KR20010108493A - Method for hydrogenating non-substituted or alkyl-substituted aromatic compounds while using a catalysts having macropores - Google Patents

Abstract

The invention relates to a method for hydrogenating at least one mononuclear or polynuclear aromatic compound which is non-substituted or which is substituted with at least one alkyl group by bringing the at least one aromatic compound into contact with a gas containing hydrogen in the presence of a catalyst. Said catalyst comprises, as an active metal, at least one metal of subgroup VIII of the periodic table that is applied to a support. The invention is characterized in that the support comprises macropores.

Description

METHOD FOR HYDROGENATING NON-SUBSTITUTED OR ALKYL-SUBSTITUTED AROMATIC COMPOUNDS WHILE USING A CATALYSTS HAVING MACROPORES}

There are many methods for hydrogenating benzene to cyclohexane. These hydrogenation processes are mainly carried out in gaseous or liquid phase on nickel catalysts and platinum catalysts (see eg US 3 597 489, US 2 898 387 and GB 799 396). Typically, most of the benzene is first hydrogenated to cyclohexane in the main reactor and then the conversion to cyclohexane in one or more secondary reactors is completed.

Strong exothermic hydrogenation reactions require careful control of temperature and residence time in order to achieve complete conversion under high selectivity. In particular, there is a need to suppress any significant formation of methylcyclopentane that occurs at relatively high temperatures. Typical cyclohexane statements should have a residual benzene content of <100 ppm and a methylcyclopentane content of <200 ppm. In addition, the content of n-paraffins (n-hexane, n-pentane, etc.) is also important. Most of these unwanted compounds are also formed at relatively high hydrogenation temperatures and can be separated from the cyclohexane product only by complex separation operations (extraction, rectification, or the use of molecular sieves as described in GB 1 341 057), such as methylcyclopentane. have. In addition, the catalyst used for hydrogenation has a strong influence on the content of unwanted methylcyclohexane formation.

In view of this background, hydrogenation is preferably carried out at the lowest possible temperature. However, this is limited by the fact that, depending on the type of hydrogenation catalyst used, the hydrogenation activity of the catalyst which is high enough to achieve economic space-time yield is only achieved at relatively high temperatures.

Nickel and platinum catalysts used in the hydrogenation of benzene have a series of disadvantages. Nickel catalysts are very sensitive to sulfur-containing impurities in benzene, so to protect the second reactor to which the nickel catalyst is fed, use very pure benzene for hydrogenation, or relatively in the main reactor, as described in GB 1 104 275. It is necessary to use platinum catalysts that withstand high sulfur contents. It is also possible to dope the catalyst with rhenium (GB 1 155 539) or to prepare the catalyst using ion exchange materials (GB 1 144 499). However, the preparation of such catalysts is complicated and cost intensive. Hydrogenation can also be carried out on Raney nickel (US 3 202 723), but this catalyst has the disadvantage of high combustion potential. In addition, a homogeneous nickel catalyst can also be used for hydrogenation (EP-A 0 668 257). However, since these catalysts are very sensitive to moisture, the benzene used must be dried before the hydrogenation until the residual moisture content is <1 ppm in the drying column. Another disadvantage of homogeneous catalysts is that they cannot be regenerated.

Platinum catalysts have less disadvantages than nickel catalysts, but are much more expensive to manufacture. Both platinum catalysts and nickel catalysts must use very high hydrogenation temperatures, which can result in significant formation of unwanted byproducts.

Ruthenium catalysts are not used industrially to hydrogenate benzene to cyclohexane, but this application refers to the use of ruthenium containing catalysts.

In SU 319582 a Ru suspension catalyst doped with Pd, Pt or Rh was used to prepare cyclohexane from benzene. However, using Pd, Pt or Rh makes the catalyst very expensive. In addition, the processing and recovery of the catalyst is complicated, and the suspension catalyst is expensive.

In SU 403658 Cr doped Ru catalyst was used to prepare cyclohexane. However, hydrogenation was carried out at 180 ° C. and unwanted byproducts were produced in significant amounts.

US 3 917 540 claims an Al ₂ O ₃ supported catalyst for preparing cyclohexane. They contain alkali metals and technetium or rhenium with the noble metals selected from transition group VIII of the periodic table as active metals. However, hydrogenation of benzene can be carried out with only 99.5% selectivity on such catalysts.

Finally, US 3 244 644 describes a η-Al ₂ O ₃ supported ruthenium hydrogenation catalyst which is known to be particularly suitable for the hydrogenation of benzene. However, this catalyst contains at least 5% of the active metal, and the production of η-Al ₂ O ₃ is complicated and cost-intensive.

The present invention provides a process for obtaining a corresponding alicyclic compound by hydrogenating an unsubstituted or alkyl substituted monocyclic or polycyclic aromatic compound with a hydrogen containing gas in the presence of a catalyst containing a large pore. A method for hydrogenating benzene to obtain cyclohexane.

OBJECT OF THE INVENTION The present invention relates to a process for the hydrogenation of monocyclic or polycyclic aromatic compounds, which may be unsubstituted or substituted by one or more alkyl groups, to form the corresponding alicyclic compounds, in particular by hydrogenating benzene to cyclohexane And a method for obtaining an alicyclic compound under very high selectivity and space-time yield.

The inventors have found that one or more monocyclic or polycyclic aromatic compound (s) for this purpose, which may be unsubstituted or substituted by one or more alkyl groups, may be provided with at least one metal selected from the transition group VIII of the periodic table, in particular ruthenium. It has been found that this is achieved by a method of hydrogenating these aromatic compound (s) by contact with a hydrogen containing gas in the presence of a catalyst containing with an active metal applied to a support containing.

It has been surprisingly found that even at much lower temperatures than those used in the prior art, such aromatic compounds can be hydrogenated selectively and under high space-time yields on catalysts containing such pores to obtain the corresponding alicyclic compounds. At low temperatures that can be used according to the invention, the formation of unwanted by-products such as methylcyclopentane or other n-paraffins is substantially completely inhibited, thus eliminating the need for complicated purification of the resulting alicyclic compounds.

Another advantage of using ruthenium as the active metal is that it is significantly lower in price than other hydrogenated metals such as palladium, platinum or rhodium.

In a preferred embodiment, the present invention provides a catalyst comprising, alone or at least one metal of transition group VIII of the periodic table as the active metal applied to a support having an average pore size of at least 50 nm and a BET surface area of 30 m 2 / g or less. Together with at least one metal of transition group I or VII, wherein the content of the active metal is from 0.01% to 30% by weight based on the total weight of the catalyst (catalyst 1). It is more preferable that the average pore diameter of the support in this catalyst is at least 0.1 µm and the BET surface area is at most 15 m 2 / g (catalyst 1a).

In addition, the present invention is a catalyst, wherein 10% to 50% of the pore volume is composed of large pores having a pore diameter of 50 nm to 10,000 nm, 50% to 90% of the pore volume is a medium having a pore diameter of 2 nm to 50 nm It is composed of pores, the sum of the pore volume fractions being 100% or less of the active metal applied to the support, alone or at least one metal of transition group VIII of the periodic table, or at least one metal of transition group I or VII of the periodic table Together with an amount of from 0.01 to 30% by weight, based on the total weight of the catalyst. Supports that can be used are mainly any support containing large pores, that is, a support containing only large pores, and a support containing not only large pores but also mesopores and / or micropores.

As the active metal, mainly all metals of transition group VIII of the periodic table can be used. Preferred active metals are platinum, rhodium, palladium, cobalt, nickel or ruthenium or mixtures of two or more thereof, particularly preferably ruthenium. It is preferable to use copper and / or rhenium among the transition groups I or VII of the periodic table which can likewise be used, or the transition groups I and VII which can likewise be mainly used together.

The terms "pore" and "pore" as used herein are described in Pure Appl. Chem., 45 , p. 79 (1976), that is to say defined as pores with a diameter of about 50 nm or more (pores) or pores with a diameter of 2 nm to 50 nm (medium pores). . "Micropore" is also as defined in the literature, and refers to pores having a diameter <2 nm.

The active metal content is usually from about 0.01% to about 30% by weight, preferably from about 0.01% to about 5% by weight, in particular from about 0.1% to about 5% by weight, based on the total weight of the catalyst used, The contents preferably used for the preferred catalysts 1 and 2 shown below are indicated one or more times in the description of these catalysts, respectively.

Hereinafter, preferred catalysts 1 and 2 will be described in more detail. This description is given by taking an example of the use of ruthenium as an active metal. However, the following description may also apply to other active metals that may be used as defined herein.

Catalyst 1

Catalyst 1 used according to the invention can be industrially prepared by applying one or more metals of transition group VIII of the periodic table and, if necessary, one or more metals of transition group I or VII of the periodic table to a suitable support.

Application of the metal (s) can be accomplished by immersing the support in an aqueous metal salt solution, such as an aqueous ruthenium salt solution, or by spraying a corresponding metal salt solution onto the support, or by other suitable methods. Suitable metal salts of transition groups I, VII or VIII of the periodic table are nitrates, nitrosyl nitrates, halides, carbonates, carboxylates, acetylacetonates, chloro complexes, nitrito complexes or amine complexes of the corresponding metals, nitrates and nitrosyls Nitrate is preferred.

In the case of a catalyst having a transition metal of the periodic table VIII as well as another metal applied to the support with an active metal, the metal salt or metal salt solution can be applied simultaneously or continuously.

The support coated with or impregnated with the metal salt solution is then preferably dried at 100 to 150 ° C and calcined at 200 to 600 ° C, preferably 350 to 450 ° C, if necessary. In the case of separate impregnation, after each impregnation step, the catalyst is dried and, if necessary, calcined as described above. The order of applying the active ingredients can be chosen at will.

After coating, drying, and optionally calcined, the support is then activated by treatment in a gas stream containing free hydrogen at about 30 ° C to about 600 ° C, preferably about 150 ° C to about 450 ° C. The gas stream preferably consists of 50% by volume to 100% by volume of H ₂ and 0 to 50% by volume of N ₂ .

The metal salt solution (s) has a total active metal content of about 0.01% to about 30% by weight, preferably about 0.01% to about 5% by weight, more preferably about 0.01% by weight, based on the total weight of the catalyst To the support (s) in an amount of from about 1% by weight, in particular from about 0.05% to about 1% by weight.

The total metal surface area for Catalyst 1 is preferably about 0.01 to about 10 m 2 / g (catalyst), more preferably about 0.05 to about 5 m 2 / g (catalyst), and about 0.05 m 2 / g to about 3 m 2 It is especially preferable that it is / g (catalyst). Metal surface areas are described in J. Lemaitre el al. in "Characterization of Heterogeneous Catalysts", edited by Francis Delanney, Marcel Dekker, New York 1984, pp. It is measured by the chemical adsorption method described in [310-324].

In Catalyst 1 used according to the invention, the ratio of the surface area of the active metal (s) to the surface area of the catalyst support is preferably less than about 0.05, with a lower limit of about 0.0005.

Support materials that can be used to prepare the catalysts used according to the invention have pores and have an average pore diameter of at least about 50 nm, preferably at least about 100 nm, in particular at least about 500 nm, and have a BET surface area About 30 m 2 / g or less, preferably about 15 m 2 / g or less, more preferably about 10 m 2 / g or less, in particular about 5 m 2 / g or less, particularly preferably about 3 m 2 / g or less. The average pore diameter of the support is preferably about 100 nm to about 200 μm, more preferably about 500 nm to about 50 μm. The BET surface area of the support is preferably about 0.2 m 2 / g to about 15 m 2 / g, more preferably about 0.5 m 2 / g to about 10 m 2 / g, and about 0.5 m 2 / g to about 5 m 2 / g Particular preference is given, even more preferably from about 0.5 m 2 / g to about 3 m 2 / g.

The surface area of the support is measured in particular by the BET method using N ₂ adsorption according to DIN 66131. The measurement of the mean pore diameter and pore size distribution is carried out using a Hg porous system, in particular according to DIN 66133.

It may be advantageous for the pore size distribution of the support to be approximately atypical, with the pore diameter distribution having a peak at about 500 nm and about 20 μm in a heterogeneous distribution representing a specific embodiment of the invention.

More preferred is a support having a surface area of 1.75 m 2 and a pore diameter having a heterogeneous distribution. The pore volume of this preferred support is preferably about 0.53 ml / g.

Usable support materials with pores are, for example, activated carbon with pores, silicon carbide, aluminum oxide, silicon dioxide, titanium dioxide, zirconium dioxide, magnesium oxide, zinc oxide or mixtures of two or more thereof, aluminum oxide And zirconium dioxide are particularly preferred.

Further details regarding catalyst 1 and its preparation are described in DE-A 196 24 484.6, the content of which is hereby incorporated by reference in its entirety.

The support material which can be used to prepare the catalyst 1a to be used according to the present invention, which shows a preferred embodiment of the catalyst 1, has a large pore, an average pore diameter of at least 0.1 mu m, preferably at least 0.5 mu m, and the surface area is 15 m 2 / g or less, preferably 10 m 2 / g or less, particularly preferably 5 m 2 / g or less, especially 3 m 2 / g or less. The average pore diameter of the support used in the present invention is preferably 0.1 μm to 200 μm, especially 0.5 μm to 50 μm. The surface area of the support is preferably 0.2 m 2 to 15 m 2 per g of support, particularly preferably 0.5 m 2 to 10 m 2 per g of support, even more preferably 0.5 m 2 to 5 m 2 per g of support. Most preferred is 0.5 m 2 to 3 m 2 per gram. This catalyst also has a bimodal pore diameter distribution described above with similar distribution and corresponding preferred pore volume. Further details regarding catalyst 1a are described in DE-A 196 04 791.9, the contents of which are hereby incorporated by reference in detail.

Catalyst 2

Catalyst 2 used according to the present invention, as defined herein, comprises one or more metals of transition group VIII of the periodic table as the active component (s) on the support. Preference is given to using ruthenium, palladium and / or rhodium as active ingredient (s).

Catalyst 2 used according to the invention is industrially applied by applying one or more active metals of transition group VIII of the periodic table, preferably ruthenium, and optionally one or more metals of transition group I or VII of the periodic table to a suitable support. It can manufacture. Application of the metal (s) can be accomplished by immersing the support in an aqueous metal salt solution (eg, ruthenium salt solution), spraying the corresponding metal salt solution onto the support, or by other suitable methods. Metal salts suitable for preparing metal salt solutions are nitrates, nitrosyl nitrates, halides, carbonates, carboxylates, acetylacetonates, chloro complexes, nitrito complexes or amine complexes of the corresponding metals, with nitrates and nitrosyl nitrates being preferred. .

In the case of catalysts containing a large number of active metals applied to the support, the metal salts or metal salt solutions can be applied simultaneously or sequentially.

The support coated with or immersed in the metal salt solution is then dried, preferably at a temperature of 100 to 150 ° C. If necessary, these supports can be calcined at 200 to 600 ° C, preferably 350 to 450 ° C. The coated support is then activated by treatment at 30-600 ° C., preferably 100-450 ° C., in particular 100-300 ° C., in a gas stream containing free hydrogen. The gas stream preferably consists of 50% by volume to 100% by volume of H ₂ and 0 to 50% by volume of N ₂ .

When apply | coating two or more active metals to a support body and apply | coating continuously, a support body can be dried at 100-150 degreeC after each application, and can be calcined at 200-600 degreeC as needed. The order of applying the metal salt solution can be selected at will.

The metal salt solution has an active metal content of 0.01% to 30% by weight, preferably 0.01% to 10% by weight, more preferably 0.01% to 5% by weight, in particular 0.3% by weight, based on the total weight of the catalyst The amount is applied to the support (s) in an amount of 1 to 1% by weight.

The total metal surface area on the catalyst is preferably from 0.01 m 2 to 10 m 2 per g of catalyst, particularly preferably from 0.05 m 2 to 5 m 2 per g of catalyst, more preferably from 0.05 m 2 to 3 m 2 per g of catalyst. Metal surface areas are described in J. Lemaitre et al., "Characterization of Heterogeneous Catalysts", edited by Francis Delanny, Marcel Dekker, New York (1984), pp. 310-324].

In Catalyst 2 used according to the invention, the ratio of the surface area of the active metal (s) to the surface area of the catalyst support is less than about 0.3, preferably less than about 0.1, in particular about 0.05 or less and the lower limit is about 0.0005.

The support material that can be used to prepare Catalyst 2 used according to the invention has large pores and mesopores.

Thus, the support which can be used according to the invention comprises from about 5% to about 50%, preferably from about 10% to about 45%, more preferably from about 10% to about 30%, in particular about 15% of the pore volume. To about 25% consists of large pores having a pore diameter of about 50 nm to about 10,000 nm, about 50% to about 95%, preferably about 55% to about 90%, more preferably about 70% of the pore volume. To about 90%, in particular about 75% to about 85% have a pore volume consisting of mesopores having a pore diameter of about 2 nm to about 50 nm, wherein the sum of the pore volume ratios is 100%.

The total pore volume of the support used according to the invention is about 0.05 cm 3 / g to 1.5 cm 3 / g, preferably 0.1 cm 3 / g to 1.2 cm 3 / g, in particular about 0.3 cm 3 / g to 1.0 cm 3 / g. The average pore diameter of the support used according to the invention is about 5 nm to 20 nm, preferably about 8 nm to about 15 nm, in particular about 9 nm to about 12 nm.

The surface area of the support is preferably from about 50 m 2 to about 500 m 2 per g of support, more preferably from about 200 m 2 to about 350 m 2 per g of support, in particular from about 250 m 2 to about 300 m 2 per g of support. It is preferable.

The surface area of the support is measured in particular by the BET method using N ₂ adsorption according to DIN 66131. The measurement of the average pore diameter and size distribution is carried out in particular with a Hg porosity system according to DIN 66133.

All support materials known in the manufacture of catalysts having a pore size distribution as defined above can be used predominantly. Preference is given to using activated carbon, silicon carbide, aluminum oxide, silicon dioxide, titanium dioxide, zirconium dioxide, magnesium oxide, zinc oxide or mixtures thereof, more preferably aluminum oxide and zirconium dioxide.

Further details regarding Catalyst 2 are described in DE-A 196 24 485.4, the content of which is hereby incorporated by reference in detail.

How to do it

In the process of the invention, all monocyclic or polycyclic aromatic compounds which are unsubstituted or having one or more alkyl groups can be used individually or as a mixture of two or more thereof, preferably individually. The length of the alkyl group is not particularly limited, but the alkyl group is usually C ₁ -C ₃₀ , preferably C ₁ -C ₁₈ , especially C ₁ -C ₄ alkyl groups. Specific examples of starting materials for the process of the invention include in particular the following aromatic materials.

Benzene, toluene, xylene, cumene, diphenylmethane, tribenzene, tetrabenzene, pentabenzene and hexabenzene, triphenylmethane, alkyl substituted naphthalene, naphthalene, alkyl substituted anthracene, anthracene, alkyl substituted tetralin and te Traline.

In the process of the invention, it is preferable to hydrogenate benzene to form cyclohexane.

In the process of the invention, the hydrogenation is usually carried out at about 50-250 ° C, preferably at about 70-200 ° C, more preferably at about 80-180 ° C, in particular at about 80-150 ° C. Here, the lowest temperature can be used when ruthenium is used as the active metal. The pressure used is usually at least 1 bar, preferably from about 1 bar to about 200 bar, more preferably from about 10 bar to about 50 bar.

The process of the invention can be carried out continuously or batchwise, preferably carried out continuously.

In a continuous process, the amount of aromatic compound to be hydrogenated is from about 0.05 kg to about 3 kg per liter of catalyst per hour, more preferably from about 0.2 kg to about 2 kg per liter of catalyst per hour.

As the hydrogenation gas, any gas containing free hydrogen and not containing a catalytic toxic substance such as CO in a harmful amount can be used. For example, reformed waste gas can be used. Pure hydrogen is preferably used as the hydrogenation gas.

The hydrogenation of the invention can be carried out in the presence or absence of a solvent or diluent, ie it is not necessary to carry out the hydrogenation in solution.

Any suitable solvent or diluent may be used as the solvent or diluent. If the solvent or diluent used is capable of forming a homogeneous solution with the aromatic compound to be hydrogenated, the choice is not important.

The amount of solvent or diluent used is not limited in any particular manner, and may be freely selected according to requirements, and is preferably in an amount capable of forming a 10 to 70 wt% solution of the aromatic compound to be hydrogenated.

When using a solvent, the product formed in the hydrogenation, i.e. each alicyclic compound (s), is used as solvent in the process of the invention together with other solvents or diluents as necessary. In each case, part of the product formed in the process can be mixed with the aromatic compound to be hydrogenated. The amount of the product mixed as the solvent or the diluent is preferably 1 to 30 times, particularly preferably 5 to 20 times, more preferably 5 to 10 times, based on the weight of the aromatic compound to be hydrogenated. In particular, the present invention provides a hydrogenation of the type which hydrogenates benzene to cyclohexane at 80-150 ° C. in the presence of catalyst 2 as defined herein.

In a specific embodiment of the process of the invention, benzene is reacted at 80-150 ° C. and the active metal used is ruthenium alone.

Hereinafter, the present invention will be described through examples.

Preparation Example of Catalyst

An aluminum oxide support having 3 to 5 mm spherical mesopores / pores with a total pore volume of 0.44 cm 3 / g was immersed in an aqueous solution of ruthenium (III) nitrate, which was 0.09 cm 3 / g (total pore volume). 20%) consists of pores from 50 nm to 10,000 nm in diameter, 0.35 cm 3 / g of total pore volume (80% of total pore volume) consists of pores from 2 nm to 50 nm in diameter, average pore The diameter is 11 nm and the surface area is 268 m 2 / g. The volume of solution absorbed by the support during the soaking process corresponds approximately to the pore volume of the support used. The support impregnated with the ruthenium (III) nitrate solution was then dried at 120 ° C. and activated (reduced) at 200 ° C. under a hydrogen stream. The catalyst prepared in this way contained 0.5 weight percent ruthenium based on the weight of the catalyst. The surface area of ruthenium was 0.72 m 2 / g, and the ratio of ruthenium surface area to the support surface area was 0.0027 (catalyst A).

Liquid Hydrogenation

Example 1

10 g of Catalyst A was placed in a basket insert in a 300 ml pressurized reactor. The reactor was then charged with 100 g of benzene. Hydrogenation was carried out using pure hydrogen at 80 ° C. under a pressure of 50 bar. The hydrogenation continued until no more hydrogen was adsorbed and then the reactor was evacuated. The yield of cyclohexane was 99.99%. Methylcyclopentane was not detected.

Example 2

10 g of Catalyst A was placed in a basket insert in a 300 ml pressurized reactor. The reactor was then charged with 100 g of benzene. Hydrogenation was carried out using pure hydrogen at 80 ° C. under a pressure of 20 bar. The hydrogenation continued until no more hydrogen was adsorbed and then the reactor was evacuated. The yield of cyclohexane was 99.99%. Methylcyclopentane was not detected.

Example 3

10 g of Catalyst A was placed in a basket insert in a 300 ml pressurized reactor. The reactor was then charged with 100 g of benzene. Hydrogenation was carried out using pure hydrogen at 120 ° C. under a pressure of 20 bar. The hydrogenation continued until no more hydrogen was adsorbed and then the reactor was evacuated. The yield of cyclohexane was 99.99%. Methylcyclopentane was not detected.

Example 4

10 g of Catalyst A was placed in a basket insert in a 300 ml pressurized reactor. The reactor was then charged with 100 g of benzene. Hydrogenation was carried out using pure hydrogen at 150 ° C. under a pressure of 20 bar. The hydrogenation continued until no more hydrogen was adsorbed and then the reactor was evacuated. The yield of cyclohexane was 99.99%. 57 ppm of methylcyclopentane was detected in cyclohexane.

Example 5

2 kg of catalyst A was charged to an electrically heated through reactor. The hydrogenation of benzene was then initiated at 2 × 10 ⁶ Pa and 75 ° C. without prior activation. The hydrogenation was carried out continuously in an upstream manner, with some of the hydrogenation product recycled through a circulation pump and mixed with the starting material upstream of the reactor. Based on the amount of benzene, 10 times the amount of hydrogenation product amount was added as solvent. At the top of the separator, 200 L of H ₂ / h was discharged. The amount of benzene continuously fed to the reactor corresponded to a space velocity of 0.76 kg / lx h on the catalyst. The hydrogenation product was pumped upstream through a second hydrogenation reactor (second reactor), also filled with 2 kg of Catalyst A at 85 ° C. and 2 × 10 ⁶ Pa. In this reactor, the hydrogenation product was not recycled. The hydrogenation product had a residual benzene content of 80 ppm (measured by gas chromatography). Methylcyclopentane was not detected.

Example 6

2 kg of catalyst A was charged to an electrically heated through reactor. The hydrogenation of benzene was then initiated at 5 × 10 ⁶ Pa and 150 ° C. without prior activation. The hydrogenation was carried out continuously in an upstream manner, with some of the hydrogenation product being recycled through a circulation pump and mixed with the starting material upstream of the reactor. Based on the amount of benzene, 20 times the amount of hydrogenation product amount was added as solvent. At the top of the separator, 200 L of H ₂ / h was discharged. The amount of benzene continuously fed to the reactor corresponded to a space velocity of 1.5 kg / l × h on the catalyst. The hydrogenation product was pumped upstream through a second hydrogenation reactor (second reactor), also filled with 2 kg of catalyst A at 85 ° C. and 5 × 10 ⁶ Pa. In this reactor, the hydrogenation product was not recycled. The hydrogenation product had a residual benzene content of 50 ppm (measured by gas chromatography). Methylcyclohentan was not detected.

Gas phase hydrogenation

Example 7

An oil heated through reactor (glass) was charged with 110 ml of Catalyst A (70 g). Subsequently, hydrogenation of benzene was initiated under atmospheric pressure, without prior activation. Here, benzene was evaporated using a preliminary evaporator (80 ° C.) and continuously passed through a catalyst bed under 100 ° C. with hydrogen (molar ratio = 1: 7.4) in a single pass form at a space velocity of 0.3 kg / L * hour. . The product was condensed in a cold trap. In this way, benzene can be fully hydrogenated to cyclohexane. 31 ppm of methylcyclopentane was detected in cyclohexane.

Example 8

An oil heated through reactor (glass) was charged with 40 ml of Catalyst A (25 g). Subsequently, hydrogenation of benzene was initiated under atmospheric pressure, without prior activation. Here, benzene was evaporated by a preliminary evaporator (80 ° C.) and continuously passed through a catalyst bed at 120 ° C. with hydrogen (molar ratio = 1: 7.4) in a single pass form at a space velocity of 1.0 kg / L * hour. The conversion of benzene was 93%.

The condensed hydrogenation product was passed upstream through a downstream tube reactor filled with 50 g of catalyst at 85 ° C. and 5 × 10 ⁶ Pa (liquid phase). The hydrogenation product had a residual benzene content of 30 ppm (measured by gas chromatography). 41 ppm of methylcyclopentane was detected.

Claims (10)

One or more monocyclic or polycyclic aromatic compound (s), unsubstituted or substituted by one or more alkyl groups, contains one or more metals of transition group VIII of the periodic table as active metals applied to the support containing the pores Contacting a hydrogen containing gas in the presence of a catalyst to hydrogenate said aromatic compound (s). 2. The catalyst of claim 1, wherein the catalyst is an active metal applied to a support having an average pore diameter of 50 nm or more and a BET surface area of 30 m 2 / g or less, alone or in combination with one or more metals of transition group VIII of the periodic table. Comprising at least one metal of I or VII, wherein the amount of active metal is from 0.01% to 30% by weight based on the total weight of the catalyst. The catalyst of claim 1 wherein the catalyst comprises 10% to 50% of the pore volume consisting of large pores having a pore diameter of 50 nm to 10,000 nm, and 50% to 90% of the pore volume having a pore diameter of 2 nm to 50 nm. From 0.01% by weight, based on the total weight of the catalyst, as an active metal applied to a support consisting of mesopores, alone or in combination with one or more metals of transition group VIII of the periodic table, or with one or more metals of transition group I or VII of the periodic table 30% by weight, wherein the sum of the pore volume fractions is 100%. 2. The catalyst of claim 1, wherein the catalyst is an active metal applied to a support having an average pore diameter of at least 0.1 µm and a BET surface area of 15 m 2 / g or less, alone or at least one metal of transition group VIII of the periodic table. Together with at least one metal of Group I or VII in an amount of from 0.01% to 30% by weight, based on the total weight of the catalyst. 5. The monocyclic or polycyclic aromatic compound according to claim 1, wherein the monocyclic or polycyclic aromatic compound is selected from the group consisting of benzene, toluene, xylene, cumene, diphenylmethane, tribenzene, tetrabenzene, pentabenzene and hexabenzene, triphenyl. Methane, alkyl substituted naphthalene, naphthalene, alkyl substituted anthracene, anthracene, alkyl substituted tetralin and tetralin. The method of claim 5 wherein benzene is reacted to form cyclohexane. The process according to any one of claims 1 to 6, wherein the hydrogenation is carried out at 50 to 250 ° C. The process of claim 3 wherein benzene is reacted at 80-150 ° C. and the active metal used is ruthenium alone. 9. The support of claim 1, wherein the support comprises activated carbon, silicon carbide, aluminum oxide, silicon dioxide, titanium dioxide, zirconium dioxide, magnesium oxide, zinc oxide, or a mixture of two or more thereof. Which method. The process according to claim 1, wherein the hydrogenation is carried out continuously.