Method for producing a shaped bulk catalyst body for the gas-phase oxidation of alkenes and / or alcohols to form α,β-unsaturated aldehydes and / or α,β-unsaturated carboxylic acids

Abstract

The present invention relates to a method for producing a shaped unsupported catalyst body for the gas-phase oxidation of alkenes and / or alcohols to α,β-unsaturated aldehydes and / or α,β-unsaturated carboxylic acids, the method comprising the steps of: 3 and heat-treating the shaped precursor, wherein the weight loss during the heat treatment is 25% to 45% (by weight).

Description

[Technical Field]

[0001] The present invention relates to a method for producing a shaped unsupported catalyst body for the gas-phase oxidation of alkenes and / or alcohols to α,β-unsaturated aldehydes and / or α,β-unsaturated carboxylic acids, the method comprising the steps of: 3 and heat-treating the shaped precursor, wherein the weight loss during the heat treatment is 25% to 45% (by weight).

[0002] The invention also relates to the shaped unsupported catalyst bodies obtainable according to the invention and to their use for heterogeneously catalyzed partial gas-phase oxidation in a fixed catalyst bed. [Background technology]

[0003] US Patent Application Publication No. 2005 / 0065371 describes a shaped catalyst body comprising at least the elements molybdenum, bismuth and iron for gas phase oxidation.

[0004] US Patent Application Publication No. 2006 / 0036111 discloses a method for vapor-phase oxidation to produce α,β-unsaturated aldehydes and / or α,β-unsaturated carboxylic acids, and the ignition loss during the calcination process must be within the range defined therein.

[0005] WO 2010 / 000720 teaches a method for producing shaped unsupported catalyst bodies.

[0006] WO 2013 / 007736 discloses a shaped unsupported catalyst body for gas-phase oxidation, comprising at least the elements molybdenum, bismuth, iron, and cobalt, wherein the elements bismuth, iron, and cobalt must be present in a specified ratio.

[0007] WO 2015 / 067659 describes a hollow cylindrical shaped catalyst body having a specific geometric shape. The shaped unsupported catalyst body has high stability and high selectivity for valuable products in the gas-phase oxidation of propene to acrolein and acrylic acid.

[0008] WO 2021 / 239483 discloses shaped unsupported catalyst bodies having a predetermined cylindrical structure, which enable high packing density and low pressure drop in the shaped catalyst bed.

[0009] None of the above cited patent applications acknowledges any importance to the pressure exerted in the production of the shaped precursor or the density of the shaped precursor. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] US Patent Application Publication No. 2005 / 0065371 [Patent Document 2] US Patent Application Publication No. 2006 / 0036111 [Patent Document 3] International Publication No. 2010 / 000720 [Patent Document 4] International Publication No. 2013 / 007736 [Patent Document 5] International Publication No. 2015 / 067659 [Patent Document 6] International Publication No. 2021 / 239483 Summary of the Invention [Problem to be solved by the invention]

[0011] The object of the present invention was to provide an improved process for producing an unsupported catalyst for the gas-phase oxidation of alkenes and / or alcohols to α,β-unsaturated aldehydes and / or α,β-unsaturated carboxylic acids. The catalyst should have improved selectivity to valuable products and improved yields of valuable products. "Value products" here means the total amount of acrolein and acrylic acid. [Means for solving the problem]

[0012] The object of the present invention is a method for producing a shaped unsupported catalyst body for the gas-phase oxidation of alkenes and / or alcohols to α,β-unsaturated aldehydes and / or α,β-unsaturated carboxylic acids, comprising the steps of: the shaped unsupported catalyst body comprises at least the elements molybdenum, bismuth, iron, cobalt, and optionally nickel; a) producing an aqueous solution or suspension, in each case using at least one source of the elemental components molybdenum, bismuth, iron, cobalt and optionally at least one source of the elemental component nickel, b) a powder P is prepared by drying and optionally grinding the aqueous solution or suspension obtained in a), c) The powder P obtained in b), optionally with the addition of one or more auxiliaries, is homogeneously mixed and optionally compacted, and then compacted into a shaped precursor having a cylindrical structure, d) subjecting the shaped precursor obtained in c) to a heat treatment to form a shaped unsupported catalyst body; c) The pressure in the consolidation is set to a value in which the density of the molding precursor is 1.70 to 2.30 g / cm 3 (The density of the shaped precursor is the quotient of the mass divided by the geometric volume), and d) the weight loss during the heat treatment is selected to be 25% to 40% (by weight).

[0013] The geometric volume is the macroscopic volume of the shaped precursor, including the pores. For the sake of completeness, it is emphasized that essentially circular openings and any surface structures, such as grooves, notches or spikes, are not part of the macroscopic volume.

[0014] The cylindrical structure is preferably a cylinder having at least one circular opening in the longitudinal direction. In the case of one opening, it is located in the center (hollow cylinder). In the case of multiple openings, they are uniformly distributed across the cross section of the cylindrical structure. A cylindrical structure having three openings is described, for example, in WO 2021 / 239483.

[0015] The heat treatment includes any thermal pretreatment and the actual firing.

[0016] The pressure in the consolidation of step c) is preferably set so that the density of the molding precursor is 1.72 to 2.28 g / cm 3 , more preferably 1.74 to 2.26 g / cm 3 , particularly preferably 1.76 to 2.24 g / cm 3 , very particularly preferably 1.78 to 2.22 g / cm 3 , and most preferably 1.80 to 2.20 g / cm 3 Select to be.

[0017] The weight loss in the heat treatment d) is preferably 26% to 39% (by weight), more preferably 27% to 38% (by weight), particularly preferably 28% to 37% (by weight), very particularly preferably 29% to 36% (by weight), most preferably 30% to 35% (by weight).

[0018] Weight loss during heat treatment can be controlled, for example, by using materials that are destroyed during the heat treatment.

[0019] Suitable cylindrical structures are a cylinder with a central circular opening in the longitudinal direction (hollow cylinder) and a cylinder with three uniformly cutouts in the longitudinal direction and three uniformly spaced circular openings in the longitudinal direction, the latter cylindrical structure being described in WO 2021 / 239483.

[0020] The shortest distance between the outer wall of the cylinder and the nearest opening is preferably 0.75 to 2.5 mm, more preferably 0.8 to 2.0 mm, particularly preferably 1.0 to 1.8 mm, very particularly preferably 1.2 to 1.7 mm, and most preferably 1.3 to 1.6 mm. In the case of a hollow cylinder, the shortest distance between the outer wall of the cylinder and the nearest opening corresponds to the wall thickness of the hollow cylinder.

[0021] The molybdenum content of the shaped unsupported catalyst bodies, calculated as MoO3, is preferably 45% to 75% (by weight), more preferably 50% to 70% (by weight), and most preferably 55% to 65% (by weight).

[0022] The bismuth content of the shaped unsupported catalyst bodies, calculated as Bi2O3, is 1% to 20% (by weight), more preferably 2% to 15% (by weight), and most preferably 3% to 10% (by weight).

[0023] The iron content of the shaped unsupported catalyst bodies, calculated as Fe2O3, is 2% to 12% (by weight), more preferably 3% to 11% (by weight), and most preferably 4% to 10% (by weight).

[0024] The total cobalt and nickel content of the shaped unsupported catalyst body, calculated as CoO and NiO, is 9% to 30% (by weight), more preferably 12% to 27% (by weight), and most preferably 15% to 24% (by weight).

[0025] The shaped unsupported catalyst bodies may further comprise elemental potassium and / or silicon.

[0026] The present invention further relates to a shaped unsupported catalyst body having a cylindrical structure produced by the process of the present invention for the vapor phase oxidation of alkenes and / or alcohols to α,β-unsaturated aldehydes and / or α,β-unsaturated carboxylic acids, wherein the shaped unsupported catalyst body comprises at least the elements molybdenum, bismuth, iron and cobalt, and the density of the shaped unsupported catalyst body is 1.20 to 1.70 g / cm. 3where the density of the shaped unsupported catalyst body is the mass divided by the geometric volume, and the total pore volume of the shaped unsupported catalyst body is between 0.33 and 0.60 cm 3 / g, and the pore volume in the range of 0.1 to 1 μm of the shaped unsupported catalyst body is 85% to 99% of the total pore volume, and the total pore volume and the pore volume in the range of 0.1 to 1 μm are determined by mercury porosimetry.

[0027] The geometric volume is the macroscopic volume of the shaped unsupported catalyst body, including the pores. For the sake of completeness, it is emphasized that essentially circular openings and any surface structures, such as grooves, notches or spikes, are not part of the macroscopic volume.

[0028] The density of the shaped unsupported catalyst body is preferably 1.22 to 1.68 g / cm 3 , more preferably 1.24 to 1.66 g / cm 3 , particularly preferably 1.26 to 1.64 g / cm 3 , very particularly preferably 1.28 to 1.62 g / cm 3 , and most preferably 1.30 to 1.60 g / cm 3 is.

[0029] The total pore volume of the shaped unsupported catalyst body is preferably 0.34 to 0.58 cm 3 / g, more preferably 0.35 to 0.56 cm 3 / g, particularly preferably 0.36 to 0.54 cm 3 / g, very particularly preferably 0.37 to 0.52 cm 3 / g, most preferably 0.38 to 0.50 cm 3 / g.

[0030] The volume of pores in the 0.1 to 1 μm range of the shaped unsupported catalyst body is preferably 86% to 98% of the total pore volume, more preferably 87% to 97%, particularly preferably 88% to 96%, and most preferably 89% to 95%.

[0031] Preferred shaped unsupported catalyst bodies are multi-element oxides of general formula I Mo 12 Bi a Fe b Co c Ni d X e Y f Z g O n (I) (In the formula, 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=0.2~2 b=1~4 c=3~9 d=0~4 c+d=4~9.5 e=0.01~0.5 f=0~10 g=0~10 n = a number determined by the valence and periodicity of elements in general formula I other than oxygen

[0032] The present invention further provides a process for preparing an α,β-unsaturated aldehyde and / or an α,β-unsaturated carboxylic acid, comprising passing an alkene and / or an alcohol, particularly propene, together with molecular oxygen over a fixed catalyst bed comprising a bed of the shaped unsupported catalyst body of the present invention and a fixed bed reactor comprising a bed of the shaped unsupported catalyst body of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0033] The present invention is based on the finding that the pressure consumed in the production of the shaped body precursor and the weight loss that occurs in the heat treatment have a significant effect on the value product selectivity and value product yield.

[0034] The preparation of the shaped unsupported catalyst body is described below.

[0035] The shaped unsupported catalyst bodies obtained according to the present invention are typically formed into substantially geometrically shaped bodies, calcined, and used to catalyze the respective heterogeneously catalyzed gas-phase partial oxidation (especially that of propene to acrolein). In principle, the desired geometric shape of the unsupported catalyst is not subject to any restrictions.

[0036] In principle, shaped unsupported catalyst bodies can be produced in a simple manner by using appropriate sources of their elemental components (especially other than oxygen) to produce a highly homogeneous, preferably finely divided, dry mixture of the corresponding composition corresponding to the respective stoichiometry of the shaped unsupported catalyst bodies to be produced, which is then calcined at a temperature of 350 to 650 °C after prior shaping into shaped precursors, optionally with the addition of shaping aids. Calcination can be carried out either under an inert gas or oxidizing atmosphere, such as air (or another mixture of an inert gas and molecular oxygen, which may contain a relatively small proportion of reducing components), or under a reducing atmosphere (e.g., a mixture of an inert gas, NH3, CO and / or H2, which may also contain a relatively small proportion of oxidizing components), or under reduced pressure. Calcination times can range from a few minutes to several days, typically shorter at higher calcination temperatures.

[0037] Useful sources of elemental components of the shaped unsupported catalyst bodies (i.e., starting compounds comprising at least one elemental component (at least one element present in the shaped unsupported catalyst bodies) in chemically bound form) include compounds (e.g., metal oxides) that are already oxides (generally in the solid state of matter under standard conditions (1 atmosphere, 0°C)) and / or compounds (generally in the solid state under standard conditions) that can be converted to oxides by heating (thermal treatment at high temperatures) in the presence of at least gaseous oxygen and / or a component that releases gaseous (e.g., molecular) oxygen. In principle, the oxygen source can be in the form of, for example, a peroxide component of the mixture to be calcined. It is quite common for one starting compound to be the source of more than one elemental component of the shaped unsupported catalyst bodies.

[0038] As well as the oxides, useful starting compounds (sources) of this type include, in particular, the halides, nitrates, formates, acetates, oxalates, citrates, carbonates, ammine complexes, ammonium salts and / or hydroxides and hydrates of the aforementioned salts.

[0039] Compounds that essentially completely destroy and / or decompose during subsequent calcination or earlier to yield compounds that escape in gaseous form (e.g., ammonia, CO2, CO, HO, nitrogen oxides), such as NH4OH, (NH4)2CO3, NH4NO3, NH4CHO2, CH3COOH, NH4CH3CO2, and / or ammonium oxalate, can further be incorporated into the homogeneous dry mixture. Useful substances of this type that are destroyed in the calcination operation also include organic materials such as stearic acid, malonic acid, ammonium salts of the aforementioned acids, starches (e.g., potato starch, corn starch), ground nutshells, and finely divided polymers (e.g., polyethylene, polypropylene, etc.).

[0040] If the element sources from which a highly homogeneous, 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 contain hydroxide, carbonate, bicarbonate, ammonium, halide, hydrogen phosphate and / or nitrate ions which are usually destroyed in the calcination operation, gaseous compounds are also usually formed (evolved) during the heat treatment outlined.

[0041] The homogeneous mixing of the starting compounds (sources) for producing the shaped unsupported catalyst bodies can be carried out in dry or wet form. When carried out in dry form, the starting compounds (sources) are suitably used in the form of fine powder, and after mixing and compaction, a geometrically shaped precursor is obtained, which is then subjected to calcination.

[0042] However, preferably, according to the invention, the homogeneous mixing of the (elemental) sources is carried out in wet form.

[0043] In this case, the starting compounds in the form of a solution and / or suspension are mixed with one another and the resulting wet (preferably aqueous) mixture M is then dried to obtain a homogeneous dry mixture. The solvent and / or suspension medium used is preferably water or an aqueous solution, and the aqueous mixture M is obtained as the wet mixture M.

[0044] When the starting materials are the source of elemental components exclusively in dissolved and / or colloidally dissolved form, a particularly homogeneous dry mixture is obtained by the above-mentioned mixing process. As already mentioned, the starting compounds may be the source of only one or more elemental components. In a corresponding manner, the above-mentioned solution or colloidal solution may contain only one or more elemental components of the relevant shaped unsupported catalyst body produced in dissolved form. As already mentioned, the preferred solvent here is water. Drying of the resulting aqueous mixture is preferably carried out by spray drying.

[0045] When this specification refers to a solution of a source (starting compound, starting material) in a solvent (especially water), the term "dissolved" refers to the meaning of a molecular or ionic solution. This means that the largest geometric unit of the dissolved starting material (source) present in the solution necessarily has "molecular" dimensions and the solution is "visually empty".

[0046] In contrast, colloidal solutions constitute a bridge between true (molecular and / or ionic) solutions and suspensions. In these colloidally dispersed systems, there are tiny deposits of molecules or atoms, which are not apparent to the naked eye or even under a microscope. Colloidal solutions have a completely transparent (often colored) visual appearance because the particles present therein have diameters of only 1-250 nm (preferably up to 150 nm, more preferably up to 100 nm).

[0047] Due to their small size, colloidally dissolved particles cannot be removed by conventional filtration. However, they can be separated from their "solvent" by ultrafiltration using membranes of plant, animal, or synthetic origin (e.g., parchment, pig bladder, or cellophane). In contrast to a true "visually empty" (molecular and / or ionic) solution, a light beam cannot pass through a colloidal solution without being deflected. The light beam is scattered and deflected by the colloidally dissolved particles. To keep colloidal solutions stable and prevent further particle aggregation, they often contain added wetting and dispersing aids and other additives.

[0048] The elements other than silicon (elemental components) for the shaped unsupported catalyst body are preferably introduced by a dissolved source in the form of a solution (more preferably in an aqueous solution) for the preparation of the wet (preferably aqueous) mixture M, whereas elemental silicon is preferably introduced in the form of a silica sol for the preparation of the wet (preferably aqueous) mixture M.

[0049] Silica sol is an aqueous colloidal solution of substantially spherical polysilicic acid particles. The particle diameter is in the colloidal range, between 5 and 75 nm depending on the type. The particles are non-porous. They have a hydroxylated SiO2 core on their surface. The individual spherical particles are not cross-linked to each other. For stability reasons, in silica sol, some of the hydroxyl groups are usually in neutral form with alkali metal hydroxides and / or ammonium hydroxides. This is because some of the counterions in this case are not protons but alkali metal ions (e.g., Na). + ) and / or NH4 + This means that it is cationic. The SiO2 content of silica sols suitable for producing the wet (preferably aqueous) mixture M can be, for example, 30% to 60% by weight of the silica sol. Silica sols are usually water-fluid and do not contain any sedimentary components. They can often be kept for years without settling.

[0050] A particularly suitable Si source is LUDOX® silica sol from Grace GmbH & KG, In der Hollerecke 1, D-67545 Worms. The particles are discrete spherical spheres of silicon dioxide with no internal surface area or detectable crystallinity. Most of them are dispersed in an alkaline medium, which reacts with the hydroxylated surface and produces a repulsive negative charge.

[0051] The particle size of suitable silica sols may be very narrow (essentially monodisperse) or very broad (polydisperse).

[0052] A silica sol particularly suitable for the purposes of the present invention (for the preparation of the wet (preferably aqueous) mixture M) is LUDOX TM50 silica sol from Grace. LUDOX TM50 silica sol has a very substantially monodisperse particle size distribution (d=22 nm). Its pH (1 atmosphere, 25°C) is 9.0. The alkali metal ions replacing some of the hydroxyl protons are Na + The SiO2 content of LUDOX TM50 is 50% by weight of this hydrogel. The specific surface area of ​​the SiO2 particles present in colloidal dissolved form in LUDOX TM50 is 140 m 2 / g. The bulk density of LUDOX TM50 (at 1 atmosphere, 25°C) is 1.40 g / cm 3 The titratable alkali metal content (calculated as Na2O) of LUDOX TM50 is 0.21% (by weight) (based on the weight of the silica sol).

[0053] The kinematic viscosity of LUDOX TM50 is 40 mPas (1 atmosphere, 25°C). - The content (calculated as NaCl) of LUDOX TM50 is 0.03% (by weight), and the SO4 2- The content (calculated as Na2SO4) is 0.08% (by weight) (in each case based on the weight of LUDOX TM50).

[0054] It will be understood that at least one element source in molecularly and / or ionically dissolved form and one or more other element sources in colloidally dissolved form may also be present together in the solution used to prepare the wet (especially aqueous) mixture M.

[0055] A preferred Mo source is ammonium heptamolybdate tetrahydrate, due to its particularly good 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 atmosphere has a saturated solubility of 30% (by weight) (calculated as the anhydrous salt).

[0056] As a result of its manufacture, ammonium molybdate tetrahydrate can become contaminated with small amounts (usually ppm) of water-insoluble isopolymolybdate (as a result of inaccurate monitoring of process parameters in its manufacture). When ammonium heptamolybdate tetrahydrate contaminated in this way is dissolved in water, it produces an aqueous solution with a certain turbidity due to the small amount of finely divided isopolymolybdate present in undissolved form. In-house studies by the Applicant have shown that even isopolybate-contaminated ammonium molybdate tetrahydrate, whose solution 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 150 NTU, or 200 NTU, or 250 NTU, or 300 NTU, is suitable for the production of the shaped unsupported catalyst bodies of the present invention without appreciable impairment of its performance when used as a catalyst for the heterogeneously catalyzed partial gas-phase oxidation of propene to acrolein as the main product and acrolein as a by-product.

[0057] Further suitable Mo sources are, for example, ammonium orthomolybdate ((NH4)2MoO4), ammonium dimolybdate ((NH4)2Mo2O7), ammonium tetramolybdate dihydrate ((NH4)2Mo4O 13 × 2H2O) and ammonium decamolybdate dihydrate ((NH4)4Mo 10 O 32 × 2H2O). In principle, molybdenum trioxide can also be used.

[0058] The preferred source of alkali metals in the context of producing shaped unsupported catalyst bodies is their hydroxide. In principle, the nitrates of these elements and the hydrates of these nitrates are also useful as such sources. This means that the preferred K source is KOH, but KNO or its hydrate can also be used as a K source in principle.

[0059] The Bi source used is Bi 3+ Preferably, the salt is a bismuth salt having Bi in the form of Bi. Examples of useful salts of this type include bismuth(III) oxide, bismuth(III) nitrate oxide (bismuth subnitrate), bismuth(III) halides (e.g., fluoride, chloride, bromide, iodide), and in particular bismuth(III) nitrate pentahydrate. The Bi source used may also be a salt of bismuth having Bi in the form of Bi. 3+ It will be appreciated that the solution may be a solution of elemental Bi in aqueous nitric acid in the form of Bi 3+ When an aqueous solution of nitrate or its hydrate is used as the source (preferred in accordance with the present invention), the low pH (1 atmosphere, 25°C) of the aqueous solution leads to the formation of Bi in the aqueous solution. 3+ This is advantageous as it counteracts the undesirable formation of inclusion precipitates. The pH is preferably 1 or less, more preferably 0.5 or less. However, in general, the pH is -2 or more, usually 0 or more. Suitably, such an aqueous solution is a nitric acid solution, since its low pH prevents excess nitric acid (in this case, Bi3 present in the aqueous solution) from being dissolved. + (n Bi3+ ) relative to the molar amount of NO3 present in aqueous solution - (n NO3-) molar ratio (n NO3- ) / (n Bi3+ ) is greater than 3.

[0060] The preferred Fe source is Fe 3+ Among these, various iron(III) nitrate hydrates are particularly preferred (see, for example, DE 10 2007 003076 A1). According to the present invention, it is particularly preferred to use iron(III) nitrate nonahydrate as the Fe source for the above-mentioned purposes. Of course, it is also possible to use Fe(III) nitrate nonahydrate as the Fe source. 2+ It is also possible to use salts of

[0061] Advantageously, for the production of shaped unsupported catalyst bodies, at least 50 mol%, better still at least 75 mol%, preferably at least 95 mol% or 100 mol%, based on the total molar amount of Fe present therein, is Fe 3+ For this purpose, Fe is introduced in the form of an Fe source having Fe in the form of 3+ and Fe 3+ It is also possible to use an Fe source having both of the above.

[0062] A good suitable Co source is Co 2+ and / or Co 3+ Examples of these include cobalt(II) nitrate hexahydrate, Co3O4, CoO, cobalt(II) formate, and cobalt(III) nitrate. For the aforementioned purposes, the first of these sources is particularly preferred. The Co source used may also be one in which Co is present in the form of Co 2+ It will be appreciated that the solution may be a solution of elemental Co in aqueous nitric acid in the form

[0063] For elemental component Ni, Ni 2+It is preferable to use salts. These include, 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, as well as the respective hydrates of these salts. It is very particularly preferable to use a hydrate of nickel(II) nitrate (for example its hexahydrate) as the Ni source.

[0064] For example, the solubility of salts of Fe, Co, Cu and / or Ni in aqueous media can be improved, if necessary, by adding ammonia (or an aqueous solution thereof) and / or nitric acid (particularly as an aqueous solution thereof) to the respective solutions.

[0065] In principle, the preparation of the wet (e.g. aqueous) mixture M can be carried out under a wide variety of gas atmospheres (e.g. under air, argon, nitrogen, steam and / or carbon dioxide). Preferably, according to the invention, the preparation of the wet (e.g. aqueous) mixture M is carried out under air (advantageously, the aqueous mixture M is saturated in air). This is because the cobalt and ion source used are Co 2+ Salt and Fe 2+ This is especially true when these salts are nitrates and / or hydrates thereof.

[0066] As already mentioned, the wet mixture M according to the invention is preferably an aqueous mixture M which is particularly advantageously prepared in the following manner.

[0067] At least one elemental Fe source, at least one elemental Bi source, at least one elemental Co source, and optionally at least one elemental Ni source are used to generate an aqueous solution A having a pH of 3 or less, preferably 2 or less, more preferably 1 or less, and most preferably 0 or less. (The pH values ​​of the aqueous solutions generally (unless otherwise specified) refer to measurements using a glass electrode in the form of a combined electrode at 1 atmosphere and the temperature at which the respective aqueous solution is generated. Calibration of the combined electrode required for this purpose is performed under the same conditions using an aqueous buffer solution with a known pH under these conditions close to the desired measurement. The Mettler Toledo Inpro 4260 / 425 / Pt 100 pH electrode is particularly suitable for determining such pH values; it is a combined electrode with an integrated Pt 100 temperature sensor for automatic temperature compensation.) Generally, the pH of aqueous solution A is -2 or more, and particularly advantageously in the range of -1 to 0. Preferably, aqueous solution A is an aqueous solution of nitrates or nitrate hydrates of the aforementioned elements. More preferably, aqueous solution A is an aqueous solution of these nitrates or nitrate hydrates in aqueous nitric acid. Particularly for the preparation of such solutions, suitable element sources are also solutions of the relevant elements in aqueous nitric acid.

[0068] At least one elemental Mo source and, optionally, at least one alkali metal source are used to generate aqueous solution B. The pH of aqueous solution B (at 1 atmosphere and at the temperature at which solution B is generated) is advantageously less than 7. More preferably, the pH of aqueous solution B is less than or equal to 6.5, and very particularly advantageously less than or equal to 6. Generally, the pH of aqueous solution B will be greater than or equal to 3. Preferred solutions B for use according to the invention have a pH between 4 and 6. Preferably, according to the invention, for the preparation of aqueous solution B, the source used for the alkali metal is its hydroxide element (e.g., KOH). A preferred Mo source for preparing aqueous solution B is ammonium heptamolybdate tetrahydrate ((NH4)6Mo7O 24 × 4H2O), which dissolves completely in water at 25°C (1 atm) up to its saturated solubility (30% by weight calculated in the anhydrous form).

[0069] Suitably, according to the present invention, the total content of metal components Bi, Fe, Co, Ni, etc. in aqueous solution A is 5% to 20% (by weight), advantageously 10% to 15% (by weight), based on the total content of aqueous solution A.

[0070] Suitably, according to the invention, the total content of Mo in aqueous solution B is 2% to 25% (by weight), advantageously 3% to 20% (by weight), particularly advantageously 5% to 15% (by weight), based on the total amount of aqueous solution B.

[0071] Subsequently, aqueous solution A and aqueous solution B are appropriately mixed. The procedure here is advantageously to continuously stir aqueous solution A into aqueous solution B. This is advantageously carried out while vigorously stirring aqueous solution B, which is initially charged.

[0072] Suitably, according to the present invention, the total content of metal components Bi, Fe, Co, Ni, Mo, etc. in the obtained aqueous mixture of aqueous solutions A and B is between 3% and 20% (by weight), advantageously between 5% and 15% (by weight), based on the total content of the aqueous mixture.

[0073] The temperature of the initially charged aqueous solution B, as well as the temperature of aqueous solution A itself during stirring of aqueous solution A, is advantageously (preferably throughout the entire mixing operation) below 80° C. and above 0° C. Preferably, the aforementioned temperatures are below 75° C. and above 30° C., more preferably below 70° C. and above 50° C. or below 65° C. and above 55° C.

[0074] Advantageously, aqueous solutions A and B, and the aqueous mixture resulting from stirring aqueous solution A into aqueous solution B, have the same temperature. This temperature is at most 60°C. Preferably, the temperatures of aqueous solutions A and B and the aqueous mixture resulting therefrom are kept constant throughout the described stirring-in process. For this purpose, thermostatic control is possible, for example, with the aid of a water bath. The operating pressure when stirring aqueous solution A into aqueous solution B is suitably 1 atmosphere (1.01 bar).

[0075] Preferably, aqueous solution A is stirred in the initially charged aqueous solution B 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 then suitably stirred for a further period of 5 to 60 minutes, preferably 10 to 30 minutes, particularly advantageously 15 to 25 minutes, preferably while maintaining the stirring-in temperature.

[0076] The pH of the aqueous mixture of aqueous solutions A and B is advantageously less than or equal to 3, and better still less than or equal to 2. Generally, it is a value greater than or equal to 0.

[0077] When the shaped unsupported catalyst body contains the elemental component Si, preferably according to the present invention, an aqueous silica sol as its source is stirred into the aqueous mixture of aqueous solutions A and B, in which case water may advantageously be added to the aqueous mixture before the stirring addition. In a suitable manner, both the aqueous silica sol and water can be added at once. The temperature of both the water and the aqueous silica sol advantageously corresponds to the temperature of the aqueous mixture of aqueous solutions A and B. Finally, in a suitable manner, stirring is continued for a maximum of 30 minutes. During further stirring, the aforementioned temperature is advantageously maintained. The SiO2 content of the aqueous silica sol added 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), more preferably 45% to 55% (by weight) (in each case based on the total weight).

[0078] Instead of first placing aqueous solution B in a temperature-controlled stirred vessel and then feeding aqueous solution A therein while stirring, it is also possible to feed both aqueous solutions B and A continuously into the stirred vessel (for example, by means of a "3-way T-mixer"). In principle, aqueous solution B can also be continuously stirred into the initially charged aqueous solution A. However, this procedure is less preferred.

[0079] In general, the aqueous mixture M obtainable as described is an aqueous suspension (preferably, the ratio V described as advantageous is also present in the aqueous mixture M (the molar amount of NH3 + NH4 present relative to the molar amount of Mo present). + (total molar amount of Bi, Fe, Mo, etc.). Furthermore, the pH of the aqueous mixture M obtained as described is advantageously 3 or less, generally 0 to 2. The aqueous mixture M obtained as described advantageously contains Co and / or Ni present therein in dissolved form in the aqueous medium (at the temperature and operating pressure at which the aqueous mixture M was produced) in an amount of 60 mol% or less of the total molar amount. Preferably, the above-mentioned detailed proportion AT of the molar amount of Co and / or Ni present in the aqueous mixture M dissolved in the aqueous medium of the aqueous mixture M is a value of 50 mol% or less, more preferably 40 mol% or less, or 30 mol% or less, or 20 mol% or less. Suitably, according to the invention, the total content of Bi, Fe, Mo, etc. in the aqueous mixture M to be dried (preferably spray-dried) is 3% to 20% (by weight), advantageously 5% to 15% (by weight), based on the amount of the aqueous mixture M. Generally, AT has a value of 10 mol% or more or 15 mol% or less.

[0080] Preferably, according to the present invention, the aqueous mixture M is converted into a finely divided homogeneous dry mixture by spray-drying the aqueous mixture M (the aqueous mixture M is preferably dried as soon as possible after its production). This means that the aqueous mixture M is first divided into fine droplets (atomized) in a spray dryer, and then dried in a spray dryer. The spray drying is preferably carried out in a hot air stream. In principle, it is possible to use other hot gases (for example, nitrogen or nitrogen-diluted air and other inert gases) instead for the above-mentioned spray drying.

[0081] Spray drying can be carried out either in co-current or counter-current flow of droplets to hot gas. Typical gas inlet temperatures here are in the range of 250-450°C, preferably 270-370°C. Typical gas outlet temperatures here are in the range of 100-160°C. Spray drying is preferably carried out in co-current flow of droplets to hot gas.

[0082] The average particle size of the resulting spray powder is typically 10-100 μm, preferably 15-60 μm, more preferably 25-50 μm (diameter determined in accordance with ISO 13320-1 by light scattering on an air-dispersed spray powder (dispersion air pressure 1.0 bar)). In general, references in this specification to standards relate in each case to that version of the standard which was valid on the priority date of the present patent application and which has the smallest publication date (issue date) that differs from the priority date of the present patent application.

[0083] The tapped bulk density (25°C, 1 atmosphere) of the spray powder is typically 500 to 1300 g / L, preferably 700 to 1100 g / L.

[0084] The loss on ignition of the atomized powder (calcined under excess still air at 600°C (powder temperature) for 3 hours) is typically 20% to 40% (by weight) of its starting weight, preferably 25% to 35% (by weight).

[0085] Until further processing, the sprayed powder can be stored in an airtight container (e.g., a drum made of plastic). The storage temperature should not exceed 70°C, preferably not more than 50°C. Generally, the storage temperature is not lower than 10°C. Since sprayed powders are generally hygroscopic, prolonged contact with moist air should be avoided. Contact with moist air can impair the handling properties of the sprayed powder (e.g., the flowability of the sprayed powder) and ultimately reduce the catalytic activity of the shaped unsupported catalyst body produced using the sprayed powder.

[0086] It will be understood that the aqueous mixture M can also be dried by other drying methods, such as conventional evaporation, preferably under reduced pressure, the drying temperature generally not exceeding 150° C. In principle, the drying of the aqueous mixture M can also be carried out by freeze-drying or Spin-Flash® drying.

[0087] The sprayed powder is first coarsened, for example, by subsequent compaction. If compaction is carried out in dry form, for example, micronized graphite and / or other molding aids (e.g., lubricants, reinforcing agents, and / or pore formers) described in this document can be mixed into the sprayed powder before compaction (e.g., using a drum hoop mixer). For example, compaction can be carried out using a calender with two counter-rotating steel rolls. The compact can then be specifically ground to a particle size appropriate for the intended further use. The easiest way to do this is, for example, to force the compact through a sieve with a defined mesh size.

[0088] In principle, compaction can alternatively be carried out in wet form.For example, spray powder can be kneaded with the addition of water.After kneading, the kneaded composition can be ground back to the desired fineness that is suitable for subsequent use (see, for example, DE-A-100 49 873) and can be dried.

[0089] The finely divided precursor composition (a finely divided homogeneous dry mixture of elemental component sources) is suitably used to form shaped precursors of regular or irregular geometric shapes by compaction (pressing or compacting), which are then converted by heat treatment into shaped unsupported catalyst bodies.

[0090] Further finely divided molding aids that can be added to the finely divided precursor composition before and / or during molding include, for example, lubricants such as graphite, carbon black, polyethylene glycol, polyacrylic acid, stearic acid, starch, mineral oil, vegetable oil, water, boron trifluoride and / or boron nitride. Also useful as molding aids are reinforcing agents, such as glass, asbestos, silicon carbide or potassium titanate microfibers, which have a beneficial effect on the integrity of the resulting compaction (of the resulting compact) after compaction. Other useful molding aids include pore-forming agents, such as ammonium nitrate, ammonium carbonate, water and / or malonic acid. The pore-forming agent breaks down or evaporates during heat treatment to form pores. The additional use of lubricants in the context of corresponding forming operations is described, for example, in DE 10 2007 004961 A1, WO 2008 / 087116 A1, WO 2005 / 030393 A1, US 2005 / 0131253 A1, WO 2007 / 017431 A1, DE 10 2007 005606 A1 and DE 10 2008 040093 A1.

[0091] It is preferred to use only finely divided graphite as a lubricant. The finely divided graphite to be used is, in particular, that recommended in WO 2005 / 030393, US 2005 / 0131253, WO 2008 / 087116, and DE 10 2007 005606. This applies in particular to the graphite used in the examples and comparative examples of these documents. Very particularly preferred graphites are Asbury 3160 and Asbury 4012 from Asbury Graphite Mills, Inc., New Jersey 08802, USA, and Timrex® T44 from Timcal Ltd., Bodio, Switzerland 6743.

[0092] Based on the weight of the micronized precursor composition to be molded, the precursor composition may contain, for example, up to 15% (by weight) of a micronized lubricant (e.g., graphite) based on its total weight. However, the lubricant content in the micronized precursor composition to be molded (micronized homogeneous dry mixture) is usually 9% (by weight) or less, often 5% (by weight) or less, and often 4% (by weight) or less. This is particularly true when the micronized lubricant is graphite. Generally, the above-mentioned addition amount is 0.5% (by weight) or more, usually 2.5% (by weight) or more.

[0093] Generally, the finely divided precursor composition (a finely divided homogeneous dry mixture) optionally containing a molding aid is consolidated into the desired geometric shape of the shaped precursor by the action of an external force (pressure) on the precursor composition. There are no particular limitations on the molding device or molding method used here.

[0094] For example, compaction can be carried out by tableting. The micronized precursor composition (micronized homogeneous dry mixture) used herein is preferably dry to the touch. However, it may contain, for example, up to 10% by total weight of an additive substance that is liquid under standard conditions (25°C, 1 atmosphere (1.01 bar)). The micronized precursor composition (micronized homogeneous dry mixture) may also contain a solid solvate (e.g., hydrate) containing such a liquid substance in a chemically and / or physically bound form. It will be understood that the micronized precursor composition may also be completely free of such substances.

[0095] A preferred forming process by compaction of the micronized precursor composition (of the micronized homogeneous dry mixture) is tableting, the principles of which are described, for example, in "The Tablet", Handbook of Development, Production and Quality Assurance ["The Tablet", Handbook of Development, Production and Quality Assurance], W. A. ​​Itschel and A. Bauer-Brandl, 2nd edition, Edition Verlag Aulendorf, 2002, and can be applied in a manner that corresponds entirely to the tableting process of the present invention.

[0096] Tableting is a press agglomeration process. A free-flowing feed mixture is introduced into a press mold having a die between two punches and compacted by uniaxial compression to form a solid compact. Tableting can be divided into four parts: metering, compaction (elastic deformation), plastic deformation, and ejection. Tableting is carried out, for example, in a rotary press or an eccentric press.

[0097] The outer surface of the pressed catalyst support consists of a peripheral surface corresponding to the inner wall of the die cavity and a first end side and a second end side corresponding to the operating head of the punch. The pressed catalyst support may be flat or have a curved end, meaning that at least one of the first and second sides is curved. The curved side can be obtained, for example, by using a concave lower punch and / or upper punch. If necessary, the upper punch and / or lower punch may be provided with a protruding pin to form an internal passage. It is also possible to provide a press punch with multiple pins, so that a punch can be produced with, for example, four pins to produce a molded body having four holes (passages). Typical structural features of such press dies can be found, for example, in U.S. Pat. No. 8,865,614.

[0098] A press die typically consists of a die, an upper punch, a lower punch, and a pin (if the compact has a passage). Suitable materials for press dies are tool steels, cemented carbides based on tungsten carbide (WC), and ceramic materials. Tool materials with a hardness of more than 55 on the Rockwell C scale are preferred. Examples of tool steel materials are DIN tool steels 1.2210, 1.2343, 1.2436, 1.2379, 1.2601, 1.2080, and 1.25550, as well as high-speed steels such as Vanadis 4 Extra from Uddeholm D-40549 Dusseldorf and Vanadis 8 from Uddeholm D-40549 Dusseldorf. Suitable WC-based materials are described in U.S. Pat. No. 8,865,614. Examples of such WC-based materials are G10-Ni from Hartmetall® Gesellschaft, D70497 Stuttgart and htc-KR17® from Hightech-Ceram®. An example of a ceramic material is yttrium-stabilized zirconia (YSZ).

[0099] WC-based hard metal and ceramic materials are particularly suitable for tooling applications where a lined die made of WC-based hard metal or ceramic, for example 1.2379, is inserted into a steel housing made of tool steel.

[0100] Press dies typically have a surface coating to improve surface hardness, corrosion resistance, wear resistance, friction, and non-stick properties. Examples of surface coatings include diamond-like carbon (DLC), boron nitride, titanium nitride, chromium nitride, chromium plasma coating, and hard chrome plating. The layer thickness is 1 to 10 μm, preferably 1 to 5 μm.

[0101] The surfaces of the press dies that come into contact with the feed mixture and the resulting tablets preferably have a low surface roughness: the arithmetic mean roughness Ra according to DIN 4768 of the press dies surfaces should preferably be 0.01 to 0.5 μm, more preferably 0.02 to 0.3 μm, even more preferably 0.02 to 0.2 μm, and most preferably 0.02 to 0.1 μm.

[0102] The length of the tip, specifically the lower punch, is preferably 2 to 7 mm, more preferably 2 to 6 mm, and most preferably 2.5 to 5 mm. Too long a tip length can result in high friction, especially when sticking of the molded precursor occurs. The tip, specifically the upper and lower edges of the lower jaw, are preferably sharp rather than rounded. Sharp edges reduce powder clogging at the stamp-stamp interface and pinhole interface (in the case of tablet dies with channels). Powder clogging can result in both sticking and powder leakage.

[0103] In particular, the tip length of the upper punch is preferably greater than 2 mm, typically in the range of 2 to 10 mm. In contrast to the lower punch, a high tip length does not cause friction problems, since the upper punch is introduced into the die by only a few millimeters during the tableting cycle.

[0104] If the tableting die has a passageway, the lower punch and the upper punch have holes to accommodate the pins. The upper punch should have at least one vent hole that allows air to escape from the die cavity through the upper stamp hole to the outside of the upper stamp hole during compaction. Such an upper punch with a vent opening hole is specified in U.S. Patent Application Publication No. 2010 / 0010238 (see Figures 4a, 4b, 4c, and 4d).

[0105] The distance between the nozzle hole and the lower outer surface of the stamp is preferably 3 to 50 μm, more preferably 5 to 35 μm, and most preferably 6 to 26 μm. Similarly, the distance between the die hole and the upper outer surface of the stamp is preferably 3 to 50 μm, more preferably 5 to 35 μm, and most preferably 6 to 26 μm. This distance is ensured by selecting an appropriate combination of dimensional tolerances for the die and lower punch. Dimensional tolerances are typically indicated by ISO wave tolerances defined in ISO 286-2. Examples of dimensional tolerance combinations for the nozzle hole and the outer surface of the punch indicated in the ISO tolerance code are H6 / f7, H6 / g6, H6 / g7, H7 / g6, H7 / f7, F8 / h6, G7 / h6, and F7 / h6 (nozzle hole / lower outer surface of punch).

[0106] When the tablet shape has a passage, the press die is provided with a pin. The distance between the pin and the pin hole of the lower punch is preferably 3 to 50 μm, more preferably 5 to 35 μm, and most preferably 6 to 26 μm. As with the distance between the die hole and the outside of the stamp, this distance is ensured by selecting an appropriate combination of dimensional tolerances for the die and the lower punch.

[0107] The die hole preferably has a slight constriction starting from a predetermined depth toward the upper end of the die. The constriction of the nozzle hole gradually increases in hole size toward the upper end of the nozzle, which creates additional distance between the nozzle hole wall and the inclined outer surface of the lower punch. The additional space facilitates the escape of air present in the mixed feed during compression in the die, thereby mitigating powder blow-in and resulting unstable tableting due to poor air escape. An additional advantage of the conical die is the facilitated ejection after compaction. Compaction into a tablet at the point where the die hole has a constriction results in a tablet with a slightly constricted outer surface for molding through the conical die hole. During the ejection phase, when the lower punch pushes the tablet upward in the die, the slight rise of the tablet forces the tablet to be removed from the die wall by the constriction structure, so the tablet is easily ejected from the die wall. If the die hole does not have a constriction, there is no detachment of the tablet from the die wall, and the entire injection process (i.e., the rise of the tablet from the depth above the nozzle where compression occurs) is subject to friction between the outer surface of the tablet and the die wall, and between the straight outer surface of the tip and the nozzle wall, which results in undesirably high ejection forces.

[0108] The depth of the matrix constriction (i.e., the depth from the upper surface of the die) should be selected so that the formed tablet is primarily within the conical zone before ejection. To achieve this, the constriction depth may be oriented by adding the tablet height in the die before elastic recovery (i.e., the minimum distance between the upper and lower punches) and the insertion depth of the upper punch. For example, for an upper punch insertion depth of 2 mm and a tablet height in the die of 12 mm, a constriction depth of 12-15 mm may be used.

[0109] The die constriction angle is typically 0.1° to 0.6°, and the increase in size of the upper die hole is preferably 0.03 to 0.2 mm, more preferably 0.05 to 0.14 mm. The increase in size can be mathematically derived from the constriction angle and the constriction depth.

[0110] If the tablet shape has a passageway, the press die is provided with a pin. The pin is fixed on the revolver so that it is in the die cavity where the tablet is formed to leave a passageway for the tablet. Like the die, the pin does not move vertically during the tableting cycle, in contrast to the upper and lower punches. The vertical surface of the upper end of the pin is the same as or slightly lower than the height of the upper end face of the die. In particular, if the tablet has curved sides and the lower stamp face has a concave surface, the vertical surface of the upper end of the pin must be somewhat lower than the level of the upper front face of the die so that the pin does not protrude from the lower stamp face.

[0111] When the tablet shape has a passageway, it often adheres to the pin surface, which leads to drawbacks such as high ejection force due to high friction at the pin-tablet interface. This problem is particularly pronounced in the case of multiple dies with multiple pins. Typically, the pins are more prone to sticking than the die wall and especially the tips of the lower jaws.

[0112] When the tablet shape has a passageway, the pin preferably has a slight constriction in the upper region over a specified length. The constriction of the pin indicates a gradual decrease in the pin diameter toward the top of the pin. The main advantage of a conical pin is the facilitated ejection after compaction. When the pin is compacted into a tablet at the constriction, the resulting tablet passageway has a slightly constricted inner side as a result of the constricted pin. The diameter of the tablet passageway decreases slightly from the bottom upward along the axial axis. During the ejection phase, when the lower punch pushes the tablet upward in the die, the pin and die remain vertically immobile, but when the tablet rises slightly, the constricted structure allows the tablet to be easily ejected from the pin. If the pin does not have a constriction, the tablet will not separate from the pin, and therefore the entire ejection process (i.e., the tablet lifting from the depth where it was compressed on the top face of the die) is subject to friction at the tablet-pin interface, resulting in a high ejection force. Conical pins are particularly advantageous when the tablet has multiple passageways.

[0113] The length of the pin constriction should be selected so that the tablet formed before injection is primarily within the conical zone. To achieve this, the length of the pin constriction can be oriented by summing the tablet height in the die before elastic recovery (i.e., the minimum distance between the upper and lower punches) and the insertion depth of the upper punch. For example, for a 12 mm tablet height in the die with an upper punch insertion depth of 2 mm, a constriction length of 12 to 15 mm can be used.

[0114] The die constriction angle is typically 0.1° to 0.6°, and the upper pin diameter reduction is preferably 0.05 to 0.3 mm, more preferably 0.1 to 0.2 mm. The reduction can be mathematically derived from the constriction angle and the constriction length.

[0115] Industrial mass production of tablets is preferably carried out using a rotary tablet press. Conventional rotary presses can be used in the present 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.

[0116] The rotary press typically has two compaction rolls for performing two-stage compaction including pre-compaction and main compaction. The main compaction pressure is in the range of 5 to 500 MPa, preferably 8 to 400 MPa, and more preferably 10 to 300 MPa. The pre-compaction pressure is typically in the range of 5% to 50%, preferably 7% to 40%, and more preferably 10% to 35% of the applied main compaction pressure.

[0117] The pressing die is selected according to the desired geometric dimensions of the compacted body. The size and shape of the compacted body, and therefore the catalyst, are selected so that the catalyst body obtained from the compacted body can be properly packed into a reactor tube. Catalysts obtained from compacted bodies suitable for the catalyst of the present invention are preferably used in reactor tubes having a length of 6 to 14 m and an inner diameter of 20 mm to 50 mm. Generally, the support consists of individual bodies having a maximum extent in the range of 3 to 20 mm, for example 4 to 15 mm, particularly 5 to 12 mm. The maximum extent refers to the longest straight line between two points on the periphery of the support.

[0118] The shape of the compacted body is not particularly limited and can be any shape technically conceivable, for example, depending on the molding process. For example, the tablet may be a solid tablet or a hollow tablet, such as a hollow cylinder. In a further embodiment, the pillar may be characterized by a multi-lobed structure. A multi-lobed structure is considered to refer to a cylindrical structure having multiple cavities, such as grooves or grooves, extending around the circumference of the cylinder along the height of the cylinder. Generally, the cavities are arranged essentially equidistantly around the circumference of the cylinder.

[0119] The compression force during tableting affects the compaction of the free-flowing feed mixture and therefore, for example, the density and / or mechanical stability of the compacted body. In practice, it has been found desirable to control the lateral compression strength of the tableted catalyst support by selecting an appropriate compression force and verify it by sampling. For the purposes of the present invention, the lateral compression force is the force that breaks a catalyst pillar that has been tableted between two flat parallel plates, with the two flat parallel end faces of the catalyst pillar at right angles to the flat parallel plates.

[0120] To improve the tableting properties, the free-flowing feed mixture may be subjected to further processing, for example by sieving, preheating and / or pre-pelletizing, i.e., pre-compaction. For pre-pelletizing, it is possible to use a roll compactor, for example a Chilsonator® from Fitzpatrick.

[0121] Further information regarding tabletting, particularly regarding pre-pelletization, sieving, lubricants and dies, can be found in WO 2010 / 000720. Further information regarding tableting can be found in Handbook of Powder Technology, Chapter 16: Tabletting, K. Pitt and C. Sinka, Vol 11, 2007, pp. 735-778.

[0122] Advantageously, the tableting operation is carried out as described in WO 2005 / 030393, DE 10 2008 040093, DE 10 2008 040094 and WO 2007 / 017431. The ambient temperature of the tablet press is usually 25° C. The particle size of the precursor composition to be compacted (of the finely divided homogeneous dry mixture), optionally as a result of prior coarsening by compaction, is suitably in the range of 100 to 2000 μm, preferably 150 to 1500 μm, more preferably 400 to 1250 μm, or 400 to 1000 μm, or 400 to 800 μm (forming aids admixed before compaction are not taken into account here).

[0123] The desired geometric shape of the compact obtained in the process of the present invention is not limited, as is the molding apparatus used for consolidation or the molding method employed therein.

[0124] A preferred ring shape (the geometric shapes of the uncalcined green body and the shaped unsupported catalyst body resulting from calcination are usually essentially the same) is a 5 mm × 5 mm × 2 mm (outer diameter × height (length) × inner diameter) geometry. This is because a fixed catalyst bed composed of rings of this geometry results in a particularly low pressure drop for the reactant gas mixture flowing through the fixed catalyst bed (particularly in reactor tubes with an inner diameter of 22 mm to 30 mm). A low pressure drop is particularly advantageous when the partial oxidation catalyzed by the fixed catalyst bed is operated at a high space velocity of the reactant gas mixture over the fixed catalyst bed (i.e., a high flow rate of the reactant gas mixture through the fixed catalyst bed). Another preferred ring shape (which has advantageous bulk properties, particularly in reactor tubes with a relatively small inner diameter (e.g., 20 mm)) is a 5 mm × 3 mm × 2 mm (outer diameter × height (length) × inner diameter) geometry. Useful geometries are, of course, those disclosed and recommended in WO 02 / 062737 and WO 2015 / 067656.

[0125] In particular in the case of annular shaped precursors (regardless of their shape, shaped precursors are also referred to in the literature as green bodies), the shaped consolidation advantageously leads to a lateral crushing strength SDF of the resulting shaped body (see DE 10 2008 040093 A1, DE 10 2008 040094 A1 and WO 2005 / 030393 A1). v However, 5 N≦SDF v ≦100 N, preferably 8 N≦SDF v ≦80 N, more preferably 12 N≦SDF v It should be performed so as to satisfy the relationship ≦50 N.

[0126] The experimental determination of the lateral crushing strength is carried out as described in documents WO 2005 / 030393 and WO 2007 / 017431. It will be appreciated that ring-shaped green bodies as recommended by DE 10 2008 040093 A1 are very particularly preferred in accordance with the invention. In the described manufacturing processes for the green bodies of the present invention, the end faces of the annular or ring-shaped bodies may either be flat (both or only one of the two end faces) or outwardly (convexly) domed (curved) (see in particular DE 10 2007 004961 A1, EP 0 184 790 A1, DE 10 2008 040093 A1 (e.g., paragraph

[0032] thereof) and DE 10 2008 04009 A1 (e.g., paragraph

[0074] thereof), as well as the embodiments described in individual form therein). In determining / specifying the height of such geometrically shaped bodies, such convex domes (curvatures) are generally not taken into account herein. Rings or ring-shaped bodies with convex (curved) end faces (preferably both end faces have the same curvature) are advantageous in that a fixed catalyst bed in a ring or ring-shaped body with convex (curved) end faces (otherwise identical in geometry) results in a lower pressure drop of the reaction gas mixture flowing through the fixed catalyst bed than a fixed catalyst bed in a ring or ring-shaped body with flat end faces (particularly in the case of a fixed catalyst bed in a reaction tube). This is particularly true when the ring shape is 5 mm x 5 mm x 2 mm (outer diameter x height (length) x inner diameter). The radius of curvature of such a convex shape is generally 0.4 to 5 times (e.g., 0.8 to 4 times, 1.2 to 3 times, or 1.6 to 2.6 times) the cylindrical outer diameter of the catalyst ring. As mentioned above, a fixed catalyst bed with a lower pressure drop is advantageous when the partial oxidation catalyzed by the fixed catalyst bed is operated at a high space velocity of the reaction gas mixture over the fixed catalyst bed (i.e., a high flow rate of the reaction gas mixture through the fixed catalyst bed).

[0127] A particularly advantageous ring-shaped body obtained by compacting the finely divided precursor composition (finely divided homogeneous dry mixture) satisfies the condition of height (length) / outer diameter (H / E) = 0.3 to 1.5 or 1.2. More preferably, H / E = 0.5 to 1.1 or 1.0. Furthermore, a ratio I / E (where I is the inner diameter of the ring shape) of 0.3 to 1.5, preferably 0.6 to 1.1, is preferred for the annular or ring-shaped green body of the present invention.

[0128] The aforementioned ring shapes are particularly advantageous when they simultaneously have one of the advantageous H / E ratios and one of the advantageous I / E ratios. Such possible combinations are, for example, H / E = 0.3 to 1.5 or 1.2 and I / E = 0.3 to 1.5 or 0.6 to 1.1. Alternatively, H / E may be 0.5 to 1.1 or 1.0, and I / E may simultaneously be 0.3 to 1.5 or 0.6 to 1.1. Furthermore, it is preferred for the relevant ring shapes if H is 2 to 7 mm, preferably 2 to 6 mm or 3 to 6 mm. It is also advantageous if E in the ring is 4 to 8 mm, preferably 4 to 6 mm. The preferred wall thickness of the ring shape is 1 to 2 mm or 1.5 mm.

[0129] Thus, possible ring shapes of the present invention are (E 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 5 mm x 3 mm x 2.5 mm, or 5.5 mm x 5.5 mm x 2.5 mm, or 5.5 mm x 5.5 mm x 3 mm, or 5 mm x 3 mm 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 6.5 mm x 3 mm x 4.5 mm, or 7 mm x 3 mm x 5 mm, or 7 mm x 7 mm x 3 mm, or 7 mm x 3 mm x 4 mm, or 7 mm x 7 mm x 4 mm.

[0130] All figures of specific surface areas of solids in this specification relate to measurements according to DIN 66131 (Determination of the specific surface area of ​​solids by gas adsorption (N2) according to Brunauer-Emmett-Teller (BET)) unless otherwise stated.

[0131] All figures herein relating to total pore volumes and pore diameter distributions over these total pore volumes relate to determination by the method of mercury porosimetry (evaluation according to the Washburn equation using a contact angle of mercury of 140° and a surface tension of mercury of 480 mN / m = 480 dyn / cm) using an Auto Pore V 9600 system (MicroActive Interactive Dara Analysis Software) from Micromeritics GmbH, D-52072 Aachen (range: 0.1 to 61 000 psi) at 23°C.

[0132] Advantageously, according to the invention, the shaped precursor has a minimal residual moisture content, which is particularly true when the intimate mixing of the various sources of elemental components other than oxygen is carried out in wet form (especially when the aqueous mixture M is formed).

[0133] The residual moisture content of advantageous green bodies preferably has a value of not more than 10% (by weight), better not more than 8% (by weight), even better not more than 6% (by weight), and at most not more than 4% (by weight) or not more than 2% (by weight) (the residual moisture content can be determined (for example with the aid of a Computrac MAX 5000 XL from Arizona Instruments) as described in "Die Bibliothek der Technik" [The Library of Technology], volume 229, "Thermogravimetrische Materialfeuchtebestimmung", Grundlagen und praktische Anwendungen ["Thermogravimetric Determination of Material Moisture Content", Basics and Practical Applications], Horst Nagel, verlag moderne industrie).

[0134] If the green body is derived from an aqueous mixture M (so that its residual moisture content consists of water), the residual moisture content is determined appropriately for the intended application using a microwave (e.g., a BERTHOLD TECHNOLOGIES LB 456 microwave system).

[0135] In this procedure, microwaves irradiate the material being tested at very low power (0.1 mW) (the material undergoes essentially no temperature change as a result of the relatively low power). As a result, the material components become polarized to different degrees. In response, the microwaves lose speed and energy. The influence of water molecules here is significantly greater than that of other components, allowing for selective determination of the residual water content. This is because, due to their size and dipole capacitance, water molecules have a particularly good ability to follow electromagnetic alternating fields in the microwave frequency range by dipole alignment. In doing so, they absorb energy and alter the electromagnetic alternating field due to their electrical properties. This electric field attenuation and field modification are the basis of the measurement principle. For example, it is possible to establish a weak microwave field across the sensor area of ​​a planar sensor and permanently analyze the resonant frequency of the sensor system by scanning the microwave frequency. As a water-containing test material moves across the sensor, there is a shift in its resonant frequency and a decrease in amplitude. As the amount of water increases, i.e., as the bulk density of the test material increases, both the attenuation and the resonant frequency shift increase. However, the ratio of the frequency and attenuation shifts is a density-independent measure of water content and is therefore important for moisture content measurement. This ratio forms the so-called microwave moisture measurement, which represents the total moisture content. Because the microwave resonance method is an indirect moisture measurement method, calibration is required. In such a calibration measurement, a sensor is used to measure a material sample with a defined moisture content. The relationship between the microwave moisture measurement and the corresponding defined absolute material moisture content forms the calibration of the measurement system. Measurement accuracy is typically ±0.1% moisture content (e.g., the moisture content of water can be determined using a Sartorius PMD300PA online moisture analyzer).

[0136] Against this background, spray drying of the wet (eg aqueous) mixture M should already be carried out so that the resulting spray powder has a minimal residual moisture content.

[0137] The green bodies should be stored as far as possible, taking into account the embodiment just addressed, to the exclusion of ambient air (with its humidity) (preferably under anhydrous inert gas or under pre-dried air or in an airtight container until firing is carried out).

[0138] Forming / shaping and storage of the micronized homogeneous dry mixture is advantageously carried out with the exclusion of ambient air (with atmospheric humidity) (for example under an N2 atmosphere).

[0139] The green body is usually fired at a temperature (firing temperature) that reaches or generally exceeds at least 350°C. However, a temperature of 650°C is usually not exceeded during the firing process (the term "firing temperature" in this specification means the temperature present in the fired material (which advantageously has a very uniform (uniform) firing temperature, which also applies correspondingly to other firing conditions). Advantageously, a temperature of 600°C, preferably a temperature of 570°C, and often a temperature of 550°C is not exceeded during the firing process. Furthermore, a temperature of 380°C, advantageously a temperature of 400°C, particularly advantageously a temperature of 420°C, and most preferably a temperature of 440°C is exceeded during the firing process. The firing process can also be subdivided into several sections over its duration.

[0140] Advantageously, prior to calcination, a thermal pretreatment is carried out at a temperature between 120°C and 350°C, preferably between 150°C and 320°C, more preferably between 170°C and 290°C. Suitably for the application purposes, such a thermal pretreatment is carried out until the components present in the composition to be subjected to the thermal treatment and which are broken down into gaseous compounds under the conditions of the thermal treatment are largely (preferably completely) decomposed to give gaseous compounds (the time taken for this may be, for example, from 3 to 15 hours, often 4 to 10 hours or 5 to 8 hours). This generally means that, firstly, the molar amount of cations other than metal ions present in the composition to be subsequently calcined, based on the total molar amount of cations present, is 20 mol% or less (preferably 10 mol% or less), and secondly, the molar amount of O ions present in the same composition, based on the total molar amount of anions present, is 10 mol% or less. 2-Similarly, the molar amount of anions other than the above is 20 mol % or less (preferably 10 mol % or less).

[0141] Therefore, the preferred temperature window for the final firing temperature is within a temperature range of 400 to 600°C, or preferably within a temperature range of 420 to 570°C, or more preferably within a temperature range of 450 to 550°C.

[0142] The total calcination time generally exceeds 0.5 hours, frequently exceeding 2 hours. Calcination usually does not exceed a processing time of 45 or 30 hours. The total calcination time is often less than 25 hours. As a rule, shorter calcination times are generally sufficient at higher calcination temperatures than at lower calcination temperatures. In one advantageous calcination embodiment according to the present invention, the calcination time does not exceed 550°C, and in the temperature window of 430°C to 550°C, the calcination time extends from more than 4 hours to 25 hours.

[0143] The overall heat treatment (including the destruction phase) of the precursor composition (e.g., the green body) can be carried out under either an inert gas or oxidizing atmosphere, such as air (or another mixture of an inert gas and molecular oxygen), and a reducing atmosphere (e.g., a mixture of an inert gas, NH3, CO and / or H2, or methane). The heat treatment can, of course, also be carried out under reduced pressure. The atmosphere can also be changed over the course of the heat treatment.

[0144] The heat treatment (especially the calcination phase) is preferably carried out in an oxidizing atmosphere. This atmosphere is suitably composed mainly of static or (preferably) moving air (more preferably, an air stream passes through the composition (calcined material) subjected to the heat treatment). However, the oxidizing atmosphere may also consist of a stationary or moving mixture of, for example, 25% (by volume) N2 and 75% (by volume) air, or 50% (by volume) N2 and 50% (by volume) air, or 75% (by volume) N2 and 25% (by volume) air (a treatment atmosphere consisting of 100% (by volume) N2 is also possible).

[0145] In principle, the heat treatment (e.g., calcination) of the precursor composition (e.g., the green body) can be carried out in a wide variety of different oven types, such as a heatable air circulation chamber (air circulation oven, e.g., air circulation shaft oven), a staged oven, a rotary oven, a belt calender, or a shaft oven. Advantageously, according to the present invention, the heat treatment (e.g., calcination) is carried out in a belt calender apparatus as recommended by DE 100 46 957 A1 and WO 02 / 24620. The formation of hot spots within the material being treated (the calcined material) is substantially prevented here, in that an increased volume flow of the calcination atmosphere is conveyed through the calcined material on a gas-permeable conveyor belt carrying the calcined material with the aid of a ventilation system (which ensures a substantial uniformity of the calcination temperature within the calcined material).

[0146] In the heat treatment of the precursor composition (e.g., the green body) carried out as described, the shaping aids used can be stored in the resulting shaped catalyst body or can at least partially escape therefrom in gaseous form as a result of thermal and / or chemical decomposition, resulting in gaseous compounds (e.g., CO, CO). The shaping aids remaining in the shaped catalyst body have essentially exclusively a diluting effect on the active composition during its catalytic use. In principle, heat treatment in this regard can be carried out as described in U.S. Patent Application Publication No. 2005 / 0131253.

[0147] Typically, the side crush strength of the annular shaped unsupported catalyst bodies obtained as described according to the present invention is 4-16 N, often 5-14 N or 6-12 N.

[0148] The specific (BET) surface area of ​​the shaped unsupported catalyst bodies is advantageously between 2 and 20 m 2 / g or 15 m 2 / g, preferably 3 to 10 m 2 / g, more preferably 4 to 8 m 2 / g. Advantageously, according to the invention, the corresponding total pore volume (mercury porosimetry) is between 0.33 and 0.60 cm 3 / g, preferably 0.36 to 0.54 cm 3 / g, more preferably 0.38 to 0.50 cm 3 / g range.

[0149] Plot pore diameter in μm on the horizontal axis and cm on the vertical axis 3 / g of total pore volume relative to the respective pore diameter cm 3 When the logarithm of the differential contribution of pores per pore volume of 0.1 μm or less is plotted, the shaped unsupported catalyst bodies particularly preferred according to the invention generally exhibit an essentially unimodal distribution (having only one significant maximum). 3 The result is particularly good overall target product selectivity (e.g., in the case of heterogeneously catalyzed partial oxidation of propene to acrolein and / or acrylic acid) when the contribution of such relatively narrow pores to the total pore volume is 0.05 cm 3 / g, an increase in the calcination time and / or calcination temperature can result in a decrease of this contribution, which is advantageous according to the invention.

[0150] Furthermore, to enhance the overall target product selectivity, it has been found to be advantageous if the contribution of pores having a pore radius in the range of 0.1 to 1 μm to the total pore volume is 85% to 99% (volume basis), advantageously 87% to 97% (volume basis), more preferably 89% to 95% (volume basis), based on the total pore volume.

[0151] It will be understood that the shaped unsupported catalyst body can also be diluted with an inert material for use in catalysis of heterogeneously catalyzed partial gas-phase oxidation. Suitable inert diluent materials of this type include elemental oxides, such as aluminum oxide, silicon dioxide, thorium dioxide, and zirconium dioxide, that are calcined at high temperatures and therefore have a relatively low level of porosity. Alternatively, finely divided silicon carbide or finely divided silicates, such as magnesium silicate and aluminum silicate or steatite, can be used for the above-mentioned purposes. Advantageously, for application purposes, the procedure here is, for example, to grind the calcined active composition into a finely divided powder. This is then mixed with a finely divided diluent material, and the resulting mixed powder is formed into a geometrically shaped body (preferably by tableting) using the molding method proposed in this document. The latter is then converted into the corresponding shaped unsupported catalyst body by calcining again. However, the finely divided inert diluent material may, of course, already be incorporated into the wet (e.g., aqueous) mixture M, for example, before drying. Furthermore, the finely divided inert diluent material can be incorporated into the finely divided dry mixture. However, such a procedure is less preferred according to the present invention.

[0152] A particular feature of the shaped unsupported catalyst bodies produced by the advantageous production method described is that they are essentially free of localized centers of elemental oxides. Instead, these elements are very substantially part of a complex mixed oxomolybdate containing Bi, Fe, and Mo. This has been found to be advantageous with respect to the objective of the present invention of minimizing the complete combustion of undesired organic reactant gas mixture components during the associated heterogeneously catalyzed partial oxidation.

[0153] Otherwise, the preparation procedure for unsupported catalysts is suitable as in WO 2010 / 066645 in terms of maximum efficiency of material utilization.

[0154] The shaped unsupported catalyst bodies of the invention are not only suitable for catalysis of the heterogeneously catalyzed partial oxidation of propene to acrolein, but are also generally suitable for catalysis of the heterogeneously catalyzed partial gas-phase oxidation of alkanes, alkanols, alkenes and / or alkenals having 3 to 6 carbon atoms (partial oxidation is understood in this context to mean, in particular, a transformation of an organic compound with the reactive participation of molecular oxygen, in which, after the reaction is completed, the organic compound that is partially oxidized contains at least one oxygen atom in a chemically bound form than before the partial oxidation was carried out). The term "partial oxidation" in this context alternatively includes oxidative dehydrogenation and partial ammoxidation, i.e., partial oxidation in the presence of ammonia.

[0155] The shaped unsupported catalyst bodies of the present invention are particularly suitable for catalyzing the heterogeneously catalyzed partial gas-phase oxidation of propene to acrolein and isobutene to methacrolein, and for catalyzing the heterogeneously catalyzed partial gas-phase ammoxidation of propene to acrylonitrile and isobutene to methacrylonitrile.

[0156] As already mentioned, the heterogeneously catalyzed partial gas-phase oxidation of propene (isobutene and / or tert-butanol) to acrolein (methacrolein) forms the first stage of a two-stage heterogeneously catalyzed partial gas-phase oxidation of propene (isobutene and / or tert-butanol) to acrylic acid (methacrylic acid), as described by way of example in WO 2006 / 42459.

[0157] Thus, the formation of (meth)acrylic acid by-product associated with the heterogeneously catalyzed partial gas-phase oxidation of propene (isobutene) to acrolein (methacrolein) is generally undesirable and is usually covered by the desired formation of valuable products.

[0158] The above is particularly true for the annular shaped unsupported catalyst bodies of the present invention.

[0159] Heterogeneously catalyzed partial oxidations, in particular the partial oxidation of propene to acrolein, are described, for example, in the literature for similar catalysts, in DE 10 2007 004961 A1, WO 02 / 49757 A1, WO 02 / 24620 A1, DE 10 2008 040093 A1, WO 2005 / 030393 A1, EP 0 575 897 A1, WO 2007 / 082827 A1, WO 2005 / 113127 A1, WO 2005 / 047224 A1, WO 2005 / 042459 A1, WO 2007 / 017431 A1, DE 10 2008 A1, WO 2008 042060, WO 2008 / 087116, DE 10 2010 048405, DE 10 2009 047291, DE 10 2008 042064, DE 10 2008 042061, WO 2015 / 067656 and DE 10 2008 040094 (more particularly, it is possible to proceed herein in a manner corresponding to that of the exemplary embodiments of these documents).

[0160] However, the shaped unsupported catalyst bodies (in particular annular shaped unsupported catalyst bodies) obtainable as described are also advantageous when the space velocity of propene, isobutene and / or tert-butanol (or their methyl ethers) present in the reaction gas input mixture at the time of catalyst charging of the reactor is greater than or equal to 130 L(STP) / L catalyst charge h, or greater than or equal to 140 L(STP) / L h, or greater than or equal to 150 L(STP) / L h, or greater than or equal to 160 L(STP) / L h (upstream and / or downstream beds of pure inert material are not considered to form part of the catalyst charge in the context of the space velocity here; the volume of the catalyst charge (of a fixed catalyst bed) is concomitantly the bed volume thereof in the reactor). Typically, the space velocity of the catalyst packing is 600 L(STP) / L·h or less, often 500 L(STP) / L·h or less, often 400 L(STP) / L·h or less or 350 L(STP) / L·h or less. Space velocities in the range of 160 L(STP) / L·h or more or 180 L(STP) / L·h to 300 L(STP) / L·h or less or 250 L(STP) / L·h or less or 200 L(STP) / L·h or less are particularly suitable.

[0161] In the present specification, the space velocity of a reaction gas input mixture in a fixed catalyst bed is understood to mean the standard liter amount of reaction gas input mixture (= L(STP); the volume in liters occupied by the corresponding amount of reaction gas input mixture under standard conditions of 0° C. and 1 atmosphere (1.01 bar)) fed to the fixed catalyst bed per hour, based on the volume of the bed (not including the bed section of pure inert material), i.e., on the bed volume (->unit = L(STP) / L·h). In the present specification, units of standard volume, such as L(STP) or m 3 (STP) always (unless otherwise stated) refers to standard conditions of 0° C. and 1 atmosphere (1.01 bar).

[0162] Space velocity may also be based on only one component of the reaction gas input mixture (e.g., only the organic starting compound to be partially oxidized), in which case it is the volume of this component (e.g., the organic starting compound to be partially oxidized) fed to the fixed catalyst bed (catalyst packing of the reactor) per hour, based on the volume of that bed.

[0163] The shaped unsupported catalyst bodies (for example in annular form) obtainable according to the invention can of course also be operated in an advantageous manner according to the invention as catalysts for the partial oxidation of propene to acrolein or of isobutene and / or tert-butanol (or its methyl ethers) to methacrolein at space velocities of the partially oxidized starting compounds at a catalyst loading of 130 L(STP) / L·h or less, or 120 L(STP) / L·h or less, or 110 L(STP) / L·h or less, or 100 L(STP) / L·h or less, or 90 L(STP) / L·h. Generally, however, this space velocity will be at a value of at least 20 L(STP) / L·h, or at least 30 L(STP) / L·h, or at least 40 L(STP) / L·h, or at least 50 L(STP) / L·h, or at least 60 L(STP) / L·h, or at least 70 L(STP) / L·h, or at least 80 L(STP) / L·h.

[0164] In principle, the space velocity of the partially oxidized starting compounds (propene, isobutene and / or tert-butanol (or its methyl ether)) during the catalyst loading of the reactor (on a fixed catalyst bed) is controlled by two adjusting screws: a) the space velocity of the reaction gas input mixture (the reaction gas mixture fed to the fixed catalyst bed) at the time of catalyst loading, and / or b) the content of partially oxidized starting compounds in the reaction gas input mixture can be adjusted via

[0165] The shaped unsupported catalyst bodies (e.g. ring-shaped) obtainable according to the invention are also suitable, in particular for space velocities of the organic compounds to be partially oxidized at catalyst loadings above 130 L(STP) / L·h, when the space velocity is adjusted via the adjusting screw a) mentioned above.

[0166] Typically, for example, the propene content (isobutene content or tert-butanol content (or methyl ether content)) in the reaction gas input mixture is 4% to 10% (by volume), often 5% to 9% (by volume), or 5.5% to 8.0% (by volume), or 6.0% to 7.5% (by volume) (in each case based on the total volume (flow rate) of the reaction gas input mixture flowing towards the fixed catalyst bed), essentially independent of the space velocity at the catalyst loading.

[0167] Frequently, gas phase partial oxidation processes catalyzed by the shaped unsupported catalyst bodies (e.g., ring-shaped) of the present invention obtained as described are carried out at a volume ratio (essentially independent of space velocity) of the (organic) compound to be partially oxidized (e.g., propene):oxygen:inert gas (including steam) in the reaction gas input mixture of 1:(1.0-3.0):(5-25), preferably 1:(1.5-2.3):(10-20).

[0168] Inert gases are understood here to mean gases which, in the course of the partial oxidation, remain chemically unchanged to an extent of at least 95 mol%, preferably to an extent of at least 98 mol%, in one pass of the reaction gas mixture through the catalyst bed.

[0169] In the above-mentioned reaction gas input mixture, the inert gas may be present to the extent of 20% or more by volume, or to the extent of 30% or more by volume, or to the extent of 40% or more by volume, or To the extent of 50% (by volume) or more, or to the extent of 60% (by volume) or more, or to the extent of 70% (by volume) or more, or to the extent of 80% (by volume) or more, or It may consist of molecular nitrogen to an extent of 90% (by volume) or more, or to an extent of 95% (by volume) or more.

[0170] However, at higher space velocities of the organic compounds to be partially oxidized during catalyst loading of the reactor (e.g., 150 L(STP) / L·h or higher), the additional use of inert diluent gases with high molar heat and / or thermal conductivity, such as propane, ethane, methane, pentane, butane, CO2, CO, steam, and / or noble gases, is recommended (but not required) for the reaction gas input mixture. In general, these inert gases and their mixtures can also be used at lower space velocities of the organic compounds to be partially oxidized during catalyst loading. Cycle gas can also be used partially as a diluent gas. Cycle gas is understood to mean the tail gas remaining when the target compounds are essentially selectively separated from the product mixture of partial oxidation. It should be taken into account here that the partial oxidation to acrolein or methacrolein using the shaped unsupported catalyst bodies, for example in ring form, obtainable according to the invention may be only the first stage of a two-stage partial oxidation to acrylic acid or methacrylic acid as the actual target compound, with the result that cycle gas is usually only formed after the second stage (typical cycle gas compositions for the heterogeneously catalyzed partial oxidation of propene to acrolein and / or acrylic acid are shown in DE-A 102 32 482, paragraphs

[0063] and

[0075] ). In the context of such two-stage partial oxidations, the product gas mixture from the first stage is generally fed directly to the second partial oxidation stage, optionally after cooling and / or secondary oxygen addition (generally in the form of air).

[0171] For the partial oxidation of propene to acrolein, using the shaped unsupported catalyst bodies of the invention (for example in annular form) obtainable as described, the typical composition of the reaction gas input mixture measured at the reactor inlet (irrespective of the selected space velocity) can comprise, for example, the following components: 6% to 6.5% by volume of propene, 1% to 3.5% by volume of H2O, 0.8% to 1.7% by volume of CO x , 0.015% to 0.04% by volume of acrolein, 9.4% to 12.3% by volume of oxygen, and Molecular nitrogen as the balance to make up 100% by volume; or 5.6% by volume of propene, 1.4% by volume of H2O, 1.2% by volume CO x , 10.2% by volume of oxygen, and Molecular nitrogen as the balance to make up 100% by volume. The former composition is particularly suitable in a fixed catalyst bed at propene space velocities of 130 L(STP) / L·h or more, and the latter composition is particularly suitable at propene space velocities of less than 130 L(STP) / L·h, in particular less than 100 L(STP) / L·h (e.g., for the onset of partial oxidation).

[0172] Alternatively, for the partial oxidation of propene to acrolein according to the invention, it is also possible to use a reaction gas input mixture of a composition according to Example 1 of EP-A-0 990 636, or according to Example 2 of EP-A-0 990 636, or according to Example 3 of EP-A-1 106 598 A2, or according to Example 26 of EP-A-1 106 598 A2, or according to Example 53 of EP-A-1 106 598 A2, or according to the examples of WO 2021 / 013640.

[0173] The shaped unsupported catalyst bodies of the invention, for example in the form of rings, which can be obtained as described, are also suitable for the process of DE-A 102 46 119 or DE-A 102 45 585.

[0174] When using the shaped unsupported catalyst bodies of the invention (e.g. ring-shaped) obtainable as described, the reaction temperature of the heterogeneously catalyzed partial oxidation of propene to acrolein of the invention is often 300 to 450° C., or 400° C., or 380° C. A particularly preferred reaction temperature window is 305 to 345° C. The same applies to methacrolein as the target compound.

[0175] The reaction pressure for the above-mentioned partial oxidation is generally from 0.5 to 4 or 3 bar, or preferably from 1.1 or 1.5 to 4 or 3 bar (all references herein are to absolute pressure unless otherwise stated).

[0176] The total space velocity of the reaction gas input mixture during catalyst loading in the above-mentioned partial oxidation of the present invention typically ranges from 1000 to 10 000 L(STP) / L·h, usually from 1500 to 5000 L(STP) / L·h, and often from 2000 to 4000 L(STP) / L·h.

[0177] Useful propenes for use in the reaction gas input mixture are, in particular, polymer-grade propene and chemical-grade propene, as described, for example, in WO 2004 / 007405.

[0178] The oxygen source used is usually air (optionally together with cycle gas).

[0179] Partial oxidation using the shaped unsupported catalyst bodies of the invention (e.g. ring-shaped unsupported catalyst bodies) obtainable as described above can be carried out in the simplest case in a single-zone, multi-catalyst tubular fixed-bed reactor, as described, for example, in DE-A-44 31 957, EP-A-0 700 714 and EP-A-0 700 893.

[0180] Typically, in the shell-and-tube reactors described above, the catalyst tubes are made of ferritic steel and typically have a wall thickness of 1 to 3 mm. Their inner diameters are generally 20 to 30 mm, often 21 to 26 mm. Typical catalyst tube lengths are, for example, 3.50 m, 4.00 m, or 4.50 m. The number of catalyst tubes contained in a shell-and-tube vessel is suitably at least 1,000, preferably at least 5,000. In many cases, the number of catalyst tubes contained in a reactor vessel is 15,000 to 40,000. Shell-and-tube reactors with more than 45,000 catalyst tubes are usually exceptional. Within the vessel, the catalyst tubes are usually arranged in a uniform distribution, which is appropriately selected so that the distance between the central internal axes of adjacent catalyst tubes (called the catalyst tube pitch) is 35 to 45 mm (see EP 0 468 290).

[0181] Alternatively, partial oxidation can be carried out in a multi-zone "two-zone" multi-catalyst tube fixed-bed reactor, as recommended by German Patent Applications Nos. 199 10 506, 103 13 213, 103 13 208, and EP 1 106 598, at an increased space velocity of the organic compound to be partially oxidized, particularly at the catalyst loading of the multi-catalyst tube reactor. Typical catalyst tube lengths for two-zone multi-catalyst tube fixed-bed reactors are, for example, 3.50 m, 4.00 m, or 4.50 m. Everything else is essentially as described for the one-zone multi-catalyst tube fixed-bed reactor. In each temperature control zone of the one-zone or multi-zone multi-catalyst tube fixed-bed reactor (a one-zone multi-catalyst tube fixed-bed reactor has only one temperature control zone), a heat exchange medium is conducted around the catalyst tubes in which the catalyst loading (fixed catalyst bed) is located. Suitable examples of heat exchange media are melts of salts such as potassium nitrate, potassium nitrite, sodium nitrite and / or sodium nitrate, or melts of low melting point metals such as sodium, mercury and alloys of different metals. The flow rate of the heat exchange media within each temperature control zone is generally selected so that the temperature of the heat exchange media increases by 0-15°C, often 1-10°C, or 2-8°C, or 3-6°C from the point of entry into the temperature control zone to the point of exit from the temperature control zone.

[0182] Over the course of each temperature control zone, the inlet temperature of the heat exchange medium, which may be guided in cocurrent or countercurrent to the reaction gas mixture, is preferably selected as recommended in documents EP-A-1 106 598, DE-A-199 48 523, DE-A-199 48 248, DE-A-103 13 209, EP-A-0 700 714, DE-A-103 13 208, DE-A-103 13 213, WO 00 / 53557, WO 00 / 53558, WO 01 / 36364, WO 00 / 53557 and the other documents cited as prior art therein. Within the temperature control zone, the heat exchange medium is preferably guided in a serpentine manner. The difference between the maximum and minimum temperatures of the heat exchange medium in the temperature control zone should be taken into account over the length section of the temperature control zone where the catalytically active section of the fixed catalyst bed (not a purely inert bed) is present, and is advantageously between 0°C and 5°C (this difference is preferably small). Generally, a multi-catalyst tube fixed-bed reactor also has a heat tube for determining the temperature of the reaction gas in the catalyst bed (the heat tube and the reaction tube are filled with the same fixed bed). In an appropriate manner, the inner diameter of the heat tube and the diameter of the receiving well (thermowell) for the thermocouple, centered therein and extending parallel to the longitudinal axis of the heat tube, are selected so that the ratio of the volume generating the reaction heat to the heat removal surface area of ​​the heat tube and the work tube are the same or slightly different.

[0183] The pressure drop in the working tube and the heat tube should be the same based on the same GHSV (= volumetric flow intensity of the reaction gas mixture entering the tube divided by the bed volume of the fixed catalyst bed present in the tube). Compensation of the pressure drop in the heat tube can be achieved, for example, by adding catalyst spall to shaped unsupported catalyst bodies. This compensation is carried out appropriately uniformly over the entire length of the heat tube. For the rest, the filling of the heat tube can be configured as described in EP-A-0 873 783.

[0184] As already mentioned, to provide the catalyst loading in the catalyst tubes, it is possible to use only the shaped unsupported catalyst bodies (e.g., in annular form) obtained as described above, or, for example, a substantially homogeneous mixture of the shaped unsupported catalyst bodies (e.g., in annular form) obtained as described above with a shaped body that does not contain an active component and is essentially inert with respect to the heterogeneously catalyzed partial gas-phase oxidation. Materials useful for such inert shaped bodies include, for example, porous or non-porous aluminum oxide, silicon dioxide, zirconium dioxide, silicon carbide, silicates such as magnesium silicate or aluminum silicate, and / or steatite (e.g., type C220 from CeramTec, Germany).

[0185] The geometric shape of such inert shaped diluent bodies is as desired. This means that they may be, for example, spheres, polygons, solid cylinders, as in the case of ring-shaped shaped catalyst bodies, e.g., rings. Often, the selected inert shaped diluent bodies are of a geometric shape corresponding to that of the shaped catalyst bodies with which they are diluted. However, the geometric shape of the shaped catalyst bodies may be varied along the catalyst packing, or shaped catalyst bodies of different geometric shapes may be used in a substantially uniform blend. In a less preferred procedure, the active composition of the shaped catalyst bodies may also be varied along the catalyst packing.

[0186] Very generally, the catalyst loading is advantageously configured so that the volume-specific activity (i.e., activity normalized to units of volume) remains constant or increases (continuously, abruptly, or in steps) in the flow direction of the reaction gas mixture.

[0187] A reduction in volume-specific activity can be achieved in a simple manner, for example, by uniformly diluting a base amount of shaped, unsupported catalyst bodies (e.g., ring-shaped) uniformly produced according to the present invention with an inert, shaped diluent body. The higher the proportion of shaped diluent body selected, the lower the amount of active composition or catalytic activity present in a specific volume of packing. Reduction can also be achieved by changing the geometry of the shaped, unsupported catalyst bodies obtainable according to the present invention so that a lower amount of active composition is present per unit of inner reactor tube volume.

[0188] In the case of heterogeneously catalyzed gas-phase partial oxidation using shaped unsupported catalyst bodies (e.g., ring-shaped) obtainable as described, the catalyst packing is preferably composed uniformly over its entire length with only one type of shaped unsupported catalyst body, or is composed as follows: At the reactor inlet, an essentially homogeneous mixture of shaped unsupported catalyst bodies (e.g., ring-shaped) and inert shaped diluent bodies (both preferably having essentially the same geometric shape) is arranged over a length in each case of 10% to 60% (by weight), preferably 10% to 50% (by weight), more preferably 20% to 40% (by weight), and most preferably 25% to 35% (by weight) of the total length of the catalyst packing (i.e., for example, a length of 0.70 to 1.50 m, preferably 0.90 to 1.20 m), and the weight proportion of the shaped diluent bodies (the bulk densities of the shaped catalyst bodies and the shaped diluent bodies generally differ only slightly) is typically 5% to 40% (by weight), or 10% to 40% (by weight), or 20% to 40% (by weight), or 25% to 35% (by weight). This first packed section is then advantageously followed, to the end of the length of the catalyst packing (i.e., for example, over a length of 1.00 to 3.00 m, or 1.00 to 2.70 m, preferably 1.40 to 3.00 m, or 2.00 to 3.00 m), either by a bed of the same shaped unsupported catalyst bodies (e.g., in annular form) obtained as described above, only slightly diluted (compared to the first section), or, most preferably, by a 100% (undiluted) bed of the same shaped unsupported catalyst bodies (e.g., in annular form) also used in the first section. Of course, it is also possible to choose a constant dilution throughout the packing. It is also possible to fill only the first section with shaped unsupported catalyst bodies (e.g., ring-shaped unsupported catalyst bodies) having a low active composition density based on space occupation, and the second section with shaped unsupported catalyst bodies (e.g., annular unsupported catalyst bodies) obtained according to the present invention having a high active composition density based on space occupation (e.g., 6.5 mm x 3 mm x 4.5 mm [outer diameter x height x inner diameter] for the first section and 5 x 2 x 2 mm [E x H x I] for the second section).

[0189] In the flow direction of the reaction gas mixture upstream of the actual fixed bed catalyst charge, a bed of inert shaped bodies can be provided, which, for example, has the purpose of raising the inlet temperature of the reaction gas mixture to the temperature of the heat exchange medium.

[0190] Furthermore, according to the teachings of the prior art (for example, WO 2012 / 049246), in the case of heterogeneously catalyzed partial oxidation of propene to acrolein (or in the case of heterogeneously catalyzed partial oxidation for the preparation of methacrolein), the catalyst charge of the reactor (especially the fresh catalyst charge) and the process conditions for the catalytic partial oxidation are preferably selected (configured) so that there is no point in the fixed catalyst bed in the partial oxidation operation where the difference between the fixed catalyst bed temperature at this point and the temperature of the heat exchange medium at this level is 120°C or more. Advantageously, however, this temperature difference at all points in the positive direction is 100°C or less (especially 40-100°C), particularly advantageously 90°C or less (especially 50-90°C). However, in principle, this (positive) temperature difference may also be 50°C or less or 40°C or less. Furthermore, this temperature difference is preferably configured such that a 1°C increase in the temperature of the heat exchange medium results in an increase at any point in the fixed catalyst bed of more than 0°C but not more than +9°C, more preferably not more than +7°C, preferably not more than +5°C, more preferably not more than +3°C (see also EP 1 106 598).

[0191] Otherwise, heterogeneously catalyzed partial oxidation for the preparation of acrolein (from propene) or methacrolein (from the C4 precursor compounds mentioned in this document) with an annular-shaped unsupported catalyst body produced according to the invention can be advantageously carried out in a manner that fully corresponds to the details of WO 2015 / 067656.

[0192] In the case of partial oxidation for the preparation of acrolein or methacrolein, which is carried out using the shaped unsupported catalyst bodies (e.g., ring-shaped) obtainable as described catalysts, the catalyst packing, the starting reaction gas mixture, the space velocity, and the reaction temperature are generally selected so as to achieve a conversion of at least 90 mol%, or at least 92 mol%, preferably at least 93 mol%, or at least 94 mol%, or at least 95 mol%, or at least 97 mol%, but usually not more than 99 mol%, of the organic compound to be partially oxidized (propene, isobutene, tert-butanol, or its methyl ether) in one pass of the reaction gas mixture through the catalyst packing. Here, the selectivity to valuable products (acrolein and acrylic acid combined, or methacrolein and methacrylic acid combined) is usually not less than 80 mol%, or not less than 85 mol%, or not less than 90 mol%.

[0193] Finally, it should be emphasized that the shaped unsupported catalyst bodies of the invention obtained as described above also have advantageous crushing properties in the filling of reactors.

[0194] The start-up of a new catalyst charge (fixed catalyst bed) comprising shaped unsupported catalyst bodies (for example in annular form) obtainable according to the invention can be carried out, for example, as described in DE-A 103 37 788 or DE-A 10 2009 047291.

[0195] The formation of shaped unsupported catalyst bodies obtained according to the present invention can be promoted by conducting it at essentially uniform conversion at high space velocities of the reaction gas input mixture during catalyst loading.

[0196] Otherwise, the unsupported catalysts obtained according to the invention are very generally suitable for the catalysis of the gas-phase partial (amm) oxidation of alkanols, alkanals, alkenes, alkanes and alkenals having 3 to 6 (i.e., 3, 4, 5 or 6) carbon atoms to, for example, olefinically unsaturated aldehydes and / or carboxylic acids and the corresponding nitriles, as well as for the gas-phase catalytic oxidative dehydrogenation of the aforementioned organic compounds containing 3, 4, 5 or 6 carbon atoms.

[0197] The industrial-scale production of the shaped unsupported catalyst bodies of the present invention is suitably carried out in the same manner as described in DE 10 2008 040093 A1 and DE 10 2008 040094 A1 (particularly advantageously as in the exemplary embodiments of these documents).

[0198] Accordingly, the present invention specifically encompasses the following embodiments of the invention: 1. A method for producing a shaped, unsupported catalyst body for the gas-phase oxidation of alkenes and / or alcohols to α,β-unsaturated aldehydes and / or α,β-unsaturated carboxylic acids, the shaped, unsupported catalyst body comprising at least the elements molybdenum, bismuth, iron and cobalt; a) producing an aqueous solution or suspension using in each case at least one source of the elemental components molybdenum, bismuth, iron, cobalt and optionally at least one source of the elemental component nickel, b) the powder P is prepared by drying and optionally grinding the aqueous solution or suspension obtained in a), c) the powder P obtained in b) is, after homogeneous mixing and optionally compaction, optionally with the addition of one or more auxiliaries, compacted into a shaped precursor having a cylindrical structure, d) heat treating the shaped precursor obtained in c) to form a shaped unsupported catalyst body; The pressure in the consolidation of c) is set to a value where the density of the molding precursor is 1.70 to 2.30 g / cm 3 and the density of the shaped precursor is the quotient of the mass and the geometric volume, and d) is selected so that the weight loss during the heat treatment is 25% to 40% (by weight).

[0199] The pressure in the consolidation of 2.c) is set so that the density of the molding precursor is 1.72 to 2.28 g / cm 3 2. The method of embodiment 1, wherein the α-terminal β ...

[0200] The pressure in the consolidation of 3.c) is set to a value where the density of the molding precursor is 1.74 to 2.26 g / cm 3 3. The method of embodiment 1 or 2, wherein:

[0201] The pressure in the consolidation of 4.c) is set to a value where the density of the molding precursor is 1.76 to 2.24 g / cm 3 4. The method of any one of embodiments 1 to 3, wherein:

[0202] The pressure in the consolidation of 5.c) is set to a value where the density of the molding precursor is 1.78 to 2.22 g / cm 3 5. The method of any one of embodiments 1 to 4, wherein:

[0203] The pressure in the consolidation of 6.c) is set to a value where the density of the molding precursor is 1.80 to 2.20 g / cm 3 6. The method of any preceding embodiment, wherein the method is selected to be:

[0204] 7. The method according to any one of the preceding claims, wherein the weight loss in the heat treatment of step d) is between 26% and 39% (by weight).

[0205] 8. The method according to any one of the preceding claims, wherein the weight loss in the heat treatment of step d) is between 27% and 38% (by weight).

[0206] 9. The method according to any one of the preceding claims, wherein the weight loss in the heat treatment of step d) is between 28% and 38% (by weight).

[0207] 10. The method according to any one of the preceding claims, wherein the weight loss in the heat treatment of step d) is between 29% and 37% (by weight).

[0208] 11. The method according to any one of the preceding claims, wherein the weight loss in the heat treatment of step d) is 30% to 35% (by weight).

[0209] 12. Cylindrical structure i) a cylinder with a central circular opening along its length, or ii) a cylindrical body having three uniformly cut-outs in the longitudinal direction and having three uniformly spaced circular openings in the longitudinal direction.

[0210] 13. The method of any of embodiments 1 to 12, wherein the cylindrical structure is a hollow cylinder.

[0211] 14. The method of any one of embodiments 1 to 13, wherein the molybdenum content of the shaped unsupported catalyst body, calculated as MoO3, is 45% to 75% (by weight).

[0212] 15. The method of any one of embodiments 1 to 14, wherein the molybdenum content of the shaped unsupported catalyst body, calculated as MoO3, is 50% to 70% (by weight).

[0213] 16. The method of any one of embodiments 1 to 15, wherein the molybdenum content of the shaped unsupported catalyst body, calculated as MoO3, is 55% to 65% (by weight).

[0214] 17. The method of any one of embodiments 1 to 16, wherein the bismuth content of the shaped unsupported catalyst body, calculated as Bi2O3, is 1% to 20% (by weight).

[0215] 18. The method of any one of embodiments 1 to 17, wherein the bismuth content of the shaped unsupported catalyst body, calculated as Bi2O3, is 2% to 15% (by weight).

[0216] 19. The method of any one of embodiments 1 to 18, wherein the bismuth content of the shaped unsupported catalyst body, calculated as Bi2O3, is 3% to 10% (by weight).

[0217] 20. The method of any one of embodiments 1 to 19, wherein the iron content of the shaped unsupported catalyst body, calculated as Fe2O3, is 2% to 12% (by weight).

[0218] 21. The method of any one of embodiments 1 to 20, wherein the iron content of the shaped unsupported catalyst body, calculated as Fe2O3, is 3% to 11% (by weight).

[0219] 22. The method of any one of embodiments 1 to 21, wherein the iron content of the shaped unsupported catalyst body, calculated as Fe2O3, is 4% to 10% (by weight).

[0220] 23. The method of any one of embodiments 1 to 22, wherein the total cobalt and nickel content of the shaped unsupported catalyst body, calculated as CoO and NiO, is 9% to 30% (by weight).

[0221] 24. The method of any one of embodiments 1 to 23, wherein the total cobalt and nickel content of the shaped unsupported catalyst body, calculated as CoO and NiO, is 12% to 27% (by weight).

[0222] 25. The method of any one of embodiments 1 to 24, wherein the total cobalt and nickel content of the shaped unsupported catalyst body, calculated as CoO and NiO, is 15% to 24% (by weight).

[0223] 26. The method of any one of embodiments 1 to 25, wherein the shaped unsupported catalyst body further comprises elemental potassium and / or silicon.

[0224] 27. A shaped unsupported catalyst body having a cylindrical structure for the gas-phase oxidation of alkenes and / or alcohols to α,β-unsaturated aldehydes and / or α,β-unsaturated carboxylic acids, obtainable by the method according to any one of embodiments 1 to 26, wherein the shaped unsupported catalyst body comprises at least the elements molybdenum, bismuth, iron, and cobalt, and the density of the shaped unsupported catalyst body is 1.20 to 1.70 g / cm.3 The density of the shaped unsupported catalyst body is the quotient of the mass and the geometric volume, and the total pore volume of the shaped unsupported catalyst body is 0.33 to 0.60 cm 3 / g, and the pore volume in the range of 0.1 to 1 μm of the shaped unsupported catalyst body is 85% to 99% of the total pore volume, and the total pore volume and the pore volume in the range of 0.1 to 1 μm are determined by mercury porosimetry.

[0225] 28. The density of the shaped unsupported catalyst body is 1.22 to 1.68 g / cm 3 28. The shaped unsupported catalyst body of embodiment 27, wherein

[0226] 29. The density of the shaped unsupported catalyst body is 1.24 to 1.66 g / cm 3 29. The shaped unsupported catalyst body of embodiment 27 or 28, wherein

[0227] 30. The density of the shaped unsupported catalyst body is 1.26 to 1.64 g / cm 3 30. The shaped unsupported catalyst body of any of embodiments 27 to 29, wherein

[0228] 31. The density of the shaped unsupported catalyst body is 1.28 to 1.62 g / cm 3 31. The shaped unsupported catalyst body of any of embodiments 27 to 30, wherein

[0229] 32. The density of the shaped unsupported catalyst body is 1.30 to 1.60 g / cm 3 32. The shaped unsupported catalyst body of any of embodiments 27 to 31, wherein

[0230] 33. The total pore volume of the molded unsupported catalyst body is 0.34 to 0.58 cm 3 33. The shaped unsupported catalyst body of any of embodiments 27 to 32, wherein:

[0231] 34. The total pore volume of the shaped unsupported catalyst body is 0.35 to 0.56 cm 3 34. The shaped unsupported catalyst body of any of embodiments 27 to 33, wherein:

[0232] 35. The total pore volume of the shaped unsupported catalyst body is 0.36 to 0.54 cm 3 35. The shaped unsupported catalyst body of any of embodiments 27 to 34, wherein:

[0233] 36. The total pore volume of the shaped unsupported catalyst body is 0.37 to 0.52 cm 3 36. The shaped unsupported catalyst body of any of embodiments 27 to 35, wherein:

[0234] 37. The total pore volume of the shaped unsupported catalyst body is 0.38 to 0.50 cm 3 37. The shaped unsupported catalyst body of any of embodiments 27 to 36, wherein:

[0235] 38. The shaped, unsupported catalyst body of any one of embodiments 27 to 37, wherein the pore volume of the shaped, unsupported catalyst body in the range of 0.1 to 1 μm is 86% to 98% of the total pore volume.

[0236] 39. The shaped, unsupported catalyst body of any one of embodiments 27 to 38, wherein the pore volume of the shaped, unsupported catalyst body in the range of 0.1 to 1 μm is 87% to 97% of the total pore volume.

[0237] 40. The shaped, unsupported catalyst body of any of embodiments 27 to 39, wherein the pore volume in the range of 0.1 to 1 μm is 88% to 96% of the total pore volume.

[0238] 41. The shaped, unsupported catalyst body of any one of embodiments 27 to 40, wherein the pore volume of the shaped, unsupported catalyst body in the range of 0.1 to 1 μm is 89% to 95% of the total pore volume.

[0239] 42. Cylindrical structure i) a cylinder with a central circular opening along its length, or ii) a cylindrical body having three uniformly longitudinally spaced circular openings with three uniformly longitudinally spaced notches.

[0240] 43. The shaped unsupported catalyst body according to embodiment 42, wherein the shortest distance between the outer wall of the cylinder and the next opening is 0.75 to 2.5 mm.

[0241] 44. The shaped unsupported catalyst body of embodiment 42 or 43, wherein the shortest distance between the outer wall of the cylinder and the next opening is 0.8 to 2.0 mm.

[0242] 45. The shaped unsupported catalyst body according to any one of embodiments 42 to 44, wherein the shortest distance between the outer wall of the cylinder and the next opening is 1.0 to 1.8 mm.

[0243] 46. ​​The shaped unsupported catalyst body according to any one of embodiments 42 to 45, wherein the shortest distance between the outer wall of the cylinder and the next opening is 1.2 to 1.7 mm.

[0244] 47. The shaped unsupported catalyst body according to any one of embodiments 42 to 46, wherein the shortest distance between the outer wall of the cylinder and the next opening is 1.3 to 1.6 mm.

[0245] 48. The shaped unsupported catalyst body of any of embodiments 27 to 42, wherein the cylindrical structure is a hollow cylinder.

[0246] 49. The shaped unsupported catalyst body of embodiment 48, wherein the wall thickness of the hollow cylinder is 0.75 to 2.5 mm.

[0247] 50. The shaped unsupported catalyst body of embodiment 48 or 49, wherein the wall thickness of the hollow cylinder is 0.8 to 2.0 mm.

[0248] 51. The shaped unsupported catalyst body of any of embodiments 48 to 50, wherein the wall thickness of the hollow cylinder is 1.0 to 1.8 mm.

[0249] 52. The shaped unsupported catalyst body of any of embodiments 48 to 51, wherein the wall thickness of the hollow cylinder is 1.2 to 1.7 mm.

[0250] 53. The shaped unsupported catalyst body of any of embodiments 48 to 52, wherein the wall thickness of the hollow cylinder is 1.3 to 1.6 mm.

[0251] 54. The shaped, unsupported catalyst body of any of embodiments 27 to 53, wherein the shaped, unsupported catalyst body is a multi-element oxide of general formula I. Mo 12 Bi a Fe b Co c Ni d X e Y f Z g O n (I) (In the formula, 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=0.2~2 b=1~4 c=3~9 d=0~4 c+d=4~9.5 e=0.01~0.5 f=0~10 g=0~10 n = a number determined by the valence and periodicity of the elements in general formula I other than oxygen

[0252] 55. A method for preparing an α,β-unsaturated aldehyde and / or an α,β-unsaturated carboxylic acid, wherein an alkene and / or an alcohol is guided together with molecular oxygen through a fixed catalyst bed comprising a bed of the shaped unsupported catalyst body according to any one of embodiments 27 to 54.

[0253] 56. The method of embodiment 55, wherein propene is used as the alkene.

[0254] 57. A fixed bed reactor comprising a bed of the shaped unsupported catalyst body according to any of embodiments 27 to 55. [Example]

[0255] Example Preparation of shaped unsupported catalyst bodies K1 to K10: Example 1 The active multi-metal oxides are 12 Co7Fe3Bi 0.6 Si 1.6 K 0.08 O x 2. Preparation of a shaped unsupported catalyst precursor K1 having the formula:

[0256] The stirring vessels used were each filled in the presence of ambient air, and during the stirring / mixing process they were hermetically sealed with a lid having a pressure release valve to the atmosphere (1.01 bar).

[0257] a) Preparation of aqueous solution B A temperature-controllable stainless steel (EN 1.4541) cylindrical stirred vessel (volume 1.75 m) equipped with a stirrer 3 The reactor (1.3 m diameter) was initially charged with 430 kg of demineralized water and heated to 60° C. with stirring (70 rpm).

[0258] Then, with constant stirring, 0.61 kg of an aqueous potassium hydroxide solution (KOH 47.5% by weight) at a temperature of 20° C. was added within 1 minute while maintaining the temperature at 60° C. Then, while maintaining the temperature at 60° C., 136.2 kg of finely divided ammonium heptamolybdate tetrahydrate (Mo 54.3% by weight, supplier: Nippon Inorganic Chemical Industry Co., Ltd., 3-14-1 Funado, Itabashi-ku, Tokyo 174-0041, Japan) at a temperature of 25° C. was stirred in small portions and the resulting aqueous solution (which was slightly turbid as a result of a small amount of insoluble isopolymolybdate contaminant) was stirred (70 rpm) at 60° C. for a further 60 minutes.

[0259] b) Preparation of aqueous solution A A temperature-controllable cylindrical stainless steel (EN 1.4541) stirred vessel (volume 1.75 m) equipped with a stirrer 3A 1.3 m diameter vessel was initially charged with 212 kg of an aqueous solution of cobalt(II) nitrate in nitric acid (containing 12.5% ​​Co by weight, 27% nitrate by weight, prepared by dissolving cobalt metal (>99.6% Co by weight purity, from MFT Metals Ferro-Alloys Trading GmbH, D-41474 Viersen), less than 0.3% Ni by weight, less than 100 mg / kg Fe, and less than 50 mg / kg Cu ​​in aqueous nitric acid), and heated to 60° C. with stirring (70 rpm).

[0260] With continued stirring (70 rpm) and continued heating to 60°C, 78 kg of iron(III) nitrate nonahydrate melt (13.8% by weight Fe, less than 0.4% by weight alkali metals, less than 0.01% by weight chloride, less than 0.02% by weight sulfate from Dr. Paul Lohmann GmbH, D-81857 Emmerthal) was metered in at 60°C and the mixture was stirred (70 rpm) for a further 30 minutes at 60°C.

[0261] While maintaining the temperature at 60°C and continuing stirring (70 rpm), 72.6 kg of an aqueous bismuth nitrate solution (an aqueous solution containing 11.1% (by weight) Bi, 13% (by weight) nitrate, and prepared by dissolving bismuth metal (BE-1495 Tilly from Sidech SA, Bi purity greater than 99.997% (by weight)), less than 7 mg / kg Pb, less than 5 mg / kg Ni, Ag, and Fe, less than 3 mg / kg each of Cu and Sb, and less than 1 mg / kg each of Cd and Zn in an aqueous nitric acid solution) was added to the resulting aqueous solution at 60°C with continued stirring (70 rpm), and the solution was further stirred (70 rpm) at 60°C for 30 minutes.

[0262] c) Mixing of aqueous solution A and aqueous solution B Aqueous solution A at 60° C. was continuously metered within 15 minutes into vigorously stirred (70 rpm) aqueous solution B maintained at 60° C. The resulting aqueous suspension was stirred at 60° C. for a further 15 minutes.

[0263] d) Addition of silica sol to obtain aqueous mixture M Immediately after further stirring had ended, 12.6 kg of silica gel (47.5% by weight of SiO2) from Grace GmbH & KG, In der Hollerecke 1, D-67545 Worms, type LUDOX TM50, heated to 60°C, was added to the aqueous mixture obtained in c).

[0264] e) Spray drying of aqueous mixture M The aqueous mixture M was spray-dried immediately after its preparation. The aqueous mixture (suspension) M, which was continuously stirred at 60°C with a stirrer (40 rpm), was then spray-dried in a co-current hot air stream (gas inlet temperature: 350±10°C, gas outlet temperature: 140±5°C, gas flow rate: 2200±100 m 3 The mixture was spray-dried in a spray tower (model S-50-N / R from Niro A / S, made of 1.4541 stainless steel) with a centrifugal atomizer of the FS-15 type and an atomizer wheel of the AM8-150 type in a 1000 rpm (STP) / h (speed of the atomizer wheel: 20 000 rpm).

[0265] The resulting atomized powder was stored in an airtight container (200 L or 1000 L capacity, 25°C, atmospheric pressure) for 10 calendar days until further processing (shorter or longer intermediate storage times (up to 30 calendar days) did not affect the resulting results). The loss on ignition of the resulting atomized powder (calcined under excess still air at 600°C (powder temperature) for 3 hours) was 31±2% (by weight) of its starting weight. The atomized powder had a D50 of 35±10 μm at a dispersion pressure of 2.0 bar absolute (D50 means that 50% of the particles are smaller than the reported value).

[0266] f) Production of ring-shaped precursor Then, 100 kg of spray powder and 1 kg of graphite (type 3160 from Asbury Graphite Mills Inc., New Jersey 08802) were first charged into an inclined mixer (model: VIL, capacity: 200 l, Aachener Misch-und Knetmaschinenfabrik) with mixing and cutting blades (mixing blade speed: 39 rpm, cutting blade speed: 3000 rpm) and premixed for 5 minutes.

[0267] The resulting mixture was then compacted in a K200 / 100 compactor from Hosokawa Bepex GmbH using smooth rollers with concave grooves (roller diameter 100 mm, roller length 200 mm, gap width 2.8 mm, roller speed 5 rpm, target compaction force 80 kN, target compaction force per length 8 kN / cm). A monolithic vibrating screen from Allgaier (large screen size: 1.5 mm, small screen size: 200 μm) with a ball-shaped screening aid (diameter 22 mm) was used to isolate the compact with a particle size mostly between 200 μm and 1.5 mm.

[0268] For tableting, an additional 2.5% (by weight) of graphite (type 3160 from Asbury Graphite Mills Inc., NJ 08802) was added to the compaction in a turbulent mixer from Drais for 2 minutes.

[0269] The resulting granular material was then compacted (compressed) under a dry air atmosphere using a Korsch XT-600 rotary press (with a 65 EURO B die) to produce a non-curved (i.e., flat) mass (M v A ring-shaped molded precursor with a geometrical shape E×H×I=5 mm×5 mm×2 mm and an end surface of 188 mg was obtained. The initial compression force (compression force) applied was 0.7 kN. The main compression force (compression force) applied was 2.7 kN. The rotor speed was 40 rpm. The lateral crush strength (SDF) of the obtained ring-shaped molded precursor was V ) was 23 N.

[0270] g) Thermal pretreatment and calcination of the ring-shaped precursor prepared in f) The shaped rings were placed on the belt of a belt calcination apparatus (described in WO 2002 / 024620) having eight chambers (chamber width 100 cm, chamber length 150 cm).

[0271] Chambers 1 to 8 were each equipped with a ventilation system to generate air circulation, and the temperatures were adjusted to 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 air supply to each of chambers 1 to 8 was 90 m 3 (STP) / h, 130 m 3 (STP) / h, 255 m 3 (STP) / h, 90 m 3 (STP) / h, 150 m 3 (STP) / h, 90 m 3 (STP) / h, 90 m 3 (STP) / h, 140 m 3 (STP) / h. Waste air was removed from each chamber by a ventilation system. The air evacuation rate for each of chambers 1 to 8 was 130 m 3 (STP) / h, 290 m 3 (STP) / h, 305 m 3 (STP) / h, 144 m 3 (STP) / h, 135 m 3 (STP) / h, 80 m 3 (STP) / h, 80 m 3 (STP) / h, 130 m 3 (STP) / h.

[0272] The bed height of chambers 1 to 4 was 40 mm. The bed height of chambers 5 to 8 was 75 mm. Within the chambers, the temporal and local temperature fluctuations from the target value were always less than 10°C.

[0273] The belt speed was such that the residence time in the first four chambers was 105 minutes and in the fifth through eighth chambers was 270 minutes.

[0274] In this way, 2.6 t of shaped, unsupported catalyst bodies K1 were produced.

[0275] Example 2 (not according to the invention) Active multi-metal oxides are stoichiometric Mo 12 Co7Fe3Bi 0.6 Si 1.6 K 0.08 O x 2. Preparation of shaped unsupported catalyst bodies K2 having the following structure:

[0276] The shaped unsupported catalyst body K2 was produced in the same way as the shaped unsupported catalyst body K1, with the modification of f).

[0277] The molded precursor was weighed to a mass of 220 mg (M v The initial compression force (compression force) applied was 1.3 kN. The main compression force (compression force) applied was 6.8 kN. The lateral crushing strength (SDF) of the obtained ring-shaped molded precursor was V ) was 48 N.

[0278] Example 3 Active multi-metal oxides are stoichiometric Mo 12 Co7Fe3Bi 0.6 Si 1.6 K 0.08 O x 2. Preparation of shaped unsupported catalyst body K3 having:

[0279] The shaped unsupported catalyst body K3 was produced in the same way as the shaped unsupported catalyst body K1, with modifications f) and g).

[0280] The resulting granular material is compacted (compressed) in a dry air atmosphere using a Kilian E150+ rotary press (with a 21 EURO D die) at f) to produce a non-curved (i.e. flat) mass (M vA ring-shaped molded precursor with a geometrical shape E×H×I=5 mm×3 mm×2 mm and an end surface of 90 mg was obtained. The rotor speed was 25 rpm. The lateral crush strength (SDF) of the obtained ring-shaped molded precursor was V ) was 6 N.

[0281] 1000 g of the molded precursor prepared in step (f), equally divided among four mesh grids arranged side by side, each with a base area of ​​150 mm x 150 mm (bed height: 15 mm), was applied to an air circulation shaft oven (Nabertherm GmbH, D-28865 Lilienthal; oven model: S60 / 65A) with a pre-drying air flow of 4500 L (STP) / h (inlet temperature 140 °C) (the air circulation oven was kept at 25 °C). Subsequently, while maintaining the air flow (including its inlet temperature), the temperature in the air circulation shaft oven was changed as follows (the temperature values ​​refer to the temperature of the applied bulk material in each case. These were determined by four thermocouples located at the geometric center of the four mesh grids, each at the center of the applied bulk material. One of the thermocouples provided the actual value for temperature control of the air circulation shaft oven; the other thermocouples confirmed the same temperature within a range of ±0.1 °C). The temperature increase was essentially linear over time. The sample was heated from 25°C to 130°C within 72 minutes. The temperature was held at 130°C for 72 minutes, then increased to 190°C within 36 minutes. The temperature was held at 190°C for 72 minutes, then increased to 220°C within 36 minutes. The temperature was held at 220°C for 72 minutes, then increased to 265°C within 36 minutes. The temperature was held at 265°C for 72 minutes, then increased to 380°C within 93 minutes. The temperature was held at 380°C for 187 minutes, then increased to 430°C within 93 minutes. The temperature was held at 430°C for 187 minutes, then increased to the final firing temperature of 500°C within 93 minutes, which was held for 463 minutes. The sample was then cooled to 25°C within 12 hours. For this purpose, both the heating of the air circulation shaft oven and the airflow preheat were switched off (but the airflow itself of 4500 L(STP) / h was maintained, the inlet temperature of the airflow being 25° C.).

[0282] Example 4 (not according to the invention) Active multi-metal oxides are stoichiometric Mo 12 Co7Fe3Bi 0.6 Si 1.6 K 0.08 O x Preparation of shaped unsupported catalyst body K4 having

[0283] The shaped unsupported catalyst body K4 was produced in the same way as the shaped unsupported catalyst body K3, with the modification of f).

[0284] The molded precursor was weighed to a mass of 122 mg (M v The resulting ring-shaped precursor was compressed (tableted) to a lateral crushing strength (SDF) of 1000 mg / kg. V ) was 22 N.

[0285] Example 5 Active multi-metal oxides are stoichiometric Mo 12 Co 8.3 Fe 2.1 Bi 0.6 Si 1.6 K 0.08 O x Preparation of shaped unsupported catalyst body K5 having

[0286] The stirring vessels used were each filled in the presence of ambient air, and during the stirring / mixing process they were hermetically sealed with a lid having a pressure release valve to the atmosphere (1.01 bar).

[0287] a) Preparation of aqueous solution B A temperature-controllable stainless steel (EN 1.4541) cylindrical stirred vessel (volume 1.75 m) equipped with a stirrer 3 The reactor (1.3 m diameter) was initially charged with 654 kg of demineralized water and heated to 60° C. with stirring (70 rpm).

[0288] Then, with constant stirring, 0.36 kg of an aqueous potassium hydroxide solution (KOH 47.5% by weight) at a temperature of 20° C. was added within 1 minute while maintaining the temperature at 60° C. Then, while maintaining the temperature at 60° C., 80.4 kg of finely divided ammonium heptamolybdate tetrahydrate (Mo 54.3% by weight, supplier: Nippon Inorganic Chemical Industry Co., Ltd., 3-14-1 Funado, Itabashi-ku, Tokyo 174-0041, Japan) at a temperature of 25° C. was stirred in small portions and the resulting aqueous solution (which was slightly turbid as a result of a small amount of insoluble isopolymolybdate contaminant) was stirred (70 rpm) at 60° C. for a further 60 minutes.

[0289] b) Preparation of aqueous solution A A temperature-controllable cylindrical stainless steel (EN 1.4541) stirred vessel (volume 1.75 m) equipped with a stirrer 3 A 1.3 m diameter vessel was initially charged with 148.4 kg of an aqueous solution of cobalt(II) nitrate in nitric acid (containing 12.5% ​​Co by weight, 27% nitrate by weight, prepared by dissolving cobalt metal (>99.6% Co by weight purity, from MFT Metals Ferro-Alloys Trading GmbH, D-41474 Viersen), less than 0.3% Ni by weight, less than 100 mg / kg Fe, and less than 50 mg / kg Cu ​​in aqueous nitric acid), and heated to 60° C. with stirring (70 rpm).

[0290] With continued stirring (70 rpm) and continued heating to 60°C, at 60°C 32.3 kg of iron(III) nitrate nonahydrate melt (13.8% by weight Fe, less than 0.4% by weight alkali metals, less than 0.01% by weight chloride, less than 0.02% by weight sulfate from Dr. Paul Lohmann GmbH, D-81857 Emmerthal) was metered in and the mixture was stirred (70 rpm) at 60°C for a further 30 minutes.

[0291] While maintaining the temperature at 60°C and continuing stirring (70 rpm), 42.8 kg of a bismuth nitrate aqueous solution (11.1% (by weight) Bi, 13% (by weight) nitrate (NO3 - ), bismuth metal (BE-1495 Tilly Bi from Sidech SA with a purity of greater than 99.997% by weight), less than 7 mg / kg Pb, less than 5 mg / kg Ni, Ag, and Fe, less than 3 mg / kg each of Cu and Sb, and less than 1 mg / kg each of Cd and Zn in an aqueous nitric acid solution) was added and stirred (70 rpm) at 60°C for an additional 30 minutes.

[0292] c) Mixing of aqueous solution A and aqueous solution B Aqueous solution A at 60° C. was metered continuously within 15 minutes into vigorously stirred (70 rpm) aqueous solution B maintained at 60° C. The resulting aqueous suspension was stirred at 60° C. for a further 15 minutes.

[0293] d) Addition of silica sol to obtain aqueous mixture M Immediately after further stirring had ended, 7.4 kg of silica gel (47.5% by weight of SiO2) from Grace GmbH & KG, In der Hollerecke 1, D-67545 Worms, type LUDOX TM50, heated to 60°C, was added to the aqueous mixture obtained in c).

[0294] e) Spray drying of aqueous mixture M The aqueous mixture M was spray-dried immediately after its preparation. The aqueous mixture (suspension) M, which was continuously stirred at 60°C with a stirrer (40 rpm), was then spray-dried in a co-current hot air stream (gas inlet temperature: 350±10°C, gas outlet temperature: 140±5°C, gas flow rate: 2200±100 m 3 (STP) / h, speed of atomizer wheel: 20 000 rpm) in a spray tower (model S-50-N / R from Niro A / S, made of 1.4541 stainless steel).

[0295] The resulting atomized powder was stored in an airtight container (200 L or 1000 L capacity, 25°C, atmospheric pressure) for 10 calendar days until further processing (shorter or longer intermediate storage times (up to 30 calendar days) did not affect the resulting results). The loss on ignition of the resulting atomized powder (calcined under excess still air at 600°C (powder temperature) for 3 hours) was 31±2% (by weight) of its starting weight. The atomized powder had a D50 of 35±10 μm at a dispersion pressure of 2.0 bar absolute (D50 means that 50% of the particles are smaller than the reported value).

[0296] f) Production of ring-shaped precursor Then, 100 kg of spray powder and 1 kg of graphite (type 3160 from Asbury Graphite Mills Inc., New Jersey 08802) were first charged into an inclined mixer (model: VIL, capacity: 200 l, Aachener Misch-und Knetmaschinenfabrik) with mixing and cutting blades (mixing blade speed: 39 rpm, cutting blade speed: 3000 rpm) and premixed for 5 minutes.

[0297] The resulting mixture was then compacted in a K200 / 100 compactor from Hosokawa Bepex GmbH using smooth rollers with concave grooves (roller diameter 100 mm, roller length 200 mm, gap width 2.8 mm, roller speed 5 rpm, target compaction force 80 kN, target compaction force per length 8 kN / cm). A monolithic vibrating screen from Allgaier (large screen size: 1.5 mm, small screen size: 200 μm) with a ball-shaped screening aid (diameter 22 mm) was used to isolate the compact with a particle size mostly between 200 μm and 1.5 mm.

[0298] For tableting, an additional 2.5% (by weight) of graphite (type 3160 from Asbury Graphite Mills Inc., NJ 08802) was added to the compaction in a turbulent mixer from Drais for 2 minutes.

[0299] The granular material obtained as described is then compacted (compressed) under a dry air atmosphere using a Kilian E150+ rotary press (with 21 EURO D dies) to produce a non-curved (i.e. flat) mass (M v A ring-shaped molded precursor with a geometrical shape E×H×I=5 mm×3 mm×2 mm and an end surface of 102 mg was obtained. The rotor speed was 25 rpm. The lateral crush strength (SDF) of the obtained ring-shaped molded precursor was V ) was 12 N.

[0300] g) Thermal pretreatment and calcination of the ring-shaped precursor prepared in f) 1000 g of the prepared molded precursor, equally divided among four mesh grids arranged side by side, each with a base area of ​​150 mm x 150 mm (bed height: 15 mm), was placed in an air-circulating shaft oven (Nabertherm GmbH, D-28865 Lilienthal; oven model: S60 / 65A) with a pre-dried air flow of 4500 L (STP) / h (inlet temperature 140 °C) (the air-circulating oven was kept at 25 °C). Subsequently, while maintaining the air flow (including its inlet temperature), the temperature in the air-circulating shaft oven was changed as follows: (The temperature values ​​refer to the temperature of the applied bulk material in each case. These were determined by four thermocouples located at the geometric center of the four mesh grids, each at the center of the applied bulk material. One of the thermocouples provided the actual value for temperature control of the air-circulating shaft oven; the other thermocouples confirmed the same temperature within a range of ±0.1 °C.) The temperature increase was essentially linear over time. The temperature was heated from 25°C to 130°C within 72 minutes. The temperature was held at 130°C for 72 minutes, then increased to 190°C within 36 minutes. The temperature was held at 190°C for 72 minutes, then increased to 220°C within 36 minutes. The temperature was held at 220°C for 72 minutes, then increased to 265°C within 36 minutes. The temperature was held at 265°C for 72 minutes, then increased to 380°C within 93 minutes. The temperature was held at 380°C for 187 minutes, then increased to 430°C within 93 minutes. The temperature was held at 430°C for 187 minutes, then increased to the final firing temperature of 500°C within 93 minutes, which was held for 463 minutes. It was then cooled to 25°C within 12 hours. For this purpose, both the heating of the air circulation shaft oven and the airflow preheat were switched off (but the airflow itself of 4500 L(STP) / h was maintained, the inlet temperature of the airflow being 25° C.).

[0301] Example 6 (not according to the invention) Active multi-metal oxides are stoichiometric Mo 12 Co 8.3 Fe 2.1 Bi 0.6 Si 1.6 K0.08 O x Preparation of shaped unsupported catalyst body K6 having

[0302] The shaped unsupported catalyst body K6 was produced in the same way as the shaped unsupported catalyst body K5, with the modification of f).

[0303] The molded precursor was weighed to a mass of 119 mg (M v The resulting ring-shaped precursor was compressed (tableted) to a lateral crushing strength (SDF) of 1000 mg / kg. V ) was 26 N.

[0304] Example 7 Active multi-metal oxides are stoichiometric Mo 12 Co 8.3 Fe 2.1 Bi 0.6 Si 1.6 K 0.08 O x Preparation of shaped unsupported catalyst body K7 having

[0305] The shaped unsupported catalyst body K7 was produced in the same way as the shaped unsupported catalyst body K5, with the modification of f).

[0306] The resulting granular material was compacted (compressed) in a dry air atmosphere using a Korsch PH 865 rotary press (with a 65 die) to a mass (M v A ring-shaped precursor having a geometric shape E×H×I=5 mm×5 mm×2 mm and a weight of 166 mg with non-curved (i.e., flat) end faces was obtained. The rotor speed was 40 rpm. The lateral crush strength (SDF) of the obtained ring-shaped precursor was V ) was 10 N.

[0307] Example 8 Active multi-metal oxides are stoichiometric Mo 12 Co 8.3 Fe 2.1 Bi 0.6 Si 1.6 K 0.08 O x Preparation of shaped unsupported catalyst body K8 having

[0308] The shaped unsupported catalyst body K8 was produced in the same way as the shaped unsupported catalyst body K7, with the modification of f).

[0309] The molded precursor was weighed to a mass of 185 mg (M v The resulting ring-shaped precursor was compressed (tableted) to a lateral crushing strength (SDF) of 1000 mg / kg. V ) was 16 N.

[0310] Example 9 (not according to the invention) Active multi-metal oxides are stoichiometric Mo 12 Co 8.3 Fe 2.1 Bi 0.6 Si 1.6 K 0.08 O x Preparation of shaped unsupported catalyst body K9 having

[0311] The shaped unsupported catalyst body K9 was produced in the same way as the shaped unsupported catalyst body K7, with the modification of f).

[0312] The molded precursor was weighed to a mass of 205 mg (M v The resulting ring-shaped precursor was compressed (tableted) to a lateral crushing strength (SDF) of 1000 mg / kg. V ) was 26 N.

[0313] Example 10 (not according to the invention) Active multimetal oxide is stoichiometric [Bi2W2O92WO3] 0.40 ×[Mo 12 Co 5,4 Fe 3,1 Si 1,5 K 0,08 O x ]1, production of shaped unsupported catalyst body K10.

[0314] Shaped unsupported catalyst body K10 was prepared according to Example I of WO 2010 / 000720.

[0315] A ring-shaped molded precursor with a geometric shape E × H × I = 5 mm × 5 mm × 2 mm and non-curved (i.e., flat) end faces had a mass (M V ) Testing of ring-shaped unsupported catalysts K1-K10 prepared for the heterogeneously catalyzed partial oxidation of propene to acrolein and acrylic acid:

[0316] For the shaped unsupported catalyst bodies K1 to K6, a reaction tube (type 1.4541 stainless steel (EU standard number EN 10088-3); outer diameter 33.7 mm; wall thickness 2 mm; inner diameter 29.7 mm; length 400 cm, 4 mm thermowell) was used.

[0317] For the shaped unsupported catalyst bodies K7 to K10, a reaction tube (type 1.4541 stainless steel (EU standard number EN 10088-3); outer diameter 30 mm; wall thickness 2 mm; inner diameter 26 mm; length 400 cm, without thermowell) was used.

[0318] Each reactor tube was filled from bottom to top as follows: Section 1: Length 60 cm a preliminary bed of steatite rings with a geometric shape of 7 mm × 3 mm × 4 mm (external diameter × length × internal diameter; C220 steatite from CeramTec); Reaction zone: Consists of two sections (see Table 3, Zone 1 is closest to the reactor inlet) Section 2: Length 30 cm downstream bed of the same steatite ring as in section 1; Section 3: Empty Tubes

[0319] The structure of the reaction zone is shown in Table 3. The relative volume-specific catalytic activity was adjusted by diluting the shaped unsupported catalyst bodies with inert steatite rings of geometry 5 mm × 3 mm × 2 mm (outer diameter × length × inner diameter, C220 steatite from CeramTec) or geometry 5 mm × 5 mm × 2 mm (outer diameter × length × inner diameter, C220 steatite from CeramTec).

[0320] The reaction gas mixture flowing from top to bottom through each reaction tube packed as described above had the following content: 5.8% to 6.4% by volume of propene; 1.5% to 3% by volume of H2O, 0.2% to 0.5% by volume of CO, 0.6% to 1.0% by volume of CO2, 0.02% to 0.05% by volume of acrolein, 10.2% to 11.7% by volume of O2, and The remaining amount of molecular nitrogen to make 100%.

[0321] Over the length of the reactor tube, a stirred, externally electrically heated salt bath (a mixture of 53% (by weight) potassium nitrate, 40% (by weight) sodium nitrite and 7% (by weight) sodium nitrate; 50 kg of salt melt) flowed around the reactor tube in each case (flow rate in the tube was 3 m 3 / h (in a plane perpendicular to the longitudinal axis of the tube).

[0322] The temperature in the catalyst bed of the unsupported catalysts K1 to K6 was continuously measured by a thermocouple placed in a thermowell inside the reactor tube and pushed upward from the bottom into the reactor bed using a traction device. The maximum temperature in this measurement was the hot spot temperature T H It corresponded to.

[0323] The drop test is performed in this document as follows: 50 g of the shaped, unsupported catalyst bodies are dropped through a transparent, vertical tube 3.5 m long and 23 mm in diameter. The shaped, unsupported catalyst bodies fall into a porcelain dish directly below the tube and are separated from the dust and material destroyed during the impact. The intact shaped, unsupported catalyst bodies separated from the dust and decomposed material are weighed. The percentage of the shaped, unsupported catalyst bodies that are destroyed is determined by comparing the mass determined here with the mass of the shaped, unsupported catalyst bodies used. The percentage of the shaped, unsupported catalyst bodies that are destroyed is a measure of the mechanical stability of the shaped, unsupported catalyst bodies.

[0324] The value product selectivity (S (mol%)) in this specification means the following:

number

[0325] Comparisons of the respective pairs of Examples E1 / E2, E3 / E4, and E5 / E6, and comparisons of Examples E7 and E8 with Examples E9 and E10, show higher value product selectivity and significantly higher value product yield (with lower catalyst mass) for the shaped unsupported catalyst bodies of the present invention. At the same time, the shaped unsupported catalyst bodies of the present invention have sufficient mechanical stability.

[0326] [Table 1]

[0327] [Table 2]

[0328] [Table 3]

[0329] [Table 4]

Claims

1. 1. A method for producing a shaped unsupported catalyst body for the gas-phase oxidation of alkenes and / or alcohols to α,β-unsaturated aldehydes and / or α,β-unsaturated carboxylic acids, comprising: the shaped unsupported catalyst body comprises at least the elements molybdenum, bismuth, iron, and cobalt; a) producing an aqueous solution or suspension using in each case a source of at least one of the elemental components molybdenum, bismuth, iron, cobalt and optionally at least one source of the elemental component nickel, b) preparing a powder P by drying and optionally grinding the aqueous solution or suspension obtained in a), c) the powder P obtained in b), optionally with the addition of one or more auxiliaries, is homogeneously mixed and optionally compacted, and then compacted into a shaped precursor having a cylindrical structure, d) subjecting the shaped precursor obtained in c) to a heat treatment to form the shaped unsupported catalyst body; c) The pressure in the consolidation is set to a value in which the density of the shaped precursor is 1.70 to 2.30 g / cm ３ wherein the density of the shaped precursor is the mass divided by the geometric volume, and d) the weight loss during the heat treatment is selected to be between 25% and 40% by weight.

2. The cylindrical structure is i) a cylinder with a central circular opening along its length, or ii) a cylinder having three uniformly cut-out portions in the longitudinal direction and having three uniformly spaced circular openings in the longitudinal direction; The method of claim 1, wherein

3. MoO ３ 3. The method of claim 1, wherein the shaped unsupported catalyst body has a molybdenum content, calculated as: molybdenum content = 45 wt. % to 75 wt. %.

4. Bi ２ O ３ 4. The method of claim 1, wherein the bismuth content of the shaped unsupported catalyst bodies is from 1% to 20% by weight, calculated as:

5. Fe ２ O ３ 5. The method according to claim 1, wherein the shaped unsupported catalyst bodies have an iron content of from 2% to 12% by weight, calculated as:

6. 6. The method of any one of claims 1 to 5, wherein the total cobalt and nickel content of the shaped unsupported catalyst bodies, calculated as CoO and NiO, is from 9% to 30% by weight.

7. A shaped unsupported catalyst body having a cylindrical structure for the gas-phase oxidation of alkenes and / or alcohols to α,β-unsaturated aldehydes and / or α,β-unsaturated carboxylic acids, which can be obtained by the method according to any one of claims 1 to 6, the shaped unsupported catalyst body comprises at least the elements molybdenum, bismuth, iron, and cobalt; The density of the shaped unsupported catalyst body is 1.20 to 1.70 g / cm ３ where the density of the shaped unsupported catalyst body is the mass divided by the geometric volume; The total pore volume of the shaped unsupported catalyst body is 0.33 to 0.60 cm ３ / g, The shaped unsupported catalyst body has a volume of pores in the range of 0.1 to 1 μm that is 85% to 99% of the total pore volume, wherein the total pore volume and the volume of pores in the range of 0.1 to 1 μm are determined by mercury porosimetry.

8. The cylindrical structure is i) a cylinder with a central circular opening along its length, or ii) A cylinder with three uniform longitudinal cutouts and three uniformly spaced circular openings along its length.

8. The shaped unsupported catalyst body of claim 7, wherein:

9. 9. The shaped unsupported catalyst body according to claim 8, wherein the shortest distance between the outer wall of the cylindrical body and the adjacent opening is 0.75 to 2.5 mm.

10. The density of the shaped unsupported catalyst body is 1.35 to 1.55 g / cm ３ 10. The shaped unsupported catalyst body according to claim 7, wherein

11. The shaped unsupported catalyst body has a total pore volume of 0.36 to 0.45 g / cm ３ 11. The shaped unsupported catalyst body according to claim 7, wherein

12. 12. The shaped unsupported catalyst body of claim 7, wherein the volume of pores in the range of 0.1 to 1 μm of the shaped unsupported catalyst body is 88% to 96% of the total pore volume.

13. 13. A process for preparing an α,β-unsaturated aldehyde and / or an α,β-unsaturated carboxylic acid, wherein an alkene and / or an alcohol is guided together with molecular oxygen over a fixed catalyst bed comprising a bed of the shaped unsupported catalyst body of any one of claims 7 to 12.

14. 14. The process according to claim 13, wherein the propene is used as the alkene.

15. A fixed bed reactor comprising a bed of the shaped unsupported catalyst body of any one of claims 7 to 12.

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