JP2000001464A - Production of nitrile from alkane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a nitrile in a high yield in high ammonia utilization efficiency under the reduced combustion of ammonia by subjecting an alkane to an ammoxydation reaction in the presence of a catalyst and a small amount of water in a gaseous phase. SOLUTION: This method for producing a nitrile comprises subjecting (A) an alkane (for example, propane) to an ammoxydation reaction in the presence of (B) a catalyst in a gaseous phase, while controlling the concentration of water in a gas charged in a gaseous phase reactor to 3-19 mol.%, preferably 4-18 mol.%. The component B preferably contains a compound oxide of the formula: MoVXZOn [X is tellurium or antimony; Z is niobium, tantalum, rare earth elements, alkaline earth metals or the like; the content ratios of the components excluding oxygen are expressed by the inequalities: 0.25<rMo<0. 98, 0.003<rV<0.5, 0.003<rX<0.5, 0<=rZ<0.5 (rMo, rV, rX and rZ are the mol fractions of Mo, V, X and Z on the basis of the total amount of the essential components excluding oxygen); (n) is determined by the oxidation states of the other elements].

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing nitriles from alkanes by ammoxidation and a method for simultaneously producing nitriles and carboxylic acids from alkanes. Nitriles such as acrylonitrile and methacrylonitrile are industrially important as important intermediates such as fibers, synthetic resins and synthetic rubbers.Carboxylic acids such as acrylic acid and methacrylic acid are used for various synthetic resins, paints and plasticizers. It is industrially important as a raw material.

[0002]

2. Description of the Related Art As a method for producing a nitrile, a so-called ammoxidation method in which an alkene is catalytically reacted with ammonia and oxygen in the gas phase at a high temperature in the presence of a catalyst,
As a method for producing a carboxylic acid, a production method in which an alkene is contact-reacted with oxygen in the gas phase at a high temperature in the presence of a catalyst is also known as a general method. On the other hand, methods for producing nitriles and carboxylic acids using less expensive alkanes as starting materials have been extensively studied, and various catalysts have been reported. As a catalyst containing molybdenum as an essential main element as a catalyst for nitrile production by gas phase catalytic oxidation reaction of alkane and ammonia,
Mo-Bi-P-based catalysts (JP-A-48-16887), catalysts obtained by mechanically mixing V-Sb-W-based oxides and Mo-Bi-Ce-W-based oxides (JP-A-48-16887) 1964-38
No. 051), a Mo-Ag-Bi-V catalyst (JP-A-3-58961), a Mo-V-Sn-Bi-P catalyst (JP-A-4-247060), a Mo-Cr-
Te-based catalysts (U.S. Pat. No. 5,171,876), composite metal oxide catalysts comprising Mo and elements such as Mn and Co (Japanese Patent Laid-Open No. 5-194347), Mo-V-Te-based catalysts (Japanese Patent Laid-Open No. 2-257) JP-A-5-148212, JP-A-5-208136, JP-A-6-27
9351, JP-A-6-287146 and JP-A-7-287146
-108101), a Mo-V-Sb-based catalyst (JP-A-9-157241), Mo-Cr-Bi
-Based catalyst (JP-A-7-215925), Mo-Te
A system catalyst (JP-A-7-215926) is exemplified.

[0003] Further, as a catalyst containing vanadium as an essential main element, a V-Sb-based catalyst (JP-A-47-337) has been proposed.
No. 83, Japanese Patent Publication No. 50-23016,
-268668, JP-A-2-180637), V-Sb-U-Ni-based catalyst (Japanese Patent Publication No. 47-143)
No. 71), a V-Sb-WP-based catalyst (Japanese Patent Laid-Open No. 2-9 / 1990).
No. 5439), VW-Te-based catalysts (JP-A-6-2)
28073) and the like.

[0004]

However, these methods for ammoxidizing alkanes are not satisfactory in yield when compared with the method for ammoxidizing alkenes. Further, when alkane is used as a raw material, the reactivity of alkane is low, so that it is necessary to use a catalyst having a strong oxidizing power or to perform a contact reaction at a high temperature, which causes a problem that combustion of ammonia increases. When the combustion of ammonia increases, the amount of ammonia used for nitrile production becomes insufficient, and more ammonia needs to be supplied, which is industrially disadvantageous. For these reasons, it has been desired that the loss due to the combustion of ammonia be reduced and that the ammonia be efficiently used in the ammoxidation reaction to produce nitriles. It is industrially advantageous if carboxylic acids, which are important as industrial raw materials, are simultaneously produced in the same reactor equipment as nitriles, and both can be obtained at a high yield simultaneously while controlling the ratio of nitriles and carboxylic acids.

[0005]

Means for Solving the Problems As a result of intensive studies in view of the above problems, the present inventors have found that when ammoxidation is carried out in the presence of a specific small amount of water, the combustion of ammonia is reduced and the use of ammonia is reduced. The present inventors have found that the efficiency can be improved, and as a result, the desired product can be obtained in a high yield, which has led to the present invention. That is, the gist of the present invention is to provide a method for producing a nitrile by ammoxidizing an alkane by a gas phase reaction in the presence of a catalyst, wherein the water concentration in the gas supplied to the gas phase reactor is 3 to 19
mol%, which is characterized in that it is adjusted to mol%.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The alkane used in the present invention includes, for example, alkanes such as methane, ethane, propane, n-butane, isobutane, pentane, hexane, heptane, and cyclohexane.When the industrial use of the obtained nitrile is considered, the number of carbon atoms is 1 to 1. It is preferable to use propane and / or isobutane from the viewpoint that acrylonitrile and methacrylonitrile can be obtained in a high yield as the lower alkane of No. 4, in particular, as the nitrile formed.

[0007] Ammoxidation is a method of performing an oxidation reaction in the presence of ammonia. The ammoxidation reaction is performed by supplying an oxygen-containing gas such as molecular oxygen together with ammonia into the reactor. Molecular oxygen is usually oxygen gas,
Although air is used, these may be diluted with nitrogen, helium, argon or the like which is inert to the reaction. The proportion of oxygen in the gas supplied to the reactor is not particularly limited, but is usually 0.1 to 10 times the molar amount of the alkane, preferably considering the yield and selectivity of acrylonitrile or acrylonitrile and acrylic acid to be generated, preferably The molar amount is 0.3 to 5 times, particularly preferably 0.5 to 4 times. Although the ratio of ammonia in the reaction gas supplied to the reactor is not particularly limited, it is usually 0.03 to 6 times the molar amount of the alkane,
The range is preferably 0.05 to 5 times by mole, and more preferably 0.1 to 4 times by mole.

A feature of the present invention is that water is supplied to a reactor when ammoxidation of an alkane is carried out in a gas phase reaction. As a result, the yield of the nitrile can be improved, and when the nitrile and the carboxylic acid are produced together, the yield of the total amount of the nitrile and the carboxylic acid can be improved. This is because water suppresses the combustion of ammonia, and ammonia is used more efficiently for ammoxidation. When a nitrile and a carboxylic acid are produced together, such an improvement in the utilization efficiency of ammonia improves the yield of the total amount, but may decrease the yield of the carboxylic acid alone. In such a case, by supplying water while controlling the amount of ammonia supplied to the reactor, the yields of nitrile and carboxylic acid can each be improved. Thus, by controlling the amount of water and the amount of ammonia supplied to the reactor, the ratio between the nitrile and the carboxylic acid to be produced can be arbitrarily controlled. However, considering the yield of the nitrile and the carboxylic acid content, the ratio of the carboxylic acid to the nitrile is usually 0.001-2 mol times, preferably 0.005-1.5 times times. It is preferable to carry out the reaction under the conditions. The method of supplying water is not particularly limited, but a method of supplying water to the reactor in a steam state together with the reaction gas is generally used. Specifically, production of acrylonitrile from propane, production of acrylonitrile and acrylic acid from propane,
It is effective for the production of methacrylonitrile from isobutane and the production of methacrylonitrile and methacrylic acid from isobutane. For example, in the reaction for producing acrylonitrile from propane and the reaction for producing acrylonitrile and acrylic acid from propane, when expressed as the concentration in the reaction gas supplied to the reactor, it is in the range of 3 to 19 mol%, preferably 4 to 18 mol%. %, More preferably 5 to 18 mol%. The amount of water supplied to the reactor is 19
If it is larger than mol%, the ammonia efficiency decreases, which is not preferable. The water concentration in the gas supplied to the reactor is 19
Under the reaction conditions of mol% or less, there is no particular limitation on the ratio of the amount of water supplied to the reactor to the amount of ammonia and the ratio of the amount of water supplied to the reactor to the amount of propane. However, considering the yield of acrylonitrile or acrylonitrile and acrylic acid formed,
The ratio of the amount of water supplied to the reactor to the amount of ammonia is usually 0.1 to 20 times, preferably 0.5 to 10 times, more preferably 0.7 to 7 times. The ratio of the amount of water supplied to the reactor to the amount of propane is usually 0.05 to 10 times, preferably 0.1 to 5 times, more preferably 0.2 to 4 times. Is preferred. In the present invention, the gas supplied to the reactor refers to all gases supplied to the reactor, such as alkane, ammonia, oxygen, water, and a gas inert to the reaction supplied to the reactor as a diluent. including.

Although there is no particular limitation on the catalyst used in the present invention, a catalyst represented by the following formula (I) is preferred as a catalyst that can more efficiently obtain nitriles from alkanes and nitriles and carboxylic acids from alkanes.

[0010]

Embedded image MoVXZO _n (I)

Wherein X is at least one element of tellurium and antimony, and Z is niobium, tantalum, tungsten, titanium, aluminum, zirconium, chromium, manganese, iron, ruthenium, cobalt, rhodium, nickel, palladium Represents one or more elements selected from the group consisting of platinum, bismuth, boron, indium, phosphorus, rare earth elements, and alkaline earth metals, and the proportion of each component excluding oxygen is represented by the following formula:

[0012]

Embedded image 0.25 <rMo <0.98 0.003 <rV <0.5 0.003 <rX <0.5 0 ≦ rZ <0.5

(Where rMo, rV, rX, and rZ represent the mole fractions of Mo, V, X, and Z with respect to the sum of the above essential components excluding oxygen), and n is determined by the oxidation state of other elements. Is done. As the Z component, niobium, tantalum, tungsten, and titanium are preferable, and niobium is particularly preferable. The proportions of Mo, V, X and Z are particularly preferably in the following ranges.

[0014]

Embedded image 0.4 <rMo <0.8 0.05 <rV <0.4 0.03 <rX <0.25 0.02 <rZ <0.25

The raw material of the composite metal oxide is not particularly limited as long as the molybdenum raw material is a raw material containing molybdenum, but is preferably ammonium paramolybdate, molybdenum trioxide, molybdic acid, molybdenum pentachloride, Molybdenyl acetylacetonate, molybdenum alkoxide, metal molybdenum solubilized with a suitable reagent, and the like are used, and ammonium paramolybdate is particularly preferably used. The vanadium raw material is not particularly limited as long as it is a raw material containing vanadium,
Preferably, ammonium metavanadate, vanadium pentoxide, vanadium oxychloride, metal vanadium solubilized with a suitable reagent, and the like are used, and particularly preferably, ammonium metavanadate is used. The tellurium raw material is not particularly limited as long as it is a raw material containing tellurium, but preferably, telluric acid, tellurium dioxide, tellurium trioxide, solubilized metallic tellurium with an appropriate reagent, and the like are used, and particularly preferably telluric acid. Is used. The antimony raw material is not particularly limited as long as it is a material containing antimony, but preferably, antimony trioxide, antimony chloride, a material obtained by solubilizing antimony metal with a suitable reagent or the like is used, and particularly preferably, antimony trioxide is used. Is done. Also, niobium, tantalum, tungsten, titanium,
Aluminum, zirconium, chromium, manganese, iron,
As a raw material of one or more elements selected from ruthenium, cobalt, rhodium, nickel, palladium, platinum, bismuth, boron and cerium, a compound containing each element or a metal of each element with an appropriate reagent Solubilized ones can be used. As the compound, carboxylate, ammonium carboxylate, ammonium oxyacid, ammonium halide, oxide, halide, hydrogen acid, acetylacetonate, alkoxide and the like can be used, but preferably carboxylate , Ammonium carboxylate and ammonium oxyacid are used. The method for preparing the composite metal oxide is not particularly limited, and a method in which each raw material of the composite metal oxide is mixed as a solution or slurry of water or an organic solvent and then prepared, and a method in which the raw materials of the composite metal oxide are mixed. And a method of preparing by a solid phase reaction by heating, and then a method of preparing a solution or a slurry-like aqueous liquid containing each component, followed by drying and baking is more preferable.

For example, as a method for producing a composite metal oxide containing molybdenum, vanadium, tellurium and niobium,
To an aqueous solution of ammonium metavanadate, an aqueous solution of telluric acid, an aqueous solution of niobium ammonium oxalate and an aqueous solution of ammonium paramolybdate are sequentially added in an amount ratio such that the atomic ratio of each metal element becomes a predetermined ratio. It can be obtained by drying by an evaporation to dryness method, a spray drying method, a freeze drying method, a vacuum drying method or the like to obtain a dried product, and then baking the obtained dried product. The firing method can be arbitrarily adopted depending on the properties and scale of the dried product, but heat treatment on an evaporating dish or heat treatment with a heating furnace such as a rotary furnace or a fluidized firing furnace is generally used. Further, a plurality of these processes may be combined. These firing conditions also vary depending on the method employed, but usually the temperature is 200-70.
0 ° C., preferably 250-650 ° C., usually for 0.5 hour
It is carried out for up to 30 hours, preferably 1 to 10 hours. Also,
The firing may be performed in the presence of oxygen, but is preferably performed in the absence of oxygen. Specifically, the firing is performed in an atmosphere of an inert gas such as nitrogen, argon, or helium or in a vacuum.

The catalyst obtained in this manner has a powder X-ray diffraction peak at the following diffraction angle when subjected to powder X-ray diffraction by a continuous method using Cu-Kα radiation. The intensity of the diffraction peak at 2θ = 22.1 ± 0.3 ° is 1
A catalyst having a specific structure in which the intensity of the diffraction peak at a diffraction angle 2θ = 27.3 ± 0.3 ° when set to 00 is 5 to 100 has a lower reaction temperature as compared with catalysts of other similar compositions. It is most preferable that the nitrile and carboxylic acid can be efficiently obtained from the alkane at 400 to 450 ° C.

[0018]

Table 2 Diffraction angle 2θ (°) ────────────6.7 ± 0.3 7.9 ± 0.3 9.0 ± 0.3 22.2 ± 0.3 27.3 ± 0.3 28.2 ± 0.3 35.4 ± 0.3 45.2 ± 0.3

The catalyst thus produced may be used alone, but may be any of well-known carrier components such as silica, alumina, titania, zirconia, aluminosilicate, and the like.
It may be used as a mixture containing about 1 to 90% by weight of diatomaceous earth and the like, and may also contain other metal oxides as a binder, metal oxides as a diluent, and the like. When using a carrier, a binder, a diluent, etc., the powder X-ray diffraction peak as a catalyst has a diffraction peak derived from a carrier, a binder, a diluent, etc., in addition to the diffraction peak derived from the composite oxide shown above. Is also good.

The reaction conditions for the ammoxidation vary depending on the composition of the reaction gas, the catalyst used, and the type of the nitrile or carboxylic acid to be produced, and are not determined uniquely. However, the reaction temperature is usually 350 to 600 ° C., preferably 380. ~ 500 ° C
And the gas hourly space velocity SV in the gas phase reaction is 50 to 10,000 h ^-1 , preferably 300 to 6000 h.
It is performed in the range of ^-1 . The reaction can usually be carried out under atmospheric pressure, but may be carried out under a slightly increased or reduced pressure. The reaction system may be a fixed bed, a fluidized bed, or the like. However, since the reaction is an exothermic reaction, the fluidized bed system is easier to control the reaction temperature. In addition, it can be carried out in a one-pass system in which the supplied alkane or ammonia is converted at a high rate, the conversion rate of the supplied alkane and the ammonia supply amount are kept low, the unreacted alkane is separated from the product, and again, It can also be carried out by a recycle method of supplying the reactor.

[0021]

EXAMPLES Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples unless it exceeds the gist. In the following Examples and Comparative Examples, the conversion (%) of propane (hereinafter, also referred to as “PPA”), the yield (%) of acrylonitrile (hereinafter, also referred to as “AN”), the total of acrylonitrile and acrylic acid, Amount (hereinafter also referred to as “AN + AA”) yield (%) and ammonia (NH ₃ ) utilization efficiency (%) are calculated by the following equations.

PPA conversion (%) = (moles of propane consumed / moles of propane fed) × 100 AN yield (%) = (moles of acrylonitrile formed /
(Moles of propane supplied) × 100 ・ (AN + AA) yield (%) = {(moles of acrylonitrile produced) + (moles of acrylic acid produced)} / moles of propane supplied × 100 ・ NH ₃ utilization efficiency ( %) = (Mol number of acrylonitrile formed / mol number of converted ammonia) × 100

Catalyst Production Example 1 A catalyst having the empirical formula Mo ₁ V _0.3 Nb _0.12 Te _0.23 O _x (90% by weight) / SiO ₂ (10% by weight) was prepared as follows. 789 g of ammonium paramolybdate tetrahydrate, 157 g of ammonium metavanadate and 236 g of telluric acid were dissolved in 3250 ml of warm water to obtain a uniform solution. Further, 565 g of a silica sol having a silica content of 20 wt% and a niobium concentration of 0.456 mol /
A slurry was prepared by mixing 1175 g of an aqueous niobium ammonium oxalate solution. The slurry was dried by removing water with a spray dryer having a center temperature of a dryer of 160 ° C. Next, the dried product was heated at 300 ° C. until the smell of ammonia disappeared, and then calcined at 600 ° C. for 2 hours in a nitrogen stream. Further, the catalyst thus obtained was subjected to X-ray diffraction measurement using Cu-Kα radiation as an X-ray source, and showed the following peaks and intensities.

[0024]

[Table 3] Diffraction angle 2θ (°) Relative intensity ──────────────────────6.7 ± 0.3 5.8 7.9 ± 0.3 14.6 9.0 ± 0.3 9.3 22.2 ± 0.3 100 27.3 ± 0.3 29.2 28.2 ± 0.3 58.0 35.4 ± 0.3 8.8 45.2 ± 0.3 11.5

Catalyst Preparation Example 2 A catalyst having the empirical formula Mo ₁ V _0.3 Nb _0.05 Sb _0.2 O _x (90% by weight) / SiO ₂ (10% by weight) was prepared as follows. 122 g of ammonium metavanadate and 102 g of antimony trioxide were added to 2100 ml of warm water, and the slurry was heated at 90 ° C. for 6 hours to remove water, and concentrated to about ／. This is called slurry A. Separately, 614 g of ammonium paramolybdate tetrahydrate salt was added to 1230 ml of warm water and dissolved,
To prepare an aqueous solution containing molybdenum. Further, 77 g of ammonium niobium oxalate was dissolved in 462 ml of warm water, and heated at 40 ° C. to prepare an aqueous solution containing niobium. The slurry and the aqueous solution were cooled to about 30 ° C., and the above-mentioned aqueous solution containing molybdenum, then 400 g of a silica sol having a silica content of 20 wt%, and the above-mentioned aqueous solution containing niobium were added to the slurry A, followed by stirring and mixing. Moisture was removed by a spray dryer having a center temperature of a dryer of 160 ° C., and drying was performed. Next, the dried product is heated at 300 ° C. until the smell of ammonia disappears, and then dried in a nitrogen stream.
It was baked at 0 ° C. for 2 hours. Further, the catalyst thus obtained was subjected to X-ray diffraction measurement using Cu-Kα radiation as an X-ray source, and showed the following peaks and intensities.

[0026]

[Table 4] Diffraction angle 2θ (°) Relative intensity ──────────────────────6.7 ± 0.3 6.9 7.9 ± 0.3 11.9 9.0 ± 0.3 9.9 22.2 ± 0.3 100 27.3 ± 0.3 20.8 28.2 ± 0.3 127.0 35.4 ± 0.3 5.5 45.2 ± 0.3 8.9

Example 1 A fixed bed flow reactor was charged with 0.55 g of the catalyst obtained in Catalyst Production Example 1, and the space velocity SV of the total gas was 680 hr.
⁻¹ , the reaction gas is PPA / NH ₃ / O ₂ / N ₂ / H
_It was supplied at a ratio of 2O = 1 / 1.2 / 3.3 / 10.7 / 1. In this reaction, the highest value of the acrylonitrile yield was obtained at 430 ° C., and the values of the acrylonitrile yield and the (acrylonitrile + acrylic acid) yield at 430 ° C. are shown in Table 1.

Example 2 The reaction gas was PPA / NH ₃ / O ₂ / N ₂ / H ₂ O = 1 /
The same reaction as in Example 1 was performed except that the mixture was supplied at a ratio of 1.2 / 3.3 / 9.7 / 2. In this reaction, 430 ° C
The highest acrylonitrile yield was obtained in
Table 1 shows the values of the acrylonitrile yield and the (acrylonitrile + acrylic acid) yield at 0 ° C.

Example 3 The reaction gas was PPA / NH ₃ / O ₂ / N ₂ / H ₂ O = 1 /
The same reaction as in Example 1 was performed except that the mixture was supplied at a ratio of 1.2 / 3.3 / 8.7 / 3. In this reaction, the highest value of acrylonitrile yield was obtained at 430 ° C.
Table 1 shows the values of acrylonitrile yield and (acrylonitrile + acrylic acid) yield at ° C.

Example 4 0.55 g of the catalyst obtained in Catalyst Production Example 1 was charged into a fixed-bed flow reactor, and the space velocity SV of the total gas was 680 hr.
⁻¹ , the reaction gas is PPA / NH ₃ / O ₂ / N ₂ / H
₂ O = 1 / 1.0 / 3.3 / 10.7 / 1. In this reaction, the highest value of the acrylonitrile yield was obtained at 420 ° C., and the values of the acrylonitrile yield and the (acrylonitrile + acrylic acid) yield at 420 ° C. are shown in Table 1.

Example 5 The reaction gas was PPA / NH ₃ / O ₂ / N ₂ / H ₂ O = 1 /
The same reaction as in Example 4 was performed except that the mixture was supplied at a ratio of 1.0 / 3.3 / 9.7 / 2. In this reaction, 420 ° C
The highest acrylonitrile yield was obtained in
Table 1 shows the values of the acrylonitrile yield and the (acrylonitrile + acrylic acid) yield at 0 ° C.

Example 6 The reaction gas was PPA / NH ₃ / O ₂ / N ₂ / H ₂ O = 1 /
The same reaction as in Example 4 was performed except that the mixture was supplied at a ratio of 1.0 / 3.3 / 8.7 / 3. In this reaction, 430 ° C
The highest acrylonitrile yield was obtained in
Table 1 shows the values of the acrylonitrile yield and the (acrylonitrile + acrylic acid) yield at 0 ° C.

Example 7 0.55 g of the catalyst shown in Catalyst Production Example 1 was applied to a fixed bed flow type
And the space velocity SV of the total gas is 680 hr^-1
The reaction gas is PPA / NH_Three/ O_Two/ N _Two/ H_Two
O = 1 / 0.8 / 3.3 / 10.7 / 1
Was. In this reaction, the acrylonitrile yield was
Acrylonit at 410 ° C
Ryl yield and (acrylonitrile + acrylic acid) yield
Are shown in Table 1.

Example 8 The reaction gas was PPA / NH ₃ / O ₂ / N ₂ / H ₂ O = 1 /
The same reaction as in Example 7 was performed except that the mixture was supplied at a ratio of 0.8 / 3.3 / 9.7 / 2. In this reaction, 410 ° C
The highest value of acrylonitrile yield was obtained in
Table 1 shows the values of the acrylonitrile yield and the (acrylonitrile + acrylic acid) yield at 0 ° C.

Example 9 The reaction gas was PPA / NH ₃ / O ₂ / N ₂ / H ₂ O = 1 /
The same reaction as in Example 7 was performed, except that the mixture was supplied at a ratio of 0.8 / 3.3 / 8.7 / 3. In this reaction, 420 ° C
The highest acrylonitrile yield was obtained in
Table 1 shows the values of the acrylonitrile yield and the (acrylonitrile + acrylic acid) yield at 0 ° C.

Example 10 0.1 g of the catalyst obtained in Catalyst Production Example 1 was charged into a fixed-bed flow reactor, and the space velocity SV of the entire gas was set to 5000 hr.
^-1 and the reaction gas is PPA / NH ₃ / O ₂ / N ₂ /
H ₂ O was supplied at a ratio of 1 / 0.3 / 0.88 / 2.82 / 0.3. The propane conversion obtained in this reaction is 2
Table 1 shows the yield of acrylonitrile and the yield of (acrylonitrile + acrylic acid) at 5%.

Example 11 The reaction gas was changed to PPA / NH ₃ / O ₂ / N ₂ / H ₂ O = 1 /
The same reaction as in Example 10 was performed, except that the mixture was supplied at a ratio of 0.3 / 0.88 / 2.52 / 0.6. Table 1 shows the yields of acrylonitrile and (acrylonitrile + acrylic acid) when the conversion of propane obtained by this reaction is 25%.

Example 12 0.1 g of the catalyst obtained in Catalyst Production Example 1 was charged into a fixed-bed flow reactor, and the space velocity SV of the entire gas was set to 5000 hr.
^-1 and the reaction gas is PPA / NH ₃ / O ₂ / N ₂ /
H ₂ O was supplied at a ratio of 1 / 0.1 / 0.88 / 2.52 / 0.6. The propane conversion obtained in this reaction is 2
Table 1 shows the yield of acrylonitrile and the yield of (acrylonitrile + acrylic acid) at 5%.

Example 13 A fixed bed flow reactor was charged with 0.15 g of the catalyst obtained in Catalyst Production Example 2, and the space velocity SV of the total gas was 680 hr.
^-1 and the reaction gas is PPA / NH ₃ / O ₂ / N ₂ /
H ₂ O was supplied at a ratio of 1 / 0.3 / 0.88 / 2.82 / 0.3. The propane conversion obtained in this reaction is 2
Table 1 shows the yield of acrylonitrile and the yield of (acrylonitrile + acrylic acid) at 5%.

Comparative Example 1 The reaction gas was PPA / NH ₃ / O ₂ / N ₂ = 1 / 1.2 /
The same reaction as in Example 1 was carried out except that the mixture was supplied at a ratio of 3.3 / 11.7. In this reaction, the highest value of the acrylonitrile yield was obtained at 410 ° C., and thus the values of the acrylonitrile yield and (acrylonitrile + acrylic acid) yield at 410 ° C. are shown in Table 1.

Comparative Example 2 The reaction gas was PPA / NH ₃ / O ₂ / N ₂ / H ₂ O = 1 /
The same reaction as in Example 1 was performed except that the mixture was supplied at a ratio of 1.2 / 3.3 / 7.7 / 4. In this reaction, 430 ° C
The highest acrylonitrile yield was obtained in
Table 1 shows the values of the acrylonitrile yield and the (acrylonitrile + acrylic acid) yield at 0 ° C.

Comparative Example 3 The reaction gas was PPA / NH ₃ / O ₂ / N ₂ / H ₂ O = 1 /
The same reaction as in Example 1 was performed except that the mixture was supplied at a ratio of 1.2 / 3.3 / 6.7 / 5. In this reaction, 430 ° C
The highest acrylonitrile yield was obtained in
Table 1 shows the values of the acrylonitrile yield and the (acrylonitrile + acrylic acid) yield at 0 ° C.

Comparative Example 4 The reaction gas was PPA / NH ₃ / O ₂ / N ₂ = 1 / 1.0 /
The same reaction as in Example 4 was performed except that the mixture was supplied at a ratio of 3.3 / 11.7. In this reaction, the highest value of the acrylonitrile yield was obtained at 410 ° C., and thus the values of the acrylonitrile yield and (acrylonitrile + acrylic acid) yield at 410 ° C. are shown in Table 1.

Comparative Example 5 The reaction gas was PPA / NH ₃ / O ₂ / N ₂ = 1 / 0.8 /
The same reaction as in Example 7 was performed, except that the mixture was supplied at a ratio of 3.3 / 11.7. In this reaction, the highest value of the acrylonitrile yield was obtained at 410 ° C., and thus the values of the acrylonitrile yield and (acrylonitrile + acrylic acid) yield at 410 ° C. are shown in Table 1.

Comparative Example 6 The reaction gas was PPA / NH ₃ / O ₂ / N ₂ = 1 / 0.3 /
Example 10 except that it was supplied at a ratio of 0.88 / 3.12.
The same reaction as described above was performed. Table 1 shows the yields of acrylonitrile and (acrylonitrile + acrylic acid) when the conversion of propane obtained by this reaction is 25%.

Comparative Example 7 The reaction gas was PPA / NH ₃ / O ₂ / N ₂ = 1 / 0.1 /
Example 12 except that it was supplied at a ratio of 0.88 / 3.12.
The same reaction as described above was performed. Table 1 shows the yields of acrylonitrile and (acrylonitrile + acrylic acid) when the conversion of propane obtained by this reaction is 25%.

Comparative Example 8 The reaction gas was PPA / NH ₃ / O ₂ / N ₂ = 1 / 0.3 /
Example 13 except that it was supplied at a ratio of 0.88 / 3.12.
The same reaction as described above was performed. Table 1 shows the yields of acrylonitrile and (acrylonitrile + acrylic acid) when the conversion of propane obtained by this reaction is 25%.

[0048]

[Table 5]

[0049]

According to the method of the present invention, in producing a nitrile or a nitrile and a carboxylic acid by ammoxidation of an alkane, water is supplied to a reactor to improve the efficiency of ammonia utilization, thereby improving the efficiency. Nitriles or nitriles and carboxylic acids can be produced from alkanes.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takashi Ushikubo 1st Toho-cho, Yokkaichi-shi, Mie F-term in Yokkaichi Office of Mitsubishi Chemical Corporation (reference) 4G069 AA03 AA08 BA02C BA21C BA37 BB01A BB01B BB01C BB04A BB04B BB04C BB06A BB06 BC16A BC25A BC26A BC26B BC26C BC38A BC50A BC51A BC54A BC54B BC55A BC55B BC55C BC56A BC58A BC59A BC59B BC59C BC60A BC62A BC66A BC67A BC68A BC70A BC71A BC72A BC74A BC75A BD01C BD03A BD06C BD07B10 CB10A BD06C BD07A BA10 BA12 BA13 BA14 BA16 BA19 BA20 BA21 BA25 BA26 BA30 BE14 BE30 QN24 4H039 CA70 CL50

Claims (5)

[Claims] 1. A method for producing nitrile by ammoxidizing alkanes by a gas phase reaction in the presence of a catalyst, wherein the concentration of water in a gas supplied to a gas phase reactor is adjusted to 3 to 19 mol%. A method for producing a nitrile. 2. The method for producing a nitrile according to claim 1, wherein the nitrile and the carboxylic acid are produced simultaneously. 3. The method for producing a nitrile according to claim 1, wherein the catalyst contains a composite oxide represented by the formula (I). ## STR1 ## MoVXZO _n ···· (I) (wherein, X is tellurium, one element among antimony, Z is niobium, tantalum, tungsten, titanium, aluminum, zirconium, chromium, manganese, iron One or more elements selected from the group consisting of, ruthenium, cobalt, rhodium, nickel, palladium, platinum, bismuth, boron, indium, phosphorus, rare earth elements, alkaline earth metals, and the presence of each component except oxygen The ratio is represented by the following formula: 0.25 <rMo <0.98 0.003 <rV <0.5 0.003 <rX <0.50 ≦ rZ <0.5 (provided that rMo, rV, rX and rZ satisfy the molar fraction of Mo, V, X and Z with respect to the sum of the above essential components excluding oxygen), and n is determined by the oxidation state of other elements.) 4. The composite oxide represented by the formula (I) is as shown in Table 1.
Shows the powder X-ray diffraction peak at the diffraction angle shown in FIG.
2. The diffraction peak intensity at a diffraction angle 2θ = 27.3 ± 0.3 °, where the intensity of a diffraction peak at 22.2 ± 0.3 ° is 100, is 5 to 100. 4. The method for producing a nitrile according to any one of claims 3 to 3. Table 1 Diffraction angle 2θ (°) ──────────── 6.7 ± 0.3 7.9 ± 0.3 9.0 ± 0.3 22.2 ± 0.3 27.3 ± 0.3 28.2 ± 0.3 35.4 ± 0.3 45.2 ± 0.3 5. The method for producing a nitrile according to claim 1, wherein the concentration of water in the gas supplied to the gas-phase reactor is adjusted to 5 to 18 mol%.