US2385543A - Cycloparaffin production - Google Patents

Description

sept. 25, 1945.4 w. E. 505s Er AL 2,385,543

GYCLOPARAFFIN PRODUCTION Filed May 5l, 1944 Fmdonaf 02 Patented Sept. 25, 1945 umn-:v STATES wrmur ori-'ics y i amsn l CYMPABAFFIN PIODUUI'ION Company. Ban of Delaware Calif.. a corporation Application May 81, 1944, Serial No. 588.192

17 Claims. (Cl. 26o-666) This invention relates to an improved process for the separation of cycloparaiiins from hydrocarbon mixtures comprising cycloparafllns in admixture with open chain parafllris. The invention relates more particularly to an improved process for the production of cycloparaiiins of hydroaromatic structure from hydrocarbon fractions comprislng open chain paraflins and cycloparamns of non-hydroaromatic structure.

The cycloparailins have become of exceeding importance as starting materials and intermediates in 'the production of a wide variety of or' ganic products. The most fertile source of these highly desirable materials resides in the hydrocarbon mixtures obtained in the natural state as petroleum `and in the products obtained in the thermal or catalytic treatment of petroleum or distillate fractions thereof, and in the thermal or catalytic treatment such as, for-example, hydrogenation, of carbonaceous materials, etc. As is well known, the cycloparailins in these readily available hydrocarbon mixtures are found therein in admixture with open chain paraiiinsr Realization of the full advantages inherent in the many chemical processes relying upon the cycloparafllns as lstarting or intermediate material has heretoforebeen seriously handicapped by the lack of a process enabling the efficient separation on a practical scale of the cycloparafllns from the open chain parafdns in admixture with which they are generally encountered. Thus, separation of the cycloparaiiins from open chain parafiins having the same or approximately the same number of carbon atoms to the molecule by such methods as fractional distillation, if at all possible, is often rendered so complex and delicate an operation as to render it impractical.

Of the cycloparaiiins, those of hydroaromatic structure are presently of particular value and ilnd application in the production of an exceedingly wide range of valuable organic products. 'Ihe production of the cycloparaflins of hydroaromatic structure in a state of required purity is rendered even more diicult since to the difiiculty of their separation from open chain paramns is added the often equally vexing problem of their separation from isomeric non-hydroof close boiling range or capable of forming azeotropes therewith. By the term hydroaromatic cycloparaillns as used throughout this specification and appended claims is meant the cycloparafiins having a hexamethylene ring such as, for example, cyclohexane and the alkyl cyclohexanes, to distinguish them from cycloparaflins aromatic cycloparamns and other hydrocarbons 3f non-hydroaromatic structure comprising those having pentamethylene rings such as. for example, methylcyclopentane and the alkyl cyclopentanes.

It has been suggested heretofore to subject the hydrocarbon mixtures comprising open chain parailins and cycloparamns of non-hydroaro-r matic structure to isomerizing conditions effecting the conversion of non-hydroaromatic cycloparaillns to hydoaromatic cycloparamns and thereafter subject the entire hydrocarbon mixture to fractionation to separate fractions comprising desired cycloparafilns. Although such a procedure enables the concentration on a. practical scale of certain of the cycloparafiins such as, for example, cyclohexane, it still does not enable the attainment of desired yields in even such specific instances. It furthermore does not eliminate to a sumcient degree the difficulties of separation. Thus, for example, in the production of cyclohexane from hydrocarbon mixtures comprising Cc paramns and methylcyclopentane. the available raw material must first be subjected to a fractionation resulting in the production of a methylcyclopentane concentrate. In so doing, a considerable amount of valuable cyclohexane originally present in the available raw material as well as a certain amount of methylcyclopentane, is left in the higher boiling fraction from which the methylcyclopentane concentrate is separated. Such methods furthermore offer limited advantages in ony such specific cases. They do not provide a practical answer, for example, to the production of hydrocarbons predominating in methylcyclohexane from the readily available hydrocarbon mixtures comprising the non-hydroaromatic cycloparafns having seven carbon atoms to the molecule in admixture with close boiling open chain paramns having seven and eight carbon atoms to the molecule. In such case the problem of separation is in no wise overcome by isomerizing the mixture as a Whole under conditions resorted to heretofore.`

In its broadest aspect, the obiect of the present invention is to provide an improved process enabling the more eilicient separation cf cycloparaiiins from hydrocarbon mixtures comprising cycloparains and open chain parailins.

A more particular object of the invention is the provision of a process enabling the more eiiicient separation of cycloparaflins from hydrocarbon fractions comprising cycloparaiins and open chain parailins having substantially the same number of carbon atoms to the molecule.

A further object of the invention is the providroaromatlc structure from hydrocarbon mixtures comprising cycloparaiilns and open chain parafilns with simultaneous conversion. during the separation, of the non-hydroaromatic cycloparaflins to hydroaromatic cycloparafllns.

' Another object of the invention is the provision of an improved process'for the production of hydrocarbons predominatingrin cyclohexane from hydrocarbon fractions comprising open chain hexanes and methylcyclopentane.

Still another object of the invention is the provision of an improved process for the more eilicient production of methylcyclohexane from hydrocarbon fractions comprising open chain paraiiins and cycloparailins of non-hydroaromatic structure having seven carbon atoms to the molecule. Other objects and advantages of the invention will become apparent from the following description thereof.

It is known that unsaturated hydrocarbons such as oleiins and aromatic hydrocarbons which can react readily with an aluminum chloride. are removed from hydrocarbon mixtures containing them by treatment with aluminum chloride. It has now been found thatl saturated hydrocarbons of cyclic structure comprising the cycloparaiiins can be separated efficiently by extraction under suitable conditions with a preformed complex obtained by the interaction of a metal halide of the Friedel-Crafts type and an organic compound. It has been found that by selection of suitable conditions, the cycloparaiilns of nonhydroaromatic structure present in the hydrocarbon mixture treated are converted to, and separately recovered, as cycloparaiiins of hydroaroe matic structure.

In accordance with the process of the invention, the hydrocarbon charge comprising a mixprises, for example, an enlarged chamber or a` tower packed with a suitable packing material through which the hydrocarbon charge is passed counter-current to a descending stream of the organo-metal halide complex. The extract phase is passed into a complex separating zone wherein hydrocarbons comprising the cycloparafiins are separated from the organo-metal halide complex. The cycloparafns eliminated from the complex separating zone are introduced into a product separating zone wherein separation of cycloparaflins into fractions predaminating in cycloparafiins of particular composition is effected. A part of the cycloparailins thus obtained is preferably recycled to the extraction zone and introduced therein at a point at, and preferably below, the point of introduction of the charge.

By maintaining suitable cycloparafiin isomerizing conditions within the extraction zone, comprising the introduction of hydrogen halide or assigns a material affording a hydrogen halide, and the maintenance of temperature conditions dened more fully below. the isomerization of cycloparamns such as. for example, the conversion oi cycloparaiilns of non-hydroaromatic structure to cycloparaiiins of hydroaromatic structure is accomplished simultaneously with the extraction operation.

When the extraction zone is maintained under cycloparaiiin isomerizing conditions, the raffinate phase eliminated therefrom and the cycloparafiins eliminated from the complex separating zone are passed in separate streams to separate stripping zones wherein the hydrogen halide admixed therewith is separated as gaseous fractions. The gaseous fractions comprising the hydrogen halide are recycled to the lower part of the extraction zone.

It is to be noted that in the process of the invention a. raffinate phase comprising open chain parailins and an extract phase comprising ,organo-metal halide complex in admixture with stream from the reaction zone and wherein hydrocarbons separated from catalyst drawn from the reaction zone are recombined with the total hydrocar on eilluence from the reaction zone before or d! ing product separation.

In order to set forth more clearly the nature of the invention it will be described herein in detail with reference to the attached drawing in which the single figure represents a more or less diagrammatic elevational view of one form of apparatus suitable for executing the process of the invention.

A hydrocarbon mixture comprising open chain paramns and cycloparaillns such as, for example, a naphthenic hexane fraction comprising open chain hexanes, methylcyclopentane and cyclohexane, is taken from an outside source and forced by means of pump i through line 2, containing suitable heating means such as an indirect heat exchanger 3, into an extraction zone. The extraction zone may comprise an elongated chamber or column 4 containing inert solid contact material such as, for example Raschig rings, crushedfbrick, silica stone, etc. The hydrocarbon charge is introduced into the column at an intermediate point along the length thereof.

A preformed fluid organo-metal halide complex is introduced into the top of the column by means of valved line Il. 'I'he iiuid organo-metal halide complex is preparedby mixing a metal halide of the Friedel-Crafts type, for example. a halide of aluminum such as aluminum chloride and/or aluminum bromide, with an organic compound vunder suitable conditions resulting in the interaction of the metal halide with the organic compound and/or decomposition products thereof. Suitable organic compounds with which the metal halide may be combined under conditions resulting in the obtaining of a desired organo-metal halide complex comprise, for example, aromatic hydrocarbons such as benzene. toluene; hydrocarbon fractions, such as an aromatic kerosene extract; cyclic oleflns, such as cyclohexene, cyclopentene, and alkyl derivatives thereof; ic

and olenic hydrocarbons of straight or branched chain structure; phenols; organic acids: ethers, etc. Of the suitable organo-metal halide comaseases y um operation. mecum uw mecum me' plexes. those comprising aluminum chloride-hydrocarbon complex are somewhat preferred.

By means of heat exchanger 8. and optionally heating or cooling means. such as closed coils l. 1 and l within column I. the hydrocarbons and complex are maintained in the temperature range of from about to about 140 C.. and preferably from about 20 C. to about 'l0' C. Atmospheric or superatmospheric pressures are maintained within column l. 'lhe pressure is. however, kept sumciently high to maintain the hydrocarbons in the liquid phase. Under these conditions cycloparaiilns. in the hydrocarbon mixture passing upward through the column, will be selectively removed from-open chain paramns resulting in the formation of a ramnate phase in the upper part of the column consisting essentially of paramnic hydrocarbons, and an extract phase in the lower part of the column consisting essentially of complex and cycioparaiiins.

The extract phase, comprising aluminum chloride-hydrocarbon complex and cycloparamns. is passed from the lower part of column 4 through valved line il, and heat exchanging means il, into a complex separating sone. The `complex separating sone may comprise a still i2. Within still I2, hydrocarbons comprising cycloparamns are distilled from the extract phase. vapors comprising methylcyclopentane and cyclohexane are passed from still i2 through line il and cooler Il into an accumulator I1. Cycloparailins may be removed fromy accumulator il through valved line 2| as a ilnal product. A -part of the cycloparaillns is. however. preferably passed through lines il, il and 2t into a fractionator 22. Within fractionator 22 a vapor fraction comprising methylcyclopentane is separated from a liquid fraction comprising cyclohexane. The llquid fraction is eliminated from fractionator 22 through valved line 2t as a ilnal product. The vapor fraction is eliminated from fractionator 22 through valved line 28. and a part thereof is preferably recycled through line 2i into extraction column l and introduced therein at a point below the introduction of the hydrocarbon charge. This. it has been found. aids materially in the separation of cycloparailins from paraillns under the operating conditions. A by-pass 25 is provided for the introduction of recycled methylcylopentane into charge line 2.

The ralnate phase comprising open chain hexanes is taken overhead from column l and passed through line 21 into accumulator 29.

Although separation oi' complex from the cycloparaillns contained in the extract phase is accomplished by distillation in the above illustrative description of the invention, other means of effecting the separation may be resorted to. Ihe complex may be separated from cycloparafiins by scrubbing the extract phase with a suitable hy drocarbon such as. for example, a low boiling saturated hydrocarbon, such as butane or pentane, as disclosed in copending application, Serial No. 538,893, nled June 6, 1944. y

A particular advantage of the invention resides in the ability to recover the naphthenic hydrocarbons of non-hydroaromatic structure, originally present in the charge, in the form of naphthenic hydrocarbons of hydroaromatic structure. 4 Thus, in the treatment of a naphthenic hexane fraction containing methylcyclopentane, maintenance of suitable cycloparatn isomerizing conditions within column 4 enables the conversion of 4the methylcyclopentane to cyclohexane during the extractsmperature within column l is maintained within the range of. for example. from about to about 14oc. ma pnrenbly from om 'zoto about C. A hydrogen halide promoter auch as. for example. hydrogen chloride. or a material affording the hydrogen halide under the conditions maintained in column I. is introduced into thelowerpartofthecolumnthroushvalvedline 0i at a point below the introduction of the charge. A part of the hydrogen halide may be introduced directly into charge line t from line l2. The hydrogen halide promoter is introduced at such a rate asto maintain a concentration of the hydrogen halide in the column in the range of from about 0.1 to about 2.0 and preferably from about 0.1toabout0percentby weightofthehydrocarbon in the column.

when thus maintaining cycloparaiiin lsomerising conditions within column I. the railinate phase passing through line 21. as well as the cycloparaffins emanating from still i2 through line il. will comprise hydrogen chloride. The hydrocarbons comprising hydrogen chloride within accumulator 2l are forced through line I8 into a stripping column 8|. Hydrocarbons comprising cycloparaffins containing hydrogen chloride are taken from accumulator i1. and forced through line II into a separate stripping column Il. Within stripping columns Il and Il conditions are maintained to effect the removal of the hydrogen chloride as a vapor overhead from the hydrocarbons. The hydrogen chloride thus separated in columns I4 and Il is passed therefrom through lines It, 32 and Il into column I. Make-up HCl is introduced into the system as required by means of valved line I1. Paraillnic hydrocarbons comprising open chain hexanes are eliminated from the lower part of stripping column 34, through valved line Il, as a nnal product. Cycloparailins comprising cyclohexane and unconverted methylcyclopentane are passed from stripping column l?, through valved `line 2l, into fractionator 22.

Although the above-detailed description of the invention has been directed to th'e treatment of a naphthenic hexane fraction, it is to be understood that the invention is in no wise limited to the treatment of this particular naphthenic hydrocarbon mixture and may be applied to any hydrocarbon mixture comprising open chain parafiins in admixture with cycloparailins. Thus, the invention may be applied with advantage to the treatment of naphthenic heptane fractions comprlsing dimethylcyclopentane, ethylcyciopentane. and methylcyclohexane, in addition to open chain heptanes, under conditions effecting separation of cycloparamns from parafllns, optionally with simultaneous conversion of the dimethylcyclopentane, and ethylcyclopentane to methylcyclohexane. T'he charge to the system need not necessarily comprise only hydrocarbons having substantially the same number of carbon atoms to the molecule, and hydrocarbon mixtures comprising cycloparail'ins and parsihns of relatively wide boiling range such as straight run naphthenic gasolines, straight run naphthenic naphthas, etc. may be charged directly to the system.

I-t is apparent from the foregoing that the invention obviates in a simple and a highly emcient manner the difilculties heretofore encountered in eecting the separation of cycloparafdns from paramns and enables the attainment of such separation with the simultaneous isomerization of the cycloparailins.

The following examples are indicative of the degree to which isomerization of cycloparafiins yis accomplished.v with simultaneous separation of cycloparafnns from admixture with open chain paraillns in accordance with the process of the invention.

Example I A methylcyclopentane concentrate having the following composition Per cent volume Methyl pentane 4.5 Normal hexane 40.0 Methylcyclopentane 55.0 Undetermined 0.5

was contacted in a single stage operation with an aluminum chloride-hydrocarbon complex under the following conditions:

Ratio of complex to hydrocarbon 2: 1 Timeof contact -minutes 30 Temperature C-.. 70

Hydrogen chloride was bubbled through the liquid throughout the operation to maintain a concentration of HC1 equal to 0.1% of the hydrocarbons charged. A raillnate phase and an extract phase were separately withdrawn. 'Ihe ratlinate phase contained 70% by volume of the hydrocarbons charged whereas the extract phase contained 30% of the hydrocarbons charged. A conversion of methylcyclopentane to cyclohexane of 40% was obtained. The degree of separation of cycloparamns from open chain parafnns is exemplified by the following ratios of naphthenes to paraillns:

Ratio of naphthenes to paraflins in charge 1.25

Ratio of naphthenes to paramns in rafllnate 1.06 Ratio of naphthenes to parafllns in extract 1.62

Example II i A methylcyclopentane concentrate having the following composition Per cent volume Methyl pentane 4.0 Normal hexane 37.0 Methylcyclopentane 51.0 Benzene .8.0

was contacted in a single stage operation with an aluminum chloride hydrocarbon complex under the following conditions.

Ratio of complex to hydrocarbon 1:1 'Iime of contact minutes 30 Temperature C 'l0 Ratio of naphthenes to paraillns in charge-- 1.24

Ratio of naphthenes to paraiflns in raftlnate 0.84

Ratio of naphthenes to paraillns in extract- 1.64

It is to be pointed out that the above examples are single stage extraction operations wherein the complex and hydrocarbons are contacted with one another in a single operation. After equilibrium is established the two phases are separated from each other and withdrawn from the contacting zone. As such they are indicative of the substantially complete separation of cycloparaillns from admixed open chain paraflins obtainable when operating in a multiple stage or continuous flow operation. It is also evident from the foregoing examples that high conversions of'the non-hydroaromatic cycloparaffin to hydroaromatic cycloparamn is accomplished during the execution of the process within the specined conditions.

Separation of the complex from the rafllnate, it has been found, may be facilitated by eiecting the separation in the presence of additionally introduced hydrogen halide into the still. A valved line 40 is therefore -provided enabling the passage of hydrogen chloride from line 32 into line I0 carrying the extract phase into still I 2. In a further modiilcation of the invention hydrogen halide, for example, h5 drogen chloride, is introduced into still l2 through line 40, but no hydrogen halide is introduced into column 4. Column 4 will then function as described above to eilect the separation of cycloparaillns from paraillns in the absence of any substantial cycloparailln isomerization, whereas in still i2 isomerization of cycloparaillns, for example, conversion of cycloparamns of non-hydroaromatic structure to cycloparamns. of hydroaromatic structure will take place. Under these conditions still I2 will function as a cycloparailln isomerlzing zone.

Aluminum chloride-hydrocarbon complex. substantially free of cycloparafllns, is eliminated from still I2 through valved line 4I and introduced into line 5, passing into the top of column 4.

Hydrocarbon mixtures comprising naphthenlc hydrocarbons often contain, in addition to open chain parailns, a certain amount of aromatic hydrocarbons. Thus, the naphthenic hexane and/or heptane fractions will generally comprise a certain amount of benzene and/or toluene. This material may be removed from the charge by suitable pretreatments prior to introduction into column 4. 'I'he aluminum chloride hydrocarbon complex, it has been found; however, is

far more selective as a solvent for aromatic hydrocarbons than for naphthenic hydrocarbons. Distillation of the extract under conditions effecting the separation of cycloparaillns from the complex will generally result in a retention in the complex of at least a substantial amount of the aromatics originally present in the charge. In a modification of the invention, when the charge to the system comprises aromatic hydrocarbons, at least a part of the complex eliminated from still I2 is passed through line 42, containing heat exchanging means 43, into a second distillation zone comprising, for example, still 44. Within still 44 the complex, substantially free of cycloparamns but still containing aromatic hydrocarbons, which in the treatment of naphthenic hexane fractions will comprise benzene, is subjected to more drastic distillation conditions to elect the separation of substantially all of the benzene. The more drastic conditions may be obtained by distillation ata higher temperature by means of heat input into heating means 08 and closed heating coil 4i, by prolonged residence assigns time in still Il; by use of subatmospherlc pressure. bythe introduction of stripping gases such as hydrogen, methane, ethane, nitrogen, ete., through valved line or HCl through line 50, or by any two or more of these expedients. Vapors comprising benzene are eliminated from still 44 through valved line 41. Aluminum chloridehydrocarbon complex, now tree oi' any substantial amount or benzene. is passed from still Il through valved line 4I, and is recycled at least in part through lines 49, 4I and 5 into the upper part ci column I.

The degree to which aromatic hydrocarbons can be separately recovered in the process oi the invention is exemplliied by the following example.

Example III The complex remaining after subjecting the extract phase in Example II to distillation at a temperature of 90 C. and atmospheric pressure to separate the extracted cycloparaiilns therefrom, was subjected to a second distillation in a separate zone at a temperature of '10 C., under a, subatmospheric pressure ci 150 mm. for a period of 3 hours. The resulting vapors were condensed and recovered. Upon analysis 33% by volume oi' the distillate was round to be aromatic hydrocarbon.

Example IV A hydrocarbon fraction boiling in the range oi from 65 C. to 85 C., containing normal hexane,

methylcyclopentane, cyclohexane and '1% by weight of benzene was contacted countercurrently in continuous operation with an AlCla hydrocarbon complex thereby forming a parailinic ramnate phase and an extract phase containing the complex, cycloparailins and benzene. The extract phase was stripped at 90 to 110 C. and aospheric pressure for 30 minutes to remove extracted cycloparafns therefrom. The remaining complex was thereafter subjected to further stripping, with the aid o! hydrogen chloride. at a temperature of 90 to 100 C. for a period of one hour. Properties of the distillate product from the second stripping operation indicated it to contain above 90% of benzene.

The separate removal oi the aromatics from the recycled complex is resorted to not only to. maintain the elciency of the aluminum chloride hydrocarbon complex as extracting medium and/or isomerization catalyst, but also, to separately recover the aromatic hydrocarbons originally present in the charge as a valuable byproduct of the process.

The invention as described is capable of modiiications without departing from the spirit and scope thereof. Thus, though a packed column has been chosen as a preferred extraction or extraction-isomerizing zone, other types of apparatus enabling intimate contact between the hydrocarbon charge and the organo-metal halide complex, resulting in the formation of an extract phase, and a raillnate phase may suitably be used. Thus, column 4 may be replaced by a plurality oi' chambers connected in series and provided with suitable stirring means, through which the hydrocarbon charge is passed, and in which operation ramnate may be removed from one or more of the chambers.

We claim as our invention:

l. The process for the production ot cyclohexane from' a hydrocarbon mixture comprising open chain hexanes and methylcyclopentane which comprises, subjecting said hydrocarbon mixture and a hydrocarbon-aluminum chloride complex to continuous countercurrent contact in the presence oi added hydrogen chloride in a contacting zone at a temperature o! from about '10 C. to about C. to eiect the conversion of methylcyclopentane to cyclohexane whiieiorming a raiilnate phase comprising open chain hexanes and an extract, phase comprising said complex, cyclohexane and unconverted methylcyclopentane, removing the raiiinate phase from one end of said contacting zone, separately removing said extract phase from the opposite end of said contacting zone, and separating cycloparaiilns comprising cyclohexane from said extract phase.A

2. The process for the production of cyclohexane from a hydrocarbon mixture comprising open chain hexanes and methylcyclopentane which comprises, subjecting said hydrocarbon mixture and a hydrocarbon-aluminum halide complex to continuous countercurrent contact in the presence of an added promoter affording a hydrogen halide in a contacting zone at a temperature or from about 30 C. to about 140 C. t0 eilect the conversion oi.' methylcyclopentane to cyclohexane while forming a raflinate phase comprising open chain hexanes and an extract phase comprising said complex, cyclohexane and unconverted methylcyclopentane, removing the raihnate phase from one end of said contacting zone, separately removing said extract phase from the opposite end ot said contacting zone, and separating cycloparains comprising cyclohexane from said extract phase.

3. The process for the production of cycloparaiilns or hydroaromatic structure from a hydrocarbon mixture comprising open chain parafiins and cycloparanins o! non-hydroaromatic structure which comprises, subjecting said hydrocarbon mixture and a hydrocarbon-aluminum halide complex to continuous countercurrent contact in the presence of an added hydrogen halide in a contacting zone at a temperature of from about-70 C. to about 100 C. to effect the conversion ot cycloparains of non-hydroaromatic structure to cycloparaflins of hydroaromatic structure while forming a raffinate phase comprising open chain paraillns and an extract phase comprising said complex and cycloparailins ot hydroaromatic structure, removing the rafnate phase from one end of said contacting zone, separately removing said extract phase from the opposite end of said contacting zone, and separating cycloparaiiins oi hydroaromatic structure from said extract phase.

4. The process for the production of cycloparaillns of hydroaromatic structure from a hydrocarbon mixture comprising open chain paraiiins and cycloparafdns of non-hydroaromatic structure which comprises, subjecting said hydrocarbon mixture and an organo-aluminum halide complex to continuous countercurrent contact in the presence of an added hydrogen halide in a contacting zone at a temperature of from about 30 C. to about 140 C. to effect the conversion of cycloparamns of non-hydroaromatic structure to cycloparamns of hydroaromatic structure while forming a raillnate phase comprising open chain paraillns and an extract phase comprising said complex and cycloparamns of hydroaromatic structure, removing the rafiinate phase from one end of said contacting zone, separately removing said extract phase from the opposite end of said contacting zone. and separating cycloparaiilns gtmdroaromatic structure from said extract 5. The process for the production of cycloparaiilns of hydroaromatic structure from a hydrocarbon mixture comprising open chain parailins and cycloparaillns oi' non-hydroaromatic structure which comprises, subjecting said hydrocarbon mixture and an organo-metal halide complex to continuous countercurrent contact in the presence ot an added promoter affording a hydrogen halide in a contacting zone at a temperature of from about 30 C. to about 140 C. to eiiect the conversion of cycloparaillns oi nonhydroaromatic structure to cycloparamns of hydroaromatic structure while forming a railinate phase comprising open chain paramns and an extract phase comprising said complex and cycloparaillns of hydroaromatic structure, separately removing the raiiinate phase and extract phase from said contacting zone, and separating cyclopara'lns of hydroaromatic structure trom said extract phase. A

6. The process for thei production of cycloparaiiins of hydroaromatic structure from a hydrocarbon mixture comprising open chain parafilns and cyclo of non-hydroaromatic structure which comprises, subjecting said hydrocarbon mixture and an organo-metal halide complex to continuous countercurrent contact in the presence of an added promoter affording a hydrogen halide in a contacting zone at cycloparailln isomerizing conditions to eilect the conversion of cyclo of non-hydroaromatic structure to cycloparatllns of hydroaromatic structure while forming a raiiinate phase comprisingopenchain r" andanextractphase comprising said complex and cycloparaiiins of hydroaromatic structure. separately removing the railinate phase and extract phase from said contacting zone, passing said extract phase into a complex separating zone, separating cycloparafiins of hydroaromatic structure from complex in said complex separating zone, and passing complex free oi any substantial amount of cycloparains from said complex separating zone to said contacting zone.

7. The process for the production of cyclohexane from a hydrocarbon mixture comprising open. chain hexanes and methylcyclopentane which comprises subjecting said hydrocarbon mixture and a hydrocarbon-aluminum halide complex to continuous countercurrent contact in the presence of an added hydrogen halide in a contacting zone at a temperature of from about '10 C. to about 100 C. to eilect the conversion of methylcyclopentane to cyclohexane while forming a raffinate phase comprising open chain yhexanes and hydrogen halide and an extract phase comprising said complex, cyclohexane, methylcyclopentane and hydrogen halide, passing the raiiinate phase from one end of said contacting zone into a stripping zone, said extract phase from the opposite end of said contacting zone into a complex separating zone, separating cycloparaiiins in admixture with hydroepesses structure which comprises, subjecting said hydrocarbon mixture and an organo-metal halide complex to continuous countercurrent contact in the presence of an added promoter affording a hydrogen halide in a contacting zo'ne at cycloparaiiin isomerlzing conditions to eil'ect the conversion of cycloparains of non-hydroaromatic structure to cycloparamns of hydroaromatic structure while forming a ramnate phase comprising open chain paramns and hydrogen halide and an extract phase comprising said complex, cycloparalns of hydroaromatic structure and hydrogen halide, passing said raillnate phase into a stripping zone, passing said extract phase to a complex separating zone, separating cycloparafilnsin admixture with hydrogen halide from complex in saidy complex separating zone, passing said cyclop in admixture with hydrogen halide from said complex separating zone to a separate stripping zone, separating a gaseous fraction comprising hydrogen halide in each oi said stripping zones, and passing said gaseous fractions from said stripping zones to said contacting zone.

9. The process for the production oi cyclohexane from a hydrocarbon mixture comprising open chain hexanes, niethylcyclopentane and "we, which comprises, subjecting said hydrocarbon mixture and a hydrocarbon-aluminum halide complex to continuous countercurrent contact in the presence of an added promoter afiording a hydrogen halide in a. contacting zone at a temperature of from about 70 C. to about 100 C. to eii'ect the conjrersion of methylcyclopentane to cyclohexane while forming a rafilnate phase comprising open chain hexanes and an extract phase comprising said complex, cyclohexane, methylcyclopentane and benzene, removing the raninate phase from one end of the contacting zone, separately removing the extract phase from the opposite end of the contacting zone, passing said extract phase into a first distillation zone, separating hydrocarbons comprising cyclohexane and methylcyclopentane as a vapor fraction from a liquid fraction .comprising complex containing benzene in said ilrst distillation zone, passing said liquid fraction into a second distillation zone, separating hydrocarbons comprising aromatic hydrocarbons as a vapor from a liquid fraction comprising complex in said second distillation zone, and recycling said liquid fraction comprising complex from said second distillation zone to said contacting zone.

l0. The process for the production ofv cycloof hydroaromatic structure from a hydrocarbon mixture comprising open chain paraiiins, cyclop of non-hydroaromatic struc- :ture and aromatic hydrocarbons, which comprises, subjecting said hydrocarbon mixture and an organo-metal halide complex tocontinuous countercurrent contact in the presence of an added promoter affording a hydrogen halide in a contacting zone at cycloparaln isomerizing conditions to eiect the conversion oi cycloparamns of non-hydroaromatic structure to cyclon of hvdroaromatic structure while forma ralnate phase comprising open chain parafilns'and an extract phase comprising said complex, cycloparamns and aromatic hydrocarbons, separately removing the railinate phase and extract phase from said contacting zone, passing.

said extract phase into a first distiliation zone, separating hydrocarbons comprising cycloparamns as a vapor fraction from a liquid fraction comprising complex containing aromatic hydrocarbons in said nrst distillation zone, passing said liquid fraction into a second distillation zone, separating hydrocarbons comprising aromatic hydrocarbons asa vapor from a liquid fraction comprising complex in said second distillation zone, and recycling said liquid fraction comprising complex from said second distillation zone to said contacting zone.

11. The process for the production oi' cyclohexane from a hydrocarbon mixture comprising Voperi chain hexanes and methylcyclopentane which comprises, subjecting said hydrocarbon mixture and a hydrocarbon-aluminum chloride complex to continuous countercurrent contact in a contacting zone at a temperature of from about C. to about '10 C. to form a raillnatey phase comprising open chain hexanes and an extract phase comprising said complex and methylcyclopentane, separately removing said ramnate and extract phases from the contacting zone, passing said extract phase and hydrogen chloride into a cycioparailin isomerizlng zone maintained at cycloparamn isomerizing conditions, thereby eilecting the conversion of methylcyclopentane to cyclohexane, and separately withdrawing hydrocarbons comprising cyclohexane and complex from said isomerizing zone.

i2. The process for the production oi cyclohexane from a hydrocarbon mixture comprising open chain hexanes and methylcyclopentane which comprises, subjecting said hydrocarbon mixture and an organo-aluminum halide complex toy continuous countercurrent contact in a contacting zone at a temperature of from about 20 C. to about 70 C. to form a railnate phase comprising open chain hexanes and an extract phase comprising said complex and methylcyclopentane, separately removing said raillnate and extract phases from the contacting zone, passing said extract phase and a hydrogen halide into a cycloparaiiin isomerizing zone maintained at cyclopar isomerizing conditions, thereby effecting the conversion of methylcyclopentane to cyclohexane, and separately withdrawing hydrocarbons comprising cyclohexane and complex from said lisomer-izing zone.

i3. The process for the production -oi' cycloparafiins oi' hydroaromatie structure from a hydrocarbon mixture comprising open chain paraffins and cycloparaiiins of non-hydroaromatic structure which comprises, subjecting said hydrocarbon mixture and a hydrocarbon-aluminum halide complex to continuous countercurrent contact in a contacting zone at a temperature of from about 20 C. t0 about 140 C. to form a raftinate phase comprising open chain parafiins and an extract phase comprising said complex and cycloparaiiins of non-hydroaromatic structure, separately removing said rafllnate phase and said extract phase from the contacting zone, passing said extract phase and a hydrogen halide into a paraflins of hydroaromatic structure from a hy drocarbon mixture comprising open chain parafilns and cycloparamns of non-hydroaromatic structure which comprises, subjecting said hydrocarbon mixture and a hydrocarbon-aluminum halide complex to continuous countercurrent contact in a contacting zone to form a ramnate phase comprising open chain parafilns 'and an extract phase comprising said complex and cycloparafiins of non-hydroaromatic structure. separately removing said raillnate phase and said extract phase from the contacting zone and subjecting said extract phase in the presence of an added hydrogen halide to cycloparailln isomerizing conditions thereby effecting the conversion of cycloparaillns of non-hydroaromatic structure to cyclo.. paraillns of hydroaromatic structure.

15. 'I'he process for the production of cycloparalns from a hydrocarbon mixture comprising cycloparaffins in admixture with open chain parailins and aromatic hydrocarbons which comprises, subjecting said hydrocarbon mixture and an organo-metal halide complex to continuous countercurrent contact in a contacting zone at a temperature of from about 20 C. to about 140 C. to form a ralnate phase comprising open chain paramns and an extract phase comprising said complex, cycloparafiins and aromatic hydrocarbons, removing the raillnate phase from one end of said contacting zone, separately removing said extract phase from the opposite end of said contacting zone, passing said extract phase into a rst distillation zone, separating hydrocarbons comprising cycloparailins as a vapor fraction from a liquid fraction comprising complex containing aromatic hydrocarbons in said iirst distillation zone, passing said liquid fraction into a second distillation zone, separating hydrocarbons comprising aromatic hydrocarbons as a vapor from a liquid fraction comprising complex in said second distillation zone, and recycling said liquid iraction comprising complex from said second distillation zone to said contacting zone.

16. The process for the separation of cycloparafflns from a hydrocarbon mixture comprising an isomerizable cycloparamn having at least six carbon atoms to the molecule and containing at least five carbon atoms in the ring in admixture with openv chain parailins while simultaneously isomerizing said cycloparain, which comprises subjecting said hydrocarbon mixture and a hydrocarbon aluminum chloride complex to continuous counter current contact in the presence of an added promoter aiording a hydrogen halide in a contacting zone at a temperature of from about 30 C. to about 140 C., thereby eilecting the isomerization of said cycloparailin having atleast six carbon atoms to the molecule and containing at least ve carbon atoms in the ring to a cycloparailin having at least six carbon atoms to the molecule and containing at least ilve carbon atoms in the ring while forming a raillnate phase comprising open chain paramns and an extract phase comprising said complex and isomerized cycloparamn, separately removing the ramnate phase from one end oi.' said contacting zone. separately removing said extract phase from the opposite end of said contacting zone, and separating said isomerized cycloparafiin from said extract phase.

17. 'I'he process for the separation of cycloparamns from a hydrocarbon mixture comprising an isomerizable cycloparain having at least six carbon atoms to the molecule and containing atleast nve carbon atoms in the ring in admixture with open chain paraflins, which comprises subjecting said hydrocarbon mixture and an organometal halide complex to continuous counter current contact in the presence of an added 8 @seams promoter aifording s hydrogen halide in a contacting zone at cycloparaiiin isomerizing conditions to eect the isomerization oi' said isomerizsble cycloparaiiin having at least six carbon stoms to the molecule and at least five carbon atoms in the yring to s cycloparamn having at least six carbon atoms to the molecule and at least' iive carbon atoms in the ring while formlng a raiiinate phase comprising open chain paramns, and an extract phase containing said complex and cycloparamns comprising said isomerized cycloparammsepnratehr removing the ramnate phase and extract phase from said con-- tacting zone, and separating cycioparatilns com- -prising said isomerized cycloparamn from said extract phase.

WILLIAM E. ROSS. PHILIP PEZZAGLIA.

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