FR2504512A1 - SYNTHETIC CRYSTALLINE COMPOSITIONS OF RUTHENIUM ALUMINOSILICATE, THEIR PREPARATION AND THEIR APPLICATIONS - Google Patents

Abstract

Crystalline ruthenium aluminosilicate compositions are prepared by digesting a reaction mixture which contains a ruthenium<2+> salt, an aluminium salt, a tetraalkylammonium compound, sodium hydroxide, a silicon oxide and water. The compositions can be used as catalysts in the conversion of oxygen compounds, such as dimethyl ether and methanol, into hydrocarbons, in the polymerisation of olefins and in the conversion of synthesis gas into hydrocarbons and/or oxygenated compounds.

Description

Synthetic crystalline compositions of ruthenium aluminosilicate, their preparation and applications.

The invention relates to novel crystalline silicate compositions, particularly ruthenium aluminosilicate.

Further, the invention relates to processes for preparing these novel crystalline aluminosilicate compositions, a process for activating them to increase their utility in certain catalytic conversion processes and their application to such conversion processes.

It is known that both natural and synthetic zeolite materials have catalytic properties for various types of reactions, especially those of conversion of hydrocarbons.

The well-known crystalline aluminosilicate zeolites are commonly referred to as "molecular sieves" and are characterized by their highly ordered crystal structure and uniformly sized pores and can be distinguished from each other on the basis of composition, crystal structure, properties of water. adsorption and the like. The term "molecular sieve" derives from the property of zeolite materials of selectively adsorbing molecules based on their size and shape.

The methods of making these synthetic crystalline zeolites are well known. A family of crystalline aluminosilicate zeolites called ZSM-5 is described in US Pat. No. 3,702,886.

The ZSM-5 family of compositions exhibit a characteristic X-ray diffraction pattern and can be identified, in oxide molar ratios, as follows:
0.9 + 0.2M2 / nO: W205: 5 to 100 Y02: zH20,
M being a cation, n the valence of this cation, W representing aluminum or gallium, Y being silicon or germanium and z being from 0 to 40. In a preferred synthetic form, the zeolite responds, in molar ratios of oxides, with the following formula: 0.9 + 0.2M2 / nO: A1203: 5 to 100Si02: zH20,
M represents a mixture of alkali metal cations, especially sodium, and tetraalkylammonium cations, the alkyl groups of which preferably contain 2 to 5 carbon atoms.

US Pat. No. 3,941,871 relates to novel crystalline metal organosilicates practically free from group metals.
IIIA, that is to say aluminum and / or gallium. It is indicated that the amount of alumina contained in the known zeolites appears directly related to the acidity characteristics of the product obtained and that a low alumina content is recognized as advantageous if one wishes to achieve a low degree of acidity, which in many catalytic reactions results in poor coke-forming properties and low aging rates.

A typical process for obtaining organosilicates consists in reacting a mixture containing a compound of tetraalkylammonium, sodium hydroxide, an oxide of a metal other than of the group
IIIA, an oxide of silicon and water, until crystals of metallic organosilicates are formed. It is also stated in said patent that the family of crystalline metal organosilicates has a defined X-ray diffraction pattern which is similar to that of ZSM-5 zeolites. Small amounts of alumina are contemplated in the patent and are attributable primarily to the presence of aluminum as an impurity in the reagents and / or equipment used.

US Patent 3,844,835 describes crystalline silica compositions. The crystalline silicas can also contain a metallic adjuvant, which can be chosen from the elements of groups IIIA, VB or VIB.

US Patent 4,088,605 relates to the synthesis of a zeolite such as ZSM-5 which contains an outer layer free of aluminum. Column 10, lines 20 onwards, says that in order to form the aluminum-free outer layer it is also essential to remove the reactive aluminum from the reaction mixture. It is therefore necessary, as indicated, to treat the zeolite and replace the crystallization medium with a mixture free of aluminum to obtain crystallization of SiO 2 on the surface of the zeolite, which can be done by completely replacing the mixing or complexing any aluminum ions remaining in the original mixture with reagents such as gluconic acid or ethylenediaminetetraacetic acid (EDTA).

Crystalline borosilicate compositions are described in DE-OS 27 46 79n. This published application relates especially to borosilicates, which are prepared by the usual processes for obtaining aluminosilicate zeolites. It is stated therein that, in cases where a deliberate effort is made to remove aluminum from the borosilicate crystal structure because of its deleterious influence on particular conversion processes, the SiO 2 / Al 2 O 3 molar ratios can easily exceed. 2000 to 3000 and that, generally, this ratio is only limited by the accessibility of raw materials free of aluminum.

DE-OS 28 48 849 relates to crystalline aluminosilicates of the ZSM-5 series of zeolites. These particular zeolites have a silica / alumina molar ratio of greater than 20 and are prepared starting from a mixture containing a source of silica, alumina, a quaternary alkyl ammonium compound and a metal compound, for example of metals of carbon. group VIII such as ruthenium, palladium and platinum. In Example 2, the crystalline aluminosilicate is prepared starting from a reaction mixture containing RuCl3 and, in Example 3, the mixture contains H2PtC16.nH2û.

Although zeolite catalysts exhibiting a wide variety of catalytic and adsorbent properties are known, there is still a need for crystalline materials having different and / or enhanced catalytic properties. For example, an important use of a crystalline material is in processes for the conversion of oxygenates, for example in the conversion of dimethyl ether and methanol to aliphatic compounds, as well as in the conversion of synthesis gas or hydrocarbons. such as ethylene with a notable level of conversion and selectivity.

The present invention relates to crystalline silicates of metals of group VIII which can be identified, in molar oxide ratios, by the following formula (0.10) R20: (0.05a20) Ru20: (0.05 to 10) A1203 : 100Si02: (Ca200) H2O:
m where R is tetraalkylammonium, hydrogen, alkali metal, metal, ammonium or a mixture thereof, n is the valence of R and m is the valence of ruthenium. The crystalline ruthenium aluminosilicates of the invention have an X-ray diffraction pattern which is substantially that of a ZSM-5 zeolite.

The ruthenium aluminosilicate according to the invention can be prepared by a process characterized by the following steps: a mixture is prepared containing a Ru2 + salt, an aluminum salt, a tetraalkylammonium compound, an alkali metal hydroxide, silica and water, the composition of the mixture in molar oxide ratios falling within the following ranges OH- / Si02 0.05 to 3 + + A +) 0.01 to 1 H20 / 0H- 10 to 800
SiO2 / Ru2 / mO 5 to 2000
Si02 / A1203 10 to 2000 in which Q + is a quaternary ammonium ion and A + an alkali metal ion, the mixture is maintained at a temperature of about 50 to 2500C until crystals of the silicate are formed and the mixture is maintained. separates and collects the crystals.

Oxygenated derivatives of hydrocarbons such as methanol, dimethyl ether and mixtures thereof can be converted into hydrocarbons by contacting them, under conversion conditions, with the crystalline ruthenium aluminosilicate composition of the invention. Similarly, a synthesis gas, comprising hydrogen and carbon monoxide, can be converted into a hydrocarbon and / or oxygenates, by contacting this synthesis gas, under conversion conditions, with the crystalline composition. ruthenium aluminosilicate of the invention. Some of the compositions of the invention promote the polymerization of ethylene to give heavier hydrocarbons, including aromatics.

The invention therefore relates to a class of crystalline compositions of ruthenium aluminosilicate. These compositions are prepared by a process which requires the presence of a source of ruthenium in the reaction mixture.

According to the invention, there are provided crystalline ruthenium aluminosilicates which can be identified by the molar ratios of oxides indicated above. The silicate as prepared also contains a tetraalkylammonium cation.

Members of this family of ruthenium aluminosilicates have a defined crystal structure. The X-ray diffraction pattern of the dried crystalline material of the invention is substantially similar to that of a ZSM-5 zeolite. Although the X-ray diffraction pattern does not distinguish the ruthenium aluminosilicates according to the invention from a ZSM-5 zeolite, there are several important points which distinguish them. Zeolites
ZSM-5 contain significant amounts of aluminum, but contain virtually no ruthenium in their crystal structure. The aluminosilicates of the invention contain in their crystal structure significant amounts of ruthenium, which cannot be removed by conventional ion exchange techniques. Ruthenium aluminosilicates can be distinguished from zeolite ZSM-5 in other respects. In particular, the catalytic activity of the ruthenium aluminosilicates of the invention differs notably from that of a zeolite of the ZSM-5 type. .

To prepare the ruthenium aluminosilicates of the invention, it is possible to heat a reaction mixture comprising tetraalkylammonium ions (for example tetrapropylammonium) originating for example from bromide or from hydroxide, an alkali metal hydroxide such as sodium, a compound of ruthenium, a compound of aluminum, an oxide of silicon and water and whose composition, in molar ratios, falls within the following ranges:
Large Preferential OH- / Si02 0.05 to 3 0.20 to 0.90 Q + / (Q + + A +) 0.01 to 1 0.05 to 0.8 H20 / 0H 10 to 800 60 to 500 Si02 / Ru2 / mO 5 to 2000 10 to 1000
SiO 2 / Al 2 O 3 10 to 2000 20 to 500 in which Q + is a quaternary ammonium ion and A + an alkali metal ion, and the mixture is maintained at elevated temperature for a sufficient time to form crystals of the product. Typical reaction conditions are heating the reaction mixture at elevated temperature, for example from about 50 to 2500C and even above, for about 6 hours to 60 days. The preferred temperature is approximately 100 to 1900C, for approximately 1 to 16 days. The mixture can be heated at high pressure, for example in an autoclave, or at normal pressure, for example at reflux. The preferred heating method is reflux.

As is common in the manufacture of aluminosilicate compositions, when refluxing the mixture is used, large amounts of sodium chloride are added to it together with sulfuric acid to ensure crystallization of the product. Thus, in the reflux preparation, the SiO 2 / Ru 2 O 3, OH / SiO 2 and the like ratios tend to be different from what they are in the autoclave.

The gel particles are digested until crystals are formed. The solid product is separated from the reaction medium, for example by cooling the whole to room temperature, filtering and washing with water.

The above product is dried, for example at 1100 for about 8 to 24 hours or more. Of course, if desired, more moderate conditions can be applied, for example room temperature under vacuum.

An important aspect of the invention is a method of activating the novel crystalline composition of the invention for improved use in various conversion methods. In general, the activation process consists of
- a) heat-treating the dried silicate composition, for example between 200 and 9000C approximately, preferably between 400 and 6000C approximately, for approximately 1 to 60 hours, preferably approximately 10 to 20 hours, in an atmosphere containing molecular oxygen.

In a preferred embodiment, the activation method comprises the following steps:
- 1) the dried silicate composition is heat treated, for example between 200 and 9000C approximately, preferably between 400 and 6O00C approximately, for approximately 1 to 60 hours, preferably approximately 10 to 20 hours,
- 2) the thermally treated silicate composition is subjected to ion exchange with a material which, when subsequently heat treated, decomposes to give a composition which contains a hydrogen cation,
- 3) the silicate composition which has undergone the exchange is washed and dried,
- 4) the dried silicate is heat treated by applying the process of step 1.

Those skilled in the art will understand that steps 1 to 4 inclusive of the preferred embodiment and step a above are well known and represent methods commonly used to activate zeolite type catalysts. The composition of the invention can advantageously be used in the form obtained after step 4 or after step a. The heat treatment can be carried out in any atmosphere, in known manner, and preferably in air.

When desired, the activation process may optionally include the redox treatment described in the patent.
BE 886 090. This treatment comprises a heat treatment carried out with a reducing agent and is carried out, after step a or step 4 of the above activation processes, as follows.
b) or 5), the heated silicate composition is treated with a reducing agent for about 1 to 80 hours, preferably about 2 to 40 hours, between 200 and 9000C approximately, preferably between 400 and 6000C approximately, and
c) or 6), the reduced silicate is heat treated using the process of step a or step 1, respectively.

Any reducing agent or a compound which, under the conditions of the treatment, forms a reducing agent, such as dimethyl ether, can be used. Dimethyl ether and hydrogen are preferred, because of their demonstrated efficacy.

The activation process described herein, which does not include "redox treatment", results in a catalytically active composition, which exhibits useful rates of conversion and selectivity in reactions catalyzed by the compositions of the invention and is the preferential activation process. Although the inclusion of the redox treatment is not essential to provide a useful catalyst, one can, by subjecting the compositions of the invention to redox treatment after activation by oxidation, some change in selectivity, usually small, can be achieved. .

Therefore, when it is economically justified or when a slight change in selectivity is required, the redox treatment can be used.

It is not known why the crystalline compositions of the invention exhibit unexpected properties, for example why their selectivity with dimethyl ether, in the polymerization of ethylene and in the conversion of synthesis gas, is markedly different from that which this is obtained with a ZSM-5 zeolite. It is possible to imagine that ruthenium is part of the three-dimensional crystal lattice and that, in a way that is not yet known, it provides catalytic properties that ZSM-5 zeolites do not exhibit, even when they have exchanged with ruthenium or when physically mixed with ruthenium oxide.

The introduction of these same metals by ion exchange into a crystalline aluminosilicate does not ensure the same catalytic activity, which is an argument for the theory that ruthenium cations are part of the crystal structure of the present compositions and influence, in these positions, the catalytic properties of these crystalline aluminosilicates.

In the preparation of the crystalline compositions of the invention, the source of silica can be any of those which are commonly envisaged for the synthesis of zeolites such as solid silica powder, silicic acid, colloidal silica or silica. dissolved. A preferred source of silica is the product marketed under the name "Cab-O-Sil" by Cabot Co.

The alkali metal hydroxide is sodium hydroxide, potassium hydroxide or a mixture thereof.

In the preparation of the reaction mixture, ruthenium salts such as chloride, nitrate and the like can usefully be employed, for example ruthenium trichloride or tetrachloride, ruthenium nitrate, ruthenium acid sulfite H etc.

The valence of the ruthenium salt in the raw material can influence the catalytic properties of the final composition, despite the valence state of this metal in the catalytic composition.

The reason is not known, but it has been observed that when crystalline ruthenium aluminosilicate is prepared starting from a salt of Ru + 2, the catalytic properties are notably different from those of a ruthenium aluminosilicate prepared in starting from a salt of Ru + 5.

When the catalytic properties of the particular crystalline compositions described are evaluated without calcining them, they are inactive, possibly because the intracrystalline free space is occupied by organic cations from the forming solution. However, they can be activated by heat treatment using known techniques, for example by heating in an inert atmosphere or in air between 200 and 9000C approximately, for 1 to 60 hours. One can then operate an ion exchange with ammonium salts and, then, a heat treatment between 200 and 9000C approximately, if desired.

The crystalline composition can be used in the form of an alkali metal, for example the sodium form, in the ammonium form, in the hydrogen form or in other form with a monovalent or polyvalent cation. Preferably, the ammonium or hydrogen form is used. They can also be used in close association with hydrogenation constituents such as tungsten, vanadium, copper, molybdenum, rhenium, iron, nickel, cobalt, chromium, manganese or a noble metal such as than platinum or palladium, when it comes to providing a hydrogenation-dehydrogenation function. This constituent can be introduced into the composition by exchange, impregnation or intimate physical mixing. The catalyst can be impregnated with this constituent, for example, in the case of platinum, by treating the crystalline composition with an ion containing platinum. Thus, suitable platinum compounds are chloroplatinic acid, platinous chloride and various compounds containing ammine-platinum complexes.

The catalyst, when used as an adsorbent or as a catalyst in one of the above processes, can be heat treated as indicated above.

In members of the present family of crystal compositions, the originally associated cations can be replaced by a wide variety of other cations according to well known techniques. Typical replacement cations include hydrogen, ammonium, and metal cations as well as mixtures thereof. Among the replacement metal cations, particular preference is given to cations of metals such as rare earth metals, manganese, lithium and calcium, as well as metals of group IIB of the Periodic Table, for example zinc , and group VIII of the Classification
Periodic, eg nickel. These replacement cations fall within the definition of R in the formula used here to define the composition of the invention.

Typical ion exchange techniques involve contacting members of the aluminosilicate family with a salt solution of the desired replacement cation (s).

Although a wide variety of salts can be used, particular preference is given to chlorides, nitrates and sulfates.

Representative ion exchange techniques are described in a wide variety of patents, including
US 3,140,249, 3,140,251 and 3,140,253.

After contact with the salt solution of the desired replacement cation, the crystalline compositions are preferably washed with water and dried at a temperature varying from 65 to 3150C approximately, then heat treated as described above.

Regardless of the sodium substituting cations in the synthesized form of the catalyst, the spatial arrangement of the atoms which form the fundamental crystal lattices in any given composition of the invention remains virtually unchanged when sodium or other alkali metal is replaced as described. , as determined by recording an X-ray diffraction pattern of the powder of the material which has undergone the ion exchange. For example, the x-ray diffraction pattern of several exchanged compositions reveals a configuration substantially similar to that of zeolite.
ZSM-5.

The compositions prepared according to the invention are of a wide variety of particle sizes. Generally, the particles may be in the form of a powder, a granule or a molded product such as an extrudate having a particle size of less than 13 mm and greater than 0.15 mm. In cases where the catalyst is molded, for example by extrusion, the composition can be extruded before drying or it can be completely or partially dried and then extruded.

In the case of many catalysts, it is desired to incorporate the composition of the invention with another material resistant to the temperatures and other conditions applied in organic conversion processes. These materials include active and inactive materials and synthetic or natural crystalline compositions, as well as inorganic materials such as clays, silica and / or metal oxides. The latter can be of natural origin or in the form of gelatinous precipitates or gels comprising mixtures of silica and metal oxides. The use of a material in conjunction with the present catalyst tends to improve the conversion and / or the selectivity of the catalyst in certain organic conversion processes. Inactive materials preferably serve as diluents to control the degree of conversion in a given process. so that products can be obtained economically and in an orderly fashion without using other means to control the reaction rate. Normally, zeolites are incorporated into natural clays, for example bentonite and kaolin, to improve the crush resistance of the catalyst under commercial working conditions. These materials, i.e. clays, oxides etc ... play the roll of binders for the catalyst. It is desirable to obtain a catalyst having good crush resistance, since in a chemical process the catalyst is often subjected to handling or use which tends to break it up into powdery materials which cause inconvenience in the process. treatment. These clay binders are used to improve the crush resistance of the catalyst.

In addition to the above materials, the catalyst may include a porous matrix such as silica-alumina, silica-magnesia, silica-zirconia, silica-thorium oxide, silica-beryllium oxide, silica-beryllium oxide. titanium, as well as ternary compositions such as silica-alumina-thorium oxide, silica-alumina, zirconia, silica-alumina-magnesia and silica-magnesia-zirconia.

The gangue can be in the form of a cogel.

The following examples are presented as particular embodiments of the invention; they show some of the original characteristics of the crystalline compositions according to the invention and should not be considered as limiting it.

Example I
A number of ruthenium aluminosilicates are prepared.

To prepare a sodium silicate solution (A) containing less than 100 ppm aluminum (relative to silica), 80.0 g of high purity silica ("Cab-O-Sil") is dissolved in a boiling solution. 600 ml of water and 55 g of an aqueous solution of
50 to 52 S NaOH. A second solution (B) is prepared containing 85 g of Nazi, 33 g of tetrapropylammonium bromide (TPA-Br), 8.6 g of aluminum sulfate (A12 (s04) 3.18H20) , 19 g of concentrated sulfuric acid and 400 ml of water. The two solutions being at room temperature, solution B is slowly added to the sodium silicate with stirring. When the addition is complete, the pH is 9.2; it is adjusted to 8.5 by means of sulfuric acid.

To the above silicate mixture, with stirring, a third solution (C) is added comprising 25 ml of ruthenium acid sulphite containing 40 g of Ru per liter. The whole mixture is placed in a 2000 ml polypropylene flask partially immersed in an oil bath at 1200C. A reflux condenser is attached to the flask. After 10 days, the flask is removed from the oil bath and cooled. The solid is washed several times by decantation, it is collected on a filter, washed with deionized water and dried at 115 ° C.; 84.0 g of final product are obtained. The dried material is analyzed by X-rays and it has the same diagram which is published for an aluminosilicate of type
ZSM-5 (zeolite). The ruthenium content of the dried sample is 0.98% and the aluminum content 0.75%.

A portion of the dried sample is calcined at 5380C for 16 hours. The calcined material is mixed with a solution of 60 g of NH4Cl in 300 ml of water and refluxed for 4 hours.

After washing, the exchange is repeated a second time for 16 hours. The material is filtered, washed and dried; 25.2 g of solid which has undergone exchange with ammonium ion are obtained, having a ruthenium content of 1.5 X and an aluminum content of 0.80 X. Before the test, the ammonium form is converted in shape
H by heating in air to 538 C.

A portion of the exchanged material is stirred with a solution of 10.0 g of LiCl in 92 ml of water. After heating at reflux for 3 hours, the mixture is cooled and the solid washed with water. The solid is treated a second time with a similar lithium chloride solution at reflux for 18 hours. The solid recovered is washed with deionized water until no more chloride is detected by means of silver nitrate. The washed material, which has undergone the exchange with Li, is dried at 1200C.

All samples of these crystalline ruthenium aluminosilicates show the pattern of ZSM-5 zeolites, although the ion-exchanged versions show some small lattice distance shifts and relative intensity variation compared to the crystalline material drawn. of the reaction mixture. Additional variations may occur, but small, depending on the metal / silica ratio of the sample in question or whether or not it has been subjected to chemical treatment.

Example II
The catalytic properties of the ruthenium aluminosilicate compositions prepared in Example I were evaluated in a series of tests using feed materials such as dimethyl ether (DME), ethylene, methanol and gas. synthesis (mixture of CO and H2) and compared to zeolites
ZSM-5.

1. Test data with DME
Data for the H + and Li + forms of the composition of Example I are shown, together with comparative data for a SiO 2 / Al 2 O 3 catalyst (ZSM-5). The feed is 1.5 g of
DME / g of catalyst / h at a relative pressure of 41 kPa.

Catalyst Ex. I Ex. I ZSM-5
SiO2Al2O3 / Ru2O3 SiO2 / Al2O3 / Ru2O3 SiO2 / Al2O3
H + Li + ion form
Temperature, OC 420 500 420 500 420 500
HC yield,% (C) 100 100 0 <1 100 100
Selectivity for HC, Dó (C)
C1 4 15 - - 4 3
C2 O 0 - - 0 5
C3 16 20 - - 13 22
C4 18 32 - - 21 23
C5 + 30 5 - - 32 22
Aromatics 32 28 - - 30 25
At 5000C, ruthenium in combination with aluminum gives a greater selectivity than H-ZSM-5 for hydrocarbons in
C4 and below.

2. Test data with ethylene
All the catalysts are tested in the H + form at 1.5 g of
C2H4 / g of catalyst / h, at 4200C and at a relative pressure of 41 kPa.

Catalyst Example I ZSM-5
Efficiency Ó (C) 97 96
Selectivity Ó (C)
C1 2 0
CH 1 0
C3 26 18
C4 22 22
C5 + 22 34
Aromatics 27 26
The ethylene test data did not significantly distinguish the ruthenium-containing catalyst.

3. Test data with methanol
Not determined.

4. Test data with gas
A 2/1 H2 / C0 feed is used, at a relative pressure of 5.1 MPa and at a relative flow rate of about 60 h 1, at 350 C for the Li + form and at 3000C for the H + form of the composition of example I.

H + (b) Li + ion form
HC yield,% (C) 13 8
Selectivity for HC, ea (C)
C1 70 9
C2 30 23
C3 0 2
t4 O 16
fa) C + 0 50
Aromatics OO
Oxidation product yield, DA (C) 8 3
Selectivity for oxidation products, MD (C)
CO2 100 63
DME 0 37
- a) We estimate C7 maximum
- b) Treated with hydrogen at 350 ° C. and at a relative pressure of 5.1 MPa for 18 hours before treatment.

The above data shows the remarkable property possessed by the lithium form of the SiO2 / Al203 / Ru203 catalyst, of forming low molecular weight hydrocarbons with relatively low selectivity for H4. Much has been said about the conversion of synthesis gas to hydrocarbons using Ru catalysts supported by silica or alumina. One cannot make exact comparisons, given the different working conditions, but, obviously, at 350 C, one must expect, with these catalysts, an extremely important formation of CH4. TJ Huang and WOHaa "Second Chemical Conference of the North American Continent", Inorgan
Division, Item No. 218, August 24-29, 1980 (Las Vegas) reported that physical mixtures of Siû2 / A1203 (ZSM-5) and ruthenium oxide give high yields of aromatic hydrocarbons from synthesis gas. The use of Li + is not mentioned. Although the above test conditions are not exactly the same, it is evident that the catalyst of Example I differs from the catalyst of Huang and Haag, since the catalyst of the invention does not give aromatics. The
Table V of the cited article indicates a selectivity for aromatics of 14.7% at 294 C and of 8.2% at 328 C. Regarding the selectivity for CH4, Table V indicates 61.3% at 328. C. The H + version of the present invention exhibits a high selectivity for CH4, 70% at 300 C, while the version
Li + gives a low yield of methane (9%) at 350 C.

Claims (10)

1.- Crystalline composition of ruthenium aluminosilicate characterized in that the molar ratios of oxides are as follows: (0.150) R20: (0.05 to 20) Ru20: (0.05 to 10) Al203: 1005i02: (0 to200 ) H20: n m R being a tetraalkylammonium, hydrogen, alkali metal, metal, ammonium ion or a mixture thereof, n being the valence of R and m the valence of ruthenium. 2.- Composition according to claim 1, characterized in that m = +2 or +3. 3.- Composition according to one of claims 1 and 2, characterized in that it has undergone ion exchange with ammonium, hydrogen, a rare earth metal, a group VI metal, a group VIII metal, lithium or zinc. 4. A composition according to claim 3, characterized in that the replacement cation is an ammonium or hydrogen cation. 5.- Composition obtained when the composition according to one of claims 1 to 4 is thermally treated at a temperature of approximately 200 to 9000C. 6.- Composition according to one of claims 1 to 5, characterized in that it has been activated by heating in an atmosphere containing molecular oxygen. 7. A process for preparing a composition according to claim 1, characterized by the following steps: preparing a mixture containing a Ru salt, an aluminum salt, a tetraalkylammonium compound, an alkali metal hydroxide, silica and water, the composition of the mixture in molar oxide ratios falling within the following ranges: OH- / Si02 0.05 to 3 + + A) A +) 0.01 to 1 H20 / 0H 10 to 800 SiO2 / Ru2 / mO 5 to 2000 Si02 / A1203 10 to 2000 in which Q + is a quaternary ammonium ion and A + an alkali metal ion, the mixture is maintained at a temperature of about 50 to 2500C; until 8 th OLJ 'crystals of the silicate form and the silicate crystals form. 'the crystals are separated and recovered. 8. Application of the composition according to one of claims 1 to 6, to the conversion of oxygenates into hydrocarbons. 9. Application of the composition according to one of claims 1 to 6, to the polymerization of ethylene, or of ethylene and other monomers. 10. Application of the compositions according to one of claims 1 to 6, to the conversion of a synthesis gas, comprising hydrogen and carbon monoxide, into hydrocarbons and / or oxygenated compounds.