EP1027282A1

EP1027282A1 - Method for hydrogenating an anthraquinone compound

Info

Publication number: EP1027282A1
Application number: EP98959803A
Authority: EP
Inventors: Arnd BÖTTCHER; Jochem Henkelmann; Franz Josef BRÖCKER
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 1997-10-27
Filing date: 1998-10-26
Publication date: 2000-08-16
Also published as: CN1283164A; ID24657A; US6464954B2; AU1557599A; US20020012627A1; MX219608B; WO1999021792A1; MXPA00004065A; KR20010031521A; DE19747407A1; CN1160248C; JP2001521012A; CA2308459A1

Abstract

The invention relates to a method for hydrogenating an anthraquinone compound or a mixture containing two or more anthraquinone compounds using special catalysts, which comprise a metal of the eight subgroup of the periodic table as an active metal.

Description

Process for the hydrogenation of an anthraquinone compound

The present invention relates to a process for the hydrogenation of anthraquinone compounds, in which an anthraquinone compound or a mixture of two or more thereof is brought into contact with a catalyst containing at least one metal of the NHL subgroup of the periodic table as active metal, and also a A process for the production of hydrogen peroxide by the anthraquinone process, which comprises a hydrogenation step as defined above and the reaction of the anthrahydroquinone compound obtained in this step with an oxygen-containing gas.

According to the so-called anthraquinone process, practically all of the hydrogen peroxide produced worldwide is produced.

The process is based on the catalytic hydrogenation of an anthraquinone compound to the corresponding anthrahydroquinone compound, subsequent reaction thereof with oxygen to form hydrogen peroxide and subsequent separation of the hydrogen peroxide formed by extraction. The catalytic cycle is closed by renewed hydrogenation of the re-formed anthraquinone compound.

The diagram below gives an overview of the basic reaction processes:

The anthraquinone compounds used are usually dissolved in a mixture of several organic solvents. The resulting solution is called a working solution. In the anthraquinone process, this working solution is generally carried out continuously through the stages of the process described above.

An overview of the anthraquinone process is given by Ullmann's Encyclopedia of Industrial Chemistry, 5th ed., Vol. A13, pp. 447-456.

A particularly important stage of the anthraquinone process is the hydrogenation stage, in which the anthraquinone compound contained in the working solution is hydrogenated in the presence of a catalyst to give the corresponding anthraquinone compound.

This catalytic hydrogenation can be carried out in suspension or in a fixed bed in different reactor types. The state of the art in this regard is assessed in detail, for example, in EP-A-0 672 617. This document relates to a process of the type in question, using a fixed bed reactor comprising a catalyst bed with an open structure. The catalyst used there is the use of palladium on a support, such as, for example Activated carbon, alumina or silica gel are proposed.

Another variant of the anthraquinone process, also using a fixed bed with a special structure having parallel passages, is described in EP-A-0 102 934. According to this document, as

Active metals for the catalysts described there Precious metals, such as Palladium, platinum, rhodium or mixtures thereof can be used.

An anthraquinone process in suspension mode using a loop reactor and palladium black as a catalyst is described in US 4,428,923.

The use of Pd, Rh, Pt or Ru as active metals in a catalyst, which can also be used for the anthraquinone process, is described in EP-A-0 778 085 and WO 96/18574, where the carrier materials are described catalysts conventional materials such as Al ₂ O ₃ or SiO ₂ are used.

However, the catalysts previously used in the prior art have not always been able to meet the requirements for such catalysts, e.g. high activity with high selectivity at the same time. It was also not always possible to achieve sufficiently high space-time yields.

It is therefore the object of the present invention to provide new processes for the hydrogenation of an anthraquinone compound using catalysts not previously used for this hydrogenation.

Accordingly, in one embodiment, the present invention relates to a process for hydrogenating an anthraquinone compound or a mixture of two or more thereof by contacting the anthraquinone compound or the mixture of two or more thereof with a catalyst to give an anthrahydroquinone compound or a mixture of two or more thereof, wherein the catalyst (catalyst 1) at least one in situ deposited on a support, homogeneous compound of at least one metal of NQ1. Ν Subsidiary group of the periodic table alone or together with at least one metal of I. or VH. Subsidiary group of the periodic table.

Furthermore, the present invention relates to a process for the hydrogenation of an anthraquinone compound, as defined above, wherein the catalyst (catalyst 2) as the active metal is at least one metal of Vm. Ν subgroup of the periodic table alone or together with at least one metal of I. or VE. Ν auxiliary group of the periodic table, applied to a carrier, wherein the carrier has an average pore diameter of at least 50 nm and a surface BET of at most 30 m ² / g and the amount of active metal 0.01 to 30 wt .-%, based on the total weight of the catalyst is, and preferably the ratio of the surfaces of the active metal and the catalyst support is <0.05.

Furthermore, the present invention relates to a process for the hydrogenation of an anthraquinone compound as defined above, the catalyst (catalyst 3) as the active metal being at least one metal of NOT. Ν Subsidiary group of the periodic table alone or together with at least one metal of I. or VH. Ν subgroup of the periodic table in an amount of 0.01 to 30 wt .-%, based on the total weight of the catalyst, applied to a support, wherein 10 to 50% of the pore volume of the support of macropores with a pore diameter in the range of 50 nm up to 10,000 nm and 50 to 90% of the pore volume of the support are formed by mesopores with a pore diameter in the range from 2 to 50 nm, the sum of the pore volumes adding up to 100%.

In a further embodiment, the present invention relates to a Process for the hydrogenation of an anthraquinone compound, as defined above, wherein the catalyst (catalyst 4) as active metal at least one metal of Vm. Sub-group of the periodic table with at least one metal of sub-group I or VII. Sub-group of the periodic table in an amount of 0.01 to 30% by weight, preferably 0.2 to 15% by weight, based on the total weight of the catalyst, applied to a carrier, wherein the carrier has an average pore diameter of at least 0.1 μm, preferably at least 0.5 μm, and a surface area of at most 15 m ² / g, preferably at most 10 m ² / g.

Furthermore, the invention relates to a process for hydrogenating an anthraquinone compound, as defined above, wherein the catalyst (catalyst 5) is a monolithic supported catalyst which is obtained by successively heating in the air and cooling a support material in the form of a metal mesh or a metal foil, followed by coating can be produced in a vacuum with an active component and subsequent cutting and shaping of the coated support material and subsequent processing to form a monolithic supported catalyst, at least one metal of Vm. Subgroup of the periodic table is used alone or together with at least one metal of subgroup I or VII of the periodic table.

In principle, all metals of Viπ can be used as active metal. Subgroup of the periodic table can be used. Platinum, rhodium, palladium, cobalt, nickel or ruthenium or a mixture of two or more thereof are preferably used as active metals, ruthenium in particular being used as the active metal. Among the metals of I. or VE that can also be used. or else the 1st and 7th subgroups of the periodic table, which can also all be used in principle, copper and / or rhenium are preferably used. The terms "macropores" and "micropores" are used in the context of the present invention as they are in Pure Appl. Chem., 45, p. 79 (1976), namely as pores whose diameter is above 50 nm (macropores) or whose diameter is between 2 nm and 50 nm

(Mesopores).

The content of the active metal is generally approximately 0.01 to approximately 30% by weight, preferably approximately 0.01 to approximately 5% by weight and in particular approximately 0.1 to approximately 5% by weight, in each case based on the total weight of the catalyst used, the contents preferably used for catalysts 1 to 5 being again given individually in the discussion of these catalysts.

The term "anthraquinone compound" includes in principle all anthraquinone compounds and the corresponding tetrahydroanthraquinone compounds which can be used for the anthraquinone process for the production of hydrogen peroxide. The compounds which can preferably be used are briefly explained again below in the section "The procedure".

The catalysts 1 to 5 defined above are now to be described in detail below. The description is given by way of example with reference to the use of ruthenium as an active metal. The information below is also applicable to the other active metals that can be used, as defined herein.

CATALYST 1

The process according to the invention can be carried out in the presence of a catalyst 1 which comprises at least one homogeneous compound of at least one metal of Vm deposited on a support in situ. Subgroup of the periodic table, if necessary together with at least one compound of at least one metal of subgroup I or VII. of the periodic table. The catalysts are prepared by introducing a homogeneous metal compound into the reactor during the reaction and depositing it on a support located in the reactor during the reaction.

Furthermore, the homogeneous metal compound can also be introduced into the reactor before the reaction and can be deposited on a support located in the reactor during a treatment with hydrogen.

The term "in situ" used in the context of the present application means that the catalyst is not produced and dried separately and then introduced into the reactor as a finished catalyst, so to speak, but that the catalyst in the context of the present invention is either immediately before or in the reactor is formed during the actual hydrogenation.

The term "homogeneous compound of a metal of VDI., I. or VE. Subgroup of the periodic table" or "homogeneous ruthenium compound" used in the context of the present application means that the metal compound used according to the invention in the medium surrounding it, i.e. the anthraquinone compound that is still to be hydrogenated, or is soluble in a mixture of these compounds with at least one solvent.

The metal compounds used are mainly nitrosyl nitrates and nitrates, but also halides, carbonates, carboxylates, acetylacetonates, chloro-, nitrido- and

Amine complexes and oxide hydrates or mixtures thereof. Preferred compounds are ruthenium nitrosate initiate, Ru & enium (IH) chloride, ruthenium (III) nitrate and ruthenium oxide hydrate.

Although the amount of the metal compound applied to the carrier or carriers in the context of the method according to the invention is not particularly good is limited, from the point of view of sufficient catalytic activity and the economy of the process, the metal salt or the metal complex is applied to the support (s) in such amounts that 0.01 to 30% by weight, based on the total weight of the catalyst , deposits of active metal on the carrier or carriers. This amount is more preferably 0.2 to 15% by weight, particularly preferably about 0.5% by weight.

The supports in the reactor are preferably metal nets and rings and steatite bodies, as are described, inter alia, in EP-A-0 564 830 and EP-A-0 198 435. Nevertheless, the carriers used with particular preference in the context of the present invention and their production are to be briefly explained below.

Metallic support materials, such as stainless steel with material numbers 1.4767, 1.4401, 2.4610, 1.4765, 1.4847, 1.4301 etc., are particularly preferably used, since they can be roughened by tempering their surface before being coated with the active components. Kanthai (material master 1.4767) or metals containing aluminum are particularly preferably used as the net material. Kanthai is an alloy that contains approximately 75% by weight Fe, approximately 20% by weight Cr and approximately 5% by weight Al. For the heat treatment, the above-mentioned metallic supports are heated in air at temperatures of 600 to 1100, preferably 800 to 1000 ° C., for one to twenty, preferably one to ten, hours and then cooled again. This pretreatment is crucial for the activity of the catalyst, since without this tempering treatment practically no ruthenium can be deposited on the metallic support in situ. After this carrier treatment at elevated temperature, they are coated with the ruthenium compound.

In a further preferred embodiment, those described above can Supports are coated with a layer of a palladium metal, such as Ni, Pd, Pt, Rh, preferably Pd, in a thickness of approximately 0.5 to approximately 10 nm, in particular approximately 5 nm, as is also described in the EP mentioned above -A-0 564 830.

As can be seen from the examples according to the invention, in the context of the present invention, in particular a network of tempered Kanthai, onto which a Pd layer was vapor-deposited to facilitate the deposition of the active metal with a thickness of approximately 5 nm, is used as a carrier.

However, customary catalyst support systems, such as, for example, activated carbon, silicon carbide, aluminum oxide, silicon dioxide, titanium dioxide, zirconium dioxide, magnesium oxide, zinc oxide or mixtures thereof, in each case in spherical, stranded or ring form, can also be used. Among these, aluminum oxide and zirconium dioxide are particularly preferred. The pore size and the pore distribution are completely uncritical. Bimodal and all other types of carriers can be used. The supports are preferably macroporous.

Further details regarding catalyst 1 and its production can be found in DE-A 196 22 705.4, the content of which in this regard is fully incorporated into the present application by reference.

CATALYST 2

The catalysts 2 used according to the invention can be prepared industrially by applying at least one metal from subgroup VIII of the periodic table and, if appropriate, at least one metal from subgroup I or VE from the periodic table on a suitable support. The application can be achieved by soaking the carrier in aqueous metal salt solutions, such as, for example, aqueous ruthenium salt solutions, by spraying appropriate metal salt solutions onto the carrier or by other suitable processes. As metal salts of I., VE. or VTII. Subgroup of the periodic table are the nitrates, nitrosyl nitrates, halides, carbonates, carboxylates, acetylacetonates, chloro complexes, nitrite complexes or amine complexes of the corresponding metals, with the nitrates and nitrosyl nitrates being preferred.

In the case of catalysts which, in addition to the metal of VHI. Subgroup of the periodic table also contain other metals applied as active metal on the support, the metal salts or metal salt solutions can be applied simultaneously or in succession.

The supports coated or impregnated with the metal salt solution are then dried, preferably at temperatures between 100 ° C. and 150 ° C., and optionally caicinated at temperatures between 200 ° C. and 600 ° C., preferably between 350 ° C. and 450 ° C. If the impregnation is carried out separately, the catalyst is dried after each impregnation step and optionally caicinated, as described above. The order in which the active components are soaked is freely selectable.

The coated, dried and optionally calcined carriers are then activated by treatment in a gas stream containing free hydrogen at temperatures between approximately 30 ° C. and approximately 600 ° C., preferably between approximately 150 ° C. and approximately 450 ° C. The gas stream preferably consists of 50 to 100% by volume of H ₂ and 0 to 50% by volume of N ₂ .

The metal salt solution or solutions are applied to the carrier or carriers in such an amount that the total content of active metal, in each case based on the total weight of the catalyst, about 0.01 to about 30% by weight, preferably about 0.01 to about 5% by weight, more preferably about 0.01 to about 1% by weight, and especially about 0.05 is up to about 1% by weight.

The total metal surface area on the catalyst is preferably approximately 0.01 to approximately 10 m ² / g, more preferably approximately 0.05 to approximately 5 m ² / g and in particular approximately 0.05 to approximately 3 m ² / g of the catalyst. The metal surface is by means of the by J. LeMaitre et al. in "Characterization of Heterogenous Catalysts", ed. Francis Delanney, Marcel Dekker, New York 1984, pp. 310-324.

In the catalyst used according to the invention, the ratio of the surfaces of the active metal (s) and the catalyst carrier is preferably less than about 0.05, the lower limit being about 0.0005.

The support materials which can be used to prepare the catalysts used according to the invention are those which are macroporous 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 their surface area according to BET at most about 30 m ² / g , preferably at most about 15 m ² / g, more preferably at most about 10 m ² / g, in particular at most about 5 m ² / g and more preferably at most about 3 m ² / g. More specifically, the mean pore diameter of the carrier is preferably about 100 nm to about 200 μm, more preferably about 500 nm to about 50 μm. The surface area of the carrier is preferably approximately 0.2 to approximately 15 m ² / g, more preferably approximately 0.5 to approximately 10 m ² / g, in particular approximately 0.5 to approximately 5 m ² / g and further preferably approximately 0, 5 to about 3 m ² / g. The surface of the support is determined by the BET method by N ₂ adsorption, in particular in accordance with DIN 66131. The average pore diameter and the pore size distribution are determined by mercury porosimetry, in particular in accordance with DIN 66133.

The pore size distribution of the carrier can preferably be approximately bimodal, the pore diameter distribution with maxima at approximately 600 nm and approximately 20 μm in the bimodal distribution being a special embodiment of the invention.

A carrier with a surface area of 1.75 m ² / g is further preferred which has this bimodal distribution of the pore diameter. The pore volume of this preferred carrier is preferably about 0.53 ml / g.

For example, activated carbon, silicon carbide, aluminum oxide, silicon dioxide, titanium dioxide, zirconium dioxide, magnesium oxide, zinc oxide or mixtures of two or more thereof can be used as the macroporous carrier material, aluminum oxide and zirconium dioxide being preferably used.

Further details regarding catalyst 2 and its production can be found in DE-A 196 24 484.6, the content of which in this regard is fully incorporated into the present application by reference.

CATALYST 3

The catalysts 3 used according to the invention can be produced industrially by applying an active metal of Vm. Subgroup of the

Periodic table, preferably ruthenium or palladium and optionally at least one metal of I. or VTI. Subsidiary of the periodic table a suitable carrier. The application can be achieved by soaking the support in aqueous metal salt solutions, such as ruthenium or palladium salt solutions, by spraying appropriate metal salt solutions onto the support or by other suitable methods. Suitable metal salts for the preparation of the metal salt solutions are the nitrates, nitrosyl nitrates, halides, carbonates, carboxylates, acetylacetonates, chlorine complexes, nitrite complexes or amine complexes of the corresponding metals, with the nitrates and nitrosyl nitrates being preferred.

In the case of catalysts which contain several active metals applied to the support, the metal salts or metal salt solutions can be applied simultaneously or in succession.

The supports coated or soaked with the metal salt solution are then dried, temperatures between 100 ° C. and 150 ° C. being preferred. These carriers can optionally be caicinated at temperatures between 200 ° C. and 600 ° C., preferably 350 ° C. to 450 ° C. The coated supports are then activated by treatment in a gas stream which contains free hydrogen at temperatures between 30 ° C. and 600 ° C., preferably between 100 ° C. and 450 ° C. and in particular between 100 ° C. and 300 ° C. The gas stream preferably consists of 50 to 100% by volume of H ₂ and 0 to 50% by volume of N ₂ .

If several active metals are applied to the carrier and the application is carried out in succession, the carrier can be dried at temperatures between 100 ° C and 150 ° C after each application or soaking and optionally caicinated at temperatures between 200 ° C and 600 ° C. The order in which the metal salt solution is applied or soaked can be chosen arbitrarily. The metal salt solution is applied to the carrier (s) in such an amount that the active metal content is 0.01 to 30% by weight, preferably 0.01 to 10% by weight, more preferably 0.01 to 5% by weight. % and in particular 0.3 to 1 wt .-%, based on the total weight of the catalyst.

The total metal surface area on the catalyst is preferably 0.01 to 10 m ² / g, more preferably 0.05 to 5 m ² / g and further preferably 0.05 to 3 m ² / g of the catalyst. The metal surface was measured by the chemisorption method as described in J. LeMaitre et al., "Characterization of Heterogeneous Catalysts", ed. Francis Delanney, Marcel Dekker, New York (1984), pp. 310-324.

In the catalyst used according to the invention, the ratio of the surfaces of the at least one active metal and the catalyst support is less than about 0.3, preferably less than about 0.1 and in particular about 0.05 or less, the lower limit being about 0.0005.

The support materials which can be used to produce the catalysts used according to the invention have macropores and mesopores.

The carriers which can be used according to the invention have a pore distribution which corresponds to approximately 5 to approximately 50%, preferably approximately 10 to approximately 45%, further preferably approximately 10 to approximately 30% and in particular approximately 15 to approximately 25% of the pore volume of macropores having a pore diameter in Range from about 50 nm to about 10,000 nm and from about 50 to about 95%, preferably from about 55 to about 90%, more preferably from about 70 to about 90% and especially from about 75 to about 85% of the pore volume of mesopores with a pore diameter knives from approximately 2 to approximately 50 nm are formed, the sum of the pore volumes adding up to 100% in each case. The total pore volume of the supports used according to the invention is approximately 0.05 to 1.5 cm ³ / g, preferably approximately 0.1 to 1.2 cm ³ / g and in particular approximately 0.3 to 1.0 cm ³ / g. The average pore diameter of the supports used according to the invention is approximately 5 to 20 nm, preferably approximately 8 to 15 nm and in particular approximately 9 to 12 nm.

Preferably, the surface of the support is about 50 to about 500 m ² / g, more preferably about 200 to about 350 m ² / g, and most preferably about 200 to about 250 m ² / g of the support.

The surface of the support is determined by the BET method by N ₂ adsorption, in particular according to DIN 66131. The average pore diameter and the size distribution are determined by mercury porosimetry, in particular according to DIN 66133.

Although in principle all of the support materials known in catalyst production, i.e. which have the pore size distribution defined above, 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, are preferably used.

Further details regarding catalyst 3 and its production can be found in DE-A 196 24 485.4, the content of which in this regard is fully incorporated into the present application by reference.

CATALYST 4

The catalysts 4 used according to the invention can be manufactured industrially are applied by applying an active metal of Vm. Subgroup of the periodic table and optionally at least one metal of I. or VE. Subgroup of the periodic table on a suitable support. The application can be achieved by soaking the support in aqueous metal salt solutions, such as ruthenium salt solutions, by spraying appropriate metal salt solutions onto the support or by other suitable methods. As ruthenium salts for the preparation of the ruthenium salt solutions as well as metal salts of I., VE. or VEI. Subgroups are the nitrates, nitrosyl nitrates, halides, carbonates, carboxylates, acetylacetonates, chlorine complexes, nitrite complexes or amine complexes of the corresponding metals, preference being given to the nitrates and nitrosyl nitrates.

In the case of catalysts which contain several metals applied to the support, the metal salts or metal salt solutions can be applied simultaneously or in succession.

The supports coated or impregnated with the ruthenium salt or metal salt solution are then dried, preferably at temperatures between 100 ° C. and 150 ° C., and optionally caicinated at temperatures between 200 ° C. and 600 ° C.

Subsequently, the coated supports are activated by treating the coated supports in a gas stream containing free hydrogen

Temperatures between 30 and 600 ° C, preferably between 150 and 450 ° C. The gas stream preferably consists of 50 to 100% by volume of H ₂ and 0 to 50% by volume

N ₂ .

Are on the carrier in addition to the active metal of subgroup VIII

Periodic table metals of I. or VH. Applied and if the application is carried out one after the other, the wearer can after each application or Potions can be dried at temperatures between 100 and 150 ° C and caicinated optionally at temperatures between 200 and 600 ° C. The order in which the metal salt solutions are applied or soaked can be chosen as desired.

The metal salt solution is applied to the carrier (s) in such an amount that 0.01 to 30% by weight, based on the total weight of the catalyst, of active metal is present on the carrier. This amount is preferably 0.2 to 15% by weight, particularly preferably about 0.5% by weight.

The total metal surface area on the catalyst is preferably 0.01 to 10 m ² / g, particularly preferably 0.05 to 5 m ² / g, in particular 0.05 to 3 m ² per g of the catalyst.

The support materials which can be used to produce the catalysts used according to the invention are preferably those which are macroporous and have an average pore diameter of at least 0.1 μm, preferably at least 0.5 μm and a surface area of at most 15 m ² / g, preferably at most 10 m ² / g, particularly preferably at most 5 m ² / g, in particular at most 3 m ² / g. The mean pore diameter of the carrier is preferably in a range from 0.1 to 200 μm, in particular 0.5 to 50 μm. The surface of the support is preferably 0.2 to 15 m ² / g, particularly preferably 0.5 to 10 m ² / g, in particular 0.5 to 5 m ² / g, especially 0.5 to 3 m ² per g of the Carrier.

The surface of the support is determined by the BET method by N ₂ adsorption, in particular in accordance with DIN 66131. The average pore diameter and the pore size distribution were determined by mercury porosimetry, in particular in accordance with DIN 66133. The pore size distribution of the Carrier be approximately bimodal, the pore diameter Distribution with maxima at approximately 0.6 μm and approximately 20 μm in the bimodal distribution represents a special embodiment of the invention.

A carrier with a surface area of approximately 1.75 m ² / g is particularly preferred which has this bimodal distribution of the pore diameter. The pore volume of this preferred carrier is preferably about 0.53 ml / g.

For example, activated carbon, silicon carbide, aluminum oxide, silicon dioxide, titanium dioxide, zirconium dioxide, magnesium oxide, zinc oxide or mixtures thereof can be used as the macroporous carrier material. Aluminum oxide and zirconium dioxide are preferred.

Further details regarding catalyst 4 and its production can be found in DE-A 196 04 791.9, the content of which in this regard is fully incorporated into the present application by reference.

CATALYST 5

The catalyst 5 used in accordance with the invention can be produced by successively heating the carrier material in the form of a metal mesh or a metal foil in the air, cooling it and coating it in vacuo with the active metal described above or the combination of two or more thereof, and then the coated carrier material cut, deformed and ultimately processed into a monolithic catalyst element. This catalyst and its preparation have already been described in detail in EP-A-0 564 830 and US Pat. No. 4,686,202, the content of which in this regard is included in full in the context of the present application. In the following, the essential principles of the production of this catalyst or the preferred embodiments are to be repeated the same are briefly discussed, with regard to the active metals used the same applies to the catalysts 1 to 4.

Stainless steels, such as those with the material numbers 1.4767, 1.4401, 2.4610, 1.4765, 1.4847, 1.4301 etc., are particularly suitable as metallic carrier materials in the form of metal foils or metal meshes, because they get a roughening of their surface by tempering before coating with active components can. For this purpose, the metallic supports are heated in air at temperatures of 600 to 1100 ° C., preferably 800 to 1000 ° C. for 1 to 20, preferably 1 to 10 hours, and cooled again. This pretreatment is crucial for the activity of the catalyst. After this carrier treatment at elevated temperature, the active component is coated. For this purpose, the support is coated in vacuo at a pressure of 10 ^"3 to 10 ^{" 5} mbar by means of an evaporation device, for example electron beam evaporation or sputtering device, with the active component at the same time or in succession in a batch or continuous procedure. Tempering under inert gas or air can be followed to form the catalyst.

The production of catalyst layers described here is about producing disordered and disturbed polycrystalline layers or clusters. Therefore, particularly good vacuum conditions are not normally required. Furthermore, by alternately evaporating active components and structural promoters, the active components can be produced in a very fine crystalline or cluster form.

You can systematically build the catalyst here, for example in one

Steaming system with several different evaporation sources. For example, an oxide layer or an adhesive layer can be applied to the support by reactive evaporation. On this grand layer you can Manufacture active components and promoters in several alternating layers. By introducing a reactive gas into the recipient, promoter layers can be produced from oxides or other compounds. Annealing processes can also be interposed.

As a result of this type of production of the catalyst fabric or the catalyst foils, the active components have such good adhesive strength that they can now be cut, deformed and processed into monolithic catalyst elements.

A very simple monolithic catalyst is obtained if the catalyst fabric or the catalyst foil is deformed by means of a gear roller and smooth and corrugated fabric or foil is rolled up to form a cylindrical monolith with similar vertical channels. However, any static mixer can also be formed from this catalyst material, since the adhesive strength of the catalyst layer is sufficiently high.

The monolithic catalyst elements produced in the form of mixing elements are installed in a reactor and a reaction liquid to be reacted is applied.

THE PROCEDURE

In the process according to the invention, the hydrogenation stage is generally carried out at a temperature of approximately 20 to 120 ° C., preferably approximately 30 to 80 ° C. The pressures used are generally about 1 to about 20 bar, preferably about 2 to 10 bar.

Either pure hydrogen or a hydrogen can be used for hydrogenation containing gas can be used.

The hydrogenation is generally carried out up to a conversion of approximately 50 to 70% in order to achieve the highest possible selectivity of generally> 90%, preferably> 95%.

According to the invention, 2-alkylanthraquinones, such as e.g. 2-ethyl, 2-tert-butyl, 2-amyl, 2-methyl, 2-butyl, 2-isopropyl, 2-sec-butyl, 2-sec-amylanthraquinone, and polyalkylanthraquinones, such as 1,3-diethylanthraquinone, 2,3-dimethylanthraquinone, 1,4-dimethylanthraquinone, 2,7-dimethylanthraquinone, and the corresponding tetrahydroanthraquinone compounds, and mixtures of two or more thereof.

All solvents known from the prior art for anthraquinone or anthrahydroquinone compounds can be used as solvents. Mixtures of two or more solvent components are preferred, since such solvent mixtures best take into account the different solution properties of the anthraquinone and anthrahydroquinone compound. Examples include: Mixtures of methyl naphthalene and nonyl alcohol, methyl naphthalene and tetrabutyl urea, polyalkylated benzene and alkyl phosphates or methyl naphthalene, tetrabutyl urea and alkyl phosphates.

With regard to the reactors which can be used in the process according to the invention, there are likewise no restrictions, so that all reactors known from the prior art and suitable for hydrogenation can be used.

In addition, the present invention also relates to a method for producing hydrogen peroxide by the anthraquinone method, which the following stages (1) and (2):

(1) hydrogenating an anthraquinone compound or a mixture of two or more thereof by a method as defined above, whereby an anthrahydroquinone compound or a mixture of two or more thereof is obtained; and

(2) reacting the anthrahydroquinone compound or the mixture of two or more thereof with an oxygen-containing gas to obtain a mixture containing hydrogen peroxide and the anthraquinone compound or the mixture of two or more thereof.

Steps (1) and (2) are preferably carried out continuously, more preferably continuously with recycling of the anthraquinone compound obtained in step (2) carried out in step (1), the recycling of the anthraquinone compound as part of a working solution removal of the hydrogen peroxide formed.

The extraction of the hydrogen peroxide is carried out in a further stage (3) in a further embodiment of the process according to the invention by means of an extractant containing water, the use of pure water being preferred here.

Regarding the general rules for performing the anthraquinone procedure, i.e. of the procedure that the above Levels (1) to (3) includes, reference is made to the prior art mentioned above.

The present invention will now be explained in more detail using examples according to the invention. EXAMPLES

example 1

In a 3.5 liter autoclave, a mesh with a 1 mm mesh diameter made of tempered Kanthai, onto which a Pd layer with a thickness of 5 nm had been evaporated, was attached. A comparison test showed that this Pd-coated network was not catalytically active. In the first drive was added a 13% strength solution of 2-ethylanthraquinone in a mixture of Shellsol ^® and Tetrabutylhamstoff (70:30) together with 200 mg of ruthenium nitrosyl nitrate in the autoclave 2. 1

The mixture was then 60 min. hydrogenated at 10 bar hydrogen pressure and 60 ° C. The reaction discharge was free from ruthenium. 2-ethylanthraquinone was converted with 100% selectivity to 2-ethylanthraquinroquinone (conversion: 72%). On the second trip, 2 l of this solution were reacted with hydrogen on the network catalyst without adding ruthenium.

The reaction discharge was free from traces of ruthenium. 75% of 2-ethylanthraquinone was converted (selectivity: 100%).

Example 2

A stainless steel mesh (material no. 1.4767) was heated in the air in a muffle furnace at 900 ° C for 5 h. The tissue thus obtained was deformed with a gear roller and then the corrugated piece of fabric rolled up with a smooth piece of fabric. The monolith thus obtained was installed with a precise fit in a continuous 0.3 l hydrogenation reactor. 2 g of ruthenium nitrosyl nitrate were dissolved in 500 ml of a mixture of Shell sol ^® / tetrabutyl urea (70:30). This solution was continuously fed into the reactor at a hydrogen pressure of 10 bar and 100 ° C. in an amount of 60 ml / h. The reaction product obtained was colorless and free of ruthenium. After all the ruthenium-containing solution, the working solution (13% of 2-ethylanthraquinone in Shellsol ^® / tetrabutyl urea (70:30) continuously at 40 ° C and 10 bar hydrogen pressure without the addition of ruthenium in an amount of 300 ml / h further in driven the reactor.

The gas chromatographic evaluation showed a conversion of 62% and a selectivity of 100% with respect to the 2-ethylanthrahydroquinone.

Claims

claims

1. A method of hydrogenating an anthraquinone compound or a mixture of two or more thereof by contacting the anthraquinone compound or the mixture of two or more thereof with a catalyst, thereby obtaining an anthraquinroquinone compound or a mixture of two or more thereof , characterized in that the catalyst comprises at least one homogeneous compound deposited in situ on a support of at least one metal of the VUL subgroup alone or together with at least one metal of I. or VTI. Subsidiary of the periodic table.

2. A method of hydrogenating an anthraquinone compound or a mixture of two or more thereof by contacting the anthraquinone compound or the mixture of two or more thereof with a catalyst to obtain an anthraquinroquinone compound or a mixture of two or more thereof , characterized in that the catalyst as an active metal at least one metal of Vm. Secondary group of the periodic table, alone or together with at least one metal of the first or seventh second group of the periodic table, applied to a carrier, wherein the carrier has an average pore diameter of at least 50 nm and a BET surface area of at most 30 m ² / g and the amount of active metal is 0.01 to 30% by weight, based on the total weight of the catalyst.

3. A method of hydrogenating an anthraquinone compound or a mixture of two or more thereof by contacting the anthraquinone compound or the mixture of two or more thereof with a catalyst, thereby obtaining an anthraquinroquinone compound or a mixture of two or more thereof , characterized in that the Catalyst as active metal at least one metal of Vm. Subgroup of the periodic table alone or together with at least one metal of subgroup I or VII. Group 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 carrier of macropores with a pore diameter in the range from 50 nm to 10,000 nm and 50 to 90% of the pore volume of the carrier of mesopores with a pore diameter in the range of 2 to 50 nm are formed, the sum of the pore volumes increasing 100% added.

4. A method of hydrogenating an anthraquinone compound or a mixture of two or more thereof by contacting the anthraquinone compound or the mixture of two or more thereof with a catalyst to obtain an anthraquinroquinone compound or a mixture of two or more thereof , characterized in that the

Catalyst as active metal at least one metal of Vm. Subsidiary group of the periodic table alone or together with at least one metal of I. or VE. Subgroup of the periodic table in an amount of 0.01 to 30 wt .-%, based on the total weight of the catalyst, applied to a carrier, wherein the carrier has an average pore diameter of at least 0.1 microns, and a surface BET of at most 15 m ² / g.

5. A method of hydrogenating an anthraquinone compound or a mixture of two or more thereof by contacting the anthraquinone compound or the mixture of two or more thereof with a catalyst to obtain an anthraquinroquinone compound or a mixture of two or more thereof , characterized in that the catalyst is a monolithic supported catalyst which is obtained by successively heating and cooling in air Support material in the form of a metal mesh or a metal foil, subsequent coating in vacuo with an active component and subsequent cutting and shaping of the coated support material and final processing into a monolithic supported catalyst, with at least one metal being the active metal

Viπ. Subgroup of the periodic table alone or together with at least one metal of I. or VE. Subgroup of the periodic table is used.

6. A process for the production of hydrogen peroxide by the anthraquinone process, which comprises the following steps (1) and (2):

(1) hydrogenation of an anthraquinone compound or a mixture of two or more thereof by a method according to any one of claims 1 to 5, whereby an anthrahydroquinone compound or a mixture of two or more thereof is obtained; and

7. The method according to claim 6, wherein steps (1) and (2) are carried out continuously.

8. The method according to claim 6 or 7, which additionally comprises the following step (3):

(3) extraction of the hydrogen peroxide from the mixture, the hydrogen peroxide and the anthraquinone compound or the

Mixture of two or more of them contains by means of water containing extractant.

9. The method according to any one of claims 1 to 8, wherein a 2-alkylanthraquinone or a mixture of two or more thereof is used as the anthraquinone compound.