CN1046292A - Ammoxidation of Alkanes and Its Catalysts - Google Patents

Abstract

Disclosed is the use of certain complex metal oxide catalysts containing V, Sb, W and certain optional elements with C₃-C₄Alkane and O₂And NH₃The alpha, beta-unsaturated nitrile and olefin are prepared by reaction.

Description

The present invention relates to the catalytic ammoxidation of C ₃ -C ₄ alkanes to generate α, β-unsaturated mononitriles. More importantly, the ammoxidation of propane to produce acrylonitrile and isobutane to produce methacrylonitrile, with the emphasis on the former.

Due to the large price difference between propylene and propane, there is an economic incentive to investigate a viable catalytic conversion of propane to acrylonitrile.

In Application No. 724,226, filed April 17, 1985, there is disclosed and claimed a class of catalysts comprising Sb and V in an atomic ratio Sb:V > 1, and at least one other cations and oxygen, and is supported on an inorganic oxide support that improves its catalytic activity. These catalysts are used for the reaction of alkanes with ammonia and oxygen to produce nitriles and olefins, especially for the production of acrylonitrile and propylene from propane.

In Application No. 049,252, filed May 15, 1987, a catalyst is disclosed and claimed which contains Sb and V in an atomic ratio of Sb:V>1. Among the preferred catalysts are those containing W together with phosphorus and an inorganic oxide support which improves its catalytic activity. These catalysts are used for the reaction of alkanes with ammonia and oxygen to produce nitriles and alkenes; especially the use of propane to produce acrylonitrile and propylene.

In the application case No. 047,949 submitted on May 8, 1987, the reaction of alkanes with oxygen and ammonia to form alkenes and α, β-unsaturated nitriles was disclosed, wherein V, Sb, W and a carrier were also used. A catalyst having an atomic ratio Sb:V greater than 1. Phosphorus is also advantageously present in these catalysts.

It is an object of the present invention to provide an improved process for the ammoxidation of alkanes to unsaturated mononitriles and the corresponding monoenes.

It is also an object of the present invention to provide novel catalysts for this reaction.

It is also an object of the present invention to provide an improved catalytic ammoxidation process for the production of unsaturated nitriles and alkenes from lower alkanes without the use of halogen promoters.

Other objects, aspects, features and advantages of the present invention will be clarified by the following disclosure and claims.

According to one aspect of the present invention, the method for preparing C ₃ -C ₄ α, β unsaturated mononitrile and C _{3 -C 4 monoene by catalytic reaction of C 3 -C 4 alkane} with ammonia and oxygen provided, Thereby reached each object of the present invention, described method is that aforesaid reactant has a kind of composite metal oxide catalyst of following experimental formula with its element and relevant ratio in a reaction zone and carries out catalytic contact reaction:

V _l Sb _m A _a H _b C _c T _t O _x

Wherein A is one or more of W, Sn, Mo, B, P and Ge;

H is one or more of Fe, Co, Ni, Cr, Pb, Mn, Zn, Se, Te, Ga, Zr, In and As;

C is one or more of alkali metals and Tl;

T is one or more of Ca, Sr, Mg, and Ba;

Where m is 0.01-1; a is 0.2-10; b is 0-10; c is 0-1; t is 0-10; (a+b+c+t): (l+m) ratio is 0.1 -6; for each atom of V, the amount of Mo atoms present does not exceed 2; where x is determined by the oxidation state of other elements; and where the average valence of Sb is higher than +3, and the average valence of V is low at +5; wherein A includes at least 0.2 atoms of W calculated as V per atom; and said catalyst contains a carrier/diluent material selected from silica-alumina and alumina and containing 20- 100% aluminum oxide by weight.

The nitrile products of the present invention contain a C to C double bond and a nitrile group. The desired alkene product contains one double bond and has the same number of C atoms as the starting alkane.

In the above catalysts, A generally includes W having a V of at least 0.4 atoms per atom. In particularly suitable catalysts, A includes P having a V of at least 0.1, usually at least 0.5 atoms per atom.

Typically, the carrier/diluent will contain 50-100% alumina, more usually 60-100% by weight alumina.

It should be noted that the ammoxidation reaction of the present invention is carried out in the substantial absence of halogens or sulfur or their compounds. Preferably no halides or halogens are used at any stage of catalyst preparation. Furthermore, the catalyst of the present invention does not contain uranium.

The process of the invention is particularly suitable for the ammoxidation of propane and isobutane.

According to the present invention, the aforementioned catalyst preparation conditions are such that the average oxidation state of V in the final composition is lower than 5. One of the methods for preparing the catalyst of the present invention is to carry out a redox reaction between a trivalent Sb compound such as Sb ₂ O ₃ and a pentvalent V compound such as V ₂ O _5. After the reaction, at least a part of Sb is oxidized, at least Part of V is restored.

Convenient conditions for carrying out this redox reaction are heating to a minimum of 80°C _and not exceeding ₂₀₀ °C in an aqueous medium, for example, mixing a dispersion of a ^V15 compound such as _NH4VO3 or _V2O5 in water with a ^Sb3 The ⁺ compound is heated, usually mixed with an inorganic oxide support material, so that the average valence of V in it is lower than +5, and the average valence of the reacted Sb is higher than +3.

The obtained catalyst precursor slurry is dried and calcined in a gas containing molecular oxygen at a calcining temperature of 350-700° C., usually 400-650° C., to prepare a catalyst suitable for the ammoxidation of C ₃ -C ₄ alkane in the present invention. After the redox reaction, each of the additives A, H, C and/or T can be added to the slurry, or the solid particles containing V and Sb separated from the aqueous medium can be separated at any suitable stage before the final calcination of the catalyst These additional substances are coated or impregnated in a known manner.

If the V-Sb catalyst of the present invention is made by using 5-valent V and 5-valent Sb compounds, the redox reaction should be canceled, and both V and Sb remain in the highest oxidation state, regardless of adding or not adding substances , the resulting catalysts are all poor.

Therefore, according to the present invention, the excellent catalytic properties achieved by the ammoxidation of alkanes to produce corresponding unsaturated mononitriles and alkenes are obtained by using the catalyst of the present invention, which is a composite vanadium-antimony oxide containing Compositions of tungsten wherein V is in a lower oxidation state below +5 and Sb is in a higher oxidation state above +3 and also contains an inorganic oxide support.

Phosphorus and optional elements shown in formula (1) may be added to the basic vanadium/antimony/support precursor slurry, or to solids recovered from the slurry by general methods known in the art, Oxides, hydroxides, acids, salts (especially organic acid salts such as acetates) and other compounds of these elements are used for addition. Examples of adding these are given in the specific examples below.

Tungsten is advantageously added in the form of ammonium meta- or orthotungstate, tungstic acid and tungsten trioxide. P can be added in the form of ammonium phosphate or (NH ₄ ) ₂ HPO ₄ or phosphoric acid.

The catalyst support not only improves the mechanical stability of the catalyst, but also leads to a significant improvement in the catalyst activity.

Catalysts of formula (1) may, of course, contain other elements not mentioned in formula (1), but must have no substantial adverse effect on the catalyzed ammoxidation of alkanes to the desired nitriles. When bismuth in oxidized form is optionally used as a component of the catalyst of formula (1), it will generally be present in an amount such that V per atom does not exceed 0.2 atoms of Bi.

The weight ratio of catalyst to support/diluent material having components of experimental formula (1) can vary from 9:1 to 1:99.

In the method of the present invention, it is preferable to carry out the reaction in the gas phase, that is, the mixture of the alkane, ammonia and molecular oxygen-containing gas (such as air) is placed in a fixed bed, gravity fluidized bed, fluidized bed or fast transport reactor. The catalyst of the present invention in phase contact. It can also contain other diluents such as water vapor, nitrogen, _CO2 or He.

The molar ratio of alkane (such as propane) to molecular oxygen in the feed gas to the reaction zone can vary from 0.1:1 to 10:1, more usually from 0.2:1 to 8:1. The molar ratio of alkane (e.g. propane) to ammonia in the feed to the reaction zone can vary from 0.2:1 to 16:1, usually from 0.4:1 to 8:1. Particularly good results are obtained when the molar ratio of propane to _NH3 is in the range of 2-16 and the molar ratio of alkane to _O2 is in the range of 1-10, so the ratio of alkane to _O2 and _NH3 is related to the conversion of alkanes to nitriles The required stoichiometric amount is in large excess.

It should be noted that theoretically 100% conversion of alkanes cannot be achieved when the ratio of alkanes to oxygen and ammonia is in excess of the stoichiometric amount. However, when this is done, the advantage is that the selectivity of the alkanes to the corresponding nitriles and the corresponding alkenes is greatly increased, while the product alkenes can be further ammoxidized with _O2 and _NH3 to produce higher amounts of nitriles. Therefore, both nitriles and the corresponding alkenes are useful products in the present invention. Of course, unreacted alkenes and alkanes can be fed back to the ammoxidation process.

The reaction temperature ranges from 400-650°C, usually 460-520°C. The latter temperature range is especially suitable for the ammoxidation of propane to produce acrylonitrile.

The average contact time is usually 0.02-20 seconds, typically 0.2-8 seconds, although longer or shorter contact times can also be used.

Harris in U.S. Patent 3,860,534 discloses the ammoxidation of alkanes using a catalyst containing only V and Sb in oxide form and washed with water after calcination. The catalyst of the present invention is not washed with water and uses a combination of tungsten and an alumina-containing support which is the patentability of the invention.

British Patent 1,336,136 discloses the ammoxidation of alkanes using catalysts containing V and Sb in the form of oxides and optionally another metal oxide (only Sn is suggested). One carrier was said to be applicable, but the name of the carrier used was not indicated. British Patent 1,336,135 is a similar patent which discloses two or three component oxide catalysts, including certain catalysts containing both V and Sb. Neither tungsten nor alumina (support) is disclosed as useful for these catalysts.

None of the aforementioned patents disclose the presence of vanadium with an average valence lower than +5.

The ammoxidation of alkanes is also mentioned in Canadian Patent 901,006, and the disclosed catalyst contains oxide forms of any three metals selected from Sb, Sn, Ti, V and U, but does not include Sb-Sn-V combination. In addition, this patent does not disclose the V/Sb catalyst containing W, nor does it disclose the catalyst using an alumina carrier, nor does it disclose that the catalyst contains V whose average valence is lower than +5.

Shaw in U.S. Patent 4,138,366 discloses the conversion of unsaturated aldehydes to unsaturated acids using a catalyst containing Mo, Sb and V and containing a support material which may be alumina, but W is also not included in the list in optional elements.

Regarding the same reaction, U.S. Patent Nos. 3,773,692 and 3,867,345 disclose catalysts containing Mo, V, Sb, W.

Both of these patents state that alumina and silica are suitable supports. However, both patents prefer to use _SiO2 , diatomaceous earth and/or montmorillonite, and do not give examples of using supports with high alumina content. In all examples of both patents, the Mo:V ratios used are well outside the scope of the claimed invention. Furthermore, neither patent proposes a catalyst containing V with an average valence below +5 or Sb with an average valence above +3.

U.S. Patent 3,637,797 to Decker discloses the preparation of aromatic nitriles by alkyl-substituted aromatic hydrocarbons with ammonia and molecular oxygen in the presence of a catalyst containing V, Sb, alkali metals, Fe (optionally) and Oxides of W (optional) and alumina, where V is +5 and Sb is +3.

The following examples of the present invention are for demonstration purposes, but not to limit the present invention.

In these examples, conversion, yield and selectivity are defined as follows:

Conversion = (moles of alkanes reacted)/(moles of alkanes fed) × 100 (%)

Yield = (moles of product produced)/(moles of alkane fed) × 100 (%)

Selectivity = (moles of product produced)/(moles of alkane reacted) × 100 (%)

Example 1

A catalyst having the empirical formula composition _VSbPWOx (50% by weight) and _Al2O3 (50% by weight) was prepared as follows _:

Ammonium metavanadate (5.48 g) and ammonium metatungstate (12.64 g) were dissolved in about 100 ml of hot water. Then 85% phosphoric acid (5.34 grams) was added, and 20-30 milliliters of water was added at the same time, and the solution turned from yellow to red wine color at this time. Antimony trioxide (6.75 g) was added with vigorous stirring to give an initial red/orange slurry. The slurry was capped and allowed to "reflux" for 1 hour before turning dark blue/green in color.

In another beaker Catapal SB Al ₂ O ₃ (29.41 g, equivalent to 25.0 g Al ₂ O ₃ ) was slurried in 100 ml of water and peptized with glacial acetic acid (4.2 g) to form a sol-like Dispersed alumina. After aging for 1 hour, this dispersion was slowly added to the above blue/green slurry with enough water to prevent the slurry from gelling (about 100 ml). The resulting blue/green slurry was then evaporated on a hot plate until nearly completely dry, and the thick blue slurry was dried at 110° C. for about 16 hours. The dried catalyst precursor was heat-treated at 350°C for 5 hours, then ground and sieved to obtain 20-35 mesh particles. A portion of the sieved granules was then subjected to a final calcination at 610°C for 3 hours.

Example 2

A catalyst having the _same experimental formula composition VSb _0.5 PWO _x (50% by weight) _-Al2O3 (50% by weight) was prepared as in Example 1, but using the following quantities:

NH ₄ VO ₃ 7.16 g

Ammonium metatungstate 16.70g

85%H ₃ PO ₄ 7.06g

Sb ₂ O ₃ 0.89 g

Al ₂ O ₃ (Catapal SB alumina) 29.41 g

Example 3

A catalyst having the empirical formula composition VSb _0.5 P _1.5 WO _x (50% by weight)-Al ₂ O ₃ (50% by weight) was prepared as follows:

Dissolve ammonium metavanadate (5.82 g) and ammonium metatungstate (14, 62 g) in about 100 ml of hot water. Then add 85% phosphoric acid (6.18 g), and add 20-30 ml of water at the same time, the solution turns from yellow to red wine color. To this solution was added antimony trioxide (4.12 g) with vigorous stirring to give an initial red/orange slurry. The solution was capped and allowed to "reflux" for 1 hour, after which time the color changed to dark blue/green.

In another beaker, Catapal SB Al ₂ O ₃ (29.41 g, equivalent to 25.0 g Al ₂ O ₃ ) was slurried in 100 ml H ₂ O and peptized with glacial acetic acid (4.5 g) to form Sol-like alumina dispersion. After aging for 1 hour, the dispersion was slowly added to the blue/green slurry with sufficient water to prevent the slurry from gelling (approximately 100 ml added). The resulting blue/green slurry was evaporated to nearly dryness on a hot plate, and then the thick blue slurry was dried at 110° C. for about 16 hours. The dried catalyst precursor was heat treated at 350°C for 5 hours, then ground and sieved to obtain 20-35 mesh particles. A portion of the sieved particles was subjected to final calcination at 610°C for 3 hours.

Example 4

A catalyst having the _empirical formula composition VSb _0.1 PWO _x (50% by weight) _-Al2O3 (50% by weight) was prepared as follows:

Dissolve ammonium metavanadate (7.16) and ammonium metatungstate (16.70 g) in about 100 ml of hot water. Then add 85% phosphoric acid (7.06 grams), and add another 20-30 milliliters of water, the yellow color of the solution turns into red wine color. Antimony trioxide (0.89 g) was added with vigorous stirring to give an initial red/orange slurry. The slurry was capped and allowed to "reflux" for 1 hour before it changed color to dark blue/green.

In another _beaker , slurry Catapal SB _Al2O3 (29.41 _g , equivalent to 25.0 g _Al2O3 ) in 100 mL of water and peptize with glacial acetic acid (4.5 g) to form a quasi-sol alumina dispersion. After aging for 1 hour, the dispersion was added to the blue/green slurry along with sufficient water (about 100 ml) to prevent gelling. The resulting blue/green slurry was evaporated on a hot plate until nearly completely dry, and the resulting thick blue slurry was dried at 110° C. for about 16 hours. The dried catalyst precursor was heat treated at 350°C for 5 hours, then ground and sieved to obtain 20-35 mesh particles. A portion of the sieved particles was calcined at 610°C for 3 hours.

Example 5

A catalyst having the empirical formula composition VSb _0.1 P _1.5 WO _x (50% by weight)-Al ₂ O ₃ (50% by weight) was prepared as follows:

Ammonium metavanadate (6.59 g) and ammonium metatungstate (15.37 g) were dissolved in about 100 ml of hot water. Add 85% phosphoric acid (9.74 g), and add 20-30 ml of water at the same time, the solution turns from yellow to red wine color. Antimony trioxide (0.82 g) was added with vigorous stirring to give an initial red/orange slurry. The slurry was covered and allowed to "reflux" for 1 hour to change color to dark blue/green.

In another beaker, slurry Catapal SB Al ₂ O ₃ (29.41 g, equivalent to 25.0 g Al ₂ O ₃ ) in 100 ml of water and peptized with glacial acetic acid (4.5 g) to form a sol-like Aluminum oxide dispersion. After aging for 1 hour, the dispersion was slowly added to the blue/green slurry along with sufficient water (about 100 ml) to prevent gelling. The resulting blue/green slurry was evaporated on a hot plate until nearly completely dry, and the resulting thick blue slurry was dried at 110° C. for about 16 hours. The dried catalyst precursor was heat treated at 350°C for 5 hours, then ground and sieved to obtain 20-35 mesh particles. A part of the sieved material was roasted at 610° C. for 3 hours.

In the ammoxidation operation of the following examples, this catalyst is packed in a stainless steel tubular fixed-bed reactor with an internal diameter of 3/8 inches. The reactor is equipped with a preheating section immersed in a temperature-controlled molten salt bath. One hour after feeding the feedstock to the catalyst, the operation was officially started, and the product was collected and analyzed: for each example, the official operation time was 30-60 minutes.

Example 6

After each feed gas component is metered by the flow controller, it passes through the above-mentioned preheating section and enters the bottom of the reactor. The catalyst of Example 1 was used. Water is injected with a syringe through the diaphragm at the top of the preheating section. The reaction temperature is 470°C, and the feed molar ratio is propane:NH ₃ :O ₂ :H ₂ O=5:1:2:1. The contact time was 0.2 seconds. Analysis of the reactor effluent showed a 20.7% conversion of propane; a yield and selectivity to acrylonitrile of 4.0% and 19.5%, respectively; and a selectivity to propylene of 52.1%.

Example 7

After each feed gas component is metered by the flow controller, it enters the bottom of the reactor through the above-mentioned preheating section. The catalyst of Example 2 was used. Water is injected with a syringe through the septum located at the top of the preheating section. The reaction temperature is 470°C, and the feed molar ratio is propane:NH ₃ :O ₂ :H ₂ O=5:1:2:1. The contact time was 0.3 seconds. Analysis of the reactor effluent showed that the conversion of propane was 20.4%; the yield and selectivity to acrylonitrile were 4.1% and 20.1% respectively; the selectivity to propylene was 48.6%.

Example 8

After each feed component is metered by the flow controller, it enters the bottom of the reactor through the above-mentioned preheating section. The catalyst of Example 3 was used. Inject water with a syringe through the septum located on top of the preheating section. The reaction temperature is 470°C, and the feed molar ratio is propane:NH ₃ :O ₂ :H ₂ O=5:1:2:1. The contact time was 0.2 seconds. Analysis of the reactor effluent showed a propane conversion of 21.0%; a yield and selectivity to acrylonitrile of 4.3% and 20.6%, respectively; and a selectivity to propylene of 49.5%.

Example 9

After each feed component is metered by the flow controller, it passes through the above-mentioned preheating section and enters the bottom of the reactor. Using the catalyst of Example 5, water was injected with a syringe through the septum at the top of the preheating section. The reaction temperature is 470°C, and the feed molar ratio is propane:NH ₃ :O ₂ :H ₂ O=5:1:2:1. The contact time was 0.3 seconds. Analysis of the reactor effluent showed 21.0% conversion of propane; yield and selectivity to acrylonitrile were 3.7% and 17.8%, respectively; selectivity to propylene was 47.4%.

Example 10

After each feed component is metered by the flow controller, it enters the bottom of the reactor through the above-mentioned preheating section. The catalyst of Example 4 was used. Inject water with a syringe through the septum located on top of the preheating section. The reaction temperature is 470°C, and the feed molar ratio is propane:NH ₃ :O ₂ :H ₂ O=5:1:2:1. The contact time was 0.3 seconds. Analysis of the reactor effluent showed a conversion of propane of 20.5%; a yield and selectivity to acrylonitrile of 3.5% and 17.0%, respectively; and a selectivity to propylene of 48.6%.

The following are further catalyst compositions according to the invention in which there is a level of phosphorus acting as a promoter. When these catalysts were used for the ammoxidation of propane under the conditions of Example 7, the results obtained showed the same high percentage overall selectivity to acrylonitrile plus propylene.

50 wt% VSbSn _0.5 Te _0.5 Fe _0.5 P _0.5 WO _x +50 wt% Al ₂ O ₃

50 wt% VSb _0.8 P _0.5 W _0.5 Mo _0.5 O _x +50 wt% Al ₂ O ₃

50 wt% VSb _0.6 P _0.5 W ₃ O _x +25 wt% Al ₂ O ₃ +25 wt% SiO ₂

50 wt% VSbCoNiP _0.5 WO _x +50 wt% Al ₂ O ₃

50 wt% VSb _0.6 PWO _x +40 wt% Al ₂ O ₃ +10/wt% SiO ₂

50 wt% VSb _0.5 P _0.5 WCs _0.01 O _x +50 wt% Al ₂ O ₃

50 wt% VSbP ₃ CrWO _x +40 wt% Al ₂ O ₃ +10 wt% SiO ₂

50 wt% VSbP _0.5 W ₃ O _x +40 wt% Al ₂ O ₃ +10 wt% SiO ₂

(In the above data, "wt" means "weight")

It will be apparent to those skilled in the art that, based on the foregoing disclosure and discussion, and without departing from the spirit of the disclosure or beyond the scope of the claims of the present invention, various modifications can be made to the present invention. Revise.

Claims (18)

1, a kind of O composite metallic oxide catalyst, this catalyst have element and the ratio represented as following empirical formula:

V _RSb _mA _aH _bC _cT _tO _x

Wherein A is one or more among W, Sn, Mo, B, P and the Ge;

H is one or more among Fe, Co, Ni, Cr, Pb, Mn, Zn, Se, Te, Ga, Zr, In and the As;

C is that alkali metal is added one or more among the T1;

T is one or more among Ca, Sr, Mg, the Ba

Wherein m is 0.01-1; A is 0.2-10; B is 0-10; C is 0-1; T is 0-10; (a+b+c+t): ratio (l+m) is 0.1-6; For the V of each atom, the amount of Mo atom is no more than 2; Wherein X is the oxidation state that is decided by other elements; Also have wherein that the average valence mumber of Sb is higher than+3, the average valence mumber of V is lower than+and 5; Wherein A calculates the W that comprises at least 0.2 atom by the V of each atom; And contain a kind of carriers/diluents material in the above-mentioned catalyst, this material is to be selected from silica-alumina and aluminium oxide, and contains the aluminium oxide of 20-100% (weight).

2, the catalyst of claim 1, wherein the V of each atom contains the W of at least 0.4 atom.

3, the catalyst of claim 1, wherein the V of each atom contains the P of at least 0.5 atom.

4, the catalyst of claim 2, wherein the V of each atom contains the P of at least 0.5 atom.

5, the catalyst of claim 1 contains 50-100%(weight in the wherein said carriers/diluents) aluminium oxide.

6, the catalyst of claim 4 contains 50-100%(weight in the wherein said carriers/diluents) aluminium oxide.

7, the catalyst of claim 1 contains 60-100%(weight in the wherein said carriers/diluents) aluminium oxide.

8, the catalyst of claim 4 contains 60-100%(weight in the wherein said carriers/diluents) aluminium oxide.

9, use described catalyst, by C ₃-C ₄Alkane and oxygen and ammonia react, and produce C ₃-C ₄α, β-unsaturated mononitrile and C ₃-C ₄The method of monoene, this method are that aforementioned reactants is carried out catalytic reaction at a reaction zone by a kind of O composite metallic oxide catalyst, and described catalyst has element and the ratio represented as following empirical formula:

V _lSb _mA _aH _bC _cT _tO _x

Wherein A is one or more among W, Sn, Mo, B, P and the Ge;

H is one or more among Fe, Co, Ni, Cr, Pb, Mn, Zn, Se, Te, Ga, Zr, In and the As;

C is that alkali metal is added one or more among the Tl;

T is one or more among Ca, Sr, Mg and the Ba;

Wherein m is 0.01-1; A is 0.2-10; B is 0-10; C is 0-1; T is 0-10; (a+b+c+t): ratio (l+m) is 0.1-6; For the V of each atom, the amount of Mo atom is no more than 2; Wherein x is the oxidation state that is decided by other elements; Also have wherein that the average valence mumber of Sb is higher than+3, the average valence mumber of V is lower than+and 5; Wherein A calculates the W that comprises at least 0.2 atom by the V of each atom; And contain a kind of carriers/diluents material in the above-mentioned catalyst, this material is to be selected from silica-alumina and aluminium oxide, and contains 20-100%(weight) aluminium oxide.

10, the method for claim 9, the V of each atom contains the W of at least 0.4 atom in the wherein said catalyst.

11, the method for claim 9, the V of each atom contains the P of at least 0.5 atom in the wherein said catalyst.

12, the method for claim 10, the V of each atom contains the P of at least 0.5 atom in the wherein said catalyst.

13, the method for claim 9, in the charging of delivering to this reaction zone, described alkane is 1-10 to molecular oxygen molar ratio scope, described alkane is to NH ₃The molar ratio scope is 2-16.

14, the method for claim 9 contains 50-100%(weight in the wherein said carriers/diluents) aluminium oxide.

15, the method for claim 12 contains 50-100%(weight in the wherein said carriers/diluents) aluminium oxide.

16, the method for claim 9 contains 60-100%(weight in the wherein said carriers/diluents) aluminium oxide.

17, the method for claim 12 contains 60-100(weight in the wherein said carriers/diluents) aluminium oxide.

18, each method in the claim 9,10 and 12, wherein said alkane is to be selected from propane and iso-butane.