DE102011079035A1 - Molybdenum, bismuth and iron containing multi-metal oxide composition useful for catalyzing a heterogeneously catalyzed partial gas phase oxidation of alkane, alkanol, alkanal, alkene and/or alkenal on a catalyst bed - Google Patents

Abstract

Mo, Bi and Fe containing multimetal oxide materials of general stoichiometry I, Mo ₁₂ Bi _a Co _b Fe _c K _d Si _e O _x (I), With

a = 0.5 to 1,
b = 7 to 8.5,
c = 1.5 to 3.0,
d = 0 to 0.15,
e = 0 to 2.5 and
x = the electrical neutrality of the multimetal oxide ensuring stoichiometric coefficient of O ^2- ,

such as

12 - b - 1.5 · c = A and 0.5 ≤ A ≤ 1.5,
0.2 ≤ a / A ≤ 1.3, and
2.5 ≤ b / c ≤ 9,

and their use.

Description

The present invention relates to Mo, Bi and Fe-containing multimetal oxide materials of general stoichiometry I, Mo ₁₂ Bi _a Co _b Fe _c K _d Si _e O _x (I), in which the variables have the following meaning:
a = 0.5 to 1,
b = 7 to 8.5,
c = 1.5 to 3.0,
d = 0 to 0.15,
e = 0 to 2.5 and
x = a number determined by the valency and frequency of the elements other than oxygen in I,
and meet the following conditions:
Condition 1: 12 - b - 1.5 · c = A,
and
0.5 ≤ A ≤ 1.5;
Condition 2: 0.2 ≤ a / A ≤ 1.3; and
Condition 3: 2.5 ≤ b / c ≤ 9.

Moreover, the present invention relates to processes for the preparation of multimetal oxide of general stoichiometry I, and their use as catalytic active compositions of catalysts for the heterogeneously catalyzed partial gas phase oxidation of organic compounds, in particular those of propene to acrolein as the main product and acrylic acid as a byproduct.

Mo, Bi and Fe-containing multimetal oxide of the general stoichiometry I, which do not meet the conditions 1, 2 and 3, are for example from DE-A 19855913 known.

From the DE-A 19855913 It is also known to use such multimetal oxide compositions as active compositions of catalysts for the heterogeneously catalyzed partial gas phase oxidation of propene to acrolein as the main product and acrylic acid as desired by-product (acrylic acid is therefore a desirable by-product because the heterogeneously catalyzed partial gas phase oxidation of propene to acrolein is the first Oxidation stage of the two-stage partial oxidation of propene to acrylic acid application applies).

A disadvantage of the multimetal oxide compositions DE-A 19855913 However, as the active compositions of catalysts for the heterogeneously catalyzed partial gas phase oxidation of propene to acrolein as the main product and acrylic acid as a desired by-product, it is particularly not possible to fully satisfy the resulting overall selectivity of the formation of acrolein and acrylic acid.

With respect to the multimetal oxide compositions of DE-A 19855913 The above also applies to the Mo, Bi and Fe containing multimetal oxide compositions of DE-A 10063162 , of the DE-A 102005037678 , of the DE-A 10059713 , of the DE-A 10049873 , of the DE-A 102007003076 , of the DE-A 102008054586 , of the DE-A 102007005606 and the DE-A 102007004961 to.

The object of the present invention was therefore, in particular, to provide Mo, Bi and Fe-containing multimetal oxide compositions which have improved overall selectivity of the formation of acrolein as active compositions of catalysts for the heterogeneously catalyzed partial gas phase oxidation of propene to acrolein as the main product and acrylic acid as by-product and acrylic acid (ie, improved total product value selectivity).

As a solution to the problem Mo, Bi and Fe containing multimetal oxide of general stoichiometry I, Mo ₁₂ Bi _a Co _b Fe _c K _d Si _e O _x (I), in which the variables have the following meaning:
a = 0.5 to 1,
b = 7 to 8.5,
c = 1.5 to 3.0,
d = 0 to 0.15,
e = 0 to 2.5 and
x = a number determined by the valency and frequency of the elements other than oxygen in I,
and meet the following conditions:
Condition 1: 12 - b - 1.5 · c = A,
and
0.5 ≤ A ≤ 1.5;
Condition 2: 0.2 ≤ a / A ≤ 1.3; and
Condition 3: 2.5 ≤ b / c ≤ 9,
made available.

According to the invention, the stoichiometric coefficient d is 0.04 to 0.1, and particularly preferably 0.05 to 0.08.

According to the invention, the stoichiometric coefficient e is advantageously 0.5 to 2, and particularly advantageously 0.8 to 1.8 or 1 to 1.6.

Moreover, for the condition 1, 0.5 ≦ A ≦ 1.25, and more preferably 0.5 ≦ A ≦ 1, is advantageously used.

For condition 2, according to the invention preferably 0.3 ≦ a / A ≦ 1.2, and more preferably 0.4 ≦ a / A ≦ 1.2, and most preferably 0.5 ≦ a / A ≦ 1.2.

The quotient b: c = b / c (condition 3) advantageously satisfies the relation 3 ≦ b / c ≦ 9, particularly advantageously the relation 3 ≦ b / c ≦ 7, and most preferably the relation 3 ≦ b / c ≤ 5.

Very particularly preferred multimetal oxide materials of general stoichiometry I are thus those in which the following applies at the same time:
d = 0.04 to 0.1;
e = 0.5 to 2;
0.5 ≤ A ≤ 1.25;
0.4 ≤ a / A ≤ 1.2; and
3 ≤ b / c ≤ 9.

Alternatively, very particular preference is given to multimetal oxide materials of the general stoichiometry I in which the following applies at the same time:
d = 0.04 to 0.1;
e = 0.8 to 1.8;
0.5 ≤ A ≤ 1;
0.5 ≤ a / A ≤ 1.2; and
3 ≤ b / c ≤ 5.

Multimetal oxide compositions of the general stoichiometry I according to the invention are usually mixed in bulk (as so-called full catalysts) into geometric shaped bodies, e.g. Formed spheres, rings or (full) cylinders, or in the form of shell catalysts, d. H. with the multimetal oxide (active) composition-coated preformed inert carrier (s) used to catalyze the respective heterogeneously catalyzed gas phase partial oxidation (e.g., from propene to acrolein). Of course, they can also be used in powder form as catalysts for such catalysis.

In principle, multimetal oxide (active) masses of the general stoichiometry I can be prepared in a simple manner by producing an intimate, preferably finely divided, dry mixture of appropriate stoichiometry from suitable sources of their (in particular non-oxygen) constituents. optionally calcined at temperatures in the range of 350 to 650 ° C after previously made to form moldings of regular or irregular geometry, which optionally takes place with the concomitant use of shaping aids. The calcination can take place either under inert gas or under an oxidative atmosphere such as air (or another mixture of inert gas and molecular oxygen) as well as under reducing atmosphere (eg a mixture of inert gas, NH ₃ , CO and / or H ₂ ) or under vacuum. The calcination time may be several minutes to several hours and usually decreases with the calcination temperature.

Suitable sources of the elemental constituents of the multimetal oxide materials of general stoichiometry I (the multimetal oxide active materials I) are those compounds which are already oxides and / or compounds which can be converted into oxides by heating, at least in the presence of oxygen are.

In addition to the oxides, suitable starting compounds (sources) are, in particular, halides, nitrates, formates, oxalates, citrates, acetates, carbonates, amine complexes, ammonium salts and / or hydroxides and also hydrates of the abovementioned salts. Compounds such as NH ₄ OH, (NH ₄ ) CO ₃ , NH ₄ NO ₃ , NH ₄ CHO ₂ , CH ₃ COOH, NH ₄ CH ₃ CO ₂ and / or ammonium oxalate, which disintegrate to gaseous compounds escaping at the latest during calcination and / / or can be decomposed, can be incorporated in the intimate dry mixture in addition. As such in the calcining decomposing substances are also organic materials such as stearic acid, malonic acid, ammonium salts of the aforementioned acids, starches (eg potato starch and corn starch), cellulose, ground nut shells and finely divided plastic flour (eg polyethylene, polypropylene, etc.) into consideration ,

The intimate mixing of the starting compounds (sources) for the preparation of multimetal oxide active compounds I can be carried out in dry or in wet form. If it takes place in dry form, the starting compounds (the sources) are expediently used as finely divided powders and after mixing and, if appropriate, compacting, subjected to the geometric precursor shaped body of the calcination. Preferably, however, the intimate mixing takes place in wet form.

Advantageously in accordance with the invention, the starting compounds are mixed together in the form of solutions and / or suspensions, and the resulting wet mixture M is subsequently dried to give the intimate dry mixture. The solvent and / or suspending agent used is preferably water or an aqueous solution.

Very particularly intimate dry mixtures are obtained in the above-described mixing method when starting exclusively from sources present in dissolved form and / or from colloidally dissolved sources of the elemental constituents. In general, a parent compound may be a source for only one or more than one elemental constituent. Accordingly, an abovementioned solution or colloidal solution may have only one or even more than one elemental constituent dissolved. Preferred solvent is, as already said, water. The drying of the resulting aqueous mixtures is preferably carried out by spray drying.

If in the present document a solution of a source (starting compound, starting substance) in a solvent (for example water) is mentioned, then the term "dissolving" in the sense of a molecular or ionic solution is meant. That is, the largest geometric unit in the solution of the dissolved starting substance (source) inevitably has "molecular" dimensions.

In contrast, colloidal solutions provide a connection between true (molecular and / or ionic) solutions and suspensions. In these colloidal disperse systems are smaller accumulations of molecules or atoms, which, however, are not detectable by the naked eye or the microscope. The colloidal solution appears optically completely clear (although often colored), since the particles contained in it only have a diameter of 1 to 250 nm (preferably up to 150 nm and more preferably up to 100 nm). Due to the small size, a separation of the colloidally dissolved particles by conventional filtration is not possible. However, they can be separated from their "solvent" by ultrafiltration with membranes of vegetable, animal or synthetic origin (e.g., parchment, pig's blister or cellophane). In contrast to the "optically empty" true (molecular and / or ionic) solutions, a light beam can not pass through a colloidal solution without being distracted. The light beam is scattered and deflected by the colloidally dissolved particles. In order to keep colloidal solutions stable and to prevent further particle agglomeration, they often contain wetting and dispersing aids and other additives added.

For example, the element silicon (the elemental constituent Si) in the form of a silica sol for the preparation of the wet (eg aqueous) mixture M can be introduced. Silica sols are colloidal solutions of amorphous silica in water. They are water-soluble and contain no sedimentable constituents. Their SiO ₂ content can be up to 50% by weight and more, often lasting for years (without sedimentation).

Of course, in a solution of at least one element source to be used for producing a wet (eg aqueous) mixture M, sources dissolved in molecular and / or ionic form as well as colloidally dissolved sources can be present side by side in solution.

In the context of the production of multimetal oxide active compounds I according to the invention, a favorable Mo source is ammonium heptamolybdate tetrahydrate. Further possible Mo sources are ammonium orthomolybdate ((NH ₄ ) ₂ MoO ₄ ), ammonium dimolybdate ((NH ₄ ) ₂ Mo ₂ O ₇ ), ammonium tetramolybdate dihydrate ((NH ₄ ) ₂ Mo ₄ O ₁₃ .5H ₂ O) and ammonium decamolybdate dihydrate (( NH ₄ ) ₄ Mo ₁₀ O ₃₂ × 2H ₂ O). In principle, however, it is also possible, for example, to use molybdenum trioxide.

Preferred K source for preparing multimetal oxide compositions I according to the invention is KOH (potassium hydroxide). In principle, however, KNO ₃ or its hydrate can also be used as K source.

As a Bi source salts of bismuth are preferably used for the preparation of inventive Multimetalloxidaktivmassen I, which have the Bi as Bi ³⁺ . Examples of such salts are bismuth (III) oxide, bismuth (III) oxide nitrate (bismuth subnitrate), bismuth (III) halide (eg fluoride, chloride, bromide, iodide) and in particular bismuth (III) nitrate pentahydrate.

Fe sources which are preferred according to the invention are salts of Fe ³⁺ , of which the various iron (III) nitrate hydrates are particularly preferred (cf., for example, US Pat DE-A 102007003076 ). According to the invention, particular preference is given to using iron (III) nitrate nonahydrate as the Fe source. It is of course also possible to use salts of Fe ²⁺ as Fe source in the context of a preparation according to the invention of multimetal oxide active compounds I.

According to the invention, at least 50 mol%, more preferably at least 75 mol% and preferably at least 95 mol% in the form of an Fe source are introduced for the preparation of multimetal oxide compositions I according to the invention, based on the molar total amount of Fe contained in them as Fe has ³⁺ . Also Fe sources can be used which have both Fe ²⁺ and Fe ³⁺ .

Co-sources which are suitable according to the invention are its salts which have the Co as Co ²⁺ and / or Co ³⁺ . As such are exemplified the cobalt (II) nitrate hexahydrate, the Co ₃ O ₄ , the CoO, the cobalt (II) formate and the cobalt (III) nitrate called. The former of these sources is particularly preferred.

Frequently, the preparation of a wet (eg aqueous) mixture M according to the invention preferably takes place in air (advantageously, the aqueous mixture M is saturated in air). This is especially true when salts of Co ²⁺ and salts of Fe ²⁺ are used as cobalt and iron source. Especially if these salts are the nitrates and / or their hydrates. This advantage is not least based on the fact that Fe ²⁺ and Co ²⁺ can be at least partially oxidized to Fe ³⁺ or Co ³⁺ in the presence of NO ₃ by the molecular oxygen of the air.

As already mentioned, the wet mixture M according to the invention is preferably an aqueous mixture M, which is produced with particular advantage in the following manner. From at least one source of the elements Co, Fe and Bi, an aqueous solution A is prepared whose pH is ≦ 3, preferably ≦ 2, more preferably ≦ 1 and most preferably ≦ 0. In general, the pH of the aqueous solution A is not less than -2 and is particularly advantageously in the range -1 to 0. Preferably, the aqueous solution A is an aqueous solution of the nitrates or nitrate hydrates of Co, Bi and Fe , The aqueous solution A is particularly preferably an aqueous solution of the nitrates or nitrate hydrates in aqueous nitric acid. To prepare such a solution, the element source can also be directly solutions of the relevant elements in aqueous nitric acid.

An aqueous solution B is prepared from at least one source of the element Mo and optionally one or more sources of the element K. According to the invention, the pH of the aqueous solution B is advantageously (based on 25 ° C. and 1.01 bar) <7. The pH of the aqueous solution B is particularly preferably ≦ 6.5, and very particularly advantageously ≦ 6. In the US Pat As a rule, the pH of the aqueous solution B will be 3. Favorable solutions B to be used according to the invention have a pH of 4 to 6. In this document, pH values of aqueous solutions generally refer (unless explicitly stated otherwise) to a measurement at 25 ° C. and 1 atm (1.01 bar) with a glass electrode designed as a single-rod measuring chain. The calibration of the same takes place by means of buffer solutions whose pH value is known and which is close to the desired measured value. In particular, it is suitable for the determination of pH values in According to the invention, the Mettler Toledo pH electrode Inpro 4260/425 / Pt 100, which is a combination electrode with integrated temperature sensor Pt 100 for automatic temperature compensation.

If the aqueous solution contains BK, it is advantageous to use KOH as its source for the preparation of the aqueous solution B. Preferred Mo source for preparing an aqueous solution B is ammonium heptamolybdate tetrahydrate ((NH ₄ ) ₆ Mo ₇ O ₂₄ × 4H ₂ O).

The total content of the aqueous solution A of Co, Fe and Bi is according to the invention expedient, based on the amount of water contained in the aqueous solution A, 10 to 25 wt .-%, advantageously 15 to 20 wt .-%.

The total content of the aqueous solution B to Mo according to the invention is expedient, based on the amount of water contained in the aqueous solution B, 3 to 25 wt .-%, advantageously 5 to 15 wt .-%.

Subsequently, the aqueous solution A and the aqueous solution B are suitably mixed together in terms of application technology. Advantageously in accordance with the invention, the aqueous solution A is continuously stirred into the aqueous solution B. Advantageously in accordance with the invention, the initially introduced aqueous solution B is stirred vigorously. The total content of the resulting aqueous mixture of aqueous solution A and aqueous solution B of Mo, Co, Fe and Bi is expedient according to the invention, based on the amount of water contained in the aqueous mixture, 5 to 25 wt .-%, preferably 8 to 20 wt .-%.

The temperature of the initially introduced aqueous solution B and the intensely stirred aqueous mixture resulting from the stirring of the aqueous solution A in the present invention is advantageously (preferably throughout the mixing process) ≦ 80 ° C., better ≦ 70 ° C., even better ≦ 60 ° C. and preferably ≦ 40 ° C. As a rule, the aforementioned temperature will not fall below 0 ° C. Advantageously, the aqueous solution A stirred into solution B has the same temperature as the initially introduced solution B. The temperature of the aqueous original is preferably constant over the course of the stirring process described. For this purpose, for example, be thermostated by means of a water bath. The working pressure is suitably in terms of application at 1.01 bar (1 atm).

Preferably, the aqueous solution A is stirred into the initially introduced aqueous solution B over a period of time ranging from 5 to 60 minutes, more preferably within a period of 10 to 30 minutes and most preferably within a period of 15 to 25 minutes. The resulting aqueous mixture is subsequently, preferably while maintaining the stirring temperature, suitably used for 5 to 60 minutes, preferably 10 to 30 minutes and more preferably stirred for 15 to 25 minutes.

Essentially, the size of the period during which the aqueous solution A and the aqueous solution B are combined has no influence on the selectivity of the multimetal oxide active mass I produced in the further course. Excessive stirring (≥ 4 h) reduces the selectivity. It has also been shown that the size of the abovementioned periods exert a certain influence on the activity of the multimetal oxide active mass I produced in the further course. Thus, a slower stirring of the aqueous solution A into the aqueous solution B promotes the activity, while too rapid stirring of the aqueous solution A into the aqueous solution B reduces the activity. The latter also applies to excessive stirring (for example ≥ 3 h, or ≥ 4 h).

The ratio V, formed from the total molar amount n ₁ of NH ₃ and NH ₄ ⁺ optionally contained in the aqueous mixture of the aqueous solution A and the aqueous solution B, and the total molar amount of n ₂ in Mo contained in the same aqueous mixture (V = n ₁ : n ₂ ) is advantageously adjusted according to the invention such that V ≦ 1.5, preferably ≦ 1, and more preferably ≦ 6/7. In principle, V can also be 0. The pH of the aqueous mixture of aqueous solution A and aqueous solution B is advantageously at the same time ≦ 3, better ≦ 2. As a rule, it is at values ≥ 0.

If the desired multimetal oxide active material I contains the elemental constituent Si, aqueous silica sol (cf., for example, US Pat DE-A 102006044520 ) and this is stirred into the aqueous mixture of aqueous solution A and aqueous solution B in an expedient manner, wherein this aqueous mixture prior to this stirring advantageously water can be added. Conveniently, both the aqueous silica sol and the water may be added at once. Both the temperature of the water and the temperature of the aqueous silica sol In this case, the temperature of the aqueous mixture of aqueous solution A and aqueous solution B corresponds advantageously. Finally, stirring is continued for up to 30 minutes in an expedient manner. During the stirring, the aforementioned temperature is advantageously maintained. The SiO ₂ content of the added aqueous silica sol may be 15 to 60% by weight, or 20 to 60% by weight, or 30 to 60% by weight, preferably 40 to 60% by weight, and more preferably 45 to 55 Wt .-% amount (in each case based on its total weight).

Instead of initially introducing the aqueous solution B in a thermostatically stirred container and then stirring the aqueous solution A while stirring in it, both the aqueous solution B and the aqueous solution A can be continuously fed to the stirred container (for example by a " 3-way T-mixer "through). In principle, the aqueous solution B can also be continuously stirred into an initially introduced aqueous solution A. However, this procedure is less preferred according to the invention.

In an alternative embodiment, an aqueous solution A * is generated from sources of the elements Fe and Bi. From sources of elements Co and Mo, and optionally K, an aqueous solution B * is generated. Subsequently, the aqueous solution A * and the aqueous solution B * are mixed together (preferably, the aqueous solution A * is stirred into the aqueous solution B *). The resulting aqueous mixture of aqueous solution A * and aqueous solution B * can then be added again as needed as Si source aqueous silica sol. With regard to the pH of the various aqueous solutions, possible sources of elemental constituents and with respect to the ratio V in the resulting aqueous mixture of aqueous solution A * and aqueous solution B *, what has already been said in connection with the aqueous solutions A, B and their mixture applies corresponding way.

During the preparation of aqueous solutions A, B and the mixture thereof, as already mentioned. Preferably, in the presence of gaseous molecular oxygen (e.g., in the presence of air), in the case of preparation of the aqueous solutions A *, B *, as well as their mixture, it has proved advantageous to operate in the absence of molecular oxygen.

As a rule, the aqueous mixture M obtainable as described is an aqueous suspension (the aqueous mixtures M preferably also contain the ratios V described as being advantageous (molar total amount of NH ₃ + NH ₄ ⁺ to be contained) In addition, the pH of the aqueous mixture M obtainable as described is advantageously ≦ 3, as a rule 0 to 2). According to the invention, aqueous mixtures M obtainable as described advantageously contain no more or less than 60% of the total amount of Co contained in them in the aqueous medium (at the temperature and the working pressure at which the aqueous mixture M was produced). Preferably, the proportion of AT mentioned above dissolved in the aqueous medium of the aqueous mixture M is the total amount of Co present in the aqueous mixture M at values ≦ 50% and particularly preferably at values ≦ 40%, or ≦ 30% or ≦ 20 %. The total content of the aqueous mixture M of Mo, Co, Fe, Bi and Si to be dried (preferably spray-dried) is expedient according to the invention, based on the amount of water contained in the aqueous mixture M, from 5 to 25% by weight 8 to 20% by weight. As a rule AT is ≥ 10%, or ≥ 15%. The transfer of the aqueous mixture M into a finely divided intimate dry mixture takes place according to the invention preferably by spray-drying the aqueous mixture M. That is to say, the aqueous mixture M is first broken up into finely divided droplets and the same is subsequently dried. According to the invention, the spray-drying preferably takes place in the hot air stream. In principle, however, other hot gases can also be used for the abovementioned spray drying (for example nitrogen or air diluted with nitrogen and other inert gases).

The spray drying can be done both in cocurrent and in countercurrent of the droplets to the hot gas. Typical gas inlet temperatures are in the range of 250 to 450 ° C, preferably 270 to 370 ° C. Typical gas outlet temperatures are in the range of 100 to 160 ° C. Preferably, the spray drying is carried out in countercurrent of the droplets to the hot gas.

Of course, the aqueous mixture M can also be dried by conventional evaporation (preferably at reduced pressure, the drying temperature will generally not exceed 150 ° C). In principle, the drying of an aqueous mixture M can also be carried out by freeze-drying.

In principle, the dried aqueous mixture M can be calcined as such to form a multimetal oxide (active) composition of general stoichiometry I according to the invention. Especially if the Drying of the aqueous mixture M was carried out by spray drying, however, the resulting spray powder is often too finely divided for an immediate Kalcination. In this case, the spray powder can be coarsened, for example, by subsequent compacting. If the compaction takes place dry, it is possible to mix in advance the compaction, for example finely divided graphite and / or other shaping aids (for example lubricants and / or reinforcing agents) mentioned in this document, under the spray powder (for example with a Röhnrad mixer). For example, the compaction can be performed with a calender having two counter-rotating steel rolls. Subsequently, the compactate can be purposefully shredded to the particle size appropriate for the contemplated reuse. This can be done in the simplest way, for example, by pressing the compact material through a sieve of defined mesh size.

The compacting can basically be done wet. For example, the spray powder can be kneaded with the addition of water. Following the kneading, the kneaded mass can be comminuted to the desired fine particle size in accordance with the subsequent use (cf. DE-A 10049873 ) and dried.

The finely divided precursor materials obtainable as described can now be calcined as such and the multimetal oxide (active) bulk I powder obtainable as such can be used as catalyst for catalyzing heterogeneously catalyzed partial gas phase oxidations of, for example, propene to acrolein. Alternatively, the obtained multimetal oxide (active) bulk I powder but also first formed into moldings of regular or irregular geometry and the resulting moldings are used as catalysts for the heterogeneously catalyzed partial gas phase oxidation of eg propene to acrolein (see, eg DE-A 10063162 ).

For example, from the powder form of the active composition, by compaction to the desired catalyst geometry (e.g., by tableting, extruding, or extruding), solid catalysts can be prepared, optionally with adjuvants such as e.g. Graphite or stearic acid as lubricants and / or shaping aids and reinforcing agents such as microfibers of glass, asbestos, silicon carbide or potassium titanate can be added. Suitable unsupported catalyst geometries are e.g. Solid cylinder or hollow cylinder with an outer diameter and a length of 2 to 10 mm. Of course, the full catalyst may also have spherical geometry, wherein the ball diameter may be 2 to 10 mm.

Of course, the shaping of the powdered active composition can also be carried out by applying to the outer surface of preformed inert catalyst supports. The coating of the carrier tablets for the preparation of such coated catalysts can be carried out, for example, in a suitable rotatable container, as it is known from DE-A 10063162 , of the DE-A 2909671 , of the EP-A 293859 , of the EP-A 714700 and the DE-A 4442346 is known.

Alternatively, for the preparation of coated catalyst moldings, the coating of the carrier tablets with the uncalcined precursor powder can be carried out by itself and the calcination can be carried out only after the application has taken place and optionally drying (cf., for example, US Pat DE-A 10049873 ).

The carrier tablets to be used for the preparation of coated catalysts are preferably chemically inert, d. that is, they take part in the course of the catalyzing partial gas phase oxidation of e.g. Propensity to acrolein is essentially not one. Suitable materials for the carrier moldings according to the invention are, in particular, aluminum oxide, silicon dioxide, silicates such as clay, kaolin, steatite, pumice, aluminum silicate and magnesium silicate, silicon carbide, zirconium dioxide and thorium dioxide (in particular steatite C220 from CeramTec).

The surface of the carrier molding can be both smooth and rough. Advantageously, the surface of the carrier molded body is rough, since an increased surface roughness usually requires an increased adhesive strength of the applied shell of finely divided oxidic active material or finely divided precursor composition. Frequently, the surface roughness R _{z of} the carrier molding is in the range from 40 to 200 μm, often in the range from 40 to 100 μm (determined according to US Pat DIN 4768 Part 1 with a "Hommel tester for DIN-ISO surface measurement sizes" from Hommelwerke, DE ). Furthermore, the support material may be porous or non-porous. Conveniently, the carrier material is nonporous (the total volume of the pores is based on the volume of the carrier molded body advantageously 1 ≤ Vol .-%).

The fineness of the applied to the surface of the carrier molding finely divided mass is of course adapted to the desired shell thickness. For the range of a shell thickness of 100 to 500 microns, for example, finely divided masses, of which at least 50% of the powder particles are a sieve of Mesh size 1 to 10 microns happen and their proportion of particles with a longest extent (= longest direct line connecting two points on the surface) above 50 microns less than 1% (based on the total number of particles) is. As a rule, the distribution of the longitudinal extents of the powder particles corresponds to the production of a Gaussian distribution.

For coating the carrier tablets, the surface of the carrier tablets and / or the finely divided powder mass to be applied is expediently moistened with a liquid binder (for example water or organic solvents such as glycerol or a mixture thereof) and the cup body is applied after application, e.g. dried again by means of hot air. The layer thickness of the finely divided powder mass applied to the carrier molding is expediently chosen to lie in the range from 10 to 1000 .mu.m, preferably in the range from 100 to 700 .mu.m and more preferably in the range from 300 to 500 .mu.m. Possible shell thicknesses are also 10 to 500 μm or 200 to 300 μm.

The support molding itself may, as already mentioned, be regularly or irregularly shaped, with regularly shaped support bodies such as spheres, solid cylinders or hollow cylinders being preferred. For example, the use of spherical shaped carrier bodies whose diameter is 1 to 8 mm, preferably 4 to 5 mm, is suitable according to the invention. However, it is also suitable to use cylinders as carrier shaped bodies whose length is 2 to 10 mm and whose outer diameter is 4 to 10 mm. In the case of inventively suitable rings as a carrier molding, the wall thickness is moreover usually 1 to 4 mm. Cylinder dimensions suitable according to the invention are also 3 to 6 mm (length), 4 to 8 mm (outer diameter) and, in the case of rings, 1 to 2 mm (wall thickness). Of course, suitable ring geometry according to the invention is also considered to be 2 to 4 mm (length), 4 to 8 mm (outer diameter) and 1 to 2 mm (wall thickness). Striking carrier ring geometries which are distinctive according to the invention are, for example, 7 mm × 3 mm × 1.5 mm (outer diameter × length × wall thickness) and 5 mm × 3 mm × 1.5 mm (outer diameter × length × wall thickness). In particular, drying and / or thermal treatment (calcination) after application of the shell as in the DE-A 10063162 as well as the DE-A 10049873 be described described.

However, according to the invention, it is particularly advantageous to form moldings of regular or irregular geometry from finely divided precursor material (from the finely divided intimate dry mixture of the sources of the elemental constituents) in an appropriately functional manner by compacting (compressing or compacting) and thereafter by thermal treatment (calcining) in so-called Vollkatalysatorformkörper be transferred.

This procedure is particularly preferred when the intimate mixing of the starting compounds (sources) of the relevant elemental constituents of the multimetal oxide composition I to the finely divided intimate dry mixture takes place in dry form (cf., for example, US Pat WO 2008/087116 and DE-A 102008042060 ).

Lubricants such as graphite, carbon black, polyethylene glycol, polyacrylic acid, stearic acid, starch, mineral oil, vegetable oil, water, boron trifluoride and / or boron nitride may, for example, be added as further finely divided shaping aids. Also suitable as shaping aids are reinforcing agents, such as microfibers made of glass, asbestos, silicon carbide or potassium titanate, which, after completion of shaping, have a positive effect on the cohesion of the resulting compact (the resulting molded article). A co-use of lubricants in the context of a corresponding shaping can be found for example in the writings DE-A 102007004961 . WO 2008/087116 . WO 2005/030393 . US-A 2005/0131253 . WO 2007/017431 . DE-A 102007005606 and in the DE-A 102008040093 described.

According to the invention, exclusively finely divided graphite is preferably used as the lubricant. In this case, suitable finely divided graphites to be used are, in particular, those which are described in the documents WO 2005/030393 . US-A 2005/0131253 . WO 2008/087116 and DE-A 102007005606 recommended. This applies in particular to those graphites which are used in these documents in the examples and comparative examples. Especially preferred graphites are Asbury 3160 and Asbury 4012 the company Asbury Graphite Mills, Inc., New Jersey 08802, USA and Timrex ^® T44 Timcal Ltd., 6743 Bodio, Switzerland.

Based on the weight of the finely divided precursor composition to be formed, this may e.g. up to 15% by weight of finely divided lubricant (e.g., graphite). However, the lubricant content in the finely divided precursor composition (in the finely divided intimate dry mixture) is usually ≦ 9% by weight, in many cases ≦ 5% by weight, often ≦ 4% by weight; this is especially true when the finely divided lubricant is graphite. In general, the aforementioned additional amount is ≥ 0.5 wt .-%, usually ≥ 2.5 wt .-%.

As a rule, the densification of the finely divided, optionally shaping aids comprehensive, precursor material (the finely divided intimate dry mixture) to the desired geometry of the shaped body (the geometric Katalysatorvorläuferformkörpers) by the action of external forces (pressure) on the precursor material. The forming apparatus to be used or the forming method to be used are subject to no restriction.

For example, the compacting shaping can take place by extrusion, tabletting or extrusion. The finely divided precursor composition (the finely divided intimate dry mixture) is preferably used dry to the touch. However, it can e.g. contain up to 10% of their total weight of substances which are liquid under normal conditions (25 ° C, 1 atm (1.01 bar)). Also, the finely divided precursor mass (the finely divided intimate dry mix) may contain solid solvates (e.g., hydrates) having such liquid substances in chemically and / or physically bound form. Of course, the finely divided precursor composition may also be completely free of such substances.

According to preferred molding method by compacting the finely divided precursor composition (the fine-particle intimate dry mixture) is the tableting. The basic features of tabletting are eg in "The Tablet", Handbook of Development, Production and Quality Assurance, WARitschel and A.Bauer-Brandl, 2nd edition, Edition Verlag Aulendorf, 2002 described and transferred in a completely corresponding manner to a required tabletting method.

Advantageously, a tabletting according to the invention as in the writings WO 2005/030393 . DE-A 102008040093 . DE-A 102008040094 and WO 2007/017431 described carried out. The temperature surrounding the tabletting machine is normally 25 ° C. In terms of application technology, the particle diameters of the precursor material to be compacted (the finely divided intimate dry mixture), optionally as the result of pre-coarsening by compaction, are in the range 100 to 2000 .mu.m, preferably 150 to 1500 .mu.m, more preferably 400 to 1250 .mu.m, or 400 to 1000 .mu.m, or 400 to 800 μm (molding aid previously mixed in with the compaction is not taken into account).

Like the forming apparatus to be used for compaction or the forming method to be used, the desired geometry of the resulting shaped bodies is not subject to any restriction in the method according to the invention. That is, the catalyst precursor moldings produced during compaction may be both regular and irregularly shaped, with regularly shaped moldings generally being preferred according to the invention.

For example, the catalyst precursor shaped body may have spherical geometry. The ball diameter may e.g. 2 to 10 mm, or 4 to 8 mm. However, the geometry of the catalyst precursor shaped body can also be fully cylindrical or hollow cylindrical (annular).

In both cases, outside diameter and height (length) may be e.g. 2 to 10 mm, or 2 to 8 mm, or 3 to 8 mm.

In the case of hollow cylinders (rings) is usually a wall thickness (wall thickness) of 1 to 3 mm appropriate. Of course, as catalyst precursor geometries but also all those geometries are considered that in the WO 02/062737 disclosed and recommended. In the case of solid cylinders, the outer diameter may also be 1 to 10 mm.

The forming pressures to be performed in the course of a densification of finely divided precursor material (finely divided intimate dry mixture) to be carried out as described will advantageously be 50 kg / cm ² to 5000 kg / cm ² according to the invention. Preferably, the forming pressures are from 200 to 3500 kg / cm ² , more preferably from 600 to 2500 kg / cm ² .

In particular, in the case of annular precursor moldings (which are referred to in the literature regardless of their form as green compacts), the compression according to the invention according to the invention should advantageously be carried out so that the lateral compressive strength SD of the resulting molded article (see. DE-A 102008040093 . DE-A 102008040094 and WO 2005/030393 ) satisfies 12 N ≦ SD ≦ 35 N, preferably 15 N ≦ SD ≦ 30 N, and more preferably satisfies 19 N ≦ SD ≦ 30 N.

The experimental determination of lateral compressive strength is as in the writings WO 2005/030393 such as WO 2007/017431 described carried out. Of course, ring-like green compacts, like the DE-A 102008040093 recommends very particularly preferred according to the invention. The end face of annular or ring-like shaped bodies can be both curved and not curved in the described production method of green bodies according to the invention (cf. DE-A 102007004961 . EP-A 184790 and the DE-A 102008040093 ). When determining the height of such geometric shaped body, such a curvature is not taken into account.

According to the invention, particularly advantageous ring geometries of moldings obtainable by compacting finely divided precursor material (finely divided intimate dry mixture) satisfy the condition height / outer diameter = H / A = 0.3 to 0.7. Particularly preferred is H / A = 0.4 to 0.6. Furthermore, it is favorable for annular or ring-like green compacts according to the invention if the ratio I / A (where I is the inner diameter of the ring geometry) is 0.3 to 0.7, preferably 0.4 to 0.7.

The aforementioned ring geometries are particularly advantageous if they simultaneously have one of the advantageous H / A ratios and one of the advantageous I / A ratios. Such possible combinations are e.g. H / A = 0.3 to 0.7 and I / A = 0.3 to 0.8 or 0.4 to 0.7. Alternatively, H / A can be 0.4 to 0.6 and I / A can be 0.3 to 0.8 or 0.4 to 0.7 at the same time. Furthermore, it is favorable for the relevant ring geometries if H is 2 to 6 mm and preferably 2 to 4 mm. Furthermore, it is advantageous if A in the rings 4 to 8 mm, preferably 4 to 6 mm. The wall thickness of inventively preferred green ring geometries is 1 to 1.5 mm.

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

In general, it proves advantageous for the process according to the invention if each of the finely divided intimate dry mixtures to be produced from the sources of the elemental constituents of the multimetal oxide composition I other than oxygen with sources used undergoes a degree of dispersion in the course of the preparation of the finely divided intimate dry mixture characterized in that its diameter d ^Q ₉₀ ≤ 5 microns.

The requirement d ^Q ₉₀ ≦ 5 μm is basically fulfilled when dissolving a source in a solvent (the term "dissolving" is meant in the sense of a molecular or ionic solution). This is due to the fact that when dissolving a source (starting compound) in a solvent, the source is molecularly or ionically divided in the solvent. That is, the largest geometric unit of solute starting material (source) in the solution inevitably has "molecular" extents, thus necessarily being much smaller than 5 μm (as already stated, an initial compound can be a source of more than one element and a solution may have more than one source solved).

However, the requirement d ^Q ₉₀ ≤ 5 μm is also satisfied when a source of an element is in a solvent in colloidal solution, since the units contained in it have a diameter of 1 to 250 nm, and therefore the associated d ^Q _{90 is} necessarily ≦ 5 microns.

However, the requirement d ^Q ₉₀ ≤ 5 μm is also fulfilled if, for example, a source is comminuted dry to this particle size (eg by grinding).

The particle diameter d ^Q ₉₀ refers to the particle diameter distribution of the dry powder, which is to be determined as follows.

The finely divided powder is passed through a dispersing trough into the dry disperser Scirocco 2000 (from Malvern Instruments Ltd., Worcestershire WR14 1AT, United Kingdom), where it is dry-dispersed with compressed air and blown into the measuring cell in the free jet. In this will then after ISO 13320 determined with the laser diffraction spectrometer Malvern Mastersizer S (also from Malvern Instruments Ltd.), the volume-related particle diameter distribution.

A particle diameter d _x related to such a particle diameter distribution is defined such that X% of the total particle volume consists of particles with this or a smaller diameter. That is, (100 - X)% of the total particle volume consists of particles with a diameter> d _x . Unless expressly stated otherwise in this document, particle diameter determinations and d _x taken from them, such as d ₉₀ , d ₅₀ and d _10, refer to one used in the determination (the strength of the dispersion of the dry powder during the measurement determining) dispersing pressure of 2 bar absolute. d ^Q ₉₀ is such a particle diameter d _{90 of} a powdery source.

All statements made in this document with respect to an X-ray diffractogram refer to an X-ray diffraction pattern produced using Cu-K _α radiation (Theta-Theta Bruker D8 Advance diffractometer, tube voltage: 40 kV, tube current: 40 mA, aperture diaphragm V20 (variable) , Diffuser aperture V20 (variable), detector aperture (0.1 mm), measurement interval (2Θ = 2 theta): 0.02 °, measurement time per step: 2.4 s, detector: Si semiconductor detector).

All information in this document about specific surfaces of solids refers to determinations DIN 66131 (Determination of the specific surface area of solids by gas adsorption (N ₂ ) according to Brunauer-Emmert-Teller (BET)), unless expressly stated otherwise.

All data in this document on total pore volumes and on pore diameter distributions to these total pore volumes refer to determinations by the method of mercury porosimetry using the device Auto Pore 9500 from Micromeritics GmbH, D-41238 Mönchengladbach (range 0.003-300 μm).

According to the invention, unsupported catalyst precursor moldings have as low a residual moisture as possible. This is especially true if the intimate mixing of the various sources of the elemental constituents other than oxygen of the multimetal oxide composition I took place wet (in particular if it was carried out to form an aqueous mixture M).

According to the invention, the residual moisture content of green compacts according to the invention is preferably ≦ 10% by weight, better ≦ 8% by weight, even better ≦ 6% by weight, and most preferably ≦ 4% by weight or ≦ 2% by weight. (Residual moisture determination can be carried out as described in "The Library of Technology", Volume 229, "Thermo-gravimetric Material Moisture Determination", Fundamentals and Practical Applications, Horst Nagel, Verlag für den Modernindustrie (eg with the aid of a Computrac MAX 5000 XL from Arizona Instruments)) ,

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

The microwave irradiates in this procedure with very low power (0.1 mW), the material to be examined (the latter undergoes substantially no change in its temperature due to the relatively low power). The material components are polarized differently strong. In response, the microwave loses speed and energy. The influence of water molecules is much greater than the influence of other components, which allows the selective determination of residual water contents. This is because, due to their size and their dipole property, water molecules are particularly well able to follow an alternating electromagnetic field in the microwave frequency range by means of dipole orientation. In doing so, they absorb energy and change the electromagnetic alternating field with their electrical properties. This field weakening and field change is based on the measuring principle. For example, a weak microwave field can be built up over the sensor surface of a planar sensor and the resonance frequency of the sensor system can be analyzed permanently by scanning the microwave frequency. Bringing a water-containing material to be measured over the sensor, the resonance frequency shifts and its amplitude is attenuated. Both, damping and resonance frequency shift increase with increasing amount of water, so also with increasing bulk density of the material to be measured. However, the ratio of frequency shift and damping is a density-independent measure of the percentage of water and thus the key to moisture measurement. The ratio forms the so-called microwave moisture measurement, which represents the total moisture. Since the microwave resonance method is an indirect humidity measurement method, calibration is necessary. In such a calibration measurement with the sensor material samples are measured with a defined humidity. The combination of the microwave moisture readings with the associated defined absolute moisture content then forms the calibration of the measuring system. The measuring accuracy is usually ± 0.1% humidity (for example, the water humidity can be determined with a Sartorius PMD300PA online moisture meter).

Against this background, a spray-drying of a wet (for example aqueous) mixture M should already be carried out so that the resulting spray powder has the lowest possible residual moisture content.

Green compacts produced according to the invention should, taking into account the aspect just considered, be stored as far as possible in the absence of (ambient humidity) ambient air (preferably storage until calcination under anhydrous inert gas or under previously dried air).

Advantageously according to the invention, the formation of finely divided, intimate dry mixture is already carried out with the exclusion of ambient air (having air humidity) (for example under an N ₂ atmosphere).

The calcination of the green compacts (or in general of finely divided precursor powder or coated with this carrier moldings) is usually carried out at temperatures that reach or exceed at least 350 ° C in the rule. Normally, however, the temperature of 650 ° C. is not exceeded in the course of calcination (the term "calcination temperature" in this document means the temperature present in the calcination product). According to the invention, the temperature is preferably 600 ° C., preferably the temperature of 550 ° C. and frequently the temperature of 500 ° C., within the scope of the calcination. Further, in the above Kalcination preferably the temperature of 380 ° C, advantageously the temperature of 400 ° C, with particular advantage the temperature of 420 ° C and most preferably the temperature of 440 ° C exceeded. The Kalcination can also be divided in its timing in several sections.

According to experience, a thermal treatment at temperatures of .gtoreq.120.degree. C. and .ltoreq.350.degree. C., preferably .gtoreq.150.degree. C. and .ltoreq.320.degree. C., particularly preferably .gtoreq.220.degree. C. and .ltoreq.290.degree. C., is advantageously carried out in advance of the calcination.

Such a thermal treatment is suitably carried out for application purposes until the constituents contained within the mass to be thermally treated and decomposing under the conditions of the thermal treatment to gaseous compounds have been largely (preferably completely) decomposed into gaseous compounds (the time required in this regard may be, for example, 3 hours to 10 hours, often 4 hours to 8 hours). This is generally the case if, on the one hand, the molar amount of cations other than metal ions contained in the mass subsequently to be calcined, based on the total molar amount of cations present, is ≦ 20 mol% (preferably ≦ 10 mol%). ) and on the other hand, the molar amount of anions other than O ² , based on the total molar amount of anions contained, also in the same mass is also ≦ 20 mol% (preferably ≦ 10 mol%).

Temperature windows according to the invention for the final calcination temperature are therefore in the temperature range 400 ° C. to 600 ° C., or preferably in the temperature range 420 to 550 ° C., or more preferably in the temperature range 400 to 500 ° C.

The total duration of the calcination usually extends to more than 10 h. In most cases, treatment periods of 45 h or 25 h are not exceeded as part of the calcination. Often the total calcination time is less than 20 hours. In principle, a shorter calcination time is generally sufficient at higher calcination temperatures than at lower calcination temperatures.

In an embodiment of the invention which is advantageous according to the invention, 500 ° C. are not exceeded and the duration of calcination in the temperature window ≥ 430 ° C. and ≦ 500 ° C. extends to> 10 to ≦ 20 h.

The entire thermal treatment (including a decomposition phase) of a precursor material (eg a green compact) can be carried out both under inert gas and under an oxidative atmosphere such as air (or other mixture of inert gas and molecular oxygen) and under reducing atmosphere (eg a mixture of inert gas , NH ₃ , CO and / or H ₂ or under methane, acrolein, methacrolein). Of course, the thermal treatment can also be carried out under vacuum. Also, the atmosphere can be made variable over the course of the thermal treatment.

According to the invention, the thermal treatment (in particular the calcination phase) preferably takes place in an oxidizing atmosphere. In terms of application technology, this consists predominantly of stagnant or (preferably) agitated air (particularly preferably, the mass to be thermally treated (the calcination material) flows through an air stream). However, the oxidizing atmosphere may also consist of a stationary or agitated mixture of, for example, 25% by volume of N ₂ and 75% by volume of air, or 50% by volume of N ₂ and 50% by volume. % Air, or 75 vol .-% N ₂ and 25 vol .-% air exist (a treatment atmosphere of 100 vol .-% N ₂ is also possible).

In principle, the thermal treatment (for example the calcination) of the precursor material (eg the green compacts) can be carried out in the most varied types of furnaces, for example heatable recirculating air chambers (circulating air ovens, eg recirculating air shaft ovens), tray furnaces, rotary kilns, belt calciners or shaft kilns. According to the invention, the thermal treatment (for example the calcination) is advantageously carried out in a belt calcining apparatus such as the one described in US Pat DE-A 10046957 and the WO 02/24620 recommend. A hot spot formation within the material to be treated (within the Kalcinationsgutes) is largely avoided by the fact that with the help of fans by a Kalcinationsgut carrying gas-permeable conveyor belt increased flow rates of Kalcinationsatmosphäre be promoted by the Kalcinationsgut.

In the context of the thermal treatment of the precursor materials (for example the green compacts) to be carried out as described, it is possible to retain with grafting agents used both in the resulting shaped catalyst body and at least partially gaseous by thermal and / or chemical decomposition to gaseous compounds (eg CO, CO ₂ ) escape this. In the context of a catalytic use of the same, the shaping assistants remaining in the shaped catalyst body act in the same to dilute essentially exclusively the multi-element oxide I active mass. Basically, the thermal treatment in this regard as in the US 2005/0131253 described described.

Typically, the lateral compressive strengths of annular unsupported catalyst bodies obtainable according to the invention as described are 5 to 15 N, frequently 6 to 13 N or 8 to 11 N.

The specific (BET) surface area of multimetal oxide (active) compositions I according to the invention (in particular if they have been formed into annular unsupported catalysts as described above) is advantageously from 2 to 20 or to 15 m ² / g, preferably from 3 to 10 m, in terms of application technology ² / g, and more preferably 4 to 8 m ² / g. According to the invention, the associated total pore volume is advantageously in the range from 0.1 to 1 cm ³ / g or to 0.8 cm ³ / g, preferably in the range from 0.1 to 0.5 cm ³ / g and particularly preferably in the range 0 , 2 to 0.4 cm ³ / g.

If one plots the pore diameter in μm on the abscissa and the logarithm of the differential contribution in cm ³ / g of the respective pore diameter to the total pore volume in cm ³ / g on the ordinate, particularly favorable multimetal oxide (active) compositions I (especially if They are, as described above, formed into annular unsupported catalysts) usually a monomodal distribution (has only one maximum). If the contribution of pores with a pore radius ≤ 0.1 μm to the total pore volume ≤ 0.05 cm ³ / g results in particularly good overall target product selectivities (eg in the case of a heterogeneously catalyzed partial oxidation of propene to acrolein and / or acrylic acid). In the event that the contribution of such comparatively narrow pores to the total pore volume is> 0.05 cm ³ / g, an increase of the calcination time and / or the calcination temperature can be used to bring about a reduction of this contribution that is advantageous according to the invention.

In addition, it proves to be advantageous for increased total target product selectivity, if the contribution of pores with a pore radius in the range of 0.2 to 0.4 microns to the total pore volume, based on the total pore volume, ≥ 70 vol .-%, advantageously ≥ 75 vol .-%, particularly advantageously ≥ 85 vol .-%, preferably ≥ 90 vol .-%, particularly preferably ≥ 95 vol .-%.

Of course, the multimetal oxide (active) composition of general stoichiometry I according to the invention can also be used diluted with inert materials for the catalysis of heterogeneously catalyzed partial gas phase oxidations. As such inert diluent materials are suitable among other burned at high temperatures and thus comparatively poor in pore element oxides such as alumina, silica, thoria and zirconia. But also finely divided silicon carbide or finely divided silicates such as magnesium and aluminum silicate or steatite can be used for the aforementioned purpose. In terms of application technology, it will be advantageous, for example, for the calcined multimetal oxide (active) composition of the general stoichiometry I to be ground to a finely divided powder. This is then suitably mixed in terms of application technology with finely divided diluent material and the resultant mixed powder is molded into a geometric shaped body (preferably by tableting) using a shaping method presented in this document. By subsequent recalcining, the same is then transformed into the associated shaped catalyst body. Of course, the finely divided inert diluent material can also be incorporated, for example, already in a wet (eg aqueous) mixture M beforehand drying thereof. Furthermore, incorporation of finely divided inert diluent material in a finely divided dry mixture of sources of elemental constituents of the multimetal oxide mass I into it. However, such approaches are less preferred in the present invention.

In particular, multimetal oxides (active) materials of general stoichiometry I (or the same, comprising unsupported catalyst bodies) produced according to the described advantageous preparation processes are characterized by having substantially no local centers of elemental oxides (for example iron oxide or cobalt oxide). Rather, these elements are largely part of complex, mixed, Fe, Co and Mo containing Oxomolybdate. This has proved to be favorable with regard to an inventively desired minimization of unwanted full combustion of organic reaction gas mixture constituents according to the invention in the context of the relevant heterogeneously catalyzed partial oxidations.

Inventive multimetal oxide (active) compositions of the general stoichiometry I are suitable as active materials for the catalysis of heterogeneously catalyzed partial gas phase oxidations of alkanes, alkanols, alkenes and / or alkenals having from 3 to 6 carbon atoms (with partial oxidations in this document, in particular such reactions should be more organic) Compounds under reactive action of molecular oxygen to be understood, in which the partially oxidized organic compound contains at least one oxygen atom chemically bound after completion of the reaction than before performing the partial oxidation). The term partial oxidation should also be understood in this document to mean oxidative dehydrogenation and partial ammoxidation, ie. h., a partial oxidation in the presence of ammonia.

Particularly suitable according to the invention are multimetal oxide (active) compositions of the general stoichiometry I for catalyzing the heterogeneously catalyzed partial gas phase oxidation of propene to acrolein, isobutene to methacrolein and for catalysing the heterogeneously catalyzed partial gas phase ammpropriation of propene to acrylonitrile and of isobutene to methacrylonitrile ,

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) Acrylic acid (methacrylic acid), as exemplified in the WO 2006/42459 is described.

As a result, a by-product formation of acrylic acid (methacrylic acid) accompanied by a heterogeneously catalyzed partial gas phase oxidation of propene (isobutene) to acrolein (methacrolein) is generally not undesirable and usually subsumes below the desired value product formation.

The abovementioned applies in particular to inventive, multimetal oxide compositions of the general stoichiometry I comprehensive, Vollkatalysatorformkörper.

The heterogeneously catalyzed partial oxidation (in particular that of propene to acrolein) can, for example, as in the publications DE-A 102007004961 . WO 02/49757 . WO 02/24620 . DE-A 102008040093 . WO 2005/030393 . EP-A 575897 . WO 2007/082827 . WO 2005/113127 . WO 2005/047224 . WO 2005/042459 . WO 2007/017431 . DE-A 102008042060 . WO 2008/087116 . DE-A 102010048405 . DE-A 102009047291 . DE-A 102008042064 . DE-A 102008042061 and DE-A 102008040094 be described described.

The ring geometries of the annular unsupported catalysts obtainable as described in this document are particularly advantageous if the loading of the catalyst charge with propene contained in the reaction gas input mixture, isobutene and / or tert. Butanol (or its methyl ether) ≥ 130 Nl / l catalyst charge · h (precursors and / or replacements of pure inert material are not considered as belonging to the catalyst charge in load considerations in this document, the volume of the catalyst charge is otherwise the bulk volume in the reactor located).

However, the advantageous properties of annular unsupported catalyst bodies (or other multimetal oxide (active) compositions of general stoichiometry I (shaped catalyst bodies) are also present if the aforementioned load on the catalyst charge is ≥ 140 Nl / l.h or ≥ 150 Nl In the normal case, the aforesaid load on the catalyst feed becomes ≦ 600 Nl / L · h, often ≦ 500 Nl / L · h, many times ≦ 400 Nl / L · h or ≦ 350 Nl / l · h are loads in the range of ≥ 160 Nl / l · h to ≤ 300 or ≤ 250 or ≤ 200 Nl / l · h are particularly useful.

Under the load of a catalyst fixed bed with reaction gas input mixture is in this document, the amount of reaction gas input mixture in Normlitern (= Nl, the volume in liters, which is the corresponding Reaction gas input mixture amount under normal conditions, ie, at 0 ° C and 1 atm (1.01 bar) would take) understood that the fixed catalyst bed, based on the volume of its bed (bed sections of pure inert material are not included), ie, on its bulk volume per hour, is fed (-> unit = Nl / l · h).

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

Of course, catalysts obtainable according to the invention (for example annular unsupported catalyst bodies) can be used as catalysts for the partial oxidation of propene to acrolein or of isobutene and / or tert. Butanol (or its methyl ether) to methacrolein even with loads of the catalyst charge with the partially oxidized starting compound of ≤ 130 Nl / l · h, or ≤ 120 Nl / l · h, or ≤ 110 Nl / l · h, in accordance with the invention more advantageous Be operated way. In general, however, this load will be at values of ≥ 60 Nl / l ·h, or ≥ 70 Nl / l ·h, or ≥ 80 Nl / l ·h.

• a) die Belastung der Katalysatorbeschickung mit Reaktionsgaseingangsgemisch (das Reaktionsgasgemisch, das dem Katalysatorfestbett zugeführt wird), und/oder
• b) den Gehalt des Reaktionsgaseingangsgemischs mit der partiell zu oxidierenden Ausgangsverbindung.

In principle, the loading of the catalyst charge with the starting compound to be partially oxidized (propene, isobutene and / or tert-butanol (or its methyl ether)) can be adjusted by means of two adjusting screws:

• a) the load of the catalyst feed with reaction gas input mixture (the reaction gas mixture which is fed to the fixed catalyst bed), and / or
• b) the content of the reaction gas input mixture with the starting compound to be partially oxidized.

The catalysts obtainable according to the invention (eg annular unsupported catalyst bodies) are also suitable, in particular, when the catalyst charge with the organic compound to be oxidized is above 130 Nl / lh in most cases via the aforesaid adjusting screw a) ,

The propene content (isobutene content or tert-butanol portion (or the methyl ether content)) in the reaction gas input mixture is generally (ie, essentially independent of the load) 4 to 20% by volume, frequently 5 to 15% by volume, or 5 to 12% by volume, or 5 to 8% by volume (in each case based on the total volume (s) of the reaction gas input mixture).

Frequently, the gas phase partial oxidation process of the catalysts obtainable as described (eg annular unsupported catalyst bodies or other geometric shaped catalyst bodies) partial oxidation (substantially independent of the load) in a partially oxidized (organic) compound (eg propene): oxygen: indifferent gases (including water vapor) volume ratio in the reaction gas input mixture of 1: (1.0 to 3.0) :( 5 to 25), preferably 1: (1.5 to 2.3) :( 10 to 20).

Under indifferent gases (or inert gases) are understood to mean those gases which remain unchanged in the course of the partial oxidation to at least 95 mol%, preferably at least 98 mol% chemically.

In the reaction gas input mixtures described above, the inert gas may be ≥20 vol%, or ≥30 vol%, or ≥40 vol%, or ≥50 vol%, or ≥60 vol. %, or at least ≥70 vol.%, or ≥80 vol.%, or ≥90 vol.%, or ≥95 vol.% of molecular nitrogen.

However, when the catalyst charge with the organic compound to be partially oxidized is ≥ 150 Nl / l · h, the concomitant use of inert diluent gases such as propane, ethane, methane, pentane, butane, CO ₂ , CO, water vapor and / or noble gases for the reaction gas input mixture recommended (but not mandatory). In general, however, these inert gases and their mixtures can also be used even at lower loads on the catalyst feed with the organic compound to be partially oxidized. Also, cycle gas can be used as diluent gas. Under circulating gas is understood to mean the residual gas which remains when the target compound is essentially selectively separated from the product gas mixture of the partial oxidation. It should be noted that the partial oxidation to acrolein or methacrolein with the present invention available z. B. annular shaped catalyst bodies only the first stage of a two-stage partial oxidation to acrylic acid or methacrylic acid may be as the actual target compounds, so that the recycle gas is then usually only after the second stage. In the context of such a two-stage partial oxidation, the product mixture of the first stage as such, if appropriate after cooling and / or secondary oxygen addition (as a rule as air), is generally fed to the second partial oxidation stage.

In the partial oxidation of propene to acrolein, using the catalysts obtainable as described (eg annular shaped catalyst bodies), a typical composition of the reaction gas input mixture measured at the reactor inlet (irrespective of the selected load) may contain, for example, the following components: 6 to 6.5% by volume propene, 1 to 3.5 vol.% H ₂ O, 0.2 to 0.5 vol.% CO, 0.6 to 1.2% by volume CO ₂ , 0.015 to 0.04 vol.% acrolein, 10.4 to 11.3% by volume O ₂ , and as residual amount ad 100% by volume of molecular nitrogen; or: 5.6 vol.% propene, 10.2% by volume Oxygen, 1.2% by volume CO _x , 81.3% by volume N ₂ , and 1.4% by volume H ₂ O.

The first compositions are suitable in particular for propene loadings of ≥ 130 Nl / l.h and the latter composition in particular for propene loadings <130 Nl / l.h, in particular ≦ 100 Nl / l.h of the fixed catalyst bed.

Suitable alternative compositions of the reaction gas input mixture for a propene partial oxidation to acrolein (regardless of the chosen load) are those which have the following component contents: 4 to 25 vol.% propene, 6 to 70 vol.% Propane, 5 to 60 vol.% H ₂ O, 8 to 65 vol.% O ₂ , and 0.3 to 20 vol.% H ₂ ; or 4 to 25 vol.% propene, 6 to 70 vol.% Propane, 0 to 60 vol.% H ₂ O, 8 to 16 vol.% O ₂ , 0 to 20 vol.% H ₂ , 0 to 0.5 vol.% CO, 0 to 1.2% by volume CO ₂ , 0 to 0.04 vol.% acrolein, and as a residual amount ad 100% by volume of substantially N ₂ ; or 50 to 80 vol.% Propane, 0.1 to 20 vol.% propene, 0 to 10 vol.% H ₂ , 0 to 20 vol.% N ₂ , 5 to 15 vol.% H ₂ O, and so much molecular oxygen that the molar ratio of acid content of substance to propene content 1.5 to 2.5 be wearing. or 6 to 9 vol.% propene, 8 to 18% by volume molecular oxygen, 6 to 30 vol.% Propane, and 32 to 72 vol.% molecular nitrogen.

The reaction gas input mixture of a heterogeneously catalyzed partial propene oxidation with catalysts according to the invention to give acrolein can however also be composed as follows: 4 to 15 vol.% propene, 1.5 to 30 vol.% (often 6 to 15% by volume) of water, ≥ 0 to 10% by volume (preferably ≥ 0 to 5% by volume) of propene, Water, oxygen and nitrogen are different dene ingredients, so much molecular sow that the molar ratio of ent contained molecular oxygen tenem molecular propene 1.5 to 2.5 be carries, and as a residual amount up to 100 vol .-% Total molecular nitrogen.

Another possible reaction gas input mixture composition may include: 6.0% by volume propene, 60% by volume Air and 34 vol.% H ₂ O.

Alternatively, reaction gas input mixtures of the composition according to Example 1 of EP-A 990 636 , or according to Example 2 of EP-A 990 636 , or according to Example 3 of EP-A 1 106 598 , or according to Example 26 of EP-A 1 106 598 , or according to Example 53 of EP-A 1 106 598 be used for a propene partial oxidation to acrolein according to the invention.

Also suitable are the catalysts of the invention obtainable as described, for. B. annular shaped catalyst body, for the method of DE-A 10246119 respectively. DE-A 10245585.

Further reaction gas input mixtures which are suitable according to the invention can be in the following composition grid: 7 to 11 vol.% propene, 6 to 12 vol.% Water, ≥ 0 to 5 vol.% of propene, water, oxygen and stick substance of various components, so much molecular oxygen that contained the molar ratio of Propene to be contained in molecular oxygen is from 1.6 to 2.2, and as a residual amount up to 100 vol .-% total amount of molecular nitrogen.

In the case of methacrolein as the target compound, the reaction gas input mixture can in particular also as in DE-A 44 07 020 be composed described.

The reaction temperature for a heterogeneously catalyzed propene partial oxidation to acrolein according to the invention is, when using the catalysts of the invention obtainable as described (eg annular shaped catalyst bodies), frequently at 300 to 450 ° C., or up to 400 ° C., or up to 380 ° C. The same applies in the case of methacrolein as the target compound.

The reaction pressure for the abovementioned partial oxidations is generally from 0.5 to 1.5 or 3 to 4 or 4 bar (meaning in this document, unless expressly stated otherwise, always absolute pressures).

The total loading of the catalyst charge with the reaction gas input mixture in the abovementioned partial oxidations is typically 1000 to 10000 Nl / lh, usually 1500 to 5000 Nl / lh and often 2000 to 4000 Nl / lh.

As to be used in the reaction gas input mixture propene are mainly polymer grade propene and chemical grade propene into consideration, as z. B. the DE-A 102 32 748 describes.

The source of oxygen is usually air.

The partial oxidation in application of the catalysts according to the invention obtainable as described (for example the annular shaped catalyst bodies) can in the simplest case be achieved, for example. B. be carried out in a one-zone Vielkontaktrohr fixed bed reactor, as him DE-A 44 31 957 , the EP-A 700 714 and the EP-A 700 893 describe.

Usually, in the aforementioned tube bundle reactors, the contact tubes are made of ferritic steel and typically have a wall thickness of 1 to 3 mm. Their inner diameter is usually 20 to 30 mm, often 21 to 26 mm. A typical contact tube length amounts to z. B. at 3.20 m. In terms of application, the number of catalyst tubes accommodated in the tube bundle container amounts to at least 1000, preferably to at least 5000. Often the number of catalyst tubes accommodated in the reaction container is 15000 to 35000. Tube bundle reactors having a number of contact tubes above 40000 tend to be the exception. Within the container, the contact tubes are normally distributed homogeneously, the distribution is suitably chosen so that the distance between the central inner axes of closest contact tubes (the so-called contact tube pitch) is 35 to 45 mm (see. EP-B 468 290 ).

The partial oxidation can, however, also be carried out in a multizone (eg "two-zone") multi-contact-tube fixed bed reactor, such as the DE-A 199 10 506 , the DE-A 103 13 213 , the DE-A 103 13 208 and the EP-A 1,106,598 especially at elevated loads of the catalyst charge with the partially oxidized organic compound recommend. A typical contact tube length in the case of a two-zone multi-contact fixed bed reactor is 3.50 m. Everything else is essentially as described in the single-zone multi-contact fixed bed reactor. Around the catalyst tubes, within which the catalyst feed is located, a heat exchange medium is guided in each tempering zone. As such are z. B. Melting of salts such as potassium nitrate, potassium nitrite, sodium nitrite and / or sodium nitrate, or of lower melting metals such as sodium, mercury and alloys of various metals. The flow rate of the heat exchange medium within the respective tempering zone is usually chosen so that the Temperature of the heat exchange medium from the point of entry into the temperature zone to the exit point from the temperature zone by 0 to 15 ° C, often 1 to 10 ° C, or 2 to 8 ° C, or 3 to 6 ° C increases.

The inlet temperature of the heat exchange medium, which, viewed over the respective temperature control, can be conducted in cocurrent or in countercurrent to the reaction gas mixture is preferably as in the publications EP-A 1,106,598 . DE-A 199 48 523 . DE-A 199 48 248 . DE-A 103 13 209 . EP-A 700 714 . DE-A 103 13 208 . DE-A 103 13 213 . WO 00/53557 . WO 00/53558 . WO 01/36364 . WO 00/53557 as well as the other writings cited in this document as prior art recommended. Within the tempering zone, the heat exchange medium is preferably guided in meandering fashion. In general, the multi-contact fixed-bed reactor also has thermal tubes for determining the gas temperature in the catalyst bed. Conveniently, the inner diameter of the thermo tubes and the diameter of the inner receiving sleeve for the thermocouple is chosen so that the ratio of heat of reaction evolving volume to heat dissipating surface is the same or only slightly different in thermal tubes and work tubes. The pressure loss should be the same for work tubes and thermo tubes, based on the same GHSV. A pressure loss compensation in the thermal tube can be done for example by adding split catalyst to the shaped catalyst bodies. This compensation is expediently homogeneous over the entire thermal tube length. Incidentally, the filling of thermal tubes as in the EP-A 873783 be designed described.

For the preparation of the catalyst charge in the catalyst tubes, as already mentioned, only catalysts according to the invention which can be obtained as described (eg the annular shaped catalyst bodies) or z. B. also largely homogeneous mixtures of as available obtainable z. B. annular shaped catalyst bodies and no active material having, with respect to the heterogeneously catalyzed partial gas phase oxidation substantially inert behaving moldings are used. As materials for such inert molded body z. Example, porous or non-porous aluminas, silica, zirconia, silicon carbide, silicates such as magnesium or aluminum silicate and / or steatite (for example, the type C220 from CeramTec, DE) into consideration.

The geometry of such inert shaped diluent bodies can in principle be arbitrary. D. h., It may, for example, balls, polygons, solid cylinders or else, such as. B. in the case of annular shaped catalyst body, rings. Often one will choose as inert diluent moldings whose geometry corresponds to that of the catalyst molding to be diluted with them. However, the geometry of the shaped catalyst body can also be changed along the catalyst charge or shaped catalyst bodies of different geometry can be used in substantially homogeneous mixing. In a less preferred procedure, the active composition of the catalyst molding can also be changed along the catalyst charge.

More generally, as already mentioned, the catalyst feed is advantageously designed so that the volume-specific (i.e., normalized to the unit of volume) activity in the flow direction of the reaction gas mixture either remains constant or increases (continuous, discontinuous or stepwise).

A reduction of the volume-specific activity can be easily z. B. be achieved by a uniform amount of inventively produced z. B. annular shaped catalyst bodies with inert diluent bodies homogeneously diluted. The higher the proportion of the diluent molding is selected, the lower is the active material or catalyst activity contained in a certain volume of the feed. However, a reduction can also be achieved by changing the geometry of the shaped catalyst bodies obtainable in accordance with the invention such that the amount of active composition contained in the unit of the inner volume of the reaction tube becomes smaller.

For the heterogeneously catalyzed gas phase partial oxidations with annular unsupported catalyst bodies of the invention obtainable as described, the catalyst feed is preferably either uniformly formed along the entire length with only one type of unsupported catalyst ring bodies or structured as follows. At the reactor inlet is at a length of 10 to 60%, preferably 10 to 50%, more preferably 20 to 40% and most preferably 25 to 35% (ie, for., On a length of 0.70 to 1.50 m, preferably 0.90 to 1.20 m), in each case the total length of the catalyst charge, a substantially homogeneous mixture of annular unsupported catalyst shaped body obtainable according to the invention and inert dilution molded body (both preferably having substantially the same geometry), the weight fraction of the dilution molded bodies (The mass densities of shaped catalyst bodies and of shaped diluents usually differ only slightly) normally from 5 to 40% by weight, or from 10 to 40% by weight, or from 20 to 40% by weight, or from 25 to 35% by weight. % is. In connection to This first feed section is then advantageously up to the end of the length of the catalyst feed (ie, for example, to 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 a diluted only to a lesser extent (as in the first section) bed of the invention as available obtainable annular Vollkatalysatorformkörpers, or, most preferably, a sole (undiluted) bed of the same invention annular Vollkatalysatorformkörpers that has been used in the first section. Of course, a constant dilution can be selected throughout the feed. Also, in the first section only with an inventively available annular Vollkatalysatorformkörper of low, based on its space requirement, active mass density and in the second section with an inventively available annular Vollkatalysatorformkörper with high, based on its space requirement, active mass density can be charged (eg 6.5 mm × 3 mm × 4.5 mm [A × H × I] in the first section, and 5 × 2 × 2 mm in the second section).

In the case of a partial oxidation according to the invention (eg ring-shaped) catalyst bodies which are carried out as catalysts for the preparation of acrolein or methacrolein, the catalyst charge, the reaction gas starting mixture, the load and the reaction temperature are generally chosen such that during the single pass of the catalyst Reaction gas mixture through the catalyst feed a conversion of the partially oxidized organic compound (propene, isobutene, tert-butanol or its methyl ether) of at least 90 mol%, or at least 92 mol%, preferably of at least 94 mol% results , The selectivity of acrolein or methacrolein formation will be regularly ≥ 80 mol%, or ≥ 85 mol%. In the natural way, the lowest possible hotspot temperatures are sought.

Finally, it should be noted that as described inventive annular Vollkatalysatorformkörper also have an advantageous fracture behavior in the reactor filling.

The commissioning of a (s) fresh, according to the invention available geometric shaped catalyst body containing, catalyst charge (fixed catalyst bed) can, for. B. as in the DE-A 103 37 788 or as in the DE-A 102009047291 described described.

The formation of geometric shaped catalyst bodies obtainable according to the invention can be accelerated by carrying them out at substantially constant conversion under increased loading of the catalyst charge with reaction gas input mixture.

Incidentally, multimetal oxide compositions of the general stoichiometry I according to the invention and catalysts containing them as active composition are quite generally suitable for catalyzing the gas phase partial oxidation of an alkanol, alkanal, alkene, alkane and alkenalene containing 3 to 6 (ie, 3, 4, 5 or 6) carbon atoms for example olefinically unsaturated aldehydes and / or carboxylic acids and the corresponding nitriles, and suitable for gas phase catalytic oxidative dehydrogenation of the aforementioned 3, 4, 5 or 6 C-containing organic compounds.

The large-scale production of annular unsupported catalyst bodies according to the invention is carried out appropriately in terms of application technology, as in the German Offenlegungsschriften DE-A 102008040093 and DE-A 102008040094 described.

• 1. Mo, Bi und Fe enthaltende Multimetalloxidmassen der allgemeinen Stöchiometrie I, Mo₁₂ Bi_a Co_b Fe_c K_d Si_e O_x (I), in der die Variablen folgende Bedeutung haben: a = 0,5 bis 1, b = 7 bis 8,5, c = 1,5 bis 3,0, d = 0 bis 0,15, e = 0 bis 2,5 und x = eine Zahl, die durch die Wertigkeit und Häufigkeit der von Sauerstoff verschiedenen Elemente in I bestimmt wird, und die folgenden Bedingungen erfüllen: Bedingung 1 : 12 – b – 1,5·c = A, und 0,5 ≤ A ≤ 1,5; Bedingung 2 : 0,2 ≤ a/A ≤ 1,3; und Bedingung 3 : 2,5 ≤ b/c ≤ 9.
• 2. Multimetalloxidmasse gemäß Ausführungsform 1, deren stöchiometrischer Koeffizient d 0,04 bis 0,1 beträgt.
• 3. Multimetalloxidmasse gemäß Ausführungsform 1 oder 2, deren stöchiometrischer Koeffizient d 0,05 bis 0,08 beträgt.
• 4. Multimetalloxidmasse gemäß einer der Ausführungsformen 1 bis 3, deren stöchiometrischer Koeffizient e 0,5 bis 2 beträgt.
• 5. Multimetalloxidmasse gemäß einer der Ausführungsformen 1 bis 4, deren stöchiometrischer Koeffizient e 0,8 bis 1,8 beträgt.
• 6. Multimetalloxidmasse gemäß einer der Ausführungsformen 1 bis 5, deren stöchiometrischer Koeffizient e 1 bis 1,6 beträgt.
• 7. Multimetalloxidmasse gemäß einer der Ausführungsformen 1 bis 6, die die Bedingung 1, 0,5 ≤ A ≤ 1,25, erfüllt.
• 8. Multimetalloxidmasse gemäß einer der Ausführungsformen 1 bis 7, die die Bedingung 1, 0,5 ≤ A ≤ 1, erfüllt.
• 9. Multimetalloxidmasse gemäß einer der Ausführungsformen 1 bis 8, die die Bedingung 2, 0,3 ≤ a/A ≤ 1,2, erfüllt.
• 10. Multimetalloxidmasse gemäß einer der Ausführungsformen 1 bis 9, die die Bedingung 2, 0,4 ≤ a/A ≤ 1,2, erfüllt.
• 11. Multimetalloxidmasse gemäß einer der Ausführungsformen 1 bis 10, die die Bedingung 2, 0,5 ≤ a/A ≤ 1,2, erfüllt.
• 12. Multimetalloxidmasse gemäß einer der Ausführungsformen 1 bis 11, die die Bedingung 3, 3 ≤ b/c ≤ 9, erfüllt.
• 13. Multimetalloxidmasse gemäß einer der Ausführungsformen 1 bis 12, die die Bedingung 3, 3 ≤ b/c ≤ 7, erfüllt.
• 14. Multimetalloxidmasse gemäß einer der Ausführungsformen 1 bis 13, die die Bedingung 3, 3 ≤ b ≤ 5, erfüllt.
• 15. Multimetalloxidmasse gemäß einer der Ausführungsformen 1 bis 14, deren spezifische Oberfläche 2 bis 20 m²/g beträgt.
• 16. Multimetalloxidmasse gemäß einer der Ausführungsformen 1 bis 15, deren spezifische Oberfläche 2 bis 15 m²/g beträgt.
• 17. Multimetalloxidmasse gemäß einer der Ausführungsformen 1 bis 16, deren spezifische Oberfläche 3 bis 10 m²/g beträgt.
• 18. Multimetalloxidmasse gemäß einer der Ausführungsformen 1 bis 17, deren spezifische Oberfläche 4 bis 8 m²/g beträgt.
• 19. Multimetalloxidmasse gemäß einer der Ausführungsformen 1 bis 18, deren Porengesamtvolumen 0,1 bis 1 cm³/g beträgt.
• 20. Multimetalloxidmasse gemäß einer der Ausführungsformen 1 bis 19, deren Porengesamtvolumen 0,1 bis 0,8 cm³/g beträgt.
• 21. Multimetalloxidmasse gemäß einer der Ausführungsformen 1 bis 20, deren Porengesamtvolumen 0,1 bis 0,5 cm³/g beträgt.
• 22. Multimetalloxidmasse gemäß einer der Ausführungsformen 1 bis 21, deren Porengesamtvolumen 0,2 bis 0,4 cm³/g beträgt.
• 23. Multimetalloxidmasse gemäß einer der Ausführungsformen 1 bis 22, bei der der Beitrag von Poren mit einem Porenradius ≤ 0,1 µm zum Porengesamtvolumen ≤ 0,05 cm³/g beträgt.
• 24. Multimetalloxidmasse gemäß einer der Ausführungsformen 1 bis 23, bei der der Beitrag von Poren mit einem Porenradius im Bereich von 0,2 bis 0,4 µIm zum Porengesamtvolumen, bezogen auf das Porengesamtvolumen, ≥ 70 Vol.-% beträgt.
• 25. Multimetalloxidmasse gemäß einer der Ausführungsformen 1 bis 24, bei der der Beitrag von Poren mit einem Porenradius im Bereich von 0,2 bis 0,4 µm zum Porengesamtvolumen, bezogen auf das Porengesamtvolumen, ≥ 75 Vol.-% beträgt.
• 26. Multimetalloxidmasse gemäß einer der Ausführungsformen 1 bis 25, bei der der Beitrag von Poren mit einem Porenradius im Bereich von 0,2 bis 0,4 µm zum Porengesamtvolumen, bezogen auf das Porengesamtvolumen, ≥ 85 Vol.-% beträgt.
• 27. Multimetalloxidmasse gemäß einer der Ausführungsformen 1 bis 26, bei der der Beitrag von Poren mit einem Porenradius im Bereich von 0,2 bis 0,4 µm zum Porengesamtvolumen, bezogen auf das Porengesamtvolumen, ≥ 90 Vol.-% beträgt.
• 28. Multimetalloxidmasse gemäß einer der Ausführungsformen 1 bis 27, bei der der Beitrag von Poren mit einem Porenradius im Bereich von 0,2 bis 0,4 µm zum Porengesamtvolumen, bezogen auf das Porengesamtvolumen, ≥ 95 Vol.-% beträgt.
• 29. Multimetalloxidmasse gemäß einer der Ausführungsformen 1 bis 28, bei der bei einer Auftragung ihrer Porendurchmesser in µm auf der Abszisse und des Logarithmus des differentiellen Beitrags in cm³/g des jeweiligen Porendurchmessers zum Porengesamtvolumen in cm³/g auf der Ordinate eine monomodale Verteilungskurve resultiert.
• 30. Schalenkatalysator, umfassend einen Trägerformkörper und eine auf der äußeren Oberfläche des Trägerformkörpers befindliche Schale aus wenigstens einer Multimetalloxidmasse gemäß einer der Ausführungsformen 1 bis 29.
• 31. Schalenkatalysator gemäß Ausführungsform 30, bei dem die Schale aus der wenigstens einen Multimetalloxidmasse eine Dicke von 10 bis 1000 µm aufweist.
• 32. Schalenkatalysator gemäß Ausführungsform 30 oder 31, bei dem die Schale aus der wenigstens einen Multimetalloxidmasse eine Dicke von 100 bis 700 µm aufweist.
• 33. Schalenkatalysator gemäß einer der Ausführungsformen 30 bis 32, bei dem die Schale aus der wenigstens einen Multimetalloxidmasse eine Dicke von 300 bis 500 µm aufweist.
• 34. Schalenkatalysator gemäß einer der Ausführungsformen 30 bis 33, dessen Trägerformkörper eine Kugel, ein Vollzylinder oder ein Hohlzylinder ist.
• 35. Schalenkatalysator gemäß Ausführungsform 34, dessen Trägerformkörper eine Kugel ist, deren Durchmesser 1 bis 8 mm beträgt.
• 36. Schalenkatalysator gemäß Ausführungsform 34, dessen Trägerformkörper ein Zylinder ist, dessen Länge 2 bis 10 mm und dessen Außendurchmesser 4 bis 10 mm beträgt.
• 37. Schalenkatalysator gemäß Ausführungsform 34, dessen Trägerformkörper ein Ring mit einer Wanddicke von 1 bis 4 mm, einer Länge von 2 bis 10 mm und einem Außendurchmesser von 4 bis 10 mm ist.
• 38. Schalenkatalysator gemäß Ausführungsform 37, dessen Trägerformkörper ein Ring mit einer Wanddicke von 1 bis 2 mm, einer Länge von 3 bis 6 mm und einem Außendurchmesser von 4 bis 8 mm ist.
• 39. Schalenkatalysator gemäß Ausführungsform 37, dessen Trägerformkörper ein Ring mit einer Wanddicke von 1 bis 2 mm, einer Länge von 2 bis 4 mm und einem Außendurchmesser von 4 bis 8 mm ist.
• 40. Schalenkatalysator gemäß einer der Ausführungsformen 30 bis 39, wobei das Material des Trägerformkörpers Aluminiumoxid, Siliciumdioxid, ein Silikat, Siliciumcarbid, Zirkondioxid, Thoriumdioxid oder Steatit ist.
• 41. Vollkatalysatorformkörper, dessen Aktivmasse wenigstens ein Multimetalloxid gemäß einer der Ausführungsformen 1 bis 29 ist.
• 42. Vollkatalysatorformkörper gemäß Ausführungsform 41, der die Geometrie einer Kugel, eines Zylinders oder eines Ringes aufweist.
• 43. Vollkatalysatorformkörper gemäß Ausführungsform 42, der die Geometrie einer Kugel mit einem Durchmesser von 2 bis 10 mm aufweist.
• 44. Vollkatalysatorformkörper gemäß Ausführungsform 43, dessen Kugeldurchmesser 4 bis 8 mm beträgt.
• 45. Vollkatalysatorformkörper gemäß Ausführungsform 42, der die Geometrie eines Zylinders mit einer Länge von 2 bis 10 mm und einem Außendurchmesser von 2 bis 10 mm aufweist.
• 46. Vollkatalysatorformkörper gemäß Ausführungsform 45, wobei die Länge 2 bis 8 mm und der Außendurchmesser 2 bis 8 mm beträgt.
• 47. Vollkatalysatorformkörper gemäß Ausführungsform 42, der die Geometrie eines Ringes mit einer Wanddicke von 1 bis 3 mm, einer Länge von 2 bis 10 mm und einem Außendurchmesser von 2 bis 10 mm aufweist.
• 48. Vollkatalysatorformkörper gemäß Ausführungsform 47, dessen Länge 2 bis 8 mm und dessen Außendurchmesser 3 bis 8 mm beträgt.
• 49. Vollkatalysatorformkörper gemäß Ausführungsform 47, dessen Länge 3 bis 8 mm und dessen Außendurchmesser 3 bis 8 mm beträgt.
• 50. Vollkatalysatorformkörper gemäß einer der Ausführungsformen 47 bis 49, bei dem das Verhältnis von Länge zu Außendurchmesser 0,3 bis 0,7 beträgt.
• 51. Vollkatalysatorformkörper gemäß Ausführungsform 50, bei dem das Verhältnis von Länge zu Außendurchmesser 0,4 bis 0,6 beträgt.
• 52. Vollkatalysatorformkörper gemäß einer der Ausführungsformen 47 bis 51, bei dem das Verhältnis von Innendurchmesser zu Außendurchmesser 0,3 bis 0,7 beträgt.
• 53. Vollkatalysatorformkörper gemäß Ausführungsform 52, bei dem das Verhältnis von Innendurchmesser zu Außendurchmesser 0,4 bis 0,7 beträgt.
• 54. Vollkatalysatorformkörper gemäß Ausführungsform 47, dessen Ringgeometrie mit Außendurchmesser × Länge × Innendurchmesser eine Ringgeometrie aus der Gruppe 5 mm × 2 mm × 2 mm, 5 mm × 3 mm × 2 mm, 5 mm × 3 mm × 3 mm, 5,5 mm × 3 mm × 3,5 mm, 6 mm × 3 mm × 4 mm, 6,5 mm × 3 mm × 4,5 mm, 7 mm × 3 mm × 5 mm, 7 mm × 7 mm × 3 mm, 7 mm × 3 mm × 4 mm, und 7 mm × 7 mm × 4 mm ist.
• 55. Verfahren zur Herstellung einer Multimetalloxidmasse gemäß einer der Ausführungsformen 1 bis 29, dadurch gekennzeichnet, dass man von Quellen ihrer elementaren Konstituenten ein feinteiliges inniges Trockengemisch erzeugt und dieses bei Temperaturen im Bereich von 350 bis 650 °C kalciniert.
• 56. Verfahren gemäß Ausführungsform 55, dadurch gekennzeichnet, dass die Kalcination unter Inertgas, unter einem Gemisch aus molekularem Sauerstoff und einem Inertgas, unter einer reduzierenden Atmosphäre oder unter Vakuum erfolgt.
• 57. Verfahren gemäß Ausführungsform 56, dadurch gekennzeichnet, dass die Kalcination unter Luft erfolgt.
• 58. Verfahren gemäß einer der Ausführungsformen 55 bis 57, dadurch gekennzeichnet, dass die Quellen in Form von Lösungen und/oder Suspensionen miteinander vermischt und die dabei resultierende nasse Mischung M zum feinteiligen innigen Trockengemisch getrocknet wird.
• 59. Verfahren gemäß Ausführungsform 58, dadurch gekennzeichnet, dass das Lösungsund/oder Suspendiermittel eine wässrige Lösung ist.
• 60. Verfahren gemäß Ausführungsform 58 oder 59, dadurch gekennzeichnet, dass als Quellen nur Lösungen und/oder kolloidale Lösungen verwendet werden.
• 61. Verfahren gemäß Ausführungsform 60, dadurch gekennzeichnet, dass eine Quelle eine wässrige Lösung A ist, die Ausgangsverbindungen der Elemente Co, Fe und Bi gelöst enthält und deren pH-Wert ≤ 3 und ≥ –2 beträgt.
• 62. Verfahren gemäß Ausführungsform 60 oder 61, dadurch gekennzeichnet, dass eine Quelle eine wässrige Lösung B ist, die Ausgangsverbindungen der Elemente K und Mo gelöst enthält und deren pH-Wert ≤ 6,5 und ≥ 3 ist.
• 63. Verfahren gemäß einer der Ausführungsformen 60 bis 62, dadurch gekennzeichnet, dass eine Quelle wässriges Kieselsol ist.
• 64. Verfahren gemäß einer der Ausführungsformen 55 bis 63, dadurch gekennzeichnet, dass im Rahmen der Herstellung des feinteiligen innigen Trockengemischs eine wässrige Lösung A, die Ausgangsverbindungen der Elemente Co, Fe und Bi gelöst enthält und deren pH-Wert ≤ 3 und ≥ –2 beträgt, mit einer wässrigen Lösung B, die Ausgangsverbindungen der Elemente K und Mo gelöst enthält und deren pH-Wert ≤ 6,5 und ≥ 3 ist, vermischt wird und in das resultierende wässrige Gemisch ein wässriges Kieselsol eingemischt wird, wobei eine wässrige Mischung M resultiert.
• 65. Verfahren gemäß Ausführungsform 64, dadurch gekennzeichnet, dass die wässrige Lösung A in die wässrige Lösung B eingerührt wird.
• 66. Verfahren gemäß Ausführungsform 65, dadurch gekennzeichnet, dass das Einrühren bei einer Temperatur ≤ 80 °C und ≥ 0 °C erfolgt.
• 67. Verfahren gemäß Ausführungsform 66, dadurch gekennzeichnet, dass das Einrühren bei einer Temperatur ≤ 70 °C und ≥ 0 °C erfolgt.
• 68. Verfahren gemäß Ausführungsform 66 oder 67, dadurch gekennzeichnet, dass das Einrühren bei einer Temperatur ≤ 60 °C und ≥ 0 °C erfolgt.
• 69. Verfahren gemäß einer der Ausführungsformen 66 bis 68, dadurch gekennzeichnet, dass das Einrühren bei einer Temperatur ≤ 40 °C und ≥ 0 °C erfolgt.
• 70. Verfahren gemäß einer der Ausführungsformen 64 bis 69, dadurch gekennzeichnet, dass das Verhältnis V, gebildet aus der in der wässrigen Mischung der wässrigen Lösung A und der wässrigen Lösung B wahlweise enthaltenen molaren Gesamtmenge n₁ an NH₃ und NH₄ ⁺ und der in derselben wässrigen Mischung enthaltenen molaren Gesamtmenge n₂ an Mo, V = n₁ : n₂, ≤ 1 beträgt.
• 71. Verfahren gemäß Ausführungsform 70, dadurch gekennzeichnet, dass 0 ≤ V ≤ 6/7 ist.
• 72. Verfahren gemäß einer der Ausführungsformen 64 bis 71, dadurch gekennzeichnet, dass der pH-Wert der wässrigen Mischung aus der wässrigen Lösung A und der wässrigen Lösung B ≤ 3 und ≥ 0 beträgt.
• 73. Verfahren gemäß einer der Ausführungsformen 64 bis 72, dadurch gekennzeichnet, dass der SiO₂-Gehalt des wässrigen Kieselsols 15 bis 60 Gew.-% beträgt.
• 74. Verfahren gemäß einer der Ausführungsformen 64 bis 73, dadurch gekennzeichnet, dass der SiO₂-Gehalt des wässrigen Kieselsols 30 bis 60 Gew.-% beträgt.
• 75. Verfahren gemäß einer der Ausführungsformen 64 bis 74, dadurch gekennzeichnet, dass der SiO₂-Gehalt des wässrigen Kieselsols 45 bis 55 Gew.-% beträgt
• 76. Verfahren gemäß einer der Ausführungsformen 64 bis 75, dadurch gekennzeichnet, dass der Gesamtgehalt der wässrigen Mischung M an Mo, Co, Fe, Bi und Si, bezogen auf die Menge an in der wässrigen Mischung M enthaltenem Wasser, 5 bis 25 Gew.-% beträgt.
• 77. Verfahren gemäß Ausführungsform 76, dadurch gekennzeichnet, dass der Gesamtgehalt der wässrigen Mischung M an Mo, Co, Fe, Bi und Si, bezogen auf die Menge an in der wässrigen Mischung M enthaltenem Wasser, 8 bis 20 Gew.-% beträgt.
• 78. Verfahren gemäß einer der Ausführungsformen 64 bis 77, dadurch gekennzeichnet, dass der pH-Wert der wässrigen Mischung M ≤ 3 beträgt.
• 79. Verfahren gemäß Ausführungsform 78, dadurch gekennzeichnet, dass der pH-Wert der wässrigen Mischung M ≥ 0 und ≤ 2 beträgt.
• 80. Verfahren gemäß einer der Ausführungsformen 64 bis 79, dadurch gekennzeichnet, dass der im wässrigen Medium der wässrigen Mischung M gelöst vorliegende Anteil AT an Co der in der wässrigen Mischung M insgesamt enthaltenen Menge an Co ≤ 60 % beträgt.
• 81. Verfahren gemäß Ausführungsform 80, dadurch gekennzeichnet, dass AT ≤ 50 % beträgt. 82. Verfahren gemäß Ausführungsform 80 oder 81, dadurch gekennzeichnet, dass 15 % ≤ AT ≤ 40 % gilt.
• 83. Verfahren gemäß einer der Ausführungsformen 58 bis 82, dadurch gekennzeichnet, dass die Trocknung durch Sprühtrocknung erfolgt.
• 84. Verfahren gemäß Ausführungsform 83, dadurch gekennzeichnet, dass die Sprühtrocknung der wässrigen Mischung M nach Versprühen derselben in einem heißem Gasstrom erfolgt, dessen Eintrittstemperatur 250 bis 450 °C beträgt.
• 85. Verfahren gemäß einer der Ausführungsformen 55 bis 84, dadurch gekennzeichnet, dass man das innige Trockengemisch vorab der Kalcinierung, wahlweise unter Zusatz von Formgebungshilfsmitteln, zu Formkörpern von regelmäßiger oder unregelmäßiger Geometrie formt.
• 86. Verfahren gemäß Ausführungsform 85, dadurch gekennzeichnet, dass die Formgebung durch Tablettieren erfolgt.
• 87. Verfahren gemäß Ausführungsform 85 oder 86, dadurch gekennzeichnet, dass als Formgebungshilfsmittel Graphit zugesetzt wird.
• 88. Verfahren gemäß einer der Ausführungsformen 85 bis 87, dadurch gekennzeichnet, dass der Formkörper die Geometrie eines Ringes aufweist.
• 89. Verfahren gemäß Ausführungsform 88, dadurch gekennzeichnet, dass der Ring einen Außendurchmesser von 2 bis 10 mm, eine Höhe von 2 bis 10 mm und eine Wandstärke von 1 bis 3 mm aufweist.
• 90. Verfahren gemäß Ausführungsform 89, dadurch gekennzeichnet, dass der Ring einen Außendurchmesser von 2 bis 8 mm und eine Höhe von 2 bis 8 mm aufweist.
• 91. Verfahren gemäß Ausführungsform 89 oder 90, dadurch gekennzeichnet, dass der Ring einen Außendurchmesser von 3 bis 8 mm und eine Höhe von 3 bis 8 mm aufweist.
• 92. Verfahren gemäß einer der Ausführungsformen 88 bis 91, dadurch gekennzeichnet, dass die Seitendruckfestigkeit SD des ringförmigen Formkörpers die Relation 12 N ≤ SD ≤ 35 N erfüllt.
• 93. Verfahren gemäß Ausführungsform 92, dadurch gekennzeichnet, dass die Seitendruckfestigkeit die Relation 15 N ≤ SD ≤ 30 N erfüllt.
• 94. Verfahren gemäß Ausführungsform 92 oder 93, dadurch gekennzeichnet, dass die Seitendruckfestigkeit die Relation 19 N ≤ SD ≤ 30 N erfüllt.
• 95. Verfahren gemäß einer der Ausführungsformen 55 bis 94, dadurch gekennzeichnet, dass bei der Kalcination die Temperatur von 600 °C nicht überschritten wird.
• 96. Verfahren gemäß einer der Ausführungsformen 55 bis 95, dadurch gekennzeichnet, dass bei der Kalcination die Temperatur von 550 °C nicht überschritten wird.
• 97. Verfahren gemäß einer der Ausführungsformen 55 bis 96, dadurch gekennzeichnet, dass bei der Kalcination die Temperatur von 500 °C nicht überschritten wird.
• 98. Verfahren gemäß einer der Ausführungsformen 55 bis 97, dadurch gekennzeichnet, dass vorab der Kalcination eine thermische Behandlung des innigen Trockengemischs bei Temperaturen ≥ 120 °C und ≤ 350 °C erfolgt.
• 99. Verfahren gemäß einer der Ausführungsformen 55 bis 98, dadurch gekennzeichnet, dass vorab der Kalcination eine thermische Behandlung des innigen Trockengemischs bei Temperaturen ≥ 150 °C und ≤ 320 °C erfolgt.
• 100. Verfahren gemäß einer der Ausführungsformen 55 bis 99, dadurch gekennzeichnet, dass vorab der Kalcination eine thermische Behandlung des innigen Trockengemischs bei Temperaturen ≥ 220 °C und ≤ 290 °C erfolgt.
• 101. Verfahren der heterogen katalysierten partiellen Gasphasenoxidation eines 3 bis 6 C-Atome aufweisenden Alkans, Alkanols, Alkanals, Alkens und/oder Alkenals an einem Katalysatorbett, dadurch gekennzeichnet, dass das Katalysatorbett wenigstens eine Multimetalloxidmasse gemäß einer der Ausführungsformen 1 bis 29 aufweist.
• 102. Verfahren der heterogen katalysierten partiellen Gasphasenoxidation eines 3 bis 6 C-Atome aufweisenden Alkans, Alkanols, Alkanals, Alkens und/oder Alkenals an einem Katalysatorbett, dadurch gekennzeichnet, dass das Katalysatorbett wenigstens einen Katalysator gemäß einer der Ausführungsformen 30 bis 54 aufweist.
• 103. Verfahren der heterogen katalysierten partiellen Gasphasenoxidation eines 3 bis 6 C-Atome aufweisenden Alkans, Alkanols, Alkanals, Alkens und/oder Alkenals an einem Katalysatorbett, dadurch gekennzeichnet, dass das Katalysatorbett wenigstens ein Produkt eines Verfahrens gemäß einer der Ausführungsformen 55 bis 100 aufweist.
• 104. Verfahren gemäß einer der Ausführungsformen 101 bis 103, dadurch gekennzeichnet, dass es ein Verfahren der heterogen katalysierten partiellen Gasphasenoxidation von Propen zu Acrolein oder von iso-Buten zu Methacrolein ist.
• 105. Verfahren gemäß einer der Ausführungsformen 101 bis 103, dadurch gekennzeichnet, dass es ein Verfahren der Ammoxidation von Propen zu Acrylnitril oder ein Verfahren der Ammoxidation von iso-Buten zu Methacrylnitril ist.
• 106. Verwendung wenigstens eines Multimetalloxids gemäß einer der Ausführungsformen 1 bis 29, oder wenigstens eines Katalysators gemäß einer der Ausführungsformen 30 bis 54, oder wenigstens eines Produkts eines Verfahrens gemäß einer der Ausführungsformen 55 bis 100 zur Katalyse eines Verfahrens der heterogen katalysierten partiellen Gasphasenoxidation eines 3 bis 6 C-Atome aufweisenden Alkans, Alkanols, Alkanals, Alkens und/oder Alkenals an einem Katalysatorbett.

Thus, the present application comprises in particular the following embodiments according to the invention:

• 1. Mo, Bi and Fe-containing multimetal oxide materials of general stoichiometry I, Mo ₁₂ Bi _a Co _b Fe _c K _d Si _e O _x (I), in which the variables have the following meaning: a = 0.5 to 1, b = 7 to 8.5, c = 1.5 to 3.0, d = 0 to 0.15, e = 0 to 2.5 and x = a number determined by the valence and frequency of the non-oxygen elements in I and satisfying the following conditions: Condition 1: 12-b-1.5 · c = A, and 0.5 ≤ A ≤ 1.5; Condition 2: 0.2 ≤ a / A ≤ 1.3; and condition 3: 2.5 ≦ b / c ≦ 9.
• 2. Multimetal oxide composition according to embodiment 1, whose stoichiometric coefficient d is 0.04 to 0.1.
• 3. Multimetal oxide composition according to embodiment 1 or 2, whose stoichiometric coefficient d is 0.05 to 0.08.
• 4. Multimetal oxide according to any one of embodiments 1 to 3, whose stoichiometric coefficient e is 0.5 to 2.
• 5. Multimetal oxide according to any one of embodiments 1 to 4, whose stoichiometric coefficient e is 0.8 to 1.8.
• 6. Multimetal oxide according to any of embodiments 1 to 5, whose stoichiometric coefficient e is 1 to 1.6.
• 7. The multimetal oxide composition according to any one of Embodiments 1 to 6 satisfying the condition 1, 0.5 ≦ A ≦ 1.25.
• 8. The multimetal oxide composition according to any one of Embodiments 1 to 7 which satisfies the condition 1, 0.5 ≦ A ≦ 1.
• 9. The multimetal oxide composition according to any one of Embodiments 1 to 8 satisfying Condition 2, 0.3 ≦ a / A ≦ 1.2.
• 10. The multimetal oxide composition according to any one of Embodiments 1 to 9 satisfying Condition 2, 0.4 ≦ a / A ≦ 1.2.
• 11. The multimetal oxide composition according to any one of Embodiments 1 to 10 satisfying Condition 2, 0.5 ≦ a / A ≦ 1.2.
• 12. The multimetal oxide composition according to any one of embodiments 1 to 11 satisfying the condition 3, 3 ≦ b / c ≦ 9.
• 13. The multimetal oxide composition according to any one of embodiments 1 to 12 satisfying the condition 3, 3 ≦ b / c ≦ 7.
• 14. The multimetal oxide composition according to any one of embodiments 1 to 13 satisfying the condition 3, 3 ≦ b ≦ 5.
• 15. Multimetal oxide according to any of embodiments 1 to 14, whose specific surface is 2 to 20 m ² / g.
• 16. Multimetal oxide composition according to any one of embodiments 1 to 15, whose specific surface area is 2 to 15 m ² / g.
• 17. Multimetal oxide composition according to one of embodiments 1 to 16, whose specific surface area is 3 to 10 m ² / g.
• 18. Multimetal oxide composition according to any one of embodiments 1 to 17, whose specific surface area is 4 to 8 m ² / g.
• 19. Multimetal oxide composition according to one of embodiments 1 to 18, whose total pore volume is 0.1 to 1 cm ³ / g.
• 20. Multimetal oxide composition according to one of embodiments 1 to 19, whose total pore volume is 0.1 to 0.8 cm ³ / g.
• 21. Multimetal oxide composition according to one of embodiments 1 to 20, whose total pore volume is 0.1 to 0.5 cm ³ / g.
• 22. Multimetal oxide composition according to one of embodiments 1 to 21, whose total pore volume is 0.2 to 0.4 cm ³ / g.
• 23. Multimetal oxide composition according to any one of embodiments 1 to 22, wherein the contribution of pores having a pore radius ≤ 0.1 microns to the total pore volume ≤ 0.05 cm ³ / g.
• 24. Multimetal oxide composition according to one of embodiments 1 to 23, in which the contribution of pores having a pore radius in the range from 0.2 to 0.4 μm to the total pore volume, based on the total pore volume, is ≥70% by volume.
• 25. Multimetal oxide composition according to one of embodiments 1 to 24, wherein the contribution of pores having a pore radius in the range of 0.2 to 0.4 microns to the total pore volume, based on the total pore volume, ≥ 75 vol .-%.
• 26. Multimetal oxide composition according to any one of embodiments 1 to 25, wherein the contribution of pores having a pore radius in the range of 0.2 to 0.4 microns to the total pore volume, based on the total pore volume, ≥ 85 vol .-%.
• 27. Multimetal oxide composition according to one of embodiments 1 to 26, wherein the contribution of pores having a pore radius in the range of 0.2 to 0.4 microns to the total pore volume, based on the total pore volume, ≥ 90 vol .-%.
• 28. The multimetal oxide composition according to any one of embodiments 1 to 27, wherein the contribution of pores having a pore radius in the range of 0.2 to 0.4 microns to the total pore volume, based on the total pore volume, ≥ 95 vol .-%.
• 29. Multimetal oxide composition according to one of the embodiments 1 to 28, wherein in a plot of their pore diameter in microns on the abscissa and the logarithm of the differential contribution in cm ³ / g of the respective pore diameter to the total pore volume in cm ³ / g on the ordinate a monomodal distribution curve results.
• 30. coated catalyst, comprising a carrier molding and a shell located on the outer surface of the carrier molding of at least one Multimetalloxidmasse according to one of the embodiments 1 to 29th
• 31. coated catalyst according to embodiment 30, wherein the shell of the at least one Multimetalloxidmasse has a thickness of 10 to 1000 microns.
• 32. coated catalyst according to embodiment 30 or 31, wherein the shell of the at least one Multimetalloxidmasse has a thickness of 100 to 700 microns.
• 33. The coated catalyst according to one of embodiments 30 to 32, wherein the shell of the at least one multimetal oxide composition has a thickness of 300 to 500 μm.
• 34. coated catalyst according to one of the embodiments 30 to 33, the carrier molding is a ball, a solid cylinder or a hollow cylinder.
• 35. coated catalyst according to embodiment 34, the carrier molding is a ball whose diameter is 1 to 8 mm.
• 36. coated catalyst according to embodiment 34, the carrier molding is a cylinder whose length is 2 to 10 mm and whose outer diameter is 4 to 10 mm.
• 37. coated catalyst according to embodiment 34, the support molding is a ring with a wall thickness of 1 to 4 mm, a length of 2 to 10 mm and an outer diameter of 4 to 10 mm.
• 38. coated catalyst according to embodiment 37, the support molding is a ring with a wall thickness of 1 to 2 mm, a length of 3 to 6 mm and an outer diameter of 4 to 8 mm.
• 39. coated catalyst according to embodiment 37, the support molding is a ring with a wall thickness of 1 to 2 mm, a length of 2 to 4 mm and an outer diameter of 4 to 8 mm.
• 40. coated catalyst according to any of embodiments 30 to 39, wherein the material of the carrier molded body alumina, silica, a silicate, silicon carbide, zirconia, thoria or steatite.
• 41. An unsupported catalyst body whose active composition is at least one multimetal oxide according to one of embodiments 1 to 29.
• 42. The full catalyst shaped body according to embodiment 41, which has the geometry of a ball, a cylinder or a ring.
• 43. An all-catalyst shaped body according to embodiment 42, which has the geometry of a ball with a diameter of 2 to 10 mm.
• 44. Whole catalyst shaped body according to embodiment 43, whose ball diameter is 4 to 8 mm.
• 45. An all-catalyst shaped body according to embodiment 42, which has the geometry of a cylinder with a length of 2 to 10 mm and an outer diameter of 2 to 10 mm.
• 46. The unsupported catalyst body according to embodiment 45, wherein the length is 2 to 8 mm and the outer diameter is 2 to 8 mm.
• 47. The unsupported catalyst body according to embodiment 42, which has the geometry of a ring with a wall thickness of 1 to 3 mm, a length of 2 to 10 mm and an outer diameter of 2 to 10 mm.
• 48. An unsupported catalyst body according to embodiment 47, whose length is 2 to 8 mm and whose outer diameter is 3 to 8 mm.
• 49. An unsupported catalyst body according to embodiment 47, whose length is 3 to 8 mm and whose outer diameter is 3 to 8 mm.
• 50. An all-catalyst shaped body according to one of embodiments 47 to 49, wherein the ratio of length to outer diameter is 0.3 to 0.7.
• 51. An all-catalyst shaped body according to embodiment 50, wherein the ratio of length to outer diameter is 0.4 to 0.6.
• 52. An all-catalyst shaped body according to any one of embodiments 47 to 51, wherein the ratio of inner diameter to outer diameter is 0.3 to 0.7.
• 53. An all-catalyst shaped body according to embodiment 52, wherein the ratio of inner diameter to outer diameter is 0.4 to 0.7.
• 54. The unsupported catalyst body according to embodiment 47, whose outer diameter × length × inner diameter ring geometry has a ring geometry from the group 5 mm × 2 mm × 2 mm, 5 mm × 3 mm × 2 mm, 5 mm × 3 mm × 3 mm, 5.5 mm × 3 mm × 3.5 mm, 6 mm × 3 mm × 4 mm, 6.5 mm × 3 mm × 4.5 mm, 7 mm × 3 mm × 5 mm, 7 mm × 7 mm × 3 mm, 7 mm × 3 mm × 4 mm, and 7 mm × 7 mm × 4 mm.
• 55. A process for the preparation of a multimetal oxide according to any one of embodiments 1 to 29, characterized in that produced from sources of their elemental constituents a finely divided intimate dry mixture and calcined at temperatures ranging from 350 to 650 ° C.
• 56. The method according to embodiment 55, characterized in that the calcination is carried out under inert gas, under a mixture of molecular oxygen and an inert gas, under a reducing atmosphere or under vacuum.
• 57. The method according to embodiment 56, characterized in that the calcination takes place under air.
• 58. The method according to any one of embodiments 55 to 57, characterized in that the sources are mixed together in the form of solutions and / or suspensions and the resulting wet mixture M is dried to finely divided intimate dry mixture.
• 59. The method according to embodiment 58, characterized in that the solvent and / or suspending agent is an aqueous solution.
• 60. The method according to embodiment 58 or 59, characterized in that only solutions and / or colloidal solutions are used as sources.
• 61. Method according to embodiment 60, characterized in that a source is an aqueous solution A which contains dissolved starting compounds of the elements Co, Fe and Bi and whose pH is ≦ 3 and ≥ -2.
• 62. Method according to embodiment 60 or 61, characterized in that a source is an aqueous solution B which contains dissolved starting compounds of elements K and Mo and whose pH is ≤ 6.5 and ≥ 3.
• 63. The method according to any of embodiments 60 to 62, characterized in that a source is aqueous silica sol.
• 64. The method according to any one of embodiments 55 to 63, characterized in that within the production of the finely divided intimate dry mixture contains an aqueous solution A, the starting compounds of the elements Co, Fe and Bi dissolved and their pH ≤ 3 and ≥ -2 is mixed with an aqueous solution B containing starting compounds of the elements K and Mo dissolved and their pH ≤ 6.5 and ≥ 3 is mixed, and in the resulting aqueous mixture, an aqueous silica sol is mixed, wherein an aqueous mixture M results.
• 65. The method according to embodiment 64, characterized in that the aqueous solution A is stirred into the aqueous solution B.
• 66. The method according to embodiment 65, characterized in that the stirring takes place at a temperature ≤ 80 ° C and ≥ 0 ° C.
• 67. The method according to embodiment 66, characterized in that the stirring takes place at a temperature ≤ 70 ° C and ≥ 0 ° C.
• 68. The method according to embodiment 66 or 67, characterized in that the stirring takes place at a temperature ≤ 60 ° C and ≥ 0 ° C.
• 69. The method according to any one of embodiments 66 to 68, characterized in that the stirring takes place at a temperature ≤ 40 ° C and ≥ 0 ° C.
• 70. The method according to any one of embodiments 64 to 69, characterized in that the ratio V, formed from the molar total amount of n ₁ of NH ₃ and NH ₄ ⁺ optionally contained in the aqueous mixture of the aqueous solution A and the aqueous solution B. in the same aqueous mixture molar total amount of n ₂ to Mo, V = n ₁ : n ₂ , ≤ 1.
• 71. Method according to embodiment 70, characterized in that 0 ≤ V ≤ 6/7.
• 72. The method according to one of embodiments 64 to 71, characterized in that the pH of the aqueous mixture of the aqueous solution A and the aqueous solution B ≤ 3 and ≥ 0.
• 73. The method according to any one of embodiments 64 to 72, characterized in that the SiO ₂ content of the aqueous silica sol is 15 to 60 wt .-%.
• 74. The method according to any one of embodiments 64 to 73, characterized in that the SiO ₂ content of the aqueous silica sol is 30 to 60 wt .-%.
• 75. The method according to any one of embodiments 64 to 74, characterized in that the SiO ₂ content of the aqueous silica sol is 45 to 55 wt .-%
• 76. The method according to any one of embodiments 64 to 75, characterized in that the total content of the aqueous mixture M of Mo, Co, Fe, Bi and Si, based on the amount of water contained in the aqueous mixture M, 5 to 25 wt. -% is.
• 77. The method according to embodiment 76, characterized in that the total content of the aqueous mixture M of Mo, Co, Fe, Bi and Si, based on the amount of water contained in the aqueous mixture M, 8 to 20 wt .-% is.
• 78. The method according to any one of embodiments 64 to 77, characterized in that the pH of the aqueous mixture M ≤ 3.
• 79. Method according to embodiment 78, characterized in that the pH of the aqueous mixture is M ≥ 0 and ≤ 2.
• 80. The method according to any one of embodiments 64 to 79, characterized in that the proportion AT of Co dissolved in the aqueous medium of the aqueous mixture M is the total amount of Co ≤ 60% present in the aqueous mixture M.
• 81. Method according to embodiment 80, characterized in that AT ≤ 50%. 82. The method according to embodiment 80 or 81, characterized in that 15% ≤ AT ≤ 40% applies.
• 83. The method according to any one of embodiments 58 to 82, characterized in that the drying is carried out by spray drying.
• 84. The method according to embodiment 83, characterized in that the spray-drying of the aqueous mixture M after spraying thereof takes place in a hot gas stream whose inlet temperature is 250 to 450 ° C.
• 85. The method according to any one of embodiments 55 to 84, characterized in that forming the intimate dry mixture in advance of the calcination, optionally with the addition of shaping aids, to moldings of regular or irregular geometry.
• 86. The method according to embodiment 85, characterized in that the shaping is carried out by tableting.
• 87. The method according to embodiment 85 or 86, characterized in that graphite is added as a shaping aid.
• 88. The method according to any one of embodiments 85 to 87, characterized in that the shaped body has the geometry of a ring.
• 89. The method according to embodiment 88, characterized in that the ring has an outer diameter of 2 to 10 mm, a height of 2 to 10 mm and a wall thickness of 1 to 3 mm.
• 90. The method according to embodiment 89, characterized in that the ring has an outer diameter of 2 to 8 mm and a height of 2 to 8 mm.
• 91. The method according to embodiment 89 or 90, characterized in that the ring has an outer diameter of 3 to 8 mm and a height of 3 to 8 mm.
• 92. Method according to one of the embodiments 88 to 91, characterized in that the lateral compressive strength SD of the annular shaped body satisfies the relation 12 N ≦ SD ≦ 35 N.
• 93. Method according to embodiment 92, characterized in that the lateral compressive strength satisfies the relation 15 N ≤ SD ≤ 30 N.
• 94. The method according to embodiment 92 or 93, characterized in that the lateral compressive strength satisfies the relation 19 N ≤ SD ≤ 30 N.
• 95. The method according to any one of embodiments 55 to 94, characterized in that the temperature of 600 ° C is not exceeded in the Kalcination.
• 96. The method according to any one of embodiments 55 to 95, characterized in that the temperature of 550 ° C is not exceeded in the Kalcination.
• 97. The method according to any one of embodiments 55 to 96, characterized in that the temperature of 500 ° C is not exceeded in the Kalcination.
• 98. The method according to any one of embodiments 55 to 97, characterized in that prior to the Kalcination a thermal treatment of the intimate dry mixture at temperatures ≥ 120 ° C and ≤ 350 ° C.
• 99. The method according to any one of embodiments 55 to 98, characterized in that prior to the Kalcination a thermal treatment of the intimate dry mixture at temperatures ≥ 150 ° C and ≤ 320 ° C.
• 100. The method according to any one of embodiments 55 to 99, characterized in that prior to the Kalcination a thermal treatment of the intimate dry mixture at temperatures ≥ 220 ° C and ≤ 290 ° C.
• 101. A process of heterogeneously catalyzed partial gas phase oxidation of a 3 to 6 C-atoms alkane, alkanols, alkanal, alkenes and / or alkenals on a catalyst bed, characterized in that the catalyst bed has at least one multimetal oxide according to any of embodiments 1 to 29.
• 102. A process of heterogeneously catalyzed partial gas phase oxidation of a 3 to 6 C-atoms alkane, alkanols, alkanal, alkenes and / or alkenals on a catalyst bed, characterized in that the catalyst bed comprises at least one catalyst according to any one of embodiments 30 to 54.
• 103. A process of heterogeneously catalyzed partial gas phase oxidation of a 3 to 6 C-atoms alkane, alkanols, alkanal, alkenes and / or alkenals on a catalyst bed, characterized in that the catalyst bed comprises at least one product of a method according to any of embodiments 55 to 100 ,
• 104. A process according to any of embodiments 101 to 103, characterized in that it is a process of heterogeneously catalyzed partial gas phase oxidation of propene to acrolein or of isobutene to methacrolein.
• 105. A process according to any of embodiments 101 to 103, characterized in that it is a process of ammoxidation of propene to acrylonitrile or a process of ammoxidation of isobutene to methacrylonitrile.
• 106. Use of at least one multimetal oxide according to one of embodiments 1 to 29, or at least one catalyst according to one of embodiments 30 to 54, or at least one product of a process according to one of embodiments 55 to 100 for catalyzing a process of heterogeneously catalyzed partial gas phase oxidation of FIG alkanes, alkanols, alkanal, alkene and / or alkenalene having up to 6 carbon atoms on a catalyst bed.

Examples and Comparative Examples

I. Applied process for the preparation of annular unsupported catalyst bodies B1 to B4 and also V1 to V7

1. Preparation of the respective aqueous solution B

In a to the atmosphere (1 atm, 1.01 bar) open, tempered and equipped with an anchor stirrer vessel made of stainless steel (inner volume = 10 dm ³ ) was presented in Table 1 each listed amount of M1 in demineralized water and stirring (150 Rpm) to 60 ° C. Subsequently, the amount of M2 of a 32% by weight aqueous solution of KOH in water, which had a temperature of 60 ° C., listed in Table 1, was added in each case. After stirring at 60 ° C. for 1 minute, while maintaining the 60 ° C., the amount of M 3 of ammonium heptamolybdate tetrahydrate listed in Table 1 (white crystals with a particle size d <1 mm, 55% by weight Mo, 7.0-8, 5% by weight of NH ₃ , at most 150 mg / kg of alkali metals, from HC Starck, D-38642 Goslar) was stirred in portions and the resulting aqueous solution was stirred at 60 ° C. for 20 minutes (150 rpm). Subsequently, the amount M4 of ammonium paratungstate (71% by weight, HC Starck, D-38642 Goslar) listed in Table 1 was added and the mixture was stirred at 60 ° C. and 150 rpm for a further 20 minutes. The pH of each case resulting aqueous solution B was in the range 4 to 6.

2. Preparation of the respective aqueous solution A

In a stainless steel container (inner volume = 5 dm ³ ) open to the atmosphere (1 atm, 1.01 bar), temperature-controllable and equipped with an anchor stirrer, the amount of M5 listed in Table 1 was in each case an aqueous cobalt (II) nitrate solution (12.4 wt.% Co, 27 wt.% Nitrate (NO ₃ ^- )), pH = 1, prepared by dissolving cobalt metal from MFT Metals & Ferro-Alloys Trading GmbH, D-41474 Viersen, purity > 99.6 wt .-% Co, <0.3 wt .-% Ni, <100 mg / kg Fe, <50 mg / kg of Cu in nitric acid) and with stirring (150 U / min) to 60 ° C. heated. With continued stirring (150 rpm) and continued heating to 60 ° C., the amount M6 of crystalline iron (III) nitrate nonahydrate listed in Table 1 (13.6% by weight Fe, <0.4% by weight) was determined. % Of alkali metals, <0.01% by weight of chloride, <0.02% by weight of sulfate, from Dr. Paul Lohmann GmbH, D-81857 Emmerthal) and stirred at 60 ° C. for 10 minutes. To the resulting aqueous solution was in each case listed in Table 1 amount M7 of a 60 ° C warm, aqueous, nitrate Bismutnitratlösung (10.8 wt .-% Bi, 13 wt .-% nitrate, prepared by dissolving bismuth metal Fa. Sidech SA, BE-1495 Tilly, purity> 99.997% by weight of Bi, <7 mg / kg of Pb, <5 mg / kg each of Ni, Ag, Fe, <3 mg / kg Cu, Sb and <1 mg / kg each Cd, Zn in nitric acid) and stirred at 60 ° C for 10 min. The pH of each resulting aqueous solution A was in the range of -1 to 0.

3. Mixing of the respective aqueous solution A with the respective aqueous solution B

The respective 60 ° C warm aqueous solution A was using a peristaltic pump (type: BVP, company: Ismatec SA, laboratory technology analysis, Feldeggstraße 6, CH-8152 Glattbrugg, setting: 320 scale parts) within 15 min continuously in the now with an Ultra-Turrax (Janke & Kunkel GmbH & Co. KG - IKA-Labortechnik, Janke & Kunkel-Str. DE-79219 Staufen, stem type: 550KR-G45 fine, stem tube diameter: 25 mm, stator diameter: 45 mm, rotor diameter: 40 mm, setting: stage 5) metered intensively stirred 60 ° C warm respective aqueous solution B. The task of the aqueous solution A was carried out at the height of the rotor of the Ultra-Turax stirrer offset by about 0.5 to 1 cm from the outer edge of the rotor of the Ultra-Turax stirrer. The resulting aqueous suspension was stirred for a further 15 minutes at 60.degree.

4. Addition of a silica gel to obtain the respective aqueous mixture M

Subsequently, the aqueous mixture respectively obtained in "3." was in each case listed in Table 1 the amount M8 of a silica gel heated to 60 ° C. from Grace of the type Ludox TM50 (24.4% by weight of Si, density: 1.29 g / cm ³ , pH: 8.5 to 9.5, alkali content max 0.5 wt .-%) was added and then stirred for a further 15 min at 60 ° C. The pH of each resulting aqueous mixture M was in the range of 1 to 2 (in the case of the Vollkatalysatorformkörper V1, V2, V3, V4, V6 and V7 and B1 and B3) and in the range of 0 to 1 (in the case of Vollkatalysatorformkörper B2, B4 and V5).

The solids content of the various aqueous mixtures M obtained (the term solid subsumes the mass which has not been additionally dried, which precipitates as solid sediment in the centrifugation described below: Universal centrifuge 16 from Hettich, rotational speed: 3000 rpm, centrifugation time: 10 min , Use of centrifuge tubes with 100 ml filling volume, reference temperature: 60 ° C), based on the weight of the respective aqueous mixture M, in the range of 20 to 40 wt .-% (in the case of the Vollkatalysatorformkörper V1, V2, V3, V4, V6 and V7 and B1 and B3) or in the range of 40 to 60 wt .-% (in the case of the Vollkatalysatorformkörper B2, B4 and V5). The liquid supernatant contained, based on the total amount of cobalt present in the respective aqueous mixture M, 60 to 90% by weight of Co (in the case of the all-catalyst moldings V1, V2, V3, V4, V6 and V7 as well as B1 and B3) or 40 to 60 wt .-% of Co dissolved (in the case of Vollkatalysatorformkörper B2, B4 and V5). The separation of sediment and supernatant was carried out by decantation.

5. Spray drying of the particular aqueous mixture M

The respective aqueous mixture (suspension) M which was further stirred (also during the spray drying) at 60 ° C. by means of the anchor stirrer (150 rpm) was blown in a spray tower of the type Mobile Minor ™ 2000 (MM-I) from Niro A / S, Gladsaxevej 305, 2860 Søborg, Denmark, spray-dried within 90 to 140 minutes using a F01A centrifugal atomizer and a SL24-50 atomizing impeller in hot-air direct current (gas inlet temperature: 350 ± 10 ° C, gas outlet temperature: 140 ± 5 ° C) , The not yet spray-dried portion was always stirred at 60 ° C. The setting of the atomizer wheel speed was 25,000 rpm. In each case about 700 g (in the case of Vollkatalysatorformkörper V1, V2, V3, V4, V6 and V7 and B1 and B3) or about 1100 g (in the case of Vollkatalysatorformkörper B2, B4 and V5) obtained on orange-brown spray powder , The residual moistures of the various spray powders (determination of the residual moisture by means of microwaves) ranged from 3 (in the case of the solid catalyst tablet B3) to 7.7 wt% (in each case based on the total weight of the respective spray powder). The loss on ignition of the various spray powders (3 hours at 600 ° C (powder temperature) under stagnant air glow) was <35 wt .-% in all cases.

A representative spray powder particle diameter distribution (dispersion pressure = 2 bar absolute) with d ₁₀ = 9 μm, d ₅₀ = 22 μm and d ₉₀ = 39 μm shows 1 (in the case of Vollkatalysatorformkörpers B3). The abscissa shows the respective particle diameter (μm) on a logarithmic scale and the associated ordinate shows the percentage volume fraction of the spray powder (based on its total volume) which consists of particles of the respective diameter and particles of a smaller diameter (% by volume).

6. Preparation of annular unsupported catalyst precursor moldings (under N ₂ atmosphere)

In the respective spray powder were in a Rhönradmischer (wheel diameter: 650 mm, drum volume: 5 l), based on its weight, 1 wt .-% finely divided graphite variety TIMREX T44 from. Timcal Ltd., CH-6743 Bodio (cf. WO 2008/087116 ) homogeneously distributed (speed: 30 rpm, mixing time: 30 min). In a laboratory calender with 2 counter-rotating steel rollers (roll diameter: 10 cm, roller length used for intermediate compaction: 13.5 cm, roller speed: 10 rpm), the resulting homogeneous mixture was compacted at a pressure of 9 bar and then through a sieve with square mesh (edge length = 0.8 mm) pressed. In the respective, as described coarsened, spray powder were in the above-described Rhönradmischer (30 rev / min, 30 min mixing time), based on its weight, further 2.5 wt .-% of the same finely divided graphite mixed. Subsequently, the resulting finely divided intimate dry mixture as in DE-A 10200804093 described with a Kilian rotary (9-fold tableting machine) of the type S100 (Kilian, D-50735 Cologne) under a nitrogen atmosphere and an ambient temperature of 25 ° C to annular Vollkatalysatorvorläuferformkörpern the geometry A × H × I = 5 mm × 3 mm × 2 mm, a lateral compressive strength in the range 19 N to 30 N (in the case of the solid catalyst tablet B3 = 30 N) and a mass of 119 ± 2 mg compacted (tableted). The pressing force was 3.0 to 3.5 kN and the filling height was 7.5 to 9 mm.

7. Thermal pretreatment and calcining of the respective annular unsupported catalyst precursor moldings

For the final thermal treatment, in each case 1000 g of each prepared Vollkatalysatorvorläuferformkörper evenly distributed on juxtaposed 4 grids with a square base of 150 mm × 150 mm (height 15 mm) in a 4500 Nl / h previously dried air (the one inlet temperature circulating-air shaft furnace (Nabertherm, model S60 / 65A oven), through which the circulating-air oven was located in an environment having a temperature of 25.degree. Then, while maintaining the air flow (including its inlet temperature), the temperature in the circulating-air furnace was varied as follows (the temperature data mean the temperature in the bulk material applied, determined by 4 thermocouples located in the geometric center of the 4 grids in the center of the bulk one of the thermocouples provided the actual value for regulating the temperature of the convection oven, the other thermocouples confirmed that the temperatures were identical within the interval ± 0.1 ° C). The temperature increases were essentially linear over time. Within 72 min was heated from 25 ° C to 130 ° C. This temperature was maintained for 72 minutes and then increased to 190 ° C over 36 minutes. The 190 ° C was held for 72 minutes before the temperature was raised to 220 ° C over 36 minutes. The 220 ° C was held for 72 minutes before the temperature was increased to 265 ° C within 36 minutes. The 265 ° C was held for 72 minutes before the temperature was raised to 380 ° C over 93 minutes. The 380 ° C was held for 187 min before the temperature was increased to 430 ° C within 93 min. The 430 ° C was held for 187 min before increasing within 93 min to the final calcination temperature of 500 ° C. This was maintained 467 min. It was then cooled to 25 ° C within 12 h. For this purpose, both the heating of the Umluftschaftofens and the air flow preheating was switched off (the air flow of 4500 Nl / h as such was maintained, the inlet temperature of the air flow was then 25 ° C). The BET specific surface areas of the obtained unsupported annular shaped catalyst bodies were in the range of 4 to 8 m ² / g (in the case of the annular unsupported catalyst body B3, the BET specific surface area was 7.6 m ² / g).

2 shows the example of the Vollkatalysatorformkörpers B3 a representative XRD DIFF. The abscissa shows the diffraction angle in the 2Θ shell (2 theta scale) and the ordinate shows the absolute intensity of the diffracted X-radiation.

3 also shows the example of the Vollkatalysatorformkörpers B3 a representative pore distribution. On the abscissa, the pore diameter is plotted in microns. The logarithm of the differential contribution in cm ³ / g of the respective pore diameter to the total pore volume / g is plotted on the left ordinate. The maximum indicates the pore diameter with the largest contribution to the total pore volume. On the right ordinate in cm ³ / g the integral is plotted over the individual contributions of the individual pore diameters to the total pore volume / g. The end point is the total pore volume / g.

4 shows the example of the Vollkatalysatorformkörpers B3 a representative infrared transmission spectrum. On the abscissa the wavenumber is in cm ^-1 , on the ordinate the transmittance in% is plotted. The measuring instrument used was the Nicolet 6700 FTIR (Fourier Transformed Infrared) spectrometer from Thermo Fisher Scientific. The measurements were carried out after a trituration of the respective Vollkatalysatorformkörper with mortar and pestle (to particle sizes <0.1 mm), then from the respective trituration with the addition of finely divided KBr as an IR-inactive dilution material produced compacts. The associated measurement parameters were as follows: Resolution = 4 cm ^-1 ; Measuring range = 4000 to 400 cm ^-1 ; Number of scans = 32; Measurement type = transmission.

5 shows the example of the Vollkatalysatorformkörpers B3 a representative Raman spectrum. On the abscissa the Raman shift is in cm ^-1 , on the ordinate the associated Raman intensity is plotted. The Raman Microscope Alpha 300 R from the company WiTec was used as the measuring device. The measurement parameters in Raman spectroscopy were as follows: excitation wavelength of the laser: 532 nm; Grid: 600 grids / mm; Number of accumulations: 100; Integration time: 0.2 sec; used lens: the macro set with f = 30 mm. The measurements were carried out in each case on a trituration of the respective Vollkatalysatorformkörper to a particle size <0.1 mm with mortar and pestle.

6 shows the example of Vollkatalysatorformkörpers B3 a representative "pseudo" absorption spectrum in the wavelength range of 200 nm to 2126 nm. On the abscissa is the Kubelka-Munk absorption plotted on the ordinate the energy of the sample irradiating electromagnetic waves in eV. The Kubelka-Munk formalism (cf. P. Kubelka, F.Munk, Z.Tech.Phys. 1931, 12, p. 593 ff ) was used to convert the reflection measurement on the sample into a corresponding absorption spectrum. The UV / VIS / NIR spectrometer Lambda 900 with a 150 mm integrating sphere and the reference spectral white standard from Labsphere was used as the measuring device. The measurements were carried out in each case on a trituration of the respective Vollkatalysatorformkörper to a particle size <0.1 mm with mortar and pestle. The measurement parameters in UV / VIS / NIR spectroscopy were as follows: Data Interval: 1 nm; Gap width: 2.0 nm / NIR auto; UV / VIS integration time: 0.44 sec / NIR 0.44 sec; Measuring speed: 125 nm / min.

Table 2 shows the parameters A (condition 1), a / A (condition 2) and b / c (condition 3) determined for the various multimetal oxides of the annular unsupported catalyst bodies. Table 2 Unsupported catalyst bodies A a / A b / c B1 1 0.6 4.0 B2 1 0.6 4.0 B3 0.5 1.2 4.1 B4 0.5 1.2 4.1 V1 -0.15 -4 3.8 V2 1 0.1 4.0 V3 1 2 4.0 V4 0.5 1.2 2.3 V5 0.5 1.2 2.3 V6 0.5 1.2 1.0 V7 0.5 1.2 4.0

II. Catalysis of a heterogeneously catalyzed partial gas phase oxidation of propene to acrolein (main product) and acrylic acid (by-product) with the annular Vollkatalysatorformkörpern generated in I.

A reaction tube (V2A steel, 12 mm outer diameter, 3 mm wall thickness, 15 mm inner diameter, 120 cm length) was charged from top to bottom (in the later flow direction of the reaction gas mixture) as follows: Part 1: 30 cm in length 40 g steatite balls (steatite C220 from CeramTec) with a diameter of 1.5 to 2.0 mm as a pre-filling; Section 2: 70 cm in length Catalyst charge with 100 g of the respective ringförmi prepared in I. full catalyst.

The temperature control of the reaction tube was carried out in each case by means of a molecular nitrogen bubbled, the salt bath temperature T ^SB of 320 ° C having molten salt (53 wt .-% potassium nitrate, 40 wt .-% sodium nitrite and 7 wt .-% sodium nitrate). The salt bath (the molten salt) was in a cylindrical envelope of the inner diameter of 15 mm. The cylindrical envelope had the same length as the reaction tube. The latter was guided from top to bottom in the cylindrical envelope so that the two axes of symmetry coincided. The stream of nitrogen bubbled into the salt bath from below was 40 l / h (normal conditions = 1.01 bar, 0 ° C.). The heat losses of the salt bath to the environment were greater than the heat of reaction emitted by the tubular reactor during the partial oxidation to the salt bath. The salt bath was therefore kept at its temperature T ^SB (° C) by means of electrical heating. In this way it was ensured that the outer wall of the reaction tube always had the corresponding temperature T ^SB (° C).

The reaction tube was continuously charged with a reaction gas input mixture having the following composition:
5 vol.% Propene (grade of polymer grade)
9.5% by volume of molecular oxygen, and
85.5% by volume of molecular nitrogen.

The current strength of the reaction gas input mixture stream was in each case adjusted so that the propene conversion, based on a single pass of the reaction gas input mixture through the reaction tube, at the salt bath temperature T ^SB = 320 ° C., was 95 mol%. The pressure at the inlet to the reaction tube was in all cases 1.2 bar absolute (at the reaction tube outlet was located to the inlet pressure setting a relevant control valve).

Table 3 shows for the various unsupported catalyst bodies the propene loading PL of the fixed catalyst bed (here in Nl propene / (100 g unsupported catalyst body · h), which was compatible with the propene conversion requirement, and the total target product selectivity (S ^{AC + AS} (mol -%)) of total value product formation on acrolein (AC) and on acrylic acid (AS) Unsupported catalyst bodies PL (NL / 100 gh) S ^{AC + AS} (mol%) B1 9 96.8 B2 7 96.5 B3 10 97.0 B4 8.5 96.5 V1 10 95.5 V2 6 96.0 V3 10 94.9 V4 7 95.9 V5 5.5 95.8 V6 5 95.8 V7 6 96.1

The results reported in Table 3 clearly show that the exemplary (B) unsupported catalyst moldings having the stoichiometry of their multimetal oxide according to the invention have the better catalyst performance both in terms of activity (higher propene loads are associated with sales target) and overall target product selectivity compared to the comparative ( V) have Vollkatalysatorformkörpern.

The propene load PL, which is still compatible at a bath temperature of 320 ° C. with a propene conversion target of 95 mol%, reflects the activity of the catalyst used. The higher "PL", the higher the activity. In addition, the results reported in Table 3 indicate that an increased relative water content when aqueous solution A is mixed with aqueous solution B is conducive to both the resulting activity and the resulting overall target product selectivity (B1 is better than B2; B3 is better than B4 V4 is better than V5, the multimetal oxides of the comparative pairs always have a uniform stoichiometry).

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 19855913 A [0003, 0004, 0005, 0006]
• DE 10063162 A [0006, 0053, 0055, 0061]
• DE 102005037678 A [0006]
• DE 10059713 A [0006]
• DE 10049873 A [0006, 0052, 0056, 0061]
• DE 102007003076 A [0006, 0030]
• DE 102008054586 A [0006]
• DE 102007005606 A [0006, 0064, 0065]
• DE 102007004961 A [0006, 0064, 0077, 0119]
• DE 102006044520 A [0044]
• DE 2909671 A [0055]
• EP 293859A [0055]
• EP 714700A [0055]
• DE 4442346 A [0055]
• WO 2008/087116 [0063, 0064, 0065, 0119, 0169]
• DE 102008042060 A [0063, 0119]
• WO 2005/030393 [0064, 0065, 0070, 0076, 0077, 0119]
• US 2005/0131253 A [0064, 0065]
• WO 2007/017431 [0064, 0070, 0077, 0119]
• DE 102008040093 A [0064, 0070, 0076, 0077, 0077, 0119, 0160]
• DE 102008040094 A [0070, 0076, 0119, 0160]
• WO 02/062737 [0074]
• EP 184790A [0077]
• DE 10046957 A [0106]
• WO 02/24620 [0106, 0119]
• US 2005/0131253 [0107]
• WO 2006/42459 [0116]
• WO 02/49757 [0119]
• EP 575897A [0119]
• WO 2007/082827 [0119]
• WO 2005/113127 [0119]
• WO 2005/047224 [0119]
• WO 2005/042459 [0119]
• DE 102010048405 A [0119]
• DE 102009047291 A [0119, 0157]
• DE 102008042064 A [0119]
• DE 102008042061 A [0119]
• EP 990636 A [0137, 0137]
• EP 1106598 A [0137, 0137, 0137, 0148, 0149]
• DE 10246119A [0138]
• DE 10245585. A [0138]
• DE 4407020 A [0140]
• DE 10232748A [0144]
• DE 4431957 A [0146]
• EP 700714 A [0146, 0149]
• EP 700893 A [0146]
• EP 468290 B [0147]
• DE 19910506 A [0148]
• DE 10313213 A [0148, 0149]
• DE 10313208 A [0148, 0149]
• DE 19948523 A [0149]
• DE 19948248 A [0149]
• DE 10313209 A [0149]
• WO 00/53557 [0149, 0149]
• WO 00/53558 [0149]
• WO 01/36364 [0149]
• EP 873783 A [0149]
• DE 10337788 A [0157]
• DE 79219 [0164]
• DE 10200804093 A [0169]

Cited non-patent literature

• DIN 4768 sheet 1 with a "Hommel tester for DIN-ISO surface measurement sizes" from Hommelwerke, DE [0058]
• "The Tablet", Handbook of Development, Production and Quality Assurance, WARitschel and A.Bauer-Brandl, 2nd edition, Edition Verlag Aulendorf, 2002 [0069]
• ISO 13320 [0086]
• DIN 66131 [0089]
• P. Kubelka, F.Munk, Z.Tech.Phys. 1931, 12, p. 593 ff. [0175]

Claims (13)

Mo, Bi and Fe-containing multimetal oxide of the general stoichiometry I, Mo ₁₂ Bi _a Co _b Fe _c K _d Si _e O _x (I), in which the variables have the following meaning: a = 0.5 to 1, b = 7 to 8.5, c = 1.5 to 3.0, d = 0 to 0.15, e = 0 to 2.5, and x = a number determined by the valency and frequency of the elements other than oxygen in I. , and satisfy the following conditions: condition 1: 12-b-1.5 · c = A, and 0.5≤A≤1.5; Condition 2: 0.2 ≤ a / A ≤ 1.3; and condition 3: 2.5 ≦ b / c ≦ 9. Multimetal oxide composition according to claim 1, whose stoichiometric coefficient d is 0.04 to 0.1. Multimetal oxide composition according to claim 1 or 2, whose stoichiometric coefficient e is 0.5 to 2. The multimetal oxide composition according to any one of claims 1 to 3 satisfying the condition 1, 0.5 ≦ A ≦ 1.25. The multimetal oxide composition according to any one of claims 1 to 4 satisfying condition 2, 0.3 ≤ a / A ≤ 1.2. The multimetal oxide composition according to any one of claims 1 to 5 satisfying the condition 3, 3 ≦ b / c ≦ 9. A coated catalyst comprising a carrier shaped body and a shell of at least one multimetal oxide composition according to one of claims 1 to 6 located on the outer surface of the carrier shaped body. Unsupported catalyst body whose active composition is at least one multimetal oxide according to one of claims 1 to 6. The unsupported catalyst body according to claim 8, which has the geometry of a ring having a wall thickness of 1 to 3 mm, a length of 2 to 10 mm and an outer diameter of 2 to 10 mm. Process for the preparation of a multimetal oxide composition according to one of Claims 1 to 6, characterized in that a finely divided dry mixture is produced from sources of its elemental constituents and this is calcined at temperatures in the range from 350 to 650 ° C. A process of heterogeneously catalyzed gas phase oxidation of a 3 to 6 C atoms alkane, alkanol, alkanal, alkenes and / or alkenals on a catalyst bed, characterized in that the catalyst bed at least one Multimetalloxidmasse according to any one of claims 1 to 6, or at least one catalyst according to one of claims 7 to 9, or at least one product of a method according to claim 10. A method according to claim 11, characterized in that it is a method of heterogeneously catalyzed partial gas phase oxidation of propene to acrolein. Use of at least one multimetal oxide according to one of claims 1 to 6, or at least one catalyst according to one of claims 7 to 9, or at least one product of a process according to claim 10 for catalysing a process of heterogeneously catalyzed partial gas phase oxidation of a 3 to 6 carbon atoms Alkanes, alkanols, alkanals, alkenes and / or alkenals on a catalyst bed.

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