MXPA98005041A - Method of preparation of amoxidation catalysts for fluidized bed reactor or a lechome - Google Patents

Abstract

The present invention relates to a method for the preparation of catalysts comprising mixed oxides based on vanadium, antimony and optionally tin and / or titanium and / or iron and / or other metals, deposited on a support as well as their use by ammoxidation of alkanes. The method of preparation of a catalyst defined above is characterized in that it comprises: impregnation of a solid support of a peroxide with the aid of a solution in at least one saturated alcohol of respective vanadium, antimony and optionally tin and / or titanium compounds and iron and / or other metals, the contact of the impregnated solid support obtained, with an aqueous buffer solution with a pH comprised between 6 and 8, the separation of the solid and its drying, the calcination of the solid in two stages, first at a temperature of 300 ° C, and then at a temperature of 400 ° C to 800 ° C. Such catalysts are adapted for use in a fluidized bed or a moving bed

Description

METHOD OF PREPARATION OF AMOXIDATION CATALYSTS FOR FLUID BED REACTOR OR A MOBILE BED DESCRIPTION OF THE INVENTION The present invention relates to a method for the preparation of mixed oxides based on vanadium, antimony and, possibly, tin and / or titanium and / or iron and / or other metals, deposited on a support for use as catalysts. for the ammoxidation of al cano s. Certain mixed oxides of vanadium and of antimony or of vanadium, of antimony and of other metals are known compounds that have been described, among the names of other mixed oxides, in the patent FR-A-2 072 334. In the patent US 5 008 427 discloses a method of ammoxidation of propane or butane, in the presence of a catalyst which can comprise, in particular, the oxides of vanadium, of antimony and of iron or titanium or of chromium or of gallium or tin; as well as possibly other metals. Such catalysts present the essential characteristic of having calcined states at a temperature equal to or higher than 780 ° C. Similarly, in patent EP-A-0 558 427, a method of ammoniaxidation of alkanes, catalyzed by the mixed oxides of vanadium, antimony, iron and / or gallium and / or indium was described. The preparation of such mixed oxides is done through the mixture of aqueous suspensions of compounds of different metals, heating under stirring, then evaporation of the water, drying and calcination .. Such patents do present the particular indication in relation to the reactor technology associated with However, for the type of reaction represented by the ammoxidation of alkanes, it has been proved that the use of a fluidized bed or moving bed reactor is more advantageous. the exo-ermicity of the reactions involved in the ammoxidation of alkanes, the possibility of putting into practice, on the industrial scale, one or more fixed-bed alkanes (react It seems unrealistic, really excluded, particularly if we want to expect high productivity. To effectively eliminate the calories released, one would have to use a large-sized tubular reactor or a whole battery of tubular reactors, one that is redhibitory of the investment plan. In relation to the fixed bed reactor, fluidized bed or mobile reactors have a larger capacity to evacuate calories, and appear to be better adapted to the ammoxidation reaction of the alkanes. The best capacity to transmit heat allows to consider a productivity gain by increasing the amount of alkane in the feed mixture. Such an operation can be considered in the case of a fixed bed reactor, since the limitations at the level of heat transfer (manifested by the existence of a hot spot in the reactor) impose the use of relatively weak contents in alkane , to avoid in this way any problem of explosivity or flammability of the gas mixture. The present invention relates to a method of preparing a catalyst for a fluidized bed or moving bed reactor comprising an active phase of the general empirical formula (I): V Sba Snb Tic Fed Ee 0X (I) where: E represents an element that can provide an oxide of rutile structure or an element that, associated with V, Sb, Sn, Ti, Fe and / or aer element E, can provide a rutile or trirutile structure phase or a routine solid solution. a represents a whole or fractional name equal to or greater than 0.5 - b, c, d and e represent independently of each other a whole or fractional number of the 0 to 100. x represents a whole or fractional number determined by the degree of oxidation of the other elements, and a solid support of oxide type, such method is characterized in that it comprises: - impregnation of the solid support by a solution at least in one saturated alcohol of respective vanadium compounds, of antimony and possibly of tin and / or of titanium and / or of iron and / or element E, the contacting of the impregnated solid support obtained, with an aqueous buffer solution of pH comprised between 6 and 8, - the separation of solid and its drying, the calcination of the solid in two stages, first at a temperature of 300 ° C to 350 ° C, and then at a temperature of 400 ° C to 800 ° C. The E elements are selected in particular from germanium, manganese, ruthenium, niobium, tantalum, gallium, chromium, rhodium, nickel, molybdenum, aluminum, thorium, calcium, tungsten and magnesium. Various elements E can be present in the formula (I) and in the present document, the expression of the element E covers one or more elements E. The vanadium, antimony, tin, titanium, iron and element compounds E established in the method must be soluble in a saturated alcohol or a mixture of saturated alcohols. In the present document, a compound is considered to be soluble until its measured solubility is 25 ° C and at least 5 grams per liter of saturated alcohol or water. Such compounds can be introduced together; first they can also be placed separately in solution in an alcohol, and the different alcoholic solutions obtained in this way are immediately mixed with each other. Generally, but not limitatively, an alcoholic solution is prepared by dissolving the different compounds, without intermediate preparation of solutions of each of the compounds of vanadium, antimony and, if necessary, tin, titanium, iron and the element E Examples of vanadium-soluble compounds are vanadyl acetylacetonate, vanadyl trichloride, vanadium trifluoride, vanadium tetrafluoride, vanadium pentafluoride, vanadium tribromide, vanadium dichloride, vanadium trichloride. , vanadium tetrachloride and vanadium triodide. Examples of soluble antimony compounds include antimony pentachloride, antimony trichloride, antimony tribromide, antimony trifluoride, antimony trioxide, antimony trioxide and antimony hydride.

As examples of the soluble compounds of tin, we can mention stannic chloride, stannous chloride and stannous bromide. As examples of soluble titanium compounds, mention may be made of titanium dichloride, titanium tetrachloride, titanium trichloride, titanium tribromide, titanium tetrabromide, titanium tetrachloride and titanium dioxide. As examples of soluble iron compounds, we can mention iron dichloride, iron trichloride, iron dibromide, iron tribromide, iron diiodide, ferrous nitrate, ferrous sulfate, ferric sulfate, ferrous thiosulfate , "ferric formate, ferric acetate, ferric acetylacetonate, ferric benzoate, ferric oleate, ferrous lactate and ferric lactate. The saturated alcohols used in the method of the invention are more particularly the alkanols and the cycloalkane is. Preferably the alkanols and cycloalkane are used where the boiling temperature is not very high, in order to facilitate separation or recycling operations by distillation or evaporation. Thus, alkanols having 1 to 6 carbon atoms, such as methanol, ethanol, n-propanol, propanol-2, n-butanol, butanol-2, tertiary butyl ether, are preferred. 1, pentanols and hexanols and cyclohexane 1. The solid support is an oxide such as an aluminum, a silicon, a silicon dioxide, a zirconia, a zirconium, a mixed oxide of cerium and zirconium, a magnesia , a titanium oxide, a niobium oxide and a lanthanum oxide. The size of the solid support particles - generally is from 10 μm to 1000 μm and preferably from 20 μm to 300 μm. Another important feature of the solid support is its ability to be impregnated by a solution of metal compounds of the active phase. In this way, supports having a total pore volume of at least 0.1 cm3 / g and preferably of at least 0.15 cm3 / g will be used. The fluidization quality of the catalytic bed can also depend on other parameters, such as, in particular, the density of the support, the type of life of the support and the gaseous capacity. The desired fluidization of the catalyst of the invention, in particular for the use in ammoxidation of the alkanes, will be carried out in an optimal way by the experienced man taking into account the various parameters. Among the solid supports having the characteristics indicated above, it is preferred to use the silicones in the method according to the invention. The impregnation of the solid support by the alcoholic solution of the incoming metal compounds within the composition of the active phase of the formula (I) is carried out by establishing a volume of alcoholic solution less than or equal to the total porous volume of the support, which it will represent at least 50% of the total pore volume. The duration of the impregnation phase is not critical; it can simply be varied in practice according to the mode of the mixture of the support and of the solution that has been chosen. The impregnated solid support is then contacted with an aqueous buffer solution having a pH comprised between 6 and 8, and preferably between 6.5 and 7.5; such an aqueous buffer solution is preferably in an aqueous solution of ammonium salt, which eventually includes ammonia. The sodium salt most preferably used is an ammonium carboxylate (ie, acetate, citrate, tartrate), ammonium oxalate, ammonium carbonate and ammonium hydrogen phosphate, allow a pH of about 7, possibly in presence of ammonia. In this way, ammonium acetate / ammonia buffer solutions are particularly convenient. The volume of the buffer solution brought into contact with the impregnated support is equal to or greater than the total porous volume of the support, and is preferably greater than the total pore volume of the second solution. The solid obtained is separated from the liquid by the means usually used for this operation, that is, by filtration or centrifugation. The solid is then dried at a temperature that allows water to be removed and depends on the pressure under which it is operated. If operating under atmospheric pressure, the drying temperature will advantageously be from 100 ° C to 200 ° C, preferably from 110 ° C to 180 ° C. If operating under a pressure below atmospheric pressure, the drying temperature may be more feasible, generally equal to or greater than 50 ° C. The drying duration can vary widely according to the chosen temperature. This will be generally determined in order to eliminate most of the impregnation water. The duration of drying often varies from a few minutes to a few hours. The calcination of the solid dried in this way is carried out in a furnace at a temperature of 300 ° C to 350 ° C, then at a temperature of 400 ° C to 800 ° C, and then preferably between 500 ° C and 750 ° C for the second stage, and during the durations that vary in an indicative manner from a few minutes to several hours, more usually from 30 minutes to 20 hours. In the final catalyst, the weight ratio between the active phase of the formula (I) and the total catalyst is generally from 5 to 50%. Among the mixed oxides of the active phase of formula (I) defined above, those by which: E represents one or more elements selected from nickel, gallium, aluminum and niobium-a represents an integer or fractional number equal to or less than 100 and preferably comprises between 0.5 and 50. b, c, d and e represent, independently from each other, a whole or fractional number from 0 to 50, at least one of these symbols is greater than 0 and preferably equal or greater than 0.5. - x represents an integer or fractional number determined by the degree of oxidation of the other elements. The subject of the present invention is also a method for the ammoxidation of alkanes in the vapor phase in a fluidized bed or moving bed reactor, in the presence of a catalyst comprising an active phase of the general empirical formula (I): V Sba Snb Tic Fed Ee Ox (I) where: E represents an element that can provide an oxide of rutile structure or an element that, associated with V, Sb, Sn, Ti, Fe and / or to another element E, it can provide a rutile or trirutylated structure phase or a solid solution of rutile structure. - a represents an integer or fractional number equal to or greater than 0.5. b, c, d and e represent, independently of each other, an integer or fractional number from 0 to 100. - x represents an integer or fractional number determined by the degree of oxidation of the other elements, and a solid support of oxide type, such catalyst method is prepared by the method described above comprising: impregnation of the solid support by a solution in at least one saturated alcohol of respective vanadium compounds, antimony and optionally tin and / or titanium and / or iron and / or element E, - the contacting of the impregnated solid support obtained, with an aqueous buffer solution pH comprised between 6 and 8, - the separation of the solid and its drying, the calcination of the solid in two stages, first to a temperature of 300 ° C to 350 ° C, then at a temperature of 400 ° C to 800 ° C. According to the present invention, alkanes having from 3 to 12 carbon atoms per molecule are reacted in vapor phase with ammonia and oxygen in the presence of a catalyst wherein the composition and preparation are indicated in the description preceding. It is understood that, within the framework of the present method, diluent gases, inert under reaction conditions such as helium, nitrogen and argon, can be used. Similarly, water vapor can be adjusted to the reaction gas mixture to a large extent. Reactive gas (alkane, ammonia, oxygen) can also be diluted by an inert diluent and / or water vapor. In this conjunction, the volumetric content in water vapor can vary greatly, particularly from 0 to 50%, and preferably between 3 and 30%. For a good application of the method according to the invention, the volume amount of reactive gas will be at least 3% and preferably at least 20%.

Within the reactive gas, the respective amounts of vulcan in alkane, ammonia and oxygen can vary widely. The amount of alkane in the reactive gas is preferably comprised between 5 and 70%. The amount of ammonia is preferably comprised between 3 and 45%. As far as propane is concerned, a mixture will be obtained that essentially comprises acrylic and tri lo. The acr ino 1 i tri lo is an intermediary industrially produced on a large scale. As for isobutane, it will be obtained essentially from methacrylonitrile. The method according to the invention is more particularly suited to the ammoxidation of propane. If the established alkane can be of technical quality, it will not comprise significant amounts of compounds with ethylenic unsaturation. In this way, the propane retained will generally contain only minor amounts of propylene, that is, less than 10%. As indicated above, the method according to the invention is carried out in the form of a vapor phase reaction, in a fluidized bed or moving bed reactor. The method can be conducted continuously or discontinuously. The reaction temperature generally comprises between 300 ° C and 500 ° C and, preferably, between 400 ° C and 500 ° C. The total pressure of the reaction mixture may be greater than or equal to atmospheric pressure. Such atmospheric pressure comprises between 1 and 6 bar and, preferably, between 1 and 4 bar. The hourly volumetric speed usually comprises between 100 and 36000 h "1, this depends on the gaseous efficiency, but also on other parameters of the reaction, the volumetric hourly speed is preferably between 200 and 20,000 h1.

Volumetric speed is defined as the report of gaseous volume tot to the volume of the cat at the hour / hour. It is understood that the person skilled in the art will be the one who finds a midpoint between the temperature, the amount of gas, the precise nature of the catalyst in use and the various other parameters of the COMPTE-TENU reaction of its production objectives. The products of the reaction can be recovered in the affluent gases by any appropriate means. That is, the affluent gases can pass in a condenser containing dilute sulfuric acid to neutralize the unconverted ammonia. The gas can then be passed to a cooled absorbent colony to condense acrylonitrile, acetonitrile, and hydrocyanic acid; the non-condensed vapors contain mainly unconverted propane, propylene, light hydrocarbons and, if necessary, C02. The acrylonitrile and the hydrocyanic acid of the acetonitrile can then be distilled off, then the acrylonitrile-hydrocyanic acid mixture recovered in order to separate the acrylonitrile from the hydrocyanic acid. The following examples illustrate the present invention: EXAMPLES OF PREPARATION OF MIXED OXIDES. EXAMPLE 1 Preparation of the catalyst (A) according to the invention comprising a mixed oxide of empirical formula: V Sb5 Sn 5 Ox and a silica support It is impregnated dry (ie with a volume of solution less than or equal to the volume porous of the support) 13 g of silica having a particle size of 30 to 100 μm, a BET specific surface of 320 m2 / g, a porous volume of 1.2 cm3 / g and a density of 0.36, with 15.6 cm3 of a solution ethanolic containing 2.15 g of SnCl4, 0.437 g of vanadyl acetylacetonate and 2.46 g of SbCl5. The impregnated solid is poured into 150 cm 3 of an aqueous solution containing ammonium acetate / ammonia buffer (65/15 g / 1) and having a pH of 7.0. The solid is then separated by centrifugation, dried at 120 ° C for 24 hours. Then it is burned for an hour to 350 ° C, and then for 3h at 700 ° C. The catalyst obtained in this way comprises 17% by weight of mixed oxide V Sb5 Sn5 Ox and 83% by weight of silica support, on a specific surface area of 280 m2 / g and a density of 0.43. EXAMPLE 2 Preparation of the catalyst (B) according to the invention comprising a mixed oxide of the empirical formula: V Sb5 Sn 5 Ox and an alumina support It is impregnated dry (ie with a volume of solution less than or equal to the porous volume of the support) 39 g of alumina having a particle size of 20 to 90 μm, a BET specific surface area of 180 m2 / g, a porous volume of 0.4 cm3 / g and a density of 0.74, with 15.6 cm3 of an atanolic solution containing 2.15 g of SnCl-1, 0.437 g of vanadyl acetylacetonate and 2.46 g of SbCl 5. The impregnated solid is poured into 150 cm 3 of an aqueous solution containing ammonium acetate / ammonia buffer (65/15 g / 1) and having a pH of 7.0. The solid is then separated by centrifugation, dried at 120 ° C for 24 hours. It is then calcined for one hour at 350 ° C, and then for 3 h at 700 ° C. The catalyst obtained in this way comprises 6.5% by weight of mixed oxide V Sb5 Sn5 Ox and 93.5% by weight of the alumina support, on a specific surface area of 150 m2 / g and a density of 0.87. EXAMPLES 3 TO 5 - Preparation of catalysts (C), (D) and (E) according to the invention comprising mixed oxides of empirical formulas: V Sb2, 5 Sn2.5 Ox V Sb5 Sn5 Sn5 Ox V Sb2, 5 Sn2, 5 Ox and a solid support When using the operating mode and the reagents described in Example 1, and if necessary, adapting the quantities of such reagents, the following catalysts are prepared: - Catalyst (C) it comprises 17% by weight of mixed oxide V Sb2.5 Sn2 / 5 Ox and 83% by weight of silica support and having a specific surface area of 195 2 (g); - Catalyst (D) comprising 23% by weight of mixed oxide V Sb5 Sn5 0X and 77% by weight of silica support and having a specific surface area of 235 m2 / g; - Catalyst (E) comprising '23% by weight of mixed oxide V Sb2.5 Sn2.5 Ox and 77% by weight of silica support and having a specific surface area of 250 m2 / g. GENERAL OPERATING MODE OF AMOXIDATION TESTS The evaluation of the catalytic results of the catalysts (A) and (B) was carried out in a glass fluid bed reactor, with an internal diameter of 1.8 cm and a height of 20 cm, equipped with an axial thermocouple, so that the temperature can be measured along the catalytic bed. Approximately 15 cm3 of catalyst are used for each amoxidation test; because of the density difference between silica and alumina, such a volume corresponds, for example, 6.4 g for the catalyst (A) and 13.0 g for the catalyst (B). The reaction mixture used in the series of tests carried out in the fluidized glass reactor to the following volume composition: C3H8 / NH3 /? 2 / He = 25/10/20/45. The total pressure of the reaction mixture is 1.3 bar for each example. The total gas quantity is ordered to obtain different contact times; the contact times are calculated by considering the volume of the fluidized catalytic bed (15 cm3) and the gaseous quantity under the standard conditions of temperature and pressure. The exposed contact times are as follows: 5s (total capacity: 180cm3 / min), lOs (total capacity: 90cm3 / min) and 15s (total capacity: 60cm3 / min). The corresponding linear velocities of the gas (vacuum frame speed), calculated by the standard conditions of temperature and pressure and taking into account the presence of the axial thermocouple in the reactor, are 105 cm / min, 52 cm / min and 35 cm / min.

The principle of the ammoxidation test is as follows: - The catalyst is placed at a temperature Ti, for example 310 ° C, and after 30 minutes of stabilization at the temperature Ti, the composition of the mixture exiting the reactor is determined by graphite or graphite in gas phase. The conversion percentages and the selectivities obtained in the catalyst examined at the input temperature Ti are calculated by the ratios of the type: conversion of propane (in mol%) = trans propane formed / propane introduced selectivity in acr ino 1 i tri lo ( in moles%) = propane transformed into acr ino 1 i tri lo / converted propane. - The catalyst is then passed from 310 to 550 ° C by an increase of 20 ° C and the conversion percentages and selectivities are determined during 40 minutes. In the examples of ammoxidation discussed here, the following conventions are used: Time = reaction temperature TTC3H8 = conversion of propane SACN = selectivity in acrylonitrile SACN --- C3H6 = selectivity in acrylonitrile and propylene SAMMOX = selectivity in acetonitrile, in hydrocyanic acid and in other byproducts of ammoxidation. te (s) = contact times in seconds. The complement to 100% of the selections corresponds to the formation of CO and C02, as well as possibly methane, ethane and ethylene.

EXAMPLES OF PROPANE AMOXIDATION EXAMPLES 6 TO 10 The ammoxidation of the propane is carried out, as described above, using catalysts A, B, C, D and E according to the invention. It can be specified, as an indication for catalyst A, that the minimum fluidization capacity is 9-10 cm3 / min (frame speed at vacuum of 6 cm / min). The expansion of the fluidized bed is linear up to 60-70 cm3 / min (35-40 cm / min). The height of the catalytic bed evolves from . 8 cm (dense non-fluidized bed for capacities below the minimum fluidization capacity) to 16.5 cm. For capacities greater than 70 cm3 / min, there is no further variation in the height of the catalytic bed.

The temperature conditions and the results are listed in Table 1 below Table 1

Claims (19)

RE IVIND I CAC IONE S

1. A method of preparing a catalyst for a fluidized bed or moving bed reactor comprising an active phase of the general empirical formula (I): V Sba Snb Tic Fed Ee 0X (I) in which: E represents an element that can providing an oxide of rutile structure or an element which, associated with V, Sb, Sn, Ti, Fe and / or another element E, can provide a phase of rutila or triutila structure or a solid solution of rutila structure. - a represents an integer or fractional number equal to or greater than 0.5, - - b, c, d and e represent, independently of each other, an integer or fractional number from 0 to 100, - x represents an integer or fractional number determined by the degree of oxidation of the other elements, and a solid support of oxide type, such method is characterized in that it comprises: the impregnation of the solid support by a solution in at least one saturated alcohol of respective compounds of vanadium, antimony and, if necessary, tin and / or titanium and / or iron and / or element E, the contacting of the impregnated solid support obtained, with an aqueous buffer solution with a pH comprised between 6 and 8, - the separation of the solid and its drying , the calcination of the solid in two stages, first at a temperature of 300 ° C to 350 ° C, and then at a temperature of 400 ° C to 800 ° C.

2. The method according to claim 1, characterized in that the solid support is an oxide such as an alumina, a silica, an ice-alumina, a zirconia, a cerina, a mixed oxide of cerium and zirconium, a magnesia, a titanium oxide, a niobium oxide and a lanthanum oxide.

3. The method according to one of claims 1 or 2, characterized in that the solid support has a particle size of 10 μm to 100 μm and preferably 20 μm to 300 μm.

4. The method according to one of claims 1 to 3, characterized in that the solid support has a porous volume of at least 0.1 cm3 / g and preferably at least 0.15 cm3 / g.

5. The method according to one of claims 1 to 4, characterized in that in the final catalyst, the weight ratio between the active phase of the formula (I) and the totality of such a catalyst is from 5 to 50%.

6. The method according to one of claims 1 to 5, characterized in that the solid vanadium compound is selected from vanadyl acetylacetonate, vanadyl trichloride, vanadium trifluoride, vanadium tetrafloride, vanadium pentafluoride, vanadium tribromide, vanadium dichloride, vanadium trichloride, vanadium tetrachloride and vanadium triodide.

7. The method according to one of claims 1 to 6, characterized in that the soluble antimony compound is selected from antimony pentachloride, antimony trichloride, antimony tribromide, antimony trifluoride, antimony triodide, antimony trioxide and antimony hydride.

8. The method according to one of claims 1 to 7, characterized in that the soluble tin compound is selected from the stannic chloride. the stannous chloride and the stannous bromide.

9. The method according to one of claims 1 to 8, characterized in that the titanium tetrachloride is selected from the titanium dichloride, titanium tetrachloride, titanium trichloride, titanium tribromide, titanium tetrabromide, the titanium tetrafloride and the titanium diode.

10. The method according to one of claims 1 to 9, characterized in that the soluble compound of the iron is selected from iron dichloride, iron trichloride, iron dibromide, iron tribromide, iron dioxide. , ferrous nitrate, ferrous sulfate, ferric sulfate, ferrous thiosulfate, ferric formate, ferric acetate, ferric acetylacetonate, ferric benzoate, ferric oleate, ferrous lactate and ferric lactate.

11. The method according to one of claims 1 to 10, characterized in that the saturated alcohol applied is selected from the alkanols and the cycloalkanes and preferably, the alkanols having from 1 to 6 carbon atoms, such as methanol , ethanol, n-propanol, propanol-2, n-butanol, butanol-2, thiobutanol, pentanols and hexanols and cyclohexane 1.

12. The method according to one of claims 1 to 3, characterized in that the impregnation of the solid support by the alcoholic solution of the incoming metal compounds in the composition of the active phase of the formula (I) is carried out by applying a volume of alcoholic solution less than or equal to the total porous volume of the support, such volume of the alcoholic solution preferably represents at least 50% of the total pore volume.

13. The method according to one of claims 1 to 12, characterized in that the impregnated solid support is contacted with an aqueous buffer solution of an ammonium salt, optionally comprising ammonia, the ammonium salt used, preferably being a carboxylate of ammonium, ammonium carbonate and hydrogenated ammonium.

14. The method according to one of claims 1 to 13, characterized in that the volume of the buffer solution brought into contact with the impregnated support is equal to or greater than the total porous volume of the support and is preferably greater than the total porous volume of the support.

15. The method according to one of claims 1 to 14, characterized in that the active phase corresponds to formula (I) in which: E represents one or more elements selected from nickel, gallium, aluminum and niobium - a represents an integer or fractional number equal to or less than 100 and preferably comprises between 0.5 and 50-b, c, d and e independently of each other a whole or fractional number from 0 to 50, at least one of the symbols is higher to 0 and preferably equal to or greater than 0.5 x represents an integer or fractional number determined by the degree of oxidation of the other elements

16. The method of ammoxidation of the alkanes in the vapor phase in a fluidized bed or moving bed reactor in the presence of a solid catalyst, characterized in that said catalyst is obtained by the method according to claims 1 to 15.

17. The method according to claim 16, characterized in that alkanes having from 3 to 12 carbon atoms per molecule, selected preferably from propane and isobutane, are reactivated in the vapor phase with ammonia and oxygen.

18. The method according to one of claims 16 or 17, characterized in that within the reactive gas, constituted by alkane, ammonia, oxygen, the volumetric ratio in alkane is preferably comprised between 5 and 70%, the volumetric ratio in ammonia is comprised preferably between 3 and 50% and the volume ratio in oxygen is preferably comprised between 3 and 45%.

19. The method according to one of claims 16 to 18, characterized in that the reaction temperature is between 300 ° C and 550 ° C and, preferably, between 400 ° C and 500 ° C.