May 23, 1944. H. PINEs- ETAL 2,349,516 ' TREATMENT >0F PAHAFFINS

» Fi-ledMay s1, 1941 T Patented May 23, 1944 2,349,516

UNITED STATES `IPATENT oEFlcE' 2,349,516 TREATMENT or PARAFFINS Herman Pines and Herman S. Bloch, Chicago, lll., assignors to Universal Oil Products Company, Chicago, Ill., a corporation of Delaware Application Maz.’ I l, 1941, Serial No. 396,172 11 Claims. ('Cl. Zim-683.5) This application is a continuation-in-part of lining industry. Both normal butane and iso our co-pending application Serial No. 332,501, butane occur in substantial amounts in natural filed April 30, 1940. gases (in which the normal compound usually This invention relates _to the treatment of predominates), in refinery gases which are paraflìn hydrocarbons of normal or mildly evolved from­ crude petroleum storage tanks, and branched chain structure, and more speciñcally in gases obtainable in the primary distillation> it is concerned with a process for converting of crudes; and they are also present in con parañins of normal and mildly-branched chain siderable percentages in the gases produced in structure into isoparaflins and parallins of more cidental to the cracking of heavy petroleum frac branched chain structure, the process involving 10 tions for the production of gasoline. In the case the use of special catalystsand particular condi of cracked gas mixtures, the relative proportions tions of operation which favor isomerization of iso and normal butanes vary, but the ratio of reactions so that relatively high yields are pro the iso to the normal compound is as a rule con duced of desired branched chain paraflin _hy siderably higher than in natural gas. drocarbons. Butanes may be considered as more or less The formation of isoparañins or more-branched marginal compounds in respect to _their desir chain parañln hydrocarbons from the correspond ability in ordinary gasoline, that is, a certain ing less-branched chain liquid paraflins is desir percentage of them is essential for sufficient able because of the generally higher antiknock vapor pressure to insure ease in starting, While value of the iso-compounds. Furthermore, the 20 an excess tends to produce vapor lock. For these branched chain parafñns both gaseous and liquid, reasons the total percentage of 4-carbon atom which are generally more reactive than the corre hydrocarbons is commonly adjusted in conjunc sponding normal hydrocarbons, may be utilized tion with the boiling range’ and vapor pressure in the production of other branched~chain paraf of the other gasoline components to produce a ñns by so-called alkylation reactions in the pres 25 gasoline of desirable starting characteristics ac ence of suitable catalysts. Also iso-butane may be cording to seasonal demands. dehydrogenated to the corresponding branched Liquid normal paraflins are produced in con chain oleñn which is utilizable for the production siderable quantities in the oil refining industry. ­ of high quality gasoline by a combination of They occur in substantial amounts in natural catalytic polymerization followed by hydrogena 30 gasolines, in the higher boiling constituents of tion of the polymers to form a para?l'lnic motor natural gas commonly known as “casing head fuel of relatively high antiknock value suitable gasoline,” and in gasolines produced in relatively for use in airplane and automobile engines. high yields by the cracking of relatively heavy In one speciñc embodiment the present inven petroleum fractions. In the case of cracked tion comprises a process for isomerizing normal 35 gasolines, the relative proportions of iso and nor or mildly branched paralîn hydrocarbons into mal paramns vary. more highly branched chain paraffin hydrocar An important feature of the present invention ' ' bons which comprises subjecting a mixture of consists in the use of isomerizing catalyst in said normal paraffin hydrocarbons, hydrogen, and separate beds of increasing size and maintained a hydrogen halide to contact, in a plurality of 40 at successively lower temperatures in order to catalyst sections, with separate beds of a com produce a reaction mixture containing a relative posite catalyst `comprising.r essentially a major ly high concentration of isomerized products. proportion of a substantially inert carrier and a This method of operating is superior to iso minor proportion of an aluminum chloride con merization in a single stage at an approximately taining isomerizing catalyst, said catalyst sec 4.5 uniform temperature because of the effects of tions being maintained at successively lower tem temperature upon the speed of isomerization and ’ peratures along the line o1" dow, and having in» the maximum isomerization obtainable when creasing' capacities to permit longer times of con» equilibrium has been reached at any given tem tact as the temperatures are decreased. perature. For example, we have found that with Normal paraffin hydrocarbons with which the i process of the present invention is concerned are normal butane the speed of isomerization in» both gaseous and liquid. Normal butane, which creases with the temperature while the concen tration of isobutane in an equilibrium mixture of _ constitutesbe isomerized a gaseousby the processnormal ofparañin this invention, which is isobutaneand normal butane decreases with in produced in considerable quantities in the oil re 55 creasing reaction temperature as shown 1n the â aeeaeie table, which has been derived from a iarge tact normal butane with aluminum chloride amount of experimental work. carrier composites in the presence of hydrogen and hydrogen chloride at 200° C. to obtain a TABLE butane mixture containing approximately Equilibrium compositions of n-butane ¿iO-50% of isobutane per pass which may be sub ' isobutane mixtures _ jected to contact with the same type of isomeriz ing catalyst in subsequent reactors maintained at lower temperature. Thus, passage of an Temperature, °C. isobutane(approx ) equimolecular mixture of isobutane and normal 10 butano through such an isomerizing catalyst at Per cent 150° C. employing a liquid space velocity of 1 83-90 may result in the production of a butane frac 73-80 63-70 tion containing as high as 70% isobutane, and 55-62 if desired, said fraction may be utilized in al~ 48-52 15 kylation reactions, after which the unconverted normal butane may be recycled to further iso The values listed in the table, however, give no merizing treatment. ` indication of the time required to produce from In accordance with the present invention we normal butane the indicated equilibrium yield have now found that additional beneñts may be of isobutane. At the lower temperatures in the 20 obtained if, in addition to utilizing lower tem indicated range the speed of isomerization is low peratures along the line of flow in a series of . with little or substantially no accompanying side isomerizing reactors, the time of contact be inl reactions, while at higher temperatures the iso< creased to permit time for a further approach merization per pass is greater and the desired to equilibrium conditions. Thus the process is reaction is accompanied by Some _decomposition 25 preferably operated so that successive reactors which results in the formation of lower boiling lhave larger volumes of catalyst. In a process and higher boiling parañins. For example, operating in such a manner that catalyst beds several isomerization runs made in the presence are rotated and their position in the line of flow of a composite of 33% by weight of aluminum is changed in accordance­ with their activity chloride and 67% by weight of charcoal at dif 30 it will be ,necessary when operations are con ferent temperatures on a mixture of normal . ducted in accordance with the present invention butane, hydrogen chloride, and hydrogen pres to provide reactors in various types of parallel ent in_ the respective molecular proportions of connection so that for example the ñrst stage 100, 12, and 3 gave theA following results _when is operated with a single reactor, the second the normal butane was charged at a constant 35 stage with two reactors in parallel and the third liquid space velocity oi' l: stage with three reactors in parallel. This type of mechanical operation is considered to lbe suf , iiciently well known in processes analogous to Per cent convvr‘ the present process so that detailed description sion per pass or normal butano 40 of such manipulation is not necessary. Temperature, °C. into Catalysts suitable for isomerizing paraiiin hy drocarbons according to the process of this inf i-Butanc Propane , vention at successively decreasing temperatures in order to produce a mixture relatively rich in 45 more-branched chain parai’ilns comprise essen l i) tially aluminum chloridefeither alone or mixed with one or more other metal halides. com posited with a porous support such as activated ` Other runs were made on an equimolecular carbon. activated charcoal, pumice, fullerls mixture of normal butane and isobutane in the 50 earth, bentonite. montmorillonite, infusoriai presence of 3-4 mole per cent of hydrogen chlo earth, diatomaceous earth, kieselguhr, silicaE ride and-1 mole per cent oi' hydrogen using a alumina composite, unglazed porcelain, ñrebricir. catalyst composite consisting of 60% of ac etc. Other halides which may be used with alu tivated charcoal supporting 40% by weight of a. minum ' chloride and carriers to produce iso metal halide mixture comprising i molecular merizing catalysts may comprise boron fluoride. proportion of aluminum chloride and 0.57 mo aluminum bromide, and chlorides of beryllium. lecular proportion of zirconium chloride. As titanium. zirconium, columbium, tantalum. shown by the following data, the highest con hafnium, thorium, zinc, iron. copper, etc. centration of isobutane was obtained at . the Temperatures suitable for use in effecting the lowest temperature tried, namely, 150° C. 60 process of this invention are within the approxi» mate range of 25-350" C. and suitable pressures Liquid l Composition oireaction products, range'from approximately 50 to i500 pounds vper "reunierau butano mole per ‘wat ' square inch. IThese temperature and pressure ture, "0. s ace ` ­~>­­ ~-­»~­ ranges include the approximate limits which are ve eeft? i-Butaue Propane n-Bntanc Ct-i feasible. That is. 350° C. is about the highest temperature which can he used in the first of the 150 ...... _. 1.0 61.0 0.6 37.5 0.9 series of reactors and 25° C. is the lowest tem 200 ...... _ 1.0 50.2 6.6 36.2 7.0 250..; .... _. 1.0 45.6 8.5 37.6 8,3 perature which. can he practically employed in the last of a series to obtain suitable _conversion 70 rates. lin regard to times of contact these will These results indicate that the high activity .obviously he varied not only with the actual teun> of ­the catalyst at the higher temperatures re~ _pera-ture and pressure conditions but with the l suited in excessive decomposition and a conse relative activity of different catalyst beds which quent‘lower yield of the desired isobutane. may vary from fresh to completely exhausted Thus we have found it advantageous to con material.

¿at 2,349,518 the catalyst chambers in the several isomeriza the said catalyst maintained at 150° C., so that tion stages are of approximately equal volume the liquid hourly space velocity was about half and increased contact time in the successive that of the iirst stage. The product recovered isomerization stages is obtained by providing an after this treatment contained 80% of isobutane, increasing number of said catalyst chambers ar a yield unobtainable at 200° C. by a single treat~ ranged in parallel. ment without intermediate fractionation. Normal butane may be ycharged through line ~ The character of the process of the present 50 containing valve 5l, pump 52, and line 53 invention and particularly its commercial value containing valve 54' to the first isomerization are evident from the preceding specification and zone 55. Hydrogen chloride is added through example presented, although neither section is line 56 containing valve 5l, pump or compressor intended to be unduly limiting in its generally 58, and line l59 containing valve 60. Hydrogen broad scope. may be supplied through line 5| containing valve We claim as our invention: 62, pump or compressor B3, and line 64 contain 1. A process for isomerizing a paraiiin hydro ing valve 65. 15 carbon to produce more highly branched- deriva The reaction products from the iirst stage are tives thereof which comprises subjecting a 'pro passed through line 66 containing valve 6l, cooler portioned mixture of said hydrocarbon, hydro $8, and line 69 to manifold 10. This stream is gen and a hydrogen halide to contact with suc then split and directed through valves 1l and cessive sections of a composite catalyst compris 'l2 to catalyst chambers 13 and 14 wherein fur 20 ing essentially a major proportion of a substan , ther isomerization is effected at a lower tem tially inert carrier and a minor proportion of perature and increased Contact time. The a metal halide-containing catalyst, said sections eilluent reaction products are Withdrawn` through being maintained at successively lower tempera manifold l5 containing valve 16 and 'l1 and are tures and having increasing volumes as the tem then supplied through line 18 to cooler 79 and 25 peratures are decreased. thence through line 86 to manifold al. The 2. A process for isomerìzing normal butane to reaction mixture is directed through valves 32, produce substantial yields of isobutane therefrom 83, and 8# to catalyst chambers 85, 86?, and 87 which comprises subjecting a proportioned mix wherein the isomerization reaction is allowed to­ ture of­ said normal butane, hydrogen, and a proceedto a further extent at a still lower tem 30 hydrogen halide to contact with successive sec perature and greater contact time. The ilnal ‘ tions of a composite catalyst comprising essen reaction products are removed through valves tially a major proportion of a substantially inert 89, 90, and 9i to manifold B8 and thence through carrier and a minor proportion of a metal halide line 92 to fractionator 93. , containing catalyst, said sections being main­ In zone 93 hydrogen chloride and/or hydro 35 tained at successively lower temperatures­ and gen are removed overhead through line 94 con having increasing volumes as the temperatures4 taining valve 91 and are recycled by means of are decreased. pump or compressor 99 and line 99 containing 3. A process for isomerizing a parañin hydro valve l0@ to line 53. If desired, a portion of carbon to produce more highly branched deriva the mixture in line 96 may be vented through 40 tives thereof which comprises subjecting a pro- v line S5 containing valve Se. Isobutane is recov- t portioned mixture of said hydrocarbon, hydrogen ered through line> 50i and valve l2. Uncon and hydrogen chloride to contact with successive verted normal butane may be withdrawn through sections of a composite catalyst comprising es line E03 containing valve Mld and is preferably sentially a major proportion of a substantially recycled to isomerization zone 55 by means of inert carrier and a minor proportion of an alu line £05 containing valve lilß. Higher~ boiling minum chloride-containing catalyst composite, reaction products are removed through line lill said sections being maintained at successively containing valve Wd. lower temperatures and having increasing vol Although Figures 1 and 2 depict the use of umes as the temperatures are decreased. three isomerìzation. stages, it wi11 be apparent . 4. A process for isomerizing normal butane to that any desired number of two or more reac produce substantial yields of isobutane therefrom tion stages may be provided. which comprises subjecting a proportioned mix The following numerical data are presented ture of said normal butane, hydrogen and hydro to indicate some of the results obtainable in gen chloride to contact with successive sections isomerizing paraflin hydrocarbons by the present of a composite catalyst comprising essentially process, although it is not intended to thereby a major proportion of a substantially inert car limit the scope of the invention: rier and a minor proportion of an aluminum EXAMPLE chloride-containing catalyst composite, said sec~ tions being' maintained at successively lower tem Normal butane was passed over a catalyst con GU peratures and having increasing volumes as the sisting of 60 parts by Weight of activated char temperatures are decreased.v coal and e0 parts by weight of a composite of l 5. A process for isomerizing a parafñn hydro molecular proportion of aluminum chloride and carbon to produce more highly branched deriva 0.7 molecular proportion of zirconium chloride. tives thereof which comprises subjecting a pro This treatment, in the presence of 6 mole per portioned mixture of said hydrocarbon, hydrogen cent of hydrogen chloride and l mole per cent and hydrogen chloride to contact with successive of hydrogen at 200° C. under a pressure of 650 sections of a composite catalyst comprising es pounds per square inch with 2.0 liquid space sentially a major proportion of a substantially velocity of charge, yielded 40% oi’ isobutane per inert carrier and a minor proportion of an alu pass. _ minum chloride-containing catalyst composite. The mixture of isobutane, normal butane, hy said sections being maintained at successively drogen and hydrogen’chloride, as Well as pro lower temperatures with a range having as its pane, pentane, etc. formed in the ñrst reactor upper limit 350° C. and as it lower limit 25° was next passed through a second and larger C. and having increasing volumes as the terr­ reactor containing about double the volume of peratures are decreased. `2,349,516 5 6. A process for isomerizing normal butane tions being maintained at successively lower tem to produce substantial yields of isobutane there peratures with a range having as its upper limit i from which comprises subjecting a proportioned 350° C. and as its lower limit 25° C., and having mixture of said normal butane, hydrogen and increasing volumes as the Vtemperatures are _de hydrogen chloride to contact with successive sec creased. f tions of a composite catalyst comprising essen 9. A process for isomerizing 'paraiïlns whichv tially a maior proportion of a substantially inert comprises passing the same in series through a carrier and a minor proportion of an aluminum plurality oi.' solid masses comprising an isomeriz chloride-containing catalyst composite, said sec ing catalyst, and maintaining said masses at suc tions being maintained at ~successively lower cessively lower isomerizing temperatures in the temperatures with a range having as its upper direction of flow of the parafllns therethrough, limit 350° C. and as its lower limit 25°- C., and said masses being of increasing volume in the having increasing volumes as the temperatures direction of decreasing temperatures, whereby

are decreased. . „ . to provide a longer contact time in the last than 7. A process for isomerizing a parailln hydro in the first mass oi the series. carbon to produce more highly branched deriva» 10. A process for isomerizing paraflin hydro~ tives thereof which comprises subjecting a pro carbons which comprises passing the parailins portioned mixture of said hydrocarbon, hydrogen in admixture with a hydrogen halide through a and hydrogen chloride under a superatmospheric plurality of solid masses comprising‘a metal hal pressure of from about 50 to about 1500 pounds 20 ide isomerizing catalyst, and maintaining said per square inch to contact with successive sec masses at successively lower isomerizing tem tions of a composite catalyst‘comprising essen peratures in the direction of flow of the par tially a major proportion of a substantially inert aiilns therethrough, said masses being of increas carrier and a minor proportion of an aluminum ing volume in the direction of decreasing tem chloride-containing catalyst composite, said sec 25 peratures, whereby to provide a longer contact tions being maintained at successively lower tem time in the last than in the ilrst mass of the

peratures with a range having as its upper'limit series. . i , 350° C. and as it ­lower limit 25° C., and having 11. A process for isomerizing parailin Ahydro increasing volumes as the temperatures are de ` carbons which comprises passing the paranins

creased. ` , _ 30 in admixture with hydrogen chloride through 8. A process for isomerizing normal butane to a plurality oi solid masses containing aluminum produce substantial yields of isobutane there chloride, and maintaining said masses at suc from which comprises subjecting a proportioned cessively lower isomerizin‘g temperatures in the mixtureI of said normal butane, hydrogen, and direction of flow of the parailins therethrough, hydrogen chloride under a superatmospherlc said masses being of increasing volume in the pressure from about 50 to about 1500 pounds direction of decreasing temperatures, whereby per square inch to contact with successive sec­' to provide a longer contact time in the last than` tions of a composite catalyst comprising essen in the first mass oi the series. . \ v tially a maior proportion of a substantially inert HERMAN PINES. carrier and a minor proportion of an aluminum 40 HERMAN S. BLOCH. chloride-containing catalyst composite, said sec