JPH06228074A - Production of nitrile - Google Patents

Abstract

PURPOSE:To produce a nitrile from an alkane under relatively low-temperature conditions in high yield. CONSTITUTION:An alkane is subjected to vapor phase catalytic oxidation reaction with ammonia in the presence of a solid catalyst obtained by adding either one or more oxides of manganese, chromium, gallium, germanium, yttrium and lead to the complex oxide of the following formula: MoaVbTecXxOn [X are one or more elements selected from Tb, Ta, W, Ti, Al, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ni, Pd, Pt, Sb, Bi, B, In and Ce and when a is 1, b is 0.01-1.0, c is 0.01-1.0 and x is 0.01-1.0; and n is determined by oxidation state of other elements].

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing nitrile. More particularly, it relates to an improved nitrile production method using alkane as a raw material.

[0002]

2. Description of the Related Art Nitriles such as acrylonitrile and methacrylonitrile are industrially produced as important intermediates for fibers, synthetic resins, synthetic rubbers and the like. The most general method is to react an olefin such as the above with an ammonia and oxygen in the presence of a catalyst in a gas phase at a high temperature.

On the other hand, due to the price difference between propane and propylene or the price difference between isobutane and isobutene, lower alkanes such as propane and isobutane are used as starting materials, and ammonia and oxygen are used in the presence of a catalyst. There is an increasing interest in the development of a method for producing acrylonitrile and methacrylonitrile by a so-called ammoxidation reaction method in which they are catalytically reacted with each other in a gas phase.

As an example of these reports, Mo-Bi-P
-O catalyst (Japanese Patent Laid-Open No. 48-16887), V-Sb-
O-based catalyst (JP-A-47-33783, JP-B-50-2)
No. 3016, JP-A-1-268668), Sb-U-
V-Ni-O catalyst (Japanese Patent Publication No. 47-14371), S
b-Sn-O type catalyst (Japanese Patent Publication No. 50-28940), V
-Sb-W-P-O catalyst (Japanese Patent Laid-Open No. 95439/1990)
No.), V-Sb-W-O-based oxide and Bi-Ce-Mo-
A catalyst obtained by mechanically mixing W—O type oxides (Japanese Patent Application Laid-Open No. Sho 6-96).
4-38051) and the present inventors
o-V-Te-Nb-O based catalyst (JP-A-2-257)
Is reported.

[0005]

However, none of these methods can sufficiently satisfy the target yield of nitriles. In addition, in order to improve the yield of nitriles, a method of adding a small amount of an organic halide, an inorganic halide, a sulfur compound, or water to the reaction system has been attempted, but the former three are not There is a problem of corrosion, and water has a problem of generation of a by-product due to a side reaction and its treatment, which are both difficult in industrial implementation.

Further, the conventional method using a catalyst system generally requires an extremely high reaction temperature of about 500 ° C. or higher except for the Mo-V-Te-Nb-O catalyst reported by the present inventors. Therefore, it is not advantageous in terms of reactor material, manufacturing cost, and the like.

[0007]

Means for Solving the Problems The present inventors
As a result of further studying a method for producing a nitrile using an alkane as a raw material, focusing on improvement of an o-V-Te-Nb-O-based catalyst, a Mo-V-Te-X-O-based catalyst (X is one kind or It represents a plurality of kinds of specific elements) (Japanese Patent Application No. 3-104382). Furthermore, the same Mo-V-Te-
It has been found that when an X-O type catalyst having a specific crystal structure is used, the yield of nitrile is significantly improved (Japanese Patent Application No. 3-199573).

The inventors of the present invention have been focusing on further study based on the recent research results, and found that Mo-V-Te-X
After preparing a —O-based composite oxide, the composite oxide is further
In the presence of a solid catalyst obtained by adding a specific substance such as manganese oxide, by reacting an alkane with ammonia in a gas-phase contact reaction, halides, water, etc. do not exist in the reaction system, The inventors have found that the target nitrile can be produced with a higher yield than the conventional method at a relatively low temperature of about 450 ° C. and have reached the present invention.

[0009] That is, the gist of the present invention has the following formula _{(1) Mo a V b Te} c X x O n (1) in (Equation (1), X is Nb, Ta, W, Ti, A
1, Zr, Cr, Mn, Fe, Ru, Co, Rh, N
represents one or more elements selected from i, Pd, Pt, Sb, Bi, B, In and Ce, and a = 1
Where, b = 0.01 to 1.0 c = 0.01 to 1.0 x = 0.01 to 1.0, and n is determined by the oxidation states of other elements. In the presence of a solid catalyst composed of one or more oxides of manganese, chromium, gallium, germanium, yttrium, and lead antimony, added to the complex oxide represented by), the alkane is reacted with ammonia in the gas phase catalytic oxidation reaction It exists in the manufacturing method of the nitrile characterized by making it do.

The present invention will be described in detail below. In the complex oxide of the above formula (1) prepared first in the present invention, the above element is used as X, but preferably Nb, Ta,
W and Ti. Further, as the coefficient of the equation (1), a = 1
, B = 0.1-0.6, c = 0.05-0.
4, x = 0.01 to 0.6 is particularly preferable.

Further, the complex oxide preferably has a specific crystal structure. Specifically, as the pattern of the X-ray diffraction peak (using Cu-Kα ray as the X-ray source) of the composite oxide, the following five main diffraction peaks are observed at a specific diffraction angle 2θ. .

[0012]

[Table 1] X-ray grating plane diffraction angle 2θ (°) Interval median value (Å) Relative intensity 22.1 ± 0.3 4.02 100 28.2 ± 0.3 3.16 20 to 150 36.2 ± 0.3 2.48 5-60 45.2 ± 0.3 2.00 2-40 50.0 ± 0.3 1.82 2-40

The X-ray diffraction peak intensity may deviate depending on the measurement conditions of each crystal, but the relative intensity is usually in the above range when the peak intensity at 2θ = 22.1 ° is 100. Also, in general, 2θ = 22.1 ° and 28.2.
The peak intensity at ° appears significantly. Even if a small amount of a specific oxide to be described later is added to the composite oxide having such a crystal structure and a treatment such as mixing and firing is performed, the X-ray diffraction pattern of the obtained substance is almost the same, and particularly No change in crystal structure is observed.

The method for preparing the composite oxide is as follows.
For example, Mo_aV_bTe_cNb_xO _nIn case of
Tellurium was added to an aqueous solution containing ammonium metavanadate.
Aqueous acid solution, niobium oxalate ammonium salt solution
And an aqueous solution of ammonium paramolybdate
Sequentially in a quantitative ratio such that the atomic ratio of metal elements is a predetermined ratio
Add and dry by evaporation drying method, spray drying method, vacuum drying method, etc.
Finally, the remaining dried product is usually heated to 350 to 700.
℃, preferably at a temperature of 400 ~ 650 ℃, usually 0.5
For 30 to 30 hours, preferably 1 to 10 hours
It is a composite oxide.

Regarding the above-mentioned calcination method, the most general method is to carry out in an oxygen atmosphere, but in order to obtain a complex oxide having the above-mentioned specific structure, the calcination atmosphere is rather absent of oxygen. It is preferable to set it below. Specifically, it is carried out in an atmosphere of an inert gas such as nitrogen, argon or helium, or in vacuum.

The raw materials for the above-mentioned composite oxide are as described above.
Not limited to one, Nb ₂O_Five, V₂O_Five，
V₂O₃, TeO₂, MoO₃Oxides such as NbCl_Five，
VCl_Four, VOCl₃, MoCl_FiveSuch as halide or
Is oxyhalide, Mo (OC₂H_Five)_Five, Nb (O
C₂H_Five)_Five, VO (OC₂H_Five)₃Alkoxide, etc.
Other various molybdenum acetylacetonates and other organic metals
It is possible to select raw material compounds from a wide range such as compounds.
Wear

The complex oxide of the formula (1) prepared as described above has activity as a solid catalyst as it is, but in the present invention, in order to further improve the selectivity and yield of nitrile. In addition, it is characterized in that a substance obtained by adding a specific oxide to the composite oxide is used as a solid catalyst. As the specific oxide, one or more kinds of oxides of manganese, chromium, gallium, germanium, yttrium and lead are used, and oxides of manganese and germanium are particularly preferable.

As the manganese oxide to be added, MnO
, Mn ₃ O ₄ , Mn ₂ O ₃ , MnO ₂ , Mn ₂ O, Mn ₈ O
₇ etc. are illustrated. These oxides may be used alone or as a mixture of two or more kinds, and may be used in the form of hydrate.
In some cases, MnCl ₂ , MnCO ₃ , MnC
It is also possible to add a compound containing manganese such as ₂ O _{4 to} the composite oxide of the formula (1) and calcined to use as a solid catalyst. In this case, the manganese-containing compound is converted into manganese oxide by firing.

The chromium oxide added is C
Examples thereof include rO, Cr ₂ O and CrO ₃ . These oxides may be used alone or as a mixture of two or more kinds, and may be used in the form of hydrate. In some cases, CrC
Compounds containing chromium such as l ₂ , CrCl ₃ and Cr (NO) ₃ may be added to the composite oxide of the formula (1) and the calcined material may be used as a solid catalyst. In these cases,
It is converted to chromium oxide by firing the chromium-containing compound.

As the gallium oxide, Ga ₂ O is used.
, Ga ₂ O _{3 and the} like are exemplified. These oxides may be used alone or as a mixture of two or more kinds, and may be used in the form of hydrate. In addition, depending on the case, GaCl ₂ , GaCl ₃
It is also possible to add a compound containing gallium such as the above to the composite oxide of the formula (1) and calcined to use as a solid catalyst. In these cases, the gallium-containing compound is converted into gallium oxide by firing.

As the germanium oxide, Ge is used.
₂ O , Ge ₂ O _{3 and the} like. These oxides are 1
It may be a kind or a mixture of plural kinds, and may be used in the form of a hydrate. In some cases, GeCl ₂ , Ge
It is also possible to add a compound containing germanium such as Cl _{4 to} the complex oxide of the formula (1) and calcined to use as a solid catalyst. In these cases, the germanium-containing compound is converted into germanium oxide by firing.

Further, as yttrium oxide to be added
Is Y₂O₃Is generally used, but it may be used in the form of hydrate.
Yes. In some cases, YCl₃, Y (NO)₃, Y₂
(C ₂O_Four)₃Compounds containing yttrium such as
A solid catalyst obtained by adding a substance to the composite oxide of (1) and firing
Can also be used as In these cases, it Liu
Yttrium oxide
Is converted to.

As lead oxide to be added, Pb ₂ O, P
bO , Pb ₃ O ₄ , Pb ₂ O ₃ , PbO _{2 and the} like. These oxides may be used alone or as a mixture of two or more kinds, and may be used in the form of hydrate. In some cases, Pb (NO) ₃ , PbOH, PbCO ₃ , Pb
It is also possible to add a compound containing lead such as C ₂ O _{4 to} the composite oxide of the formula (1) and calcined to use as a solid catalyst. In this case, the lead compound is converted into lead oxide by firing.

The above-mentioned method of adding the specific oxide to the composite oxide is carried out while crushing and mixing both of them so that the contact of the specific oxide with the composite oxide is effectively performed.
The amount of the specific oxide added to the composite oxide is usually 0.0001 to 0.2, preferably 0.001 to 0.05, by weight ratio with respect to the composite oxide. After the addition, it may be used as it is in the reaction for producing nitriles from alkane, but it is preferably usually 300 to 650 ° C, particularly 35
Bake at 0-600 ° C. The firing is preferably carried out in an atmosphere of an inert gas such as nitrogen, argon or helium, and the gas may contain a reducing gas such as hydrogen, ammonia or hydrocarbon, or steam, or is carried out in vacuum.

The substance composed of the complex oxide of the formula (1) thus obtained and the oxide of manganese or the like can be used as a solid catalyst by itself, but it is a well-known carrier such as silica, alumina or titania. It can also be used with aluminosilicate, diatomaceous earth, etc. In this case, the carrier as described above may be used when preparing the complex oxide of the formula (1) or may be used when adding antimony oxide. Further, it is molded into an appropriate shape and particle size depending on the scale of reaction, method, and the like.

The method of the present invention is to produce a nitrile by subjecting an alkane to a gas phase catalytic oxidation reaction with ammonia in the presence of the above-mentioned oxide. In the present invention, the alkane as a raw material is not particularly limited, and examples thereof include methane, ethane, propane, n-butane,
Examples include isobutane, pentane, hexane, heptane, etc., but considering the industrial use of the resulting nitrile,
It is preferable to use a lower alkane having 1 to 4 carbon atoms, particularly propane or isobutane.

Although the details of the mechanism of the oxidation reaction in the present invention are not clear, it is carried out by oxygen atoms present in the above oxide or molecular oxygen present in the feed gas. When molecular oxygen is present in the feed gas, the molecular oxygen may be pure oxygen gas, but it is economical to use an oxygen-containing gas such as air since purity is not particularly required. Alkane, a mixed gas of ammonia and an oxygen-containing gas is usually used as the supply gas, but a mixed gas of an alkane and ammonia and an oxygen-containing gas may be alternately supplied.

It is also possible to carry out a gas phase catalytic reaction using only alkane and ammonia, which are substantially free of molecular oxygen, as feed gases. In such a case, it is preferable to appropriately withdraw a part of the catalyst from the reaction zone, feed the catalyst to an oxidation regenerator, and regenerate the catalyst to re-feed it to the reaction zone. As a method of regenerating the catalyst, the catalyst is oxygen, air,
Oxidizing gas such as nitric oxide to the catalyst in the regenerator,
A typical method is to circulate at 300 to 600 ° C.

In the case of using propane as the alkane and air as the oxygen source, the present invention will be described in more detail. The reactor system may be either a fixed bed or a fluidized bed, but since it is an exothermic reaction, It is easier to control the reaction temperature in the fluidized bed method. The ratio of air supplied to the reaction is important with respect to the selectivity of acrylonitrile to be produced, and the air usually shows a high acrylonitrile selectivity in a range of 25 mol times or less, particularly 1 to 15 mol times with respect to propane. . The proportion of ammonia supplied to the reaction is 0.2 to 5 times the molar amount of propane, particularly 0.1.
A range of 5 to 3 molar times is suitable. The reaction is usually carried out under atmospheric pressure, but it can also be carried out under slightly elevated pressure or reduced pressure. For other alkanes, the composition of the feed gas is selected according to the conditions for propane.

In the method of the present invention, the temperature is lower than that in the conventional ammoxidation reaction of alkane, for example, 34
It can be carried out at 0 to 480 ° C, particularly preferably at about 380 to 440 ° C. Even at such a low temperature, nitriles can be produced in a high yield as compared with conventional techniques. The gas space velocity SV in the gas phase reaction is usually 100 to 10000 h ^-1 , preferably 30.
It is in the range of ⁰ to 2000 h ⁻¹ . An inert gas such as nitrogen, argon, or helium can be used as a diluent gas for adjusting the space velocity and the oxygen partial pressure. When the ammoxidation reaction of propane is carried out by the method of the present invention, carbon monoxide, carbon dioxide, acetonitrile, hydrocyanic acid, and the like are by-produced in addition to acrylonitrile, but the amount produced is extremely small.

[0031]

The present invention will be described in more detail below with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples unless it exceeds the gist. The conversion rate (%) in the following examples and comparative examples,
The selectivity (%) and the yield (%) are respectively shown by the following equations.

[0032]

[Formula 1] Alkane conversion rate (%) = (mol number of consumed alkane / mol number of supplied alkane) × 100 Selectivity of target nitrile (%) = (mol number of target nitrile to be produced / mol number of consumed alkane) × 100 Yield (%) of target nitrile = (mol number of nitrile for production / mol number of alkane supplied) × 100

Example 1 A composite oxide having the empirical formula Mo ₁ V _0.3 Te _0.23 Nb _0.12 O _n was prepared as follows. 15.7 g of ammonium metavanadate was dissolved in 325 ml of warm water, and 23.6 g of telluric acid and 78.9 g of ammonium paramolybdate were sequentially added thereto to prepare a uniform aqueous solution. Furthermore, 117.5 g of a niobium ammonium oxalate aqueous solution having a niobium concentration of 0.456 mol / kg was mixed to prepare a slurry. The slurry was evaporated to dryness to give a solid. 5 mm of this solid using a tablet press
After being molded into Φ × 3 mmL, it was pulverized, sieved to 16 to 28 mesh, and fired at 600 ° C. for 2 hours in a nitrogen stream.

Powder X-ray diffraction measurement of the thus obtained composite oxide (using Cu-Kα ray) revealed that the diffraction angles 2θ (°) were 22.1 (100), 28.2.
(90.0), 36.2 (25.7), 45.1 (1
The major diffraction peaks were observed at 5.2) and 50.0 (16.3) (the number in parentheses indicates the peak at 22.1 ° is 1).
The relative peak intensity when 00 is shown. ).

Next, 30 g of the composite oxide was ground in a mortar, and 0.3 g of manganese oxide (MnO ₂ ) was further added and mixed. 5 mmΦ x 3 of this mixture using a tablet press
After molding into mmL, it was pulverized, sieved to 16 to 28 mesh, and fired at 550 ° C for 2 hours in a nitrogen stream. 0.5 ml of the solid catalyst thus obtained was charged into a reactor, the reaction temperature was 410 ° C., the space velocity SV was fixed at 1300 h ^−1, and the molar ratio of propane: ammonia: air = 1: 1.2: 15. Table 1 shows the results of the gas-phase catalytic reaction performed by supplying the gas at a ratio.

Example 2 Using the solid catalyst prepared in Example 1, the space velocity SV was 1
Table 1 shows the results of the gas phase catalytic oxidation reaction of propane under the same reaction conditions as in Example 1 except that the reaction time was set to 9000 h ^-1 .

Example 3 Complex oxide 30 prepared as described in Example 1
g was crushed, 0.3 g of chromium oxide (Cr ₂ O ₃ ) was further added and mixed, and thereafter, a solid catalyst was prepared in the same manner as in Example 1. The solid catalyst thus obtained was subjected to the gas phase catalytic oxidation reaction of propane under the same reaction conditions as in Example 1 except that the reaction temperature was 410 ° C. and the space velocity SV was 19000 h ^−1. It shows in Table-1.

Example 4 Composite oxide 30 prepared as described in Example 1
g was crushed and gallium oxide (Ga ₂ O ₃ ) 0.3 g
Was added and mixed, and thereafter, a solid catalyst was prepared in the same manner as in Example 1. The solid catalyst thus obtained was subjected to the gas phase catalytic oxidation reaction of propane under the same reaction conditions as in Example 1 except that the reaction temperature was 420 ° C. and the space velocity SV was 11000 h ^−1. It shows in Table-1.

Example 5 Composite oxide 30 prepared as described in Example 1
g was crushed, and further yttrium oxide (Y ₂ O ₃ ) 0.3
g was added and mixed, and thereafter, a solid catalyst was prepared in the same manner as in Example 1. The solid catalyst thus obtained was subjected to the gas phase catalytic oxidation reaction of propane under the same reaction conditions as in Example 1 except that the reaction temperature was 430 ° C. and the space velocity SV was 2000 h ^−1. It shows in Table-1.

Example 6 Composite oxide 30 prepared as described in Example 1
g was crushed, and then germanium oxide (GeO ₂ ) 0.3
g was added and mixed, and thereafter, a solid catalyst was prepared in the same manner as in Example 1. The solid catalyst thus obtained was subjected to the gas phase catalytic oxidation reaction of propane under the same reaction conditions as in Example 1, and the results are shown in Table 1.

Example 7 Using the solid catalyst prepared in Example 6, a reaction temperature of 420
Table 1 shows the results of the vapor phase catalytic oxidation reaction of propane under the same reaction conditions as in Example 6 except that the temperature and the space velocity SV were set to 19000 h ^-1 .

Example 8 Composite oxide 30 prepared as described in Example 1
g is crushed, and lead oxide (PbO ) 0.3 g was added and mixed, and thereafter, a solid catalyst was prepared in the same manner as in Example 1. The solid catalyst thus obtained was treated at a reaction temperature of 420
Table 1 shows the results of the gas phase catalytic oxidation reaction of propane under the same reaction conditions as in Example 1 except that the temperature and the space velocity SV were set to 15,000 h ^-1 .

Comparative Example 1 In Example 1, without adding manganese oxide, Mo, V,
Table 1 shows the results obtained by carrying out the reaction under the same conditions as in Example 1 using only the composite oxide composed of Te and Nb.

[0044]

[Table 2]

[0045]

According to the method of the present invention, an alkane is used as a raw material in the presence of a halide, water, etc. in a reaction system, and a high yield is obtained under a relatively low temperature of about 400 to 450 ° C. The nitrile can be produced.

Claims (3)

[Claims] 1. A following formula _{(1) Mo a V b Te} c X x O n (1) ( Formula (1), X is Nb, Ta, W, Ti, A
1, Zr, Cr, Mn, Fe, Ru, Co, Rh, N
Represents one or more elements selected from i, Pd, Pt, Sb, Bi, B, In and Ce, and when a = 1, b = 0.01 to 1.0 c = 0 0.01 to 1.0 x = 0.01 to 1.0, and n is determined by the oxidation states of other elements. In the presence of a solid catalyst obtained by adding one or more oxides of manganese, chromium, gallium, germanium, yttrium and lead to the composite oxide represented by
A method for producing a nitrile, which comprises subjecting an alkane to a gas phase catalytic oxidation reaction with ammonia. 2. The solid catalyst is a substance obtained by adding a composite oxide and one or more oxides of manganese, chromium, gallium, germanium, yttrium and lead and firing the mixture. 1. A method for producing a nitrile of 1. 3. The complex oxide of claim 1, wherein one or more compounds of manganese, chromium, gallium, germanium, yttrium and lead are added and calcined, and the alkane is converted to ammonia in the presence of a solid catalyst. A process for producing a nitrile, characterized in that a gas phase catalytic oxidation reaction is carried out.