DE2356473A1 - PROCESS FOR CONVERSION OF HYDROCARBONS - Google Patents

Description

Dr.-Ing. E. BERKENFELD · Dspf.-lng. H. B ER KS N FE LD, patent attorneys, Cologne System . File number

for entry from November 9th 1973 vA / name d. Note: The Lummus Company

Process for converting hydrocarbons

The present invention "relates to an improved method according to Friedel-Crafts for the catalytic conversion or processing of hydrocarbons using a noble metal of Group VIII containing catalyst on a refractory Oxide and an aluminum halide is supported, in which the aluminum halide portion of the catalyst in situ during the Process is formed and then its union with the other components of the catalyst is effected »According to this point of view the invention relates to the use of catalysts the Friedel-Crafts type for processes, for which catalysts have not yet been used «.

According to the Friedel-Crafts reaction, the conversion of hydrocarbons is accelerated by the use of a catalyst containing an aluminum halide, usually aluminum chloride or aluminum bromide with acyl halides in the presence of aluminum chlorides From 1950 to 1940, especially during the Second World War, processes of this type were extensively researched and it was predominantly the large petroleum companies who carried out this process with the catalyst system. The research aimed in particular to the application of such process for the production of gasoline, normal to the Isomerization paraffins to branched chain paraffins, as well as aromatic alkylation and paraffinic compounds having 01efinen _o To a lesser extent was the work to other methods, for example the isomerization of cycloparaffins _o Formerly aluminum chloride was used for the catalytic cracking process. «The original work between 1930 and 1940 concerned the testing of Friedel-Crafts catalysts, which only contained aluminum halide; Then supported aluminum halides were investigated «, Further development led to the research of catalysts,

the aluminum halides with free aluminum, double salts of aluminum halides, aluminum halides with additives and aluminum halide-organic complexes. Some patents relate only aluminum halides or mixtures of aluminum halides with free aluminum, wherein the aluminum halide is formed in situ in the hydrocarbon conversion zone by reaction of metallic aluminum and a halogen or Halogenidwasserstoff, which is supplied separately or in a mixture with the feed _e work in this area were but apparently not taken very far, with the exception of the alkylation of paraffinic hydrocarbons with olefins. Most of the literature shows that the aluminum halide catalyst was introduced into the reaction Process for the production of supported aluminum halide catalysts by improved impregnation, in particular by sublimation of aluminum halides into the pores of the support _{or the like}

As a result of this work, interest in its use grew of Group VIII noble metal catalysts with added halogen for hydrocarbon conversion.

Recently, catalysts comprising a Group VIII noble metal supported on alumina have been proposed which is impregnated both with added halogen, such as hydrogen halide, as well as with an aluminum halide. The aluminum halide component is generally in vapor form into the catalyst by sublimation and impregnation of the sublimed vapors introduced into the pores of the support,

The present invention is based on the object of an improved Forming a catalyst comprising a Group VIII noble metal, a support and an aluminum halide for the purpose of producing hydrocarbons to convert.

The invention is also based on the object of an improved Process for converting hydrocarbons using

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to train such a catalyst,

Another object of the present invention is an improved method for preparing such a catalyst

The invention relates, generally speaking ^ a process for the conversion of hydrocarbons _p in which the hydrocarbon with a noble metal of group VIII and a Aluml wirdj brought = niumhalogenid containing catalyst into contact which is carried on a refractory oxide ₉ wherein the catalyst in the hydrocarbon conversion zone is prepared in situ by the continued contact of the aluminum with a halogenating agent to form the aluminum halide, and in which the aluminum halide so formed combines with a catalyst ₃ comprising a Group VIII noble metal and supported on a refractory oxide _e

The invention also relates to a method zur.in situ formation of a supported catalyst ₉ comprising a noble metal of group VIII and an aluminum halide? in which aluminum halide is continuously brought into contact with a halogenating agent to produce an aluminum halide and the aluminum halide thus produced is continuously added to a catalyst bed comprising a Group VIII noble metal supported on a refractory oxide

The invention is described in more detail below with reference to the drawing where the figures have the following meaning

Fig. 1 is a flow sheet ₉ illustrating the implementation of a hydrocarbon conversion according to the invention

Fig. 2 is a flow diagram showing the manufacture of a fuel for jet engines according to the present invention;

Fig. 3 shows the arrangement of the catalyst components in the reactor j, in which a layer «s? k metallic aluminum

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nium is on top of a fixed bed having a noble metal catalyst supported on a refractory oxide;

Fig. 4 illustrates another arrangement of the catalyst in the reactor in which the aluminum metal with the worn precious metal component is mixed; and

Fig. 5 shows an arrangement of the catalyst g corresponding to FIG. 3, but in which the hydrocarbon feed is so initiated · that they are 4 on the aluminum metal layer passes by.

The invention can be used to convert a number of hydrocarbons or used for finishing processes. Examples of such procedures are:

Conversion of normal paraffins into isoparaffins, Alkylation of paraffins with olefins,

Production of alkyl aromatic compounds from aromatic compounds Compounds and olefins,

Isomerization of alkyl aromatic compounds, such as xylene,

Transalkylation-disproportionation of aromatic hydrocarbons, such as the production of benzene and xylenes from toluene;

Production of a fuel for jet engines through the combination of hydrogenation and hydroisomerization,

Hydrocracking of heavy hydrocarbons and hydrogenation of hydrocarbons.

The process of the invention is generally carried out using as a feed a hydrocarbon and a halogenating agent such as a hydrogen halide, a halogen oder.a mixture of these leads into a reaction zone which contains metallic aluminum and a catalyst bed which is a

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Precious metal of group VIII contains that of a refractory = fairies Oxide is worn. Hydrogen can also be introduced into the reaction zone, in considerable amounts, in order to Take part in the main reaction, such as a hydrogenation, or in small quantities to prevent the formation of undesired by-products if necessary to prevent. The aluminum metal reacts with the halogenating agent to form the corresponding aluminum halide brought into contact. The aluminum halide then continuously combines physically with the precious metal being worn. tall catalyst to form a supported catalyst comprising noble metal and aluminum halide. This in the reaction zone in situ formation of the aluminum halide component results in a constant supply of freshly formed aluminum halide catalyst, ββ · which allows the implementation for a considerable period of time with a practically uniform Speed runs.

1 shows a general flow diagram for carrying out various processes with the exception of the production of fuel for jet engines, for the production of which the process illustrated in FIG. 2 is preferred. The hydrocarbon feed is fed through line 1. Liquid recycle can be added through line 8 and this liquid stream including a reflux is passed into reactor 10 through line 3. A halogenating agent, for example a hydrogen halide such as hydrogen chloride, is either added to the feed in line 2 or separately fed into the reactor through line 4 - see FIG. 5. Hydrogen can be added to the reactor through either line 5 or 5A if required by the process. The resulting as the process product ^ Kohlenwassexä "ff _t ,, is withdrawn from the lower part of the reactor through line 6 and preferably cooled in a heat exchanger 12; Excess halogenating agent can be removed in the scrubber 14 by alkali. The reaction products are removed through line 7 and sent to a fractionation device not shown in the drawing. Unreacted or partially reacted hydrocarbons can be released from the process product

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th separated and through line 8 to merge with the for fed back to the reactor 10.

Fig. 3 of the drawing shows the arrangement of the catalyst components within the reactor. The trains through line 3 led, yes, · containing hydrocarbons and halogenating agents. Feed enters the top of the reactor through inlet 36 and flows through gas distributor 30 into a layer of aluminum metal 32, conveniently in the form of pellets. The halogenating agent contained in the feed reacts with the aluminum metal to form aluminum halide, which with the feed flows downwardly into packed bed 34 which contains a Group VIII noble metal such as platinum as a catalyst supported on a refractory oxide such as alumina. The hydrocarbon then reacts with the supported aluminum halide noble metal catalyst to form the desired products which can be withdrawn through line 6. If hydrogen is used, this can either be added to the feed through line 5 or a? are passed through line 5k in countercurrent to the feed to the reactor. Excess hydrogen is removed through line 9, which can also serve to discharge other gaseous substances from the reactor.

Figure 4 illustrates another arrangement of a catalyst system in accordance with the present invention in which no particular aluminum metal bed is present 32 is present, but the aluminum pellets are distributed in the fixed bed of the supported noble metal catalyst. The aluminum cladding formed in the bed continues to mix into the catalyst system. It has been found that in some cases the system illustrated in FIG 3 is preferred as it tends to have less cracking that comes from some of the feeds in direct contact with it may come from pure aluminum halide before the feed reaches the fixed bed 34 of the catalyst.

Fig. 5 shows a preferred embodiment for certain methods, in which the cracking is even further reduced. Ge

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According to this figure, the hydrocarbon feed passes through an inlet 40 -in one located in the upper part of the reactor Room 42 a. The aluminum rail 32 is covered by a plate, has the passages 44 which extend through the aluminum layer into the fixed bed 34 of the noble metal-alumina catalyst. The hydrocarbon feed is directed into fixed bed 34 through guides 44 and bypasses the aluminum layer 32. In this embodiment of the invention, the halogenating agent is not mixed with the charge prior to entering the Reactor mixed, but passed from line 4 through inlet 45 directly into layer 32 of the aluminum metal; the Halogenating agent flows downwardly in the fixed bed 34 of the supported noble metal catalyst and mixes with it. In this way the hydrocarbon feed does not come into contact with freshly formed aluminum halide.

The aluminum halide formed during the course of the process can be any aluminum halide used as Friedel-Crafts catalyst is suitable, such as aluminum chloride, aluminum bromide and mixed chloride-fluorides and other mixed halides of aluminum. Aluminum chloride is the preferred compound. The aluminum metal can be in any suitable form can be used, for example, as powder, pellets or granules; it is generally used in an amount based on the total Catalyst charge, from 1 to 5 weight percent used.

The aluminum halide is formed by reacting the aluminum with a halogenating agent which can be a hydrogen halide, a free halogen, or a mixture of these. Particularly Hydrogen chloride, hydrogen bromide, chlorine, bromine (in the vaporous state) and mixtures of hydrogen chloride with are suitable Chlorine and hydrogen bromide with bromine. The preferred halogenating agents are the hydrogen halides, especially hydrogen chloride. The use of a hydrogen halide has in comparison. at least two advantages over a free halogen. By implementing of the hydrogen halide with the aluminum is formed hydrogen, which is used as a reactant, for example, for the production of fuel for jet engines or to prevent

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tion of the formation of undesired by-products can serve. Secondly the catalyst support does not need to be impregnated with halogen, as is usually done, since everyone is responsible for the reaction with the aluminum unnecessary excess of hydrogen halide serves as a substitute for the impregnation, whereby the catalyst efficiency can be promoted for many processes. The halogenating agent is added to the system as it is necessary to maintain catalyst efficiency and it is generally in the ppm range based on fresh loading, required.

The noble metal components of the group VIII catalyst, i.e. the platinum group, include platinum, palladium, ruthenium, Rhodium, osmium and iridium in question. Platinum and palladium are the preferred metals. The refractory oxide is a solid and may consist of several different oxides that are not necessarily equivalent carriers. To the appropriate refractory oxides frozen various substances, such as aluminum H & xide, Titanium oxide, zirconium oxide, chromium oxide, zinc oxide, silicon oxide-aluminum oxide, Chromia-alumina, alumina-boron oxide, silica-zirconia and various others of course occurring refractory oxides such as bauxite.

The Group VIII noble metal is incorporated into the carrier in any suitable known manner; in the present Case the catalyst is in the elemental state.

The preferred catalyst system for use in the invention Process has platinum, supported on aluminum oxide, the aluminum chloride is added, -eer in situ by the reaction is formed by aluminum with hydrogen chloride.

The in situ formation of aluminum halide is advantageous 4 «to carry a number of hydrocarbon conversion process, as already indicated above. In the following some methods are described for which the invention applies can be turned.

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Isomerization of η-paraffins -

The invention is useful for isomerizing normal C, -Cg or higher paraffins to the corresponding branched-chain paraffins for example for the conversion of butane to isobutane, of n-pentane = fe to isopentane or neopentane and of η-hexane to various isohexanes, such as methylpentanes and / or dimethylbutanes. The process product is an equilibrium mixture normal and branched chain paraffins. In the case of a method carried out according to FIG. 4, there is a considerable reduction / of By-products that / by -ee the borrowed The hydrocarbon feed comes into contact with the aluminum pellets 32 layer as shown in FIG. The implementation of the Process according to the invention according to the scheme in FIG. 5 leads to an even greater decrease in the cracking produced By-products, since no aluminum halide is freshly formed, which immediately after formation with the hydrocarbon in Contact comes while some aluminum halide is present in the embodiments of the method according to FIGS. 3 or 4 can"

These isomerizations can be carried out in the presence of hydrogen v / ground and so both cracking and the formation of undesirable by-products are reduced. The hydrogen is preferably fed / with the feed, but it can also be fed countercurrently into the lower part of the reactor will. . . ·

These isomerization reactions are generally carried out at temperatures from about 38 ° C to about 232 ° C, preferably between about 65j5 ° and 121 ° C, at pressures in the range from about 14.0 kg / cm to about 70.0 kg / cm. The application a pure feed which contains only a paraffin is not necessary, the process can also be used for isomerization of the paraffins present in a mixed feed.

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Isomerization of Cp aromatics

The process of the present invention can also be used for the preparation of equal weight mixtures of xylenes from m-xylene containing Feeds or from a non-equilibrium mixture of isomers. Xylenes, which are low in a desired isomer, serve. The method of the invention can in particular also serve to produce pure m-xylene or a non-equilibrium mixture of isomeric xylenes, which have a low content of the desired form, «a mixtures of xylenes with a high content of the o- or p-shape.

Such a process is generally carried out at one temperature in the range from about 121 ° to about 353 ° C and at pressures in the

p Ο

ranging from about 7.0 kg / cm to about 46.0 kg / cm. The presence of hydrogen is not required for this process, since under these conditions a low or no cracking occurs at all. For the same reason, any of those illustrated in FIGS. 3 to 5 can also be used Procedure form can be selected.

Alkylation of paraffins and aromatics with olefins

The method of the invention is also useful for manufacture of long chain paraffinic compounds by alkylating an isoparaffin such as isobutane with an olefin such as Ethylene, propylene or butylene. The olefin to be used can be one of the abovementioned compounds in pure form, or but also exist as a mixture of such olefins, or a mixture of such olefins with the saturated isomer. aside from that can use longer-chain olefins or paraffins, as is common practice Alkylation process is the case. Such Processes are carried out at temperatures in the range from about 38 ° to about 232 ° C., preferably in the range from 6 ° to about 149 ° C.

The process can also be used for the production of linear alkylben-

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zolen serve, in which the alkyl side chain 2 to 16 or contains more carbon atoms, as well as for the production of Alkylnqtithalinen or other alkyl aromatic compounds. aside from that can aromatic compounds ^ the substituents such as hydroxy, amino, nitro, 'halogen etc on the aromatic ring contain, be alkylated, ■ to produce, for example, alkylphenols. Hydrogen is generally not required for these alkylation reactions «

Production of fuel for jet engines from kerosene fractions. . "

An important new application of the method of the present invention lies in the ■ production of high quality fuel for DUsentriebwerke from a kerosene fraction and also those fuels that are used for conventional or supersonic aircraft »The current specifications for fuel for jet gears in supersonic aircraft require a gripping point of less than below -49 ° C _? a Luminometerzahl (ASTM Designation D-1322-54T) of at least 79 or a "smoke point" of at least 35. For such fuels is also a low content of aromatics, preferably less than 1 ₉ 0 v, ~%, is required. These fuels also require high thermal stability and a high caloric value & few kerosene fractions are suitable for normal fuels for jet engines without further treatment? most of them need \ to be improved. Various processes have been developed to produce fuel for jet engines from kerosene fractions by isomerization and / or hydrogenation and / or hydrocracking Isomerization and a subsequent hydrogenation of a petroleum distillate are known.

It has been found that according to the method of the present invention by using a catalyst which is one of a refractory oxide comprises noble metal carried and an aluminum halide, the aluminum halide being formed in situ,

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Fuels for jet engines, including those for use in supersonic aircraft, made from a petroleum fraction or mixtures of hydrocarbons that boil in the kerosene range, can be prepared by a one-step process that combines hydroisomerization and hydrogenation.

The term “kerosene fraction” is understood to mean a hydrocarbon fraction boiling up to 288 ° C as the end point with an initial boiling point which is sufficiently high to result in a flash point of at least 37.8 ° C. This fraction may or? Onaaeru.r by a suitable hydrocarbon conversion such as hydrocracking, catalytic cracking,} &. TFSS E'6 ^r '> an immediately distilled from Fe ^ oil distillate> the viscosity or the like have been obtained £. The kerosene fraction. must be desulphurized before treatment in practically all cases, since sulfur reacts with the aluminum halide part of the catalyst and destroys it.

FIG. 2 shows a flow diagram similar to the flow diagram in FIG. 1, but for the production of fuel for jet engines is modified. In line 1 there is a hydrocarbon feed mixed with a reflux from line 8 and the combined streams flow through line 3 into the reactor 10. Depending on the origin of the load, preheating can be carried out of the combined stream in line 3 may be required to bring this to the reaction temperature of 121.1 ° to 232 ° C., preferably 149 to 204 ° C, bring what is expedient by. the heat exchanger 12 by heat exchange with process products or in any other desired manner. A halogenating agent, such as hydrogen halide, is preferably mixed with the feed in line 2 after preheating or optionally separately into the reactor introduced through line 4. That containing the feed, the reflux and in most cases the halogenating agent Electricity is introduced into the top of the reactor 10.

In the reactor normal paraffins are isomerized to isoparaffins under a hydrogen pressure, and unsaturated compounds,

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for example aromatic and olefinic, become the corresponding saturated compounds, namely naphthalenes and paraffins, especially isoparaffins, hydrogenated. Compared to most of the other processes discussed above require that used to make fuel for jet engines Process considerable amounts of hydrogen. Even when a hydrogen halide is used as a halogenating agent, the hydrogen evolved by the reaction between the hydrogen halide and aluminum is not sufficient for hydrogenation to achieve the desired degree. As a result, additional hydrogen must be supplied, which is preferred takes place in the lower part of the reactor through line 5A, which then flows in countercurrent with the hydrocarbon and with this comes into contact.

Liquid products are withdrawn from the lower part of the reactor through line 6 and cooled in heat exchanger 12. As indicated above, the heat exchanger can also be used to preheat the feed intended for the reactor.

Gaseous products, including vaporized hydrocarbons, Excess hydrogen and halogenating agent are removed from an upper part of the reactor through line 9, cooled in the heat exchanger 16 and in the separator 18 in a liquid, hydrocarbon-containing product and in separated a gaseous product mainly containing hydrogen and halogenating agents. The liquid product will recycled through line 8 to the reactor feed. The gaseous products are through line 10 to a scrubber 20 and then passed through line 13 into the atmosphere and / or through line 11 as waste

taken from ,,

It is a further advantage of the method of the present invention that this can be carried out under relatively mild conditions in terms of temperature and pressure. the Inlet temperature is between about 121 ° and about 204 °, preferably between about 149 ° and about 204 ° C. The temperature in the

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Reactor fluctuates between about 121 ° and about 316 ° C, preferably between about 177 ° and about 260 ° C; the pressure is in the range from about 21.1 to 84.4 kg / cm ² , preferably between about 28.0 to 70.0 kg / cm 2. A considerable cooling effect and a temperature control resulting therefrom is achieved by dissipating the heat of reaction by considerable heating of both the liquids and the gases in the reactor and by evaporation of liquid, finally also by the introduction of "cold" hydrogen without preheating into the Reached the reactor. The ratio of the reflux to the fresh charge is about 0.05 fei »1.00, preferably 0.10 fei ¥ 0.50.

When the method of the present invention is used to make fuel for jet engines, it is not disadvantageous to use the reactor-catalyst system shown in FIG. 3, in which the feed is freshly formed Touched aluminum halide. Any cracking that occurs as a result of this contact leads to the formation of additional isoparaffins, which are favorable for the quality of the products. The temperature control involved in the process prevents fie occurrence of reactions leading to the formation of undesirable cracking by-products such as coke.

EXAMPLE

A liquid jet engine kerosene fraction was first saturated with hydrogen chloride by passing a stream of dry HCl gas through it. The HCl concentration in the feed was 5360 ppm. The mixture was preheated, mixed with make-up hydrogen, heated to the inlet temperature of 115 to 123.3 ° C, and introduced into the reactor. The reactor was operated at a temperature of 200 to 201 C and a pressure of ~ 55 _% 2. kg / cm and a flow rate (LHSV) of 0.7.

An examination of the feed and the product revealed an essential one Improvement for use in supersonic aircraft as shown by the following data:

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Loading product

Aromatics, VoI.-Ji (ASTM D-1319) 16.5 1.0. Freezing point ⁰ C (ASTM B-2386) - & ?, ⁶ ~ S3, 9 '

"Smoke point" (estimated) 21.5. '36 _S 3

The "smoke point" was estimated on the basis of the well-known relationships between the "smoke point ^83" and the aromatic content. The combination of a very low aromatic content, low freezing point and high "smoke point" meet more than the specifications available for fuels for supersonic aircraft,

The process of the invention is also suitable for other hydrocarbon conversion processes ₉ in which catalysts of this type are advantageous, and also for special applications not described above «,

Patent claims:

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Claims (32)

D r.-1 ng. E. BERKENFELD ■ D ^: pl.-lrg. H. BERKENFELD, patent attorneys, Cologne g act indications Entry from November 9th 1973 vA / Named. Note: The Lummus Company PATENT CLAIMS
ι 4Process for the conversion of hydrocarbons by treatment of the hydrocarbon with a catalyst comprising an aluminum halide and a Group VIII noble metal, which is supported by a refractory oxide, characterized, that one continuously forms the aluminum chloride in situ in the hydrocarbon conversion zone by that Aluminum reacts with a halogenating agent such as a hydrogen halide, halogen or a mixture of these, and mandas characterized in that aluminum halide formed in this way is continuously added to a bed of a Group VIII noble metal catalyst, that of a refractory Oxide is worn. 2. The method according to claim 1, characterized in that the conversion is carried out in the presence of hydrogen. 3. The method according to claim 1, characterized in that the aluminum is arranged in a layer above the bed. A method according to claim 1, characterized in that the aluminum in the bed is composed of a mixture with a noble metal Group VIII is present as a catalyst supported on a refractory oxide. 5. The method according to claim 1, characterized in that the Halogenating agent is mixed with the hydrocarbon prior to its introduction into the reaction zone. 6. The method according to claim 1, characterized in that the halogenating agent is a hydrogen halide _o 7. The method according to claim 1, characterized in that the 409821/1189 Aluminum halide is aluminum chloride. 8. The method according to claim 1, characterized in that the Precious metal is platinum. 9. The method according to claim 9, characterized in that the Refractory oxide is alumina. 10. The method according to claim 3, characterized in that the Hydrocarbon is introduced into the reaction zone at a point below the aluminum layer and thereby the halogenating agent is introduced separately into the aluminum layer. - 11. The method according to claim 1, characterized in that a normal paraffin is converted to an isoparaffin by isomerization. 12. The method according to claim 1, characterized in that the conversion is an alkylation of a paraffin with an olefin is. 13. The method according to claim 1, characterized in that the Conversion involving the alkylation of an aromatic compound is an olefin. 14. Verfaheren according to claim 1, characterized in that the conversion is an isomerization of an aromatic hydrocarbon. is hydrogen with eight carbon atoms. 15. The method according to claim 14, characterized in that one a mixture of isomeric xylenes isomerized. 16. The method according to claim 1, characterized in that one a mixture of hydrocarbons boiling in the kerosene boiling range converted into a fuel for jet engines. 40 98 21/1 189 17. A method for producing a fuel for jet engines from a boiling in the kerosene range mixture of hydrocarbons according to claim 1, characterized in that waiting the mixture of hydrocarbons in the opposite _T bringing of a catalyst into contact with a noble metal from the Group VIII supported on a refractory oxide and an aluminum halide on v / eist, the aluminum halide being formed in situ by the reaction of aluminum with a halogenating agent such as a hydrogen halide, halogen or a mixture thereof. 18. The method according to claim 17, characterized in that the halogenating agent is a hydrogen halide. 19. The method according to claim 17, characterized in that the Aluminum halide is aluminum chloride. 20. The method according to claim 17, characterized in that the noble metal is platinum. 21. The method according to claim 17, characterized in that the aluminum in a layer above the bed of the noble metal catalyst, which lies on a refractory oxide, is arranged. 22. The method according to claim 17, characterized in that the refractory oxide is aluminum oxide. 23. The method according to claim 17, characterized in that the reaction temperature is kept at 121 to 316 ° C. 24. The method according to claim 17, characterized in that the Hydrogen is introduced in countercurrent to the mixture of hydrocarbons. 25. The method according to claim 17, characterized by the further method steps ϊ 409821/1188 (a) Deriving from the hydrocarbon conversion reaction escaping gas; (b) Separation of this gas outflow into a liquid and a vapor phase and (c) Recycling the liquid phase to the hydrocarbon Conversion reaction. 26. The method according to claim 25, characterized in that the ratio of the recirculated liquid to fresh charge is about 0.05 to 1.00. 27. A method for the in situ formation of a catalyst according to claim 1, which comprises a noble metal from group VIII, a refractory oxide and an aluminum halide, characterized in that that continuously aluminum with a halogenating agent such as a hydrogen halide, a halogen or a mixture of these to form an aluminum halide and the aluminum halide so formed continuously fed to a Group VIII noble metal bed supported on a refractory oxide. 28. The method according to claim 27 _9, characterized in that the aluminum halide is aluminum chloride *. 29. The method according to claim 27 »characterized in that the Aluminum placed in a layer above the bed of the Group VIII noble metal resting on a refractory oxide is. 30. The method according to claim 27, characterized in that the aluminum in the bed as a mixture of the noble metal catalyst Group VIII supported on a refractory oxide. 31. The method according to claim 27, characterized in that the halogenating agent is a hydrogen halide. 409821/1189 32. The method according to claim 27, characterized in that the refractory oxide is aluminum oxide. 409821/1189 ι ^W * Blank page