Sept. 10, 1946. c. s. LYNCH ETAL 2,407,311 CHEMICAL PROCESS Filed March 6, 1943 v CATA I_VST .DRA W of?? ' _ ' _lo Rem/egg Pra/VP. 2,407,3111 ¿UNITED STATES PATENT OFFICE Patented'sept. 10, 1946 CHEMICAL PROCESS Charles S. Lynch, Plainfield, and Howard G. Codet, Mountainsìde, N. J .„ assignors to Stand ard Oil Development Company, a corporation of Delaware Application March 6, 1943, Serial No. 478,184 9 Claims. (Cl. .E60-683.4)4 2 1 The present invention relates to improvements in the art of. producing aviation gasoline and, Referring to the drawing, I is a reactor, Car rying a pressure gauge 20, preferably consisting more particularly, it relates to a method of pro of a cylindrical shell or case, packed With a suit such that, when it is'leaded with 4 cc. of lead from the system. However, during the early phases of the operation all of the AlCls which able packing material such as Raschig rings R, ducing 2,3 dimethyibutane by aikylanng emmene f and 5 is a settling zone into which reaction prod with isobutane. In the application of Ralph M. Hill and Charles l-I. Watkins, Serial No. 472,192, ' ucts pass from the top-of the reactor. In the .settler 5, entrained catalyst material, i. e. the filed January 13, 1943, there is described a meth AlCl; hydrocarbon complex collects at the bot od of alkylating ethylene with a catalyst compris tom and may be withdrawn thro-ugh line 2I. Of ing an aluminum chloride-hydrocarbon complex to yield 2,3 dimethylbutane, a substance which>` 10 course, other portions of the AlCls complex which venter 5 may gravitate back into I. But 2| pro when used as a fuel in an internal combustion engine, has a rich mixture performance rating ' vides a method of withdrawing spent catalyst tetraethyl per gallon, itis superior to pure iso octane plus 6 cc. of leadtetraethyl per gallon. . In 15 enters Zone 5> gravitates or drains back into re action zone _I and itis only after the process is theçaforesaid application, all of the aluminum chloride was addedr at >the begnning of there oil-stream fora relatively long period .of time >( 100 hours >ormore) that Spent catalyst is With drawn through line' 2 I, in the ordinaryfmethod of operating; However, v.if the tower should become ñlled with catalyst and then flowed into Zone 5 (thuseontaminating the productstream I5) be fore the time period stated, obviously the valve in action and after an induction period, the catalyst ' vcomprising the said aluminum' chloride-hydro carbon complex was formed whereupon the' octane number of the ICs fraction greatly im proved. However, this induction period required forty hours before the octane number of the Ce fraction (containing the 2,3 dimethylbutane) kat tained an octane number ciA over 90 as deter mined bythe A. S. T. M. method. ' . line 2I'shou1d‘be opened to draw oiT catalyst. 25 The product is withdrawn through line I0 and a portion of this material containing in addition to the desired 2,3 dimethylbutane, unreacted iso butane is ‘recycled Via line II and pump' I2 to re v We have now discovered a method forirnprov ing the operation described in the saidapplica- ' tion of Ralph- M. -Hill and Charles Watkins, , actor I. The remainder of the product is con and in its essence our invention involves'supply 30 V'ducted through’line I5 to distillation, washing and purificationvequipment adapted to yield a ing fresh aluminum chloride to the'> circulating pure product; " The isobutane yremoved from the stream of reactants and recycled product inin product during finishingis ‘recycled to the reactor crernental portions rather ythan adding the total Ithruî the hydrocarbonfeed‘line 2 for further use quantity at thebeginning. By thus proceeding, inv the process. The method of zpurifying the we greatly reduce the' induction vperiod requiredl Lproduct is omitted for purposes of simplicity of to form the'catalytically active _aluminum ehlof. ride-hydrocarbon complex. It is pointed out " ' `explanation and because the invention resides in other features of our process. that as in the process described in the aforesaid The recycled material in line I I may be passed application of I-Iill et al.,'the catalyst isv formed' by the interaction between isoparaflinic, oleñnic 40 via pipe I‘I through fresh AlCla container I8 and thence through rpipes I9 and `22 into .the reactor. hydrocarbons and AlCls.v Meanwhile,` fresh feed containing ethylenev and An object of our invention‘therefore is to alkyl- ’ isobutaneis dischargedintorhe reactor I through ate mono-oleñns7 particularly ethylene or propy1 pipe 2. The ratio of isobutane to ethylene -in the ene, with isoparaiiins such as isobutane, and the`Á ` fresh feedmay be'relatively low, say .4 mols of like in the presence of ya catalytically active alu- ’ isobutane tov 3 of ethylene. However, by employ- , minum . chloride-hydrocarbon complex under ' ing a high'recycle ratio, say from l0 to'lGD v01. conditions such that the induction period neces -umes >of liquid inr recycle line II to one volume of 'liquid feed in line và, a high internal ratiol of iso to olefin is maintained in reactor I. This promotes the _formation of an alkylateof desired 50 ‘butane internal ratio Aof isoparaflin to oleiinmayarnount high quality, isgreatly reduced. . - ‘ sary for the formation of a catalytically active; raluminum chloride-hydrocarbon complex, whichv ` :fromj 10 to 100 or more mols of isoparaiiinper Another object of ourinvention‘is to ,scoper mol of olefin. ate the .alkylationfof ethylene with isobutane as " -to enable the process to functíonf'continuously. ' Other and further objects of our invention Will appear from the following more detailed descrip n 'We consider the crux of our invention to reside , DI in the manner of operating the process with re spect to the addition of AlCla from a reservoir I8.l »We 'start :the‘operation ‘by first -filling-,the reactor with `liquid isobutane, satura-ting the isobutane I1n the accompanying »drawing we have .shown a Ewith¿ethylene at the operating pressure, and then Vflow plan illustratingapreferred modi-flcationvof 60 feeding i-sobutanè -and ¿ethylene from '2 into the' our invention.. . ’ .» tion'and claims. ' l > , ' y . 2,407,311 3 4 reactor I. >During the iirst phase of the opera tions nearly all of the material recovered from the top of the reactor is recycled by way of pipes- ber, namely an octane number of 94 as deter mined by the A. S. T. M. (American Society for Testing Materials) some time between the 5th II, IT, reservoir IS and pipes I9 and 22 to the re actor I. In. passing thro-ugh the reservoir I8 fresh A1Cl3 is absorbed or acquired by the ñowing ' and 8th hour so that from at least the 8th hour until the end of the operation the octane number r. of the Cs fraction was considerably above 90. We set forth below the result of a second run stream of reactants. After that, the recycle stream passes into the reactor and after about 8 which we made, including operating conditions and an inspection of the product. In this run, hours of thus operating a product having an oc tane number above 90 A. S. T. M. is removed all of the AlCla was added at the start of the op eration, and it will be noted that the product dis continuously from line vI5 for puriñcation. Further describing our method of operating the tribution as well as the yields were low due to excessive cracking, no doubt, as evidenced by the system, we» have proceeded as follows: 1.8 lbs. of aluminum chloride was placed in the large amounts of low molecular Weight hydro receptacle I8 in four aliquot portions of 0.45 lb. each during the first eight hours of operation. carbons. Also the octane number was low up to 21-24 hours. Table II.--Ethylene alkylation 2.5 lbs. AlCla charged tower at start. Promoter: ethyl chlo ride. ' Pressure: 275 lbs. sq. in. Temp.: 105-110° F. ? n Feed: 27 mole C2H4/hr.; iso C4/C2=mol ratio 3/1 (in fresh feed). Hours of operation ____________ __ 5-8 270 260 272 256 245 140 ___ __ 40 39 31 46 34 43 24 52 14 62 11 64 8 64 5 52 __ 16 17 16 17 18 18 20 26 265° F.-|-(Cu-l-) ____________ __ 5 6 7 7 6 7 8 17 Ca _____________________________ __ 85. 7 85.6 89. 1 91. 9 92. 5 93.6 _____ Net percent alk. on Cz _. 269 -F. (C5)_ 11G-165° F. (Cs) ____ __ 165-265o F. (C1-CSL--- ASTM o 129 No.: C11-Cs _________________________ __ 0.45 lb. of aluminum chloride was placed in re ceptacle I8 and the recycle stock passed through the receptacle containing the aluminum chloride. This was continued for a period of two hours, whereupon a second 0.45 lb. portion of aluminum chloride was added to receptacle I8. This proce dure was repeated at the sixth and eighth hours until all of the 1.8 lbs. of aluminum chloride was 85. 6 73.8 _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ ._ product and the yield. To recapitulate, our present invention relates to a continuous method of alkylating ethylene with isobutane to form substantial quantities of 2,3 No» more aluminum chloride was added after _that until at the 54th hour whereupon an other 0.22 lb. of aluminum chloride was added to receptacle IS. The addition of aluminum chlo 69.8 We wish to point out that best results are ob tained by maintaining a high recycle ratio. That is to say from 10 to 100 volumes of the product is recycled via line I0 and pump I2 to the reactor per volume of fresh feed (ethylene plus isobu tane), in line 2. The purpose of this high recycle ratio is to maintain a high ratio of isoparaiiin to oleñn in the reactor for it has been foundthat this high ratio improves both the quality of the In other words, at the beginning of the operation added. 13-16 21 -24 29-32 37>40 45-48 53-56 65~68 ¿lo dimethybutane which is a very valuable blending agent in the manufacture of aviation fuels. We have found it advantageous to add the catalyst to the system in incremental portions rather ride continued at the 66th, '78th,‘90th, 102nd, and 114th hours until a total of 3.1 lbs. of aluminum chloride had been added. A temperature of 105° F. and a pressure of 275 lbs. per square inch gauge was maintained within the reactor. than to add the catalyst at o-ne time for we re duce the number of hours necessary for the cata ~ As a result of the ope-ration, we set forth be lyst to attain maximum activity. In other words, where the catalyst is formed in situ by interaction low thedata obtained as a result of the continu ous run: Table I.--Ethylene'z'sobutane aZlcyZatz'onf--contínuous tower Catalyst: A1013 (l). Promoter: C1HßOl(2)/. / Mol ratio: liso C4/C2=3.0 (in fresh feed). Pressure: 2751bs./sq. in. Hours of operation.. __ 5-8 9-12 17-20 29-32 33-36 41-44 49-52 57-60 _- 105 106 104 100 10 10 7.5 7.5 187 208 222 sumed (cumulative)___' _________________ __ 197 220 242 262 4.12 6. 76 2. 3 3. 8 3 66 23 8 4 67 21 8 2 71 20 7 ____ 94. 5 C2H4mols/hr,.»__-______ __ 98 7. 5 94 7. 5 90 7. 5 101 7. 5 230 227 221 219 263 7. 59 4.2 265 8. 98 5.0 61-64 73-76 81-84 93-96 105-108 117-120 105 104 -108 108 107 108 7. 5 7. 5 7. 5 7. 0 7. 0 7. 0 Wt. per cent (J5-talk. on 02H4 fed (cumu lativ _________________________________ __ 220 223 224 229 230 233 282 14. 6 6.4 280 16. 1 6.6 282 18. 5 6.8 280 20. 8 7.1 280 23. 2 7.4 61 Wt. per cent CVI-slk. on 02H4 fed c011 Yield gal. alk. (cumulative) ____________ __1 54 . Yield gal. alk/lb. A1013 (cum Vol. per cent alk.: 3 70 3 Y 70 10 60 2 61 21 2O 22 28 6 Y 7 8 9 14 18 7 1l 65 ` 14 62 18 18 6 6 ASTM oct. No _____________________ _.Í ss. 2 1 Iso C4=isobutane It isobvious from the above data that the frac tion of the product which is the most important fraction, namely the C6 fraction or that fraction boiling from 11G-165° F., had a high octaneV num 75 between the aluminum chloride and hydrocarbon, as is the case in the present process, we have found that there is an induction period during which the alkylate` formed, particularly the Cs 2,407,311' 3. 'I‘he method set forth in claim 1 in which a ratio of at least 100 mols of isoparafûn per mol of olefin is maintained in the reaction zone. 4. A continuous method for alkylating ethylene fraction, is of inferior quality particularly as re gards octane rating. We have found that we may reduce the induction period very substan tially by adding the catalyst in incremental por tions rather than by adding to the system all of the catalyst intended to be used in one _total >with isobutane which comprises mixing ethylene with isobutane in a reaction zone containing an inert contact material, withdrawing a mixture of quantity. it is obvious that two or more receptacles I8 unreacted ethylene and isobutane from said re action zone, recycling the mixture through a that is to say, while one of the receptacles I8 is » of the process for an induction period suiñciently In order to operate our process continuously, should be provided and these may be operated in lO catalyst charging zone containing AlCls and thence to a reaction zone, maintaining the cir parallel so that the hydrocarbon recycle in line culatory system indicated during the early phases I I may be alternately fed through the receptacles, being recharged with catalyst, the other may be on the onstream operation thus maintaining co-n tinuity of operation. long to permit the formation of AlCla hydrocar 15 bon complex by interreaction of said AlCla and ’ As to operating conditions in the reaction zone said hydrocarbons, simultaneously feeding iso butane and ethylene to said reaction, during said induction period, withdrawing a portion of the the temperature may vary froml 90° to 175° F. with ' stream leaving the reaction zone as product fol 100° to 110° F. preferred, the pressure may vary from 100 to 1000 lbs. per square inch gauge with 20 lowing the induction period, recycling the re mainder of the said stream through the catalyst 200 to 400 lbs. preferred, and we use from 0.04 charging zone to the reaction zone, and periodi lb. to 0.08 lb. of AlCla per gallon of alkylate pro cally adding fresh AlCl3 to said catalyst charging duced in the system. zone. By an analogous method we may alkylate ethyl 5. The method of claim 4 in which the volume ene, propylene, butylene and other mono-oleñns 25 ratio of recycled stream to total volume of fresh with isobutane or some other isopar‘anin such as feed isobutane and oleñn is from 10 to 100 to 1. isopentane. ‘ 6. The method of claim 4 in which the induc Many modifications of our invention will read tion period is from 5 to 8 hours. ily suggest themselves to those> who are familiar 7. The method specified in claim 4 in whicha 30 with this art. > temperature of from 100° to 110° F. is maintained What we claim is: ' in the reaction zone. 1. In the process of continuously alkylating 8. The method speciñed in claim 4 in which the ethylene with an isoparafiin, the improvement _reaction is carried out at temperatures within the which comprises forcing a mixture containing isoparañin and ethylene through a catalyst charg-V ing zone containing aluminum'chloride and which can be recharged therewith from time to time whereupon a portion of said aluminum chloride is absorbed in the said mixture, forcing the mix ture containing the aluminum chloride into a 40 reaction zone, permitting the ethylene, isoparaiiin and aluminum chloride to remainrin contact with each other for a suñicient period of time to form a catalytically active aluminum Vchloride-hydro carbon complex, thereafter” continuing 'the flow of isoparaii'in and ethylene through the catalyst charging zone and through the reaction Zone, range of from 90-175° F. 9. VIn the continuous alkylation of ethylene with isobutane, the improve-ment which comprises pro- ~ Viding `a body of AlCls in a catalyst charging zone, feeding isobutane and ethylene to a reaction Zone, withdrawing a recycle stream containing unreacted ethyleneand isobutane- from said re action zone, flowing said recycle stream through said body of AlClaA in the» catalyst charging zone to said reaction zone for a period of 5 to 8 hours until the reaction product shows an octane num ber above 90, then withdrawing the reaction prod uct, and adding A1013 in aliquot proportions from time to time by directing the recycle stream maintaining the reaction zone at elevated tem through the catalyst charging Zone and thereby peratures and pressures during the process and 50 maintaining the octane numbervof the product A vwithdrawing from the reaction zone a product continuously above 90. ¿ containing a Ce fraction of high octane number. 2. The method set forth in claim 1 in which fresh aluminum chloride is added to the catalyst charging zone at spaced intervals of time. 55 CHARLES S. LYNCH. HOWARD G. GODET.