WO2024037905A1

WO2024037905A1 - Method for producing bulk catalyst shaped bodies for gas-phase oxidation of an alkene and/or an alcohol to form an a,b-unsaturated aldehyde and/or an a,b-unsaturated carboxylic acid

Info

Publication number: WO2024037905A1
Application number: PCT/EP2023/071775
Authority: WO
Inventors: Kazuhiko Amakawa; Josef Macht; Christian Walsdorff; Markus Muehl; Cathrin Alexandra Welker-Nieuwoudt; William Owen TUTTLE; Thorsten Johann; Samira PARISHAN; David SCHLERETH
Original assignee: Basf Se
Priority date: 2022-08-16
Filing date: 2023-08-07
Publication date: 2024-02-22

Abstract

The present invention relates to a method for producing bulk catalyst shaped bodies for gas-phase oxidation of an alkene and/or an alcohol to form an α,β-unsaturated aldehyde and/or an α,β-unsaturated carboxylic acid, wherein a precursor shaped body with a density of from 1.20 to 1.70 g/cm³ is produced by compression, the precursor shaped body is thermally treated and the weight loss during the thermal treatment is from 25 to 45 wt.%.

Description

Process for the production of unsupported shaped catalyst bodies for the gas phase oxidation of an aiken and/or an alcohol to form an α,β-unsaturated aldehyde and/or an α,β-unsaturated carboxylic acid

The present invention relates to a process for producing unsupported catalyst moldings for the gas phase oxidation of an Aiken and/or an alcohol to form an α,β-unsaturated aldehyde and/or an α,β-unsaturated carboxylic acid, whereby compression produces a precursor molding with a density of 1.20 up to 1.70 g/cm ³ is produced, the precursor shaped body is thermally treated and the weight loss during the thermal treatment is 25 to 45% by weight.

The present invention also relates to the shaped solid catalyst bodies obtainable according to the invention and their use for heterogeneously catalyzed partial gas phase oxidation on a fixed catalyst bed.

US 2005/0065371 describes shaped catalyst bodies containing at least the elements molybdenum, bismuth and iron, for gas phase oxidation.

US 2006/0036111 discloses a gas phase oxidation process for producing an α,β-unsaturated aldehyde and/or an α,β-unsaturated carboxylic acid. The ignition loss during calcination must be within a defined range.

WO 2010/000720 teaches a process for producing shaped solid catalyst bodies.

WO 2013/007736 discloses shaped catalyst bodies containing at least the elements molybdenum, bismuth, iron and cobalt, for gas phase oxidation. The elements bismuth, iron and cobalt must be present in a defined ratio.

WO 2015/067659 describes hollow cylindrical shaped catalyst bodies with a defined geometry. The solid catalyst moldings have a high stability and a high selectivity of valuable products in the gas phase oxidation of propene to acrolein and acrylic acid.

WO 2021/239483 discloses shaped solid catalyst bodies with a defined cylindrical structure. The solid catalyst moldings enable high packing density and a low pressure loss in the fixed catalyst bed.

None of the above-mentioned patent applications attaches any importance to the pressure used in the production of the precursor moldings or the density of the precursor molding.

The object of the present invention was to provide an improved process for producing unsupported catalysts for the gas phase oxidation of an Aikens and/or an alcohol to an α,β-unsaturated aldehyde and/or an α,β-unsaturated carboxylic acid. The catalysts should show improved selectivity of valuable products and an improved yield of valuable products. The value product is the sum of acrolein and acrylic acid.

The object according to the invention is achieved by a process for producing unsupported shaped catalyst bodies for the gas phase oxidation of an aikene and/or an alcohol to form an α,ß-unsaturated aldehyde and/or an α,ß-unsaturated carboxylic acid, the unsupported shaped catalyst bodies containing at least the elements molybdenum, bismuth, Iron, cobalt and optionally nickel, wherein a) an aqueous solution or aqueous suspension is produced from at least one source of the elemental constituents molybdenum, bismuth, iron, cobalt and optionally at least one source of the elemental constituent nickel, b) by drying the aqueous solution or aqueous suspension obtained in a) and optionally comminution, a powder P is produced, c) that powder P obtained in b), optionally with the addition of one or more auxiliaries and after uniform mixing and optional compaction, is compacted into precursor moldings with a cylindrical structure, and d) those obtained in c). Precursor moldings are thermally treated to form the solid catalyst moldings, characterized in that the pressure during compression in c) is selected so that the density of the precursor moldings is from 1.70 to 2.30 g / cm ³ , the density of the precursor moldings being The quotient of the mass and the geometric volume is, and the weight loss during the thermal treatment in d) is from 25 to 40% by weight.

The geometric volume is the macroscopic volume of the precursor molding including the pores. For the sake of completeness, it is emphasized that the continuous, essentially circular holes as well as any surface structures such as grooves, notches or serrations are not part of the macroscopic volume.

A cylindrical structure is a cylindrical body, preferably with at least one circular opening continuous in the longitudinal direction. In the case of a continuous opening, this is arranged in the middle (hollow cylinder). In the case of multiple continuous openings, these are evenly distributed across the cross section of the cylindrical structure. A cylindrical structure with three through openings is described, for example, in WO 2021/239483.

The thermal treatment includes an optional thermal pretreatment and the actual calcination.

The pressure during compression in c) is selected so that the density of the precursor moldings is preferably from 1.72 to 2.28 g/cm ³ , preferably from 1.74 to 2.26 g/cm ³ , particularly preferably from 1. 76 to 2.24 g/cm ³ , very particularly preferably from 1.78 to 2.22 g/cm ³ , most preferably from 1.80 to 2.20 g/cm ³ .

The weight loss during the thermal treatment in d) is preferably from 26 to 39% by weight, preferably from 27 to 38% by weight, particularly preferably from 28 to 37% by weight, very particularly preferably from 29 to 36% by weight. -%, most preferably from 30 to 35% by weight.

The weight loss during the thermal treatment can be adjusted, for example, by using substances that decompose during the thermal treatment.

Suitable cylindrical structures are cylindrical bodies with a circular through-hole in the center in the longitudinal direction (hollow cylinder) and cylindrical bodies with three notches evenly in the longitudinal direction and three circular through-holes arranged evenly in the longitudinal direction. The latter cylindrical structures are described in WO 2021/239483.

The shortest distance between the outer wall of the cylindrical body and the next through opening is preferably from 0.75 to 2.5 mm, preferably from 0.8 to 2.0 mm, particularly preferably from 1.0 to 1.8 mm, in total particularly preferably from 1.2 to 1.7 mm, most preferably from 1.3 to 1.6 mm. In the case of a hollow cylinder, the shortest distance between the outer wall of the cylindrical body and the next through opening corresponds to the wall thickness of the hollow cylinder.

The molybdenum content of the unsupported catalyst moldings, calculated as MoOs, preferably from 45 to 75% by weight, particularly preferably from 50 to 70% by weight, very particularly preferably from 55 to 65% by weight.

The bismuth content of the unsupported catalyst moldings, calculated as Bi2Ö3, is from 1 to 20% by weight, particularly preferably from 2 to 15% by weight, very particularly preferably from 3 to 10% by weight.

The iron content of the unsupported catalyst moldings, calculated as Fe2Ö3, is from 2 to 12% by weight, particularly preferably from 3 to 11% by weight, very particularly preferably from 4 to 10% by weight.

The content of cobalt and nickel in the solid catalyst moldings, calculated as CoO and NiO, is in total from 9 to 30% by weight, particularly preferably from 12 to 27% by weight, very particularly preferably from 15 to 24% by weight.

The solid catalyst moldings can additionally contain the elements potassium and/or silicon.

A further subject of the present invention is the solid catalyst moldings produced according to the process according to the invention with a cylindrical structure for the gas phase oxidation of an Aikens and/or an alcohol to an α,β-unsaturated aldehyde and/or an α,β-unsaturated carboxylic acid, wherein the solid catalyst molding at least which comprises the elements molybdenum, bismuth, iron and cobalt, characterized in that the density of the solid catalyst shaped body is from 1.20 to 1.70 g/cm ³ , the density of the solid catalyst shaped body being the quotient of the mass and the geometric volume, which Total pore volume of the unsupported shaped catalyst body is from 0.33 to 0.60 cm ³ /g and the pore volume of the unsupported shaped catalyst body is in the range of 0.1 to 1 pm from 85 to 99% of the total pore volume, the total pore volume and the pore volume being in the range of 0. 1 to 1 pm is determined by mercury porosimetry.

The geometric volume is the macroscopic volume of the solid catalyst molding including the pores. For the sake of completeness, it is emphasized that the continuous, essentially circular holes as well as any surface structures such as grooves, notches or serrations are not part of the macroscopic volume.

The density of the unsupported catalyst shaped body is preferably from 1.22 to 1.68 g/cm ³ , preferably from 1.24 to 1.66 g/cm ³ , particularly preferably from 1.26 to 1.64 g/cm ³ , very particularly preferably from 1.28 to 1.62 g/cm ³ , most preferably from 1.30 to 1.60 g/cm ³ ,

The total pore volume of the unsupported shaped catalyst body is preferably from 0.34 to 0.58 cm ³ /g, preferably from 0.35 to 0.56 cm ³ /g, particularly preferably from 0.36 to 0.54 cm ³ /g, very particularly preferably from 0.37 to 0.52 cm ³ /g, most preferably from 0.38 to 0.50 cm ³ /g,

The pore volume of the unsupported shaped catalyst body in the range from 0.1 to 1 μm is preferably from 86 to 98%, preferably from 87 to 97%, particularly preferably from 88 to 96%, very particularly preferably from 89 to 95% of the total pore volume.

Preferred unsupported shaped catalyst bodies are multi-element oxides of the general formula I

Moi ₂ BiaFebCOcNidXeYfZgO _n (I) with

X = K, Cs and/or Rb

Y = Ca, Sr, Ba, Li, Na, Cr, W, Mn, Cu, Zn, Ga, P, B, As, Sn, Sb, Te, Nb, Ta, Pb, Ce and/or La Z = Si , Al, Ti, Zr and/or Mg a = 0.2 to 2 b = 1 to 4 c = 3 to 9 d = 0 to 4 c + d = 4 to 9.5 e = 0.01 to 0.5 f = 0 to 10 g = 0 to 10 n = a number determined by the valence and frequency of the elements other than oxygen in general formula I.

Further objects of the present invention are processes for producing an α,β-unsaturated aldehyde and/or an α,β-unsaturated carboxylic acid, wherein an alkene and/or an alcohol, in particular propene, is reacted with molecular oxygen over a fixed catalyst bed comprising a bed comprises unsupported shaped catalyst bodies according to the invention, is passed and fixed bed reactors containing a bed of unsupported shaped catalyst bodies according to the invention.

The present invention is based on the knowledge that the pressure used in the production of the precursor moldings and the weight loss that occurs during the thermal treatment have a significant influence on the selectivity of the valuable product and the yield of the valuable product.

The production of the solid catalyst moldings is described below:

The solid catalyst moldings obtainable according to the invention are usually formed in bulk into geometric moldings, calcined and used to catalyze the respective heterogeneously catalyzed gas phase partial oxidation (in particular that of propene to acrolein). In principle, the desired geometry of the solid catalytic converters is not subject to any restrictions.

In principle, shaped solid catalyst bodies can be produced in a simple manner by using suitable sources of their elemental constituents (in particular those other than oxygen) to produce a dry mixture that is as intimate as possible, preferably finely divided, and has a composition corresponding to the respective stoichiometry of the shaped solid catalyst bodies to be produced, and this after previous shaping into precursor shaped bodies , which optionally takes place with the use of shaping aids, calcined at temperatures of 350 to 650 ° C. The calcination can be carried out both under an inert gas and under an oxidative atmosphere such as air (or another mixture of inert gas and molecular oxygen, which can also contain reducing components in comparatively smaller proportions) as well as under a reducing atmosphere (for example a mixture of Inert gas, NH ₃ , CO and/or H ₂ , which can also contain oxidizing components in comparatively smaller proportions) or under vacuum. The calcination time can be from a few minutes to a few days and is usually shorter at elevated calcination temperatures.

Sources for the elemental constituents of the unsupported shaped catalyst bodies (that is, as starting compounds which contain chemically bound at least one elemental constituent (at least one element contained in the unsupported shaped catalyst body)) come from these Compounds into consideration which are already oxides (which are generally in the solid state under normal conditions (1 atm, 0 ° C)) (for example metal oxides) and/or those compounds which can be formed by heating (thermal treatment). elevated temperature), at least in the presence of gaseous oxygen and / or gaseous (for example molecular) oxygen-releasing components, can be converted into oxides (usually in the solid state under normal conditions). In principle, the oxygen source can be part of the mixture to be calcined, for example in the form of a peroxide. In general, a starting compound can be a source for several elementary constituents of the unsupported shaped catalyst bodies.

In addition to the oxides, suitable starting compounds (sources) include halides, nitrates, formates, acetates, oxalates, citrates, carbonates, ammine complexes, ammonium salts and/or hydroxides and hydrates of the aforementioned salts.

Compounds such as NH ₄ OH, (NH ₄ ) ₂ CO3, NH ₄ NO ₃ , NH ₄ CHO ₂ , CH3COOH, NH ₄ CH ₃ CO ₂ and/or ammonium oxalate, which, at the latest during subsequent calcination, essentially completely form gaseous compounds (for example Ammonia, CO ₂ , CO, H2O, nitrogen oxides) decompose and/or decompose can also be incorporated into the intimate dry mixture. Organic materials such as stearic acid, malonic acid, ammonium salts of the aforementioned acids, starches (e.g. potato starch, corn starch), ground nut shells and finely divided plastic flour (e.g. polyethylene, polypropylene, etc.) can also be considered as substances that decompose during calcination.

A formation (release) of gaseous compounds in the context of the thermal treatment outlined normally occurs even if the element sources with which the most intimate and preferably finely divided dry mixture is produced are partly organic in nature (for example in the case of acetates, formates, Oxalates and/or citrates) or hydroxide ions, carbonate ions, hydrogen carbonate ions, ammonium ions, halide ions, hydrogen phosphate ions and/or nitrate ions, which normally decompose during calcination.

The intimate mixing of the starting compounds (sources) to produce shaped unsupported catalyst bodies can be carried out in dry or wet form. If it is done in dry form, the starting compounds (the sources) are expediently used as finely divided powders and are subjected to calcination after mixing and compacting to form the geometric precursor shaped body.

According to the invention, however, the intimate mixing of the (elemental) sources preferably takes place in wet form.

The starting compounds are mixed together in the form of solutions and/or suspensions and the resulting wet (preferably aqueous) mixture M is then dried to form an intimate dry mixture. Water or an aqueous solution is preferably used as the solvent and/or suspending agent, with an aqueous mixture M resulting as the wet mixture M.

Particularly intimate dry mixtures are obtained in the mixing process described above if only sources of the elemental constituents present in dissolved form and/or colloidally dissolved sources are used. As already mentioned, a starting compound can be a source for only one or for several elementary constituents. In a corresponding manner, a solution or colloidal solution listed above can have dissolved only one or more elementary constituents of the relevant shaped solid catalyst body to be produced. As already mentioned, the preferred solvent is water. The resulting aqueous mixtures are preferably dried by spray drying.

If this document speaks of a solution of a source (starting compound, starting substance) in a solvent (particularly water), the term “dissolving” is meant in the sense of a molecular or ionic solution. This means that the largest geometric unit of the dissolved starting substance (source) in the solution necessarily has “molecular” dimensions, and the solution appears “visually empty”.

In contrast, colloidal solutions represent a connection between real (molecular and/or ionic) solutions and suspensions. These colloidally disperse systems contain smaller accumulations of molecules or atoms, which, however, cannot be seen with the naked eye or with a microscope. The colloidal solution appears optically completely clear (although often colored) because the particles it contains only have a diameter of 1 to 250 nm (preferably up to 150 nm and particularly preferably up to 100 nm).

Due to the small size, separation of the colloidally dissolved particles by conventional filtration is not possible. However, they can be separated from their “solvent” by ultrafiltration using membranes of plant, animal or artificial origin (e.g. parchment, pig bladder or cellophane). In contrast to the “optically empty” real (molecular and/or ionic) solutions, a beam of light cannot pass through a colloidal solution without being deflected. The light beam is scattered and deflected by the colloidally dissolved particles. In order to keep colloidal solutions stable and prevent further particle agglomeration, they often contain wetting and dispersing aids as well as other additives.

While elements other than silicon (elementary constituents) of a solid catalyst molding are preferably introduced from sources dissolved in the form of a solution (particularly preferably in an aqueous solution) to produce the wet (preferably aqueous) mixture M, the element silicon is preferably in the form of a silica sol to produce the wet (preferably aqueous) mixture M.

Silica sols are aqueous colloidal solutions of almost spherical polysilicic acid particles. The diameter of the particles is in the colloid range and, depending on the type, is 5 to 75 nm. The particles are pore-free. They have a core made of SiÜ2, which is hydroxylated on its surface. The spherical individual particles are not cross-linked with each other. For reasons of stability, a subset of the hydroxyl groups in silica sols is often present in a form neutralized with alkali metal hydroxide and/or ammonium hydroxide. This means that the counterions are then sometimes not protons, but alkali ions (for example Na ⁺ ) and/or NH4 ⁺ cations. The SiO2 content of silica sols suitable for producing a wet (preferably aqueous) mixture M can be, for example, 30% to 60% of the weight of the silica sol. Silica sols are normally water-liquid and do not contain any sedimentable components. They often last for years without sedimentation.

Particularly suitable Si sources are the LUDOX® silica sols from Grace GmbH & KG, In der Hollerecke 1, D-67545 Worms. Their particles are discrete, uniform spheres of silicon dioxide with no internal surface or detectable crystallinity. The majority of them are dispersed in an alkaline medium, which reacts with the hydroxylated surface and produces repulsive negative charges.

The particle diameters of suitable silica sols can be very narrow (essentially monodisperse) or very wide (polydisperse). A silica sol that is particularly suitable for the purposes according to the invention (for producing a wet (preferably aqueous) mixture M) is the LUDOX TM50 silica sol from Grace. The LUDOX TM50 silica sol has a largely monodisperse (d = 22 nm) particle diameter distribution. Its pH value (1 atm, 25°C) is 9.0. The alkali ion that replaces a subset of the hydroxyl protons is Na ⁺ . The SiC>2 content of LUDOX TM50 is 50% of the weight of this hydrogel. The specific surface area of the colloidally dissolved SiO2 particles contained in LUDOX TM50 is 140 m ² /g. The mass density (1 atm, 25°C) of LUDOX TM50 is 1.40 g/cm ³ . The titratable alkali content of LUDOX TM50 (calculated as Na2Ü) is 0.21% by weight (based on the weight of the silica sol).

The dynamic viscosity of LUDOX TM50 is 40 mPas (1 atm, 25°C). The CI' content (calculated as NaCI) of LUDOX TM50 is 0.03% by weight and the SO4 ² 'content of LUDOX TM50 (calculated as Na2SÜ4) is 0.08% by weight (each based on the weight of LUDOX TM50).

Of course, in a solution to be used to produce a wet (in particular aqueous) mixture M, at least one element source can also be present in molecular and/or ionically dissolved form and one or more than one other element source can be colloidally dissolved next to one another.

A favorable source of Mo is ammonium heptamolybdate tetrahydrate. This is mainly because it has excellent solubility in water. According to Ullmann's Encyclopedia of Industrial Chemistry, Volume 22, 2003, WILEY-VCH, pages 320/321, a solution of ammonium molybdate tetrahydrate in water at 25 ° C and 1 atm has a saturation solubility of 30% by weight (calculated as an anhydrous salt).

Due to the manufacturing process, ammonium molybdate tetrahydrate can be contaminated in small amounts (usually ppm) with water-insoluble isopolymolybdate (as a result of process parameters not being strictly adhered to during its production). If contaminated ammonium heptamolybdate tetrahydrate is dissolved in water in this way, an aqueous solution is formed which has a certain turbidity due to the small amounts of undissolved, finely divided isopolymolybdate. The applicant's own investigations have shown that even ammonium molybdate tetrahydrate contaminated with isopolymolybdate, the solution of which in water (determined as described in WO 2016/147324) has a turbidity of 20 NTU, or 50 NTU, or 70 NTU, or 100 NTU, or of 150 NTU, or of 200 NTU, or of 250 NTU, or of 300 NTU, is suitable for the production of solid catalyst moldings according to the invention, without their performance when used as catalysts for the heterogeneously catalyzed partial gas phase oxidation of propene to acrolein as the main product and acrolein noticeably impaired as a by-product.

Other suitable Mo sources are, for example, ammonium orthomolybdate ((NH4)2MoO4), ammonium dimolybdate ((NH ₄ )2Mo ₂ O7), ammonium tetramolybdate dihydrate ((NH ₄ )2Mo ₄ Oi3 x 2 H2O) and ammonium decamolybdate dihydrate ((NH4)4MOIOOS2 x 2 H2O). ). In principle, molybdenum trioxide can also be used.

The preferred source of alkali metals in the context of the production of shaped unsupported catalyst bodies are their hydroxides. In principle, the nitrates of these elements and the hydrates of these nitrates also come into consideration as such sources. This means that the preferred K source is KOH, but in principle KNO3 or its hydrate can also be used as a K source.

Salts of bismuth, which have the Bi as Bi ³⁺ , are preferably used as the Bi source. Possible salts of this type are, for example, bismuth (III) oxide, bismuth (III) oxide nitrate (bismuth subnitrate), bismuth (III) halide (for example fluoride, chloride, bromide, iodide) and in particular bismuth (III) nitrate pentahydrate. Of course it can be used as a bi-source a solution of elemental Bi in aqueous nitric acid can also be used, in which the Bi is present as Bi ³⁺ . In the case of using (preferred according to the invention) an aqueous solution of Bi ³⁺ nitrate or its hydrate as a source (such a solution can also be produced by dissolving elemental Bi in aqueous nitric acid), it is advantageous according to the invention if its pH value ( 1 atm, 25°C) is low, as this counteracts the undesirable formation of precipitates containing Bi ³⁺ in the aqueous solution. This pH value is preferably <1, particularly preferably <0.5. As a rule, this pH value is > -2, usually > 0. Such an aqueous solution is expediently nitric acid. That is, their low pH is caused by excess nitric acid (in this case the molar ratio (HNOS-) / (nßj ₃ +) is of the molar amount of NO ₃ 'contained in the aqueous solution (n _N os-) to the molar amount of Bi ₃ ⁺ contained in the aqueous solution (nßj ₃ +) > 3).

Preferred Fe sources are salts of Fe ³⁺ , among which the various iron (III) nitrate hydrates are particularly preferred (compare, for example, DE 10 2007 003076 A1). According to the invention, iron (III) nitrate nonahydrate is particularly preferably used as the Fe source for the aforementioned purpose. Of course, salts of Fe ²⁺ can also be used as an Fe source.

To produce the solid catalyst moldings, based on the total molar amount of Fe contained in them, at least 50 mol%, better at least 75 mol% and preferably at least 95 mol% or 100 mol% are introduced in the form of an Fe source, which has the Fe as Fe ³⁺ . Fe sources that contain both Fe ³⁺ and Fe ³⁺ can also be used for this purpose.

Well-suited sources of Co are, in particular, its salts, which have the Co as Co ²⁺ and/or Co ³⁺ . Examples of such examples include cobalt(II) nitrate hexahydrate, Co ₃ O4, CoO, cobalt(II) formate and cobalt(II) nitrate. The former of these sources is particularly preferred for the aforementioned purpose. Of course, a solution of elemental Co in aqueous nitric acid, in which the Co is present as Co ²⁺ , can also be used as a Co source.

In the case of the elemental constituent Ni, Ni ²⁺ salts are preferably used. As such, in particular nickel(II) carbonate, nickel(II) sulfate, nickel(II) oxide, nickel(II) acetate, nickel(II) formate, nickel(II) hydroxide, nickel(II) oxalate and nickel(II) nitrate and the respective hydrates of these salts. Hydrates of nickel(II) nitrate (for example its hexahydrate) are particularly preferably used as Ni sources.

To improve the solubility of, for example, salts of Fe, Co and/or Ni in an aqueous medium, ammonia (also as its aqueous solution) and/or nitric acid (in particular as its aqueous solution) can be added to the respective solution as required.

In principle, the production of a wet (for example aqueous) mixture M can take place in a wide variety of gas atmospheres (for example air, argon, nitrogen, water vapor and/or carbon dioxide). According to the invention, a wet (for example aqueous) mixture M is preferably produced in air (the aqueous mixture M is advantageously saturated in air). This is particularly true if salts of Co ²⁺ and salts of Fe ²⁺ are used as cobalt and iron sources. Especially when these salts are nitrates and/or their hydrates.

As already mentioned, according to the invention the wet mixture M is preferably an aqueous mixture M, which is particularly advantageously prepared in the following manner. An aqueous solution A is prepared from at least one source of the element Fe, from at least one source of the element Bi, from at least one source of the element Co and optionally at least one source of the element Ni, the pH value of which is <3, preferably <2, particularly preferably <1 and very particularly preferably <0 (pH values of aqueous solutions in this document generally (unless explicitly stated otherwise) refer to a measurement with a glass electrode designed as a combination electrode at 1 atm and at the temperature at which the respective aqueous solution is prepared; the required calibration of the combination electrode is carried out under the same conditions using aqueous buffer solutions whose pH value is known under these conditions and is close to the desired measured value; the pH value is particularly suitable for determining such pH values Mettler Toledo pH electrode Inpro 4260/425/Pt 100, which is a combination electrode with an integrated Pt 100 temperature sensor for automatic temperature compensation). As a rule, the pH of the aqueous solution A is not less than -2 and is particularly advantageously in the range -1 to 0. The aqueous solution A is preferably an aqueous solution of the nitrates or nitrate hydrates of the aforementioned elements. The aqueous solution A is particularly preferably an aqueous solution of these nitrates or nitrate hydrates in aqueous nitric acid. Solutions of the relevant elements in aqueous nitric acid are also suitable as element sources, particularly for producing such a solution.

An aqueous solution B is prepared from at least one source of the element Mo and optionally at least one of the sources of an alkali metal. The pH value of the aqueous solution B is advantageously (at 1 atm and the temperature at which the solution B is produced) <7. The pH value of the aqueous solution B is particularly preferably <6.5 and very particularly advantageously <6 As a rule, the pH value of the aqueous solution B will be > 3. Cheap solutions B to be used according to the invention have a pH of 4 to 6. According to the invention, the element hydroxide (for example KOH) is preferably used as a source of an alkali metal to prepare the aqueous solution B. The preferred Mo source for preparing an aqueous solution B is ammonium heptamolybdate tetrahydrate ((NH4)6Mo?O24 x 4 H2O), which is completely soluble in water at 25 ° C (1 atm) up to saturation solubility (30% by weight, calculated anhydrous).

The total content of the aqueous solution A of the metal constituents Bi, Fe, Co, Ni, etc. According to the invention, is expediently 5 to 20% by weight, advantageously 10 to 15% by weight, based on the total amount of the aqueous solution A.

According to the invention, the total content of Mo in the aqueous solution B is expediently, based on the total amount of the aqueous solution B, 2 to 25% by weight, advantageously 3 to 20% by weight and particularly advantageously 5 to 15% by weight.

The aqueous solution A and the aqueous solution B are then expediently mixed with one another. It is advantageous to proceed in such a way that the aqueous solution A is continuously stirred into the aqueous solution B. The aqueous solution B presented is advantageously stirred intensively.

The total content of the resulting aqueous mixture of aqueous solution A and aqueous solution B of the metal constituents Bi, Fe, Co, Ni, Mo, etc. according to the invention, based on the total amount of the aqueous mixture, is expediently 3 to 20% by weight, advantageously 5 to 15% by weight.

The temperature of the aqueous solution B presented and that when the aqueous solution A is stirred in, as well as the temperature of the aqueous solution A itself, is advantageously (preferably during the entire mixing process) <80 ° C and > 0 ° C. The aforementioned temperatures are preferably <75°C and >30°C, and particularly preferably they are <70°C and >50°C or <65°C and >55°C. Advantageously, the aqueous solutions A and B as well as the aqueous mixture resulting when the aqueous solution A is stirred into the aqueous solution B have the same temperature. This is best 60°C. Preferably, the temperatures of the aqueous solution A, the aqueous solution B and the aqueous mixtures resulting from these are constant over the course of the stirring process described. For this purpose, thermostatization can be carried out, for example, using a water bath. When stirring the aqueous solution A into the aqueous solution B, the working pressure is expediently 1 atm (1.01 bar).

The aqueous solution A is preferably stirred into the aqueous solution B presented within a period of 5 to 60 minutes, more preferably within a period of 10 to 30 minutes and most preferably within a period of 15 to 25 minutes. The resulting aqueous mixture is subsequently stirred, preferably while maintaining the stirring temperature, expediently for 5 to 60 minutes, preferably 10 to 30 minutes and particularly advantageously for 15 to 25 minutes.

The pH value of the aqueous mixture of the aqueous solution A and the aqueous solution B is advantageously <3, better <2. As a rule, it is values >0.

If the unsupported shaped catalyst body contains the elemental constituent Si, then according to the invention, aqueous silica sol is preferably stirred into the aqueous mixture of aqueous solution A and aqueous solution B as the source of the same, water can advantageously be added to this aqueous mixture before this stirring. Both the aqueous silica sol and the water can expediently be added at once. Both the temperature of the water and the temperature of the aqueous silica sol advantageously correspond to the temperature of the aqueous mixture of the aqueous solution A and the aqueous solution B. Finally, stirring is expediently continued for up to 30 minutes. The aforementioned temperature is advantageously maintained during subsequent stirring. The SiO2 content of the added aqueous silica sol can be 15 to 60% by weight, or 20 to 60% by weight, or 30 to 60% by weight, preferably 40 to 60% by weight and particularly preferably 45 to 55% by weight .-% (based on its total weight).

Instead of placing the aqueous solution B in a thermostated stirred container and then allowing the aqueous solution A to run into the same while stirring, both the aqueous solution B and the aqueous solution A can also be fed continuously to the stirred container (for example by a " 3-way T-mixer). In principle, the aqueous solution B can also be continuously stirred into an aqueous solution A provided. However, this procedure is less preferred.

As a rule, the aqueous mixture M obtainable as described is an aqueous suspension (preferably the ratios V described as advantageous are also present in the aqueous mixture M (total molar amount of NH3 + NH4 ⁺ contained to molar amount of Mo contained) ; In addition, the pH value of the aqueous mixture M obtainable as described is also advantageously <3, generally 0 to 2). Aqueous mixtures M available as described advantageously contain no more or less than 60 mol% of the total molar amount of Co and/or Ni contained in them in dissolved form in the aqueous medium (at the temperature and working pressure at which the aqueous mixture produces M became). Preferably, the proportion AT of the molar amount of Co and/or Ni contained in the aqueous mixture M as a whole, dissolved in the aqueous medium of the aqueous mixture M, is at values <50 mol% and particularly preferably at values <40 mol%. , or <30 mol% or <20 mol%. According to the invention, the total content of Bi, Fe, Mo, etc. in the aqueous mixture M to be dried (preferably spray-dried) is expedient, based on the Amount of the aqueous mixture M, 3 to 20% by weight, advantageously 5 to 15% by weight. As a rule, AT is > 10 mol% or < 15 mol%.

According to the invention, the aqueous mixture M is converted into a finely divided, intimate dry mixture preferably by spray drying the aqueous mixture M (the aqueous mixture M is preferably dried as close as possible to its production). This means that the aqueous mixture M is first divided into finely divided droplets (sprayed) in a spray dryer and then dried in the spray dryer. Spray drying is preferably carried out in a stream of hot air. In principle, other hot gases can also be used for the aforementioned spray drying (for example nitrogen or air diluted with nitrogen and other inert gases).

Spray drying can take place both in cocurrent and in countercurrent of the droplets to the hot gas. Typical gas inlet temperatures are in the range from 250 to 450°C, preferably 270 to 370°C. Typical gas outlet temperatures are in the range from 100 to 160°C. Spray drying is preferably carried out in cocurrent flow of the droplets to the hot gas.

The average particle diameter of the resulting spray powder is typically 10 to 100 pm, preferably 15 to 60 pm and particularly preferably 25 to 50 pm (the diameter is determined according to ISO 13320-1 by means of light scattering on spray powder dispersed in air (dispersing air pressure 1.0 bar In general, references in this document to a standard refer to the edition of the standard that was in force on the priority date of this patent application and whose publication date (issue date) has the smallest time difference to the priority date of this patent application.

The shaken mass density (25°C, 1 atm) of the spray powder is typically 500 to 1300 g/l and preferably 700 to 1100 g/l.

The ignition loss of the spray powder (annealing for 3 hours at 600 ° C (powder temperature) under standing, excess air) is typically 20 to 40% by weight, preferably 25 to 35% by weight, of its initial weight.

Until it is processed further, the spray powder can preferably be temporarily stored in airtight containers (for example barrels made of plastic). The storage temperature should not exceed 70°C and is preferably <50°C. As a rule, the storage temperature will not fall below 10°C. Since the spray powder is usually hygroscopic, extensive contact with moist air should be avoided. Contact with moist air can impair the handling properties of the spray powder (for example its flowability) and ultimately reduce the catalytic activity of the solid catalyst moldings produced with it.

Of course, the aqueous mixture M can also be dried by other drying methods, for example conventional evaporation (preferably at reduced pressure; the drying temperature will generally not exceed 150 ° C). In principle, an aqueous mixture M can also be dried by freeze-drying or Spin-Flash® drying.

The spray powder, for example, is initially coarsened by subsequent compaction. If the compaction is carried out dry, fine-particle graphite and/or other shaping aids mentioned in this document (for example lubricants, reinforcing agents and/or pore formers) can be mixed into the spray powder before compaction (for example with a rotary wheel mixer). For example, compaction can be carried out with a calender having two counter-rotating steel rollers become. The compact can then be comminuted to the appropriate particle size for the intended further use. This can be done in the simplest way, for example, by pressing the compact through a sieve with a defined mesh size.

In principle, compaction can also be carried out wet. For example, the spray powder can be kneaded with the addition of water. Following kneading, the kneaded mass can be comminuted to the desired fine particle size for subsequent use (see e.g. DE 10049 873 A1) and dried.

Precursor moldings of regular or irregular geometry are formed from the finely divided precursor mass (from the finely divided intimate dry mixture of the sources of the elemental constituents) by compacting (compressing or compacting) and the solid catalyst moldings are then produced by thermal treatment.

As further fine-particle shaping aids, lubricants such as graphite, carbon black, polyethylene glycol, polyacrylic acid, stearic acid, starch, mineral oil, vegetable oil, water, boron trifluoride and/or boron nitride can be added to the fine-particle precursor mass beforehand and/or during shaping. Reinforcing agents such as microfibers made of glass, asbestos, silicon carbide or potassium titanate can also be considered as shaping aids, which have a beneficial effect on the cohesion of the resulting compact (the resulting molded body) after the shaping has been completed by compression. Pore formers such as ammonium nitrate, ammonium carbonate, water and/or malonic acid can also be considered as shaping aids. The pore formers decompose or evaporate to form pores during the thermal treatment. The use of lubricants as part of a corresponding shaping can be found, for example, in the documents DE 10 2007 004961 A1, WO 2008/087116, WO 2005/030393, US 2005/0131253, WO 2007/017431, DE 102007 005606 A1 and in the DE 10 2008 040093 A1 described.

Preferably, only finely divided graphite is used as a lubricant. Particularly suitable fine-particle graphites to be used are those recommended in WO 2005/030393, US 2005/0131253, WO 2008/087116 and DE 10 2007 005606 A1. This applies in particular to those graphites that are used in the examples and comparative examples in these documents. Particularly preferred graphites are Asbury 3160 and Asbury 4012 from Asbury Graphite Mills, Inc. , New Jersey 08802, USA and Timrex®T44 from Timcal Ltd., 6743 Bodio, Switzerland.

Based on the weight of the finely divided precursor mass to be molded, it can contain, for example, up to 15% by weight of finely divided lubricant (for example graphite), based on its total weight. However, the lubricant content in the finely divided precursor mass to be molded (in the finely divided intimate dry mixture) is usually <9% by weight, often <5% by weight, often <4% by weight; This is particularly true if the finely divided lubricant is graphite. As a rule, the aforementioned additional amount is > 0.5% by weight, usually > 2.5% by weight.

As a rule, the fine-particle precursor mass (the fine-particle intimate dry mixture) containing optional shaping aids is compacted to the desired geometry of the precursor molding by the action of external forces (pressure) on the precursor mass. The shaping apparatus to be used or the shaping method to be used is not subject to any restrictions.

For example, the compacting shaping can be done by tableting. The finely divided precursor mass (the finely divided, intimate dry mixture) is preferably used dry to the touch. However, for example, it can still hold up to 10% of its total weight Contain added substances that are liquid under normal conditions (25 °C, 1 atm (1.01 bar)). The finely divided precursor mass (the finely divided intimate dry mixture) can also contain solid solvates (eg hydrates) which have such liquid substances in chemically and/or physically bound form. Of course, the finely divided precursor mass can also be completely free of such substances.

The preferred shaping process by compacting the finely divided precursor mass (the finely divided, intimate dry mixture) is tabletting. The basic principles of tableting are described, for example, in “The Tablet”, Handbook of Development, Manufacturing and Quality Assurance, W.A.Ritschel and A. Bauer-Brandl, 2nd edition, Edition Verlag Aulendorf, 2002 and can be transferred to a tabletting process according to the invention in a completely corresponding manner .

Tableting is a process of press agglomeration. The free-flowing feed mixture is inserted into a pressing tool with a die between two punches and compacted by uniaxial compression and formed into a solid compacted body. Tableting can be divided into four parts: metered introduction, compaction (elastic deformation), plastic deformation and ejection. Tableting is carried out, for example, on rotary presses or eccentric presses.

The outer surface of the tableted catalyst carrier consists of a peripheral surface corresponding to the inner wall of the die cavity and a first face surface and a second side surface corresponding to the operative heads of the punches. The tableted catalyst support can be flat or have curved ends, i.e. at least one of the first side surfaces and the second side surface are curved. Curved side surfaces can be obtained, for example, by using a concave lower and/or upper punch. If desired, the upper punch and/or the lower punch may include projecting pins to form internal passages. It is also possible to provide the press punches with a large number of pins, so that a punch can be produced with four pins, for example, in order to produce moldings with four holes (passages). Typical design features of such pressing tools can be found, for example, in US 8,865,614.

Press tools typically consist of a die, an upper punch, a lower punch, and pins (if the formed body has passages). Suitable materials for pressing tools are tool steels, hard metals based on tungsten carbide (WC) and ceramic materials. Tool materials with a hardness greater than 55 on the Rockwell C scale are preferred. Examples of tool steel materials are the DIN tool steels 1.2210, 1.2343, 1.2436, 1.2379, 1.2601, 1.2080, 1.25550 as well as high-speed steels, Vanadis 4 Extra from Uddeholm D-40549 Düsseldorf, Vanadis 8 from Uddeholm D-40549 Düsseldorf. Suitable WC-based materials are described in US8,865,614. Examples of such WC-based materials are G10-Ni from Hartmetall® Gesellschaft in D70497 Stuttgart and htc-KR17® from Hightech-Cerarn®. Examples of ceramic materials are yttrium-stabilized zirconium oxide (YSZ).

WC-based hard metals and ceramic materials are particularly suitable for tool use in which a lined die made of WC-based hard metal or ceramic is inserted into a steel housing made of tool steel, e.g. 1.2379.

The pressing tool usually has a surface coating to improve surface hardness, corrosion resistance, wear resistance, friction and non-stick properties. Examples of surface coating types include diamond such as carbon (DLC), boron nitride, titanium nitride, chromium nitride, plasma chrome plating, hard chrome plating. The thickness of the layer layer is 1 to 10 pm, preferably 1 to 5 pm. The surface of pressing tools that come into contact with the feed mixture and the resulting tablet preferably has a low surface roughness. The arithmetic mean roughness value Ra according to DIN 4768 of pressing tool surfaces should preferably be 0.01 to 0.5 pm, particularly preferably 0.02 to 0.3 pm, even more particularly preferably 0.02 to 0.2 pm, very particularly preferably 0.02 to 0.1 pm.

The length of the tip of the lower punch is preferably 2 to 7 mm, particularly preferably 2 to 6 mm, very particularly preferably 2.5 to 5 mm. Tip straight lines that are too high can lead to high friction, especially if the precursor molded body sticks together. It is preferred that the upper and lower edges of the tip of the lower stroke are not rounded but sharp. The sharp edge mitigates powder jamming into the gaps at the punch-punch interface and the pin-hole interface (on tablet molds with passages). Powder clamping results in both sticking and powder leakage.

The length of the tip of the upper punch is preferably greater than 2 mm and is typically in the range of 2 to 10 mm. In contrast to the lower punch, a high tip straight length does not cause friction problems because the upper punch is only inserted a few millimeters into the die in the tableting cycles.

If the tablet mold has passages, the bottom punch and top punch will have holes to accommodate the pins. The top punches should have at least one vent hole that allows air to escape from the die cavity through the top punch holes to the outside of the top punch holes during compression. Such upper punches with vent hole(s) are specified in US 2010/0010238 (see Figs. 4a, 4b, 4c and 4d).

The distance between the nozzle bore and the lower outer punching surface is preferably 3 to 50 pm, particularly preferably 5 to 35 pm, very particularly preferably 6 to 26 pm. Analogously, the distance between the die hole and the upper outer punching surface is preferably 3 to 50 pm, particularly preferably 5 to 35 pm, very particularly preferably 6 to 26 pm. The clearance is ensured by selecting an appropriate combination of the dimensional tolerances of the die and the lower punch. The dimensional tolerance is typically represented according to the ISO shaft tolerance defined in ISO 286-2. Examples of the combinations of the dimensional tolerance of the nozzle bore and the outside of the punch shown in ISO tolerance codes are H6/f7, H6/g6, H6/g7, H7/g6, H7/f7, F8/h6, G7/h6, F7/h6 (nozzle bore /lower punching outside).

In cases where the tablet mold has passages, the pressing tool includes pins. The distance between the pin bore of the lower punch and the pin is preferably 3 to 50 pm, particularly preferably 5 to 35 pm, very particularly preferably 6 to 26 pm. Analogous to the distance between the die bore and the punching outside, this distance is ensured by choosing a suitable combination of the dimensional tolerances of the die and the lower punch.

The die bore preferably has a slight taper that starts from a defined depth towards the top of the die. The tapered portion of the nozzle bore has a gradual increase in bore size toward the top of the nozzle, creating additional clearance between the nozzle bore wall and the sharply straight outer side surface of the lower punch. The additional space makes it easier to vent the air contained in the compound feed during compression in the die, thereby mitigating powder blow-off and resulting unstable tableting due to poor air venting. Another advantage of conical dies is the ease of ejection after compaction. Compression into a tablet at the point where the die bore has a taper results in a Tablet with slightly tapered outer side surface due to the embossing of the conical die bore. In the ejection phase, in which the lower punch pushes the tablet upwards in the die, the ejection of the tablet from the die wall occurs easily, as a slight lifting of the tablet forces the tablet to detach from the die wall due to the tapered structure. If the die bore has no taper, the separation of the tablet from the die wall does not occur, so the entire ejection process (i.e. pushing the tablet up from the depth at which compression occurred to the die top) occurs under the friction between the outer surface the tablet and the die wall and between the straight outside of the tip and the nozzle wall suffers. The friction leads to an unfavorably high ejection force.

The depth (i.e. depth from the die top) of the die taper should be chosen so that the formed tablet is predominantly in the conical zone before ejection. To realize such a situation, the depth of die taper can be oriented by summing the height of the in-die tablet before elastic recovery (i.e., minimum distance between the upper and lower punches) and the insertion depth of the upper punch. For example, a taper depth of 12 to 15 mm can be used for an in-die tablet height of 12 mm with a top punch insertion depth of 2 mm.

The angle of the die taper is typically 0.1 to 0.6°, and the size increase of the die bore on the upper side is preferably 0.03 to 0.2 mm, particularly preferably 0.05 to 0.14 mm. The increase in size can be derived mathematically from the angle of the taper and the depth of the taper.

In cases where the tablet mold has passages, the pressing tool includes pins. The pins are attached to the turret so that the pins are in the die cavity where the tablet is formed to exit the passages of the tablet. Similar to the dies, the pins do not move vertically during the tabletting cycle, unlike the upper and lower punches. The vertical plane of the top end of the pins is equal to or slightly below the height of the top face of the die. Especially in cases where the tablet has curved side surfaces, where the lower punching surface has a concave surface, the vertical plane of the upper end of the pin should be slightly below the level of the upper front of the dies so that the pins do not come out of the lower punching surface stand out.

In cases where the tablet mold has passages, sticking on the surface of the pins often occurs, resulting in disadvantages such as high ejection force due to high friction at pin-tablet interfaces. The problem is particularly pronounced in multi-gang forms with multiple pins. Typically the pins show a higher tendency to stick than the die wall and the tip of just the bottom punch.

In cases where the tablet form has passages, the pins preferably have a slight taper at the top for a defined length. The tapered part of the pins shows a gradual reduction in pin diameter towards the top of the pin. The main advantage of the conical pins is the ease of ejection after compaction. Compression into a tablet at the point where the pins have a taper results in tablet passages with a slightly tapered inner side surface as a result of the embossing by the tapered pins. The diameters of the tablet passages decrease slightly from bottom to top along the axial axis. In the ejection phase, in which the lower punch pushes the tablet upwards in the die while the pins and die remain vertically stationary, the tablet is ejected from the pins easily, as a slight lifting of the tablet causes the tablet to detach from the die pins due to the tapered structure. If the pins do not have a taper, the separation of the tablet from the pins does not occur, so the entire ejection process (i.e Pushing the tablet up from the depth at which compression occurred on the upper face of the die) suffers from friction at the tablet pin interfaces, resulting in high ejection force. The tapered pins are particularly advantageous when the tablet has multiple passes.

The length of the taper of the pins should be chosen so that the formed tablet is predominantly in the conical zone before ejection. To realize such a situation, the length of taper of the pins can be oriented by summing the height of the in-die tablet before elastic recovery (i.e., minimum distance between the upper and lower punches) and the insertion depth of the upper punch. For example, a tapered length of 12 to 15 mm can be used for an in-die tablet height of 12 mm with a top punch insertion depth of 2 mm.

The die taper angle is typically 0.1 to 0.6°, and the reduction in pin diameter at the top is preferably 0.05 to 0.3 mm, particularly preferably 0.1 to 0.2 mm. The reduction can be derived mathematically from the angle of the taper and the taper length.

The industrial mass production of the tablets is preferably carried out on a rotating tablet press. Commercially available rotary presses can be used for this invention. Examples of rotary tablet presses include Korsch XT-600 HD, Korsch XT-600, Korsch TPR 700, Korsch TRP 1200, Korsch XL 400 MFP, Kilian RX and Kilian Synthesis.

Rotary presses typically have two compaction rolls to perform two-stage compaction, which includes pre-compaction and main compaction. The main compression pressure is in the range from 5 to 500 MPa, preferably 8 to 400 MPa, particularly preferably 10 to 300 MPa. The pre-compression pressure is typically in the range from 5 to 50%, preferably 7 to 40%, particularly preferably 10 to 35% of the main compression pressure applied.

The pressing tool is selected according to the desired geometric dimensions of the compacted body. The size and shape of the compressed body and thus of the catalyst is selected so that suitable packing of the catalyst bodies obtained from compressed bodies in a reactor tube is possible. The catalysts obtained from the compacted bodies suitable for the catalysts according to the invention are preferably used in reactor tubes with a length of 6 to 14 m and an inner diameter of 20 mm to 50 mm. In general, the carrier consists of individual bodies with a maximum dimension in the range of 3 to 20 mm, such as 4 to 15 mm, in particular 5 to 12 mm. The maximum extension is the longest straight line between two points on the outer circumference of the beam.

The shape of the compacted bodies is not particularly limited and can be in any technically feasible shape, depending, for example, on the forming process. For example, the support may be a solid tablet or a hollow tablet such as a hollow cylinder. In a further embodiment, the support can be characterized by a multi-lobe structure. A multi-lobe structure is intended to refer to a cylinder structure that has a large number of cavities, e.g. grooves or grooves, which run in the cylinder periphery along the cylinder height. In general, the cavities are arranged substantially equidistantly around the circumference of the cylinder.

The pressing force during tabletting influences the compaction of the free-flowing feed mixture and thus, for example, the density and/or mechanical stability of the compacted body. In practice, it has proven to be useful to specifically adjust the lateral compressive strength of the tableted catalyst carrier by selecting the appropriate pressing force and to check it through spot checks. For the purposes of the present invention, the lateral Compressive strength is the force that breaks the tableted catalyst support located between two flat parallel plates, with the two flat parallel end faces of the catalyst support at right angles to the flat parallel plates.

To improve the tableting properties, the free-flowing feed mixture can be subjected to further processing, for example by sieving, preheating and/or pre-granulating, i.e. pre-compacting. A roller compactor, such as a Chilsonator® from Fitzpatrick, can be used for pre-granulation.

Further information on tabletting, in particular on pre-granulation, screening, lubricants and tools, can be found in WO 2010/000720. Further information on tabletting can be found in the Handbook of Powder Technology, Chapter 16: Tableting, K. Pitt and C. Sinka, Vol 11, 2007, pp. 735 to 778.

Tableting is advantageously carried out as described in the documents WO 2005/030393, DE 102008 040093 A1, DE 102008 040094 A1 and WO 2007/017431. The temperature surrounding the tabletting machine is normally 25 °C. The particle diameters of the precursor mass to be compacted (the finely divided, intimate dry mixture), optionally as a result of pre-coarsening by compacting, are expediently in the range 100 to 2000 pm, preferably 150 to 1500 pm, particularly preferably 400 to 1250 pm, or 400 to 1000 pm, or 400 to 800 pm (shaping aid mixed in before compaction is not taken into account).

Just like the shaping apparatus to be used for compaction or the shaping method to be used, the desired geometry of the resulting shaped bodies is also not subject to any restrictions in the method according to the invention.

A preferred ring geometry (the geometry of a non-calcined green body and the solid catalyst molding resulting from this by calcination are usually essentially the same) is the geometry 5 mm x 5 mm x 2 mm (outer diameter x height (length) x inner diameter). This is because fixed catalyst beds made of rings of this geometry cause a particularly low pressure loss in the reaction gas mixture flowing through the fixed catalyst bed (particularly in reaction tubes with an inner diameter of 22 mm to 30 mm). A low pressure loss is particularly advantageous if the partial oxidation catalyzed by the fixed catalyst bed is operated at a high load on the fixed bed with reaction gas mixture (at a high current intensity of the reaction gas mixture flowing through the fixed catalyst bed). Another preferred ring geometry (it has advantageous pouring behavior, particularly in reaction tubes with a smaller inner diameter (for example 20 mm)) is the geometry 5 mm x 3 mm x 2 mm (outer diameter x height (length) x inner diameter). Of course, all those geometries that are disclosed and recommended in WO 02/062737 and in WO 2015/067656 can also be considered.

Particularly in the case of annular precursor moldings (precursor moldings are also referred to as green compacts in the literature, regardless of their shape), the shaping compression should advantageously be carried out in such a way that the lateral compressive strength SDF _V of the resulting molding (cf. DE 102008 040093 A1, DE 102008 040094 A1 and WO 2005/030393) the relation 5 N <SDF _V <100 N, preferably 8 N <SDF _V s 80 N, and particularly preferably 12 N <SDF _V <50 N is fulfilled.

The experimental determination of the lateral compressive strength is carried out as described in the documents WO 2005/030393 and WO 2007/017431. Of course, ring-like green bodies, as recommended by DE 102008 040093 A1, are particularly preferred according to the invention. The end faces of ring-shaped or ring-like shaped bodies can be used in the described manufacturing process of green compacts according to the invention (both or only one of the two end faces) can be flat or curved (curved) outwards (convex) (see in particular DE 102007 004961 A1, EP 0 184 790 A2, DE 102008 040093 A1 (for example its paragraph [0032]) and DE 102008 04009 A1 (for example its paragraph [0074]) and the individualized embodiments presented in these documents). When determining/specifying the height of such geometric shapes, such a convex curvature (curvature) is generally not taken into account in this document. Rings or ring-like shaped bodies with convexly arched (curved) end faces (preferably both end faces have the same curvature (curvature)) are advantageous in that fixed catalyst beds of ring-shaped or ring-like shaped bodies with a convexly arched (curved) end face (with otherwise the same geometry). lower pressure loss in the reaction gas mixture flowing through the fixed catalyst bed (especially in the case of fixed catalyst beds in reaction tubes) than fixed catalyst beds of annular or ring-like shaped bodies with a flat end face. This applies in particular if the ring geometry is 5 mm x 5 mm x 2 mm (outer diameter x height (length) x inner diameter). The radius of such a convex curvature is usually 0.4 to 5 times (e.g. 0.8 to 4 times, or 1.2 to 3 times, or 1.6 to 2 .6 times) the outer diameter of the circular cylinder of the catalyst ring. As already mentioned, a fixed catalyst bed that causes a lower pressure loss is particularly advantageous if the partial oxidation catalyzed by the fixed catalyst bed is operated at a high load on the fixed bed with reaction gas mixture (at a high current intensity of the reaction gas mixture flowing through the fixed catalyst bed).

Particularly advantageous ring geometries of shaped bodies obtainable by compacting finely divided precursor mass (finely divided, intimate dry mixture) meet the condition of height (length)/outer diameter = H/A = 0.3 to 1.5 or up to 1.2. H/A = 0.5 to 1.1 or up to 1.0 is particularly preferred. Furthermore, for ring-shaped or ring-like green bodies according to the invention, it is favorable if the ratio l/A (where I is the inner diameter of the ring geometry) is 0.3 to 1.5, preferably 0.6 to 1.1.

The aforementioned ring geometries are particularly advantageous if they simultaneously have one of the advantageous H/A ratios and one of the advantageous I/A ratios. Such possible combinations are, for example, H/A = 0.3 to 1.5 or up to 1.2 and l/A = 0.3 to 1.5 or 0.6 to 1.1. Alternatively, H/A can be 0.5 to 1.1 or up to 1.0 and l/A can be 0.3 to 1.5 or 0.6 to 1.1 at the same time. Furthermore, it is favorable for the relevant ring geometries if H is 2 to 7 mm and preferably 2 to 6 mm or 3 to 6 mm. Furthermore, it is advantageous if A for the rings is 4 to 8 mm, preferably 4 to 6 mm. The wall thickness of preferred ring geometries is 1 to 2 mm or up to 1.5 mm.

Possible ring geometries according to the invention are therefore (A x H x I) 5 mm x 5 mm x 2 mm, or 5 mm x 2 mm x 2 mm, or 5 mm x 3 mm x 2 mm, 5 mm x 5 mm x 2.5 mm, or 5mm x 3mm x 2.5mm, or 5.5mm x 5.5mm x 2.5mm, or 5.5mm x 5.5mm x 3mm, or 5mm x 3mm x 3 mm, or 5.5 mm x 3 mm x 3.5 mm, or 6 mm x 3 mm x 4 mm, or 6 mm x 6 mm x 3 mm, or 6 mm x 6 mm x 3.5 mm, or 6.5mm x 3mm x 4.5mm, or 7mm x 3mm x 5mm, or 7mm x 7mm x 3mm, or 7mm x 3mm x 4mm, or 7mm x 7mm x 4mm.

All information in this document on specific surface areas of solids refers to the provisions according to DIN 66131 (determination of the specific surface area of solids by gas adsorption (N2) according to Brunauer-Emmert-Teller (BET)), unless expressly stated otherwise.

All information in this document on total pore volumes and pore diameter distributions on these total pore volumes refer to determinations using the method of mercury porosimetry using the Auto Pore V 9600 device (MicroActive Interactive Dara Analysis Software) from Micromeritics GmbH, D- 52072 Aachen (range: 0.1 - 61000 psi) at 23°C (evaluation with Washburn equation using a mercury contact angle of 140° and a mercury surface tension of 480 mN/m = 480 dyn/cm).

Advantageously according to the invention, precursor moldings have the lowest possible residual moisture. This is particularly the case when the intimate mixing of the various sources of the elemental constituents other than oxygen takes place wet (particularly when it takes place with the formation of an aqueous mixture M).

The residual moisture content of advantageous green compacts is preferably <10% by weight, better <8% by weight, even better <6% by weight, and best of all <4% by weight or <2% by weight (the Residual moisture determination can be carried out as described in “The Library of Technology”, Volume 229, “Thermogravimetric Material Moisture Determination”, Basics and Practical Applications, Horst Nagel, publisher moderne industrie (e.g. with the help of a Computrac MAX 5000 XL from Arizona Instruments)).

If the green compacts are based on an aqueous mixture M (so that their residual moisture content consists of water), the residual moisture determination is expediently carried out using microwaves (e.g. with the LB 456 microwave system from BERTHOLD TECHNOLOGIES).

In this procedure, the microwave radiates through the material to be examined with very low power (0.1 mW) (the latter experiences essentially no change in its temperature due to the comparatively low power). The material components are thereby polarized to different degrees. In response, the microwave loses speed and energy. The influence of water molecules is significantly greater than the influence of other components, which enables the selective determination of residual water content. This is because water molecules, due to their size and their dipole properties, are able to follow an alternating electromagnetic field in the microwave frequency range particularly well through dipole alignment. In doing so, they absorb energy and change the alternating electromagnetic field with their electrical properties. The measuring principle is based on this field weakening and field change. For example, a weak microwave field can be built up over the sensor surface of a planar sensor and the resonance frequency of the sensor system can be permanently analyzed by scanning the microwave frequency. If you now place a sample containing water over the sensor, the resonance frequency shifts and its amplitude is dampened. Both damping and resonance frequency shift increase as the amount of water increases, and therefore also as the bulk density of the material to be measured increases. However, the ratio of frequency shift and attenuation is a density-independent measure of the percentage of water and is therefore the key to moisture measurement. The ratio forms the so-called microwave moisture reading, which represents the total moisture. Since the microwave resonance method is an indirect moisture measurement method, calibration is necessary. During such a calibration measurement, material samples with a defined moisture content are measured with the sensor. The linking of the microwave moisture measurement values with the associated defined absolute material moisture levels then forms the calibration of the measuring system. The measurement accuracy is usually ± 0.1% moisture (for example, the water moisture can be determined using an online moisture measuring device PMD300PA from Sartorius).

Against this background, spray drying of a wet (e.g. aqueous) mixture M should be carried out in such a way that the resulting spray powder has the lowest possible residual moisture content.

Taking into account the point just addressed, the green compacts should be stored, if possible, with the exclusion of ambient air (which contains humidity). (The storage is preferably carried out until calcination under anhydrous inert gas or under previously dried air or in airtight containers).

The shaping/shaping and storage of finely divided, intimate dry mixture is advantageously carried out with the exclusion of ambient air (containing humidity) (e.g. under an N2 atmosphere).

The green compacts are normally calcined at temperatures (calcination temperatures) that reach at least 350°C or generally exceed them. Normally, however, the temperature of 650 ° C is not exceeded during calcination (the term calcination temperature in this document means the temperature present in the calcination material (advantageously, the calcination material has a calcination temperature that is as uniform (homogeneous) as possible); this applies in the same way to the remaining calcination conditions)). During calcination, the temperature is advantageously 600°C, preferably 570°C and often 550°C. Furthermore, in the context of the above calcination, the temperature of 380 ° C is preferably exceeded, advantageously the temperature of 400 ° C, with particular advantage the temperature of 420 ° C and most preferably the temperature of 440 ° C. The calcination process can also be divided into several sections over time.

Advantageously, prior to calcination, a thermal pretreatment is carried out at temperatures of >120°C and <350°C, preferably >150°C and <320°C, particularly preferably 170°C and <290°C. From an application point of view, such a thermal pretreatment is expediently carried out until the components contained within the mass to be thermally treated and which decompose into gaseous compounds under the conditions of the thermal treatment have been largely (preferably completely) decomposed into gaseous compounds (the time required in this regard can be, for example, 3 to 15 hours, often 4 to 10 hours or 5 to 8 hours). This is generally the case if, on the one hand, the molar amount of cations other than metal ions contained in the mass to be subsequently calcined, based on the total molar amount of cations contained, is <20 mol% (preferably <10 mol% ) and on the other hand, the molar amount of anions other than O ² ' contained in the same mass, based on the total molar amount of anions contained, is also <20 mol% (preferably <10 mol%).

Favorable temperature windows for the final calcination temperature are therefore in the temperature range 400 to 600 ° C, or preferably in the temperature range 420 to 570 ° C, or particularly preferably in the temperature range 450 to 550 ° C.

The total duration of the calcination usually lasts more than 0.5 hours, and often more than 2 hours. In most cases, calcination treatment times do not exceed 45 hours or 30 hours. The total calcination time is often less than 25 hours. In principle, a shorter calcination time is generally sufficient at higher calcination temperatures than at lower calcination temperatures. In an embodiment of the calcination that is advantageous according to the invention, 550 ° C is not exceeded and the calcination time in the temperature window > 430 ° C and < 550 ° C extends to > 4 to < 25 hours.

The entire thermal treatment (including a decomposition phase) of a precursor mass (for example a green compact) can be carried out both under an inert gas and under an oxidative atmosphere such as air (or another mixture of inert gas and molecular oxygen) and under a reducing atmosphere (for example a mixture of inert gas , NH3, CO and/or H2 or under methane). Of course you can the thermal treatment can also be carried out under vacuum. The atmosphere can also be made variable over the course of the thermal treatment.

The thermal treatment (in particular the calcination phase) preferably takes place in an oxidizing atmosphere. From an application point of view, this consists predominantly of stationary or (preferably) moving air (particularly preferably the mass to be thermally treated (the calcination material) is flowed through by an air stream). However, the oxidizing atmosphere can also consist of a standing or moving mixture of, for example, 25 vol.% N ₂ and 75 vol.% air, or 50 vol.% N ₂ and 50 vol.% air, or 75 vol.% N ₂ and 25 vol.% air (a treatment atmosphere of 100 vol.% N ₂ is also possible).

In principle, the thermal treatment (for example calcination) of the precursor mass (for example the green compacts) can be carried out in a wide variety of oven types such as heatable circulating air chambers (circulating air ovens, for example circulating air shaft ovens), tray ovens, rotary kilns, belt calciners or shaft ovens. According to the invention, the thermal treatment (for example calcination) takes place in a belt calcining device, as recommended by DE 100 46 957 A1 and WO 02/24620. A hot spot formation within the material to be treated (within the material to be calcined) is largely avoided by using fans to convey increased volume flows of calcination atmosphere through the material to be calcined through a gas-permeable conveyor belt carrying the material to be calcined (these ensure that the calcination temperature in the material to be calcined is as uniform as possible).

As part of the thermal treatment of the precursor masses (for example the green compacts) to be carried out as described, the shaping aids used can be retained both in the resulting shaped catalyst body and at least partially in gaseous form from these by thermal and/or chemical decomposition to gaseous compounds (for example CO, CO ₂ ). escape. When used catalytically, shaping aids remaining in the shaped catalyst body act essentially exclusively as diluting the active material. In principle, the thermal treatment can be carried out as described in US 2005/0131253.

Typically, the lateral compressive strengths of annular solid catalyst moldings obtainable according to the invention as described are 4 to 16 N, often 5 to 14 N or 6 to 12 N.

The specific (BET) surface area of the unsupported catalyst molding is advantageously 2 to 20 m ² /g or up to 15 m ² /g, preferably 3 to 10 m ² /g and particularly preferably 4 to 8 m ² /g. According to the invention, the associated total pore volume (mercury porosimetry) is advantageously in the range from 0.33 to 0.60 cm ³ /g, preferably in the range 0.36 to 0.54 cm ³ /g and particularly preferably in the range 0.38 to 0. 50 ^cm3 /g.

If the pore diameter in pm is plotted on the abscissa and the logarithm of the differential contribution in cm ³ /g of the respective pore diameter to the total pore volume in cm ³ /g is plotted on the ordinate, solid catalyst moldings which are particularly favorable according to the invention generally show an essentially monomodal distribution ( only has a pronounced maximum). If the contribution of pores with a pore radius <0.1 pm to the total pore volume is <0.05 cm ³ /g, particularly good overall target product selectivities result (for example in the case of a heterogeneously catalyzed partial oxidation of propene to acrolein and/or acrylic acid). In the event that the contribution of such comparatively narrow pores to the total pore volume is >0.05 cm ³ /g, an advantageous reduction in this contribution according to the invention can be achieved by increasing the calcination time and/or the calcination temperature. In addition, it proves to be advantageous for increased overall target product selectivity if the contribution of pores with a pore radius in the range of 0.1 to 1 pm to the total pore volume, based on the total pore volume, is 85 to 99 vol.%, advantageously 87 to 97 vol .-%, particularly preferably 89 to 95 vol.%.

Of course, the solid catalyst moldings can also be used diluted with inert materials to catalyze heterogeneously catalyzed partial gas phase oxidations. Suitable such inert diluent materials include element oxides fired at high temperatures and therefore comparatively poor in pores, such as aluminum oxide, silicon dioxide, thorium dioxide and zirconium dioxide. But finely divided silicon carbide or finely divided silicates such as magnesium and aluminum silicate or steatite can also be used for the aforementioned purpose. In an application-wise advantageous manner, the procedure will be, for example, that the calcined active material is ground into a finely divided powder. This is then mixed with finely divided dilution material, and the resulting mixed powder is formed into a geometric shaped body using a shaping process presented in this document (preferably by tabletting). By subsequent further calcination, the same is then transformed into the associated solid catalyst molding. Of course, the finely divided inert dilution material can also, for example, be incorporated into a wet (for example aqueous) mixture M before it has dried. Furthermore, finely divided inert diluent material can be incorporated into the finely divided dry mixture. However, such procedures are less preferred according to the invention.

In particular, solid catalyst moldings produced according to the described advantageous production processes are characterized by the fact that they have essentially no local centers of element oxides. Rather, these elements are largely part of complex, mixed oxomolybdates containing Bi, Fe and Mo. This has proven to be favorable with regard to the desired minimization of the undesirable complete combustion of organic reaction gas mixture components in the context of the relevant heterogeneously catalyzed partial oxidations.

Furthermore, for the production of solid catalysts, the procedure is expediently as in WO 2010/066645 from the perspective of the most efficient use of materials.

Shaped solid catalyst bodies according to the invention are suitable not only for catalyzing the heterogeneously catalyzed partial oxidation of propene to acrolein, but generally for catalyzing heterogeneously catalyzed partial gas phase oxidations of alkanes, alkanols, alkenes and / or alkenals containing 3 to 6 carbon atoms (partial oxidations are intended in this context). In particular, those reactions of organic compounds under the reactive action of molecular oxygen are understood to be understood in writing in which the organic compound to be partially oxidized contains at least one more chemically bound oxygen atom after the reaction has ended than before the partial oxidation was carried out). In this document, the term partial oxidation is also intended to include oxidative dehydrogenation and partial ammoxidation, i.e. partial oxidation in the presence of ammonia.

Shaped solid catalyst bodies according to the invention are particularly suitable for catalyzing the heterogeneously catalyzed partial gas phase oxidation of propene to acrolein, of iso-butene to methacrolein and for catalyzing the heterogeneously catalyzed partial gas phase ammoxidation of propene to acrylonitrile and of iso-butene to methacrylonitrile.

As already mentioned, the heterogeneously catalyzed partial gas phase oxidation of propene (iso-butene and/or tert. butanol) to acrolein (methacrolein) forms the first stage of a two-stage heterogeneously catalyzed partial gas phase oxidation of propene (iso-butene and/or tert. butanol) to acrylic acid (methacrylic acid), as described for example in WO 2006/42459.

A by-product formation of acrylic acid (methacrylic acid) associated with a heterogeneously catalyzed partial gas phase oxidation of propene (iso-butene) to acrolein (methacrolein) is therefore generally not undesirable and is usually subsumed under the desired formation of valuable products.

The aforementioned applies in particular to annular shaped solid catalyst bodies according to the invention.

The heterogeneously catalyzed partial oxidation (in particular that of propene to acrolein) can, for example, as in the documents DE 102007 004961 A1, WO 02/49757, WO 02/24620, DE 102008 040093 A1, WO 2005/030393, EP 0 575 897 A1, WO 2007/082827, WO 2005/113127, WO 2005/047224, WO 2005/042459, WO 2007/017431, DE 102008 042060 A1, WO 2008/087116, DE 102010 048405 A1, DE 102009 047291 A1, DE 102008 042064 A1, DE 10 2008 042061 A1, WO 2015/067656 and DE 10 2008 040094 A1 for similar catalysts can be carried out (in particular, the procedure can be carried out in a corresponding manner as in the exemplary embodiments of these documents).

However, the advantage of solid catalyst moldings available as described (in particular the annular) is also present when the catalyst charge to a reactor is loaded with propene, isobutene and/or tert contained in the reaction gas input mixture. Butanol (or its methyl ether) > 130 Nl/l catalyst charge • h, or > 140 Nl/l h, or > 150 Nl/l h, or > 160 Nl/l h (pre- and/or post-fills made of pure inert material When considering the load in this document, it is not considered to be part of the catalyst charge; the volume of the catalyst charge (of the fixed catalyst bed) is also the bulk volume of the catalyst charge located in the reactor). Normally, the aforementioned load on the catalyst feed will be <600 Nl/I h, often <500 Nl/I h, often <400 Nl/I h or <350 Nl/I h. Loads in the range of > 160 Nl/I h or > 180 Nl/I h to < 300 or < 250 or < 200 Nl/I h are particularly useful.

In this document, the load on a fixed catalyst bed with reaction gas input mixture is understood to mean the amount of reaction gas input mixture in standard liters (= NI; the volume in liters that the corresponding amount of reaction gas input mixture would occupy under the standard conditions of 0 ° C and 1 atm (1.01 bar)), which is fed to the fixed catalyst bed, based on the volume of its bed (bed sections made of pure inert material are not included), that is, on its bed volume, per hour (-> unit = Nl / I h). The standard volume units such as NI or Nm ³ in this document always refer to the standard conditions of 0 °C and 1 atm (1.01 bar) (unless otherwise expressly stated).

The load can also be based only on one component of the reaction gas input mixture (for example only on the organic starting compound to be partially oxidized). Then it is the volume of this component (for example the organic starting compound of the partial oxidation) that is fed to the fixed catalyst bed (the catalyst feed of the reactor), based on the volume of its bed, per hour.

Of course, unsupported catalyst bodies available according to the invention (for example ring-shaped) can be used as catalysts for the partial oxidation of propene to acrolein or of iso-butene and/or tert. Butanol (or its methyl ether) to methacrolein even when the catalyst charge is loaded with the starting compound to be partially oxidized of <130 Nl/I h, or <120 Nl/I h, or <110 Nl/I h, or <100 Nl/I h, or <90 Nl/I h be operated in an advantageous manner according to the invention. As a rule, however, this load is at values > 20 Nl/I h, or > 30 Nl/I h, or > 40 Nl/I h, or > 50 Nl/I h, or > 60 Nl/I h, or > 70 Nl/I h, or > 80 Nl/I h.

In principle, the load on the catalyst feed of a reactor (a fixed catalyst bed) with the starting compound to be partially oxidized (propene, iso-butene and/or tert. butanol (or its methyl ether)) can be adjusted using two adjusting screws: a) the load on the catalyst feed with reaction gas input mixture (the reaction gas mixture that is fed to the fixed catalyst bed), and / or b) the content of the reaction gas input mixture with the starting compound to be partially oxidized.

The (for example ring-shaped) solid catalyst moldings obtainable according to the invention are particularly suitable if, when the load on the catalyst charge with the organic compound to be partially oxidized is above 130 Nl / l h, the load is adjusted primarily via the aforementioned adjusting screw a).

As a rule, for example, the propene content (iso-butene content or tert. butanol content (or the methyl ether content)) in the reaction gas input mixture is 4 to 10% by volume, often 5 to 9% by volume, essentially independently of the load on the catalyst feed 5.5 to 8.0% by volume, or 6.0 to 7.5% by volume (in each case based on the total volume (stream) of the reaction gas input mixture flowing into the fixed catalyst bed).

The gas phase partial oxidation process of the partial oxidation (essentially independent of the load) catalyzed with the (for example ring-shaped) solid catalyst bodies according to the invention available as described is often used with an (organic) compound to be partially oxidized (for example propene): oxygen: indifferent (inert) gases (including Water vapor) volume ratio in the reaction gas input mixture of 1:(1.0 to 3.0):(5 to 25), preferably 1:(1.5 to 2.3):(10 to 20).

Indifferent gases (or inert gases) are understood to be those gases which remain chemically unchanged to the extent of at least 95 mol%, preferably at least 98 mol%, during the course of the partial oxidation when the reaction gas mixture passes through the catalyst bed once.

In the reaction gas input mixtures described above, the indifferent gas can be >20% by volume, or >30% by volume, or >40% by volume, or

> 50 vol.-%, or > 60 vol.-%, or > 70 vol.-%, or > 80 vol.-%, or too

> 90% by volume, or > 95% by volume of molecular nitrogen.

However, at higher loads on the catalyst feed of the reactor with the organic compound to be partially oxidized (for example > 150 Nl / l h), the use of inert diluent gases with increased molar heats and / or thermal conductivities such as propane, ethane, methane, pentane, butane, CO2, CO, water vapor and/or noble gases are recommended for the reaction gas input mixture (but not mandatory). In general, these inert gases and their mixtures can also be used at lower loads on the catalyst feed with the organic compound to be partially oxidized. Cycle gas can also be used as diluent gas. Cycle gas is understood to mean the residual gas that remains when essentially selectively separating the target compound from the product gas mixture of the partial oxidation. It should be taken into account that the partial oxidations to acrolein or methacrolein with the, for example ring-shaped, solid catalyst bodies available according to the invention can only be the first stage of a two-stage partial oxidation to acrylic acid or methacrylic acid as the actual target compounds, so that the recycle gas formation usually only occurs after the second stage (typical cycle gas compositions for the case of a heterogeneously catalyzed partial oxidation of propene to acrolein and / or acrylic acid are shown in DE 102 32 482 A1 in its paragraphs [0063] and [0075]). As part of such a two-stage partial oxidation, the product gas mixture from the first stage as such is generally fed to the second partial oxidation stage, optionally after cooling and/or addition of secondary oxygen (usually as air).

In the partial oxidation of propene to acrolein, using the (for example ring-shaped) unsupported catalyst bodies according to the invention available as described, a typical composition of the reaction gas input mixture measured at the reactor inlet (regardless of the selected load) can contain, for example, the following components

6 to 6.5 vol.% propene,

1 to 3.5% by volume H ₂ O, 0.8 to 1.7% by volume COx, 0.015 to 0.04% by volume acrolein,

9.4 to 12.3% by volume of oxygen and the remaining amount of 100% by volume of molecular nitrogen; or

5.6 vol.% propene,

1.4% by volume _H2O .

1.2 vol. -% COx,

10.2% by volume of oxygen and the remaining amount of 100% by volume of molecular nitrogen;

The former compositions are particularly suitable for propene loads of > 130 Nl / l h and the latter composition is particularly suitable for propene loads of < 130 Nl / l h, in particular < 100 Nl / l h (for example for starting the partial oxidation) of the fixed catalyst bed.

Alternatively, reaction gas input mixtures of the composition according to Example 1 of EP 0 990636 A1, or according to Example 2 of EP 0 990 636 A1, or according to Example 3 of EP 1 106 598 A2, or according to Example 26 of EP 1 106 598 A2, or according to Example 53 of EP 1 106 598 A2, or according to examples of WO 2021/013640 for a propene partial oxidation according to the invention to acrolein.

The inventive, for example annular, solid catalyst moldings available as described are also suitable for the processes of DE 102 46 119 A1 and DE 102 45 585 A1.

The reaction temperature for a heterogeneously catalyzed propene partial oxidation to acrolein according to the invention is often 300 to 450 ° C, or up to 400 ° C, or up to 380 ° C when using the (for example ring-shaped) unsupported catalyst bodies according to the invention available as described. A particularly preferred reaction temperature window is 305 to 345 ° C. The same applies in the case of methacrolein as the target compound. The reaction pressure for the aforementioned partial oxidations is generally 0.5 to 4 or up to 3 bar, or preferably 1.1 or 1.5 to 4 or up to 3 bar (this is what is meant in this document, unless expressly stated otherwise is, always absolute pressures).

The total load on the catalyst feed with reaction gas input mixture in the aforementioned partial oxidations according to the invention is typically 1000 to 10,000 Nl/l-h, usually 1500 to 5000 Nl/l h and often 2000 to 4000 Nl/l h.

The propene to be used in the reaction gas input mixture is primarily polymer grade propene and chemical grade propene, as described, for example, in WO 2004/007405.

Air is normally used as the oxygen source (if necessary together with cycle gas).

In the simplest case, the partial oxidation using the inventive (for example the ring-shaped) solid catalyst bodies available as described can be carried out in the simplest case, for example, in a single-zone contact tube fixed-bed reactor, such as DE 44 31 957 A1, EP 0 700 714 A1 and EP 0 700 893 A1 describe.

Typically, in the aforementioned tube bundle reactors, the contact tubes are made of ferritic steel and typically have a wall thickness of 1 to 3 mm. Their inner diameter is usually 20 to 30 mm, often 21 to 26 mm. A typical contact tube length is, for example, 3.50 m, 4.00 m or 4.50 m. The number of contact tubes accommodated in the tube bundle container is expediently at least 1000, preferably at least 5000. The number of contact tubes accommodated in the reaction container is often 15,000 to 40,000. Tube bundle reactors with a number of contact tubes above 45,000 are rather the exception. Within the container, the contact tubes are normally arranged in a homogeneous distribution, the distribution being expediently chosen so that the distance between the central inner axes of contact tubes that are closest to one another (the so-called contact tube pitch) is 35 to 45 mm (cf. EP 0 468290 B1).

However, the partial oxidation can also be carried out in a multi-zone (for example "two-zone") multi-contact tube fixed-bed reactor, as described in DE 199 10 506 A1, DE 103 13213 A1, DE 103 13208 A1 and EP 1 106 598 A2 particularly recommended in the case of increased loads on the catalyst feed of the multi-contact tube reactor with the organic compound to be partially oxidized. A typical contact tube length in the case of a two-zone multi-contact tube fixed-bed reactor is 3.50 m, 4.00 m or 4.50 m. Everything else essentially applies as described for the single-zone multi-contact tube fixed-bed reactor. A heat exchange medium is passed around the contact tubes within which the catalyst charge (the fixed catalyst bed) is located in each temperature control zone (the single-zone multi-contact tube fixed-bed reactor has only one temperature control zone) of the single-zone or multi-zone multi-contact tube fixed-bed reactor. Suitable as such are, for example, melts of salts such as potassium nitrate, potassium nitrite, sodium nitrite and/or sodium nitrate, or low-melting metals such as sodium, mercury and alloys of various metals. The flow rate of the heat exchange medium within the respective temperature control zone is usually selected so that the temperature of the heat exchange medium from the entry point into the temperature control zone to the exit point from the temperature control zone is 0 to 15 ° C, often 1 to 10 ° C, or 2 to 8 °C, or 3 to 6°C rises. The inlet temperature of the heat exchange medium, which, viewed via the respective temperature control zone, can be conducted in cocurrent or countercurrent to the reaction gas mixture, is preferably as in the documents EP 1 106 598 A2, DE 19948 523 A1, DE 19948 248 A1, DE 103 13 209 A1, EP 0 700 714 A1, DE 103 13208 A1, DE 103 13213 A1, WO 00/53557, WO 00/53558, WO 01/36364, WO 00/53557 and the other documents cited in these documents as prior art are recommended chosen. Within the temperature control zone, the heat exchange medium is preferably guided in a meandering manner. The difference between the highest and the lowest temperature of the heat exchange medium located within a temperature control zone should, when viewed over that longitudinal section of the temperature control zone in which there is a catalytically active (not a pure inert bed) section of the fixed catalyst bed, advantageously be > 0 ° C and < 5 °C (preferably this difference is small). As a rule, the multi-contact tube fixed bed reactor also has thermal tubes for determining the temperature of the reaction gas in the catalyst bed (thermal tubes and reaction tubes are charged with the same fixed bed). The inner diameter of the thermal tubes and the diameter of the receiving sleeve (thermal sleeve) for the thermocouple, which is centered inside them and runs parallel to the longitudinal axis of the thermal tube, is expediently chosen so that the ratio of the volume developing reaction heat to the heat-dissipating surface is the same for thermal tubes and working tubes or only slightly different from each other.

The pressure loss should be the same for working tubes and thermal tubes, based on the same GHSV (= strength of the volume flow of the reaction gas mixture entering the tube divided by the bulk volume of the fixed catalyst bed in the tube). Pressure loss compensation in the thermal tube can be achieved, for example, by adding split catalyst to the solid catalyst moldings. This compensation is expediently carried out homogeneously over the entire length of the thermal tube. Furthermore, the filling of thermal tubes can be designed as described in EP 0 873 783 A1.

To prepare the catalyst charge in the contact tubes, as already mentioned, only (for example ring-shaped) solid catalyst moldings available as described or, for example, largely homogeneous mixtures of (for example ring-shaped) solid catalyst moldings available as described and which do not contain any active material, can be used with respect to the heterogeneously catalyzed partial gas phase oxidation Essentially inert shaped bodies are used. Possible materials for such inert molded bodies are, for example, porous or non-porous aluminum oxides, silicon dioxide, zirconium dioxide, silicon carbide, silicates such as magnesium or aluminum silicate and/or steatite (for example type C220 from CeramTec, DE).

The geometry of such inert dilution moldings is arbitrary. This means that they can be, for example, spheres, polygons, solid cylinders or, for example in the case of annular shaped catalyst bodies, rings. The inert dilution moldings chosen are those whose geometry corresponds to that of the catalyst moldings to be diluted with them. However, the geometry of the shaped catalyst body can also be changed along the catalyst charge or shaped catalyst bodies of different geometries can be used in a largely homogeneous mixture. In a less preferred procedure, the active mass of the shaped catalyst body can also be changed along the catalyst charge.

In general, the catalyst feed is advantageously designed in such a way that the volume-specific activity (that is, the activity normalized to the unit of volume) either remains constant or increases (continuously, abruptly or stepwise) in the direction of flow of the reaction gas mixture.

A reduction in the volume-specific activity can be achieved in a simple manner, for example, by using a basic amount of uniform according to the invention produced (for example ring-shaped) solid catalyst moldings are homogeneously diluted with inert diluent moldings. The higher the proportion of diluent shaped bodies selected, the lower the active material or catalyst activity contained in a certain volume of the feed. However, a reduction can also be achieved by changing the geometry of the shaped solid catalyst bodies obtainable according to the invention in such a way that the amount of active material contained in the unit of the reaction tube internal volume becomes smaller.

For the heterogeneously catalyzed gas phase partial oxidations with (for example ring-shaped) unsupported shaped catalyst bodies available as described, the catalyst charge is preferably either designed uniformly over the entire length with only one type of unsupported shaped catalyst body or structured as follows. At the reactor inlet, over a length of 10 to 60%, preferably 10 to 50%, particularly preferably 20 to 40% and very particularly preferably 25 to 35% (that is, for example over a length of 0.70 to 1.50 m, preferably 0.90 to 1.20 m), in each case the total length of the catalyst charge, a substantially homogeneous mixture of (for example annular) solid catalyst moldings and inert dilution moldings (both preferably having essentially the same geometry) is placed, the weight proportion of the dilution moldings ( the mass densities of catalyst moldings and of diluent moldings generally differ only slightly) normally 5 to 40% by weight, or 10 to 40% by weight, or 20 to 40% by weight, or 25 to 35% by weight % amounts. Following this first loading section, there is then advantageously up to the end of the length of the catalyst loading (that is, for example, over a length of 1.00 to 3.00 m or from 1.00 to 2.70 m, preferably 1.40 to 3.00 m, or 2.00 to 3.00 m) either a bed of the same (for example ring-shaped) solid catalyst moldings available as described that is only diluted to a lesser extent (than in the first section), or, very particularly preferably, a sole (undiluted) Filling the same (for example ring-shaped) solid catalyst molding that was also used in the first section. Of course, a constant dilution can also be selected across the entire feed. Also, in the first section, only a (for example annular) solid catalyst molding with a low active mass density based on its space requirement can be charged and in the second section with a (for example annular) solid catalyst molding available according to the invention with a high active mass density based on its space requirement (for example 6, 5mm x 3mm x 4.5mm [Outer Diameter x Height x Inner Diameter] in the first section, and 5 x 2 x 2mm [A x H x I] in the second section).

In the direction of flow of the reaction gas mixture upstream of the actual fixed catalyst bed, a bed of inert shaped bodies can be applied, which has the purpose, for example, of increasing the inlet temperature of the reaction gas mixture to the temperature of the heat exchange medium.

Furthermore, according to the teachings of the prior art (for example WO 2012/049246), the catalyst feed (in particular the fresh one) of the reactor and the process conditions of the catalyzed partial oxidation in the case of the heterogeneously catalyzed partial oxidation of propene to acrolein (or in the case of a heterogeneously catalyzed partial oxidation for the production of methacrolein) is preferably chosen (designed) so that in the partial oxidation operation at no point in the fixed catalyst bed is the difference between the temperature of this point of the fixed catalyst bed and the temperature of the heat exchange medium at this point > 120 ° C. Advantageously, this temperature difference is positive at any point but <100°C (in particular 40 to 100°C), particularly advantageously <90°C (in particular 50 to 90°C). In principle, this (positive) temperature difference can also be <50°C or <40°C. Furthermore, the embodiment is preferably such that this temperature difference increases by > 0°C but <+9°C, better <+7°C, preferably <+5°C, particularly preferably <+3°C increases (see also EP 1 106 598 A1).

Furthermore, a heterogeneously catalyzed partial oxidation for the production of acrolein (from propene) or methacrolein (from the C4 precursor compounds mentioned in the present document) can advantageously be carried out with annular solid catalyst moldings produced according to the invention in complete accordance with the statements in WO 2015/067656 .

Overall, in a partial oxidation carried out with the (for example ring-shaped) solid catalyst bodies available as catalysts as catalysts for the production of acrolein or methacrolein, the catalyst charge, the reaction gas starting mixture, the load and the reaction temperature are generally selected so that when the reaction gas mixture passes through the catalyst charge once a conversion of the organic compound to be partially oxidized (propene, iso-butene, tert-butanol or its methyl ether) of at least 90 mol%, or at least 92 mol%, preferably of at least 93 mol% or at least 94 mol- % or at least 95 mol% or at least 97 mol%, but normally <99 mol% results. The selectivity of the valuable products (sum of acrolein and acrylic acid or sum of methacrolein and methacrylic acid) will regularly be > 80 mol%, or > 85 mol% or > 90 mol%.

Finally, it should be noted that solid catalyst moldings according to the invention that are available as described also have an advantageous fracture behavior when filling the reactor.

The commissioning of a fresh catalyst feed (fixed catalyst bed) containing (for example ring-shaped) solid catalyst bodies available according to the invention can, for. B. as described in DE 103 37 788 A1 or as described in DE 10 2009 047291 A1.

The formation of unsupported catalyst moldings obtainable according to the invention can be accelerated by carrying it out with essentially constant conversion under increased loading of the catalyst feed with reaction gas input mixture.

Furthermore, solid catalysts available according to the invention are generally used to catalyze the gas phase partial (amm) oxidation of an alkanol, alkanal, aikene, alkane and alkenal containing 3 to 6 (that is, 3, 4, 5 or 6) carbon atoms to form, for example, olefinically unsaturated aldehydes and/or carboxylic acids and the corresponding nitriles, and suitable for gas phase catalytic oxidative dehydrogenations of the aforementioned organic compounds containing 3, 4, 5 or 6 carbon atoms.

The large-scale production of solid catalyst moldings according to the invention is expediently carried out analogously to that described in DE 10 2008 040093 A1 and DE 10 2008 040094 A1 (particularly advantageous as in the exemplary embodiments of these documents).

The present application therefore includes in particular the following embodiments according to the invention:

The present invention therefore includes in particular the following embodiments according to the invention:

1. A process for producing unsupported shaped catalyst bodies for the gas phase oxidation of an aikene and/or an alcohol to form an α,ß-unsaturated aldehyde and/or an α,ß-unsaturated carboxylic acid, wherein the unsupported shaped catalyst bodies comprise at least the elements molybdenum, bismuth, iron and cobalt, where a) an aqueous solution or aqueous suspension is produced from at least one source of the elemental constituents molybdenum, bismuth, iron, cobalt and optionally at least one source of the elemental constituent nickel, b) by drying the aqueous solution or aqueous suspension obtained in a) and optionally comminution, a powder P is produced, c) that powder P obtained in b), optionally with the addition of one or more auxiliaries and after uniform mixing and optional compaction, is compacted into precursor moldings with a cylindrical structure, and d) those obtained in c). Precursor moldings are thermally treated to form the solid catalyst moldings, characterized in that the pressure during compression in c) is selected so that the density of the precursor moldings is from 1.70 to 2.30 g / cm ³ , the density of the precursor moldings being The quotient of the mass and the geometric volume is, and the weight loss during the thermal treatment in d) is from 25 to 40% by weight.

2. Method according to embodiment 1, characterized in that the pressure during compression in c) is selected so that the density of the precursor moldings is from 1.72 to 2.28 g/cm ³ .

3. Method according to embodiment 1 or 2, characterized in that the pressure during compression in c) is selected so that the density of the precursor moldings is from 1.74 to 2.26 g/cm ³ .

4. Method according to one of embodiments 1 to 3, characterized in that the pressure during compression in c) is selected so that the density of the precursor moldings is from 1.76 to 2.24 g/cm ³ .

5. Method according to one of embodiments 1 to 4, characterized in that the pressure during compression in c) is selected such that the density of the precursor moldings is from 1.78 to 2.22 g/cm ³ .

6. Method according to one of embodiments 1 to 5, characterized in that the pressure during compression in c) is selected so that the density of the precursor moldings is from 1.80 to 2.20 g/cm ³ .

7. Process according to one of embodiments 1 to 6, characterized in that the weight loss during the thermal treatment in d) is from 26 to 39% by weight.

8. Process according to one of embodiments 1 to 7, characterized in that the weight loss during the thermal treatment in d) is from 27 to 38% by weight.

9. Process according to one of embodiments 1 to 8, characterized in that the weight loss during the thermal treatment in d) is from 28 to 38% by weight.

10. Process according to one of embodiments 1 to 9, characterized in that the weight loss during the thermal treatment in d) is from 29 to 37% by weight.

11. Process according to one of embodiments 1 to 10, characterized in that the weight loss during the thermal treatment in d) is from 30 to 35% by weight. 12. The method according to one of embodiments 1 to 11, characterized in that the cylindrical structure is i) a cylindrical body with a circular through-hole in the center in the longitudinal direction or ii) a cylindrical body notched evenly in the longitudinal direction 3 times with three evenly arranged in the longitudinal direction circular continuous openings.

13. Method according to one of embodiments 1 to 12, characterized in that the cylindrical structure is a hollow cylinder.

14. Process according to one of embodiments 1 to 13, characterized in that the molybdenum content of the unsupported catalyst moldings, calculated as moss, is from 45 to 75% by weight.

15. Process according to one of embodiments 1 to 14, characterized in that the molybdenum content of the unsupported catalyst moldings, calculated as moss, is from 50 to 70% by weight.

16. Process according to one of embodiments 1 to 15, characterized in that the molybdenum content of the unsupported catalyst moldings, calculated as moss, is from 55 to 65% by weight.

17. Process according to one of embodiments 1 to 16, characterized in that the bismuth content of the unsupported shaped catalyst bodies, calculated as Bi2Ö3, is from 1 to 20% by weight.

18. Process according to one of embodiments 1 to 17, characterized in that the bismuth content of the unsupported shaped catalyst bodies, calculated as Bi2Ö3, is from 2 to 15% by weight.

19. Process according to one of embodiments 1 to 18, characterized in that the bismuth content of the unsupported shaped catalyst bodies, calculated as Bi ₂ Ö3, is from 3 to 10% by weight.

20. Process according to one of embodiments 1 to 19, characterized in that the iron content of the solid catalyst moldings, calculated as Fe2Ö3, is from 2 to 12% by weight.

21. Process according to one of embodiments 1 to 20, characterized in that the iron content of the solid catalyst shaped bodies, calculated as Fe2Ö3, is from 3 to 11% by weight.

22. Process according to one of embodiments 1 to 21, characterized in that the iron content of the solid catalyst shaped bodies, calculated as Fe2Ö3, is from 4 to 10% by weight.

23. Process according to one of embodiments 1 to 22, characterized in that the content of cobalt and nickel in the solid catalyst moldings, calculated as Co and Ni, is from 9 to 30% by weight. 24. Process according to one of embodiments 1 to 23, characterized in that the content of cobalt and nickel in the solid catalyst moldings, calculated as CoO and NiO, is a total of 12 to 27% by weight.

25. Process according to one of embodiments 1 to 24, characterized in that the content of cobalt and nickel in the solid catalyst moldings, calculated as CoO and NiO, is a total of 15 to 24% by weight.

26. Process according to one of embodiments 1 to 25, characterized in that the solid catalyst moldings additionally contain the elements potassium and/or silicon.

27. Unsupported shaped catalyst body with a cylindrical structure for the gas phase oxidation of an Aikens and/or an alcohol to an α,ß-unsaturated aldehyde and/or an α,ß-unsaturated carboxylic acid, obtainable by a process of embodiments 1 to 26, wherein the unsupported shaped catalyst body at least Elements include molybdenum, bismuth, iron and cobalt, the density of the solid catalyst shaped body being from 1.20 to 1.70 g/cm ³ , the density of the solid catalyst shaped body being the quotient of the mass and the geometric volume, the total pore volume of the solid catalyst shaped body being of 0.33 to 0.60 cm ³ /g and the pore volume of the solid catalyst shaped body is in the range of 0.1 to 1 pm from 85 to 99% of the total pore volume, the total pore volume and the pore volume being in the range of 0.1 to 1 pm is determined by mercury porosimetry.

28. Unsupported shaped catalyst body according to embodiment 27, wherein the density of the unsupported shaped catalyst body is from 1.22 to 1.68 g/cm ³ .

29. Unsupported shaped catalyst body according to embodiment 27 or 28, wherein the density of the unsupported shaped catalyst body is from 1.24 to 1.66 g/cm ³ .

30. Unsupported shaped catalyst body according to one of embodiments 27 to 29, wherein the density of the unsupported shaped catalyst body is from 1.26 to 1.64 g/cm ³ .

31. Unsupported shaped catalyst body according to one of embodiments 27 to 30, wherein the density of the unsupported shaped catalyst body is from 1.28 to 1.62 g/cm ³ .

32. Unsupported shaped catalyst body according to one of embodiments 27 to 31, wherein the density of the unsupported shaped catalyst body is from 1.30 to 1.60 g/cm ³ .

33. Unsupported shaped catalyst body according to one of embodiments 27 to 32, wherein the total pore volume of the unsupported shaped catalyst body is from 0.34 to 0.58 cm ³ /g.

34. Unsupported shaped catalyst body according to one of embodiments 27 to 33, wherein the total pore volume of the unsupported shaped catalyst body is from 0.35 to 0.56 cm ³ /g.

35. Unsupported shaped catalyst body according to one of embodiments 27 to 34, wherein the total pore volume of the unsupported shaped catalyst body is from 0.36 to 0.54 cm ³ /g.

36. Unsupported shaped catalyst body according to one of embodiments 27 to 35, wherein the total pore volume of the unsupported shaped catalyst body is from 0.37 to 0.52 cm ³ /g.

37. Unsupported shaped catalyst body according to one of embodiments 27 to 36, wherein the total pore volume of the unsupported shaped catalyst body is from 0.38 to 0.50 cm ³ /g. 38. Unsupported shaped catalyst body according to one of embodiments 27 to 37, wherein the pore volume of the unsupported shaped catalyst body is in the range from 0.1 to 1 μm from 86 to 98% of the total pore volume.

39. Unsupported shaped catalyst body according to one of embodiments 27 to 38, wherein the pore volume of the unsupported shaped catalyst body is in the range from 0.1 to 1 μm from 87 to 97% of the total pore volume.

40. Unsupported shaped catalyst body according to one of embodiments 27 to 39, wherein the pore volume of the unsupported shaped catalyst body is in the range from 0.1 to 1 μm from 88 to 96% of the total pore volume.

41. Unsupported shaped catalyst body according to one of embodiments 27 to 40, wherein the pore volume of the unsupported shaped catalyst body is in the range from 0.1 to 1 μm of 89 to 95% of the total pore volume.

42. Solid catalyst molding according to one of embodiments 27 to 41, wherein the cylindrical structure is i) a cylindrical body with a circular through-hole in the center in the longitudinal direction or ii) a cylindrical body which is evenly notched three times in the longitudinal direction and has three circular through-holes which are evenly arranged in the longitudinal direction is.

43. Solid catalyst molding according to embodiment 42, wherein the shortest distance between the outer wall of the cylindrical body and the next through opening is from 0.75 to 2.5 mm.

44. Solid catalyst molding according to embodiment 42 or 43, wherein the shortest distance between the outer wall of the cylindrical body and the next through opening is from 0.8 to 2.0 mm.

45. Molded solid catalyst body according to one of embodiments 42 to 44, wherein the shortest distance between the outer wall of the cylindrical body and the next through opening is from 1.0 to 1.8 mm.

46. Molded solid catalyst body according to one of embodiments 42 to 45, wherein the shortest distance between the outer wall of the cylindrical body and the next through opening is from 1.2 to 1.7 mm.

47. Molded solid catalyst body according to one of embodiments 42 to 46, wherein the shortest distance between the outer wall of the cylindrical body and the next through opening is from 1.3 to 1.6 mm.

48. Solid catalyst molding according to one of embodiments 27 to 42, wherein the cylindrical structure is a hollow cylinder.

49. Solid catalyst molding according to embodiment 48, wherein the wall thickness of the hollow cylinder is from 0.75 to 2.5 mm.

50. Solid catalyst molding according to embodiment 48 or 49, wherein the wall thickness of the hollow cylinder is from 0.8 to 2.0 mm. 51. Solid catalyst molding according to one of embodiments 48 to 50, wherein the wall thickness of the hollow cylinder is from 1.0 to 1.8 mm.

52. Solid catalyst molding according to one of embodiments 48 to 51, wherein the wall thickness of the hollow cylinder is from 1.2 to 1.7 mm.

53. Solid catalyst molding according to one of embodiments 48 to 52, wherein the wall thickness of the hollow cylinder is from 1.3 to 1.6 mm.

54. Unsupported shaped catalyst body according to one of embodiments 27 to 53, wherein the unsupported shaped catalyst body is a multi-element oxide of the general formula I

Moi ₂ BiaFe _b COcNidXeY _f Z _g On (I) with

X = K, Cs and/or Rb

Y = Ca, Sr, Ba, Li, Na, Cr, W, Mn, Cu, Zn, Ga, P, B, As, Sn, Sb, Te, Nb, Ta, Pb, Ce and/or La

Z = Si, Al, Ti, Zr and/or Mg a = 0.2 to 2 b = 1 to 4 c = 3 to 9 d = 0 to 4 c + d = 4 to 9.5 e = 0.01 to 0.5 f = 0 to 10 g = 0 to 10 n = a number determined by the valence and frequency of the elements other than oxygen in general formula I.

55. Process for producing an α,β-unsaturated aldehyde and/or an α,β-unsaturated carboxylic acid, wherein an alkene and/or an alcohol with molecular oxygen over a fixed catalyst bed which is a bed of unsupported shaped catalyst bodies according to one of embodiments 27 to 54 includes, is guided.

56. Method according to embodiment 55, characterized in that the propene is used as an alkene.

57. Fixed bed reactor containing a bed of solid catalyst moldings according to one of embodiments 27 to 55.

Examples

Production of the solid catalyst moldings K1 to K10:

example 1

Production of the solid catalyst precursor shaped body K1, the active multimetal oxide having the stoichiometry Mo^CoyFesBio.eSii.ßKo.osOx. The stirring containers used were each filled in the presence of ambient air. During stirring/mixing, they were sealed airtight with a lid that had a pressure relief valve to the atmosphere (1.01 bar). a) Preparation of an aqueous solution B

430 kg of deionized water were placed in a temperature-controlled cylindrical stirring container (1.75 m ³ internal volume, 1.3 m diameter) made of stainless steel (EN 1.4541) equipped with a stirrer and heated to 60 ° C while stirring (70 rpm).

Then, with constant stirring and maintaining the temperature of 60 ° C, 0.61 kg of an aqueous potassium hydroxide solution (47.5% by weight of KOH), which had a temperature of 20 ° C, was added in one minute. While maintaining the 60 ° C, 136.2 kg of fine-grained ammonium heptamolybdate tetrahydrate (54.3% by weight Mo, supplier: NIPPON INORGANIC COLOR & CHEMICAL CO., LTD., 3-14-1 Funado ltabashi -ku Tokyo 174-0041 Japan), which had a temperature of 25 ° C, was stirred in portions and the resulting aqueous solution (it was slightly cloudy due to the slightest insoluble isopolymolybdate impurities) was stirred at 60 ° C for 60 minutes (70 U/ minutes). b) Preparation of an aqueous solution A

212 kg of an aqueous nitric acid cobalt (II) nitrate solution (12.5% by weight) were placed in a temperature-controlled cylindrical stirring container (1.75 m ³ internal volume, 1.3 m diameter) made of stainless steel (EN 1.4541) equipped with a stirrer. Co, 27% by weight nitrate, produced by dissolving cobalt metal from MFT Metals % Ferro-Alloys Trading GmbH, D-41474 Viersen, purity > 99.6% by weight Co, < 0.3% by weight Ni, <100 mg/kg Fe, <50 mg/kg Cu in aqueous nitric acid) and heated to 60° C. with stirring (70 rpm).

With continued stirring (70 rpm) and continued heating to 60 ° C, 78 kg of a 60 ° C warm iron (III) nitrate nonahydrate melt (13.8 wt .-% Fe, <0.4 wt .-% alkali metals, <0.01% by weight chloride, <0.02% by weight sulfate, from Dr. Paul Lohmann GmbH, D-81857 Emmerthal) and stirred for 30 minutes at 60 ° C (70 rpm).

72.6 kg of a 60° C. warm, aqueous, nitric acid bismuth nitrate solution (11.1% by weight Bi, 13% by weight) were added to the resulting aqueous solution while maintaining the 60 ° C and continued stirring (70 rpm). Nitrate, produced by dissolving bismuth metal from Sidech S.A., BE-1495 Tilly, purity > 99.997 wt.% Bi, <7 mg/kg Pb, <5 mg/kg each Ni, Ag, Fe, <3 mg each /kg Cu, Sb and <1 mg/kg each of Cd, Zn in aqueous nitric acid) and then stirred at 60 ° C for a further 30 minutes (70 rpm). c) Mixing the aqueous solution A with the aqueous solution B

The 60 ° C warm aqueous solution A was continuously metered into the intensively stirred (70 rpm) 60 ° C warm aqueous solution B within 15 minutes. The resulting aqueous suspension was stirred at 60 ° C for a further 15 minutes. d) Addition of a silica sol to obtain an aqueous mixture M

After stirring had ended, 12.6 kg of silica gel from Grace GmbH & KG, In der Hollerecke 1, D-67545 Worms of the type LUDOX TM50 (47.5 wt.) heated to 60° C. were immediately added to the aqueous mixture obtained in c). % SiÜ2) added. e) Spray drying of the aqueous mixture M

The spray drying of the aqueous mixture M took place immediately after its production. The aqueous mixture (suspension) M, which was further stirred (also during spray drying) at 60 ° C using the stirrer (40 rpm), was removed in a spray tower (type S-50-N/R from Niro A/S). Stainless steel 1.4541) with a centrifugal atomizer type FS-15 and an atomizer wheel type AM8-150 spray-dried in hot air co-current (gas inlet temperature: 350 ± 10°C, gas outlet temperature: 140 ± 5°C, gas flow rate: 2200 ± 100 Nm ³ /h, speed of the atomizer wheel: 20000 rpm).

The spray powder obtained was temporarily stored (10 calendar days) in airtight containers (200 l or 1000 l internal volume, 25 ° C, atmospheric pressure) until further processing; shorter or longer interim storage (up to 30 calendar days) had no influence on the resulting results ). The loss on ignition of the spray powder obtained (annealing for 3 hours at 600 ° C (powder temperature) under standing air in excess) was 31 ± 2% by weight of its initial weight. The spray powder had a D50 of 35 ± 10 pm (D50 means that 50% of the particles are smaller than the specified value) at a dispersion pressure of 2.0 bar absolute. f) Production of ring-like precursor shaped bodies

100 kg of spray powder and 1 kg of graphite (grade 3160 from Asbury Graphite Mills Inc., New Jersey 08802) were then placed in an inclined mixer (type VIL, filling volume: 200 l, Aachener Misch- und Kneadingmaschinenfabrik) with mixing and cutting blades (Speed speed of mixing blade: 39 rpm, speed of cutting blade: 3000 rpm) and premixed for 5 minutes.

The resulting mixture was then placed in a compact type K200/100 from Hosokawa Bepex GmbH with concave, fluted smooth rollers (roll diameter 100 mm, roller length 200 mm, gap width: 2.8 mm, roller speed: 5 rpm, press force setpoint: 80 kN , length-specific pressing force setpoint 8 kN / cm). A compact with a particle size mostly between 200 pm and 1.5 mm was isolated using integrated vibrating screens from Allgaier (screen width oversize: 1.5 mm, screen width undersize: 200 pm) with ball sieve aids (diameter 22 mm).

For tabletting, a further 2.5% by weight of the graphite (grade 3160 from Asbury Graphite Mills Inc., New Jersey 08802) was added to the compact in a turbulent mixer from Drais within 2 minutes.

The granules produced were then formed using a Korsch XT-600 rotary machine (with 65 EURO B dies) under a dry air atmosphere to form ring-like precursor moldings with the geometry A x H x I = 5 mm x 5 mm x 2 mm with a non-curved (i.e. planar) The end face of a mass (M _v ) of 188 mg was compacted (tableted). The applied pre-compression force (pressing force) was 0.7 kN, the applied main compressive force (pressing force) was 2.7 kN. The rotor speed was 40 rpm. The lateral compressive strength (SDF _V ) of the resulting ring-like precursor moldings was 23 N. g) Thermal pretreatment and calcination of the ring-like precursor moldings produced in f).

The formed rings were placed on the belt of a belt calciner (as in the

WO 2002/024620) with eight chambers (chamber width 100 cm, chamber length 150 cm). Chambers 1 to 8 each had a fan to generate air circulation and were thermostated at 150 ° C, 190 ° C, 220 ° C, 265 ° C, 380 ° C, 430 ° C, 520 ° C and 520 ° C. Heated air was metered into each chamber. The amount of supply air to chambers 1 to 8 were 90 Nm ³ /h, 130 Nm ³ /h, 255 Nm ³ /h, 90 Nm ³ /h, 150 Nm ³ /h, 90 Nm ³ /h, 90 Nm, respectively ³ /h and 140 Nm ³ /h. Exhaust air was removed from each chamber using a fan. The amount of exhaust air to chambers 1 to 8 were 130 Nm ³ /h, 290 Nm ³ /h, 305 Nm ³ /h, 144 Nm ³ /h, 135 Nm ³ /h, 80 Nm ³ /h, 80 Nm, respectively ³ /h and 130 Nm ³ /h.

The filling height of chambers 1 to 4 was 40 mm. The filling height of chambers 5 to 8 was 75 mm. Within the chambers, the temporal and spatial deviation of the temperature from the target value was always <10°C.

The belt speeds were such that the residence time in the first four chambers was 105 minutes each and 270 minutes in the fifth to eighth chambers.

In this way, 2.6 t of solid catalyst moldings K1 were produced.

Example 2 (not according to the invention)

Production of the solid catalyst molding K2, the active multimetal oxide having the stoichiometry Mo^CoyFesBio.eSii.ßKo.osOx.

The production of the solid catalyst moldings K2 was carried out in the same way as the production of the solid catalyst molding K1 with a modification in f).

The precursor moldings were compressed (tableted) to a mass (M _v ) of 220 mg. The applied pre-compression force (pressing force) was 1.3 kN, the applied main compressive force (pressing force) was 6.8 kN. The lateral compressive strength (SDF _V ) of the resulting ring-like precursor moldings was 48 N.

Example 3

Production of the solid catalyst molding K3, the active multimetal oxide having the stoichiometry Mo^CoyFesBio.eSii.ßKo.osOx.

The production of the solid catalyst moldings K3 was carried out in the same way as the production of the solid catalyst molding K1 with modifications in f) and g).

The granules produced were in f) using a Kilian E150+ rotary machine (with 21 EURO D matrices) under a dry air atmosphere to form ring-like precursor molds with the geometry A x H x I = 5 mm x 3 mm x 2 mm with a non-curved (i.e. planar) shape ) End face of a mass (M _v ) of 90 mg is compacted (tableted). The rotor speed was 25 rpm. The lateral compressive strength (SDFv) of the resulting ring-like precursor moldings was 6 N.

1000 g of the precursor moldings produced in f) were evenly divided into four grids arranged next to one another, each with a base area of 150 mm x 150 mm (filling height: 15 mm) in an air previously dried with 4500 Nl / h (which has an inlet temperature of 140 ° C (the circulating air oven was in an environment at 25 ° C). The temperature in the circulating air shaft furnace was then varied as follows while maintaining the air flow (including its inlet temperature) (the temperature information means the temperature in the respective applied bulk material; this was determined using four thermocouples, each of which is located in the geometric center of the four grids in the center of the the bulk material placed on the respective grid; one of the thermocouples provided the actual value for temperature control of the circulating air shaft furnace ready; the other thermocouples confirmed that the temperatures were identical within the interval ± 0.1 °C). The temperature increases were essentially linear over time. It was heated from 25°C to 130°C within 72 minutes. The 130°C was held for 72 minutes before the temperature was increased to 190°C over 36 minutes. The 190°C was held for 72 minutes before the temperature was increased to 220°C over 36 minutes. The 220°C was held for 72 minutes before the temperature was increased to 265°C over 36 minutes. The 265°C was held for 72 minutes before the temperature was increased to 380°C over 93 minutes. The 380°C was held for 187 minutes before the temperature was increased to 430°C over 93 minutes. The 430 ° C was held for 187 minutes before increasing to the final calcination temperature of 500 ° C within 93 minutes. This was maintained for 463 minutes. The mixture was then cooled to 25°C within 12 hours. For this purpose, both the heating of the circulating air shaft furnace and the air flow preheating were switched off (however, the air flow of 4500 Nl/h as such was maintained; the inlet temperature of the air flow was then 25 °C).

Example 4 (not according to the invention)

Production of the solid catalyst shaped body K4, the active multimetal oxide having the stoichiometry Mo^CoyFesBio.eSii.ßKo.osOx.

The production of the solid catalyst moldings K4 was carried out in the same way as the production of the solid catalyst moldings K3 with a modification in f).

The precursor moldings were compressed (tableted) to a mass (M _v ) of 122 mg. The lateral compressive strength (SDFv) of the resulting ring-like precursor moldings was 22 N.

Example 5

Production of the solid catalyst molding K5, the active multimetal oxide having the stoichiometry Moi2Co8.3Fe2.iBio,6Sii,6Ko,o80 _x .

The stirring containers used were each filled in the presence of ambient air. When stirring/mixing, they were sealed airtight with a lid that had a pressure relief valve to the atmosphere (1.01 bar). a) Preparation of an aqueous solution B

654 kg of deionized water were placed in a temperature-controlled cylindrical stirring container (1.75 m ³ internal volume, 1.3 m diameter) made of stainless steel (EN 1.4541) equipped with a stirrer and heated to 60 ° C while stirring (70 rpm).

Then, with constant stirring and maintaining the temperature of 60 ° C, 0.36 kg of an aqueous potassium hydroxide solution (47.5% by weight of KOH), which had a temperature of 20 ° C, was added in one minute. While maintaining the 60 ° C, 80.4 kg of fine-grained ammonium heptamolybdate tetrahydrate (54.3% by weight Mo, supplier: NIPPON INORGANIC COLOR & CHEMICAL CO., LTD., 3-14-1 Funado ltabashi -ku Tokyo 174-0041 Japan), which had a temperature of 25 ° C, stirred in portions and the resulting aqueous solution (it was slightly cloudy due to the slightest insoluble isopolymolybdate impurities) was stirred at 60 ° C for 60 minutes (70 nights / minutes). b) Preparation of an aqueous solution A

148.4 kg of an aqueous nitric ^acid cobalt (II) nitrate solution (12.5 wt. -% Co, 27% by weight nitrate, produced by dissolving cobalt metal from MFT Metals % Ferro-Alloys Trading GmbH, D- 41474 Viersen, purity > 99.6% by weight Co, < 0.3% by weight. -% Ni, <100 mg/kg Fe, <50 mg/kg Cu in aqueous nitric acid) and heated to 60° C. with stirring (70 rpm).

With continued stirring (70 rpm) and continued heating to 60 ° C, 32.3 kg of a 60 ° C warm iron (III) nitrate nonahydrate melt (13.8% by weight Fe, <0, 4% by weight alkali metals, <0.01% by weight chloride, <0.02% by weight sulfate, from Dr. Paul Lohmann GmbH, D-81857 Emmerthal) and stirred at 60 ° C for 30 minutes (70 rpm).

42.8 kg of a 60° C. warm, aqueous, nitric acid bismuth nitrate solution (11.1% by weight Bi, 13% by weight nitrate) were added to the resulting aqueous solution while maintaining the 60 ° C and continued stirring (70 rpm). (NO ^3- ), produced by dissolving bismuth metal from Sidech SA, BE-1495 Tilly, purity > 99.997 wt.% Bi, <7 mg/kg Pb, <5 mg/kg each Ni, Ag, Fe, <3 mg/kg each of Cu, Sb and <1 mg/kg each of Cd, Zn in aqueous nitric acid) and then stirred for a further 30 minutes at 60° C. (70 rpm). c) Mixing the aqueous solution A with the aqueous solution B

After stirring had ended, 7.4 kg of silica gel from Grace GmbH & KG, In der Hollerecke 1, D-67545 Worms of the type LUDOX TM50 (47.5 wt.) heated to 60° C. were immediately added to the aqueous mixture obtained in c). % SiÜ2) added. e) Spray drying of the aqueous mixture M

The spray drying of the aqueous mixture M took place immediately after its production. The aqueous mixture (suspension) M, which was further stirred (also during spray drying) at 60 ° C using the stirrer (40 rpm), was removed in a spray tower (type S-50-N/R from Niro A/S). Stainless steel 1.4541) spray-dried in hot air direct current (gas inlet temperature: 350 ± 10 C, gas outlet temperature: 140 ± 5 ° C, gas flow rate: 2200 ± 100 Nm ³ /h, speed of the atomizer wheel: 20,000 rpm).

100 kg of spray powder and 1 kg of graphite (grade 3160 from Asbury Graphite Mills Inc., New Jersey 08802) were then placed in an inclined mixer (type VIL, filling volume: 200 l, Aachen mixing and kneading machine factory) with mixing and cutting blades (mixing blade speed: 39 ll/min, cutting blade speed: 3000 ll/min) and pre-mixed for 5 minutes.

The resulting mixture was then placed in a compact type K200/100 from Hosokawa Bepex GmbH) with concave, fluted smooth rollers (roll diameter 100 mm, roller length 200 mm, gap width: 2.8 mm, roller speed: 5 ll/min, press force setpoint: 80 kN, length-specific pressing force setpoint 8 kN / cm). A compact with a particle size mostly between 200 pm and 1.5 mm was isolated using integrated vibrating screens from Allgaier (screen width oversize: 1.5 mm, screen width undersize: 200 pm) with ball sieve aids (diameter 22 mm).

The granules produced as described were then formed using a Kilian E150+ rotary machine (with 21 EURO D matrices) under a dry air atmosphere to form ring-like precursor moldings with the geometry A x H x I = 5 mm x 3 mm x 2 mm with a non-curved (i.e. planar) Front surface of a mass (Mv) of 102 mg is compacted (tableted). The rotor speed was 25 rpm. The lateral compressive strength (SDF _V ) of the resulting ring-like precursor moldings was 12 N. g) Thermal pretreatment and calcination of the ring-like precursor moldings produced in f).

1000 g of the precursor moldings produced were evenly divided into four grids arranged next to one another, each with a base area of 150 mm x 150 mm (filling height: 15 mm) in a flow of previously dried air (which had an inlet temperature of 140 ° C) with 4500 Nl / h Circulating air shaft furnace (company Nabertherm GmbH, D-28865 Lilienthal; furnace model S60/65A) was applied (the circulating air furnace was in an environment at 25 ° C). The temperature in the circulating air shaft furnace was then varied as follows while maintaining the air flow (including its inlet temperature) (the temperature information means the temperature in the respective applied bulk material; this was determined using four thermocouples, each of which is located in the geometric center of the four grids in the center of the the bulk material applied to the respective grid; one of the thermocouples provided the actual value for temperature control of the circulating air shaft furnace; the other thermocouples confirmed that the temperatures were identical within the interval ± 0.1 °C). The temperature increases were essentially linear over time. It was heated from 25°C to 130°C within 72 minutes. The 130°C was maintained for 72 minutes before the temperature was increased to 190°C over 36 minutes. The 190°C was held for 72 minutes before the temperature was increased to 220°C over 36 minutes. The 220°C was held for 72 minutes before the temperature was increased to 265°C over 36 minutes. The 265°C was held for 72 minutes before the temperature was increased to 380°C over 93 minutes. The 380°C was held for 187 minutes before the temperature was increased to 430°C over 93 minutes. The 430 ° C was held for 187 minutes before increasing to the final calcination temperature of 500 ° C within 93 minutes. This was maintained for 463 minutes. The mixture was then cooled to 25°C within 12 hours. For this purpose, both the heating of the circulating air shaft furnace and the air flow preheating were switched off (however, the air flow of 4500 Nl/h as such was maintained; the inlet temperature of the air flow was then 25 ° C). Example 6 (not according to the invention)

Production of the solid catalyst shaped body K6, the active multimetal oxide having the stoichiometry Moi2Co8.3Fe2.iBio,eSii,6Ko,o80 _x .

The production of the solid catalyst moldings K6 was carried out in the same way as the production of the solid catalyst moldings K5 with a modification in f).

The precursor moldings were compressed (tableted) to a mass (M _v ) of 119 mg. The lateral compressive strength (SDFv) of the resulting ring-like precursor moldings was 26 N.

Example 7

Production of the solid catalyst molding K7, the active multimetal oxide having the stoichiometry Moi2Co8.3Fe2.iBio,eSii,6Ko,o80 _x .

The production of the solid catalyst moldings K7 was carried out in the same way as the production of the solid catalyst moldings K5 with a modification in f).

The granules produced were in f) using a Korsch PH 865 rotary machine (with 65 matrices) under a dry air atmosphere to form ring-like precursor moldings with the geometry A x H x I = 5 mm x 5 mm x 2 mm with a non-curved (i.e. planar) end face Compressed (tabletted) to a mass (Mv) of 166 mg. The speed of the rotor was 40 rpm. The lateral compressive strength (SDFv) of the resulting ring-like precursor moldings was 10 N.

Example 8

Production of the solid catalyst shaped body K8, the active multimetal oxide having the stoichiometry Moi2Co8.3Fe2.iBio,eSii,6Ko,o80 _x .

The production of the solid catalyst moldings K8 was carried out in the same way as the production of the solid catalyst moldings K7 with a modification in f).

The precursor moldings were compressed (tableted) to a mass (M _v ) of 185 mg. The lateral compressive strength (SDF _V ) of the resulting ring-like precursor moldings was 16 N.

Example 9 (not according to the invention)

Production of the solid catalyst molding K9, the active multimetal oxide having the stoichiometry Moi2Co8.3Fe2.iBio,eSii,6Ko,o80 _x .

The production of the solid catalyst moldings K9 was carried out in the same way as the production of the solid catalyst moldings K7 with a modification in f).

The precursor moldings were compressed (tableted) to a mass (M _v ) of 205 mg. The lateral compressive strength (SDFv) of the resulting ring-like precursor moldings was 26 N.

Example 10 (not according to the invention)

Production of the solid catalyst shaped body K10, the active multimetal oxide having the stoichiometry [Bi2W20g 2WOs]o.4o x [Moi2Co5,4Fe3,iSii,5Ko,o80 _x ]i.

The solid catalyst moldings K10 were produced according to Example I of WO 2010/000720. The ring-like precursor moldings with the geometry A x H x I = 5 mm x 5 mm x 2 mm with a non-curved (i.e. planar) end face had a mass (Mv) of 129 mg.

Testing of the produced ring-shaped unsupported catalysts K1 to K10 for a heterogeneously catalyzed partial oxidation of propene to acrolein and acrylic acid:

A reaction tube (stainless steel type 1.4541 (EU standard number EN 10088-3); 33.7 mm outer diameter; 2 mm wall thickness; 29.7 mm inner diameter; 400 cm length, 4 mm thermal sleeve) was used for the solid catalyst moldings K1 to K6.

A reaction tube (stainless steel type 1.4541 (EU standard number EN 10088-3); 30 mm outside diameter; 2 mm wall thickness; 26 mm inside diameter; 400 cm length, without thermal sleeve) was used for the solid catalyst moldings K7 to K10.

The respective reaction tube was charged from bottom to top as follows:

Section 1: 60 cm length

Pre-fill made of steatite rings with a geometry of 7 mm x 3 mm x 4 mm (outer diameter x length x inner diameter; steatite C220 from CeramTec);

Reaction zone: consisting of 2 sections (see Table 3; zone 1 is closest to the reactor entrance)

Section 2: 30cm length

Replenishment from the same steatite rings as in section 1;

Section 3: Conduit

Table 3 shows the structure of the reaction zone. To adjust the relative volume-specific catalyst activity, solid catalyst moldings with inert steatite rings of the geometry 5 mm x 3 mm x 2 mm (outer diameter x length x inner diameter, C220 steatite from CeramTec) or the geometry 5 mm x 5 mm x 2 mm (outer diameter x length x inner diameter) were used , C220 Steatite from CeramTec).

A reaction gas mixture which had the following contents was passed through the respective reaction tube charged as described above, flowing from top to bottom through the reaction tube:

5.8 to 6.4% by volume of propene,

1.5 to 3 vol.% H ₂ O,

0.2 to 0.5 vol.% CO,

0.6 to 1.0 vol.% _CO2 ,

0.02 to 0.05 vol.% acrolein,

10.2 to 11.7% by volume of O ₂ and the remaining amount ad 100% molecular nitrogen.

The length of the reaction tube was surrounded by a stirred and electrically heated salt bath (mixture of 53% by weight potassium nitrate, 40% by weight sodium nitrite and 7% by weight sodium nitrate; 50 kg of molten salt) (the flow velocity on the tube was 3 m ³ /h (in the plane perpendicular to the longitudinal axis of the pipe)).

The temperature in the catalyst bed of the solid catalysts K1 to K6 was moved from bottom to top in the reactor bed by a thermocouple, which was placed in a thermosleeve located inside the reactor tube, with the help of a tractor was measured continuously. The maximum temperature of this measurement corresponded to the hot spot temperature T ^H .

The drop test is carried out in this paper as follows:

50 g of solid catalyst moldings are dropped through a 3.5 m long vertical tube with a clear diameter of 23 mm. The solid catalyst molded body falls into a porcelain bowl located directly below the tube and is separated from the dust and breakage generated by the impact. The intact solid catalyst moldings separated from the dust and breakage are weighed. The proportion of broken solid catalyst moldings is determined by comparing the mass determined here with the mass of the solid catalyst moldings used. The proportion of broken solid catalyst moldings is a measure of the mechanical resistance of the solid catalyst moldings.

In this document, the selectivity of value product formation (S (mol%)) is understood to mean:

Number of moles of propene converted to acrolein and acrylic acid x 100

S = -

Number of moles of propene converted in total

(the sales figures are based on a single passage of the reaction gas mixture through the fixed catalyst bed).

The comparison of the respective example pairs E1/E2, E3/E4 and E5/E6 and the comparison of Examples E7 and E8 with Examples E9 and E10 show a significantly higher selectivity of valuable products and a significantly higher yield of valuable products (with a lower catalyst mass) of the shaped unsupported catalyst bodies according to the invention. At the same time, the shaped solid catalyst bodies according to the invention have sufficient mechanical stability.

Table 1: Precursor moldings/solid catalyst moldings

) Comparative example weight loss weight loss during thermal treatment DFv side pressure resistance

Table 2: Solid catalyst moldings

) Comparative example ET = BET surface V = total pore volume of the pores with a diameter of >0.03 to <300 pm V (0.01-0.1) = volumetric proportion of pores with a diameter of >0.01 to <0.1 pm in the total pore volume V (0.1-1 ) = volumetric proportion of pores with a diameter of >0.1 to <1 pm in the total pore volume V (1-10) = volumetric proportion of pores with a diameter of >1 to <10 pm in the total pore volume V (10-300): = volumetric Proportion of pores with a diameter of >10 to <300 pm in the total pore volume

Table 3: Filling the reaction tubes

) Comparison example

Table 4: Reaction conditions/yield

) Comparative example rope load Quotient of propene flow rate (Nl/h) and empty tube volume of the reaction zone (I) selectivity value product selectivity (acrolein + acrylic acid) us yield value product yield (acrolein + acrylic acid)

Claims

Patent claims

1. A process for producing unsupported shaped catalyst bodies for the gas phase oxidation of an aikene and/or an alcohol to form an α,ß-unsaturated aldehyde and/or an α,ß-unsaturated carboxylic acid, wherein the unsupported shaped catalyst bodies comprise at least the elements molybdenum, bismuth, iron and cobalt, wherein a) an aqueous solution or aqueous suspension is produced from at least one source of the elemental constituents molybdenum, bismuth, iron, cobalt and optionally at least one source of the elemental constituent nickel, b) by drying the aqueous solution or aqueous suspension obtained in a). and optionally comminution, a powder P is produced, c) that powder P obtained in b), optionally with the addition of one or more auxiliaries and after uniform mixing and optional compaction, is compacted into precursor moldings with a cylindrical structure, and d) in c) obtained precursor moldings are thermally treated to form the solid catalyst moldings, characterized in that the pressure during compression in c) is selected so that the density of the precursor moldings is from 1.70 to 2.30 g / cm ³ , the density of the precursor moldings is the quotient of the mass and the geometric volume, and the weight loss during the thermal treatment in d) is from 25 to 40% by weight.

2. The method according to claim 1, characterized in that the cylindrical structure is i) a cylindrical body with a circular through-hole in the center in the longitudinal direction or ii) a cylindrical body which is evenly notched three times in the longitudinal direction and has three circular through-holes which are evenly arranged in the longitudinal direction .

3. The method according to claim 1 or 2, characterized in that the molybdenum content of the unsupported catalyst moldings, calculated as moss, is from 45 to 75% by weight.

4. The method according to any one of claims 1 to 3, characterized in that the bismuth content of the unsupported catalyst moldings, calculated as Bi ₂ Ö3, is from 1 to 20% by weight.

5. The method according to any one of claims 1 to 4, characterized in that the iron content of the solid catalyst moldings, calculated as Fe ₂ Ö3, is from 2 to 12% by weight.

6. The method according to any one of claims 1 to 5, characterized in that the content of cobalt and nickel in the solid catalyst moldings, calculated as Coö and Niö, is a total of 9 to 30% by weight.

7. Unsupported shaped catalyst body with a cylindrical structure for the gas phase oxidation of an Aikens and / or an alcohol to an a, ß-unsaturated aldehyde and / or an a, ß-unsaturated carboxylic acid, obtainable according to a process of claims 1 to 6, wherein the unsupported shaped catalyst body at least Elements include molybdenum, bismuth, iron and cobalt, the density of the solid catalyst shaped body being from 1.20 to 1.70 g/cm ³ is, where the density of the unsupported shaped catalyst body is the quotient of the mass and the geometric volume, the total pore volume of the unsupported shaped catalyst body is from 0.33 to 0.60 cm ³ /g and the pore volume of the unsupported shaped catalyst body is in the range of 0.1 to 1 pm 85 to 99% of the total pore volume, the total pore volume and the pore volume in the range from 0.1 to 1 pm being determined by mercury porosimetry.

8. Solid catalyst molded body according to claim 7, wherein the cylindrical structure is i) a cylindrical body with a circular through-hole opening in the center in the longitudinal direction or ii) a cylindrical body which is evenly notched three times in the longitudinal direction and has three circular through-holes which are evenly arranged in the longitudinal direction.

9. Solid catalyst molding according to claim 8, wherein the shortest distance between the outer wall of the cylindrical body and the next through opening is from 0.75 to 2.5 mm.

10. Unsupported shaped catalyst body according to one of claims 7 to 9, wherein the density of the unsupported shaped catalyst body is from 1.35 to 1.55 g/cm ³ .

11. Unsupported shaped catalyst body according to one of claims 7 to 10, wherein the total pore volume of the unsupported shaped catalyst body is from 0.36 to 0.45 cm ³ /g.

12. Unsupported catalyst molding according to one of claims 7 to 11, wherein unsupported catalyst molding according to one of claims 7 to 9, wherein the pore volume of the unsupported catalyst molding is in the range from 0.1 to 1 pm of 88 to 96% of the total pore volume

13. A process for producing an α,β-unsaturated aldehyde and/or an α,β-unsaturated carboxylic acid, wherein an alkene and/or an alcohol with molecular oxygen over a fixed catalyst bed which is a bed of unsupported shaped catalyst bodies according to one of claims 7 up to 12 includes.

14. The method according to claim 13, characterized in that the propene is used as an alkene.

15. Fixed bed reactor containing a bed of solid catalyst moldings according to one of claims 7 to 12.