DE102010055680A1 - Composition, useful in e.g. extrudate, comprises an aluminosilicate zeolite and a titano-(silico)-alumino-phosphate, where both aluminosilicate zeolite and titano-(silico)-alumino-phosphate comprise a transition metal e.g. iron or copper - Google Patents

Abstract

Composition comprises an aluminosilicate zeolite and a titano-(silico)-alumino-phosphate, where both the aluminosilicate zeolite and the titano-(silico)-alumino-phosphate comprise at least one transition metal, which is iron, copper, manganese, cobalt, chromium, vanadium or molybdenum. An independent claim is included for the selective catalytic conversion of nitrogen containing compound in exhaust gas flow, where the composition is used the catalyst.

Description

The present invention relates to a composition comprising an aluminosilicate zeolite and a titano (silico) -alumino-phosphate, wherein the alumino-silicate zeolite and the titano (silico) -alumino-phosphate are each at least one transition metal selected from Group consisting of Fe, Cu, Mn, Co, Cr, V and Mo included. Furthermore, the present invention relates to a washcoat, an extrudate, a bulk extrudate or a carrier body containing the composition according to the invention. Furthermore, the composition according to the invention is used in a process for the selective catalytic conversion of nitrogen-containing compounds. The reaction involves either the selective catalytic reduction (SCR) of nitrogen oxides, or the selective catalytic oxidation (SCO) of nitrogen-hydrogen compounds and nitrogen-containing organic compounds, preferably in exhaust gas streams of engine and non-engine combustion processes and industrial applications. In a further embodiment, the present invention relates to the use of the composition for producing an exhaust-gas purification catalyst and to an exhaust-gas purification catalyst comprising the composition according to the invention.

For the purposes of this invention, selective catalytic reduction of nitrogen oxides is understood as meaning their reaction with reducing agents such as hydrocarbons, CO, ammonia, other nitrogen-hydrogen compounds and nitrogen-containing organic compounds to nitrogen, water (and carbon dioxide).

For the purposes of this invention, selective catalytic oxidation means the reaction of ammonia, other nitrogen-hydrogen compounds and nitrogen-containing organic compounds into nitrogen, water (and carbon dioxide).

In engine combustion processes, such as in diesel engines and gasoline-injected engines and in non-engine combustion processes, but also in certain industrial applications, such. As the production of nitric acid so-called DeNOx catalysts are required, which reduce nitrogen oxides in the exhaust stream by selective catalytic reduction. For this purpose, molecular sieves are often required, which provide a high surface area and in which the catalytically active components can be incorporated surface active. Zeolites or zeolite-like materials which are doped with an active metal, which constitutes the essential catalytically active component, are generally used as molecular sieves in the prior art.

Alumo-silicates (zeolites), alumino-phosphates (ALPOs) and silico-aluminophosphates (SAPOs) have long been used as active components for refinery, petrochemical and chemical catalysts as well as for the purification of exhaust gases both in stationary and in the state of the art known in mobile applications. These groups are often only listed under the collective name Zeolithe.

Zeolites in the context of the present invention are crystalline substances with a spatial network structure which consist of SiO ₄ and AlO ₄ tetrahedra which are linked by common oxygen atoms to form a regular three-dimensional network. Zeolites contain cavities that are characteristic of each type of structure. The zeolites are classified into different structures according to their topology. The crystal framework contains open cavities in the form of channels and cages that are normally filled with water molecules and additional framework cations that can be exchanged. Each aluminum atom generates a negative excess charge which is compensated by cations. The interior of the pore system represents the catalytically active surface. The more aluminum a zeolite contains, the denser the negative charge in its lattice and the more polar its internal surface. The pore size and structure are determined by the Si / Al ratio, which accounts for most of the catalytic character of a zeolite, besides the parameters of manufacture, ie, use, or type of templates, pH, pressure, temperature, presence of seed crystals. The negative charge caused by the aluminum atoms is compensated by the incorporation of cations into the pores of the zeolite material.

Pure, non-ion exchanged zeolites typically contain H ⁺ ions as counterions within their pore system that induce Brönsted acid properties, but also against other cations, e.g. B. metal cations can be replaced.

For catalytic applications, these materials are often modified with other components. In off-gas catalysis, transition metals such as precious metals or iron, copper, cobalt, etc., are usually modified. In this case, the transition metals are present as cations or as cationic metal complexes as counterions in the interior of the pore system.

These then present as a powder materials are then either deformed into extrudates, deformed with the aid of oxidic and organic binders to Vollextrudaten / honeycomb catalysts or applied via the intermediate stage of a washcoat on ceramic or metallic honeycomb.

In the prior art, iron-exchanged zeolites are preferably used in the reduction of nitrogen oxides or nitrogen-hydrogen compounds in exhaust gases. In particular, structures of the MFI or BEA type, which are active especially at high temperatures, have proven to be advantageous. At low temperatures, however, the activity is reduced.

Transition metal-exchanged, especially copper-exchanged, zeolites have been found to be suitable catalysts in the reduction of nitrogen oxides at low temperatures. At high temperatures, however, the reaction is not complete and it may be observed an increased formation of nitrous oxide and NO _x under certain circumstances.

Silico-alumino-phosphates (SAPOs) are generally understood to mean molecular sieves obtained from aluminophosphates (general formula (AlPO ₄ -n)) by isomorphous exchange of phosphorus with silicon and having the general formula (Si _x Al _y P _z ) O ₂ (anhydrous) correspond ( EP 0 585 683 ), where x + y + z = 1 and the SAPO framework has negative charges, the number of which depends on how many phosphorus atoms have been replaced by silicon atoms, or how many of them are dependent on the excess of aluminum atoms to the phosphorus atoms.

Structures of this group are classified according to the International Union of Pure and Applied Chemistry (IUPAC) according to the Structure Commission of the International Zeolite Association because of their pore size. They crystallize in more than 200 different compounds in two dozen different structures. They are classified based on their pore sizes.

SAPOs are typically available by hydrothermal synthesis, starting from reactive alumino-phosphate gels, or the individual Al, Si, P components. The crystallization of the resulting silico-aluminophosphates (SAPOs) is achieved by adding structure-directing templates , Crystallization seeds or elements ( EP 103 117 A1 . US 4,440,871 . US 7,316,727 ).

The framework structure of the SAPOs is built up of regular, three-dimensional spatial networks with characteristic pores and channels, which can be linked together in one, two or three dimensions. The structures mentioned above are formed by corner-sharing tetrahedral building blocks (AlO ₄ , SiO ₄ , PO ₄ ), each consisting of four times oxygen-coordinated aluminum, silicon and phosphorus. The tetrahedra are called primary building blocks, the linkage of which leads to the formation of secondary building units. Silico-aluminophosphates (SAPOs) crystallize, among others, in the known CHA structure (chabazite), classified according to IUPAC due to their specific CHA unit.

In the aluminophosphates, charge neutrality prevails due to the balanced number of aluminum and phosphorus atoms. These systems thus have the disadvantage that they do not require any counterions in cavities for charge compensation. Thus, catalytically active metal ions can not be effectively incorporated into these cavities by ionic bonding. Therefore, these aluminophosphates are poorly suited as molecular sieves in catalysts for the removal of nitrogen oxides from the exhaust gas stream of internal combustion engines.

Through isomorphous exchange / replacement of phosphorus with silicon, silico-alumino-phosphates produce excess negative charges, which are compensated for by incorporation of additional cations into the pore and channel system. The degree of phosphorus-silicon substitution from alumino-phosphates thus determines the number of cations needed to balance, and thus the maximum possible loading of the compounds with positively charged cations, eg. For example, hydrogen or metal ions. By incorporating the cations, the acidic catalytic properties of the silico-aluminophosphates are determined, and can be used by targeted ion exchange in terms of their activity and selectivity as catalyst components. The so-called SAPO-34 with CHA structure and pore openings of about 3.5 Å is particularly preferred as the molecular sieve in catalysts. Silico-alumino-phosphates (SAPOs) are suitable as molecular sieves in particular in so-called SCR catalysts for the selective catalytic reduction of NO _x with hydrocarbons such. As propene or ammonia, since in the selective reduction of NO _x gases often a large hydrothermal stability is necessary because often meet exhaust gas streams with high water content at high temperatures on the catalyst. In the prior art, especially copper-exchanged SAPO-34 as a suitable catalyst for the reduction of nitrogen oxides at low temperature used. Even with SCO applications, exhaust gases with high water content are often to be cleaned off, so that the silico-aluminophosphates also have technical advantages here and are therefore of great economic interest. In the case of the abovementioned SAPOs, the surface does not decrease under reaction conditions (in comparison to zeolites) and the acidity hardly reduces. However, SAPOs have the disadvantage that they are thermally relatively unstable in the aqueous phase. So amorphizes z. B. SAPO-34 even at low temperatures - including in the preparation of the catalyst in aqueous phases.

It was therefore the object of the present invention to provide a catalytic composition for an exhaust gas purifying catalyst component and a method for reacting nitrogen-containing compounds in exhaust gas streams with which high conversions can be achieved at low and high temperatures, if possible without producing nitrous oxide.

The present invention provides for this purpose a (catalytic) composition comprising an aluminosilicate zeolite and a titano (silico) -alumino-phosphate, wherein the alumino-silicate zeolite and the titano (silico) -alumino-phosphate are each at least a transition metal selected from the group consisting of Fe, Cu, Mn, Co, Cr, V and Mo. It is particularly preferred that the alumino-silicate zeolite contains iron as the transition metal and the titano (silico) -alumino-phosphate as transition metal copper. It is particularly preferred that the alumino-silicate zeolite contains iron as the sole metal. Likewise, it is particularly preferred that the titano (silico) -alumino-phosphate contains copper as the sole metal. In a particularly preferred form of the alumino-silicate zeolite contains only iron and the titano (silico) -alumino-phosphate only copper as the transition metal. In other words, it is a particularly preferred variant of the present invention that the alumino-silicate zeolite in addition to iron and the titano (silico) -alumino-phosphate in addition to copper contains no further transition metals.

Like the abovementioned SAPOs, the titano- (silico) -alumino-phosphates in the context of the present invention are crystalline substances with a spatial network structure consisting of TiO ₄ / (SiO ₄ ) / AlO ₄ / PO ₄ tetrahedra and owing to common oxygen atoms linked to a regular three-dimensional network. All these tetrahedral units together form the so-called "framework". Further units that do not consist of the tetrahedral units of the backbone are called "extra frameworks".

The structures of titano- (silico) -alumino-phosphates contain cavities that are characteristic of each type of structure. Like the zeolites, this structural class represents molecular sieves. They are classified into different structures according to their topology (IUPAC). The crystal framework contains open cavities in the form of channels and cages that are normally wetted with water molecules and additional framework cations that can be exchanged. In the case of the so-called aluminophosphates, at least in the "framework" of the titano (silico) -alumino-phosphate, an aluminum atom is replaced by one phosphorus atom, so that the charges balance each other. If titanium atoms substitute the phosphorus atoms, the titanium atoms form an excess negative charge that is compensated by cations. The interior of the pore system represents the catalytically active surface. The less phosphorus in relation to aluminum contains a titano- (silico) -alumino-phosphate in the framework, the denser the negative charge in its lattice and the more polar is its inner surface. The pore size and structure is in addition to the parameters in the production, d. H. Use or type of template, pH, pressure, temperature, presence of seed crystals determined by the P / Al / Ti / (Si) ratio, which accounts for the largest part of the catalytic character of a titano-alumino-phosphate or titano (Silico ) Alumino-phosphate. The substitution of phosphorus atoms by titanium atoms with respect to the framework results in a deficit of positive charges, so that the molecular sieve is negatively charged overall. The negative charges are compensated by the incorporation of cations into the pores of the zeolite material. In addition to titanium atoms, as apparent from the above parenthetical optional presence of silicon, silicon atoms can also replace the phosphorus atoms. These then also cause negative charges, which must be compensated by cations.

The titano- (silico) -alumino-phosphates used according to the invention are distinguished, as in the prior art, mainly according to the geometry of the cavities formed by the rigid network of the TiO ₄ / AlO ₄ / (SiO ₄ ) / PO ₄ tetrahedra be formed. The entrances to the cavities are formed by 8, 10 or 12 ring atoms with respect to the metal atoms which form the entrance opening, the skilled person speaking here of narrow, medium and wide-pore structures. According to the invention, narrow-pore structures are preferred here. These titano- (silico) -alumino-phosphates may have a uniform structure structure, e.g. As a VFI or AET topology with linear channels show, but other topologies are conceivable in which join behind the pore openings larger cavities. According to the invention, preference is given to titano (silico) -aluminum Phosphates with openings of eight tetrahedral atoms, ie narrow-pored materials. These preferably have an opening diameter of about 3.1 to 5 Å, particularly preferably 3.4 to 3.6 Å.

By the term "molecular sieve" is meant natural and synthetic skeletal structures with cavities and channels, such as zeolites and related materials, which have high absorbance for gases, vapors, and solutes having particular molecular sizes.

It has surprisingly been found that titanium-containing (silico) -alumino-phosphates are particularly suitable as molecular sieves in exhaust gas purifying catalyst components, in particular SCR and SCO catalysts. The titano- (silico) -alumino-phosphates are excellently suitable as molecular sieves in SCR and SCO catalysts due to their high phase purity, their temperature stability, their high possible loading fraction with transition metal ions and their high ammonia storage capacity.

The titano- (silico) -alumino-phosphate used in the composition according to the invention preferably has an acidity of 1000-1500 μmol / g and particularly preferably an acidity of 1100-1400 μmol / g, which is determined by means of temperature-programmed desorption of ammonia. An acidity in this area is particularly important to store the predominantly acidic reducing agents in SCR applications, or the nitrogen-hydrogen compounds such as ammonia and nitrogen-containing organic compounds in SCO applications.

It is furthermore preferred for the titano- (silico) -alumino-phosphate in the composition according to the invention to have a BET surface area in the range from 200 to 1200 m ² / g, particularly preferably 400 to 850 m ² / g, even more preferably 500 up to 750 m ² / g. The BET surface area of the molecular sieve should not be too low, since then there is no sufficient contact of the nitrogen oxides with the catalytically active components and thus the reduction of the nitrogen oxides does not take place sufficiently. Too high a BET surface area has the disadvantage that due to the low density of the material, it is no longer sufficiently stable in temperature. The BET surface area is reduced by adsorption of nitrogen DIN 66132 certainly.

In the prior art, zeolites with MFI and BEA structures are predominantly not used with CHA structure zeolites. However, their thermal stability is very limited. For example, in a hydrothermal aging test (conditions: 10% by volume H ₂ O, 700 ° C., duration 24 hours) the surface area of a zeolite with BEA structure was 11% and that of a zeolite with MFI structure was 8 % decreases. In addition, both materials show significantly lower levels of acidity after the aging test, as determined by temperature programmed desorption of ammonia. The zeolite with the BEA structure loses 54% of its acidity and the zeolite with the MFI structure loses 77% of its acidity. In contrast, the inventive titanium-containing (silico) -alumino-phosphate TAPSO-34 loses only 19% of its acidity in the aging test. Because of its high hydrothermal stability, the titano- (silico) -alumino-phosphate used according to the invention is thus particularly suitable for use in the humid atmosphere at high temperatures, as prevail in certain engine and non-engine SCR and SCO applications.

Particularly suitable for the purposes of this invention, a titanium-containing (silico) -alumino-phosphate has proven with a CHA structure, which preferably has a structure with small pore openings of about 3.5 Å. These structures are particularly suitable for engine applications, since they have a high adsorption of unburned fuel in the starting phase of engines as a so-called cold start trap, which can be used after warming up the system as a reducing agent for the nitrogen oxides.

The titano-silico-aluminophosphates used in the composition according to the invention are preferably selected from TAPSO-5, TAPSO-8, TAPSO-11, TAPSO-16, TAPSO-17, TAPSO-18, TAPSO-20, TAPSO-31, TAPSO -34, TAPSO-35, TAPSO-36, TAPSO-37, TAPSO-40, TAPSO-41, TAPSO-42, TAPSO-44, TAPSO-47, TAPSO-56. Particularly preferred are TAPSO-5, TAPSO-11 or TAPSO-34, since they have a particularly high hydrothermal stability to water. TAPSO-5, TAPSO-11 and TAPSO-34 are also particularly suitable because of their good properties as a catalyst in various processes due to their microporous structure and because they are very well suited as an adsorbent due to their high adsorption capacity. In addition, they also show a low regeneration temperature, as they already give adsorbed water or adsorbed other small molecules reversibly at temperatures between 30 ° C and 90 ° C. According to the invention, the use of microporous titano-silico-aluminophosphates with CHA structure is particularly suitable. Most preferably, the molecular sieve used in the composition of the invention is a so-called TAPSO-34, as in the prior art, for example of the EP 161 488 and US 4,684,617 is known. The excellent hydrothermal stability of TAPSO-34 as well as the small pore openings predestine TAPSO-34 as a selective catalyst for the reduction of nitrogen oxides.

Due to the low pore opening of TAPSO-34 (3.8 Å x 3.8 Å), it is believed that the migration of the transition metal ions, especially copper ions, from the pore system during the preparation of the composition of the invention, especially the production of a washcoat according to the invention mentioned below, is severely handicapped. The strongly bound hydration shell of transition metal ions, in particular that of copper ions, is larger than the pore opening of the TAPSO-34 molecular sieve and therefore severely limits the mobility of the ions. For example, copper-containing zeolitic molecular sieves such as Cu-MFI or Cu-BEA have a pore system whose pore openings or channels are larger than the copper ions with their hydration shell. Thus, during the production of the washcoat, a migration and agglomeration of the copper ions occurs, which reduces their dispersion and thus the number of catalytically active centers. Further, when using conventional zeolites as molecular sieves, the copper ions may agglomerate with the further used transition metal ions, in particular iron ions, which may adversely affect both the high temperature selectivity and the low temperature activity of the catalyst by forming larger mixed crystals.

In the case of the (catalytic) composition according to the invention, obviously the small pore openings of the titano (silico) -alumino-phosphate, preferably TAPSO-34, prevent the penetration of iron ions with their strongly bound hydrated shell into the pore system and thus a mixing of the copper and iron ions , Due to the separation of the two active catalytic centers therefore no negative mutual influence of the components takes place.

The titano- (silico) -alumino-phosphate used in the composition according to the invention has negative charges due to the exchange of phosphorus atoms by titanium or silicon atoms, which are compensated by cations. In the synthesis of titano (silico) -alumino-phosphates, which for many years from the EP 161 488 is known, the molecular sieve preferably exists "in the protonated or in the Na ⁺ form. In the composition according to the invention, the titano- (silico) -alumino-phosphate is present in a modified form in which, as counter ions, copper ions or a cationic copper complex are present in the cavities for compensation of the negative charges. The cations present in the interior of the framework structure give the structure the catalytic properties. The ion exchange of H ⁺ or Na ⁺ by cations can be carried out both in liquid and in solid form, it also being possible for different cations to be introduced simultaneously or after each other in several exchange steps. In addition, gas phase exchange processes are known, but they are too expensive for technical processes. A disadvantage of the current state of the art is that during solid ion exchange, although a defined amount of metal ions can be brought into the titano (silico) -alumino-phosphate skeleton, but there is no homogeneous distribution of the metal ions. In the case of liquid ion exchange, by contrast, a homogeneous metal ion distribution in the titano- (silico) -alumino-phosphate can be achieved. In the case of small-pore molecular sieves, however, it is disadvantageous in the case of liquid aqueous ion exchange that the hydration shell of the metal ions is too large for the metal ions to be able to pass through the small pore openings and the exchange rate therewith to be very low. In addition to the methods mentioned, doping or modification with one or more metal cations can be carried out by aqueous impregnation or the incipient wetness method. These doping or modifying methods are known in the art. It is particularly preferred that the doping or modification be carried out by means of one or more metal compounds by aqueous ion exchange, wherein both metal salts and metal complexes are used as ion sources.

The molecular sieve modified with the cation preferably has the following formula: [(Ti _x Al _y Si _z P _q ) O ₂ ] ^-a [Mb ⁺ ] _{a / b} where the symbols and indices used have the following meanings: x + y + z + q = 1; 0.010 ≤ x ≤ 0.110; 0.400 ≦ y ≦ 0.550; 0 ≤ z ≤ 0.090; 0.350 ≤ q ≤ 0.450; a = y - q (with the proviso that y is preferably greater than q); M ^{b +} represents the cation with the charge b +, where b is an integer greater than or equal to 1, preferably 1, 2, 3 or 4, even more preferably 1, 2 or 3 and most preferably 1 or 2.

The number of negative charges a of the molecular sieve results from the excess number of aluminum atoms to the number of phosphorus atoms. Assuming that each of the Ti, Al, Si and P atoms has two oxygen atoms, these units would have the following charges: The unit TiO ₂ and the unit SiO ₂ are charge neutral, the unit AlO ₂ is due to the triviality of aluminum has a negative charge and the unit PO ₂ has a positive charge due to the pentavalence of phosphorus. It is particularly preferred according to the invention that the number of aluminum atoms is greater than the number of phosphorus atoms, so that the molecular sieve is negatively charged overall. This is expressed in the above formula by the subscript a, which represents the difference of the aluminum atoms present minus the phosphorus atoms. This is especially the case because positively charged PO ₂ ⁺ units are substituted by charge-neutral TiO ₂ or SiO ₂ units.

In addition to the aforementioned SiO ₂ , TiO ₂ , AlO ₂ ^- and PO ₂ ⁺ units, which form the framework of the molecular sieve and whose ratio determines the valence of the molecular sieve, the molecular sieve may also contain Al and P units, are to be regarded as such formally charge neutral, for example, because not O ^2- units occupying the coordination sites, but because other units, such as OH ^- or H ₂ O sit at this point, preferably, if this terminal or marginal in the structure available. This proportion of units of the molecular sieve is then called the so-called "extraframework" of the molecular sieve.

The molecular sieve used in the process of the present invention preferably has a (Si + Ti) / (Al + P) molar ratio of 0.01 to 0.5 to 1, more preferably 0.02 to 0.4 to 1, even more preferably 0 0.05 to 0.3 to 1, and most preferably 0.07 to 0.2 to 1.

It is also particularly preferred that the molecular sieve used in the process according to the invention contains Si as an essential element in addition to Ti. In particular, the silicon-containing titano-alumino-phosphate is characterized by its high hydrothermal stability.

The Si / Ti ratio is preferably in the range of 0 to 20, more preferably in the range of 0.5 to 10, even more preferably in the range of 1 to 8. The Al / P ratio with respect to all units of the molecular sieve, d. H. that of the framework and extra framework of the titano (silico) alumino-phosphate is preferably in the range of 0.5 to 1.5, more preferably in the range of 0.70 to 1.25. The Al / P ratio only with respect to the framework of the titano (silico) alumino-phosphate is preferably in the range of greater than 1 to 1.5, more preferably in the range of 1.05 to 1.25.

The transition metal, in particular copper, is present in the titano- (silico) -alumino-phosphate of the composition according to the invention preferably in a range from 1 to 10.0% by weight, more preferably in a range from 1 to 9% by weight. even more preferably in a range of from 2 to 8 weight percent, more preferably in a range of from 3 to 7 weight percent, even more preferably in a range of from 4 to 6 weight percent, and most preferably in Range of 5 and 5.5 wt .-%, based on the total mass of the titano (silico) -alumino-phosphate and the transition metal.

The alumino-silicate zeolite in the composition of the present invention preferably has an MFI or BEA type structure. The Si / Al ratio of the zeolites is preferably in the range from 10 to 50 and particularly preferably in the range from 12 to 30.

The transition metal, preferably iron, in the alumino-silicate zeolite of the composition of the invention is preferably present in a range of 0.1 to 10.0 weight percent, more preferably 0.5 to 7 weight percent, even more preferably From 1 to 5% by weight, and most preferably from 1.5 to 3% by weight, based on the total mass of the aluminosilicate zeolite and the transition metal.

In the composition of the present invention, the titano (silico) -alumino-phosphate is preferably in the range of 10 to 90% by weight, more preferably 30 to 60% by weight, and the alumino-silicate zeolite is preferably in the range of 10 to 90 Wt .-%, more preferably 30 to 60 wt .-% before, based on the total composition.

The abovementioned object is additionally achieved by a process according to the invention for the selective catalytic conversion of nitrogen-containing compounds into exhaust gas streams, the catalyst used being the composition according to the invention.

As already mentioned above, in one embodiment of the method according to the invention is the reduction of nitrogen oxides from exhaust gas streams and in the other embodiment to the oxidation of nitrogen-hydrogen compounds and / or nitrogen-containing organic compounds.

Refers basically all possible nitrogen oxides of the general formula N _x O _y that may arise, for example in motor and non-motor combustion processes, but also in industrial processes, the term "nitric oxide".

The term "catalyst" in the process according to the invention is preferably understood to mean a support which comprises a composition according to the invention. The carrier body can be formed as a bulk extrudate from the molecular sieve, or in the form of a carrier body which is coated with a composition containing the molecular sieve.

The carrier body is preferably embedded in a unit which is installed in the exhaust pipe. The unit preferably has a catalyst bed in which the carrier bodies are located. By directing the exhaust gas flow over or through the carrier body located in the catalyst bed, nitrogen oxides and, in SCO applications, nitrogen-hydrogen compounds such as ammonia and nitrogen-containing organic compounds are preferably converted into nitrogen, water (and carbon dioxide). In the SCR applications according to the invention, the nitrogen oxides are preferably reduced to N ₂ while consuming a reducing agent. In the SCO applications according to the invention, nitrogen-hydrogen compounds such as ammonia and nitrogen-containing organic compounds are preferably oxidized to N ₂ and water (and CO ₂ ) while consuming an oxidizing agent.

For the purposes of this invention, any reducing agent which is suitable for the catalytic reduction of nitrogen oxides can be used as the reducing agent in SCR applications. According to the invention, the following reducing agents are preferred: NH ₃ , urea, hydrocarbons, carbon monoxide, fuel not converted in the engine compartment during engine combustion processes, NH ₃ or urea being particularly preferred.

For the purposes of this invention, any oxidizing agent which is suitable for the catalytic oxidation of nitrogen-hydrogen compounds, such as ammonia and nitrogen-containing organic compounds, can be used as the oxidizing agent in SCO applications. According to the invention, the following oxidizing agents are preferred: oxygen, air, nitrous oxide.

After the preparation of the transition metal-modified molecular sieves, these are usually in the form of powders. These then present as a powder molecular sieves are then either formed into extrudates, deformed with the aid of oxidic and / or organic binders to Vollextrudaten / honeycomb catalysts or applied via the intermediate stage of a washcoat on ceramic or metallic carrier body, in particular honeycomb-shaped carrier body. The molecular sieve used in the process according to the invention is preferably present as a bulk extrudate or on a carrier body in the form of a coating.

In other words, the present invention thus also relates to a washcoat, a solid extrudate, an extrudate and a carrier body which comprises the composition according to the invention.

In particular, the bulk extrudates are produced in the form of honeycombs, or the carrier bodies coated with the bulk extrudate are preferably honeycomb-shaped carrier bodies.

If the molecular sieves used in the process according to the invention are in the form of a bulk extrudate, the bulk extrudate preferably comprises the composition according to the invention and at least one oxidic and / or organic binder.

The bulk extrudate is preferably prepared by extruding a mixture of the composition according to the invention and at least one oxidic and / or organic binder. The bulk extrudate is preferably a honeycomb extrudate. In addition to the binders, said mixture may also contain further metal oxides, promoters, stabilizers and / or fillers. In this mixture, the titano (silico) -alumino-phosphate is preferably in the range of 10 to 90% by weight, more preferably 30 to 60% by weight, and the alumino-silicate zeolite is preferably in the range of 10 to 90% by weight .-%, more preferably 30 to 60 wt .-% before, based on the total mixture before.

If the composition according to the invention is present on a carrier body in the form of a coating, the said mixture is preferably processed to form a washcoat which is suitable for coating carrier bodies for producing the coated carrier body. Preferably, such a washcoat comprises 5 to 50 wt .-%, more preferably 10 to 40 wt .-%, particularly preferably 15 to 35 wt .-% of Titano (silico) -alumino-phosphate and 5 to 50 wt .-%, more preferably 10 to 40 wt .-%, particularly preferably 15 to 35 wt .-% of alumino-silicate zeolite, based on the total mass of the washcoat. The washcoat of the invention contains, in addition to the above components, water or a solvent and binder. The binder of the mixture serves to bind the molecular sieves when applied to a carrier body. The solvent serves to enable both the molecular sieves and the binder to be applied in a formable form to the catalyst support.

The present invention also relates to the use of a composition according to the invention for the production of exhaust gas purifying catalyst components. Exhaust gas purifying catalyst components are units in exhaust gas streams in which the above-defined catalysts are present, and in which the nitrogen oxides are reduced to nitrogen in SCR applications or, in SCO applications, the nitrogen-hydrogen compounds such as ammonia and the nitrogen-containing organic compounds are oxidized to nitrogen.

Accordingly, the present invention also relates to exhaust gas purifying catalyst components comprising a composition of the invention.

Characters:

The 1 to 3 the present invention should further illustrate:

1 Figure ₁ shows the reaction of NH ₃ in the SCR reaction for the embodiment and Comparative Examples 1-3 (fresh) as a function of temperature.

2 : shows the conversion of NO _x in the SCR reaction for the embodiment and the comparative examples 1 to 3 (fresh) as a function of the temperature.

The present invention will now be illustrated by the following nonlimiting examples:

Examples:

Embodiment:

From 100 g of deionized water, 50 g of copper-containing TAPSO-34 (copper: 5.3 wt .-%, Süd-Chemie AG), 50 g of ferrous zeolite beta (iron: 2.2 wt .-%, Süd-Chemie Zeolites GmbH ), 22.6 g of Bindzil 2034DI (EKA Chemicals) and 7.2 g of 65% nitric acid (Merck) was prepared by mixing a washcoat. A cordierite honeycomb (⌀ 20 mm, 75 mm, 200 cpsi from Rauschert) was dipped in the washcoat. After drying, the honeycomb was heated from 40 ° C to 550 ° C within 4 h in air and held for 3 h at this temperature.

Comparative Example 1

From 800 g of deionized water, 613 g of ferrous zeolite beta (iron: 2.2% by weight, Süd-Chemie AG), 160 g of Bindzil 2034DI (EKA Chemicals) and 21.2 g of 65% nitric acid (Merck) became Washcoat made. A cordierite honeycomb (⌀ 20 mm, 75 mm, 200 cpsi from Rauschert) was dipped in the washcoat. After drying, the honeycomb was heated from 40 ° C to 550 ° C within 4 h in air and held for 3 h at this temperature.

Comparative Example 2:

From 800 g of deionized water, 666.5 g of copper-containing zeolite beta (copper: 3.8% by weight Süd-Chemie AG), 160 g of Bindzil 2034DI (EKA Chemicals) and 26.5 g of 65% nitric acid (Merck) a washcoat made. A cordierite honeycomb (⌀ 20 mm, 75 mm, 200 cpsi from Rauschert) was dipped in the washcoat. After drying, the honeycomb was heated from 40 ° C to 550 ° C within 4 h in air and held for 3 h at this temperature. Both the catalyst according to the invention and the comparative example were tested in the selective catalytic reduction of NO _x with NH ₃ . The test conditions are given in the following table.

Comparative Example 3

From 100 g of deionized water, 100 g of copper-containing TAPSO-34 (copper: 5.3 wt .-% Süd-Chemie AG), 22, g Bindzil 2034DI (EKA Chemicals) and 4.4 g of 65% nitric acid (Merck) a washcoat made. A ceramic substrate (75 mm x 150 mm x 100 mm x 200 cpsi from Rauschert) was dipped in the washcoat. After drying, the honeycomb was heated from 40 ° C to 550 ° C within 4 h in air and held for 3 h at this temperature. GHSV [h ^-1 ] Test gas composition (remainder N ₂ ) NH ₃ [ppmv] NO [ppmv] NO ₂ [ppmv] H ₂ O [% by volume] O ₂ [vol.%] 30000 230 225 30 2.6 2.7

For the test gas composition NH ₃ / NO _x = 0.91, so that the maximum NO ₃ conversion 91 can not exceed. The measured conversions for NO _x and NH ₃ are shown in the figures below.

Subsequently, all honeycombs were aged at 700 ° C in steam. For this purpose, the honeycombs were heated within 3 h at 700 ° C in a stream of nitrogen, then 10 steam was switched on for 24 h and then cooled in a stream of nitrogen back to room temperature.

The honeycombs were tested again under the same conditions.

In the catalyst according to the invention consisting of copper-containing TAPSO-34 and iron-containing zeolite beta, nitrous oxide was not detected either before or after aging.

The examples impressively show the high hydrothermal stability of the catalytic composition according to the invention. While the iron- or copper-containing comparative catalysts clearly lose their activity after the hydrothermal aging, the performance of the catalyst according to the invention is virtually unchanged.

The results for the freshly prepared catalysts and the hydrothermally aged catalysts are shown in Tables 1 to 4 and 1 and 2 compiled. Table 1: embodiment fresh aged T (avr) [° C] NH ₃ conversion [6] NO _x sales [%] T (avr) [° C] NH ₃ conversion [%] NO _x sales [%] 505.2 99.34 90.74 503.1 94.33 84.74 475.8 99.73 93.71 505.8 99.01 91.38 445.8 99.66 95.55 476.1 99.08 93.97 415.4 99.53 97.05 446 98.77 95.53 385.1 98.84 98.18 415.7 98.17 96.38 354.6 96.31 98.79 405.6 97.8 96.62 329.2 92.93 98.67 380.4 96.23 97.03 303.8 90.45 98.04 354.8 92.99 97.06 278.5 88.74 97.59 329.7 89.38 96.42 254.1 87.83 97.39 304.3 87.09 95.52 229.2 86.79 96.34 284.1 85.73 95.15 215.1 84.32 93.43 264.2 85.14 94.68 205.5 79.87 88.68 244.6 84.19 93.91 195.8 73.69 81.79 224.6 81.7 91.06 184.9 68.25 75.99 214.7 78.47 87.69 175.2 55.93 62.27 205.1 73.77 82.41 165.3 44.16 49.26 195.3 66.54 74.49 155,1 33.04 37.14 185.5 56.81 63.94 146.2 27.03 31.25 176.1 46.44 52.67 165.6 35.41 40.54 155.6 27.15 31.27 145.7 21.52 24.43 136.3 17.53 20.53 126.2 14.95 17.34 117.9 12.89 15.2 Table 2: Comparative Example 1 fresh aged T (avr) [° C] NH ₃ conversion [%] NO _x sales [%] T (avr) [° C] NH ₃ conversion [%] NO _x sales [%] 505.4 95.88 99.17 504.1 83.58 85.19 473.9 96.01 99.36 474.1 83.3 87.6 443.9 94.73 99.29 443.9 82,88 89.06 413.6 94.59 98.53 414.5 82.47 88.87 383.1 93.86 96.88 384.2 80.82 86.07 353 92.35 93.95 353.8 75.19 78.19 327.6 88.61 89.37 328.5 64.42 65.76 302.7 89,21 86.81 303 50 50.96 277.7 70.36 71.2 277.3 37.09 38.53 252.7 58.14 59.65 251.7 27,95 29.67 227.8 45.54 47.59 227 22.26 24.27 212.5 38.19 40.51 212.3 19.91 21.91 202.4 33.65 36.01 202.1 19.08 21.35 192.5 29.46 31.74 192.8 18.94 21.43 182.7 25.93 28.3 183.6 18.83 21.32 172.4 22.5 25.05 173.5 18.17 20.8 163.6 20.26 22.66 164.2 17.87 20.55 153.6 17,89 20.12 155.3 17.95 20.71 145.2 17.74 20.34 138.1 17.52 19.98 125.9 11.32 12.94 118 7,08 7.86 Table 3: Comparative Example 2 fresh aged T (avr) [° C] NH ₃ conversion [%] NO _x sales [%] T (avr) [° C] NH ₃ conversion [%] NO _x sales [%] 503.5 99.78 91.54 504.4 96.61 87.1 473.5 99.85 94.28 475 96.32 87.85 443.4 99.85 96.56 444.6 95.36 86.11 413.1 99.66 98.47 414.3 92,11 83.44 382.8 97.54 98.74 384.1 94.99 80.56 352.6 92.57 97.4 353.7 79.03 80.46 327.1 88.9 96.94 328.7 77.49 81.83 302 86.74 96.75 303.9 76.73 82.7 277.1 85.28 96.21 278.7 74.76 81.78 252.7 83.48 94.63 253.8 70 77.48 227.4 78.84 89.69 229.1 60.43 67.41 211.4 72.35 82.57 213.9 51.15 57.15 201.9 66.44 75.99 194.3 38.42 43.28 191.7 58.82 66.64 184.8 32.23 36.31 181.7 48.57 55,89 174.6 26.03 29.58 171.3. 39.31 44.81 165.1 21.46 24.23 161.4 30.64 35.12 155,1 17.4 19.85 151.5 24,03 27.71 147 15.07 17,11 141.6 19.38 22.24 137.6 13.1 15.04 132.4 16.59 19.1 128.1 11.88 13.7 123.4 14.29 16.45 Table 4 Comparative Example 3 fresh aged T (avr) c] NH ₃ sales [°] NO _x sales [%] T (avr) [° C] NH ₃ conversion [%] NO _x sales [%] 503.52 99.56 71.31 503.6 59.87 44,99 473.7 99.68 80.24 473.9 58.53 49.4 443.8 99.68 87.98 444 56.49 51.54 413.9 99.39 93.96 413 54.62 53.05 383.8 98.82 98.06 353.6 50,53 53.91 353.8 96.49 99.24 328.4 48.93 53.79 328.6 91.97 99.23 303.1 47.53 53.48 303.3 89.88 99.27 277.8 46.23 52.39 252 88.77 99.15 252.4 44.13 50.08 227 87.53 98.59 227.6 40.85 46.24 213.2 86.35 97.12 212.4 37.73 42.86 203.4 83.59 94.32 202.5 35.45 40.3 193 80,27 90.89 192.5 33.11 37.65 183.7 74.73 84.11 182.6 30.12 34.2 173.7 66.36 76.1 173.3 26.58 30.18 164.3 51.84 60.43 164 22.25 25.33 154.3 37.31 43.72 154.3 16.97 19.25 145.7 26.44 31.39 144.7 12.27 13,34 135.6 16.3 19.8 136.1 8.95 10.08 127.1 6.42 7.07

QUOTES INCLUDE IN THE DESCRIPTION

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

Cited patent literature

• EP 0585683 [0012]
• EP 103117 A1 [0014]
• US 4440871 [0014]
• US 7316727 [0014]
• EP 161488 [0029, 0032]
• US 4684617 [0029]

Cited non-patent literature

• DIN 66132 [0026]

Claims (16)

A composition comprising an aluminosilicate zeolite and a titano- (silico) -alumino-phosphate, wherein the aluminosilicate zeolite and the titano- (silico) -alumino-phosphate each have at least one transition metal selected from the group consisting of Fe, Cu, Mn, Co, Cr, V and Mo included. The composition of claim 1 wherein the aluminosilicate zeolite contains the transition metal in a range of 0.1 to 10.0 weight percent, based on the total weight of the aluminosilicate zeolite and the transition metal. A composition according to claim 1 or 2, wherein the titano- (silico) -alumino-phosphate contains the transition metal in a range from 0.1 to 10.0% by weight, based on the total mass of the titano- (silico) -alumina. Phosphate and the transition metal. A composition according to any one of claims 1 to 3, wherein the transition metal of the aluminosilicate zeolite is iron. A composition according to any one of claims 1 to 4, wherein the transition metal of the titano- (silico) -alumino-phosphate is copper. A composition according to any one of claims 1 to 5, wherein the aluminosilicate zeolite has an MFI or BEA type structure. A composition according to any one of claims 1 to 6, wherein the titano (silico) alumino-phosphate has a CHA-type structure. Washcoat, extrudate, extruded or coated carrier body comprising a composition according to one of claims 1 to 7. Process for the selective catalytic conversion of nitrogen-containing compounds in exhaust gas streams, the catalyst used being the composition according to one of Claims 1 to 7. The method of claim 9, wherein the reaction of nitrogen-containing compounds is the reduction of nitrogen oxides. Process according to Claim 10, in which NH ₃ , urea, carbon monoxide or hydrocarbon compounds are used as the reducing agent. The process of claim 9, wherein the reaction of nitrogen-containing compounds is the oxidation of nitrogen-hydrogen compounds and / or nitrogen-containing organic compounds. Process according to Claim 12, in which oxygen-containing gases, air or nitrous oxide are used as the oxidizing agent. Use of a composition according to any one of claims 1 to 7 for the selective catalytic conversion of nitrogen-containing compounds in exhaust gas streams. Use of a composition according to any one of claims 1 to 7 for the production of an exhaust gas purifying catalyst component. An exhaust gas purifying catalyst component comprising a composition according to any one of claims 1 to 7.

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