WO1999029426A1

WO1999029426A1 - Moulded body comprising an inert support and at least one porous oxidic material

Info

Publication number: WO1999029426A1
Application number: PCT/EP1998/007603
Authority: WO
Inventors: Georg Heinrich Grosch; Ulrich Müller; Andreas Walch; Norbert Rieber; Wolfgang Harder
Original assignee: Basf Aktiengesellschaft
Priority date: 1997-12-10
Filing date: 1998-11-25
Publication date: 1999-06-17
Also published as: EP1039969A1; ZA9811261B; JP2001525248A; AU1964099A; CA2314233A1; ID25488A; DE19754924A1; CN1284899A; KR20010032966A

Abstract

The invention relates to a moulded body comprising an inert support and at least one porous oxidic material applied to said support. The inventive moulded body is obtained by applying a mixture containing the at least one porous oxidic material and at least one metal acid ester or a hydrolyzate thereof or a combination of metal acid esters and hydrolyzate thereof to the inert support.

Description

Shaped body comprising an inert carrier and at least one porous oxidic material

The present invention relates to a shaped body comprising an inert carrier and applied to it at least one porous oxidic material, a process for its production and its use for the conversion of organic compounds, in particular for the epoxidation of organic compounds with at least one C-C double bond. The molded body described here has excellent abrasion resistance and excellent mechanical properties and is inexpensive compared to catalysts previously used for these purposes.

Abrasion-resistant molded articles made from catalytically active compositions are used in many chemical processes, in particular in processes using a fixed bed.

As a rule, for the production of solids, the catalytically active mass, ie the porous oxidic material, is mixed with a binder, an organic viscosity-increasing compound and a liquid to increase the mass and compacted in a mixing or kneading device or an extruder. The resulting plastic mass is then deformed, in particular using an extruder or an extruder. The resulting moldings are dried and calcined. A number of inorganic compounds are used as binders.

Thus, according to US Pat. No. 5,430,000, titanium dioxide or titanium dioxide hydrate is used as the binder. Other binders mentioned in the prior art include:

Alumina hydrate or other aluminum-containing binders

(WO 94/29408);

Mixtures of silicon and aluminum compounds (WO 94/13584); Silicon compounds (EP-A 0 592 050);

Clay minerals (JP-A 03 037 156);

Alkoxysilanes (EP-B 0 102 544).

An overview of the further related prior art is provided by DE 197 23 751.7.

When carrying out reactions with very high intrinsic reaction rates, the yield obtained industrially is limited by the diffusion of the starting materials or products in the shaped body. In such cases, only the outer edge zone of the molded body is used for the reaction. The remaining molded body is then only the carrier of this edge zone. With an expensive catalytic active composition, this is of course economically prohibitive. For this reason, you will switch to a supported or shell catalyst in the form of a shaped body in such a case. This contains an inert core and an outer shell made of catalytic active material.

Such catalysts are also produced with zeolites as active components. JP 07,241,471 describes the support of zeolite powder which is suspended in water and organic emulsifiers with an inorganic binder and then applied to the support by wash-coating. These catalysts are designed for exhaust gas purification. A similar procedure is followed by JP 07,155,613, according to which zeolites and silica sol are suspended in water and applied to a cordierite monolith carrier as a wash-coat suspension. JP 02,111,438 also describes the application of zeolites to monolith supports, aluminum sol being used as the binder. This catalytic converter is also used for exhaust gas purification. No. 4,692,423 describes the support of porous supports with zeolites by first adding cyclic oxides, which are unstable to polymerization, to the zeolite, coating the surface of the porous support with this suspension and then stripping off the solvent. No. 4,283,583 describes catalysts in which zeolite has been supported on spherical supports (diameter 0.5-10 mm).

Adhesion of the active component to the carrier is important for gas phase processes such as exhaust gas purification, but the forces that act on the supported layer in a gas phase process are much less abrasive than, for example, in a liquid phase process. This places far higher demands on the adhesion of the supported layer. In particular, the constant presence of liquid or solvent can lead to the destabilization of the anchoring of the active composition on the inert carrier. An application for a liquid phase process is described in JP 08,103,659. Here, titanium silicalite is applied to balls with a diameter of 0.2 - 20 mm. For this purpose, titanium silicalite is suspended in an aqueous solution of polyvinyl alcohol and sprayed onto the ball. The ready-to-use catalyst is then generated by calcining the sprayed ball and used in the epoxidation of propylene with hydrogen peroxide. The catalyst produced in this way still shows a clear abrasion of the active component. US Pat. No. 5,523,426 describes the possibility of epoxidizing propylene over titanium silicalite catalysts, in which the titanium silicalite can be applied, inter alia, to inert supports. No further explanation of the application process is given.

From the state of the art presented there arises the problem that in the case of the catalysts used hitherto the adhesion of the active component is generally not sufficient to be able to use them as wear-resistant supported catalysts. Furthermore, a restriction to spherical support bodies is often not sensible from a fluid dynamic point of view.

The invention was therefore based on the object of developing a process which makes it possible to apply zeolite and, in particular, titanium silicalite to any shaped, preferably non-monolithic, supports so that they can be used as catalysts in chemical processes, in particular in liquid phase processes, and the provision of such a catalyst per se.

Surprisingly, it has now been found that by applying a mixture comprising at least one porous oxidic material and at least one metal acid ester or a hydrolyzate thereof or a combination of metal acid ester and hydrolyzate on an inert carrier, a shaped body can be obtained which can be used without problems in liquid phase processes.

Accordingly, the present invention relates to moldings comprising an inert carrier and applied thereon at least one porous oxidic material, obtainable by applying a mixture comprising at least one porous oxidic material and at least one metal acid ester or a hydrolyzate thereof or a combination of metal acid ester and Hydrolyzate thereof on the inert carrier, and a method for producing such a shaped body, wherein a mixture containing at least one porous oxidic material and at least one metal acid ester or a hydrolyzate thereof or a combination of metal acid ester and hydrolyzate thereof is applied to an inert carrier.

The inert carriers which can be used according to the invention can consist of oxides, carbides, nitrides or other inorganic or organic materials, provided they do not show any decomposition, melting or other instabilities at the temperatures required in the production process.

The term "inert" used according to the invention means that the materials used as supports have no or at most negligible catalytic activity.

Metal oxides or mixed oxides of metals of III. to VIII. subgroup and III. to V. Main group of the periodic table, as well as a combination of two or more thereof, in particular silicon dioxide, aluminum oxide, titanium dioxide, zirconium dioxide and mixed oxides thereof.

Inert metals or metal alloys such as steel, Kanthai, aluminum, etc. can also be used as materials for the inert carrier.

The inert carrier preferably has an alkali metal or alkaline earth metal content of <1,000 ppm, preferably <100 ppm and in particular <10 ppm. The low alkali metal or alkaline earth metal contents of the support are particularly important when the catalyst according to the invention is used for epoxidation, in particular with a titanium silicalite as the porous oxidic material. The external shape of the inert support or molded body is not critical and can be chosen freely depending on the fluid dynamic conditions in the reactor specified for the reaction. The inert carrier or molded body can be in the form of strands, such as. B. round strands, star-shaped strands, hollow strands and cylinders, grit, tablets, ring tablets, a spherical, non-spherical or spherical granules, as monolith, in the form of a band-shaped or hole-forming structure, for example in the form of a network or fabric, in pyramid shape or as a wagon wheel profile.

The carrier or the shaped body is preferably present in the form of a non-spherical granulate, a strand, a grit, a tablet, a band-shaped structure or a structure having holes.

It is also possible to apply the porous oxidic material directly to the reactor wall. This is even conducive to heat dissipation in exothermic reactions.

There are no particular restrictions with regard to the porous oxidic materials which can be used to produce the shaped body according to the invention, as long as it is possible to produce a shaped body as described here starting from these materials and these materials have the necessary catalytic activity.

The porous oxidic material is preferably a zeolite, more preferably a zeolite containing titanium, zirconium, chromium, niobium, iron or vanadium and in particular a titanium silicalite.

Zeolites are known to be crystalline allumosilicates with ordered channel and cage structures that have micropores. The term "micropores", as used in the context of the present invention corresponds to the definition in "Pure Appl. Chem." 45, p. 71 ff., In particular p. 79 (1976), and designates pores with a pore diameter of less than 2 nm. The network of such zeolites is composed of SiO ₄ and AlO ₄ tetrahedra which are connected via common oxygen bridges. An overview of the known structures can be found, for example, by WM Meier and DH Olson in "Atlas of Zeolite Structure Types", Elsevier, 4th edition, London 1996.

Furthermore, there are zeolites which do not contain aluminum and in which titanium (Ti) is partly present in the silicate lattice instead of Si (IV). The titanium zeolites, in particular those with a crystal structure of the MFI type, and possibilities for their preparation are described, for example in EP-A 0 311 983 or EP-A 0 405 978. In addition to silicon and titanium, such materials can also contain additional elements such as Contain aluminum, zirconium, tin, iron, cobalt, nickel, gallium, boron or small amounts of fluorine.

In the zeolites described, the titanium thereof can be partially or completely replaced by vanadium, zirconium, chromium, niobium or iron. The molar ratio of titanium and / or vanadium, zirconium, chromium, niobium or iron to the sum of silicon and titanium and / or vanadium, zirconium, chromium, niobium or iron is generally in the range from 0.001: 1 to 0.1: 1.

Titanium zeolites with an MFI structure are known for being able to be identified by a certain pattern in the determination of their X-ray diffraction recordings and also by means of a framework vibration band in the infrared region (IR) at about 960 cm ^"1 and are thus different from alkali metal titanates or crystalline and amorphous Distinguish TiO ₂ phases. Usually, the titanium, zirconium, chromium, niobium, iron and vanadium zeolites mentioned are prepared by adding an aqueous mixture of an SiO ₂ source, a titanium, zirconium, chromium, niobium, iron or . Vanadium source, such as titanium dioxide or a corresponding vanadium oxide, zirconium alcoholate, chromium oxide, niobium oxide or iron oxide and a nitrogen-containing organic base as a template ("Schab ion compound"), such as tetrapropylammonium hydroxide, optionally with the addition of basic compounds, in one Pressure vessel under elevated temperature in the period of several hours to a few days, creating a crystalline product. This is filtered off, washed, dried and baked at elevated temperature to remove the organic nitrogen base. In the powder obtained in this way, the titanium or the zirconium, chromium, niobium, iron and / or vanadium is present at least partially within the zeolite structure in varying proportions with 4-, 5- or 6-fold coordination. To improve the catalytic behavior, a repeated washing treatment with sulfuric acid hydrogen peroxide solution can follow, after which the titanium or zirconium, chromium, niobium, iron, vanadium zeolite powder must be dried and fired again; this can be followed by treatment with alkali metal compounds in order to convert the zeolite from the H form to the cation form. The titanium or zirconium, chromium, niobium, iron, vanadium zeolite powder thus produced is then processed into a shaped body as described below.

Preferred zeolites are titanium, zirconium, chromium, niobium or vanadium zeolites, more preferably those with a pentasil zeolite structure, in particular the types with X-ray assignment to BEA, MOR, TON, MTW, FER, MFI -, MEL, CHA, ERI, RHO, GIS, BOG, NON, EMT, HEU, KFI, FAU, DDR, MTT, LTL, MAZ, GME, NES, OFF, SGT, EUO, MFS, MCM-22 or MFI / MEL mixed structure. Zeolite he of this type are described, for example, in the Meier and Olson reference cited above. Titanium-containing zeolites with the structure of UTD-1, CIT-1 or CIT-5 are also conceivable for the present invention. Such zeolites are described, inter alia, in US Pat. No. 5,430,000 and WO 94/29408, the content of which in this regard is incorporated in its entirety in the present application by reference.

There are also no particular restrictions with regard to the pore structure of the moldings according to the invention, i.e. The shaped body according to the invention can have micropores, mesopores, macropores, micropores and mesopores, micropore and macropores or micropores, mesopores and macropores, the definition of the terms “mesopores” and “macropores” likewise corresponding to those in the literature mentioned above Pure appl. Chem. Corresponds and designates pores with a diameter of> 2 nm to 50 nm or> 50 nm.

Furthermore, the shaped body according to the invention can be a material based on a mesoporous silicon-containing oxide and a silicon-containing xerogel.

Silicon-containing mesoporous oxides which also contain Ti, V, Zr, Sn, Cr, Nb or Fe, in particular Ti, V, Zr, Cr, Nb or a mixture of two or more thereof, are particularly preferred.

In order to obtain a shaped body with the desired abrasion resistance, the porous oxidic material described in detail above is always mixed with at least one metal acid ester or a hydrolyzate thereof or a combination of at least one metal acid ester and a hydrolyzate thereof (hereinafter often referred to as "metal acid ester (hydrolyzate)" referred to) applied to the inert support. acid esters can from III. and IV. main and III. to VI. Subgroup of the periodic table. Furthermore, their partial hydrolyzates can be used.

These include, in particular, orthosilicic acid esters, alkoxysilanes, tetraalkoxytitanates, trialkoxyaluminants, trialkoxyniobates, tetraalkoxyzirconates or a mixture of two or more thereof. However, tetraalkoxysilanes are particularly preferably used as metal acid esters in the context of the present invention. Tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetraisopropoxysilane and tetrabu-toxysilane, the analogous tetraalkoxytitanium and zirconium compounds as well as trimethoxy, triethoxy, tripropoxy, triisopropoxy or tri-ethoxysiloxysiloxysiloxysiloxysiloxysiloxysilane are particularly preferred.

The content of metal oxide according to the invention from the metal acid ester or the hydrolyzate thereof is preferably up to approximately 80% by weight, more preferably approximately 1 to approximately 50% by weight and in particular approximately 3 to approximately 30% by weight, based on the amount porous oxide.

The content of the mixture applied is generally about 1 to about 80% by weight, preferably about 1 to about 50% by weight and in particular about 3 to about 30% by weight, based in each case on the total amount of mixture and inert carrier .

As can be seen from the above, combinations of two or more of the above-mentioned binders can of course also be used. There are no particular restrictions on the application of the mixture to the inert carrier. The application can take place, for example, by soaking, spraying or trickling. Some preferred application methods are explained in more detail below.

To apply the at least one porous oxidic material, this is suspended and applied in the form of a powder or granulate in a liquid, or the porous oxidic material in powder or granular form and the liquid required for the adhesion of the porous oxidic material to the inert carrier can be metered simultaneously. The oxidic material to be applied is preferably suspended in the liquid and sprayed onto the carrier.

In one embodiment, the metallic acid ester (hydrolyzate) used according to the invention is mixed with the powdery or granular porous oxidic material. The mixture obtained is then allowed to trickle onto the inert carrier, which is simultaneously sprayed with an adhesive liquid. In this case, the hydrolysates of the metal acid esters are preferably used.

In another embodiment of the invention, the metal acid ester (hydrolyzate) is mixed with the adhesive liquid, and then this mixture together with the powdery or granular porous oxidic material is simultaneously applied to the inert carrier. Another preferred embodiment consists in suspending the metal acid ester (hydrolyzate) together with the porous oxidic material in the adhesion-promoting liquid and spraying the suspension onto the inert carrier. The alcohol used in the above mixture preferably corresponds to the alcohol component of the metal acid ester used or the hydrolyzate thereof, but it is also not critical to use a different alcohol.

A particularly rapid adhesion of the mixture can be achieved if the inert carrier is mixed with acidic substances, e.g. organic or inorganic acids such as e.g. Nitric acid, sulfuric acid, hydrochloric acid, acetic acid, oxalic acid or phosphoric acid.

The mixture to be applied to the inert carrier can contain further additives, e.g. contain organic viscosity-increasing substances and other additives, as defined below.

Water, various organic liquid classes such as e.g. Alcohols, diols, polyols, ketones, acids, amines, hydrocarbons and mixtures of two or more of these are possible. When using these liquids to suspend the porous oxidic material, liquids are preferably chosen which are vaporized at the spraying temperatures of approximately 30 to approximately 200 ° C., preferably approximately 50 to approximately 150 ° C. and in particular approximately 60 to approximately 120 ° C. can. If these liquids are added at the same time as adhesion promoters separately from the porous oxidic material, one will choose a liquid that boils significantly higher than at the specified temperatures.

In a preferred embodiment, the porous oxidic material is in

Alcohols such as B. methanol, ethanol, propanol, isopropanol and n-, iso-, tert-butanol and mixtures of two or more thereof, suspended. A mixture of an alcohol, preferably one, is further preferred alcohol mentioned above, used with water. The alcohol content of such a mixture is generally about 1 to about 80% by weight, preferably about 5 to about 70% by weight and in particular about 10 to about 60% by weight, based in each case on the total weight of the mixture from alcohol and water.

High-boiling liquids are to be understood as those with a boiling point at atmospheric pressure of more than 150 ° C. Propanediol, glycerol, ethanediol, polyether, polyester, dipropylene glycol or mixtures of two or more thereof can preferably be used as high-boiling liquids.

All suitable substances known from the prior art can also be used as the organic viscosity-increasing substance. These are preferably organic, in particular hydrophilic polymers, such as e.g. Cellulose, starch, polyacrylates, polymethacrylates, polyvinyl alcohol, polyvinyl pyrrolidone, polyisobutene, polytetrahydrofuran. These substances primarily promote the adhesion of the porous oxidic material to the carrier in the uncalcined state.

Amines or amine-like compounds such as e.g. Tetraalkylammonium compounds or amino alcohols, and carbonate-containing substances, such as e.g. Calcium carbonate can be added. Such further additives are described in EP-A 0 389 041, EP-A 0 200 260 and in WO 95/19222, which in this respect are fully incorporated into the context of the present application by reference.

After the mixture containing the porous oxidic material has been applied to the inert support, the shaped body thus obtained can be subjected to a calcination step. This calcination step can are eliminated if the shaped body is used as a catalyst in a reaction which is carried out at high temperatures and in the presence of oxygen. In this case, the calcination takes place in situ in the reactor.

This is particularly the case if the mixture of porous oxidic material and the metal acid ester (hydrolyzate) according to the invention is applied directly to the reactor wall and a reaction is subsequently carried out at high temperature.

Otherwise, the moldings are subjected to calcination. This achieves the hardness and abrasion resistance desired for the molded body. In general, the calcination is carried out at temperatures of approximately 200 ° C. to 1000 ° C., preferably 250 ° C. to 900 ° C. and particularly preferably approximately 300 ° C. to approximately 800 ° C., preferably in the presence of an oxygen-containing gas.

The moldings are preferably dried before the calcination, temperatures of approximately 50 to approximately 200 ° C., preferably approximately 80 to approximately 150 ° C. being used for this.

The moldings according to the invention or produced according to the invention have very good catalytic activity and excellent mechanical abrasion resistance, which make them suitable for use in liquid phase reactions.

The moldings according to the invention contain practically no fine-grained fractions than those with approximately 0.1 mm minimum particle diameter. The molded articles according to the invention or produced by the process according to the invention contain a porous oxidic material - compared to corresponding molded articles of the prior art - have improved mechanical stability while maintaining activity and selectivity.

The moldings according to the invention or produced according to the invention can be used for the catalytic conversion of organic molecules. Examples of such reactions are oxidations, the epoxidation of olefins such as the production of propylene oxide from propylene and H ₂ O ₂ , the hydroxylation of aromatics such as phenol from benzene and H ₂ O ₂ and hydroquinone from phenol and H ₂ O ₂ , the conversion of alkanes to alcohols, aldehydes and acids, isomerization reactions, such as, for example, the conversion of epoxides to aldehydes, and further reactions described in the literature with moldings of this type, in particular zeolite catalysts, as described, for example, in W. Hölderich, "Zeolites: Catalysts for the Synthesis of Organic Compounds", Elsevier, Stud. Surf. Be. Catal. , 49, Amsterdam (1989), pp. 69 to 93, and in particular for possible oxidation reactions by B. Notari in Stud. Surf. Be. Catal., 37 (1987), pp. 413 to 425.

The moldings discussed in detail above are particularly suitable for the epoxidation of olefins, preferably those having 2 to 8 carbon atoms, more preferably ethylene, propylene or butene, and in particular propene to give the corresponding olefin oxides. Accordingly, the present invention relates in particular to the use of the shaped body described here for the production of propylene oxide starting from propylene and hydrogen peroxide, as described, for example, in EP-A 0 100 119. EXAMPLES

Production Example 1

910 g of tetraethyl orthosilicate were placed in a four-necked flask (4 1 contents) and 15 g of tetraisopropyl orthotitanate were added from a dropping funnel over the course of 30 minutes with stirring (250 rpm, blade stirrer). A colorless, clear mixture was formed. Then 1600 g of a 20% strength by weight tetrapropylammonium hydroxide solution (alkali content <10 ppm) were added and the mixture was stirred for another hour. The alcohol mixture formed from the hydrolysis (approx. 900 g) was distilled off at 90 to 100 ° C. It was filled with 3 l of water and the now slightly opaque sol was placed in a 5 l stainless steel stirred autoclave.

The sealed autoclave (anchor stirrer, 200 rpm) was brought to a reaction temperature of 175 ° C. at a heating rate of 3 ° C./min. The reaction was complete after 92 hours. The cooled reaction mixture (white suspension) was centrifuged off and washed neutral with water several times. The solid obtained was dried at 110 ° C. in the course of 24 hours (weight: 298 g).

Subsequently, the template remaining in the zeolite was burned off in air at 550 ° C. in 5 hours. (Calcination loss: 14% by weight).

According to wet chemical analysis, the pure white product had a Ti content of 1.3% by weight and a residual alkali content below 100 ppm. The yield on SiO _{2 used} was 97%. The crystallites had a size of 0.05 to 0.25 μm and the product showed a typical band at approx. 960 cm ^"1 in the IR spectrum. Comparative Example 1

120 g of titanium silicalite powder, synthesized according to Preparation Example 1, were mixed with 48 g of tetramethoxysilane in a kneader for 2 hours. 6 g of Walocel (methyl cellulose) were then added. 77 ml of a water-methanol mixture in which the methanol content was 25% by weight were then added to the paste. This mass was compressed in the kneader for a further 2 h and then shaped into 1 mm strands in an extruder. The strands obtained were dried at 120 ° C for 16 hours and then calcined at 500 ° C for 5 hours. The catalyst VI thus obtained was examined in epoxidation tests for its epoxidation properties.

Comparative Example 2

120 g of titanium silicalite powder, synthesized according to Preparation Example 1, were mixed with 48 g of tetramethoxysilane in a kneader for 2 hours. 6 g of Walocel (methyl cellulose) were then added. 77 ml of a water-methanol mixture in which the methanol content was 25% by weight were then added to the paste. This mass was compacted in a kneader for a further 2 hours and then shaped into 3 mm strands in an extruder. The strands obtained were dried at 120 ° C for 16 hours and then calcined at 500 ° C for 5 hours. The catalyst V2 obtained in this way was examined in epoxidation tests for its epoxidation properties.

Production Example 2

2500 g of Aerosil 200 (Degussa) were compacted with 150 g of ammonia solution (30%), 100 g of potato starch and 3000 g of water in a kneader formed into 2 mm strands in an extrusion press. The strands thus obtained were dried at 110 ° C. and calcined at 500 ° C. for 16 hours. The strands thus obtained had an alkali content of 40 ppm. For the following examples, half of the strands were processed into 1-1.6 mm chips.

example 1

10 g of titanium silicalite powder from Preparation Example 1 (particle sizes <0.1 mm) were suspended in 100 g of methanol and 4 g of tetramethoxysilane. 100 g of Aerosil grit from preparation example 2 were placed in a heated spray plate. The suspension of the titanium silicalite in methanol / tetramethoxysilane was slowly sprayed on while rotating the spray plate evenly. The grit thus obtained was dried at 120 ° C., sieved and calcined at 500 ° C. for 5 hours. When sieving after drying, about 7 g of TS-1 powder were recovered. After calcination, abrasion-resistant moldings were obtained which are suitable for liquid phase reactions. The titanium silicalite content of the shaped body was 2% by weight according to the atomic emission spectroscopy analysis. The epoxidation properties of the catalyst A obtained in this way were investigated in epoxidation experiments.

Example 2

10 g of titanium silicalite powder from preparation example 1 (particle sizes <0.1 mm) were suspended in 100 g of methanol and 4 g of tetramethoxysilane. 100 g of Aerosil grit from preparation example 2 were impregnated with acetic acid and placed in a heated spray plate. The suspension of the titanium silicalite in methanol / tetrahedral was methoxysilane slowly sprayed on. The grit thus obtained was dried at 120 ° C., briefly sieved and calcined at 500 ° C. for 5 hours. When sieving after drying, about 2 g of TS-1 powder were recovered. After calcination, abrasion-resistant molded articles were obtained which are suitable for liquid-phase reactions. The titanium silicalite content of the shaped body was 5% by weight, according to the atomic emission spectroscopy analysis. By soaking the moldings with acetic acid, better adhesion of the TS-1 was achieved when sprayed on. The epoxidation properties of the catalyst B obtained in this way were investigated in epoxidation experiments.

Example 3

20 g of titanium silicalite powder from preparation example 1 (particle sizes <0.1 mm) were suspended in 300 g of methanol and 8 g of tetramethoxysilane. 100 g of Aerosil strands from Preparation Example 2 were impregnated with acetic acid and placed in a heated spray plate. The suspension of the titanium silicalite in methanol / tetramethoxysilane was slowly sprayed on while rotating the spray plate evenly. The strands thus obtained were dried at 120 ° C., briefly sieved and calcined at 500 ° C. for 5 hours. When sieving after drying, about 3 g of TS-1 powder were recovered. After calcination, abrasion-resistant molded articles were obtained which are suitable for liquid-phase reactions. The titanium silicalite content of the shaped body was 8.5% by weight according to the atomic emission spectroscopy analysis. The epoxidation properties of the catalyst C obtained in this way were investigated in epoxidation experiments. Comparative example 3

10 g of titanium silicalite powder from preparation example 1 (particle sizes <0.1 mm) were suspended in 100 g of methanol and 4 g of tetramethoxysilane. 100 g of silicon dioxide balls (Siliperl AF-125, Engelhardt) were placed in a heated spray plate. The suspension of the titanium silicalite in methanol / tetramethoxysilane was slowly sprayed on while rotating the spray plate evenly. The spheres thus obtained were dried at 120 ° C., sieved briefly and calcined at 500 ° C. for 5 hours. When sieving after drying, about 7 g of TS-1 powder were recovered. According to the atomic emission spectroscopy analysis, the titanium silicalite content of the shaped body was 2% by weight and the alkali content was 400 ppm. The epoxidation properties of the catalyst V3 obtained in this way were investigated in epoxidation experiments.

Examples 4 to 9

The quantities of catalysts A to C and VI to V3 given in Table 1 were installed in a steel autoclave with a basket insert and a gas stirrer. The autoclave was filled with 100 g of methanol, closed and checked for leaks. The autoclave was then heated to 40 ° C. and 11 g of liquid propene were metered into the autoclave. 9.0 g of an aqueous hydrogen peroxide solution (content of hydrogen peroxide in the solution 30% by weight) were then pumped into the autoclave using an HPLC pump, and the hydrogen peroxide residues in the feed lines were then rinsed in the autoclave with 16 ml of methanol. The initial hydrogen peroxide content of the reaction solution was 2.5% by weight. After a reaction time of 2 hours, the autoclave was cooled and let down. The liquid discharge was examined cerimetrically for hydrogen peroxide. The analysis and the propylene oxide (PO) content was determined by gas chromatography.

The PO and hydrogen peroxide contents can be found in Table 1.

Catalyst VI (TS-1, 1 mm strands) is significantly more active than Catalyst V2 (TS-1, 3 mm strands). This suggests poor use of the TS-1 strand with a diameter of 3 mm (V2). The supported catalysts A to C achieved a higher PO yield despite the lower amount of TS-1 used. Catalyst V3 shows almost no epoxidation activity due to the high alkali content of 400 ppm.

No abrasion was found in the supported catalysts (no TS-1 in the discharge) despite the strong mechanical load in the stirred steel autoclave.

Table 1

Epoxidation of propene to propene oxide in batch operation in an autoclave

99/29426

^■ - 22

Examples 10 to 13

A reactor cascade of two reactors with a reaction volume of 98 ml each and a downstream tubular reactor with a volume of 13 ml, filled with the amount of catalysts VI, V2, A and B given in Table 2, caused flows of 27.5 g / h hydrogen peroxide (20 % By weight), 65 g / h of methanol and 14 g / h of propene at 40 ° C. reaction temperature and 20 bar reaction pressure. After leaving the tubular reactor, the reaction mixture was let down in a Sambay evaporator against atmospheric pressure. The separated low boilers were analyzed on-line in a gas chromatograph. The liquid reaction product was collected, weighed and also analyzed by gas chromatography. During the running time of 30 h, the hydrogen peroxide conversion dropped from originally 96% to the value given in Table 2. The selectivity of PO based on hydrogen peroxide was always over 95%.

Table 2

Continuous epoxidation of propene with hydrogen peroxide to propylene oxide

In this mode of operation, too, supported TS-1 catalysts are significantly more reactive in relation to the amount of TS-1 used than the catalysts used in the form of full contact (strand).

In the tests, no abrasion could be found on the catalysts (TS-1 in the discharge) despite the strong mechanical stress in the stirred reactors.

Claims

claims

1. Shaped body comprising an inert carrier and applied thereon at least one porous oxidic material, obtainable by applying a mixture containing at least one porous oxidic material and at least one metallic acid ester or a hydrolyzate thereof or a combination of metallic acid ester and hydrolyzate thereof on the inert carrier.

2. Shaped body according to claim 1 in the form of a non-spherical granulate, a strand, a grit, a tablet, a band-shaped structure or a structure having holes.

3. Shaped body according to claim 1 or 2, wherein the porous oxidic material is a zeolite, preferably a titanium, zirconium, chromium, niobium, iron or vanadium-containing zeolite, a mesoporous silicon-containing oxide or a silicon-containing Xerogel, and especially one

Is titanium silicalite.

4. Shaped body according to one of claims 1 to 3, wherein the molded body has micropores, mesopores, micro and mesopores, micro and macro pores or micro, meso and macro pores.

5. Molded body according to one of claims 1 to 4, wherein the metal acid ester is selected from the group consisting of an orthosilicic acid ester, an alkoxysilane, a tetraalkoxy titanate, one Trialkoxyaluminate, a tetraalkoxy zirconate and a mixture of two or more thereof.

6. A process for the production of a molded article according to one of claims 1 to 5, wherein a mixture containing at least one porous oxidic material and at least one metal acid ester or

Hydrolyzate thereof or a combination of metal acid ester and

Hydrolyzate thereof is applied to an inert carrier.

7. The method of claim 6, wherein the mixture is applied by a spray process.

8. The method according to claim 6 or 7, wherein the mixture additionally contains at least one alcohol or a mixture of at least one alcohol and water.

9. Use of a molded article according to one of claims 1 to 5 or a molded article produced by a process according to one of claims 6 to 8 or a mixture of two or more thereof for the epoxidation of organic compounds with at least one C-

C double bond, for the hydroxylation of aromatic organic compounds, or for the conversion of alkanes to alcohols, ketones, aldehydes and acids.

10. Use of a molded article according to one of claims 1 to 5 or a molded article produced by a process according to one of claims 6 to 8 for the epoxidation of an olefin, preferably for the production of propylene oxide starting from propylene and hydrogen peroxide.