EP2512658A2

EP2512658A2 - Catalyst and method for hydrogenating aromates

Info

Publication number: EP2512658A2
Application number: EP10792900A
Authority: EP
Inventors: Lucia KÖNIGSMANN; Daniela Mirk; Thomas Heidemann; Michael Hesse; Martin Bock; Mario Emmeluth; Jutta Bickelhaupt
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 2009-12-15
Filing date: 2010-12-14
Publication date: 2012-10-24
Also published as: CN102753266B; US20120296111A1; KR101833077B1; KR20120092197A; US9084983B2; JP5745538B2; WO2011082991A2; CN102753266A; JP2013513477A; WO2011082991A3

Abstract

The present invention relates to a shell catalyst, comprising an active metal selected from the group of ruthenium, rhodium, palladium, platinum, and mixtures thereof, applied to a carrier material comprising silicon dioxide, wherein the pore volume of the carrier material is 0.6 to 1.0 ml/g, determined by Hg porosimetry, the BET surface area is 280 to 500 m²/g, and at least 90% of the pores present comprise a diameter from 6 to 12 nm, to a method for producing said shell catalyst, to a method for hydrogenating an organic compound comprising at least one hydrogenatable group using the shell catalyst, and to the use of the shell catalyst for hydrogenating an organic compound.

Description

The present invention relates to a coated catalyst comprising an active metal selected from the group consisting of ruthenium, rhodium, palladium, platinum and mixtures thereof, applied to a support material comprising silicon dioxide, wherein the pore volume of the support material is 0.6 to 1, 0 ml / g, determined by Hg porosimetry, the BET surface area is 280 to 500 m ² / g, and at least 90% of the pores present have a diameter of 6 to 12 nm, a method for producing this A coated catalyst, a process for hydrogenating an organic compound containing at least one hydrogenatable group using the coated catalyst, and the use of the coated catalyst for the hydrogenation of an organic compound.

Various hydrogenation processes are known from the literature. In particular, the hydrogenation of substituted and unsubstituted aromatic compounds, benzene polycarboxylic acids, phenol or aniline derivatives are technically interesting. Furthermore, the hydrogenation products of compounds having C-C, C-O, N-O and C-N multiple bonds and polymers are also of interest. The processes described in the prior art for the hydrogenation of organic compounds are in the presence of appropriate catalysts, in particular supported catalysts, d. H. an active metal is applied to a substrate carried out. WO 2006/136541 A2 discloses a catalyst and a process for hydrogenating organic compounds containing hydrogenatable groups. In the process according to this document, a coated catalyst is used which contains as active metal ruthenium alone or together with at least one further metal of transition groups IB, VIIB or VIII of the Periodic Table of the Elements, applied to a support comprising silicon dioxide as support material. Further disclosed is a process for producing this coated catalyst, a process for hydrogenating an organic compound containing hydrogenatable groups, and the use of the corresponding catalyst in the hydrogenation of organic compounds containing a hydrogenatable group. The coated catalyst used in this process is characterized in that the active metal to a particularly high proportion in a penetration depth of 300 to 1000 μηη, relative to the substrate surface, is present.

DE 197 34 974 A1 discloses a process for the preparation of porous supported metal nanoparticle-containing catalysts, in particular for the gas phase oxidation of ethylene and acetic acid to vinyl acetate. The catalyst according to this document can a shell catalyst, wherein the surface area of the support material, measured by the BET method, is generally 10 to 500 m ² / g, the pore volume is generally 0.3 to 1.2 ml / g. Suitable active metals include rhodium, ruthenium, palladium or platinum. The support material according to this document is nanoporous, wherein nanopores with a pore size in the range of 1 to 500 nm are present.

WO 99/32427 discloses a process for the hydrogenation of benzene polycarboxylic acids or derivatives thereof using a macroporous catalyst. This catalyst contains as the active metal ruthenium alone or together with at least one metal of the I, VII. Or VIII. Subgroup of the Periodic Table, applied to a support, wherein the support has macropores. In particular, the pores of the carrier material have an average diameter of at least 50 nm and a BET surface area of at most 30 m ² / g.

EP 0 814 098 B1 discloses a process for reacting an organic compound in the presence of a supported ruthenium catalyst. The catalyst according to this document is characterized in that it comprises as active metal ruthenium alone or together with at least one metal of the I, VII or VIII subgroup of the periodic table in an amount of 0.01 to 30 wt .-% based on the total weight of the catalyst supported on a support, wherein 10 to 50% of the pore volume of the support is formed by macropores having a diameter in the range of 50 nm to 10,000 nm. EP 1 266 882 B1 discloses a process for the preparation of cyclohexanedicarboxylic acid esters by hydrogenating the corresponding benzenedicarboxylic acid esters in the presence of a suitable catalyst. The catalyst according to this document contains as active metal nickel in an amount of 5 to about 70 wt .-%.

WO 2004/009526 A1 also discloses a microporous catalyst and a process for the hydrogenation of aromatic compounds using this catalyst. The cited document mentions catalysts which have an average pore diameter of 5 to 20 nm and a BET surface area> 50 m ² / g. The amount of active metal ruthenium is 0.1 to 30 wt .-%, and the BET surface area is between 1 and 350 m ² / g. The pore volume of the carrier material used, for example silicon dioxide, is at low values of 0.28 to 0.43 ml / g. WO 03/103830 A1 discloses a catalyst and a process for the hydrogenation of aromatic compounds using this catalyst. The catalyst according to this document contains as active material at least one metal of VIII. Subgroup and a support material having an average pore diameter of 25 to 50 nm and a specific surface area of> 30 m ² / g.

DE 196 24 835 A1 discloses a process for the hydrogenation of polymers with ruthenium or palladium catalysts. The support material of the catalyst according to this document has a specific pore size distribution, wherein 10 to 50% of the pore volume of the support of macropores having a pore diameter in the range of 50 nm to 10,000 nm and 50 to 90% of the pore volume of the support of mesopores having a pore diameter in Range of 2 to 50 nm are formed. Furthermore, the catalyst according to this document is a full catalyst, i. h., That the active metal is distributed over the entire cross-section of the catalyst particles.

The catalysts which are already known from the prior art, as well as the processes for the hydrogenation of aromatic compound using these catalysts are still in need of improvement. On the one hand, the conversion should be increased to the desired target compound, for example a carbocyclic aliphatic compound derived from the corresponding aromatic compound. Furthermore, the selectivity of the catalysts can be further increased with respect to the desired product.

It is therefore an object of the present invention over the prior art to provide a catalyst which gives the highest possible conversion in the hydrogenation of organic compounds with at the same time a particularly high selectivity with respect to the desired target product. Furthermore, the catalysts according to the invention are said to have a particularly high stability, ie. H. a very long life.

These objects are achieved by a coated catalyst containing an active metal selected from the group consisting of ruthenium, rhodium, palladium, platinum and mixtures thereof, applied to a support material containing silicon dioxide, characterized in that the pore volume of the support material 0.6 to 1, 0 ml / g, determined by Hg porosimetry, the BET surface area is 280 to 500 m ² / g, and at least 90% of the pores present have a diameter of 6 to 12 nm. Further inventive solutions of the stated objects are a process for the preparation of this catalyst, and a process for the hydrogenation of organic compounds which have at least one hydrogenatable group. The solution of the stated object is based on a coated catalyst containing an active metal selected from the group consisting of ruthenium, rhodium, palladium, platinum and mixtures thereof, which has a very specific combination of certain characteristics, the catalyst a particularly high activity and selectivity, for example the hydrogenation of organic compounds.

The coated catalyst according to the invention contains an active metal selected from the group consisting of ruthenium, rhodium, palladium, platinum and mixtures thereof, preferably ruthenium, very particularly preferably ruthenium as the only active metal.

In the coated catalyst according to the invention, the amount of the active metal is generally <1 wt .-%, preferably 0.1 to 0.5 wt .-%, particularly preferably 0.25 to 0.35 wt .-%, based on the total weight of catalyst. The present invention therefore preferably relates to the coated catalyst according to the invention, wherein the amount of the active metal is 0.1 to 0.5 wt .-%, particularly preferably 0.25 to 0.35 wt .-%, based on the total weight of the catalyst.

Shell catalysts are known per se to those skilled in the art. In the context of the present invention, the term "shell catalyst" means that the existing at least one active metal, preferably ruthenium, is for the most part present in an outer shell of the support material.

In the shell catalysts according to the invention are preferably 40 to 70 wt .-%, more preferably 50 to 60 wt .-% of the active metal, based on the total amount of the active metal, in the shell of the catalyst to a penetration depth of 200 μηη before. In a particularly preferred embodiment, 60 to 90% by weight, very particularly preferably 70 to 80 wt .-% of the active metal, based on the total amount of the active metal, in the shell of the catalyst to a penetration depth of 500 μηη before. The above data are obtained by SEM (electron probe microanalysis) - EDXS (energy dispersive X-ray spectroscopy) and represent averaged values. Further information regarding the above measurement methods and techniques is available, for example, "Spectroscopy in Catalysis "by JW Niemantsverdriet, VCH, 1995 or" Handbook of Microscopy "by S. Amelinckx et al. To determine the penetration depth of the In the case of solid metal particles, several catalyst particles (for example 3, 4 or 6) are ground. The profiles of the active metal / Si concentration ratios are then recorded by means of line scans. On each measuring line several, for example 15 to 20, measuring points are measured at equal intervals, the measuring spot size is approximately 10 μηη ^* 10 μηη. After integration of the amount of active metal across the depth, the frequency of the active metal in a zone can be determined.

The coated catalyst according to the invention is preferably characterized in that the predominant amount of the active metal in the shell is present up to a penetration depth of preferably 200 μm, ie near the surface of the coated catalyst. In contrast, there is preferably no or only a very small amount of the active metal in the interior (core) of the catalyst. Surprisingly, it has been found that the catalyst according to the invention - despite the small amount of active metal - due to the special combination of certain features a very high activity in the hydrogenation of organic compounds containing at least one hydrogenatable groups, especially in the hydrogenation of carbocyclic aromatic groups , with very good selectivities. In particular, the activity of the catalyst according to the invention does not decrease over a long hydrogenation period. Very particular preference is given to a coated catalyst according to the invention in which no active metal can be detected inside the catalyst, i. Active metal is present only in the outermost shell, for example in a zone up to a penetration depth of up to 500 μm. Most preferably, the amount of the active metal, based on the concentration ratio of active metal to Si, on the surface of the shell catalyst, 2 to 25%, preferably 4 to 10%, particularly preferably 4 to 6%, determined by means of SEM EPMA - EDXS. The surface analysis is carried out by means of area analyzes of areas of 800 μπΊ x 2000 μηη and with an information depth of about 2 μηη. The elemental composition is determined in% by weight (normalized to 100% by weight). The mean concentration ratio (active metal / Si) is averaged over 10 measuring ranges.

For the purposes of the present application, the surface of the shell catalyst is understood to be the outer shell of the catalyst up to a penetration depth of approximately 2 μm. This penetration depth corresponds to the information depth in the above-mentioned surface analysis.

Very particularly preferred is a coated catalyst in which the amount of the active metal, based on the weight ratio of active metal to Si (wt / wt in%), at the surface of the shell catalyst is 4 to 6%, in a penetration depth of 50 μπΊ 1, 5 to 3% and in the range of 50 to 150 μηη penetration 0.5 to 2%, determined by means of SEM EPMA (EDXS), is. The stated values represent averaged values.

Furthermore, the size of the active metal particles preferably decreases with increasing penetration, as determined by (FEG) TEM analysis.

The active metal is preferably partially or completely crystalline in the coated catalyst according to the invention. In preferred cases, very finely crystalline active metal can be detected in the shell of the coated catalyst according to the invention by means of SAD (Selected Area Diffraction).

The coated catalyst according to the invention may additionally contain alkaline earth metal ions (M ²⁺ ), ie M = Be, Mg, Ca, Sr and / or Ba, in particular Mg and / or Ca, very particularly Mg. The content of alkaline earth metal ion (s) (M ²⁺ ) in the catalyst is preferably from 0.01 to 1% by weight, in particular from 0.05 to 0.5% by weight, very particularly preferably from 0.1 to 0.25% by weight .-%, each based on the weight of the silica support material.

An essential constituent of the catalysts according to the invention is the support material containing silicon dioxide, preferably amorphous silicon dioxide. The term "amorphous" in this context means that the proportion of crystalline silicon dioxide phases makes up less than 10% by weight of the carrier material. However, the support materials used for the preparation of the catalysts may have superstructures, which are formed by regular arrangement of pores in the carrier material.

Suitable support materials are in principle amorphous silicon dioxide types which consist of at least 90% by weight of silicon dioxide, the remaining 10% by weight, preferably not more than 5% by weight, of the support material also being another oxidic material can, for. As MgO, CaO, Ti0 ₂ , Zr0 ₂ and / or Al ₂ 0 ₃ .

In a preferred embodiment of the invention, the support material is halogen-free, in particular chlorine-free, ie the content of halogen in the support material is generally less than 500 ppm by weight, z. In the range of 0 to 400 ppm by weight. Thus, preference is given to a coated catalyst which contains less than 0.05% by weight of halide (determined by ion chromatography), based on the total weight of the catalyst. The halide content of the support material is particularly preferably below the analytical detection limit. Preference is given to support materials containing silicon dioxide which have a specific surface area in the range from 280 to 500 m ² / g, particularly preferably 280 to 400 m ² / g, very particularly preferably 300 to 350 m ² / g (BET surface area to DIN 66131). exhibit. They may have been both natural and artificial. Examples of suitable amorphous support materials based on silica are silica gels, kieselguhr, fumed silicas and precipitated silicas. In a preferred embodiment of the invention, the catalysts comprise silica gels as support materials.

According to the invention, the pore volume of the carrier material is 0.6 to 1.0 ml / g, preferably 0.65 to 0.9 ml / g, for example 0.7 to 0.8 ml / g, determined by Hg porosimetry (DIN 66133). , In the shell catalyst according to the invention, at least 90% of the pores present have a pore diameter of 6 to 12 nm, preferably 7 to 11 nm, particularly preferably 8 to 10 nm. The pore diameter can be determined by methods known to those skilled in the art, for example by Hg porosimetry or N ₂ physisorption. In a preferred embodiment, at least 95%, more preferably at least 98%, of the pores present have a pore diameter of 6 to 12 nm, preferably 7 to 11 nm, particularly preferably 8 to 10 nm.

In the shell catalyst according to the invention, in a preferred embodiment, there are no pores which are smaller than 5 nm. Furthermore, in the coated catalyst according to the invention there are no pores which are greater than 25 nm, in particular greater than 15 nm. In this context, "no pores" means that no pores having these diameters are found by customary measuring methods, for example Hg-porosimetry or N ₂ physisorption The maceration of the coated catalyst according to the invention does not involve macropores, but exclusively mesopores within the scope of the measuring accuracy of the analytics used ,

In the preferred use of the coated catalyst according to the invention in fixed catalyst beds, one usually uses shaped bodies of the support material, which are eg. B. by extrusion, extrusion or tabletting are available and the z. As the shape of balls, tablets, cylinders, strands, rings or hollow cylinders, stars and the like, particularly preferably balls may have. The dimensions of these moldings usually range from 0.5 mm to 25 mm. Preference is given to using catalyst spheres with spheres diameters of 1.0 to 6.0 mm, more preferably 2.5 to 5.5 mm. In the coated catalyst according to the invention, dispersity of the active metal is preferably 30 to 60%, more preferably 30 to 50%. Methods for measuring the dispersity of the active metal are known per se to those skilled in the art, for example by pulse demisorption, where the determination of the noble metal dispersion (specific metal surface, crystallite size) is carried out with a CO pulse method (DIN 66136 (1 -3)).

The present invention therefore preferably relates to a coated catalyst according to the invention, wherein the dispersity of the active metal is 30 to 60%, particularly preferably 30 to 50%.

In the coated catalyst according to the invention, the surface of the active metal is preferably 0.2 to 0.8 m ² / g, particularly preferably 0.3 to 0.7 m ² / g. Methods for measuring the surface of the active metal are known per se to those skilled in the art.

The present invention therefore preferably relates to a shell catalyst according to the invention, wherein the surface of the active metal is 0.2 to 0.8 m ² / g, particularly preferably 0.3 to 0.7 m ² / g. The coated catalyst according to the invention preferably has a packing density of 400 to 600 g / l, more preferably 450 to 550 g / l.

The present invention therefore preferably relates to a coated catalyst according to the invention which has a packing density of 400 to 600 g / l, more preferably 450 to 550 g / l.

If the coated catalyst according to the invention is used in the hydrogenation of organic compounds, the very specific combination of features of the silica-containing carrier material with a specific pore volume, a BET specific surface area and a very specific pore diameter gives it a particularly high activity and selectivity with respect to the desired products.

The present invention therefore preferably relates to a coated catalyst according to the invention comprising ruthenium as active metal applied to a support material containing silicon dioxide, the pore volume of the support material being 0.6 to 1.0 ml / g, preferably 0.65 to 0.9 ml / g, for example 0.7 to 0.8 ml / g, determined by Hg porosimetry (DIN 66133) and N ₂ adsorption (DIN 66131), the BET surface area 280 to 500 m ² / g, preferably 280 to 400 m ² / g, particularly preferably 300 to 350 m ² / g, (BET surface area according to DIN 66131), and at least 90%, preferably at least 95%, particularly preferably at least 98%, of the pores present Diameter of 6 to 12 nm, preferably 7 to 1 1 nm, more preferably 8 bi 10 nm.

The preparation of the coated catalysts according to the invention is preferably carried out by first soaking the carrier material with a solution containing a precursor compound of the active metal or several times, drying the resulting solid and then reducing it. The individual process steps are described in more detail below. A further subject of the present application is thus a process for the preparation of a coated catalyst according to one of claims 1 to 5, comprising the steps: one or more impregnation of the support material containing silica with a solution containing at least one precursor compound of the active metal, followed by drying,

subsequent reduction. Step (A)

In step (A), a single or multiple impregnation of the carrier material containing silicon dioxide with a solution containing at least one precursor compound of the active metal. In general, all precursor compounds of the active metal are suitable, which can be converted in the process conditions of the invention into metallic active metal, for example, nitrates, acetonates and acetates, acetates being preferred. For the inventively preferred case that the active metal is ruthenium, for example, ruthenium (III) acetate is preferred. Further preferred precursor compounds are palladium (II) acetate, platinum (II) acetate and / or rhodium (II) acetate.

Since the amount of active metal in the coated catalyst according to the invention is very low, in a preferred embodiment, a simple impregnation takes place. It has surprisingly been found that when ruthenium (III) acetate is used as the precursor compound, shell catalysts can be obtained which are characterized, inter alia, by the substantial part of the active metal, preferably ruthenium alone, in the shell catalyst up to a penetration depth of 200 μπΊ is located. The interior of the shell catalyst has little or no active metal. Suitable solvents for providing the solution containing at least one precursor compound are water or mixtures of water or solvent with up to 50 vol .-% of one or more water or solvent-miscible organic solvents, eg. B. mixtures with CrC ₄ alkanols such as methanol, ethanol, n-propanol or isopropanol. Aqueous acetic acid or glacial acetic acid may also be used. All mixtures should be chosen so that there is a solution or phase. Preferred solvents are acetic acid, water or mixtures thereof. Particular preference is given to using a mixture of water and acetic acid as solvent, since ruthenium (III) acetate is usually present dissolved in acetic acid or glacial acetic acid. The catalyst according to the invention can also be prepared without the use of water.

In the event that more than one active metal is present on the support material, several precursor compounds can be applied simultaneously. It is also possible that different precursor compounds are applied in succession by repeated impregnation. After each impregnation step is usually dried.

Particular preference is given to impregnation with a solution of ruthenium (III) acetate alone in a soaking step.

The impregnation of the carrier material can take place in different ways and depends in a known manner on the shape of the carrier material. For example, one can spray or rinse the support material with the solution of the precursor compound or suspend the support material in the solution of the precursor compound. For example, it is possible to suspend the support material in an aqueous solution of the active metal precursor compound and to filter off the aqueous supernatant after a certain time. On the recorded amount of liquid and the active metal concentration of the solution then the active metal content of the catalyst can be controlled in a simple manner. The impregnation of the carrier material can also be carried out, for example, by treating the carrier with a defined amount of the solution of the active metal precursor compound which corresponds to the maximum amount of liquid that can absorb the carrier material. For this purpose, for example, spray the carrier material with the required amount of liquid. Suitable apparatuses for this purpose are the apparatuses commonly used for mixing liquids with solids (see Vauck / Müller, Basic Operations of Chemical Process Engineering, 10th edition, Deutscher Verlag für Grundstoffindustrie, 1994, p. 405 et seq.), For example tumble dryers, tumbling drums, drum mixers , Paddle mixer and the like. Monolithic carriers are usually rinsed with the aqueous solutions of the active metal precursor compound.

The solutions used for impregnating are preferably low in halogen, in particular low in chlorine, ie they contain no or less than 500 ppm by weight, in particular less than 100 ppm by weight of halogen, eg 0 to <80 ppm by weight of halogen, based on the total weight of the solution.

The concentration of the active metal precursor compound in the solutions depends of course on the amount of active metal precursor compound to be applied and the absorption capacity of the carrier material for the solution and is <20% by weight, preferably 0.01 to 6% by weight, particularly preferably 0, 1 to 1, 1 wt .-%, based on the total mass of the solution used.

Step (B):

The drying can be carried out by the usual methods of drying solids while maintaining the upper temperature limits mentioned below. The observance of the upper limit of the drying temperatures is for the quality, i. the activity of the catalyst important. Exceeding the drying temperatures given below results in a significant loss of activity. Calcination of the support at higher temperatures, e.g. Above 300 ° C or even 400 ° C, as proposed in the prior art, is not only superfluous but also adversely affects the activity of the catalyst. To achieve adequate drying rates, the drying is preferably carried out at elevated temperature, preferably at <180 ° C, especially at <160 ° C, and at least 40 ° C, especially at least 70 ° C, especially at least 100 ° C, especially in the range of 1 10 ° C to 150 ° C.

The drying of the impregnated with the active metal precursor compound solid is usually carried out under atmospheric pressure and to promote the drying, a reduced pressure can be applied. Frequently, to promote drying, a gas stream will be passed over or through the material to be dried, e.g. Air or nitrogen.

The drying time naturally depends on the desired degree of drying and the drying temperature and is preferably in the range of 1 h to 30 h, preferably in the range of 2 to 10 h. The drying of the treated support material is preferably carried out to such an extent that the content of water or of volatile solvent constituents before the subsequent reduction is less than 5% by weight, in particular not more than 2% by weight, based on the total weight of the solid. The stated proportions by weight in this case relate to the weight loss of the solid, determined at a temperature of 160 ° C., a pressure of 1 bar and a duration of 10 minutes. In this way, the activity of the catalysts used according to the invention can be further increased. Step (C):

The conversion of the solid obtained after drying into its catalytically active form is carried out by reducing the solid at temperatures in the range of generally from 150 ° C. to 450 ° C., preferably from 250 ° C. to 350 ° C., in a manner known per se.

For this purpose, the support material is brought into contact with hydrogen or a mixture of hydrogen and an inert gas at the above-indicated temperatures. The hydrogen absolute pressure is of minor importance for the result of the reduction and can be varied, for example, in the range from 0.2 bar to 1.5 bar. Frequently, the hydrogenation of the catalyst material is carried out at normal hydrogen pressure in the hydrogen stream. Preferably, the reduction is carried out by moving the solid, for example by reducing the solid in a rotary kiln or a rotary kiln. In this way, the activity of the catalysts according to the invention can be further increased. The hydrogen used is preferably free of catalyst poisons, such as CO- and S-containing compounds, eg H ₂ S, COS and others.

The reduction can also be carried out by means of organic reducing reagents such as hydrazine, formaldehyde, formates or acetates.

Subsequent to the reduction, the catalyst can be passivated in a known manner to improve the handling, for example by briefly mixing the catalyst with an oxygen-containing gas, for example air, but preferably with an inert gas mixture containing 1 to 10% by volume of oxygen , treated. Also, C0 ₂ or C0 _{2/02-mixtures} can be applied here. The active catalyst may also be stored under an inert organic solvent, eg ethylene glycol.

For the preparation of the coated catalyst according to the invention, in another embodiment, the active metal catalyst precursor, e.g. as prepared above or prepared as described in WO-A2-02 / 100538 (BASF AG), are impregnated with a solution of one or more alkaline earth metal (II) salts.

Suitable alkaline earth metal (II) salts are corresponding nitrates, in particular magnesium nitrate and calcium nitrate. A suitable solvent for the alkaline earth metal (II) salts in this impregnation step is water. The concentration of the alkaline earth metal (II) salt in the solvent is, for example, 0.01 to 1 mol / liter. Due to the manufacturing process, the active metal is present in the catalysts according to the invention as metallic active metal.

By using halogen-free, especially chlorine-free, active metal precursor compounds and solvents in the preparation of the shell catalyst according to the invention, the halide content, in particular chloride content, of the shell catalysts of the invention is also below 0.05 wt .-% (0 to <500 ppm by weight, eg im Range of 0-400 wppm) based on the total weight of the catalyst. The chloride content is e.g. determined by ion chromatography with the method described below.

In this document, all ppm data are to be understood as parts by weight (ppm by weight), unless stated otherwise.

The support material preferably contains not more than 1% by weight and in particular not more than 0.5% by weight and in particular not more than 0.2% by weight of aluminum oxide, calculated as Al ₂ O ₃ .

Since the condensation of the silica can also be influenced by aluminum and iron, the concentration of Al (III) and Fe (II and / or III) in total is preferably less than 300 ppm, more preferably less than 200 ppm, and is e.g. in the range of 0 to 180 ppm.

The proportion of alkali metal oxide preferably results from the preparation of the support material and can be up to 2 wt .-%. It is preferably less than 1% by weight. Also suitable are alkali metal oxide-free carrier (0 to <0.1 wt .-%). The proportion of MgO, CaO, TiO ₂ or ZrO ₂ can make up to 10 wt .-% of the support material and is preferably not more than 5 wt .-%. Also suitable are support materials which contain no detectable amounts of these metal oxides (0 to <0.1 wt .-%).

Because Al (III) and Fe (II and / or III) can form incorporated acid sites in silica, it is preferred that charge compensation with alkaline earth metal cations (M ²⁺ , M = Be, Mg, Ca, Sr, Ba) in the Carrier is present. This means that the weight ratio of M (II) to (Al (III) + Fe (II and / or III)) is greater than 0.5, preferably> 1, more preferably greater than 3. The Roman numerals in parentheses behind The element symbol indicates the oxidation state of the element. The coated catalyst of the invention is preferably used as a hydrogenation catalyst. It is particularly suitable for the hydrogenation of organic compounds containing at least one hydrogenatable group. The hydrogenatable groups may be groups having the following structural units: CC double bonds, CC triple bonds, aromatic groups, CN double bonds, CN triple bonds, CO double bonds, NO double bonds, CS double bonds, N0 ₂ Groups, wherein the groups may also be contained in polymers or cyclic structures, for. B. in unsaturated heterocycles. The hydrogenatable groups can each occur individually or multiply in the organic compounds. It is also possible that the organic compounds have two or more different of said hydrogenatable groups. Depending on the hydrogenation conditions, it is possible in the last case that only one or more of the hydrogenatable groups are hydrogenated.

Preference is given to using the coated catalysts according to the invention for hydrogenating a carbocyclic aromatic group to the corresponding carbocyclic aliphatic group or for hydrogenating aldehydes to the corresponding alcohols, very particularly preferably for hydrogenating a carbocyclic aromatic group to the corresponding carbocyclic aliphatic group. Particular preference is given to complete hydrogenation of the aromatic group, with complete hydrogenation giving a conversion of the compound to be hydrogenated of generally> 98%, preferably> 99%, more preferably> 99.5%, very particularly preferably> 99.9%, especially> 99.99% and especially> 99.995%.

When using the coated catalyst according to the invention for the hydrogenation of benzene to cyclohexane thus the typical cyclohexane specifications that require a benzene residual content of <100 ppm (equivalent to a benzene conversion of> 99.99%), complied. Preferably, the benzene conversion in a hydrogenation of benzene with the shell catalyst of the invention> 99.995%.

When using the coated catalyst according to the invention for the hydrogenation of aromatic dicarboxylic acid esters, in particular phthalic acid esters to the corresponding dialkylcyclohexanedicarboxylates, the typical specifications which require a residual content of the aromatic dicarboxylic acid ester, in particular residual phthalate content, of <100 ppm (corresponding to a conversion of > 99.99%). Preferably, the conversion in a hydrogenation of aromatic dicarboxylic acid esters, in particular phthalic acid esters, with the coated catalyst according to the invention> 99.995%.

A further subject of the present application is therefore a process for the hydrogenation of an organic compound which comprises at least one hydrogenatable group. preferably, for hydrogenating a carbocyclic aromatic group to the corresponding carbocyclic aliphatic group or for hydrogenating aldehydes to the corresponding alcohols, most preferably for hydrogenating a carbocyclic aromatic group to the corresponding carbocyclic aliphatic group, wherein the organic compound with at least one reducing agent and a shell catalyst according to the invention is brought into contact.

The present invention also relates to the use of the coated catalyst of the invention in a process for the hydrogenation of an organic compound containing at least one hydrogenatable group. Preferably, the present invention relates to this use according to the invention wherein a carbocyclic aromatic group is hydrogenated to the corresponding carbocyclic aliphatic group or aldehydes to the corresponding alcohols. The carbocyclic aromatic group is preferably part of an aromatic hydrocarbon having the following general formula:

(A) - (B) _n wherein the symbols have the following meaning: independently aryl or heteroaryl, preferably A is selected from phenyl, diphenyl, benzyl, dibenzyl, naphthyl, anthracene, pyridyl and quinoline, more preferably A is phenyl;

a number from 0 to 5, preferably 0 to 4, more preferably 0 to 3, especially in the case when A is a 6-membered aryl or heteroaryl ring; in the case where A is a 5-membered aryl or heteroaryl ring, n is preferably 0 to 4; independently of the ring size, n is more preferably 0 to 3, most preferably 0 to 2 and especially 0 to 1; the other carbon atoms or heteroatoms of A carrying no substituents B carry hydrogen atoms or optionally no substituents;

is independently selected from the group consisting of alkyl, alkenyl, alkynyl, substituted alkyl, substituted alkenyl, substituted alkynyl, heteroalkyl, substituted heteroalkyl, heteroalkenyl, substituted heteroalkenyl, heteroalkynyl, substituted heteroalkynyl, cycloalkyl, cycloalkenyl, substituted cycloalkyl, substituted cycloalkenyl, COOR wherein R is H, alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, aryl or substituted aryl, halogen, hydroxy, alkoxy, aryloxy, carbonyl, amino, amido, thio and phosphino; preferably B is independently selected from Ci _-6 alkyl, Ci _-6 alkenyl, Ci _-6 alkynyl, C _3- 8 cycloalkyl, C _3- 8 cycloalkenyl, COOR, where R is H or Ci_i ₂ represents alkyl, Hydroxy, alkoxy, Aryloxy, amino and amido, more preferably B is independently of each other Ci _-6 alkyl, COOR, wherein R is H or Ci-i ₂ alkyl, amino, hydroxy or alkoxy. The expression independently of one another means that when n is 2 or greater, the substituents B may be the same or different radicals from the named groups.

Unless otherwise stated, alkyl according to the present application is to be understood as meaning branched or linear, saturated acyclic hydrocarbon radicals. Examples of suitable alkyl radicals are methyl, ethyl, n-propyl, i-propyl, n-butyl, t-butyl, i-butyl, etc. Preference is given to alkyl radicals having 1 to 50 carbon atoms, particularly preferably 1 to 20 Carbon atoms, most preferably used with 1 to 6 carbon atoms and in particular with 1 to 3 carbon atoms.

In the above-mentioned group COOR R is H or branched or linear alkyl, H or C preferably ₁₂ alkyl. Preferred alkyl groups are C _4-10 -alkyl groups, more preferably C ₈ -10-alkyl groups. These may be branched or unbranched and are preferably branched. The alkyl groups having more than three carbon atoms may be mixtures of isomers of different alkyl groups having the same carbon number. One example is a C ₉ -alkyl group, which may be an isononyl group, ie an isomer mixture of various C ₉ -alkyl groups. The same applies, for example, to a C ₈ -alkyl group. Such isomer mixtures are obtained starting from the alcohols corresponding to the alkyl groups, which are obtained as isomer mixtures on the basis of their preparation process known to the person skilled in the art.

Alkenyl according to the present application is to be understood as meaning branched or unbranched acyclic hydrocarbon radicals which have at least one carbon-carbon double bond. Suitable alkenyl radicals are, for example, 2-propenyl, vinyl, etc. The alkenyl radicals preferably have 2 to 50 carbon atoms, particularly preferably 2 to 20 carbon atoms, very particularly preferably 2 to 6 carbon atoms and in particular 2 to 3 carbon atoms. Furthermore, the term alkenyl is to be understood as meaning those radicals which have either an cis or a trans orientation (alternatively E or Z orientation).

Alkynyl according to the present application is to be understood as meaning branched or unbranched acyclic hydrocarbon radicals which have at least one carbon-carbon triple bond. The alkynyl radicals preferably have 2 to 50 carbon atoms, particularly preferably 2 to 20 carbon atoms, very particularly preferably 1 to 6 carbon atoms and in particular 2 to 3 carbon atoms. Substituted alkyl, substituted alkenyl and substituted alkynyl are alkyl-alkenyl and alkynyl radicals in which one or more hydrogen atoms bound to one carbon atom of these radicals are replaced by another group. Examples of such other groups are heteroatoms, halogen, aryl, substituted aryl, cycloalkyl, cycloalkenyl, substituted cycloalkyl, substituted cycloalkenyl and combinations thereof. Examples of suitable substituted alkyl radicals are benzyl, trifluoromethyl, etc. By the terms heteroalkyl, heteroalkenyl and heteroalkynyl are meant alkyl-alkenyl and alkynyl radicals wherein one or more of the carbon atoms in the carbon chain is selected from N, O and a heteroatom S are replaced.

The bond between the heteroatom and another carbon atom may be saturated or optionally unsaturated.

Cycloalkyl according to the present application is to be understood as meaning saturated cyclic nonaromatic hydrocarbon radicals which are composed of a single ring or several condensed rings. Suitable cycloalkyl radicals are, for example, cyclopentyl, cyclohexyl, cyclooctanyl, bicyclooctyl, etc. The cycloalkyl radicals preferably have between 3 and 50 carbon atoms, particularly preferably between 3 and 20 carbon atoms, very particularly preferably between 3 and 8 carbon atoms and in particular between 3 and 6 carbon atoms. By cycloalkenyl, according to the present application, partially unsaturated, cyclic non-aromatic hydrocarbon radicals are to be understood which have a single or multiple condensed rings. Suitable cycloalkenyl radicals are, for example, cyclopentenyl, cyclohexenyl, cyclooctenyl etc. The cycloalkenyl radicals preferably have 3 to 50 carbon atoms, particularly preferably 3 to 20 carbon atoms, very particularly preferably 3 to 8 carbon atoms and in particular 3 to 6 carbon atoms.

Substituted cycloalkyl and substituted cycloalkenyl radicals are cycloalkyl and cycloalkenyl radicals in which one or more hydrogen atoms of any carbon atom of the carbon ring are replaced by another group. Such other groups are, for example, halogen, alkyl, alkenyl, alkynyl, substituted alkyl, substituted alkenyl, substituted alkynyl, aryl, substituted aryl, cycloalkyl, cycloalkenyl, substituted cycloalkyl, substituted cycloalkenyl, an aliphatic heterocyclic radical, a substituted aliphatic heterocyclic radical, heteroaryl, substituted heteroaryl, alkoxy, aryloxy, boryl, phosphino, amino, silyl, thio, seleno and combinations thereof. Examples of substituted cycloalkyl and cycloalkenyl radicals are 4-dimethylaminocyclohexyl, 4,5-dibromocyclohept-4-enyl and others

For the purposes of the present application, aryl is to be understood as meaning aromatic radicals which have a single aromatic ring or a plurality of aromatic rings which are condensed, linked via a covalent bond or are bonded by a suitable moiety, eg. Example, a methylene or ethylene unit are linked. Such suitable moieties may also be carbonyl moieties, such as in benzophenone, or oxygen moieties, such as in diphenyl ether, or nitrogen moieties, such as in diphenylamine. The aromatic ring or the aromatic rings are, for example, phenyl, naphthyl, diphenyl, diphenyl ether, diphenylamine and benzophenone. The aryl radicals preferably have 6 to 50 carbon atoms, particularly preferably 6 to 20 carbon atoms, very particularly preferably 6 to 8 carbon atoms. Substituted aryl radicals are aryl radicals wherein one or more hydrogen atoms attached to carbon atoms of the aryl radical are replaced by one or more other groups. Other suitable groups include alkyl, alkenyl, alkynyl, substituted alkyl, substituted alkenyl, substituted alkynyl, cycloalkyl, cycloalkenyl, substituted cycloalkyl, substituted cycloalkenyl, heterocyclo, substituted heterocyclo, halogen, halo-substituted alkyl (e.g., CF ₃ ), hydroxy, amino , Phosphino, alkoxy, thio and both saturated and unsaturated cyclic hydrocarbons, which may be fused to the aromatic ring or to the aromatic rings or may be linked by a bond, or may be linked to one another via a suitable group. Suitable groups have already been mentioned above.

Heteroaryl radicals are to be understood as those aryl radicals in which one or more of the carbon atoms of the aromatic ring of the aryl radical has been replaced by a heteroatom selected from N, O and S.

Substituted heteroaryl radicals are understood as meaning those substituted aryl radicals in which one or more of the carbon atoms of the aromatic ring of the substituted aryl radical has been replaced by a heteroatom selected from N, O and S.

Heterocyclo according to the present application means a saturated, partially unsaturated or unsaturated cyclic radical in which one or more carbon atoms of the radical are represented by a heteroatom, e.g. N, O or S are substituted (the term "heterocyclo" also includes the abovementioned heteroaryl radicals.) Examples of heterocyclo radicals are piperazinyl, morpholinyl, tetrahydropyranyl, Tetrahydrofuranyl, piperidinyl, pyrrolidinyl, oxazolinyl, pyridyl, pyrazyl, pyridazyl, pyrimidyl.

Substituted heterocyclo radicals are those heterocyclo radicals in which one or more hydrogen atoms which are bonded to one of the ring atoms are replaced by another group. Other suitable groups include halogen, alkyl, substituted alkyl, aryl, substituted aryl, heteroaryl, substituted heteroaryl, alkoxy, aryloxy, boryl, phosphino, amino, silyl, thio, seleno, and combinations thereof. Alkoxy radicals are radicals of the general formula -OZ ¹ , where Z ^{1 is} selected from alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, heterocycloalkyl, substituted heterocycloalkyl, silyl and combinations thereof. Suitable alkoxy radicals are, for example, methoxy, ethoxy, benzyloxy, t-butoxy, etc. The term aryloxy means those radicals of the general formula -OZ ¹ , wherein Z ^{1 is} selected from aryl, substituted aryl, heteroaryl, substituted heteroaryl and Combinations of it. Suitable aryloxy groups are phenoxy, substituted phenoxy, 2-pyridinoxy, 8-quinolinoxy, etc. In a preferred embodiment, A is phenyl, n is 0 to 3 and B Ci _-6 alkyl, COOR, where R is H or C i ₂ alkyl , Amino, hydroxy or alkoxy. The hydrogenation process according to the invention is preferably carried out in such a way that the phenyl group is completely hydrogenated to the corresponding cyclohexyl group. Preferred compounds which are hydrogenated according to the invention to their corresponding cyclohexyl derivatives are mentioned below.

In a preferred embodiment of the hydrogenation process according to the invention, the aromatic hydrocarbon is selected from the group consisting of benzene and alkyl-substituted benzenes such as toluene, ethylbenzene, xylene (mixture of o, m, p or isomers) and mesitylol (1, 2,4 or 1, 3,5 or mixture of isomers). Thus, in the process of the invention, benzene is preferably hydrogenated to cyclohexane and the alkyl-substituted benzenes such as toluene, ethylbenzene, xylene and mesitylol to alkyl-substituted cyclohexanes such as methylcyclohexane, ethylcyclohexane, dimethylcyclohexane and trimethylcyclohexane. It is also possible to hydrogenate any desired mixtures of the aforementioned aromatic hydrocarbons to mixtures of the corresponding cyclohexanes. For example, any mixtures containing two or three compounds selected from benzene, toluene and xylene can be hydrogenated to mixtures containing two or three compounds selected from cyclohexane, methylcyclohexane and dimethylcyclohexane. In a further preferred embodiment of the hydrogenation process according to the invention, the aromatic hydrocarbon is selected from the group consisting of phenol, alkyl-substituted phenols such as 4-tert-butylphenol and 4-nonylphenol, bis (p-hydroxyphenyl) methane and bis (p-hydroxyphenyl ) dimethyl methane. Thus, phenol to cyclohexanol, the alkyl-substituted phenols such as 4-tert-butylphenol and 4-nonylphenol, to alkyl-substituted cyclohexanols such as 4-tert-butylcyclohexanol and 4-nonylcyclohexanol, bis (p-hydroxyphenyl) methane to bis in the inventive method are preferred (p-hydroxycyclohexyl) methane and bis (p-hydroxyphenyl) dimethylmethane hydrogenated to bis (p-hydroxycyclohexyl) dimethylmethane.

In a further preferred embodiment of the hydrogenation process according to the invention, the aromatic hydrocarbon is selected from the group consisting of aniline, alkyl-substituted aniline, Ν, Ν-dialkylaniline, diaminobenzene, bis (p-aminophenyl) methane and bis (p-aminotolyl) methane. In the process according to the invention are thus preferably aniline to cyclohexylamine, alkyl-substituted aniline to alkyl-substituted cyclohexylamine, Ν, Ν-dialkylaniline to N, N-dialkylcyclohexylamine, diaminobenzene to diaminocyclohexane, bis (p-aminophenyl) methane to bis (p-aminocyclohexyl) methane and bis (p-aminotolyl) methane hydrogenated to bis (p-amino-methylcyclohexyl) methane.

In a further preferred embodiment of the hydrogenation according to the invention the aromatic hydrocarbon is selected from the group consisting of aromatic carboxylic acids such as phthalic acid and aromatic Carbonsäureestern such as C i ₂ alkyl esters of phthalic acid, wherein said _Ci-i2 alkyl radicals may be linear or branched, for example, dimethyl phthalate, di-2-propylheptylphthalate, di-2-ethylhexyl phthalate, dioctyl phthalate, diisononyl phthalate. In the method according to the invention are thus preferably aromatic carboxylic acids such as phthalic to cycloaliphatic carboxylic acids such as tetrahydrophthalic acid and aromatic carboxylic acid esters such as Ci-i ₂ alkyl esters of phthalic to aliphatic carboxylic acid esters such as C-12-alkyl esters of tetrahydrophthalic eg dimethyl phthalate to Dimethylcyclohexandicarboxylat, di-2-propylheptylphthalat to di-2-propylheptylcyclohexandicarboxylat, di-2-ethylhexylphthalat to di-2-ethylhexylcyclo-hexanedicarboxylate, dioctyl phthalate to Dioctylcyclohexandicarboxylat and diisononyl phthalate to diisononyl-cyclohexanedicarboxylate, hydrogenated.

Very particular preference is given in the process according to the invention to the organic compound which has at least one carbocyclic aromatic group selected from the group consisting of benzene, alkyl-substituted benzenes, phenol, alkyl-substituted phenols, aniline, alkyl-substituted aniline, N, N-dialkylaniline, Diaminobenzene, bis (p-aminophenyl) methane, bis (p-aminotolyl) methane, aromatic carboxylic acids, aromatic carboxylic esters and mixtures thereof.

Particularly preferred is the organic compound which comprises at least one organic compound which has at least one carboelomatic aromatic group selected from the group consisting of benzene, diisononyl phthalate, benzoic acid, 2-methylphenol, bisphenol A, cuminaldehyde, aniline, methylenedianiline, ortho Toluidine base, xylidine base and mixtures thereof. In a further embodiment, the present application relates to a process for the hydrogenation of aldehydes to the corresponding alcohols. Preferred aldehydes are mono- and disaccharides such as glucose, lactose and xylose. The mono- and disaccharides are hydrogenated to the corresponding sugar alcohols, e.g. glucose is hydrogenated to sorbitol, lactose to lactitol and xylose to xylitol.

Suitable mono- and disaccharides and suitable hydrogenation conditions are, for. As disclosed in DE-A 101 28 205, wherein instead of the catalyst disclosed in DE-A 101 28 205, the coated catalyst according to the present invention is used. The hydrogenation process according to the invention is a selective process for the hydrogenation of organic compounds containing hydrogenatable groups, preferably for the hydrogenation of a carbocyclic aromatic group to the corresponding carbocyclic aliphatic group, with high yields and space-time yields, [product amount / (catalyst volume · time) ] (kg / (l _Ka t · h)), [ _{amount of} product / (reactor volume · time)] (kg / (l _reac tor · h)), based on the catalyst used and in which the Catalysts without workup can be used several times for hydrogenations. In particular, long catalyst life times are achieved in the hydrogenation process according to the invention. The hydrogenation process according to the invention can be carried out in the liquid phase or in the gas phase. The hydrogenation process according to the invention is preferably carried out in the liquid phase.

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

Any suitable solvent or diluent may be used as solvent or diluent. The solvents or diluents are basically additionally those which are capable of dissolving as completely as possible the organic compound to be hydrogenated or which are completely mixed with it and which are inert under the hydrogenation conditions, ie are not hydrogenated. Examples of suitable solvents are cyclic and acyclic ethers, for example tetrahydrofuran, dioxane, methyl tert-butyl ether, dimethoxyethane, dimethoxypropane, dimethyldiethylene glycol, aliphatic alcohols such as methanol, ethanol, n- or isopropanol, n-, 2-, iso- or tert Butanol, carboxylic acid esters such as methyl acetate, ethyl acetate, propyl acetate or butyl acetate, and aliphatic Etheralkohole such as methoxypropanol and cycloaliphatic compounds such as cyclohexane, methylcyclohexane and dimethylcyclohexane.

The amount of solvent or diluent used is not particularly limited and can be freely selected as needed, but those amounts are preferred which lead to a 3 to 70 wt .-% solution of the organic compound intended for hydrogenation. The use of a diluent is advantageous in order to avoid excessive heat of reaction in the hydrogenation process. Excessive heat of reaction can lead to deactivation of the catalyst and is therefore undesirable. Therefore, careful temperature control is useful in the hydrogenation process of the present invention. Suitable hydrogenation temperatures are mentioned below.

When using a solvent, in the context of the process according to the invention, the product formed during the hydrogenation, that is to say preferably the one or more cycloaliphatic compounds, is preferably used as solvent, optionally in addition to other solvents or diluents. In any case, a part of the product formed in the process can be admixed with the aromatic still to be hydrogenated. In the hydrogenation of benzene, cyclohexane is thus used as solvent in a particularly preferred embodiment. In the hydrogenation of phthalates, the corresponding cyclohexanedicarboxylic acid dialkyl esters are preferably used as solvent.

Based on the weight of the intended for the hydrogenation organic compound is preferably 1 to 30 times, more preferably 5 to 20 times, in particular 5 to 10 times the amount of product as a solvent or diluent admixed. In particular, the present invention relates to a hydrogenation of the type in question, wherein benzene is hydrogenated in the presence of the catalyst according to the invention to cyclohexane.

The actual hydrogenation is usually carried out in analogy to the known hydrogenation for the hydrogenation of organic compounds, the hydrogenatable groups preferably for the hydrogenation of a carbocyclic aromatic group to the corresponding carbocyclic aliphatic group, as described in the aforementioned prior art. For this purpose, the organic compound is brought into contact as liquid phase or gas phase, preferably as liquid phase, with the catalyst in the presence of hydrogen. The liquid phase can be passed through a fluid catalytic bed (fluid bed mode) or a fixed catalyst bed (fixed bed mode).

The present invention therefore preferably relates to the process according to the invention. wherein the hydrogenation is carried out in a fixed bed reactor.

The hydrogenation can be configured both continuously and discontinuously, wherein the continuous process procedure is preferred. Preferably, the process according to the invention is carried out in trickle-bed reactors or in flooded mode according to the fixed-bed procedure. The hydrogen can be passed both in cocurrent with the solution of the educt to be hydrogenated and in countercurrent over the catalyst.

Suitable apparatus for carrying out hydrogenation after hydrogenation on the catalyst fluidized bed and on the fixed catalyst bed are known in the art, e.g. from Ullmanns Enzyklopadie der Technischen Chemie, 4th Edition, Vol. 13, p. 135 ff., and P.N. Rylander, "Hydrogenation and Dehydrogenation" in Ulmann's Encyclopedia of Industrial Chemistry, 5th ed. on CD-ROM. The hydrogenation according to the invention can be carried out both at normal hydrogen pressure and at elevated hydrogen pressure, e.g. be carried out at a hydrogen absolute pressure of at least 1, 1 bar, preferably at least 2 bar. In general, the absolute hydrogen pressure will not exceed 325 bar, preferably 300 bar. The hydrogen absolute pressure is particularly preferably in the range from 1.1 to 300 bar, very particularly preferably in the range from 5 to 40 bar. The hydrogenation of benzene occurs e.g. at a hydrogen pressure of generally <50 bar, preferably 10 bar to 45 bar, particularly preferably 15 to 40 bar.

The reaction temperatures in the process according to the invention are generally at least 30.degree. C. and frequently will not exceed 250.degree. The hydrogenation process is preferably carried out at temperatures in the range from 50 to 200.degree. C., particularly preferably from 70 to 180.degree. C., and very particularly preferably in the range from 80 to 160.degree. The hydrogenation of benzene is carried out, for example, at temperatures in the range of generally from 75 ° C to 170 ° C, preferably from 80 ° C to 160 ° C. Hydrogen-containing gases which contain no catalyst poisons such as carbon monoxide or sulfur-containing gases such as H ₂ S or COS, eg. As mixtures of hydrogen with inert gases such as nitrogen or reformer exhaust gases, which usually still contain volatile hydrocarbons. Preference is given to using pure hydrogen (purity> 99.9% by volume, especially> 99.95% by volume, in particular> 99.99% by volume).

Due to the high catalyst activity requires relatively small amounts of catalyst based on the reactant. Thus, in the case of the discontinuous suspension procedure, preference is given to using less than 5 mol%, for example from 0.2 mol% to 2 mol%, of active metal, based on 1 mol of educt. In a continuous embodiment of the hydrogenation process is usually the starting material to be hydrogenated in an amount of 0.05 to 3 kg / (l (catalyst) ^« h), in particular 0.15 to 2 kg / (l (catalyst) ^« h) on lead the catalyst.

Of course, the catalysts used in this process can be regenerated with decreasing activity according to the usual for noble metal catalysts such as ruthenium catalysts, known in the art methods. Here are e.g. the treatment of the catalyst with oxygen as described in BE 882 279, the treatment with dilute, halogen-free mineral acids as described in US 4,072,628, or the treatment with hydrogen peroxide, for. B. in the form of aqueous solutions containing from 0.1 to 35 wt .-%, or treatment with other oxidizing substances, preferably in the form of halogen-free solutions. Usually, the catalyst after reactivation and before re-use with a solvent, for. As water, rinse.

The hydrogenation-containing organic compounds (preferred compounds mentioned above) used in the hydrogenation process according to the invention in a preferred embodiment of the process according to the invention have a sulfur content of generally <2 mg / kg, preferably <1 mg / kg, more preferably <0 , 5 mg / kg, most preferably <0.2 mg / kg, and especially <0.1 mg / kg. The method for determining the sulfur content is mentioned below. A sulfur content of <0.1 mg / kg means that no sulfur in the feedstock such as e.g. Benzene is detected.

The hydrogenation process according to the invention is preferably characterized in the case of the preferred hydrogenation of carbocyclic aromatic groups to the corresponding carbocyclic aliphatic groups by the complete hydrogenation of the aromatic nuclei of the organic compounds with carbocyclic aromatic groups, the degree of hydrogenation generally being> 98%, preferably at> 99%, particularly preferably> 99.5%, very particularly preferably> 99.9%, in particular> 99.99% and especially> 99.995%.

The degree of hydrogenation is determined by gas chromatography. In the case of the hydrogenation of dicarboxylic acids or dicarboxylic acid esters, in particular phthalates, the degree of hydrogenation is determined by means of UVA / IS spectrometry.

A particularly preferred embodiment of the hydrogenation process according to the invention relates to the hydrogenation of benzene to cyclohexane. The hydrogenation process according to the invention is therefore described in more detail below using the example of benzene hydrogenation.

The hydrogenation of benzene is generally in the liquid phase. It can be carried out continuously or discontinuously, continuous operation being preferred.

The benzene hydrogenation according to the invention is generally carried out at a temperature of 75 ° C to 170 ° C, preferably 80 ° C to 160 ° C. The pressure is generally <50 bar, preferably 10 to 45 bar, more preferably 15 to 40 bar, most preferably 18 to 38 bar.

The benzene used in the hydrogenation process according to the invention in a preferred embodiment of the method according to the invention has a sulfur content of generally <2 mg / kg, preferably <1 mg / kg, more preferably <0.5 mg / kg, most preferably <0.2 mg / kg, and in particular <0.1 mg / kg. The method for determining the sulfur content is mentioned below. A sulfur content of <0.1 mg / kg means that no sulfur is detected in benzene using the method of measurement given below. The hydrogenation may generally be carried out in the fluid bed or fixed bed mode, with preference being given to carrying out in the fixed bed mode. The hydrogenation process according to the invention is particularly preferably carried out with liquid circulation, wherein the hydrogenation heat can be removed and used via a heat exchanger. When the hydrogenation process according to the invention is carried out with liquid circulation, the feed / circulation ratio is generally from 1: 5 to 1:40, preferably from 1:10 to 1:30.

In order to achieve complete conversion, an after-reaction of the hydrogenation can take place. For this purpose, the hydrogenation discharge following the hydrogenation process according to the invention in the gas phase or in the liquid phase in the straight pass, by a be passed downstream reactor. The reactor can be operated with liquid phase hydrogenation in trickle mode or flooded. The reactor is filled with the catalyst according to the invention or with another catalyst known to the person skilled in the art.

Hydrogenated products can thus be obtained with the aid of the process according to the invention which contain no or very low residual contents of the starting materials to be hydrogenated.

Examples

Example 1: Catalyst Preparation Example 1.1 (Inventive)

Si0 ₂ support AF125, spheres 3-5 mm, BET 337 m ² / g, shaking density 0.49 kg / l, water absorption (WA) = 0.83 ml / g, and ruthenium (III) acetate in acetic acid of Umicore 200 g carrier is presented in a round bottom flask. 14.25% Ru acetate solution. is weighed into a measuring cylinder and with dist. H ₂ 0 diluted to 150 ml (90% WA). The solution is quartered. The support material is placed on a rotary evaporator and the first of the four impregnations is pumped onto the support material with a slight vacuum at 3-6 rpm. After the first impregnation is on the support, it is further rotated in a rotary evaporator for 10 min to homogenize the catalyst. This step is then repeated three more times until the entire solution is on the support. The impregnated material is dried in a rotary kiln at 140 ° C, reduced 3h / 200 ° C (20 l / h H ₂ , 10 l / h N ₂ ) and passivated (at RT (5% air in N ₂ , 2h)). The novel catalyst A thus obtained contains 0.34% by weight of Ru

Example 1 .2 (comparative example)

Catalyst B is prepared as described in WO 2006/136451, (0.35% Ru / Si0 ₂ )

Example 1 .3 (comparative example)

Catalyst C is prepared as described in EP 1 042 273 (0.5% Ru / Al ₂ O ₃ ) Example 2: Hydrogenation Examples Example 2.1: Hydrogenation of benzene

3.4 g of the catalyst A prepared according to Example 1.1 Span in a catalyst insert basket are placed in a 300 ml pressure reactor and admixed with 100 g of a 5% strength solution of benzene in cyclohexane. The hydrogenation is carried out with pure hydrogen at a constant pressure of 32 bar and a temperature of 100.degree. It is hydrogenated for 4h The reactor is then relaxed. Sales is 100%.

Example 2.2: Hydrogenation of Benzene with Catalyst B

In a 300 mL pressure reactor, 2.5 g of the according to Example 1 .2. prepared catalyst B in a catalyst insert basket and treated with 100 g of a 5% solution of benzene in cyclohexane. The hydrogenation is carried out with pure hydrogen at a constant pressure of 32 bar and a temperature of 100 ° C. It is hydrogenated for 4 h The reactor was then relaxed. Sales amounted to 99.2%.

Example 2.3 Hydrogenation of diisononyl phthalate to diisononylcyclohexanedicarboxylic acid ester (DINCH):

A continuously operated plant consisting of two tubular reactors connected in series (main reactor (HR) 160 mL and postreactor (NR) 100 mL) is treated with the same procedure described in Example 1 .1. prepared catalyst A (HR: 54.3 g, NR: 33.5 g). The main reactor is operated in trickle mode with circulation, the secondary reactor in straight pass in the swamp mode. Palatinol N (diisononyl phthalate, CAS No. 28553-12-0, prepared according to Example 3) (36 g / h, cat load = 0.3 kg / (L * h)) is treated with pure hydrogen at a mean temperature of 122 ° C in the main reactor and 122 ° C in the post-reactor and a constant pressure of 36 bar pumped through the reactor cascade. The conversion of palatinol N is 100%, the selectivity based on DINCH is 99.5%. The cis / trans ratio is 94 / 6-92 / 8.

Example 2.4: Hydrogenation of diisononyl phthalate to di-isononylcyclohexanedicarboxylic acid ester (DINCH) with catalyst C

A continuously operated plant consisting of a tubular reactor (160 ml) is treated with the catalyst C prepared in Example 1 .3 (0.5% Ru on Al ₂ O ₃ ) (78.0 g). filled. The reactor is operated in trickle mode with circulation (liquid load 10 m / h). Palatinol N (diisononyl phthalate, CAS No. 28553-12-0, prepared according to Example 3) (36 g / h, cat load = 0.3 kg / (l_xh)) is treated with pure hydrogen at an average temperature of 132 ° C constant pressure of 40 bar pumped through the reactor. The conversion of palatinol N is 94.9%, the selectivity based on DINCH is 98.5%. The cis / trans ratio is 96 / 4-90 / 10.

Example 2.5: Nuclear Hydrogenation DOTP (dioctyltetephthalate)

In a 300 ml_ pressure reactor with the according to Example 1 .1. (7.5 g) prepared catalyst A in a catalyst insert basket and treated with 150 g Dioctyltetephthalat. The hydrogenation is carried out with pure hydrogen at a constant pressure of 200 bar and a temperature of 120 ° C. It is hydrogenated for 12 h The reactor is then relaxed. The turnover is 100%. (GC column: optimal, length 30 m, layer thickness 1 μηη, temperature program: 50 ° C, 10 min, with 10C / min to 300 ° C) The selectivity for 1, 4-Cyclohexandicarbonsäuredioctylester is 97.7% as a mixture of ice and transisomers.

Example 2.6: Nuclear Hydrogenation DOTP (Dioctyltetephthalate) with Catalyst C

In a 300 ml pressure reactor, 10 g of the catalyst C prepared according to Example 1 .3 are placed in a catalyst insert basket and admixed with 150 g of dioctyl terephthalate. The hydrogenation is carried out with pure hydrogen at a constant pressure of 200 bar and a temperature of 120 ° C. It is hydrogenated for 12 h. The reactor is subsequently expanded. The turnover is 100%. (GC column: optimal, length 30 m, layer thickness 1 μηη, temperature program: 50 ° C, 10min, with 10C / min to 300 ° C) The selectivity for 1, 4-Cyclohexandicarbonsäuredioctylester is 97.2% as a mixture of ice and trans isomers.

Example 2.7: Hydrogenation of benzoic acid

In a 300 mL pressure reactor, 3 g of the catalyst A prepared according to Example 1 .1 are initially charged in a catalyst insert basket and mixed with 48 g of benzoic acid dissolved in 72 g of THF (40% by weight). The hydrogenation is carried out with pure hydrogen at a constant pressure of 200 bar and a temperature of 150 ° C (20 hours). The reactor is subsequently expanded. The conversion of benzoic acid is 100% (GC column: PB-FFAP, length 25 m, layer thickness 0.25 μm, temperature program: from 40 ° C. with 5 ° C./min to 230 ° C.). The selectivity Cyclohexanecarboxylic acid is 95% by volume. As minor components about 5 FI .-% low boilers (components with a lower boiling point than cyclohexane carboxylic acid) can be detected.

Example 2.8: Hydrogenation of 2-methylphenol to 2-methylcyclohexanol

In a 300 ml pressure reactor, 5 g of the catalyst A prepared according to Example 1 .1 are introduced into a catalyst insert basket and treated with 180 ml of a 25% strength solution of ortho-cresol (2-methyl-phenol) in THF. The hydrogenation is carried out with pure hydrogen at a constant pressure of 200 bar and a temperature of 100 ° C. It is hydrogenated until hydrogen is no longer absorbed (10 hours). The reactor is subsequently expanded. The conversion of ortho-cresol is 100%. The selectivity to cis / trans-2-methylcyclohexanol is 98.6%. The cis / trans ratio of the obtained 2-methylcyclohexanol is 1.59: 1.

Example 2.9: Hydrogenation of bisphenol A 3.6 g of the catalyst A prepared according to Example 1 .1 are placed in a 300 ml pressure reactor and placed in a catalyst insert basket, and 100 g of a 30% strength solution of bisphenol A in n-butanol are added. The hydrogenation is carried out with pure hydrogen at a constant pressure of 200 bar and a temperature of 180 ° C. It is hydrogenated for 24 h. The reactor is subsequently expanded. The conversion of bisphenol A is 100% (GC column: RTX 65, length 30 m, layer thickness 0.5 μm, temperature program: from 280 ° C. 40 minutes isothermal). The selectivity of ring hydrogenated bisphenol A is 85.77 FI .-%. As minor components about 14.23 FI .-% low boilers (components with a lower boiling point than ring hydrogenated bisphenol A) can be detected.

Example 2.10: Hydrogenation of Cuminaldehyde to Isopropylcyclohexylmethanol

In a 300 mL pressure reactor, 3.5 g of the catalyst A prepared according to Example 1.1 are placed in a catalyst insert basket and mixed with 100 g Cuminaldehyd. The hydrogenation is carried out with pure hydrogen at a constant pressure of 200 bar and a temperature of 160 ° C. It is hydrogenated until hydrogen is no longer absorbed (20 hours). The reactor is subsequently expanded. The conversion of cuminaldehyde is 100% (GC column: DB wax, length 30 m, layer thickness 0.25 μm, temperature program: from 60 ° C at 2.5 ° C / min to 240 ° C). The selectivity to isopropylcyclohexylmethanol is 83.2 FI .-%. When Secondary components can be detected about 15 FI .-% low boilers (components with a lower boiling point than isopropylcyclohexanol). Example 2.1 1: Hydrogenation of Cuminaldehyde with Catalyst B

In a 300 ml pressure reactor, 3.5 g of the catalyst B prepared according to Example 1.2 are placed in a catalyst insert basket and mixed with 100 g of cuminaldehyde. The hydrogenation is carried out with pure hydrogen at a constant pressure of 200 bar and a temperature of 160 ° C. It is hydrogenated until hydrogen is no longer absorbed (20 hours). The reactor is subsequently expanded. The conversion of cuminaldehyde is 100% (GC column: DB wax, length 30 m, layer thickness 0.25 μm, temperature program: from 60 ° C at 2.5 ° C / min to 240 ° C). The selectivity to isopropylcyclohexylmethanol is 60.6 FI .-%. As minor components about 30.5 FI .-% low boilers (components with a lower boiling point than isopropylcyclohexanol) can be detected.

Example 2.12: Hydrogenation of Aniline to Cyclohexylamine

In a 300 mL pressure reactor, 2.9 g of catalyst A prepared according to Example 1.1 are placed in a catalyst insert basket and treated with 150 g of a 10% solution of aniline in cyclohexylamine. The hydrogenation is carried out with pure hydrogen at a constant pressure of 200 bar and a temperature of 160 ° C. It is hydrogenated for 3 h. The reactor is subsequently expanded. The conversion of aniline is> 99.9% (GC column: RTX-35-amines, length 30 m, layer thickness 1, 5 μηη, temperature program: from 100 ° C at 20 ° C / min to 280 ° C, 15 min isothermal). Example 2.13: Hydrogenation of MDA to Dicykan

In a 0.3 L pressure reactor 1, 2 g of the catalyst prepared according to Example 1.1 A are placed in a catalyst insert basket and treated with 100 g of a 10% solution of MDA (4,4'-methylenedianiline) in dioxane. The hydrogenation is carried out with pure hydrogen at a constant pressure of 200 bar and a temperature of 220 ° C. It was hydrogenated for 10 h. The reactor is subsequently expanded. The conversion of MDA amounts to 98.4% (GC column: RTX 35, length 30 m, layer thickness 0.5 μm, temperature program: from 100 ° C at 5 ° C / min to 160 ° C, from 160 ° C to 2 ° C / min to 250 ° C). The selectivity to dicyan (4,4 - methylene (diaminocyclohexane) is 88 FI .-%. Example 2.14: Hydrogenation of ortho-toluidine base to dimethyl dicykan

In a 300 ml pressure reactor, 1, 2 g of the catalyst prepared according to Example 1.1 A are placed in a catalyst insert basket and with 160 g of a 12% solution of ortho-Toluidinbase (2,2'-dimethyl-4,4 The hydrogenation is carried out with pure hydrogen at a constant pressure of 200 bar and a temperature of 220 ° C. It is hydrogenated for 8 hours and then the reactor is let down. Toluidine base is 100% (GC column: DB-1, length 30 m, layer thickness 1 μηη, temperature program: from 150 ° C at 8 ° C / min to 280 ° C.) The selectivity of dimethyldicykan (2,2'-dimethyl -4,4'-methylenebis (cyclohexylamine) is 89.1% by FI. Example 2.15: Hydrogenation of ortho-toluidine base to dimethyl dicycane with catalyst C

In a 300 mL pressure reactor, 0.8 g of the according to Example 1 .3. prepared catalyst C in a catalyst insert basket and with 160 g of a 12% solution of ortho-Toluidinbase (2,2'-dimethyl-4,4'-methylenbis (aniline) in THF.) The hydrogenation with pure hydrogen at a constant pressure of 200 bar and a temperature of 220 ° C. It is hydrogenated for 8 hours and then the reactor is let down The conversion of o-toluidine base is 100% (GC column: DB-1, length 30 m Temperature range: from 150 ° C at 8 ° C / min to 280 ° C.) The selectivity to dimethyldicykan (2,2'-dimethyl-4,4'-methylenebis (cyclohexylamine) is 86.8 FI. -%.

Example 2.16: Hydrogenation of xylidine base to tetradimethyldicykan

In a 1.2 L pressure reactor, 5 g of the catalyst A prepared according to Example 1.1 are placed in a catalyst insert basket and treated with 700 g of a 25% solution of xylidine base (2,2 ', 6,6'-tetremethyl-4,4 The hydrogenation is carried out with pure hydrogen at a constant pressure of 200 bar and a temperature of 220 ° C. It is hydrogenated for 2 hours and then the reactor is let down. The conversion of xylidine base is 100 % (GC column: DB1, length 30 m, layer thickness 0.25 μm, temperature program: from 150 ° C. at 8 ° C./min to 280 ° C.) The selectivity to tetramethyldicykan (2.2 ', 6.6') -Tetramethyl-4,4'-methylenebis (cyclohexylamine) is 89 FI .-%. Example 2.17: Hydrogenation of xylidine base to tetradimethyldicykan with catalyst C

In a 3.5 L pressure reactor, 100 g of the catalyst prepared according to Example 1.3 C are placed in a catalyst basket and with 2000 g of a 25% solution of xylidine base (2,2 ', 6,6'-tetramethyl-4,4 The hydrogenation is carried out with pure hydrogen at a constant pressure of 200 bar and a temperature of 230 ° C. The mixture is hydrogenated for 2 hours and then the reactor is let down The conversion of xylidine base is 100 % (GC column: DB1, length 30 m, layer thickness 0.25 μm, temperature program: from 150 ° C. at 8 ° C./min to 280 ° C.) The average selectivity of five batches for tetramethyldicykan (2.2 ', 6,6'-Tetramethyl-4,4'-methylenebis (cyclohexylamine) is 76% by weight. Example 2.18: Hydrogenation of bisphenol A

In a 300 mL pressure reactor, 3.6 g of the catalyst A prepared according to Example 1.1 are placed in a catalyst insert basket and treated with 100 g of a 30% solution of bisphenol A in n-butanol. The hydrogenation is carried out with pure hydrogen at a constant pressure of 200 bar and a temperature of 180.degree. It is hydrogenated for 16 h. The reactor is subsequently expanded. The conversion of bisphenol A is 100% (GC column: RTX 65, length 30 m, layer thickness 0.5 μηη, temperature program: from 280 ° C 40 min isothermal). The selectivity of ring hydrogenated bisphenol A is 87.5 FI .-%. As minor components about 7.4 FI .-% low boilers (components with a lower boiling point than ring hydrogenated bisphenol A) can be detected.

Example 3: Preparation of palatinol N (diisononyl phatalate)

Process step 1 (butene dimerization):

The butene dimerization is carried out continuously in an adiabatic reactor consisting of two partial reactors (length: 4 m each, diameter: 80 cm each) with intermediate cooling at 30 bar. The feedstock used is a raffinate II having the following composition: i-butane: 2% by weight

n-butane: 10% by weight

i-butene: 2% by weight

Butene-1: 32% by weight

Butene-2-trans: 37% by weight

Butene-2-cis: 17% by weight The catalyst used is a material according to DE 4 339 713 consisting of 50 wt .-% NiO, 12.5 wt .-% Ti0 ₂ , 33.5 wt .-% Si0 ₂ and 4 wt .-% Al ₂ 0 ₃ in the form of 5x5 mm tablets. The reaction is carried out at a rate of 0.375 kg of raffinate II / l of catalyst ^* h, a recycle C ₄ / raffinate II of 3, an inlet temperature on the 1. Sub-reactor of 38 ° C and an inlet temperature of the second partial reactor of 60 ° C carried out. The conversion based on the butenes contained in the raffinate II is 83.1%; the selectivity to the desired octenes was 83.3%. By fractional distillation of the reactor effluent, the octene fraction is separated from unreacted raffinate II and the high boilers.

Process step 2 (hydroformylation and subsequent hydrogenation): 750 g of the octene mixture prepared in process step 1 are charged discontinuously in an autoclave with 0.13 wt .-% Dikobaltoktacarbonyl Co ₂ (CO) ₈ as a catalyst with the addition of 75 g of water at 185 ° C and reacted under a synthesis gas pressure of 280 bar at a mixing ratio of H ₂ to CO of 60/40 5 hours. The consumption of synthesis gas, to recognize a pressure drop in the autoclave is supplemented by repressing. After the autoclave has been decompressed, the reaction effluent is freed from the cobalt catalyst with 10% by weight acetic acid by passing in air, and the organic product phase is hydrogenated with Raney nickel at 125 ° C. and a hydrogen pressure of 280 bar for 10 h. By fractional distillation of the reaction output, the isononanol fraction is separated from the C8 paraffins and the high boilers.

Process step 3 (esterification): In the third process step, 865.74 g of the isononanol fraction obtained in process step 2 (20% excess with respect to phthalic anhydride) with 370.30 g of phthalic anhydride and 0.42 g of isopropyl butyl titanate as catalyst in a 2 l autoclave under N ₂ -einperlung (10 l / h) reacted at a stirring speed of 500 U / min and a reaction temperature of 230 ° C. The reaction water formed is continuously removed from the reaction mixture with the N ₂ stream. The reaction time is 180 min. Subsequently, the excess isononanol is distilled off at a vacuum of 50 mbar. 1000 g of crude diisononyl phthalate are neutralized with 150 ml of 0.5% sodium hydroxide solution by stirring at 80 ° C for 10 minutes. A two-phase mixture is formed with an upper organic phase and a lower aqueous phase (hydrolyzed catalyst waste liquor). The aqueous phase is separated off and the organic phase is washed twice with 200 ml H ₂ 0. For further purification, the neutralized and washed diisononyl phthalate with Steam steamed at 180 ° C and 50 mbar vacuum for 2 h. The purified diisononyl phthalate is then dried for 30 minutes at 150 ° C / 50 mbar by passing an N ₂ - stream (2 l / h), then stirred with activated charcoal for 5 min and suction filtered through a suction filter with filter aid Supra-Theorit 5 (temperature 80 ° C).

The diisononyl phthalate thus obtained has a density of 0.973 g / cm ³ , a viscosity of 73.0 mPa ^* s, a refractive index n _D ²⁰ of 1.4853, an acid number of 0.03 mg KOH / g, a water content of 0, 03% and GC purity of 99.83%.

Claims

claims

1 . A coated catalyst containing an active metal selected from the group consisting of ruthenium, rhodium, palladium, platinum and mixtures thereof, applied to a support material comprising silicon dioxide, characterized in that the pore volume of the support material 0.6 to 1, 0 ml / g, determined by Hg porosimetry, the BET surface area is 280 to 500 m ² / g, and at least 90% of the pores present have a diameter of 6 to 12 nm.

2. coated catalyst according to claim 1, characterized in that the amount of the active metal 0.1 to 0.5 wt .-%, based on the total coated catalyst is.

3. coated catalyst according to claim 1 or 2, characterized in that the dispersity of the active metal is 30 to 60%.

4. coated catalyst according to one of claims 1 to 3, characterized in that the surface of the active metal is 0.2 to 0.8 m ² / g.

5. coated catalyst according to one of claims 1 to 4, characterized in that it has a Rütteldichte of 400 to 600 g / l.

6. A process for the preparation of a coated catalyst according to any one of claims 1 to 5, comprising the steps:

(A) one or more impregnation of the support material containing silicon dioxide with a solution containing at least one precursor compound of the active metal,

(B) subsequent drying,

(C) subsequent reduction.

7. A process for the hydrogenation of an organic compound containing at least one hydrogenatable group, characterized in that the organic compound is brought into contact with at least one reducing agent and a shell catalyst according to one of claims 1 to 5 in contact.

8. The method according to claim 7, characterized in that the organic compound to be hydrogenated has at least one carbocyclic aromatic group which is hydrogenated to a corresponding carbocyclic aliphatic group, or at least one aldehyde group which is hydrogenated to a corresponding alcohol function.

9. The method according to claim 8, characterized in that the organic compound having at least one carbocyclic aromatic group is selected from the group consisting of benzene, alkyl-substituted benzenes, phenol, alkyl-substituted phenols, aniline, alkyl-substituted aniline, N, N-

Dialkylaniline, diaminobenzene, bis (p-aminophenyl) methane, bis (p-aminotolyl) methane, aromatic carboxylic acids, aromatic carboxylic esters and mixtures thereof.

10. The method according to claim 8, characterized in that the organic compound to be hydrogenated, which has an aldehyde group, is a mono- or disaccharide, which is hydrogenated to the corresponding sugar alcohol.

1 1. Method according to one of claims 7 to 10, characterized in that the hydrogenation takes place in a fixed bed reactor.

12. Use of a coated catalyst according to any one of claims 1 to 5 in a process for the hydrogenation of an organic compound containing at least one hydrogenatable group.

13. Use according to claim 12, characterized in that a carbocyclic aromatic group are hydrogenated to the corresponding carbocyclic aliphatic group or aldehydes to give the corresponding alcohols.