DE2858796C2 - Metal-contg. ZSM-5 type zeolites - Google Patents

Abstract

New zeolites are characterised by their molar compsn. and by their X-ray diffraction pattern (which is characteristic of ZSM-5 zeolites). The molar compsn. in the anhydrous state is (R2O,M2'/nO)w:(Al2O3)x:(SiO2)y:(M"2/nO)z (where 0.5 <w/y <3;y/x> 20;0 <z/x <100; R is a N-contg. cation, pref. tetra (2-5C alkyl)ammonium; M' is an alkali metal; M" is In, B, Ru, Pt, Cr, a rare earth metal, V, Pd, Mo, Hg, Te and/or Ag; n is the valence of M' or M").Also claimed are zeolites with the above compsn. in which R and/or M' are replaced by alkylammonium, metal, NH4 and/or H cations, as well as products obtd. by heat treating these zeolites at >260 degrees C.The zeolites are useful as hydrocarbon conversion catalysts, e.g.for cracking, hydrocracking, isomerisation, olefin polymerisation, reforming, alkylation, toluene disproportion, and conversion of methanol to hydrocarbons (esp. p-xylene). They have high selectivity and stability

Description

The invention relates to a crystalline alumi nosilicate zeolite according to the preamble of claim 1, a method for its production and its use dung.

Both natural and synthetic zeolite materials possess, as has already been shown, catalytic Properties for different types of hydrocarbons conversions. Certain zeolite materials are ordered porous crystalline aluminosilicates with a defined crystalline Structure in which a large number of smaller cavities located by a number of even smaller channels connected to each other. These cavities and channels are in exactly uniform in size. Because the dimensions of this Pores are made to adsorb molecules certain dimensions, while those with larger dimensions Reject dimensions, these materials are called so-called Known molecular sieves; they are becoming usable for this Properties used in a variety of applications.

Such molecular sieves, d. H. both natural and Synthetic, for example, are a great variety of crystalline aluminosilicates containing positive ions. These aluminosilicates can be considered rigid three-dimensional  Described networks of SiO₄ and AlO₄, wherein the Tetrahedra are cross-linked by the common oxygen atoms so that the overall ratio of aluminum atoms and silicon atoms to oxygen has the value of 1: 2. The electrovalence the aluminum-containing tetrahedron is thereby balanced, that in the crystal cations z. B. of an alkali metal or are contained by an alkaline earth metal. This can be, for example be expressed by a formula, where the ratio from Al to the number of different cations, e.g. Ca / 2, Sr / 2, Na, K or Li, corresponds to one unit. The cations of the crystalline zeolite can be either complete or partially covered by other metal cations Use of ion exchange techniques to be replaced (US-PS 37 02 886). With the help of such Cation exchange is the possibility that the size the pores in the given aluminosilicate by suitable Selection of the appropriate cations is varied. The rooms between the tetrahedra are formed by water molecules in front of the Dehydration taken.

According to US-PS 39 41 871 is a crystalline organometallic Silicate with a high silica / alumina ratio prepared from a reaction mixture containing tin, Cal contains cium, nickel or zinc oxide. Furthermore, from the DE-OS 27 42 971 chromium and vanadium-containing Aluminosili cate of the ZSM-5 type known.

Other known ways of working already led to Formation of a large variety of synthetic crystalline Aluminosilicates. These aluminosilicates are by letters or other common symbols have been described  for example by zeolite A (US Pat. No. 2,882,243), zeolite X. (US-PS 28 82 244), zeolite ZSM-5 (US-PS 37 02 886), zeolite ZSM-11 (US-PS 37 09 979), ZSM-12 (US-PS 38 32 449) and zeolite ZSM-35 (US-PS 40 16 245).

The object of the invention is zeolites of high thermal Stability and with superior catalytic properties to provide.

This is inventively gekenn with the characterized in claim 1 reached aluminosilicate zeolite. advantageous Embodiments of this zeolite are in claims 2 and 3. In claim 4 is a preferred Process for the preparation of an alumi according to the invention nosilicate zeolite, and in claim 5 a preferred use of the invention Alumi nosilicatzeolith.

The zeolite according to the invention has that in claim 1 given X-ray diffraction pattern for zeolites characteristic of the ZSM-5 type.  

The values of the X - ray diffraction diagram of the Claim 1 are determined by conventional procedures Service. The irradiation consisted of the K-alpha doublet of Copper; a scintillation counter spectrometer with a measuring strip writer was used. The peak values (I) and the positions as a function of 2 × theta (where Theta means the Bragg angle) were from the spectrometer strip read. From this, the relative intensities (100 I / I₀,  where I₀ is the intensity of the strongest line or peak means) and d (obs.), d. H. the lattice spacings in nanometers units, calculated according to the recorded lines. In claim 1, the relative intensities each with strong, weak or very strong. On such X-ray diffraction pattern is for all kinds characteristic of the mixtures according to the invention. ion exchange of sodium ions with other cations essentially results the same picture with some minor shifts in the picture Lattice spacing and variation in relative intensity. Other minor variations may vary depending on Silicon / aluminum ratio in the particular sample and from Extent of thermal treatment occur.

The zeolite according to the invention has in the anhydrous state with reference on the molar ratios of the oxides following formula:

where W / X is from <0.5 to <3, Y / X is <20 and Z / X goes from <zero to <~100 and further R is a nitrogen containing cation means. For example, R can be primary Amines containing 2 to 10 carbon atoms and ammonium cations, preferably tetraalkylammonium cations, wherein the alkyl groups contain 2 to 5 carbon atoms; M ' represents a metal from Group IA of the Periodic Table; n means the valence from M 'or M' '. M '' are  Platinum, palladium and / or silver.

Whether M '' as a metal or as a metal compound available is not known. According to the above formula comes the presence of M "in any of the various states and also in varying amounts. If this is present, for example, in the occluded state, can its concentration in relation to aluminum in the synthesized zeolites up to, but less than about 100 rich.

According to claim 4 gives a reaction mixture, the starting sources of tetra propylammonium cations (from the hydroxides), sodium oxide, Silica, water and sources of platinum, palladium and / or Silver and optionally alumina contains a zeolite ZSM-5, which has unexpectedly improved properties has.

The crystalline aluminosilicates, which according to the Invention have been produced according to high-thermal Stability and show superior catalytic properties.  

The original alkali metal may at least partially wise according to known procedures by ion exchange be exchanged with other cations. Preferred exchange Cations are, for example, metal ions, ammonium ions, water stoffionen and mixtures thereof. Particularly preferred cations are those who make the zeolite catalytically active, in particular for hydrocarbon conversion. in this connection is it z. B. to hydrogen, metals of groups II and VIII of the periodic table and manganese.

The silica / alumina mole ratio of the zeolite is suitably greater than 35 and extends to about 3000.

The zeolites according to the invention have a high degree thermal stability, which makes them suitable for use Process made particularly effective under elevated temperatures become. The mixture can be made using materials which are the suitable components of the zeolite deliver. Such components are for an aluminosilicate for example, sodium aluminate, alumina, sodium silicate, Silica hydrosol, silica gel, silica, Sodium hydroxide or a tetrapropylammonium compound, z. B. tetrapropylammonium hydroxide. It is evident that each Component used in the reaction mixture for the preparation of the zeolite is harnessed by one or more original reaction components can be introduced; the components can be together in any order  be mixed. For example, sodium can be replaced by an aqueous Solution of sodium hydroxide or by an aqueous solution of Sodium silicate are introduced; tetrapropylammonium can be introduced by the bromide salt. The reaction Mixture may be either batchwise or continuous be presented. The crystal size and the crystallization time of the mixture vary depending on the one used Reaction mixture. At very high silica / alumina Conditions which according to the invention preferably more than 35 can reach up to about 3000 or higher, especially preferably about 70 to about 500, it does not need to be be that one is a source of alumina for Reaction mixture gives, as the remaining quantities at other Be sufficient reaction components.

The zeolite can be prepared from a reaction mixture which behaves the composition (with respect to the moles the oxides or in% values of the total moles of Oxides) within the following ranges:

Table I

Typical reaction conditions are heating the above reaction mixture to a Temperature of about 95 ° C to 175 ° C for a period of time from about 6 hours to 120 days. A preferred temperature Range goes from about 100 ° C to 175 ° C at a time for a temperature in such a range of about 12 Hours to 8 days are enough.

The digestion of the gel particles is carried out until Crystals are formed. The solid product is from the reaction medium separated, z. B. by cooling the mixture to room temperature, filtration and washing with water.

The above product is dried, for. B. at 110 ° C for a period of about 8 to 24 Hours. Of course, if desired, even milder be conditions are used, for. B. room temperature under vacuum.

In the zeolite, the alkali metal contained therein by a great variety of other cations accordingly be exchanged known practices. Typical exchange Cations are, for example, hydrogen, ammonium and metal cations and corresponding mixtures thereof. Regarding the Metal exchange cations are especially cations of such Preference for metals, such as rare earth metals, manganese and Calcium, and also metals from Groups II and VIII of the Periodic table, z. As zinc or platinum.  

Typical ion exchange techniques are that the zeolite with a salt of the desired exchange cation or the desired Austauschkationen brought into contact becomes. Although a large variety of salts are used can, chlorides, nitrates and sulfates are particularly preferred.

For illustration, such are General description of ion exchange techniques in large numbers, z. In US Pat. Nos. 3,140,249, 3,140,251 and 3,140,253.

Following contact with the saline solution of the desired exchange cation, the zeolites are then preferably washed with water and at a temperature in the Dried range from 66 ° C to about 316 ° C; This is followed by calcination in air or in another inert gas at temperatures in the range of about 260 ° C to 816 ° C during periods in the Range from 1 to 48 hours or more.

Regardless of the cations that the sodium in the Replace synthesized form, the spatial arrangement remains the aluminum, silicon and oxygen atoms, in principle form the crystal lattice or crystal network of the zeolite, by the described exchange of sodium or of the other alkali metals substantially unchanged, as by Recording a powder X-ray diagram of the ion-exchanged materials has been determined. Such X-ray diagrams of the ion-exchanged  Product show a pattern essentially according to those as indicated in the X-ray diffraction diagram of claim 1.

The aluminosilicates of the invention are in a produced large variety of particle sizes. Generally speaking the particles in the form of a powder, a granule or a formed product, for. B. in the form of an extrudate having a sufficient particle size so that they can be replaced by a 2-mesh screen (after Tyler) go through and from a 400- Mesh screen (after Tyler) are held back. In such cases where the catalyst is formed, for example by Extrusion, the aluminosilicate can be extruded before drying be dried or partially dried and then be extruded.

For many catalysts, it is desirable that the zeolite mixed with another material that is opposite to the Temperatures and other conditions that are organic Conversion method can be applied, is resistant. Such Materials are, for example, active and inactive materials and synthetic or naturally occurring zeolites as well such as inorganic materials such as clays and clays, silicon dioxide and / or metal oxides. The latter can either naturally occurring or in the form of gelatinous precipitation or gels, including mixtures of silica and other metal oxides are present. The use of an active Material in connection with the zeolite mixture according to the invention,  d. H. combined with it, leads to the improvement of Conversion and / or selectivity to the catalyst in certain organic conversion processes. Inactive matter alienes are suitably used as diluents for Regulation of the degree of conversion in a given process, so that the products in an economical way and in the desired Form without using other means of controlling the reaction rate can be obtained. Usually the zeolite materials in naturally occurring clays or clays, eg. B. Bentonite or kaolin, incorporated, so that the breakage Strength of the catalyst under technical working conditions is improved. These materials, d. H. Clays and clays, Oxides, etc., act as a binder for the catalyst. He wishes is the formation of a catalyst with good breaking strength, because in a petroleum refinery, the catalyst often one rough handling is liable to break the catalyst can lead to powdery materials, resulting in Problems in the operations result. These clay binders are therefore for the purpose of improving the breaking strength of Catalyst has been used.

Naturally occurring clays of the clay, which with the Catalyst can be mixed, for example, the those from the groups of montmorillonite and kaolin; in this connection is it z. B. the subbentonites and kaolins, the usually as Dixie, McNamee, Georgia and Florida Tone others, wherein the major mineral halloysite, kaolinite, dickite, nacrit or anauxite.  Such clays can in the raw state, as they degraded or ge be used, or an initial calcination, Acid treatment or chemical modification.

In addition to the above materials, the Catalyst assembled with a porous matrix material be, z. For example, silica, alumina, silicon dioxide / alumina, silica / Magnesia, silica / zirconia, silica / thor oxide, silica / beryllium oxide, silica / titania, further with ternary compositions, such as. As silica / Alu minium oxide / thoria, silica / alumina / zirconia, Silica / alumina / magnesia or silica / Magnesium oxide / zirconium oxide. The matrix material can be in shape of a cogel. The relative proportions of finely divided crystalline aluminosilicate and inorganic oxide gel matrix Material vary greatly with the content of the crystalline aluminosilicate ranging between about 1 and about 90% by weight, and more preferably in the range of about 2 to about 50% by weight of the composition when the mixture is in the form of Pearls is made.

While the zeolite of the invention as a catalyst in cracking and hydrocracking, it is also extraordinary good as a catalyst suitable for other petroleum refining operations. The latter methods are for example Isomerization of n-paraffins and naphthenes, polymerization  of compounds which are an olefinic or an acetylenic Carbon / carbon bond included, for. B. isobutylene and butene-1, reforming, alkylation, isomerization of polyalkyl substituted aromatics, e.g. As ortho-xylene, and Disproportionation of aromatics, eg. As toluene, wherein a Mixture of benzene, xylenes and higher methylbenzenes formed becomes. The catalysts have exceptionally high selectivities and give under the conditions of hydrocarbon conversion high percentages of the desired products with respect to the Total products compared to known zeolitic carbon hydrogen conversion catalysts.

As stated above, the invention Zeolites are also useful in other catalytic processes, z. As in the catalytic cracking of hydrocarbons and in Hydrocracking. Besides the thermal stability among the mentioned conditions, this group of zeolites gives a Conversion of cracked oil to lower grade materials Molecular weights and boiling points, of greater technical Meaning are. The ability to physical stability under high temperatures and / or in the presence of high Temperature steam is extraordinary for a cracking catalyst important. During catalytic conversion, the reaction is which takes place, essentially a cracking process Formation of hydrocarbons. However, this cracking process accompanied by a variety of complex side reactions, z. B. aromatization, polymerization, alkylation od. Like. As a result of these complex reactions, a carbon  like or carbonaceous deposit on the catalyst dejected, referred to in the petroleum engineering as coke becomes. The coke precipitate on the catalyst tends to serious deterioration of catalyst efficiency for the desired main reaction and the substantial decrease of Conversion rate and / or the selectivity of such Ver proceedings. Therefore, it is common to add the catalyst after Coke on top of it, removes it and puts it through Burning off the coke in a stream of an oxidizing gas regenerated. The regenerated catalyst is converted into recycled stage of the process cycle. The thermal Stability of the zeolite according to the invention is with regard to these requirements very beneficial.

The products may be either in the alkali metal form, z. B. in the sodium form, or in the ammonium form, in the Hydrogen form or in another monovalent or more valent cation form can be used. Preferably, the one or the other of the latter two forms is inserted puts. You can also in intimate mixing with a hydrogenation component, z. Tungsten, vanadium, molybdenum, rhenium, nickel, Cobalt, chromium, manganese or a precious metal, such as platinum or Palladium, used when a hydrogenation / dehydrogenation Function should be exercised. Such a component can into the mixture by exchange, impregnation or physical Interference are introduced. So it can be one  Component by impregnation in or on the zeolite be brought, for. In the case of platinum by treatment of the Zeolites with a platinum metal-containing ion. suitable Platinum compounds are, for example, chloroplatinic acid, Platinum chloride and various compounds containing a platinum Ammine complex included.

The compounds of the useful platinum metals or other metals can be classified as Ver compounds in which the metal contained in the cation of the compound and on the other hand compounds in which it is in the anion of this Connection is included. Both types of connections that the Metal in the ionic state can be used. A solution in which platinum metals in the form of a cation or a cationic complex, e.g. As Pt (NH₃) ₆Cl₄ contain are particularly useful. For some hydrocarbons Conversion process is this precious metal form of the relevant Catalyst not required, eg. B. in the liquid phase Isomerization of ortho-xylene at low temperature.

When used as either an adsorbent or as a Catalyst in one of the aforementioned methods takes place, the catalyst should at least partially dehydrati be siert. This can be done by heating to a temperature in the Range from 200 ° to 600 ° C in an atmosphere such as air, Nitrogen etc., and at atmospheric or subatmospheric Press for between 1 minute and 48 hours respectively. The dehydration can be at lower temperatures  also take place in that the catalyst only in one Vacuum is introduced; however, this is a longer period of time required to give adequate dehydration grad receives.

The invention will be described below with reference to some examples illustrated in more detail.

example 1 Solution 1 G Na silicate (Q quality) 240 Distilled H₂O 300 540

Solution 2 G Distilled H₂O 410 tetrapropylammoniumbromide 30 Conc. HCl 35 H₂ PtCl₆ · nH₂O 2

Typical analytical values of the sodium silicate are:
8.9% Na₂O, 28.7% SiO₂, 62.4% H₂O.

The solution 1 was in a four-necked flask with 2 liters of Fas introduced capacity with overhead stirrer. The solution 2 was added with stirring. The mixture became highly gelatinous.  A small amount of H-ZSM-5 (about 0.1 g) became for inoculation added. Then the heating started, and the solution was on heated to about 96 ° C. A Variac setting served as single control of temperature at change ± 3 ° C in Dependence on voltage changes during the day. After a few days, the solution lost its gelatinous Character and she became more chalky. The crystallization (determined by X-radiation) claimed 5 to 6 days. The catalyst was filtered and distilled with about 4 liters Tem H₂O washed. The yield was 60 to 70 g of catalyst.

The catalyst was dried at 70 ° C and in a Crucible of a muffle furnace at 23.9 ° to 538 ° C calcined for 12 hours. Then the catalyst became in a 200 ml flask together with 100 cc H₂O and 10 g NH₄NO₃ introduced and boiled at 100 ° C for 1 hour at reflux. The catalyst was filtered off, washed and repeated Exchanged for 5 hours with NH₄NO₃. After that, the Catalyst again filtered, washed and repeated approximately Exchanged for 16 hours. Subsequently, the catalyst became filtered, washed thoroughly and at 70 ° C for about 6 hours dried. Then the catalyst was again in a muffle furnace calcined at 23.9 ° to 538 ° C for 6 hours.

The powder X-ray diagram of the crystalline product, namely both in the synthesized Form as well as after the treatments mentioned above are in Table II below.  

While this example uses the Shows ammonium cations, it can be seen that others Cations, z. As those of alkylammonium, metals or Hydrogen, can be used.

As can be seen from Table II, smaller ones Differences between the X-ray diagrams of the synthesized zeolite and zeolite Ion exchange and thermal treatments observed. These Differences are switching from singles to doublets and others Doublets to singlets between the two patterns as Result of lower shifts in the interplanetary Distances and variations in the relative intensities. These observed differences illustrate lower ones Variations in the lattice parameters and in the crystal symmetry.  

Table II

example 2

This embodiment corresponds to Example 1, however with the exception that 5 g of silver acetate (instead of chromium connection) were used. The X-ray analysis showed a diffraction pattern corresponding to that of the above standing example.

Using the catalyst according to the invention, containing a hydrogenation component, heavy oil residual materials, Cyclus materials and other hydrocrackable feeds at temperatures between 204 ° C and 441 ° C using molar ratios of hydrogen to  Hydrocarbon feed in the range between 2 and 80 hydrocracked. The applied pressure varies between 0.68 and 170.13 bar (gauge) and the hourly space velocity of the liquid is between 0.1 and 10.

When the catalyst according to the invention for used catalytic cracking, the hydrocarbon Cracking materials in an hourly space flow velocity of the liquid between about 0.5 and 50, a temperature between about 288 ° and 593 ° C. and a pressure between about subatmospheric pressures and cracked several hundred atmospheres.

Using a catalytically active form of zeolites according to the invention containing hydrogenation component For example, reforming feedstocks can be used at a temperature be reformed between 371 ° C and 538 ° C. The pressure can be between 6.8 and 69 bar (overpressure) (100 and 1000 psig), but preferably between 13.61 and 47.64 bar. The hourly Space velocity of the liquid is generally between 0.1 and 10, preferably between 0.5 and 4; the Hydrogen / hydrocarbon mole ratio is generally between 1 and 20, preferably between 4 and 12.

The catalyst can also be used for hydroisomerization be used by normal-paraffins, if he is with a  Hydrogenation component, e.g. B. platinum, is provided. The Hydroisomerization is carried out at a temperature between 93 ° and 371 ° C, preferably between 149 ° and 288 ° C, at an hourly space velocity the liquid between 0.01 and 2, preferably between 0.25 and 0.50, using hydrogen in such amount that the hydrogen / hydrocarbon mole ratio between 1: 1 and 5: 1. In addition, the catalyst can for olefin isomerization using temperatures between -1.11 ° C and 260 ° C and for the methanol and dimethyl ether conversion.

Other reactions using the invention according to the catalyst containing metal, for. Platinum, can be carried out, for example, hydrogenation / Dehydration reactions and desulfurization reactions and for hydrocarbon oxidation.

The products were made according to the above tested conversion process. It resulted in the following results.

Evaluation of the products toluene disproportionation

Table IV below lists the data that using a sample of the hydrogen form  of the zeolite as in Example 1 in toluene conversion were obtained. The run was at 40.83 bar (over pressure, 3.5 WHSV and a H₂ / hydrocarbon ratio 2/1 executed. The hydrogen form was after work obtained according to Example 1.

Table IV

hydrocracking

Table XII below illustrates the Results obtained in the conversion of buffalo naphtha (106 ° up to 185 ° C); using the hydrogen form of the zeolite at 482 ° and 538 ° C (900 ° and 1000 ° F) were. The conversion conditions were 6.8 bar (Overpressure), 5 WHSV and a H₂ / HC ratio of 3/1 (HC = Hydrocarbon). The naphtha product corresponded to the own according to the table. The hydrogen form of the zeolite was obtained according to the above information.  

Table V

106 ° to 185 ° C Buffalo naphtha (% by weight) C₆ 0.8 benzene 0.1 C₇ 20.1 toluene 3.2 C₈ 31.8 C₈Ar 9.5 C₉⁺ 29.1 C₉⁺Ar 5.0

Reaction of methanol

Evaporated methanol was passed through the hydrogen form of the zeolites prepared using platinum passes. The working conditions and the results are in Table VI below.  

Table VI

xylene isomerization

The same zeolite as used for the investigations according to Table VI was used in terms of its Activity tested in xylene isomerization. The following Table VII illustrates the working conditions and the Results.

Table VII

360 ° C; 13.61 bar (gauge); 5 WHSV; 4/1 H₂ / HC

The feed as shown in Table VIII below was given the same catalyst as used in the Tests according to Tables VI and VII were used, passed under the conditions mentioned. A compilation the results are shown in Table VIII below.

Table VIII Temp. ° C 538 bar 0 H₂ 0 WHSV 1

Claims (7)

1. Crystalline aluminosilicate zeolite with the following X-ray diffraction diagram: characterized in that it has the following formula (in the anhydrous state) based on the molar ratios of the oxides: where W / X has a value between <0.5 and <3, Y / X has a value <20 and Z / X has a value of <zero and <~100, R is a nitrogen-containing cation, M 'is a metal from group IA Periodic table, M '' platinum, palladium and / or silver and n the valency of the metal M '' signeu and that the zeolite from a reaction mixture containing the metal M '' was prepared. 2. Crystalline aluminosilicate zeolite according to claim 1, characterized in that R is a tetraalkylammonium cation, wherein the alkyl groups are 2 to 5 carbon contain atoms. 3. Crystalline aluminosilicate zeolite according to claim 1 or 2, characterized in that R and / or M 'by Alkylammonium, metal, ammonium cations and / or what are replaced by hydrogen. 4. A process for preparing a crystalline aluminosilicate zeolite according to claim 1 to 3 by forming a reaction mixture containing starting sources of tetra propylammoniumverbindungen, silica, alumina and sodium, heating the mixture until crystals are formed, optionally Inonenaustauschen and calcining, characterized in that the reaction mixture also contains a metal M ", where M" is platinum, palladium and / or silver, and the mixture has the following molar ratios of the oxides or% values of the total moles of oxides: OH⁻ / SiO₂ 0.07-1.0 R₄N⁺ / (R₄N⁺ + Na⁺) 0.2 to 0.95 H₂O / OH⁻ 10-300 SiO₂ / Al₂O₃ 50-3000 Metal oxide of metal M "(% of total oxides) 1 × 10 ^-6 -1.0 where R is a propyl radical. 5. Use of the crystalline aluminosilicate zeolite Lithen according to one of claims 1 to 3 for conversion an organic feedstock.