtune of said petroleum naphtha, isobutane, aluminum chloride and a hydrogen halide, the reacting hydrocarbon gases present being largely isobutane and substantially free of unsaturated hydrocarbons, at s. temperature within fthe range from about 150 F. to about 600 by substantially no hydrogen and methane are f formed, withdrawing the products from said reaction zone and separating therefrom an aluminum chloride-hydrocarbon complex, fractionating the remaining hydrocarbon products to produce said motor iuel fraction and a gaseous fraction consisting largely of isobutane and substantially free of unsaturated hydrocarbons, and recycling at least a portion of said gaseous fraction to said reaction zone.

. 6. In a process for converting substantial amounts of the straight-chain paraflin hydrocarbons in a low antiknock straight run petroleum naphtha into saturated branched-chain hydrocarbons whereby a motor fuel fraction having a relatively high antiknock value is obtained, the

steps comprising contacting in a reaction zone an admiature 0f said petroleum naphtha, isobutane, aluminum chloride and' a hydrogen halide, the reacting hydrocarbon gases present being largely isobutane and substantially free of unsaturated hydrooarbons, at a temperature within the range from about 200 F. to about 500 F. and under a pressure in the range from about 200 to about 4000 pounds per square inch, whereby substantially no hydrogen and'methane are formed, withdrawing the products from said reaction zone and separating therefrom an aluminum chloride-hydrocarbon complex, subjecting the remaining hydrocarbon products to stabilization, whereby substantially all of the isobutane is removed from said hydrocarbon products, and said motor fuel fraction and a gaseous fraction consisting largely of isobutane and substantially free BERNARD L. EVERJNG. GEORGE G. LAMB