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WO1997047387A1 - Process for producing a catalyst consisting of a substrate and a catalytically active compound applied to the upper surface of said substrate - Google Patents

Process for producing a catalyst consisting of a substrate and a catalytically active compound applied to the upper surface of said substrate Download PDF

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Publication number
WO1997047387A1
WO1997047387A1 PCT/EP1997/002819 EP9702819W WO9747387A1 WO 1997047387 A1 WO1997047387 A1 WO 1997047387A1 EP 9702819 W EP9702819 W EP 9702819W WO 9747387 A1 WO9747387 A1 WO 9747387A1
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WO
WIPO (PCT)
Prior art keywords
movement
catalytically active
carrier
amount
mass
Prior art date
Application number
PCT/EP1997/002819
Other languages
German (de)
French (fr)
Inventor
Hartmut Hibst
Original Assignee
Basf Aktiengesellschaft
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Basf Aktiengesellschaft filed Critical Basf Aktiengesellschaft
Priority to AU31699/97A priority Critical patent/AU3169997A/en
Publication of WO1997047387A1 publication Critical patent/WO1997047387A1/en

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/02—Impregnation, coating or precipitation
    • B01J37/0215—Coating
    • B01J37/0221—Coating of particles
    • B01J37/0223—Coating of particles by rotation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/002—Mixed oxides other than spinels, e.g. perovskite
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/02—Impregnation, coating or precipitation
    • B01J37/0215—Coating
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2523/00—Constitutive chemical elements of heterogeneous catalysts

Definitions

  • the present invention relates to a process for producing a catalyst which consists of a support body and a catalytically active composition applied to the surface of the support body.
  • the present invention further relates to catalysts which consist of a support body and a catalytically active composition applied to the surface of the support body and are referred to as shell catalysts, and to the use of such shell catalysts.
  • DE-A 2 351 151 relates to catalytic oxidation, ammoxidation and the oxidative dehydrogenation of olefins containing 3 to 5 carbon atoms on catalytically active oxide materials in the gas phase.
  • Exemplary embodiments form the conversion of butadiene to maleic anhydride, from propene to acrolein, from acrolein to
  • Acrylic acid from propene to acrylonitrile and from 2-butene to butadiene.
  • DE-A 16 42 921 and DE-A 21 06 796 teach the catalytic gas phase oxidation of aromatic and unsaturated hydrocarbons, naphthalene, o-xylene, benzene or n-butene to carboxylic acids or their anhydrides. Exemplary embodiments form the conversion of o-xylene to phthalic anhydride and of butadiene to maleic anhydride. From DE-A 25 26 238 it is known to produce acrylic acid or methacrylic acid by catalytic gas phase oxidation of acrolein or methacrolein on catalytically active oxide materials.
  • DE-A 20 25 430 relates to the catalytic gas phase oxidation of indanes to, for example, anthraquinone.
  • the catalytically active oxide mass can only contain another element or more than another element (multi-element oxide masses).
  • Catalytically active oxide compositions which comprise more than one metallic, in particular transition, metallic element are used particularly frequently.
  • metallic, in particular transition, metallic element are used particularly frequently.
  • Multielement oxide materials are usually not simple physical mixtures of oxides of the elemental constituents, but rather heterogeneous mixtures of complex poly compounds of these elements.
  • shaped bodies are usually formed from the catalytically active oxide mass, the longitudinal dimension of which, as a function of the inside diameter of the contact tube, is generally a few millimeters.
  • a disadvantage of shaped bodies which consist exclusively of the catalytically active oxide composition is that on the one hand they have to have a certain thickness in order to meet the requirement for satisfactory mechanical stability.
  • a disadvantage of larger active material thicknesses, however, is that they involve an extension of the diffusion path out of the reaction zone, which promotes undesired subsequent reactions and thus reduces the target product selectivity.
  • the mechanical stability is ensured by the carrier and the oxidic active material can be applied in the desired layer thickness on the carrier surface.
  • the carrier bodies are preferably hollow or fully cylindrical or spherical.
  • the oxidic active composition can be applied as such or in the form of a catalyst precursor composition which, after application, is then converted into the actual oxidic active composition by thermal treatment (calcination).
  • shell catalysts based on catalytically active oxide materials can be produced by applying the catalytically active material to the carrier body with the aid of the plasma spraying or flame spraying process.
  • a disadvantage of the applicability of this process is that the meltability of at least one main component must be given at the working temperature of the flame spray or plasma torch.
  • Another disadvantage of this method is that the size of the specific catalytically active surface is generally unsatisfactory.
  • DE-A 20 25 430 contains a process for the preparation of a spherical coated catalyst in which an aqueous solution containing oxalic acid and the catalytically active oxide composition is sprayed onto hot carrier balls.
  • a disadvantage of this procedure is that it can only be used with water-soluble catalytically active oxide compositions.
  • DE-A 16 42 921 relates to the production of spherical oxidic coated catalysts by spraying a liquid containing the oxidic active composition in dissolved or suspended form onto hot spherical support bodies.
  • DE-A 16 42 921 recommends water or an organic solvent such as alcohol or formamide as the solvent or suspending medium.
  • a disadvantage here is also that the water or solvent evaporates practically in one fell swoop as soon as the sprayed-on mass comes into contact with the hot carrier, which reduces the adhesive strength of the shell.
  • DE-A 25 10 994 corresponds essentially to the teaching of DE-A 16 42 921 with the difference that it also includes ring-shaped carriers.
  • DE-A 21 06 796 discloses the preparation of coated catalysts by spraying aqueous suspensions of the catalytically active oxidic material onto the moving support bodies. This procedure has the same disadvantages as for the spraying of the oxidic Described active composition dissolved aqueous solutions. This applies in particular to spraying onto heated carrier bodies. The recommendation that an aqueous polymer dispersion be used as a binder cannot remedy this disadvantage, but rather the presence of one makes it difficult
  • DE-A 26 26 887 attempts to alleviate the disadvantages of DE-A 21 06 796 by spraying the aqueous suspension onto carrier balls having a temperature of only 25 to 80 ° C. According to DE-A 29 09 671, page 5, line 10, this procedure can lead to sticking of the sprayed carrier bodies. To increase the adhesive strength of the oxidic catalytically active shell on the surface of the
  • Carrier body recommends DE-A 26 26 887 to incorporate inorganic hydroxy salts into the aqueous suspension to be sprayed on, which hydrolyze to hydroxides in aqueous solution and, after the shell catalyst has been produced, form catalytically indifferent constituents of the catalytically active oxide composition.
  • a disadvantage of this measure is that it requires a dilution of the oxidic active composition.
  • DE-A 29 09 670 corresponds essentially to that of DE-A 26 26 887. According to the description of DE-A 29 09 670, mixtures of water and alcohol can also be used as the suspension medium. After the suspension of the catalytically active oxide composition has been sprayed on, the moisture content is removed by passing hot air over it.
  • GB-1 331 423 relates to a process for the preparation of spherical oxide coated catalysts which is characterized in that an aqueous suspension or solution is formed from catalyst precursors and an organic auxiliary substance which is soluble in water , mixed with the carrier bodies and, with occasional stirring, the liquid constituents removed by evaporation.
  • the coated support bodies obtained in this way are then calcined and the catalyst precursor layer is converted into active oxide.
  • a disadvantage here is the need to have to evaporate the liquid components after the coating is finished and the possible reactive interaction of the organic auxiliary substance with the catalyst precursor.
  • EP-A 284 448 and EP-A 37 492 recommend the production of coated catalysts by the spray process already described, or by the process of GB-1 331 423, with the disadvantages already mentioned.
  • EP-B 293 859 discloses a method for producing spherical coated catalysts by using a centrifugal flow coating device. The coating takes place by means of a catalyst precursor mass.
  • EP-B 293 859 recommends e.g. Water, alcohol and acetone.
  • EP-B 293 859 A disadvantage of the teaching of EP-B 293 859 is again the need to use a binder.
  • DE-A 25 26 238 and US Pat. No. 3,956,377 disclose a process for producing spherical oxide coated catalysts in which the carrier balls are first moistened with water or other liquids such as petroleum ether as binders. Subsequently, the catalytically active oxide mass is applied to the carrier material moistened with binder by rolling the moist carrier material in the powdery catalytically active oxide mass.
  • a disadvantage of this procedure is again the requirement that the binder be used and that the achievable shell thickness is limited by the binder absorption capacity of the carrier, since this amount of binder absorbed by the carrier is responsible for binding the entire powdery oxide mass to be absorbed.
  • Another disadvantage of the method is that the degree of moistening of the respective surface layer varies continuously during the coating process.
  • the base layer meets the moisture of the uncoated substrate. Subsequently, the moisture first has to migrate through the base layer to its surface in order to be able to adhere further active composition, etc. As a result, an onion-like shell structure is obtained, the adherence of successive layers in particular not being satisfactory.
  • DE-A 29 09 671 tries to alleviate the disadvantages of the procedure described above by filling the spherical carrier bodies into an inclined rotating turntable.
  • the rotating turntable guides the spherical carrier bodies periodically under two metering devices arranged one after the other at a certain distance.
  • the first of the two metering devices corresponds to a nozzle through which the Carrier balls are sprayed with water and moistened in a controlled manner.
  • the second metering device is located outside the atomizing cone of the sprayed-in water and is used to supply finely divided oxidic active material.
  • the controlled moistened carrier balls take up the supplied catalyst powder, which is compacted into a coherent shell by the rolling movement on the outer surface of the carrier balls.
  • the carrier ball coated in this way as it were a new carrier body, again passes through the spray nozzle in the course of the subsequent rotation, is moistened in a controlled manner in the same way in order to be able to take up a further layer of finely divided oxidic active material in the course of the further movement etc.
  • a disadvantage of this procedure is that the water used as a binder must finally be removed by introducing hot air.
  • the teaching of DE-A 44 32 795 is a further development of the teaching of DE-A 29 09 671 and differs from the latter in that an aqueous solution of an organic substance boiling at normal pressure above 100 ° C. is used as the liquid binder .
  • the object of the present invention was therefore to provide a process for producing a catalyst consisting of a support body and a catalytically active composition applied to the surface of the support body, which on the one hand does not require the use of a liquid binder and on the other hand does not have the disadvantages of the plasma spraying or flame spraying process of DE-A 20 25 430.
  • a process for the preparation of a catalyst consisting of a support body and a catalytically active composition applied to the surface of the support body which is characterized in that the catalytically active composition or a precursor composition thereof, together with the support bodies, is placed in a cylindrical container there and moves it so that its total movement is a suspension of a rotary movement of the cylindrical container about its own (central) longitudinal axis (movement 1) and a circular movement of this longitudinal axis (movement 2), with the proviso that the direction of the vector of the angular velocity of the movement 1 [ ⁇ lj is opposite to the direction of the vector of the angular velocity of the movement 2 ⁇ ⁇ 2 j, 5 - the amount of the smaller of the two angular speeds is at least 50%, preferably at least 75%, the amount of the larger of the two angular velocities,
  • the amount of the smaller of the two angular speeds is preferably at least 90, advantageously at least 95% of the amount of the larger of the two angular speeds.
  • the amounts of the two angular velocities ⁇ 1 , ⁇ 2 are of particular advantage with the same magnitude. Furthermore, it is favorable if the
  • centrifugal acceleration of movement 2 is at least three times or five times, advantageously at least ten times the acceleration due to gravity.
  • the centrifugal acceleration of movement 2 will be at least twenty or at least thirty times the acceleration due to gravity.
  • the inner diameter of the cylindrical container is usually 10 to 50, usually 20 to
  • the inner diameter of the cylindrical container is a multiple of the longest dimension (in the case of a ball, its diameter) of the carrier body (typically 10 to 100 times).
  • the form of movement according to the invention of the carrier body and the catalytically active composition to be applied to it is guaranteed between the two
  • the base-coated carrier body acts as a new carrier body, etc.
  • the targeted choice of the ratio of the total surface to be coated and the amount of material to be applied to the same can be adjusted essentially as required.
  • the uniformly coated carrier bodies can be removed from the same.
  • the form of movement of the cylindrical container according to the invention can be realized in a simple manner by attaching the cylindrical container to a horizontally rotating sun disk and rotating it in the opposite direction to its rotating longitudinal disk about its own longitudinal axis.
  • Such an arrangement is e.g. commercially available in the form of high-speed planetary mills (see SPRECHSAAL, Vol. 125, No. 7, 1992, p. 397 ff; cav 1993, June, p. 98 ff; planetary high-speed mill, company publication of
  • the sun disk of such a high-speed planetary mill carries four cylindrical cups in an arrangement according to FIGS. 1 and 2 (taken from SPRECHSAAL, Vol. 125, No. 7, 1992, p. 398 and p. 399).
  • FIGS. 1 and 2 have the following meaning:
  • ri radius of movement of the spherical support body in point A through the rotation of the sun disk
  • r 2 radius of movement of the spherical support body in point B through the rotation of the sun disk
  • the centrifugal forces act alternately in the same and opposite directions. This results in successive running of the support bodies on the inner wall of the cup and lifting and free passage through the coating material and support bodies through the interior of the cup.
  • the cylinder cup is normally closed by a cover.
  • the materials of the support bodies are preferably chemically inert, ie they essentially do not intervene in the course of the chemical reaction, for example gas phase oxidation, which is catalyzed by the coated catalysts produced according to the invention.
  • aluminum oxide, silicon dioxide, silicates such as clay, kaolin, steatite, pumice, aluminum silicate and magnesium silicate, silicon carbide, zirconium dioxide and thorium dioxide are particularly suitable as materials for the carrier bodies.
  • the surface of the carrier body is advantageously rough, since an increased surface roughness generally causes an increased adhesive strength of the applied shell to oxidic active material.
  • the surface roughness R z of the carrier body is preferably in the range from 40 to 500 ⁇ m, preferably 40 to 200 ⁇ m (determined in accordance with DIN 4768 Sheet 1 using a “Hommel Tester for DIN-ISO surface measurement parameters” from Hommelwerke).
  • the carrier materials can be porous or non-porous.
  • the carrier material is often non-porous (total volume of the pores based on the volume of the carrier body ⁇ 1% by volume).
  • any geometries of the carrier bodies can be considered for the method according to the invention.
  • Their longest dimension is usually 1 to 10 mm.
  • balls or cylinders, in particular hollow cylinders, are preferably used as carrier bodies.
  • cylinders are used as carrier bodies, their length is preferably 2 to 10 mm and their outside diameter is preferably 4 to 10 mm.
  • the wall thickness is usually 1 to 4 mm.
  • Particularly preferred ring-shaped carrier bodies have a length of 3 to 6 mm, an outer diameter of 4 to 8 mm and a wall thickness of 1 to 2 mm. Rings of geometry 7 mm x 3 mm x 4 mm (outer diameter x length x inner diameter) are very particularly preferred.
  • the thickness of the catalytically active composition is expediently as a rule from 5 nm to 1000 ⁇ m. 10 nm to 500 ⁇ m, particularly preferably 100 nm to 500 ⁇ m and very particularly preferably 200 nm to 300 ⁇ m, are preferred, in particular in the case of ring-shaped carrier bodies.
  • the fineness of the catalytically active mass to be applied to the surface of the carrier body, such as the catalytically active oxide mass is of course applied to the desired shell. adjusted thickness.
  • the method according to the invention can be repeated periodically to achieve an increased shell thickness.
  • Binder does not need, which excludes a reaction with the mostly organic binder.
  • the material used for coating does not necessarily have to be used in finely divided form. Rather, it can be assumed that the starting material is of a coarse particle size, that if the carrier body is selected appropriately, the process according to the invention is subject to a milling process until the Van der Waals forces that are developed enable the force to be drawn up onto the surface of the carrier body. An otherwise required separate grinding process can be omitted.
  • a further essential feature of the method according to the invention is that both the catalytically active oxidic mass as such and also a preliminary discharge of the same can be applied to the carrier body.
  • catalytically active oxidic masses For the production of catalytically active oxidic masses, it is customary to start from sources of the catalytically active, oxidic masses which are suitable in a manner known per se and to produce an intimate, preferably finely divided,
  • Dry mixture (which can be applied as a precursor mass to the surface of the carrier body), which is then subjected to the calcination (thermal treatment) and, if appropriate, converted into finely divided form by grinding. If the pre-discharge is already applied, the application is calculated after the application has been completed. This usually leads to coated catalysts with an increased specific surface area of the active composition.
  • the sources are either already oxides or such
  • the intimate mixing of the starting compounds can take place in dry or in wet form. If it is carried out in dry form, the starting compounds are expediently used as finely divided powders and, after mixing and optionally pressing, are subjected to the calcination. However, the intimate mixing is preferably carried out in wet form.
  • the starting compounds are usually in the form of an aqueous solution or S uspension mixed together.
  • the aqueous mass is then dried and, after drying, calcined.
  • the drying process is preferably carried out by spray drying.
  • the case anfal ⁇ loin powder turns out for immediate further processing often be too finely divided. In these cases, it can be kneaded with the addition of water.
  • the modeling clay obtained is then subjected to the calcination and then ground to a finely divided oxidic active composition.
  • the process according to the invention is favorable in the case of multimetal oxide compositions containing Mo and V or Mo, Fe and Bi.
  • X 4 at least one or more alkali metals
  • X 5 at least one or more alkaline earth metals, X 6 Si, Al, Ti and / or Zr, a 1 to 6, b 0.2 to 4, c 0.5 to 18, d 0 to 40, e 0 to 2, f 0 to 4, g 0 to 40 and n a number which is determined by the valency and frequency of the elements other than oxygen in I.
  • DE-A 43 35 973 describes the preparation of active multimetal oxides I, including the calcination conditions.
  • DE-A 43 35 973 also discloses preferred embodiments within active multimetal oxides I. These include, for example, those multimetal oxides I that are described below Meanings of the variables of the general formula I are recorded: ⁇ i W, Nb and / or Cr,
  • n is a number which is determined by the valency and frequency of the elements in I other than oxygen.
  • multimetal oxides I are those of the general formula I '
  • X 6 Si and / or AI a 3 to 4.5, b 1 to 1.5, c 0.75 to 2.5, f 0 to 0.5, g 0 to 8 and n a number represented by the Value and frequency of elements other than oxygen is determined in I '.
  • Shell catalysts produced according to the invention with the active multimetal oxides I are particularly suitable for the gas-phase catalytically oxidative production of acrylic acid from acrolein. This applies in particular to spherical or ring-shaped shell catalysts. Especially if they have the characteristics (geometry, shell thickness, etc.) described as preferred in this document.
  • the general reaction conditions for the gas phase catalytic oxidation of acrolein to acrylic acid can also be found in DE-A 43 35 973.
  • the process according to the invention is also suitable in the case of active multimetal oxides as are used for the catalytic gas phase oxidation of methacrolein to methacrylic acid and are described, for example, in DE-A 40 22 212.
  • the method according to the invention proves itself in the case of active multimetal oxides of general stoichiometry II to be applied as a shell
  • Tungsten X 4 silicon, aluminum, titanium and / or zirconium, a 0.5 to 5, b 0, 01 to 3, c 3 to 10, d 0.02 to 2, e 0 to 5, f 0 to 10 and n a number, which is determined by the valency and frequency of the elements other than oxygen in II, as suitable.
  • DE-A 40 23 239 describes the production of active multimetal oxides II, including the calcination conditions.
  • Shell catalysts produced according to the invention with the active multimetal oxides II are particularly suitable for the gas-phase catalytic oxidative production of acrolein from propene. This applies in particular to spherical or ring-shaped coated catalysts. Especially if they have the characteristic (geometry, shell thickness, etc.) described as preferred in this document.
  • the general reaction conditions for the gas-phase catalytic oxidation of propene to acrolein can also be found in DE-A 40 23 239 and in DE-A 44 31 957.
  • the aforementioned shell catalysts of the active multimetal oxides II are also suitable for the gas-phase catalytically oxidative production of methacrolein from tert. -Butanol, isobutane, isobutene or tert. -Butyl methyl ether.
  • the general Reaction conditions for this catalytic gas phase oxidation can be found, for example, in DE-A 40 23 239 and in DE-A 43 35 172.
  • the method according to the invention is suitable in the case of the active oxide compositions of DE-A 44 05 514.
  • the process according to the invention is very generally suitable for producing coated catalysts based on active compositions, in particular for the catalyzed reactions listed in this document in the context of the assessment of the prior art.
  • the active composition is an oxidic active composition which only comprises another element in addition to oxygen.
  • the method according to the invention is suitable for the production of shell catalyst test quantities for shell catalyst screening.
  • FIGS. 1, 2 An arrangement according to FIGS. 1, 2 was used to apply the method according to the invention
  • Either smooth steatite spheres with a diameter of 1 mm or surface-rough stateite spheres (surface roughness R z 0.5 mm due to splitting) with a diameter of 2 mm were used as carrier bodies.
  • Carrier body duration of movement and revolutions per minute of the sun disk. All information relates to one (1) cylinder cup.
  • the amount of the oxide layer applied is given in% by weight, based on the weight of the carrier ball.

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  • Engineering & Computer Science (AREA)
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Abstract

A process for producing a cup catalyst in which the active compound or a precursor compound thereof is placed together with the substrates in a cylindrical jar which is moved in such a way that its overall movement consists of a superimposition of a rotary movement of the cylindrical jar and a circular movement of its longitudinal axis.

Description

Verfahren zur Herstellung eines Katalysators, bestehend aus einem Trägerkörper und einer auf der Oberfläche des Trägerkörpers auf¬ gebrachten katalytisch aktiven MasseProcess for producing a catalyst consisting of a support body and a catalytically active composition applied to the surface of the support body
Beschreibungdescription
Vorliegende Erfindung betrifft ein Verfahren zur Herstellung eines Katalysators, der aus einem Trägerkörper und einer auf der Oberfläche des Trägerkörpers aufgebrachten katalytisch aktiven Masse besteht.The present invention relates to a process for producing a catalyst which consists of a support body and a catalytically active composition applied to the surface of the support body.
Ferner betrifft vorliegende Erfindung Katalysatoren, die aus einem Trägerkörper und einer auf der Oberfläche des Trägerkörpers aufgebrachten katalytisch aktiven Masse bestehen und als Schalen- katalysatoren bezeichnet werden, sowie die Verwendung solcher Schalenkatalysatoren.The present invention further relates to catalysts which consist of a support body and a catalytically active composition applied to the surface of the support body and are referred to as shell catalysts, and to the use of such shell catalysts.
Es ist allgemein bekannt, daß chemische Umsetzungen häufig in vorteilhafter Weise an katalytisch aktiven Feststoffen durchge¬ führt werden können. Beispiele hierfür sind die Hydrierung ethylenisch ungesättigter Doppelbindungen mit Raney-Nickel, die Epoxidierung von Ethylen an Silber, die Dehydratisierung von Ethanol an γ-Al203, die Entschwefelung von Mineralöl an MoS2, die Polymerisation von ethylenisch ungesättigten Monomeren an Metal- locenen, etc. (vgl. Ullmann's Encyclopedia of Industrial Chemistry, Fifth Edition, Vol. A5, VCH Weinheim (1986), S. 313 bis 367) . Insbesondere ist bekannt, daß oxidative chemische Umsetzungen häufig in vorteilhafter Weise in der Gasphase an ka- talytisch aktiven Oxiden durchgeführt werden können. So betrifft die DE-A 2 351 151 die katalytische Oxidation, Ammoxidation sowie die oxidative Dehydrierung von 3 bis 5 C-Atome aufweisenden Olefinen an katalytisch aktiven Oxidmassen in der Gasphase. Bei¬ spielhafte Ausführungsformen bilden die Umsetzung von Butadien zu Maleinsäureanhydrid, von Propen zu Acrolein, von Acrolein zuIt is generally known that chemical reactions can often be carried out advantageously on catalytically active solids. Examples of this are the hydrogenation of ethylenically unsaturated double bonds with Raney nickel, the epoxidation of ethylene on silver, the dehydration of ethanol on γ-Al 2 0 3 , the desulfurization of mineral oil on MoS 2 , the polymerization of ethylenically unsaturated monomers on metal locenes , etc. (see Ullmann's Encyclopedia of Industrial Chemistry, Fifth Edition, Vol. A5, VCH Weinheim (1986), pp. 313 to 367). In particular, it is known that oxidative chemical reactions can often be carried out advantageously in the gas phase on catalytically active oxides. DE-A 2 351 151 relates to catalytic oxidation, ammoxidation and the oxidative dehydrogenation of olefins containing 3 to 5 carbon atoms on catalytically active oxide materials in the gas phase. Exemplary embodiments form the conversion of butadiene to maleic anhydride, from propene to acrolein, from acrolein to
Acrylsäure, von Propen zu Acrylnitril sowie von 2-Buten zu Buta¬ dien. Die DE-A 16 42 921 und die DE-A 21 06 796 lehren die kata¬ lytische Gasphasenoxidation von aromatischen und ungesättigten Kohlenwasserstoffen, Naphthalin, o-Xylol, Benzol oder n-Buten zu Carbonsäuren oder deren Anhydriden. Beispielhafte Ausführungsfor¬ men bilden die Umsetzung von o-Xylol zu Phthalsäureanhydrid sowie von Butadien zu Maleinsäureanhydrid. Aus der DE-A 25 26 238 ist bekannt, Acrylsäure oder Methacrylsäure durch katalytische Gas¬ phasenoxidation von Acrolein oder Methacrolein an katalytisch ak- tiven Oxidmassen zu erzeugen. Die DE-A 20 25 430 betrifft die ka¬ talytische Gasphasenoxidation von Indanen zu z.B. Anthrachinon. Die katalytisch aktive Oxidmasse kann neben Sauerstoff lediglich ein anderes Element oder mehr als ein anderes Element (Multi- elementoxidmassen) enthalten.Acrylic acid, from propene to acrylonitrile and from 2-butene to butadiene. DE-A 16 42 921 and DE-A 21 06 796 teach the catalytic gas phase oxidation of aromatic and unsaturated hydrocarbons, naphthalene, o-xylene, benzene or n-butene to carboxylic acids or their anhydrides. Exemplary embodiments form the conversion of o-xylene to phthalic anhydride and of butadiene to maleic anhydride. From DE-A 25 26 238 it is known to produce acrylic acid or methacrylic acid by catalytic gas phase oxidation of acrolein or methacrolein on catalytically active oxide materials. DE-A 20 25 430 relates to the catalytic gas phase oxidation of indanes to, for example, anthraquinone. In addition to oxygen, the catalytically active oxide mass can only contain another element or more than another element (multi-element oxide masses).
Besonders häufig kommen katalytisch aktive Oxidmassen zur Anwen- düng, die mehr als ein metallisches, insbesondere Übergangs- metallisches Element umfassen. In diesem Fall spricht man von Multimetalloxidmassen. Üblicherweise sind Multielementoxidmassen keine einfachen physikalischen Gemische von Oxiden der elementa¬ ren Konstituenten, sondern heterogene Gemisch von komplexen Poly- Verbindungen dieser Elemente.Catalytically active oxide compositions which comprise more than one metallic, in particular transition, metallic element are used particularly frequently. In this case one speaks of multimetal oxide masses. Multielement oxide materials are usually not simple physical mixtures of oxides of the elemental constituents, but rather heterogeneous mixtures of complex poly compounds of these elements.
In der Regel erfolgt die großtechnische Realisierung solcher ka- talytischer Gasphasenoxidationen in Festbettreaktoren. D.h., das Reaktionsgasgemisch durchströmt eine ruhende Katalysatorschüttung und die oxidative chemische Umsetzung erfolgt während der Ver¬ weilzeit in der selbigen.As a rule, such catalytic gas phase oxidations are implemented on a large scale in fixed bed reactors. In other words, the reaction gas mixture flows through a stationary bed of catalyst and the oxidative chemical conversion takes place in the same during the dwell time.
Die meisten katalytischen Gasphasenoxidationen verlaufen stark exotherm, weshalb man sie anwendungstechnisch zweckmäßig in Viel- kontaktrohr-Festbettreaktoren durchführt. Die Kontaktrohrlänge erstreckt sich im Normalfall auf wenige Meter und der Kontakt- rohrinnendurchmesser beläuft sich regelmäßig auf wenige Zentime¬ ter. Die Kontaktrohre umströmende Wärmeaustauschmittel führen die Prozeßwärme ab (vgl. z.B. die DE-A 44 31 957 und die DE-A 44 31 949) .Most catalytic gas phase oxidations are highly exothermic, which is why they are best used in many-contact tube fixed-bed reactors. The length of the contact tube normally extends to a few meters and the inside diameter of the contact tube is regularly a few centimeters. Heat exchange medium flowing around the contact tubes dissipate the process heat (cf. e.g. DE-A 44 31 957 and DE-A 44 31 949).
Festbettschüttungen aus feinteiliger, pulverförmiger, katalytisch aktiver Oxidmasse sind zur Durchführung katalytischer Gasphasen¬ oxidationen wenig geeignet, da sie wirtschaftlichen Belastungen mit Ausgangsreaktionsgasgemisch normalerweise nicht ohne hydrau¬ lische Förderung standzuhalten vermögen.Fixed bed fillings of finely divided, powdery, catalytically active oxide mass are not very suitable for carrying out catalytic gas phase oxidations since they normally cannot withstand economic loads with the starting reaction gas mixture without hydraulic promotion.
D.h., üblicherweise werden aus der katalytisch aktiven Oxidmasse Formkörper gebildet, deren Längstausdehnung, dem Kontaktrohr- innendurchmesser angemessen, in der Regel einige Millimeter be¬ trägt. Nachteilig an Formkörpern, die ausschließlich aus der ka¬ talytisch aktiven Oxidmasse bestehen, ist, daß sie einerseits eine gewisse Dicke aufweisen müssen, um dem Erfordernis einer be¬ friedigenden mechanischen Stabilität zu genügen. Nachteilig an größeren Aktivmassendicken ist jedoch, daß mit ihnen eine Verlän¬ gerung des Diffusionsweges aus der Reaktionszone heraus ein- hergeht, was unerwünschte Folgereaktionen fördert und damit die Zielproduktselektivität mindert.This means that shaped bodies are usually formed from the catalytically active oxide mass, the longitudinal dimension of which, as a function of the inside diameter of the contact tube, is generally a few millimeters. A disadvantage of shaped bodies which consist exclusively of the catalytically active oxide composition is that on the one hand they have to have a certain thickness in order to meet the requirement for satisfactory mechanical stability. A disadvantage of larger active material thicknesses, however, is that they involve an extension of the diffusion path out of the reaction zone, which promotes undesired subsequent reactions and thus reduces the target product selectivity.
Eine Auflösung dieses Widerspruchs zwischen erforderlicher mecha¬ nischer Stabilität einerseits und Begrenzung des Diffusionsweges aus der Reaktionszone heraus andererseits, eröffnen die an sich bekannten Schalenkatalysatoren. Die mechanische Stabilität wird durch den Träger gewährleistet und auf der Trägeroberfläche kann die oxidische Aktivmasse in der gewünschten Schichtdicke aufge¬ bracht sein. Bevorzugt sind die Trägerkörper hohl- oder vollzy- lindrisch oder kugelförmig. Das Aufbringen der oxidischen Aktiv- masse kann dabei als solche oder in Gestalt einer Katalysator¬ vorläufermasse erfolgen, die dann nach dem Aufbringen durch ther¬ mische Behandlung (Calcinierung) in die eigentliche oxidische Aktivmasse gewandelt wird.A resolution of this contradiction between the required mechanical stability on the one hand and the limitation of the diffusion path out of the reaction zone on the other hand opens this up known shell catalysts. The mechanical stability is ensured by the carrier and the oxidic active material can be applied in the desired layer thickness on the carrier surface. The carrier bodies are preferably hollow or fully cylindrical or spherical. The oxidic active composition can be applied as such or in the form of a catalyst precursor composition which, after application, is then converted into the actual oxidic active composition by thermal treatment (calcination).
Aus der DE-A 20 25 430 ist bekannt, daß man Schalenkatalysatoren auf der Basis katalytisch aktiver Oxidmassen dadurch herstellen kann, daß man das katalytisch aktive Material mit Hilfe des Plas¬ maspritz- oder Flammspritzverfahrens auf den Trägerkörper auf- bringt. Nachteilig hinsichtlich der Anwendbarkeit dieses Verfah¬ rens ist, daß die Schmelzbarkeit mindestens einer Hauptkomponente bei der Arbeitstemperatur des Flammspritz- oder des Plasmabren¬ ners gegeben sein muß. Ein weiterer Nachteil dieses Verfahrens besteht darin, daß die Größe der spezifischen katalytisch aktiven Oberfläche in der Regel nicht zu befriedigen vermag. AlsFrom DE-A 20 25 430 it is known that shell catalysts based on catalytically active oxide materials can be produced by applying the catalytically active material to the carrier body with the aid of the plasma spraying or flame spraying process. A disadvantage of the applicability of this process is that the meltability of at least one main component must be given at the working temperature of the flame spray or plasma torch. Another disadvantage of this method is that the size of the specific catalytically active surface is generally unsatisfactory. As
Vergleichsbeispiel enthält die DE-A 20 25 430 ein Verfahren zur Herstellung eines kugelförmigen Schalenkatalysators, bei dem eine Oxalsäure und die katalytisch aktive Oxidmasse gelöst enthaltende wäßrige Lösung auf heiße Trägerkugeln aufgesprüht wird. Nach- teilig an dieser Verfahrensweise ist, daß sie nur bei in Wasser löslichen katalytisch aktiven Oxidmassen angewendet werden kann. Außerdem führt sie zu unregelmäßiger Schalendicke sowie nicht be¬ friedigender Schalenhaftung infolge der schlagartigen Verdampfung des Lösungsmittels an der Oberfläche der heißen Trägerkugel. Die DE-A 16 42 921 betrifft die Herstellung kugelförmiger oxidischer Schalenkatalysatoren durch Aufsprühen einer die oxidische Aktiv¬ masse in gelöster oder suspendierter Form enthaltenden Flüssig¬ keit auf heiße kugelförmige Trägerkörper. Als Lösungsmittel bzw. Suspendiermedium empfiehlt die DE-A 16 42 921 Wasser oder ein or- ganisches Lösungsmittel wie Alkohol bzw. Formamid. Nachteilig ist auch hier u.a., daß das Wasser bzw. Lösungsmittel praktisch auf einen Schlag verdampft, sobald die aufgesprühte Masse mit dem heißen Träger in Berührung kommt, was die Haftfestigkeit der Schale mindert.Comparative example, DE-A 20 25 430 contains a process for the preparation of a spherical coated catalyst in which an aqueous solution containing oxalic acid and the catalytically active oxide composition is sprayed onto hot carrier balls. A disadvantage of this procedure is that it can only be used with water-soluble catalytically active oxide compositions. In addition, it leads to irregular shell thickness and unsatisfactory shell adhesion due to the sudden evaporation of the solvent on the surface of the hot carrier ball. DE-A 16 42 921 relates to the production of spherical oxidic coated catalysts by spraying a liquid containing the oxidic active composition in dissolved or suspended form onto hot spherical support bodies. DE-A 16 42 921 recommends water or an organic solvent such as alcohol or formamide as the solvent or suspending medium. A disadvantage here is also that the water or solvent evaporates practically in one fell swoop as soon as the sprayed-on mass comes into contact with the hot carrier, which reduces the adhesive strength of the shell.
Die Lehre der DE-A 25 10 994 entspricht im wesentlichen der Lehre der DE-A 16 42 921 mit dem Unterschied, daß sie auch ringförmige Träger einschließt. Aus der DE-A 21 06 796 ist die Herstellung von Schalenkatalysatoren bekannt, indem man wäßrige Suspensionen des katalytisch wirksamen oxidischen Materials auf die bewegten Trägerkörper sprüht. Diese Verfahrensweise weist dieselben Nach¬ teile auf, wie bereits für das Aufsprühen von die oxidische Aktivmasse gelöst enthaltenden, wäßrigen Lösungen beschrieben. Dies gilt insbesondere für das Aufsprühen auf erhitzte Träger- körper. Diesen Nachteil vermag auch die Empfehlung der Mit- verwendung einer wäßrigen Polymerisatdispersion als Bindemittel nicht abzuhelfen, vielmehr erschwert das Beisein einerThe teaching of DE-A 25 10 994 corresponds essentially to the teaching of DE-A 16 42 921 with the difference that it also includes ring-shaped carriers. DE-A 21 06 796 discloses the preparation of coated catalysts by spraying aqueous suspensions of the catalytically active oxidic material onto the moving support bodies. This procedure has the same disadvantages as for the spraying of the oxidic Described active composition dissolved aqueous solutions. This applies in particular to spraying onto heated carrier bodies. The recommendation that an aqueous polymer dispersion be used as a binder cannot remedy this disadvantage, but rather the presence of one makes it difficult
Polymerisatdispersion den Beschichtungsvorgang durch schwer kon¬ trollierbare Filmbildungsprozesse.Polymer dispersion the coating process by difficult to control film formation processes.
Die DE-A 26 26 887 versucht die Nachteile der DE-A 21 06 796 da- durch zu mindern, daß das Aufsprühen der wäßrigen Suspension auf lediglich eine Temperatur von 25 bis 80°C aufweisende Trägerkugeln erfolgt. Gemäß der DE-A 29 09 671, Seite 5, Zeile 10, kann es bei dieser Verfahrensweise jedoch zu Verklebungen der besprühten Trägerkörper kommen. Zur Erhöhung der Haftfestigkeit der oxidischen katalytisch aktiven Schale auf der Oberfläche desDE-A 26 26 887 attempts to alleviate the disadvantages of DE-A 21 06 796 by spraying the aqueous suspension onto carrier balls having a temperature of only 25 to 80 ° C. According to DE-A 29 09 671, page 5, line 10, this procedure can lead to sticking of the sprayed carrier bodies. To increase the adhesive strength of the oxidic catalytically active shell on the surface of the
Trägerkörpers empfiehlt die DE-A 26 26 887 das Einarbeiten anor¬ ganischer Hydroxysalze in die aufzusprühende wäßrige Suspensison, die in wäßriger Lösung zu Hydroxiden hydrolysieren und nach Fer¬ tigstellung des Schalenkatalysators katalytisch indifferente Be- standteile der katalytisch aktiven Oxidmasse bilden. Nachteilig an dieser Maßnahme ist jedoch, daß sie eine Verdünnung der oxidischen Aktivmasse bedingt.Carrier body recommends DE-A 26 26 887 to incorporate inorganic hydroxy salts into the aqueous suspension to be sprayed on, which hydrolyze to hydroxides in aqueous solution and, after the shell catalyst has been produced, form catalytically indifferent constituents of the catalytically active oxide composition. However, a disadvantage of this measure is that it requires a dilution of the oxidic active composition.
Die Lehre der DE-A 29 09 670 entspricht im wesentlichen derjeni- gen der DE-A 26 26 887. Gemäß Beschreibung der DE-A 29 09 670 können als Suspendiermedium auch Gemische aus Wasser und Alkohol verwendet werden. Nach Beendigung des Aufsprühens der Suspension der katalytisch aktiven Oxidmasse wird durch Überleiten von hei¬ ßer Luft der Feuchtigkeitsgehalt beseitigt. Nachteilig an der Verfahrensweise der DE-A 29 09 670 ist, wie bereits mit Bezug auf die DE-A 26 26 887 erwähnt, die Neigung der besprühten Formkörper zum Agglomerieren sowie die potentielle reduzierende Wirkung des Alkohols auf die Aktivmasse.The teaching of DE-A 29 09 670 corresponds essentially to that of DE-A 26 26 887. According to the description of DE-A 29 09 670, mixtures of water and alcohol can also be used as the suspension medium. After the suspension of the catalytically active oxide composition has been sprayed on, the moisture content is removed by passing hot air over it. A disadvantage of the procedure of DE-A 29 09 670, as already mentioned with reference to DE-A 26 26 887, is the tendency of the sprayed moldings to agglomerate and the potential reducing effect of the alcohol on the active composition.
Die GB-1 331 423 betrifft ein Verfahren zur Herstellung von ku¬ gelförmigen oxidischen Schalenkatalysatoren, das dadurch gekenn¬ zeichnet ist, daß man aus Katalysatorvorläufern und einer organi¬ schen Hilfssubstanz, die in Wasser löslich ist, eine wäßrige Sus¬ pension oder Lösung bildet, selbige mit den Trägerkörpern ver- setzt und unter gelegentlichem Umrühren die flüssigen Bestand¬ teile durch Verdampfen entfernt. Anschließend werden die so erhaltenen beschichteten Trägerkörper calciniert und die Katalysatorvorläuferschicht in aktives Oxid umgewandelt. Nach¬ teilig ist auch hier das Erfordernis, die flüssigen Bestandteile nach beendeter Beschichtung verdampfen zu müssen und die mögliche reaktive Wechselwirkung der organischen Hilfssubstanz mit dem Katalysatorvorläufer.GB-1 331 423 relates to a process for the preparation of spherical oxide coated catalysts which is characterized in that an aqueous suspension or solution is formed from catalyst precursors and an organic auxiliary substance which is soluble in water , mixed with the carrier bodies and, with occasional stirring, the liquid constituents removed by evaporation. The coated support bodies obtained in this way are then calcined and the catalyst precursor layer is converted into active oxide. A disadvantage here is the need to have to evaporate the liquid components after the coating is finished and the possible reactive interaction of the organic auxiliary substance with the catalyst precursor.
Die EP-A 284 448 und die EP-A 37 492 empfehlen die Herstellung von Schalenkatalysatoren nach dem bereits beschriebenen Sprüh¬ verfahren, bzw. nach dem Verfahren der GB-1 331 423, mit den be¬ reits benannten Nachteilen.EP-A 284 448 and EP-A 37 492 recommend the production of coated catalysts by the spray process already described, or by the process of GB-1 331 423, with the disadvantages already mentioned.
Das EP-B 293 859 offenbart ein Verfahren zur Herstellung von ku- gelförmigen Schalenkatalysatoren durch Anwendung einer zentrifu¬ galen Strömungs-Beschichtungsvorrichtung. Die Beschichtung er¬ folgt mittels einer Katalysatorvorläufermasse. Als Bindemittel empfiehlt das EP-B 293 859 z.B. Wasser, Alkohol und Aceton.EP-B 293 859 discloses a method for producing spherical coated catalysts by using a centrifugal flow coating device. The coating takes place by means of a catalyst precursor mass. EP-B 293 859 recommends e.g. Water, alcohol and acetone.
Nachteilig an der Lehre des EP-B 293 859 ist wiederum das Erfor¬ dernis einer Mitverwendung eines Bindemittels.A disadvantage of the teaching of EP-B 293 859 is again the need to use a binder.
Aus der DE-A 25 26 238 und der US-3 956 377 ist ein Verfahren zur Herstellung kugelförmiger Oxid-Schalenkatalysatoren bekannt, bei dem die Trägerkugeln zunächst mit Wasser oder anderen Flüssigkei¬ ten wie Petrolether als Bindemittel befeuchtet werden. Anschlie¬ ßend wird die katalytisch aktive Oxidmasse dadurch auf das mit Bindemittel angefeuchtete Trägermaterial aufgebracht, daß man das feuchte Trägermaterial in der pulverförmigen katalytisch aktiven Oxidmasse wälzt. Nachteilig an dieser Verfahrensweise ist wie¬ derum das Erfordernis einer Bindemittelmitverwendung sowie, daß die erreichbare Schalendicke durch das Bindemittelaufnahme¬ vermögen des Trägers beschränkt wird, da dieser seitens des Trä¬ gers aufgenommenen Bindemittelmenge die Bindung der gesamten auf- zunmehmenden pulverförmigen Oxidmasse obliegt. Ein weiterer Nach¬ teil der Methode besteht darin, daß der Befeuchtungsgrad der je¬ weiligen Oberflächenschicht während des Beschichtungsvorgangs ständig variiert. D.h., die Grundschicht trifft auf die Feuchte des unbeschichteten Trägers. Anschließend muß die Feuchtigkeit erst durch die Grundschicht an deren Oberfläche wandern, um wei¬ tere Aktivmasse anhaften zu können usw. Als Folge wird ein zwiebelartiger Schalenaufbau erhalten, wobei insbesondere die Aneinanderhaftung aufeinander folgender Schichten nicht zu be¬ friedigen vermag.DE-A 25 26 238 and US Pat. No. 3,956,377 disclose a process for producing spherical oxide coated catalysts in which the carrier balls are first moistened with water or other liquids such as petroleum ether as binders. Subsequently, the catalytically active oxide mass is applied to the carrier material moistened with binder by rolling the moist carrier material in the powdery catalytically active oxide mass. A disadvantage of this procedure is again the requirement that the binder be used and that the achievable shell thickness is limited by the binder absorption capacity of the carrier, since this amount of binder absorbed by the carrier is responsible for binding the entire powdery oxide mass to be absorbed. Another disadvantage of the method is that the degree of moistening of the respective surface layer varies continuously during the coating process. This means that the base layer meets the moisture of the uncoated substrate. Subsequently, the moisture first has to migrate through the base layer to its surface in order to be able to adhere further active composition, etc. As a result, an onion-like shell structure is obtained, the adherence of successive layers in particular not being satisfactory.
Die DE-A 29 09 671 versucht die Nachteile der ebenda beschriebe¬ nen Verfahrensweise dadurch zu mindern, daß die kugelförmigen Trägerkörper in einen geneigten rotierenden Drehteller gefüllt werden. Der rotierende Drehteller führt die kugelförmigen Träger- körper periodisch unter zwei in bestimmtem Abstand aufeinander¬ folgend angeordneten Dosiervorrichtungen hindurch. Die erste der beiden Dosiervorrichtungen entspricht einer Düse, durch die die Trägerkugeln mit Wasser besprüht und kontrolliert befeuchtet wer¬ den. Die zweite Dosiervorrichtung befindet sich außerhalb des Zerstäubungskegels des eingesprühten Wassers und dient dazu, feinteilige oxidische Aktivmasse zuzuführen. Die kontrolliert be- feuchteten Trägerkugeln nehmen das zugeführte Katalysatorpulver auf, das sich durch die rollende Bewegung auf der äußeren Ober¬ fläche der Trägerkugeln zu einer zusammenhängenden Schale ver¬ dichtet. Die so grundbeschichtete Trägerkugel durchläuft als so¬ zusagen neuer Trägerkörper im Verlauf der darauffolgenden Umdre- hung wiederum die Sprühdüse, wird dabei in gleicher Weise kon¬ trolliert befeuchtet, um im Verlauf der Weiterbewegung eine wei¬ tere Schicht feinteiliger oxidischer Aktivmasse aufnehmen zu kön¬ nen usw. Nachteilig an dieser Verfahrensweise ist, daß das als Bindemittel verwendete Wasser abschließend durch Einleiten von Heißluft wieder entfernt werden muß.DE-A 29 09 671 tries to alleviate the disadvantages of the procedure described above by filling the spherical carrier bodies into an inclined rotating turntable. The rotating turntable guides the spherical carrier bodies periodically under two metering devices arranged one after the other at a certain distance. The first of the two metering devices corresponds to a nozzle through which the Carrier balls are sprayed with water and moistened in a controlled manner. The second metering device is located outside the atomizing cone of the sprayed-in water and is used to supply finely divided oxidic active material. The controlled moistened carrier balls take up the supplied catalyst powder, which is compacted into a coherent shell by the rolling movement on the outer surface of the carrier balls. The carrier ball coated in this way, as it were a new carrier body, again passes through the spray nozzle in the course of the subsequent rotation, is moistened in a controlled manner in the same way in order to be able to take up a further layer of finely divided oxidic active material in the course of the further movement etc. A disadvantage of this procedure is that the water used as a binder must finally be removed by introducing hot air.
Die Lehre der DE-A 44 32 795 ist eine Weiterentwicklung der Lehre der DE-A 29 09 671 und unterscheidet sich von letzterer darin, daß als flüssiges Bindemittel eine wäßrige Lösung einer bei Nor- maldruck oberhalb von 100°C siedenden organischen Substanz verwendet wird.The teaching of DE-A 44 32 795 is a further development of the teaching of DE-A 29 09 671 and differs from the latter in that an aqueous solution of an organic substance boiling at normal pressure above 100 ° C. is used as the liquid binder .
Die vorgenannten, am Beispiel der katalytisch aktiven Oxidmassen gemachten, Ausführungen sind so im wesentlichen auch auf andere katalytisch aktiven Feststoffe übertragbar.The above-mentioned statements made using the example of the catalytically active oxide compositions can thus essentially also be transferred to other catalytically active solids.
Die Aufgabe der vorliegenden Erfindung bestand daher darin, ein Verfahren zur Herstellung eines Katalysators, bestehend aus einem Trägerkörper und einer auf der Oberfläche des Trägerkörpers auf- gebrachten katalytisch aktiven Masse, zur Verfügung zu stellen, das einerseits der Mitverwendung eines flüssigen Bindemittels nicht bedarf und andererseits die Nachteile des Plasmaspritz- oder Flammspritzverfahrens der DE-A 20 25 430 nicht aufweist.The object of the present invention was therefore to provide a process for producing a catalyst consisting of a support body and a catalytically active composition applied to the surface of the support body, which on the one hand does not require the use of a liquid binder and on the other hand does not have the disadvantages of the plasma spraying or flame spraying process of DE-A 20 25 430.
Demgemäß wurde ein Verfahren zur Herstellung eines Katalysators, bestehend aus einem Trägerkörper und einer auf der Oberfläche des Trägerkörpers aufgebrachten katalytisch aktiven Masse, gefunden, das dadurch gekennzeichnet ist, daß man die katalytisch aktive Masse oder eine Vorläufermassen derselben gemeinsam mit den Trägerkörpern in einen zylindrischen Behälter gibt und diesen so bewegt, daß seine Gesamtbewegung eine Suspension aus einer Dreh¬ bewegung des zylindrischen Behälters um seine eigene (zentrale) Längsachse (Bewegung 1) und einer Kreisbewegung dieser Längsachse (Bewegung 2) ist, mit der Maßgabe, daß die Richtung des Vektors der Winkelgeschwindigkeit der Bewe¬ gung 1 [ ω lj zur Richtung des Vektors der Winkelgeschwindig¬ keit der Bewegung 2 \ ω2j entgegengesetzt ist, 5 - der Betrag der kleineren der beiden Winkelgeschwindigkeiten wenigstens 50 %, vorzugsweise wenigstens 75 %, des Betrages der größeren der beiden Winkelgeschwindigkeiten ist,Accordingly, a process for the preparation of a catalyst consisting of a support body and a catalytically active composition applied to the surface of the support body has been found, which is characterized in that the catalytically active composition or a precursor composition thereof, together with the support bodies, is placed in a cylindrical container there and moves it so that its total movement is a suspension of a rotary movement of the cylindrical container about its own (central) longitudinal axis (movement 1) and a circular movement of this longitudinal axis (movement 2), with the proviso that the direction of the vector of the angular velocity of the movement 1 [ ω lj is opposite to the direction of the vector of the angular velocity of the movement 2 \ ω 2 j, 5 - the amount of the smaller of the two angular speeds is at least 50%, preferably at least 75%, the amount of the larger of the two angular velocities,
und im Fall der Verwendung einer Vorlaufentlasse die durch die Be- Q_Q wegung erzeugte Oberflächenbeschichtung der Trägerkörper abschließend aktiviert, z.B. im Fall einer Vorläufermasse einer katalytisch aktiven Oxidmasse calciniert (d.h. thermisch behan¬ delt) , wird.and activates the generated surface coating of the carrier body movement through the loading Q _ Q finally in the case of using a lead, Let, for example in the case of a precursor material of a catalytically active oxide material calcined (ie thermally behan¬ delt) is.
15 Vorzugsweise ist der Betrag der kleineren der beiden Winkelge¬ schwindigkeiten wenigstens 90, mit Vorteil wenigstens 95 % des Betrages der größeren der beiden Winkelgeschwindigkeiten. Mit be¬ sonderem Vorteil sind die Beträge der beiden Winkelgeschwindig¬ keiten ω1 , ω 2 gleich groß. Weiterhin ist es günstig, wenn dieThe amount of the smaller of the two angular speeds is preferably at least 90, advantageously at least 95% of the amount of the larger of the two angular speeds. The amounts of the two angular velocities ω 1 , ω 2 are of particular advantage with the same magnitude. Furthermore, it is favorable if the
20 Zentrifugalbeschleunigung der Bewegung 2 wenigstens das dreifache oder fünffache, mit Vorteil wenigstens das zehnfache der Erdbe¬ schleunigung beträgt. In der Regel wird die Zentrifugalbeschleu¬ nigung der Bewegung 2 wenigstens das zwanzig- oder wenigstens das dreißigfache der Erdbeschleunigung betragen. Üblicherweise über-20 centrifugal acceleration of movement 2 is at least three times or five times, advantageously at least ten times the acceleration due to gravity. As a rule, the centrifugal acceleration of movement 2 will be at least twenty or at least thirty times the acceleration due to gravity. Usually over-
25 schreitet die Zentrifugalbeschleunigung der Bewegung 2 das acht- zigfache der Erdbeschleunigung nicht. In der Regel wird die Zen¬ trifugalbeschleunigung der Bewegung 2 das fünfzigfache der Erdbe¬ schleunigung nicht überschreiten. Der Innendurchmesser des zylin¬ drischen Behälters beträgt in der Regel 10 bis 50, meist 20 bis25 the centrifugal acceleration of movement 2 does not exceed eighty times the gravitational acceleration. As a rule, the centrifugal acceleration of movement 2 will not exceed fifty times the acceleration due to gravity. The inner diameter of the cylindrical container is usually 10 to 50, usually 20 to
30 40 % des Durchmessers der Kreisbewegung der Längsachse des zylin¬ drischen Behälters. Selbstverständlich ist der Innendurchmesser des zylindrischen Behälters ein Vielfaches der Längstausdehnung (im Fall einer Kugel deren Durchmsesser) der Trägerkörper (in ty¬ pischer Weise das 10- bis 100-fache).30 40% of the diameter of the circular movement of the longitudinal axis of the cylindrical container. Of course, the inner diameter of the cylindrical container is a multiple of the longest dimension (in the case of a ball, its diameter) of the carrier body (typically 10 to 100 times).
3535
Die erfindungsgemäße Bewegungsform des die Trägerkörper und die auf selbige aufzubringende katalytisch aktive Masse, wie z.B. der katalytisch aktiven Oxidmasse, bzw. deren Vorläufermasse ent¬ haltenden zylindrischen Behälters gewährleistet zwischen beidenThe form of movement according to the invention of the carrier body and the catalytically active composition to be applied to it, such as e.g. the catalytically active oxide mass, or the cylindrical container containing its precursor mass, is guaranteed between the two
40 Materialien hohe Energieübertragungsdichten, die eine Grundlage dafür sind, daß auch ohne Mitverwendung eines flüssigen Binde¬ mittels die auf der Trägerkörperoberfläche aufzubringende Masse auf selbiger haftet. Der grundbeschichtete Trägerkörper fungiert im weiteren Verlauf quasi als neuer Trägerkörper etc. Durch ge- 4 0 materials high energy transfer densities, which are a basis for the fact that the mass to be applied to the surface of the carrier body adheres to it even without the use of a liquid binding agent. In the further course, the base-coated carrier body acts as a new carrier body, etc.
45 zielte Wahl des Verhältnisses von zu beschichtender Gesamtober¬ fläche und auf selbiger aufzubringender Materialmenge läßt sich die Schalendicke im wesentlichen nach Bedarf einstellen. Nach Beendigung der erfindungsgemäßen Bewegung des zylindrischen Be¬ hälters können selbigem die gleichförmig beschichteten Träger¬ körper entnommen werden.The targeted choice of the ratio of the total surface to be coated and the amount of material to be applied to the same can be adjusted essentially as required. To When the movement of the cylindrical container according to the invention has ended, the uniformly coated carrier bodies can be removed from the same.
In einfacher Weise läßt sich die erfindungsgemäße Bewegungsform des zylindrischen Behälters dadurch realisieren, daß man den zy¬ lindrischen Behälter auf einer horizontal rotierenden Sonnen- Scheibe befestigt und zur rotierenden Sonnenscheibe gegenläufig um seine eigene Längsachse dreht. Eine solche Anordnung ist z.B. in Gestalt von Planetenschnellmühlen käuflich erwerblich (vgl. SPRECHSAAL, Vol. 125, No. 7, 1992, S. 397 ff; cav 1993, Juni S. 98 ff; Planetenschnellmühle, Firmenschrift derThe form of movement of the cylindrical container according to the invention can be realized in a simple manner by attaching the cylindrical container to a horizontally rotating sun disk and rotating it in the opposite direction to its rotating longitudinal disk about its own longitudinal axis. Such an arrangement is e.g. commercially available in the form of high-speed planetary mills (see SPRECHSAAL, Vol. 125, No. 7, 1992, p. 397 ff; cav 1993, June, p. 98 ff; planetary high-speed mill, company publication of
Retsch GmbH & Co.KG in Haan 1, DE, 3/90, Nr. 99.528.0001) . In der Regel trägt die Sonnenscheibe einer solchen Planetenschnellmühle vier zylindrische Becher in einer Anordnung gemäß den Figuren 1 und 2 (entnommen aus SPRECHSAAL, Vol. 125, No. 7, 1992, S. 398 und S. 399).Retsch GmbH & Co.KG in Haan 1, DE, 3/90, No. 99.528.0001). As a rule, the sun disk of such a high-speed planetary mill carries four cylindrical cups in an arrangement according to FIGS. 1 and 2 (taken from SPRECHSAAL, Vol. 125, No. 7, 1992, p. 398 and p. 399).
Die Symbole in den Figuren 1 und 2 besitzen dabei folgende Bedeu- tung:The symbols in FIGS. 1 and 2 have the following meaning:
ri = Bewegungsradius des kugelförmigen Trägerkörpers im Pkt. A durch die Sonnenscheibendrehung; r2 = Bewegungsradius des kugelförmigen Trägerkörpers im Pkt. B durch die Sonnenscheibendrehung;ri = radius of movement of the spherical support body in point A through the rotation of the sun disk; r 2 = radius of movement of the spherical support body in point B through the rotation of the sun disk;
Fzs = Zentrifugalkraft durch Sonnenscheibendrehung;F zs = centrifugal force due to rotation of the sun disk;
FZP = Zentrifugalkraft durch Becherrotation;F ZP = centrifugal force by cup rotation;
FR = Reibkraft;F R = frictional force;
F COR = Corioliskraft; Rs = Radius der Becherachsenbewegung auf der Sonnenscheibe; F CO R = Coriolis force; R s = radius of the cup axis movement on the sun disk;
RP = Innenradius des Bechers; ωp = Winkelgeschwindigkeit der Becherrotation (Drehrichtung des Bechers) ; ω s = Winkelgeschwindigkeit der Sonnenscheibe (Drehrichtung der Sonnenscheibe) ;R P = inner radius of the cup; ω p = angular velocity of the cup rotation (direction of rotation of the cup); ω s = angular velocity of the sun disk (direction of rotation of the sun disk);
Aufgrund der entgegengesetzten Drehrichtung von Zylinderbecher und Trägerscheibe wirken die Zentrifugalkräfte abwechselnd gleich und gegensinnig. Daraus ergibt sich nacheinander ein Ablaufen der Trägerkörper an der Becherinnenwand und ein Abheben und freies Durchqueren von Beschichtungsgut und Trägerkörpern durch den In¬ nenraum des Bechers. Normalerweise ist der Zylinderbecher bei An¬ wendung des erfindungsgemäßen Verfahrens durch einen Deckel ge- schlössen. Die Materialien der Trägerkörper sind vorzugsweise chemisch in¬ ert, d.h. , sie greifen in den Ablauf der chemischen Umsetzung, z.B. der Gasphasenoxidation, die durch die erfindungsgemäß herge¬ stellten Schalenkatalysatoren katalysiert wird, im wesentlichen nicht ein. Als Materialien für die Trägerkörper kommen erfindungsgemäß insbesondere Aluminiumoxid, Siliciumdioxid, Sili- cate wie Ton, Kaolin, Steatit, Bims, Aluminiumsilicat und Magne- siumsilicat, Siliciumcarbid, Zirkondioxid und Thoriumdioxid in Betracht.Due to the opposite direction of rotation of the cylinder cup and carrier disc, the centrifugal forces act alternately in the same and opposite directions. This results in successive running of the support bodies on the inner wall of the cup and lifting and free passage through the coating material and support bodies through the interior of the cup. When using the method according to the invention, the cylinder cup is normally closed by a cover. The materials of the support bodies are preferably chemically inert, ie they essentially do not intervene in the course of the chemical reaction, for example gas phase oxidation, which is catalyzed by the coated catalysts produced according to the invention. According to the invention, aluminum oxide, silicon dioxide, silicates such as clay, kaolin, steatite, pumice, aluminum silicate and magnesium silicate, silicon carbide, zirconium dioxide and thorium dioxide are particularly suitable as materials for the carrier bodies.
Mit Vorteil ist die Oberfläche des Trägerkörpers rauh, da eine erhöhte Oberflächenrauhigkeit in der Regel eine erhöhte Haft¬ festigkeit der aufgebrachten Schale an oxidischer Aktivmasse be¬ dingt. Vorzugsweise liegt die Oberflächenrauhigkeit Rz des Träger- körpers im Bereich von 40 bis 500 μm, vorzugsweise 40 bis 200 μm (bestimmt gemäß DIN 4768 Blatt 1 mit einem "Hommel Tester für DIN-ISO Oberflächenmeßgrößen" der Fa. Hommelwerke) . Die Träger¬ materialien können porös oder unporös sein. Häufig ist das Trägermaterial unporös (Gesamtvolumen der Poren auf das Volumen des Trägerkörpers bezogen < 1 Vol.-%) .The surface of the carrier body is advantageously rough, since an increased surface roughness generally causes an increased adhesive strength of the applied shell to oxidic active material. The surface roughness R z of the carrier body is preferably in the range from 40 to 500 μm, preferably 40 to 200 μm (determined in accordance with DIN 4768 Sheet 1 using a “Hommel Tester for DIN-ISO surface measurement parameters” from Hommelwerke). The carrier materials can be porous or non-porous. The carrier material is often non-porous (total volume of the pores based on the volume of the carrier body <1% by volume).
Prinzipiell kommen für das erfindungsgemäße Verfahren beliebige Geometrien der Trägerkörper in Betracht. Ihre Längstausdehnung beträgt in der Regel 1 bis 10 mm. Vorzugsweise werden jedoch Ku- geln oder Zylinder, insbesondere Hohlzylinder, als Trägerkörper angewendet.In principle, any geometries of the carrier bodies can be considered for the method according to the invention. Their longest dimension is usually 1 to 10 mm. However, balls or cylinders, in particular hollow cylinders, are preferably used as carrier bodies.
Werden Zylinder als Trägerkörper verwendet, so beträgt deren Länge vorzugsweise 2 bis 10 mm und ihr Außendurchmesser bevorzugt 4 bis 10 mm. Im Fall von Ringen liegt die Wanddicke darüber hin¬ aus üblicherweise bei 1 bis 4 mm. Besonders bevorzugte ringför¬ mige Trägerkörper besitzen eine Länge von 3 bis 6 mm, einen Außendurchmesser von 4 bis 8 mm und eine Wanddicke von 1 bis 2 mm. Ganz besonders bevorzugt sind Ringe der Geometrie 7 mm x 3 mm x 4 mm (Außendurchmesser x Länge x Innendurchmesser) .If cylinders are used as carrier bodies, their length is preferably 2 to 10 mm and their outside diameter is preferably 4 to 10 mm. In the case of rings, the wall thickness is usually 1 to 4 mm. Particularly preferred ring-shaped carrier bodies have a length of 3 to 6 mm, an outer diameter of 4 to 8 mm and a wall thickness of 1 to 2 mm. Rings of geometry 7 mm x 3 mm x 4 mm (outer diameter x length x inner diameter) are very particularly preferred.
Die Dicke der erfindungsgemäß auf den Trägerkörper aufgebrachten katalytisch aktiven Masse, wie z.B. der katalytisch aktiven Oxid- masse, bzw. deren Voläufermasse liegt zweckmäßigerweise in der Regel bei 5 nm bis 1000 um. Bevorzugt sind, insbesondere bei ring¬ förmigen Trägerkörpern, 10 nm bis 500 um, besonders bevorzugt 100 nm bis 500 μm und ganz besonders bevorzugt 200 nm bis 300 μm. Die Feinheit der auf die Oberfläche des Trägerkörpers aufzu¬ bringenden katalytisch aktiven Masse, wie z.B. der katalytisch aktiven Oxidmasse, wird selbstredend an die gewünschte Schalen- dicke angepaßt. Zur Erzielung einer erhöhten Schalendicke kann das erfindungsgemäße Verfahren periodisch wiederholt werden.The thickness of the catalytically active composition, such as, for example, the catalytically active oxide composition, applied to the support body according to the invention, or the volume thereof, is expediently as a rule from 5 nm to 1000 μm. 10 nm to 500 μm, particularly preferably 100 nm to 500 μm and very particularly preferably 200 nm to 300 μm, are preferred, in particular in the case of ring-shaped carrier bodies. The fineness of the catalytically active mass to be applied to the surface of the carrier body, such as the catalytically active oxide mass, is of course applied to the desired shell. adjusted thickness. The method according to the invention can be repeated periodically to achieve an increased shell thickness.
Der wesentliche Vorzug des erfindungsgemäßen Verfahrens besteht darin, daß es der nachträglichen Entfernung eines flüssigenThe main advantage of the method according to the invention is that it is the subsequent removal of a liquid
Bindemittels nicht bedarf, was eine Reaktion mit dem meist orga¬ nischen Bindemittel ausschließt. Außerdem muß das zur Beschich¬ tung eingesetzte Material nicht in notwendiger Weise bereits in feinteiliger Form eingesetzt werden. Vielmehr kann durchaus von grobteiligern Ausgangsmaterial ausgegangen werden, daß bei geei¬ gneter Wahl der Trägerkörper bei Anwendung des erfindungsgemäßen Verfahrens einem Mahlprozeß unterliegt, bis bei Erreichen der er¬ forderlichen Feinheit die sich entwickelnden Van der Waals Kräfte ein Aufziehen auf die Oberfläche des Trägerkörpers ermöglichen. Ein ansonsten erforderlicher separater Mahlprozeß kann entfallen.Binder does not need, which excludes a reaction with the mostly organic binder. In addition, the material used for coating does not necessarily have to be used in finely divided form. Rather, it can be assumed that the starting material is of a coarse particle size, that if the carrier body is selected appropriately, the process according to the invention is subject to a milling process until the Van der Waals forces that are developed enable the force to be drawn up onto the surface of the carrier body. An otherwise required separate grinding process can be omitted.
Ein weiteres wesentliches Merkmal des erfindungsgemäßen Verfah¬ rens ist, daß auf den Trägerkörper sowohl die katalytisch aktive oxidische Masse als solche, als auch eine Vorlaufentlasse dersel- ben aufgetragen werden kann.A further essential feature of the method according to the invention is that both the catalytically active oxidic mass as such and also a preliminary discharge of the same can be applied to the carrier body.
Zur Herstellung von katalytisch aktiven oxidischen Massen geht man üblicherweise von in an sich bekannter Weise geeigneten Quel¬ len der katalytisch aktiven, oxidischen Massen aus und erzeugt aus diesen ein möglichst inniges, vorzugsweise feinteiliges,For the production of catalytically active oxidic masses, it is customary to start from sources of the catalytically active, oxidic masses which are suitable in a manner known per se and to produce an intimate, preferably finely divided,
Trockengemisch (das als Vorläufermasse auf die Trägerkörperober¬ fläche aufgebracht werden kann) , welches dann der Calcinierung (thermische Behandlung) unterworfen und gegebenenfalls durch Mah¬ len in feinteilige Form überführt wird. Wird bereits die Vorlaufentlasse aufgetragen, wird nach beendeter Auftragung calci- niert. Dies führt in der Regel zu Schalenkatalysatoren mit erhöhter spezifischer Oberfläche der Aktivmasse.Dry mixture (which can be applied as a precursor mass to the surface of the carrier body), which is then subjected to the calcination (thermal treatment) and, if appropriate, converted into finely divided form by grinding. If the pre-discharge is already applied, the application is calculated after the application has been completed. This usually leads to coated catalysts with an increased specific surface area of the active composition.
Wesentlich ist, wie allgemein bekannt, nur, daß es sich bei den Quellen entweder bereits um Oxide handelt, oder um solcheIt is only essential, as is generally known, that the sources are either already oxides or such
Verbindungen, die durch Erhitzen, wenigstens in Anwesenheit von Sauerstoff, in Oxide überführbar sind. Neben den Oxiden kommen daher als Ausgangsverbindungen vor allem Halogenide, Nitrate, Formiate, Oxalate, Acetate, Carbonate oder Hydroxide in Betracht.Compounds which can be converted into oxides by heating, at least in the presence of oxygen. In addition to the oxides, halides, nitrates, formates, oxalates, acetates, carbonates or hydroxides are therefore particularly suitable as starting compounds.
Das innige Vermischen der Ausgangsverbindungen kann in trockener oder in nasser Form erfolgen. Erfolgt es in trockener Form, wer¬ den die Ausgangsverbindungen zweckmäßigerweise als feinteilige Pulver eingesetzt und nach Mischen und gegebenenfalls Verpressen der Calcinierung unterworfen. Vorzugsweise erfolgt das innige Vermischen jedoch in nasser Form. Üblicherweise werden die Ausgangsverbindungen dabei in Form einer wäßrigen Lösung oder Suspension miteinander vermischt. Anschließend wird die wäßrige Masse getrocknet und nach Trocknung calciniert. Vorzugsweise er¬ folgt der Trocknungsprozeß durch Sprühtrocknung. Das dabei anfal¬ lende Pulver erweist sich für eine unmittelbare Weiterverarbei- tung häufig als zu feinteilig. In diesen Fällen kann es unter Zu¬ satz von Wasser geknetet werden. Die anfallende Knetmasse wird anschließend der Calcinierung unterworfen und danach zu einer feinteiligen oxidischen Aktivmasse gemahlen.The intimate mixing of the starting compounds can take place in dry or in wet form. If it is carried out in dry form, the starting compounds are expediently used as finely divided powders and, after mixing and optionally pressing, are subjected to the calcination. However, the intimate mixing is preferably carried out in wet form. The starting compounds are usually in the form of an aqueous solution or S uspension mixed together. The aqueous mass is then dried and, after drying, calcined. The drying process is preferably carried out by spray drying. The case anfal ¬ loin powder turns out for immediate further processing often be too finely divided. In these cases, it can be kneaded with the addition of water. The modeling clay obtained is then subjected to the calcination and then ground to a finely divided oxidic active composition.
Die Calcinationsbedingungen sind dem Fachmann für die verschiede¬ nen möglichen oxidischen Aktivmassen an sich bekannt.The calcination conditions are known per se to the person skilled in the art for the various possible oxidic active compositions.
Günstig ist das erfindungsgemäße Verfahren im Fall von Mo und V bzw. Mo, Fe und Bi enthaltenden Multimetalloxidmassen.The process according to the invention is favorable in the case of multimetal oxide compositions containing Mo and V or Mo, Fe and Bi.
Als besonders vorteilhaft erweist sich das erfindungsgemäße Ver¬ fahren im Fall von als Schale aufzubringenden aktiven Multimetal- loxiden der allgemeinen Stöchiometrie IThe method according to the invention proves to be particularly advantageous in the case of active multimetal oxides of general stoichiometry I to be applied as a shell
Mθι2VaX1X2X3X4χ5χ6θn (j ) b c d e f gMθι 2 V a X 1 X 2 X 3 X 4 χ5χ6θ n (j ) bcdefg
in der die Variablen folgende Bedeutung haben:in which the variables have the following meaning:
X1 W, Nb, Ta, Cr und/oder Ce,X 1 W, Nb, Ta, Cr and / or Ce,
X2 Cu, Ni, Co, Fe, Mn und/oder Zn,X 2 Cu, Ni, Co, Fe, Mn and / or Zn,
X3 Sb und/oder Bi,X 3 Sb and / or Bi,
X4 wenigstens eines oder mehrere Alkalimetalle,X 4 at least one or more alkali metals,
X5 wenigstens eines oder mehrere Erdalkalimetalle, X6 Si, AI, Ti und/oder Zr, a 1 bis 6, b 0,2 bis 4, c 0,5 bis 18, d 0 bis 40, e 0 bis 2, f 0 bis 4, g 0 bis 40 und n eine Zahl, die durch die Wertigkeit und Häufigkeit der von Sauerstoff verschiedenen Elemente in I bestimmt wird.X 5 at least one or more alkaline earth metals, X 6 Si, Al, Ti and / or Zr, a 1 to 6, b 0.2 to 4, c 0.5 to 18, d 0 to 40, e 0 to 2, f 0 to 4, g 0 to 40 and n a number which is determined by the valency and frequency of the elements other than oxygen in I.
Die Herstellung von aktiven Multimetalloxiden I einschließlich der Calcinationsbedingungen beschreibt die DE-A 43 35 973. Die DE-A 43 35 973 offenbart auch bevorzugte Ausführungsformen inner¬ halb der aktiven Multimetalloxide I. Zu diesen zählen beispiels- weise jene Multimetalloxide I, die von nachfolgenden Bedeutungen der Variablen der allgemeinen Formel I erfaßt werden: χi W, Nb und/oder Cr,DE-A 43 35 973 describes the preparation of active multimetal oxides I, including the calcination conditions. DE-A 43 35 973 also discloses preferred embodiments within active multimetal oxides I. These include, for example, those multimetal oxides I that are described below Meanings of the variables of the general formula I are recorded: χi W, Nb and / or Cr,
X2 Cu, Ni, Co und/oder Fe,X 2 Cu, Ni, Co and / or Fe,
X3 Sb,X 3 Sb,
X4 Na und/oder K, X5 Ca, Sr und/oder Ba,X 4 Na and / or K, X 5 Ca, Sr and / or Ba,
X6 Si, AI und/ oder Ti, a 2,5 bis 5, b 0,5 bis 2, c 0,5 bis 3 , d 0 bis 2, e 0 bis 0,2, f 0 bis 1, g 0 bis 15 und n eine Zahl, die durch die Wertigkeit und Häufigkeit der von Sauerstoff verschiedenen Elemente in I bestimmt wird.X 6 Si, Al and / or Ti, a 2.5 to 5, b 0.5 to 2, c 0.5 to 3, d 0 to 2, e 0 to 0.2, f 0 to 1, g 0 to 15 and n is a number which is determined by the valency and frequency of the elements in I other than oxygen.
Ganz besonders bevorzugte Multimetalloxide I sind jedoch jene der allgemeinen Formel I'However, very particularly preferred multimetal oxides I are those of the general formula I '
Mo12VaX1X2X5X6On (I'),Mo 12 V a X 1 X 2 X 5 X 6 O n ( I ' ) ,
mitWith
X1 W und/oder Nb,X 1 W and / or Nb,
X2 Cu und/oder Ni,X 2 Cu and / or Ni,
X5 Ca und/oder Sr,X 5 Ca and / or Sr,
X6 Si und/oder AI, a 3 bis 4,5, b 1 bis 1,5, c 0,75 bis 2,5, f 0 bis 0,5, g 0 bis 8 und n eine Zahl, die durch die Wertigkeit und Häufigkeit der von Sauerstoff verschiedenen Elemente in I' bestimmt wird.X 6 Si and / or AI, a 3 to 4.5, b 1 to 1.5, c 0.75 to 2.5, f 0 to 0.5, g 0 to 8 and n a number represented by the Value and frequency of elements other than oxygen is determined in I '.
Mit den aktiven Multimetalloxiden I erfindungsgemäß hergestellte Schalenkatalysatoren eignen sich insbesondere zur gasphasenkata- lytisch oxidativen Herstellung von Acrylsäure aus Acrolein. Dies gilt insbesondere für kugel- oder ringförmige Schalenkataly¬ satoren. Vor allem dann, wenn diese die in dieser Schrift als be¬ vorzugt beschriebene Charakteristik (Geometrie, Schalendicke etc.) aufweisen. Die allgemeinen Reaktionsbedingungen für die gasphasenkatalytische Oxidation von Acrolein zu Acrylsäure finden sich ebenfalls in der DE-A 43 35 973. Das erfindungsgemäße Verfahren eignet sich auch im Fall von akti¬ ven Multimetalloxiden wie sie für die katalytische Gasphasen¬ oxidation von Methacrolein zu Methacrylsäure angewendet werden und z.B. in der DE-A 40 22 212 beschrieben sind.Shell catalysts produced according to the invention with the active multimetal oxides I are particularly suitable for the gas-phase catalytically oxidative production of acrylic acid from acrolein. This applies in particular to spherical or ring-shaped shell catalysts. Especially if they have the characteristics (geometry, shell thickness, etc.) described as preferred in this document. The general reaction conditions for the gas phase catalytic oxidation of acrolein to acrylic acid can also be found in DE-A 43 35 973. The process according to the invention is also suitable in the case of active multimetal oxides as are used for the catalytic gas phase oxidation of methacrolein to methacrylic acid and are described, for example, in DE-A 40 22 212.
Weiterhin erweist sich das erfindungsgemäße Verfahren im Fall von als Schale aufzubringenden aktiven Multimetalloxiden der allge¬ meinen Stöchiometrie IIFurthermore, the method according to the invention proves itself in the case of active multimetal oxides of general stoichiometry II to be applied as a shell
Mo12BiaFebχlχ2X3χ4θn .__. c d e f (11) 'Mo 12 Bi a Fe b χlχ 2 X 3 χ4θ n .__. cdef (11) '
in der die Variablen nachfolgende Bedeutung aufweisen:in which the variables have the following meaning:
X1 Nickel und/oder Kobalt,X 1 nickel and / or cobalt,
X2 Thallium, ein Alkalimetall und/oder ein Erdalkalimetall,X 2 thallium, an alkali metal and / or an alkaline earth metal,
X3 Phosphor, Arsen, Bor, Antimon, Zinn, Cer, Blei, Niob und/oderX 3 phosphorus, arsenic, boron, antimony, tin, cerium, lead, niobium and / or
Wolfram, X4 Silicium, Aluminium, Titan und/oder Zirkonium, a 0,5 bis 5, b 0, 01 bis 3, c 3 bis 10, d 0,02 bis 2, e 0 bis 5, f 0 bis 10 und n eine Zahl, die durch die Wertigkeit und Häufigkeit der von Sauerstoff verschiedenen Elemente in II bestimmt wird, als geeignet.Tungsten, X 4 silicon, aluminum, titanium and / or zirconium, a 0.5 to 5, b 0, 01 to 3, c 3 to 10, d 0.02 to 2, e 0 to 5, f 0 to 10 and n a number, which is determined by the valency and frequency of the elements other than oxygen in II, as suitable.
Die Herstellung von aktiven Multimetalloxiden II einschließlich der Calcinationsbedingungen beschreibt die DE-A 40 23 239.DE-A 40 23 239 describes the production of active multimetal oxides II, including the calcination conditions.
Mit den aktiven Multimetalloxiden II erfindungsgemäß hergestellte Schalenkatalysatoren eignen sich insbesondere zur gasphasenkata- lytisch oxidativen Herstellung von Acrolein aus Propen. Dies gilt insbesondere für kugel- oder ringförmige Schalenkatalysatoren. Vor allem dann, wenn diese die in dieser Schrift als bevorzugt beschriebene Charakteristik (Geometrie, Schalendicke etc.) auf¬ weisen. Die allgemeinen Reaktionsbedingungen für die gasphasen- katalytische Oxidation von Propen zu Acrolein finden sich eben¬ falls in der DE-A 40 23 239 sowie in der DE-A 44 31 957.Shell catalysts produced according to the invention with the active multimetal oxides II are particularly suitable for the gas-phase catalytic oxidative production of acrolein from propene. This applies in particular to spherical or ring-shaped coated catalysts. Especially if they have the characteristic (geometry, shell thickness, etc.) described as preferred in this document. The general reaction conditions for the gas-phase catalytic oxidation of propene to acrolein can also be found in DE-A 40 23 239 and in DE-A 44 31 957.
Die vorgenannten Schalenkatalysatoren der aktiven Multimetallo¬ xide II eigenen sich aber auch zur gasphasenkatalytisch oxidativen Herstellung von Methacrolein aus tert. -Butanol, iso¬ Butan, iso-Buten oder tert. -Butylmethylether. Die allgemeinen Reaktionsbedingungen für diese katalytische Gasphasenoxidation finden sich z.B. in der DE-A 40 23 239 und in der DE-A 43 35 172.However, the aforementioned shell catalysts of the active multimetal oxides II are also suitable for the gas-phase catalytically oxidative production of methacrolein from tert. -Butanol, isobutane, isobutene or tert. -Butyl methyl ether. The general Reaction conditions for this catalytic gas phase oxidation can be found, for example, in DE-A 40 23 239 and in DE-A 43 35 172.
Weiterhin eignet sich das erfindungsgemäße Verfahren im Fall der aktiven Oxidmassen der DE-A 44 05 514.Furthermore, the method according to the invention is suitable in the case of the active oxide compositions of DE-A 44 05 514.
Selbstverständlich eignet sich das erfindungsgemäße Verfah¬ ren aber ganz generell zur Herstellung von Schalenkatalysatoren auf der Basis aktiver Massen, insbesondere für die in dieser Schrift im Rahmen der Würdigung des Standes der Technik aufge¬ führten katalysierten Reaktionen. Dies gilt auch dann, wenn die Aktivmasse eine oxidische Aktivmasse ist, die neben Sauerstoff lediglich ein anderes Element umfaßt. Insbesondere eignet sich das erfindungsgemäße Verfahren zur Herstellung von Schalenkataly- satorversuchsmengen für Schalenkatalysator-screening.Of course, the process according to the invention is very generally suitable for producing coated catalysts based on active compositions, in particular for the catalyzed reactions listed in this document in the context of the assessment of the prior art. This also applies if the active composition is an oxidic active composition which only comprises another element in addition to oxygen. In particular, the method according to the invention is suitable for the production of shell catalyst test quantities for shell catalyst screening.
BeispieleExamples
Herstellung von Schalenkatalysatoren in Anwendung des erfindungs- gemäßen VerfahrensProduction of coated catalysts using the process according to the invention
Zur Anwendung des erfindungsgemäßen Verfahrens wurde eine Anord¬ nung gemäß der Figuren 1, 2 verwendet mitAn arrangement according to FIGS. 1, 2 was used to apply the method according to the invention
Rp = Innenradius des Zylinderbechers = 5 cm;R p = inner radius of the cylinder cup = 5 cm;
H = Höhe des Zylinderbechers = 10 cm;H = height of the cylinder cup = 10 cm;
(üp = Betrag der Winkelgeschwindigkeit des Zylinderbechers = ωΞ = Betrag der Winkelgeschwindigkeit der Sonnenscheibe;(ü p = amount of the angular velocity of the cylinder cup = ω Ξ = amount of the angular velocity of the sun disk;
Rs = Radius der Zylinderbecherachsenbewegung auf der Sonnen- Scheibe = 15 cm;R s = radius of the cylinder cup axis movement on the sun disk = 15 cm;
Umdrehungen U der Sonnenscheibe pro Minute: zwischen 200 und 275.Revolutions U of the sun disk per minute: between 200 and 275.
Als Trägerkörper wurden entweder glatte Steatitkugeln mit Durch¬ messer = 1 mm oder oberflächenrauhe Staatitkugeln (Oberflachen- rauhigkeit Rz = 0,5 mm infolge Besplittung) mit Durchmesser = 2 mm verwendet.Either smooth steatite spheres with a diameter of 1 mm or surface-rough stateite spheres (surface roughness R z = 0.5 mm due to splitting) with a diameter of 2 mm were used as carrier bodies.
Als aufzubringende Oxidmassen wurden eingesetzt:The following oxide masses were used:
Oxid mittlerer Korngrößtdurchmesser [μm]Medium grain size diameter oxide [μm]
AgV03 0,5AgV0 3 0.5
CuSb206 1,2CuSb 2 0 6 1.2
Sr02 0,7Sr0 2 0.7
Ba02 1,0 Bi2Sr2CaιCu20n 2,0Ba0 2 1.0 Bi 2 Sr 2 CaιCu 2 0 n 2.0
BiιPbιSr2Ca2Cu30n 1,5BiιPbιSr2Ca 2 Cu 3 0n 1.5
NdιBa2Cu3On 0,6 SmιBa2Cu3On 1,8NdιBa 2 Cu 3 O n 0.6 SmιBa 2 Cu 3 O n 1.8
Y!Ba2Cu3On 1,1Y ! Ba 2 Cu 3 O n 1.1
LP-CuMθ04 0,9LP-CuMθ0 4 0.9
Culro25Mo0,5Wo,5θn 0,7 CÜMθ0,6Wθ,4θn 0,5Cu lr o 25 Mo 0 , 5Wo, 5θn 0.7 CÜMθ 0 , 6Wθ, 4θn 0.5
CUιMθ0/75Wo,25θn 1,6
Figure imgf000017_0001
CUιMθ 0/75 weeks, 25 θn 1.6
Figure imgf000017_0001
Nachfolgende Tabelle weist die verschiedenen erzielten Ergebnisse in Abhängigkeit von der Art und Menge des verwendeten Oxids,The following table shows the different results obtained depending on the type and amount of the oxide used,
Trägerkörpers, Bewegungsdauer und Umdrehungen je Minute der Son¬ nenscheibe aus. Alle Angaben beziehen sich auf einen (1) Zylin¬ derbecher. Die Angabe der Menge der aufgebrachten Oxidschicht er¬ folgt dabei in Gew. -%, bezogen auf die Trägerkugeleinwaage. Carrier body, duration of movement and revolutions per minute of the sun disk. All information relates to one (1) cylinder cup. The amount of the oxide layer applied is given in% by weight, based on the weight of the carrier ball.
Tabelle voTable vo
∞∞
Ci
Figure imgf000018_0002
H
Figure imgf000018_0001
Ci
Figure imgf000018_0002
H
Figure imgf000018_0001
O 00 O 00

Claims

Patentansprüche claims
1. Verfahren zur Herstellung eines Katalysators, bestehend aus 5 einem Trägerkörper und einer auf der Oberfläche des Träger- körpers aufgebrachten katalytisch aktiven Masse, das dadurch gekennzeichnet ist, daß man die katalytisch aktive Masse oder eine Vorläufermasse derselben gemeinsam mit den Trägerkörpern in einen zylindrischen Behälter gibt und diesen so bewegt, 0 daß seine Gesamtbewegung eine Superposition aus einer Drehbe¬ wegung des zylindrischen Behälters um seine eigene Längsachse (Bewegung 1) und einer Kreisbewegung dieser Längsachse (Bewe¬ gung 2) ist, mit der Maßgabe, daß1. A process for producing a catalyst consisting of 5 a support body and a catalytically active composition applied to the surface of the support body, which is characterized in that the catalytically active composition or a precursor composition thereof together with the support bodies in a cylindrical container and moves it so that its total movement is a superposition of a rotary movement of the cylindrical container about its own longitudinal axis (movement 1) and a circular movement of this longitudinal axis (movement 2), with the proviso that
5 - die Richtung des Vektors der Winkelgeschwindigkeit der Bewegung 1 { ω ι ) zur Richtung des Vektors der Winkelge¬ schwindigkeit der Bewegung 2 ( ω 2j entgegengesetzt ist, der Betrag der kleineren der beiden Winkelgeschwindigkei- Q ten wenigstens 50 % des Betrages der größeren der beiden5 - the direction of the vector of the angular velocity of the movement 1 {ω ι) speed to the direction of the vector of Winkelge¬ the movement 2 (ω 2 is opposite to j, the amount of the smaller of the two Winkelgeschwindigkei- Q th at least 50% of the amount of the larger of both
Winkelgeschwindigkeiten ist,Angular velocities is
und im Fall der Verwendung einer Vorläufermasse die durch die Bewegung erzeugte Oberflächenbeschichtung der Trägerkörper 5 abschließend aktiviert wird.and in the case of using a precursor mass, the surface coating of the carrier bodies 5 generated by the movement is finally activated.
2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß der Betrag der kleineren der beiden Winkelgeschwindigkeiten we¬ nigstens 75 % des Betrages der größeren der beiden Winkelge- Q schwindigkeiten ist.2. The method according to claim 1, characterized in that the amount of the smaller of the two angular velocities we¬ nigstens 75% of the amount of the larger of the two Winkelge- Q speeds.
3. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß der Betrag der beiden Winkelgeschwindigkeiten im wesentlichen gleich groß ist. 53. The method according to claim 1, characterized in that the amount of the two angular velocities is substantially the same. 5
4. Verfahren nach einem der Ansprüche 1 bis 3, dadurch gekenn¬ zeichnet, daß die Zentrifugalbeschleunigung der Bewegung 2 wenigstens das dreifache der Erdbeschleunigung beträgt.4. The method according to any one of claims 1 to 3, characterized gekenn¬ characterized in that the centrifugal acceleration of the movement 2 is at least three times the acceleration due to gravity.
0 5. Verfahren nach einem der Ansprüche 1 bis 4, dadurch gekenn¬ zeichnet, daß die auf die Oberfläche des Trägerkörpers aufge¬ brachte katalytisch aktive Masse eine katalytisch aktive Oxidmasse ist.5. The method according to one of claims 1 to 4, characterized in that the catalytically active composition applied to the surface of the support body is a catalytically active oxide composition.
5 5
6. Verfahren nach einem der Ansprüche 1 bis 4, dadurch gekenn¬ zeichnet, daß die auf die Oberfläche des Trägerkörpers aufge¬ brachte Masse die Vorlaufentlasse einer katalytisch aktiven Oxidmasse ist und die mit ihr erzeugte Oberflächenbeschich- tung der Trägerkörper abschließend durch Calcinieren akti¬ viert wird.6. The method according to any one of claims 1 to 4, characterized gekenn¬ characterized in that the applied auf¬ on the surface of the carrier body mass is the preliminary discharge of a catalytically active oxide mass and the surface coating generated with it of the carrier body is finally activated by calcining becomes.
7. Schalenkatalysator-screening, dadurch gekennzeichnet, daß die zu überprüfenden Schalenkatalysatorversuchsmengen nach einem Verfahren gemäß einem der Ansprüche 1 bis 6 hergestellt wer¬ den. 7. Shell catalyst screening, characterized in that the shell catalyst test quantities to be checked are produced by a method according to one of claims 1 to 6.
PCT/EP1997/002819 1996-06-12 1997-05-30 Process for producing a catalyst consisting of a substrate and a catalytically active compound applied to the upper surface of said substrate WO1997047387A1 (en)

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DE10059922A1 (en) * 2000-12-01 2002-06-20 Hte Ag The High Throughput Exp Process for applying layers of material to moldings
DE10061555A1 (en) 2000-12-11 2002-06-20 Basf Ag Shell catalyst for the hydrogenation of maleic anhydride and related compounds to gamma-butyrolactone and tetrahydrofuran and derivatives thereof
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US7022643B2 (en) 2002-08-20 2006-04-04 Nippon Shokubai Co., Ltd. Production process for catalyst
US20040038820A1 (en) * 2002-08-20 2004-02-26 Nippon Shokubai Co., Ltd. Production process for catalyst
JP4295521B2 (en) 2003-02-13 2009-07-15 株式会社日本触媒 Catalyst for producing acrylic acid and method for producing acrylic acid
ES2573254T3 (en) 2006-12-13 2016-06-06 Basf Se Microcapsules
WO2009112467A1 (en) 2008-03-11 2009-09-17 Basf Se Microcapsules with acylurea walls
KR20120046166A (en) 2009-06-15 2012-05-09 바스프 에스이 Microcapsules having highly branched polymers as cross-linking agents
KR101812351B1 (en) 2009-07-10 2017-12-26 바스프 에스이 Microcapsules having polyvinyl monomers as cross-linking agents
WO2011089106A1 (en) 2010-01-25 2011-07-28 Basf Se Method for producing phenolsulfonic acid aldehyde condensation products and the use thereof as desiccants
US9181466B2 (en) 2011-02-16 2015-11-10 Basf Se Microcapsules with a paraffin composition as capsule core
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