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„Ey-23194@ -4 Y H. c. MAYLAND ALKYLATIQN ’ 2,494,393 OF PARAFFIN HYDROCARBONS Filed July 24“, 1942 v FRESH 2 Sheets-Sheet 1 FR / July 23, 194e. H. c. M_AYLAND ' 2,404,393 ALKYLATION OF PARAFFIN HYDROCARBONS Filed July 24, 1942 2 Sheets-Sheet 2 œ 0 @.N@ _o @ai Patented July 23, 1946 2,404,393 l UNITED STATES PATENT oFFlcE ' 2,404,393 ALKYLATION OF PARAFFIN HYDROCARBONS Harrison C. Mayland, Chicago, Ill., assignor to Universal Oil Products Company, Chicago, Ill., a corporation of Delaware Application July 24, 1942, Serial No. 452,122 6 Claims. l (Cl. 26g-683.4) 1 2 When hydrogen fluoride catalysts are used to effect alkylation, certain organic materials are formed in addition to the alkylation products 0f the reaction which tend- to accumulate in the catalyst phase and which serve effectively as 'or ganic diluents for the catalyst. The nature of- This invention relates to the alkylation of hy drocarbons in the presence of a hydrogen ñuoride catalyst. It is more particularly concerned with an im- ‘ proved process for the production of higher mo lecular weight isoparañins by the alkylation of the organic diluent formed in the alkylation re lower boiling isoparaflins with oleflns in the pres action is not known clearly, but it is believed that in some cases at least higher molecular Weight ence of a hydrogen fluoride catalyst wherein the concentration of hydrogen fluoride is controlled within a preferred range in order to obtain the 10 alkyl fluorides, particularly those having 6 or more carbon atoms per molecule, are present as well as ' optimum product quality. highermolecular weight -polymers and organic The production of higher molecular weight iso fluorine-containing complexes. parafdns having valuable anti-knock properties of considerable importance in the refining in dustry. A convenient source of such hydrocar bons is the catalytic alkylation of low boiling iso paraii'ins such as isobutane and isopentane with normally gaseous olefins such as propylene and the butylenes. Large quantities of these hydro carbons are available from the cracking of pe troleum oils and from the natural gasoline in dustry. The alkylation of isoparaflins utilizing a liquid l y As the alkylation reaction is conducted ccn and therefore suitable for use in aviation fuels is 16 tinuously with recycling of the separatedused catalyst, a substantial portion of the organic diluent formed remains dissolved or dispersed in the catalyst phase and is therefore continu ously recycled within the system. It is thus pos 20 sible for the organic diluent content of thecat alyst to build up with continued use and theeffective hydrogen fluoride concentration is there- . by reduced. Myinvention contemplates controlling the ac. catalyst, such as hydrogen fluoride, is ordinarily 25 cumulation of organic diluent in the’catalyst> conducted by introducing the hydrocarbon charg ing stock and catalyst into a mechanically agi tated reaction Zone or any reaction zone suitable phase by any convenient method of control whereby to vcontain the effective hydrogenfluo ride concentration within the most desirable for effecting intimate contact between the hydro 30 range as hereinafter described. One method of carbons and catalyst. The hydrocarbon-catalyst controlling the accumulation ofv organic diluent mixture is maintained at the desired tempera comprises withdrawing a portion of the used cat ture, pressure, and time of contact, and it is pref alyst from the system and replacing itwith rela erable that a substantial molecular excess of tively uncontaminated catalyst such as fresh hy isoparaffins over olefins be maintained through drogen fluoride or regenerated catalyst having 35 out the entire reaction. The reaction mixture is a higher effective concentration of hydrogen fluo- , withdrawn and is introduced into a separation ride. . zone which ordinarily will comprise a settler. The lower used catalyst layer is recycled from the Although under some alkylation conditions using a mineral acid catalyst such as sulfuric acid or hydrogen fluoride, it‘is desirable to maintainv 40 being preferably withdrawn from the system and the acid concentration as high as possible, e. g., introduced into a catalyst regeneration zone. T_he by utilizing the highest acid replacement rate,` upper hydrocarbon layer from thersettler is sub that is economically feasible, I have' now found settler to the reaction zone, a portion thereof jected to fractionation for the recovery of gaso line boiling range products and for the separa that good results may be obtained at relatively ' acid concentrations when using a hydrogen tion- 'of unconverted isoparaffins which may be 45 low fluoride catalyst. I have further discovered that recycled to the reaction zone. ' 2,404,393 3 in many cases improved results may loe-obtained by ‘controlling the hydrogen iiuoride dilution . Within a relatively critical range wherein the . optimum quality of alkylation products is ob tained. In one specific embodiment my invention com prises an improvement' in thealkylation of iso paraflins with oleñns in the presence of a hydro ` gen fluoride catalyst wherein the hydrocarbon reaction products are separated from the used `catalyst, said separated hydrocarbon reaction products are subjected to fractionation, at least ‘ a portion of 'said used catalyst is returned to the i alkylation zone, and used catalyst is withdrawn 1 from the system and replaced with catalyst hav 1 ing a higherreffective¿concentrationgof'hi/drogen.; iluOride, saidiirhprovement comprising-the step' lof controlling the withdrawal of used catalyst is used throughout this speciñ'cation and appended claims, it lis intended to include catalysts where in hydrogen ñuoride is the essential active ingre dient. Thus it is Within the scope of my inven tion to employ catalysts containing relatively minor amounts of other materials in addition to hydrogen fluoride. For example, the hydrogen iluoride catalyst may contain minor quantities of Water. While ordinarily commercial “anhy drous” hydrogen ñuorîde will be charged to the alkylation system, it is possible to have as high as about 10 to 15% water‘present in the cata lyst.- Excessive dilution with Water, however, is undesirable since it tends to reduce the alkylating activity of lthe catalyst. Other substances such as :boronptriñuoride whichigmay promotefthe cata lytic activity of hydrogenI fluoride in" alkylation reactions may also be present. The alkylation of isoparainns with oleñns in :ñuoride whereby to maintain the concentration 20 thepresence vof a hydrogen ñuoride catalyst may of hydrogen fluoride in the catalyst phase'within.. . . beLconducted' at a temperature of from about and the addition of more concentrated hydrogen . the range wherein alkylation products of opti ‘mum quality are obtained. In Fig. 1 is shown a schematic; flow 'diagram'v` . `of the type of alkylation process to which my' invention is related. Fig. 2 illustrates graphically the limitations on 0° F., to about 200° F., although the reaction temperature is preferably and more conveniently held‘within -the range of from about 50° F., to about 150° F.' The- pressure on the alkylation ' systemisordinarily just high enough to insure that thehydrocarbons and catalyst are substan ,the useful degree of the dilution of the’catalysttially the liquid phase. The reaction may be phase. subjected to further control by means of the Referring. to„-Fig.- f1; a..1’r.esh`.hydrocarbon` feed 30 _ space -time -which isdeñnedas' thevolume. ,offcat comprisingja-eparaiiin-.oleñnmixture: wherein iso alystA within the.- contacting Zone ;» divided - by, the parañins» area preferably;v present . in substantial volume rate 10er minute of hydrocarbon-react-v molar.- excess-_» over. the: oleI-lns-` is introduced ants charged to the zone. Usually thespace--time îthrough-.lined - into >alkylation zone 2.. This zone Willlie Within the .range of from.»about 5 -to about may; comprise-any;y convenient arrangement. of . w Cil 80 minutes, although; this irange «may inv certain"> equipment“‘.orïapparatus,capable. of effecting-inti cases be-extended :in either direction. -. Itis-prei.-`mate: contacting;l ofv the? hydrocarbon reactants. erable-‘to maintain atall. timesA aÃ~` substantial.. and. catalyst. . A-.fresh.. liquid hydrogen . ñuoride ' catalyst yis introduced ¿throughline .3, Alkylation` molarexcess of.isoparafñns-over oleñns-in the alkylation'zone, -e;.g., from 4-:1 to 10:1 .or higher. zonef2:is..preferably operatedat apressure such 40 The alkylation of isopara?linswvitholeñns,uti» that .-.the catalyst. andhydrocarbons. are.- maine' lizing hydrogen iluoride-.catalysts is, particularly tained substantially in. the-liquid phase.. important in: the.- case-v of'. the :alkylation ..of'"iso-The reaction Amixture :passes .through line «A into butane with.norrnally gaseous oleñnsf such asV separationzone . 5_.which may conveniently ., com7 propylenefor. butylene which are readily; availe prise. a.. settling.. zone; Used. hydrogen fluoride. - able-insubstantial quantities. fromordinary ref catalyst-is removedmthrough . line I 6 ; and intro lining 4sources.. However; kthe process-.may `also l.be` ducedin . part-.into_regeneration zone..7. A sub applied. .to normallyv liquid .isoparaiiinsïandznorf stantial.; portion of.. the. used hydrogen fluoride mally liquid .oleñns It .is..also.zpossibleI to. employ catalyst-removed throughline 6 is recycled' by mixtures of the normally> liquid andnormally means of line 8'to> the alkylationY zone. 2. gaseous hydrocarbons as reactants. generationzone. 1 may comprise any4 eiïective The .term “crude alkylate’? as `.used in .this speci means;eï‘g;,‘ aheating 'or' distillation‘zone; where fication is` intended to designate the totalstaf by puriñed hydrogen ñuoride may be separated bilized: hydrocarbonY reaction products.- ofA the from ‘ the = organic“ contaminants present' in the used: catalyst: Water may also be rerlrioved'fron'il the` used acid' in this zone.` The- regenerated acid'is-tI'í'en-‘WithdraWn to' storage through line IUT-or lmay berecycled through line` l l vtothe al kylatiònïzone.> The organic’contaminants or- re-'-« sidua-l- material ' which " remain“ after ~' the recovery 60 of purified hydrogenlilu'oride xfrom lthe 'used' cata- ~ lysti‘are - withdrawn from theI regeneration zone» thr'oughlline ‘9.1 ' y process; and it thus. includes. not-:only ,thegavia-tion' . gasoline fraction .but also the higherboihngprod.- » uctsof V,the_.reaction. To illustrate more definitely the»~natureof§my` invention I now- refer tothefollowingtable-which:l includes experimental. data obtained- in twelve alkylationv runsl using, a substantially» anhydrous . hydrogen ñuoride. catalyst and. a hydrocarbon. charging stock. having the --followingapproximate - molall composition: 4%. isobutylene,._ 9%. n.-bu-» The '-sep'arated‘hydrocarbon phase passes :from zone-5 bysmeans of line `rl2‘.ir1to lfractionation zone 65 andheavier. Theapparatusfused was arranged.~ I3. Light hydrocarbon gases of the process are>` recoveredihroughlline: I8.-` A low'boiling uncon vertedfzisoparaiiinï. stream' .suchf .asl ' isobutaneY may befre'coveredz' throughîlineî M“- and'is preferably Y recycled; by.“ means Áofîiline; I5: to -alkylation-zonef f 21;. SaturatedM gasoline boiling; range hydrocar--bonsiaresremoved “through line- l 6, and the :higheri boiling ¿hydrocarbon reaction .products are recov eredthrough. line .-I 7. ' in `substantially. the same manner as shown-_iinI Fig.-` 1,. andcomprised essentiallya.mechanically agitated reaction zone of theßturbofmixer type,~.. means. for. charging,fresh_hydrogen;iluoride and.` hydrocarbon reactants-_` thereto»,v a? settling; zone. for» the separation` of used. catalyst fromfthe hy,-4 drocarbonreaction products, afractionation zone: for fractionating-.said hydrocarbon reaction .-prod- à nots, vmeans >for. recycling> the usedcatalyst ».from; ïBythe-termßhydrogen ñuoride eatalyst’.’ which 5 ' the settling zone to thereaction zonefand .mea-ns.-> ¿2,404,393 ' 6 5 from the system. , such as space time, temperature,- composition of for'withdrawing a portion of the used catalyst the fresh charging stock and the combined feed, ‘ Run No. l Series.. 2 3 _. 4 5 6 A 7 8 9 10 11 . B C 0. 0 4. l 9. 3 70. 0 9.1 69. 3 0. 0 4. 1 9. 3 70. 0 l. 7 3. 8 9.1 69. 3 1. 3 4. 1 8.7 69. 7 _. 15. 9 15. 3 15.9 15. 3 15.6 05+ ___________ __ i-Parañin/oleiìu ratio ................................... -_ 0.7 5. 2 0. 8 5. l 0. 7 5. 2 0.8 5. 1 0.6 5. 3 i-Cll’ïl’m n~C4H1o..__ ___-. -___ Conditions: Space time, mim... ............. _. Press., p. s. i. gage.. _____________ __ Temp., ° ............ _. _. 36 1. 7 3. 8 l 35 36 l 36 54 i 53 | 50 9 ‘ 1l 100 Vol. ratio, catalyst/hydrocarbon, 1n reaction zone. _ 1. 1 Catalyst withdrawal rate, cc./hr .... __ _ 12.1 Catalyst addition rate, cc./h _______ __ 20. 0 R. P. M. of agitator in contacting zon Analysis of catalyst phase: ` Total titratable acidity, wt. per cent ................... _- 86. 8 l. 2 8. 4 6. 0 1. 0 3.1 5.5 | 12 l l1 150 ..... _'. .............. _. Water, wt. per cent .................... ._ R l(1)1rganic diluent, wt. per cent ________________ _. es ts: A. S. T. M. Octane No. 0f 275° F. E. P. a1ky1ate.__. 61 . 12 50 1.1 1. 4 1. 2 2. 4 3. 3 7. 2 1750 1. 0 1. 9 4.0 , 1.1 1.1 3. 0 1.0 0.9 0. 9 96. 6 310 102.0 1. 2 1.4 4l. 4 13. 3 48.0 16.0 3500 1. 2 9. 5 11. 0 81.1 73. 2 66. 6 85.3 88. 7 79. 5 1. 9 24. 9 4. 0 29. 4 2. 7 12.0 1.1 26. 0 69.4 1.1 29. 5 92. 1 2.0 16.9 76. 7 1.0 22. 3 72. 9 _ 2. 6 _ 11.1 1.2 6. 7 1.2 10.1 l. 2 19.3 73.1 1. 2 25. 7 , ._ 92. 3 92. 3 92. 7 92. 9 92.1 91.4 92. 7 92.4 92. 4 92.3 92. 5 92.7 - . 22 30 84 198 60 91 162 176 7 18 56 Vol. 275° F. E. P. alkylate/vol. catalyst withdrawn ..... __ 20 27 75 171 54 82 144 153 7 17 51 58 Bronline No. of crude alkylate ____ _r ................... _. 0.1 0.1 0.1 0.2 0.1 0.1 0.2 0.1 0. 1 0.1 0. l ____ __ . Vol. crude alkylate/vol. catalyst withdrawn ______ ._ degree of mixing of reactants and catalyst, water content ofthe catalyst, etc. The effect on the location of the optimum acidity range caused by changing other process variables may be illus trated by comparing the curves for series A and Series A comprising runs 1, 2, 3 and 4 was made at 100° F., 36 minutes space time and 1750 R. P. M. ' on the mechanical agitator in the reaction zone. In series B comprising runs 5, 6, 7 and 8 the space time was .increased to an average value of B which were made at space times of 36 and 55 about 55 minutes with all other conditions the same. Series C comprising runs 9, 10, 11 and 12 was made at 50° F., an average space time of about 11 minutes, and 3500 R. P. M. on the mechanical agitator. The four tests in each se ries were made at decreasing values of total minutes, respectively. The .major effect under the conditions of the two series was merely a general decrease in the octane number level of the prod uct, as the space time was increased over the range of 36 to 55 minutes. However, in the case of series C‘ the space time was decreased, the tem titratable acidity in the catalyst phase in order to illustrate the effect of the hydrogen fluoride concentration under each set of conditions. It can be seen by examining the data for each series that as the total titratable acidity of the catalyst phase in the reaction system decreases, the volume of crude alkylate produced per vol ume of used catalyst withdrawn from the system increases markedly. Substantially the same ef fect is noted in terms of volumes of 275° F., E. P. alkylate produced per -volume of used catalyst withdrawn from the system. It is apparent, then, that a considerable economic advantage accrues by operating at a relatively low titratable acidity since the quantity of desired product obtained at a given hydrogen fluoride replacement rate or a given hydrogen fluoride regeneration cost is substantially improved. ` l However, I have found as a result of experi mental tests that there are limitations on the 66 perature was decreased, and the degree of mixing 4. (as a function of the agitator speed) was in creased with Vthe net result that the optimum range of total acidity was definitely displaced in the direction of higher hydrogen fluoride concen trations. In practical terms this means a higher regeneration rate or catalyst replacement rate is required. While it is thus not possible to establish they optimum range of total acidity which is applicable 1n all cases, it has been found that for many cases, e. g., when alkylating isobutane with propylene,` butylenes, or amylenes, the desirable total acidity will fall within the broader range of from about 65 to about 95%. Moreover, when'isobutane is al kylated with normally gaseous oleiins in the pres ence of a hydrogen fluoride catalyst under sub stantially liquid phase conditions and at tempera tures of from about 50° F., to about 100° F., or useful degree of the dilution of the catalyst phase 60 slightly higher, the optimum octane number prod ucts will be obtained at a total acidity within the since with too great a dilution the quality of the range of from about 70 to about 85%. product is adversely affected. This fact is illus It should be noted that the titratable acidity trated in Fig. 2 wherein the Weight per cent of the catalyst phase within the reaction system total acidity of the catalyst phase has been plotted against the A. S. T. M. octane number of the 275° F., E. P. alkylate product for all three series. It will be seen that for each of the three series _ there is a deñnite optimum range of total acidity wherein the highest octane number product is obtained. ~ ' It is not possible to establish definitely a rela tively narrow range of total acidity which will give optimum results in all cases. The exact op timum range for any case may depend to a con is an eñective measure of the free hydrogen fluor ide concentration. However, it is not necessarily a true measure of the catalytic activity of the catalyst phase unless the complete composition of the phase is known. From the data obtained in these runs, it will be seen that the dilution of the hydrogen fluoride was accomplished largely by the accumulation of organic diluent during the , alkylation reaction. If the same effective dilu tion of the hydrogen iluoride were obtained by the siderable extent on the other process variables 75 addition of water, the catalyst activity would not 2.404,393': 7 While~_in;most instances the< hydrogeniiiuoride charged 4to the falkylation». process vwill be of the commercially “anhydrous” variety which contains several per cent of water, under certain 'conditions 'somewhat larger amounts of water may be present as hereinbe fore described. This, of course, may eiîect the location of the critical rangeV of Ytotal acidity. Previous experienceV has shown that hydrogen ñuoride diminishes greatly in its alkylation ac tivity if more than from about 10% to about 15% acting an isoparaiiîn with an oleñnsinztheefpresv ence of a substantially anhydrous hydrogenv iluoride catalyst, thereby Vforming a catalyst phase containing organic diluent of higher mo lecular weight than the alkylated isoparañîìn, withdrawing used catalyst from and adding more concentrated hydrogen fluoride to the alkylatingf. step, and, by regulation of saidV catalyst .with draWal and addition, controlling the accumula tion of said organic diluent in the catalyst phase Water is present. From the data presented here it is evident that substantially larger amounts of organic-diluent formed. duringthe alkylation to maintain the hydrogen nuoride concentration ofthe catalyst phase within the range ofëlfrom .about 70 to about 85 weight percent. reaction may be present in many cases without an adverse effect on the catalyst activity.y 8 'i 2.; Anv alkylation processi.,-which.comprìscsn’erß4 `3. The process as defined in claim 2 further characterized in that the `withdrawn used cata: y Although‘the mechanism ofthe effect of con lyst is regenerated to separate»hydrogen'ñuoride trolled amounts of organic diluent in the catalyst from organic diluent and the former returned phase is not entirely clear‘it'appears that the to the alkylating‘step vas at least a portionof-'said catalyst activity isl altered by the presence of the 20 more concentrated’ hydrogen Euclide. organic material to such` an extent that unde 4. An alkylation process which comprises‘re- l desirable- side reactions are repressed resulting acting isobutane with a normally» gaseous olefin in improvedquality of the alkylation-products,4 at a temperature of from about 50°F. 'to about said improved quality being evidenced,` for eX 100° F. in the presence of a substantially anhye. ' Y ample, by the'relatively high octane number. It 25 isnot intended, however; that the scope oi-.my invention be limited in any way by this explana-y tion of the effect of the organic diluent. Eromexperimental observations I have 1 shown ‘ drous hydrogen fluoride catalyst,l thereby form ing a catalyst phasecontaining o-rganic diluent of higherV molecular weight vthan the alkylated isobutane, and controlling the accumulationY of said organic diluent. inthe lcatalystv phase;` to that unexpectedmesultsmay be'obtained in the ï 30 maintain the titratable'acidityfoff the catalyst; ` alkylation of isoparañins: with oleñns using. a phase within the range-of from about .'70fto about"` hydrogen fluoride„«'cata1yst` of , relatively high vor 85 weight percent.y ganic diluenticontent; This is contrary to previous experience with mineral. acidialkylation catalysts, sinceit:wouldï'ordinarily be4 expected that the product;qualityVl would decline` continuously with increasing*contaminationïofthel catalyst. I have '5. An alkylation processlwhich comprises rea... acting‘isobutane with a normally gaseous<oleñn\ at a'temperature of. from about 50° F; to about;A 100° inthe presence of a'vsubstantially'f'anhye.î not onflyshownthat good resultscan'be obtained ‘ withvhydrogençfluoride catalysts of relatively low titratable> aciditiesbut Athat under-any` given set >of processing conditions there ís yalso arelatively criticalV range- of totalY acidity which‘must not » i be-exceededv if products-*of optimum vquality are to;be.obtained-. I;claim asmyinvention: 45 1;v An alkylation-»process whichY comprises re- l actingranfisoparamn with an‘oleñn‘in the pres 1 ence of aY substantially anhydrous hydrogen v fluoride» catalyst', thereby. forming a 'catalyst drous hydrogen iiuoride catalyst;;thereby forming: a catalystfphase containingV organic diluent‘zof" .higher molecular weight than the-alkylated‘fisoeA «butane, withdrawing used catalystv from». and? adding more concentrated hydrogen fluorideito the alkylatingstep, and, by regulation ofásaid‘v catalyst withdrawal >and addition, ,controllingtlie accumulation of said'organicfdiluent inthe cat'- f alystphase to maintain; the titratableracidityfof.the catalystv phase within', theA range; off' from~ about 70 to about .85.Weight percent: 6. The process as 'deiined inclaimy 5 further" characterizedîin that the withdrawn vusedlcatat» 50 lystis regenerated to separate hydrogen‘ffluorid‘el lecular weight .than the -alkylated ’isoparafñm andv from'organic diluent and thelformer"returnedfto‘ n] controlling; the.>r accumulation. of: said, organic the alkylating'step‘as at leastìa portioniofrsaidZ y phase;.containingf~~organic diluent of higher mo " diluent in the. catalystiphase to maintain the î hydrogen ñuoride.- concentration ofgthe catalyst l phasefwithinV the range of'fromeabout 703to aboutl ßârweightg'percent. ' more = concentrated hydrogen fluoride; HARRISON C'." ` .