Патент USA US2402807код для вставки
Patented June 2-5, 1946 ' 2,402,807 ‘ UNITED STATES PATENT OFFICE ISOMERIZATION OF HYDROCARBONS Gustav Eglo?, Chicago, 111., assignor to Universal Oil Products Company, ChicagoJlL, a corpora " tion of Delaware No Drawing. Application May 25, 1942, . ‘ Serial No. 444,430 11 Claims. (Cl. 260-6835) 1 2 This invention relates to a process for the pro duction of highly branched para?in hydrocarbons Y from normal or mildly branched para?in hydro carbons by catalyzed isomerization reactions, and the process is more specifically directed to the manufacture or 2,2,3-trimethylbutane, which hydrocarbon is generally known as triptane. In the para?in hydrocarbon series, it has been established as a general rule that the more highly branched compounds have higher knock ratings than their less highly branched isomeric counter parts. Thus, the iso-octane having the structure 2,2,4-trimethylpentane has been accepted for treatment in admixture with the normal heptane, further subjecting the 90-92° C. fraction in a second step to contact with metal halide hydrogen halide catalysts at a lower temperature to produce substantial yields of dimethylpentanes, , fractionating the products from the second step to produce a fraction boiling from about 75 to about 90° C. and comprising said dimethyl ' pentanes, and a higher boiling fraction which 10 is recycled to further isomerization, subjecting the 75-90° C. fraction in a third step to contact with metal halide-hydrogen halide catalyst to ‘ effect furtherisomerization of said pentanes and fractionating the products from a third step or hydrocarbon mixtures in respect to their anti .15 to recover a fraction boiling between about '19 knock value when used as fuel in standard test and about 81° C. comprising 2,2-dimethyipentane, some time as a standard for rating hydrocarbons engines. In contrast to the antiknock value of 2,4-dimethy1pentane and 2,2,3-trlmethylhutane, this compound which is usually rated as 100, the while recycling higher boiling materials to fm'ther antiknock value of normal heptane is placed as isomerization treatment. 0, so that these two hydrocarbons represent the 20 In accordance with the. principles of the present limits of an arbitrary scale of values employed invention the isomerization of normal heptane in evaluating the antiknock properties of hydro is accomplished progressively in a series of steps carbons. in which conditions of isomerization are modi?ed Itis known in the artlthat substantial yields to favor equilibria corresponding to the produc of branched isomers can be produced from nor 25 tion of the most highly branched isomer triptane. mal para?ln hydrocarbons by contacting the lat Thus,‘ the temperatures employed in the succes ter with catalysts oi‘ the Friedel-Crafts type, par- . sive steps are progressively decreased. In the ticularly such compounds as aluminum chloride, . ?rst step in which normal heptane undergoes aluminum bromide, zirconium chloride, zinc chlo primary isomerizatiori into methyl hexanes and ride, ferric chloride and others in the presence 30 ethyl pentanes, temperatures of from about ll to of hydrogen halides such as hydrogen chloride about 75° C. may be employed depending upon 01' hydrogen bromide. In e?ecting such isomer the activity of the metal halide-hydrogen halide izations it has been found that anlequilibrium catalysts used for effecting isomeriaatiom In between the possible isomers is usually reached this step pure aluminum chloride or aluminum . under the .conditions of operation depending 35 bromide may be used along with substantial; principally upon the factors 01' temperature and amounts of hydrogen chloride or hydrogen time of contact with a selected catalyst, although bromide and in order to produce maximum other factors such as the presence of varying amounts of the methyl hexanes and ethyl amounts of hydrogen halides and hydrogen may pentanes, the time of contact with the composite influence the equilibrium actually attained. In 40 isomerizing catalyst is keptrelatively short, and the present process use is made of the equilibria emphasis is placed on a relatively high recycle attained in the step-wise isomerization 0! normal‘ rate of unconverted normal heptane to insure Dara?lns to e?'ect - a degree or isomerization 'high yields of the desired primary isomerization hitherto unattained in such processes. In one speci?c embodiment the present inven 45 products. Following the primary isomer-isms step; the products are fractionated to recover an tion comprises a process for the manufacture of triptane from normal heptane which consists in ' isomer fraction boiling ‘from about 90 to about 92° C. which consists largely of methyl hexane‘, subjecting said normal heptane to‘ contact with using fractionators or capacity adequate for e! a metal halide-hydrogen halide catalyst in the primary stage to effect a limited isomerization 50 fecting a relatively sharp separation of this cut. The boiling point of 2-methyl hexane at "180 mm. with the production of methyl hexanes and ethyl pressure is 90.1° C. and that 01' B-metiwl hexane pentanes, iractionating the products to produce a cut boiling from about 90 to about 92° 0. com , is 91.9“ c. so that theta-92° 0. cut will conskt P 'ising said hexanes and said pentanes, and largely of these two compounds and the recycled heavier iractions which are recycled to further. 55 materialwhichis returnedtoturtherisomerillng 2,402,807 3 4 treatment will consist principally of unconverted normal heptane and some ethyl pentanes. In the foregoing paragraphs a description has been given of the essentia1 steps of the present In the second step of the process the methyl hexane fraction boiling from about 30 to about 92° C. is further isomerized to produce a mix ture of 'dimethyl pentanes. In this step the temperature employed is lower than that em ployed for the primary step and will be some where within the range of —25 to 50° C., depend process without regard to non-essential details of the operation. In this respect each of the successive steps may be carried out in any de sired manner to accomplish the stepwise pro duction of isomers with an increased degree of ' hydrocarbon chain branching. —Thus, the steps may be conducted in batch operation by merely' ing again on the activity of the catalyst andthe 10 charging the material to be isomerized into re-v action vessels capable of withstanding pressure amount of hydrogen halide used. In general, the conditions employed in the second step will be modi?ed in the direction of decreased isomer izing activity, and in this step in order to avoid undesirable side reactions involving decomposi tion rather than isomerization of the hydrocar bons, hydrogen may be introduced to the isom erizing zone in molecular form or it may be gen along with the catalyst and added hydrogen and the reactants subjected to heating for a limited period of time after which the reaction products 15 are fractionated, although such operations are not favored since they do not permit the use of the preferred short times of reaction correspond- ' ingto limited conversions. erated in situ by interaction of added hydrogen Continuous operations may be conducted by chloride with metals in admixture with the metal 20 passing the hydrocarbon mixtures charged to each step along with hydrogen chloride and, if halide. Similarly, instead of using aluminum desired, hydrogen through stationary beds of chloride in the second step, its action may be’ modi?ed by the presence of other metal halides granular metal halides followed by continuous fractionation with recovery of the desired cuts such as, zinc chloride, zirconium chloride or fer ric chloride. Again, contact times are preferably 25 for further isomerization, such operations‘ in short to favor the production of the dimethylpen volving the‘ use of alternate reaction and frac tanes as the principal products of the secondary tionation zones with passage of the primary isomer fractions to succeeding stages and re step. After the isomerization has been effected ‘ to the desired degree, the dimethylpentanes are cycle of hydrogen chloride and unconverted hy- ' recovered by separating a fraction boiling within 30 drocarbon fractions back to preceding stages. Granular catalysts used in this type of operation the approximate range of 75 to 90° C. by the use of fractionating apparatus of suitable design and may consist of particles of the metal halides capacity. Boiling points of the dimethylpentanes themselves or particles consisting of granules of relatively inert supporting materials to which are given below: 35 the metal halide has been added by any suitable method. Examples‘ of such catalyst supports are Dimcthylpentane 1:131:11‘? such substances as activated carbon, prepared aluminum oxides, bauxite, clays, kieselguhr and . ° C. other more or less refractory materials having 40 varying absorptive capacities. 2,2dimethylpcntanc. . 2,4-dimethylpe tone. _ 79. 2 80. 7 3,3~dimethylpentane _ . 86. 0 Another type .of continuous operation which 2,3-dimethylpentanc ___________________________________ . _ 89. 8 may be employed in any one or all of the three The hydrocarbon fraction boiling above 90° C. _ steps of the process consists in passing the hydro carbon or hydrocarbon mixture to be isomerized is recycled either to the recycle primary step or 45 through 'a bed of granular metal halide in the absence of a hydrogen halide under conditions to the secondary step for further isomerizing of temperature and pressure at'which the hydro carbon mixture dissolves the metal halide, and In the third step of the process the recovered passing solution of metal halide and hydrocarbon dimethylpentanefraction boiling from about 75 to about 90° C. is further contacted with metal 50 along with added hydrogen halide into a reactor packed with granular materials which are gen halide-hydrogen halide catalysts at still lower erally inert and have varying absorptive capaci temperatures, preferably below —35" C. and the treatment. ‘ - ties for the metal halide dissolved in the hydro carbon. In such processes the dissolved metal and hydrogen halide is proportioned to favor the production of the more highly branched 55 halide is deposited upon the granules in the re actor and isomerization ensues in the presence isomers without fostering decomposition reac catalyst composite consisting of the metal halide of the added hydrogen halide. In this scheme of operations fresh surfaces'of metal halide are continually exposed so that catalytic activity in tion in respect to temperature, catalytic activ ity, contact time, etc., substantial yields of the 80 the packed reactor is maintained over extended tions. In this third and ?nal stage of the proc- ' css, under suitably chosen conditions of opera desired triptane are produced and by fractionat ing to produce a ‘IQ-81° C. fraction from the hy drocarbon products, a mixture consisting of 2,2, and 2,4-dimethylpentanes and 2,2,3-trimethyl periods of time while metal halide-hydrocarbon complexes may 'flow downwardly to be removed at the bottom of the packed reactor, or are ab sorbed in the pores of the granular material. butane is recovered. The normal boiling points 65 Other types of isomerization procedures which of the dimethlypentanes have been given above. may be used in the steps of the process include The normal boiling point of the desired triptane those in which a stream ‘of the vapors of the hydrocarbons tobe isomerized carries powdered is 80.9° C., and it is, therefore di?icultly sepaq ‘table from the 2,4-dimethylpentane. However, ‘metal halide catalyst upwardly through a reac as will be shown in later examples, it is pro tion chamber to which hydrogen chloride or hydrogen halidev is added to e?ect the-desired .duclble in substantial"concentrations in admix- ~ ture with the dimethyl pentanes to form hydro isomerization, the powdered metal halide being carbon mixtures or exceptionally high antlknock r‘ separated in a succeeding chamber, subjected to Value. ~ ‘ ‘u any reactivation steps which are necessary to 2,402,807 , 5 6 . presence of a hydrogen halide to contact with a metal halide catalyst in a. primary stage under restore its activity and then returned to further contact with incoming hydrocarbon vapors. . ‘ The following example'is introduced to illus conditions adequate to produce substantial yields of methyl hexanes, separating said methyl trate the results which are normally'obtainable hexanes and subjecting them in a secondary stage to contact with a metal halide catalyst in the presence of a hydrogen halide under condi tions adequate to produce substantial yields of di in the use of the process although the scope of ‘ theinvention is ‘not intended to be limited in exact accordance therewith. Normal heptane is subjected to isomerization by passing it at a temperature of 75° C. upwardly through a granular catalyst bed containing gran ular composite material consisting of 80 per cent by weight of activated alumina and 20 per cent ‘tones and subjecting them in the presence of a hydrogen halide in a tertiary stage to contact with a metal halide catalyst under conditions by weight of aluminum chloride. Five mole per adequate to produce substantial yields of triptane. methylpentanes, separating said dimethylpen 2. A process for the isomerization of normal 15 heptane to produce triptane therefrom which cent of hydrogen chloride in respect to the nor mal heptane is admitted along with the hydro carbon. comprises subjecting said normal heptane in the The hydrocarbon products from the presence of a hydrogen halide to contact at a temperature of from about 0 to about 75° C. with a metal halide catalyst in a primary stage to pro lsomerizing step are fractionated to remove prod ucts boiling below 90° .C. and recover the hydro carbon fraction boiling from 90 to 92° C. com prising principally Z-methyl and 3-methyl hex 20 duce substantial yields of methyl hexanes, sepa rating said methyl hexanes and subjecting them ane. The products boiling below 90° C. are fur in the presence of a hydrogen halide in a sec ther fractionated to recover hydrogen chloride ondary stage to contact at a temperature of from which is recycled to mix with the normal heptane about —25 to about +50° C. with a metal halide charge and a fraction boiling above 92° C. and comprising 85 per cent normal heptane is re 25 catalyst to produce substantial yields of dimethyl pentanes, separating said dimethylpentanes and cycled to further contact with the granular cata subjecting them in the presence of a hydrogen lyst. The"90-92° C. fraction continuously pro halide in a tertiary stage to contact at a tem duced with recycling of unconverted material is perature below —35° C. with a metal halide cata- ‘ equal to 70 per cent by volume of the normal lyst to produce substantial yields of triptane. heptane charge. ' The 90-9,2° C. fraction is contacted with another I 3‘. A process for the isomerization of normal ‘ heptane to produce triptane therefrom which stationary bed of the same type of catalyst em - comprises subjecting said normal heptane in the ployed in the first step at a temperature of 0° C. ,presence of a hydrogen halide to contact at a in the presence of 5 mole per cent of hydrogen ‘chloride based on the mixture‘of methyl hexanes 35 temperature of from about 0‘to about 75° C. with a metal halide catalyst in a primary stage, frac~ charged. The products from the second step are tionating the products from said primary stage fractionated to produce hydrogen chloride which into hydrogen halide, hydrocarbons boiling below is recycled in the same step, a 60 volume per cent 90° C., a hydrocarbon fraction boiling from about yield of a hydrocarbon fraction boiling from 75 to 90° C. and a heavier fraction boiling above 40 90 to about 92° C. and a higher-boiling hydro carbon fraction, returning said hydrogen halide and said higher-boiling hydrocarbon fractions to further contact with said metal halide catalyst dergo further isomerization in admixture with in the primary stage, removing hydrocarbons the methyl hexane fraction. ‘ ' The 75~90° C. fraction comprising dimethyl 45 boiling below 90° C., subjecting said fraction boil ing between about 90. and about 92° C. in the pentanes is now contacted with a granular com- ~ , presence of a hydrogen halide to contact at a tem posite catalyst consisting of activated alumina perature of from about —25 to about +50° C. supporting an equimolar mixture of aluminum with a metal halide catalyst in a secondary stage, chloride and aluminum bromide at a tempera ture of —40° C.,. the liquid hourly space velocity 50 fractionating the products from said secondary 90° C. and containing ethyl pentanes. The last named fraction is continuously recycled to un of the hydrocarbon mixture in respect to the volume of catalyst being 0.05. The eiiluent materials from this catalytic con~ tact are continuously fractionated to separate the added hydrogen halides for recycling, and 55 to produce a 50 per cent yield of a '79-8l° C. frac tion and higher boiling products which are re cycled to further isomerizing treatment in ad mixture with the dimethylpentanes. Analysis of stage‘to produce hydrogen halide, compounds boiling below 75° C., a fraction boiling from about 75 to about 90° C., and a higher-boiling hydro carbon fraction, returning said hydrogen halide and said higher-boiling hydrocarbon fraction to further treatment in said secondary stage, sub jecting said fraction boiling from about 75 to about 90°C. in the presence of a hydrogen halide to contact at a temperature below -35° C. with a v the 79-81° C. fraction indicates the presence of 60 metal halide catalyst in a tertiary stage, frac tionating to produce hydrogen halide, compounds 60 per cent of a mixture of 2,2 and 2,4-dimethyl boiling below ‘79° 0., a hydrocarbon fraction boil pentanes and 40 per cent of 2,2,3-trimethylbu ing from about 79 to about 81° C. and a higher time. The octane number of this fraction is found boiling hydrocarbon fraction, removing said com to be 95 in comparison with a standard 2,2,4 trimethylpentane. 4 v ' By the above described operation there is thus continuously produced a 21 per cent overall yield of 95 octane number hydrocarbon material based on the normal heptane charge, the yield of trip tane being-8 per cent by volume based on the 70 heptane charged. “ ‘ Iclaim asmy invention: ‘ pounds boiling below '79? (2., returning said hy drogen halide and said higher-boiling hydrocar bon fraction to further treatment in said tertiary state and recovering said fraction boiling from about 79 to about 81° C. ‘ 4. A process for the isomerization of normal heptane ‘to produce triptane therefrom which comprises subjecting said normal heptane in the 1. A process for the isomerization oi.’ normal presence of hydrogen chloride to contact with r1 heptane to produce triptane therefrom-which aluminum chloride catalyst in a primary stage comprises subjecting said normal heptane in the 75 under conditions adequate to produce substantial 2,402,807 7 . yields of methyl hexanes, separating said methyl‘ higher~boiling hydrocarbon traction, returning hexanes and subjecting them in the presence of hydrogen chloride in a secondary stage to contact with an aluminum chloride catalyst under condi said hydrogen chloride and said higher boiling hydrocarbon fraction to further treatment in said tertiary stage and recovering said traction boil ing from about '79 to about 81°_ C. ‘ tions adequate to produce substantial yields oi dimethylpentanes, separating said dimethylpent 7. A process for the treatment of normal hep anes and subjecting them in the presence oi.’ hy tane to produce isomeric heptanes therefrom drogen chloride in a'tertiary stage to contact with which comprises subjecting said normal heptane an aluminum chloride catalyst under conditions in the presence or a hydrogen halide to contact adequate to produce substantial yields of trip 10 with a metal halide catalyst in a primary stage tane. under conditions adequate to produce substan 5. A process for the isomerization of normal tial yields of methyl hexanes, separating said heptane to produce triptane therefrom which comprises subjecting said normal heptane in the methyl hexanes and subjecting them in a sec ondary stage to contact with a metal halide cata presence of hydrogen chloride to contact at a 15 lyst in the presence 01 a hydrogen halide under temperature of from about 0 to about ‘75° C. with conditions adequate to produce substantial yields an aluminum chloride catalyst in a primary stage of dimethylpentanes, separating said dimethyl to produce substantial yields of methyl h'exanes, pentanes and subjecting them in the presence of separating said methyl hexanes and subjecting a hydrogen halide in a tertiary stage to contact them‘ in the presence of hydrogen chloride in a 20. with a metal halide catalyst under conditions secondary stage to contact at a temperature of adequate to produce substantial yields of other isomeric heptanes. from about --25 to about +50“ C.- with an alu minum chloride catalyst to produce substantial 8. A process for the treatment of normal hep yields of dimethylpentanes, separating said di tane to produce branched chain hydrocarbons methylpentanes'and subjecting them ‘in the pres therefrom which comprises subjecting said nor ence of hydrogen chloride in a tertiary stage to 25 mal heptane in the presence of hydrogen chlo contact at a temperature below —35° C. with an ride to contact at a temperature of from about aluminum chloride catalyst to produce substan 0 to about 75° C. with an aluminum chloride tial yields of triptane. v catalyst in a primary stage to produce substan 6.‘ A process for the isomerization of normal tial yields of methyl hexanes, separating said comprises subjecting said normal heptane in ad mixture with hydrogen chloride tocontact at ya vtemperature of from about 0 to about 75° C. with ence of hydrogen chloride in a secondary stage to contact at a temperature of from about —25 to heptane to produce triptane therefrom which 30 methyl hexanes and subjecting them in the pres about +50° C. with an aluminum chloride cata an aluminum chloride catalyst in a primary 35 lyst to produce substantial yields of dimethyl - stage, iractionating the products from said pri pentanes, separating said dimethylpentanes and mary stage to produce hydrogen chloride, hydro subjecting them in the presence of hydrogen chlo ride in a tertiary stage to contact at a tempera ture below ~35° C. with 'an aluminum chloride carbons boiling below 90° C., a hydrocarbon frac tion boiling from about 90 to about 92° C. and 'ahigher-boilin-g hydrocarbon fraction, returning 40 said hydrogen chloride and said higher-boiling hydrocarbon fraction to further contact with said aluminum chloride catalyst in said primary stage, removing hydrocarbons boiling below 90° (3., sub jecting said fraction boiling between about 90 45 catalyst. ‘ . 9. A process for producing triptane which com prises isomerizing normal heptane under condi tions regulated to produce methyl hexanes and ethyl pentanes therefrom, separating from the resultant products a fraction boiling from about and about 92° C. in admixture with hydrogen ‘ '90“ C. to aboutv 92° C., subjecting said fraction chloride to contact at a temperature of from“ about —25 to about +50° C. with an aluminum to controlled isomerization to produce dimethyl pentanes therefrom, separating-from the prod chloride catalyst in a‘ secondary stage, fraction ucts of the last-mentioned step a fraction boiling ating the products from said secondary stage to 50 from about 75° C. to about 90° C., and subjecting produce hydrogen chloride, compounds boiling the last-named fraction to 'isomerizin'g conditions below 75° C., a fraction boiling from about 75 regulated to convert a portion thereof into 2,2,3 to about 90° C., and a higher-boiling hydrocarbon ~ trimethylbutane. , w traction, returning said hydrogen chloride and 10. A process for producing triptane which said higher-boiling hydrocarbon fraction to fur 55 comprises subjecting a mixture of dimethylpen ther treatment in said secondary stage, subjecting tanes to the action of an isomerizing catalyst at said traction boiling from about 75 to about 90° an isomerizing temperature below —35° C. C. in admixture with hydrogen chloride to con 11. A process for producing triptane which tact at a temperature below -35° C. with an comprises subjecting a mixture of dimethylpen aluminum chloride catalyst in a tertiary stage, 60 tanes to the action of an aluminum halide and a Iractionating to produce hydrogen chloride, com pounds boiling below '19"v C., a hydrocarbon trace tlon boiling from about '79 to about 81° C. and a hydrogen halide at an isomerizing temperature below -35° C. ' ‘ \ ' GUSTAV EGLOFF. _ '