JP2000351760A - Method for producing unsaturated nitrile - Google Patents

Abstract

(57) Abstract: A process for producing acrylonitrile or methacrylonitrile from a saturated aliphatic hydrocarbon, propane or isobutane, in a high yield is provided. SOLUTION: Propane or isobutane is subjected to an ammoxidation reaction in the presence of a catalyst composition containing oxides of iron, antimony, chromium and molybdenum as essential components to obtain acrylonitrile or methacrylonitrile.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing an unsaturated nitrile. More particularly, the present invention relates to a method for producing acrylonitrile or methacrylonitrile from propane or isobutane which is a saturated aliphatic hydrocarbon.

[0002]

2. Description of the Related Art Unsaturated nitriles such as acrylonitrile and methacrylonitrile are industrially produced as important intermediates such as synthetic fibers, synthetic resins and synthetic rubbers. Conventionally, acrylonitrile has been produced by ammoxidation of propylene, and methacrylonitrile has been produced by ammoxidation of isobutene. However, in recent years, attention has been paid to a method for producing propane or isobutane by ammoxidation, which is cheaper than propylene and isobutene, and various catalysts have been proposed.

[0003] For example, Sb-V catalysts (British Patent 1,3
No. 66,135), a Fe-U-Sb-based catalyst (U.S. Pat. No. 3,686,295), a VP-based catalyst (Japanese Patent Publication No. 58-5188), and a Bi-V-based catalyst (Japanese Unexamined Patent Publication No. 63
295545), V-Sb-based catalyst and Fe-Sb
-Based catalyst mixture (JP-A-63-295546),
Mo-V-Te-Nb-based catalysts (JP-A-2-257), (Nb, Ta) -Mo-Bi-Cr-based catalysts (JP-A-6-257)
-116225), a Cr-Sb-W-based catalyst (JP-A-7-157461), a Mo-Sb-W-based catalyst (JP-A-7-157462), a Mo-V-Sb-based catalyst (JP-A-7-157462). 9-157241), Mo-Sb-
Cr-based catalyst (JP-A-10-43586), Mo-
Sb- (Fe, Ga, Zn, Co, Mn) -based catalyst (JP-A-10-43587), W-Cr-Bi-based catalyst (JP-A-10-87513), Mo-Cr-Bi
-Fe-based catalyst (JP-A-10-195036), M
o- (Bi, Te) -Cr-based catalyst (JP-A-11-993)
No. 34) has been reported.

[0004]

In the production of unsaturated nitriles by ammoxidation of saturated hydrocarbons, despite the many studies described above, the target yield is still low. Attempts have also been made to increase the yield of nitriles by adding a small amount of organic halides, inorganic halides, and sulfur compounds to the reaction system. There is a drawback that it is difficult to implement it. Development of a catalyst for efficiently performing ammoxidation of propane or isobutane without using a corrosive halogen promoter or the like has been an important issue in the art.

[0005]

The present inventors have conducted intensive studies on a novel catalyst for producing acrylonitrile or methacrylonitrile by using propylene or isobutene as a raw material. As a result, the present inventors have found that a new catalyst of the Fe-Sb-Cr-Mo-X type is used. By carrying out ammoxidation in the presence of a metal oxide (X represents one or more specific elements), the desired unsaturated nitrile can be efficiently produced without the presence of a halogen promoter in the reaction system. As a result, the present invention has been completed.

That is, the present invention relates to a process for producing acrylonitrile or methacrylonitrile, which comprises subjecting propane or isobutane to an ammoxidation reaction in the presence of a catalyst composition represented by the following empirical formula. FeasSbbCrcModQeOf (where Fe is iron, Sb is antimony, Cr is chromium, Mo is molybdenum, Q is Li, Na, K, Rb, C
s, Be, Mg, Ca, Sr, Ba, Sc, Y, La,
Ce, Pr, Nd, Sm, Th, U, Ti, Zr, H
f, Nb, Ta, W, V, Mn, Re, Co, Ni, R
u, Rh, Pd, Os, Ir, Pt, Cu, Ag, A
u, Zn, Cd, Hg, Al, Ga, In, Tl, G
e, Sn, Pb, P, B, As, Bi, Se, and at least one element selected from the group consisting of Te, and subscripts a, b, c, d, e, and f indicate atomic ratios, It is in the following range. a = 5 to 15, preferably 7 to 12 b = 5 to 100, preferably 5 to 50 c = 0.01 to 15, preferably 0.1 to 10 d = 0.01 to 15, preferably 0.1 10 to 10 e = 0 to 15, preferably 0 to 10 f = a number corresponding to the oxide formed by combining the above components. )

[0007]

Embodiments of the present invention will be described below in detail. Iron which is a component of the catalyst composition used in the present invention,
It is particularly important that the atomic ratio of antimony, chromium, and molybdenum is within the above range in order to obtain the target compound in a high yield, and when the ratio is outside this range, the yield of the target product is significantly reduced. .

The Q component of the catalyst composition used in the present invention can be added for the purpose of improving physical properties, making it suitable, adjusting the reaction rate, improving the selectivity, and the like. Affects.

[0009] The catalyst composition used in the present invention preferably has a specific crystal structure, specifically, iron antimonate as a crystal phase. Examples of iron antimonates include FeSbO4, FeSb2 O4, and FeSb2.
Several types such as O6 are known, and any of these types can be used in the catalyst composition of the present invention. Usually, FeSbO4 is the most common, for which also X-ray diffraction data is described, for example, in J. Mol. Kori
nth, P.N. Royen, Z .; Anorg. allg.
Chem. , 340 , 146-157 (1965). The presence or absence of crystalline iron antimonate in the catalyst composition used in the present invention can be confirmed by X-ray diffraction.

[0010] The crystalline iron antimonate referred to in the present invention includes not only pure iron antimonate but also a solid solution of various elements. Further, all of the iron component and the antimony component do not necessarily have to form crystalline iron antimonate, and there is no problem even if some iron components or antimony components are present in an amorphous state. , May form another compound.

In the catalyst composition used in the present invention, chromium,
Molybdenum and other optional components may be present in any form, but will often be in a form of solid solution with iron antimonate.

In preparing the catalyst composition used in the present invention, various preparation methods can be used. The aqueous slurry containing iron antimonate and the raw material compound of the chromium component prepared in advance is spray-dried and calcined. It is preferably manufactured. For fixed bed catalysts, spray drying,
After firing, it is molded and used. In the case of a fluidized bed catalyst, it is spray-dried so as to have a desired particle size distribution and then calcined.

As a method which is industrially easy to carry out, there is a method described in JP-A-4-126548 or the like, or a method analogous thereto. For example, after adjusting the pH of the slurry containing iron nitrate and antimony oxide to 1 to 4, about 8
An iron antimonate is generated in the system by performing a heat treatment at a temperature of 0 to 120 ° C., and thereafter, an aqueous slurry obtained by adding a raw material compound of a chromium component is spray-dried,
Next, firing is performed. When the raw material compound of the chromium component is mixed simultaneously with, for example, iron nitrate and antimony oxide, not only the yield of the target product is lowered, but also the physical properties of the catalyst, particularly the strength, are lowered, and it cannot be put to practical use.

[0014] The component materials other than iron, antimony and chromium can be added in a small amount in any step of the production process, but preferably mixed with iron antimonate prepared in advance.

The starting materials for each component constituting the catalyst composition used in the present invention are not particularly limited as long as they contain each component, and include oxides, hydroxides, nitrates, and the like. Can be arbitrarily selected and used. For example, raw materials for iron components include metallic iron, iron oxide,
Iron nitrate, iron acetate, iron oxalate, etc., as the raw material of the antimony component, antimony oxide, products obtained by nitric acid oxidation of antimony metal, etc., as the raw material of the chromium component, chromium oxide, chromium nitrate, etc. As a raw material of the molybdenum component, molybdenum oxide, ammonium molybdate, or the like can be used. The other materials for the Q component and the R component can be arbitrarily selected from many types such as oxides, hydroxides, chlorides, and nitrates of the respective component elements.

The catalyst composition used in the present invention can be used as it is. However, it is preferable to use the catalyst composition supported on a suitable carrier in order to increase the surface area of the catalyst or to improve physical properties such as mechanical strength. Can also. Preferred examples of the carrier include silica, alumina, titania, zirconia and the like, and each may be used alone or a mixture thereof. The carrier is 10-90 of the total catalyst weight.
It can be changed arbitrarily within the range of weight%. As the carrier raw material, sol, gel, oxide powder or the like can be used.

The spray drying in the preparation of the catalyst used in the present invention may be performed by any method such as a rotary disk type and a high pressure nozzle type. When used as a fluidized bed catalyst, the spray drying conditions are set so that the particle size distribution of the catalyst after the final calcination is in the range of 10 to 200 μm. Then 200-9
Bake at 00 ° C for 0.5 to 20 hours. The calcination can be performed in an atmosphere of air, oxygen, nitrogen, carbon dioxide, or the like, or a mixed gas atmosphere thereof, and can be arbitrarily selected depending on the purpose. The final baking may be performed in air, but is preferably performed in an atmosphere of an inert gas such as nitrogen, helium, carbon dioxide, or the like, or in a mixed gas atmosphere of air and a reducing gas. The firing temperature is preferably 400 to 900 ° C,
Perform for 0 hours.

The form of the catalyst used in the present invention is not particularly limited. In the case of a fluidized bed catalyst, it is usually used as it is after calcination. In the case of a fixed-bed catalyst, it is formed into a desired size by a method such as tableting, extrusion molding, or granulation after drying or baking, and is used in the form of a pellet, ring, sphere, or the like.

The reaction gas composition used in the reaction of the present invention is such that ammonia is added to propane or isobutane per mole of ammonia.
3-5 mol, oxygen 0.2-5 mol, and nitrogen, water vapor, carbon dioxide, etc. may be added as a diluting gas. It is convenient and economically preferable to use air as a source of oxygen.

The reaction pressure used in the present invention can be carried out near atmospheric pressure, or under a slight pressure or at a normal pressure. The reaction temperature is in the range of 400C to 600C, preferably in the range of 420C to 550C. Contact time is 0.1 ~
The range is 30 seconds. In addition, fixed bed, fluidized bed,
Any of the moving layers may be used.

[0021]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. Note that items common to each example and comparative example are as follows. The activity test used a fluidized bed reactor having an inner diameter of 3/4 inch. The contact time, the conversion of propane or isobutane, the selectivity and yield of the desired product (acrylonitrile or methacrylonitrile) are defined as follows. Contact time = catalyst volume (l) / feed gas flow rate under reaction conditions (l / sec) Conversion of propane or isobutane (%) = [moles of propane or isobutane consumed] / [moles of propane or isobutane supplied] Number] × 100 Selectivity (%) of target product = [moles of target product generated] / [moles of propane or isobutane consumed]
× 100 Yield (%) of target product = [moles of target product generated] / [moles of supplied propane or isobutane] ×
100 The subscript X of oxygen in each catalyst composition formula is a value naturally determined by the valence of another element.

Example 1 The composition is Fe10Sb20Cr2Mo2OX (SiO2) 5
The catalyst designated as 0 was prepared in the following manner. (I) 251.9 g of antimony trioxide powder was taken. (II) 390 ml of nitric acid (specific gravity 1.38) and 490 m of pure water
and heated, and 48.0 g of electrolytic iron was gradually added and dissolved therein. (III) Silica sol (SiO2: 20% by weight) 129
0.8 g. (IV) 12.2 g of ammonium paramolybdate was dissolved in 50 ml of pure water. (V) 68.8 g of chromium nitrate nonahydrate was dissolved in 150 g of pure water. (II) was added to (III) and (I) in this order with good stirring, and adjusted to pH 2 with 15% aqueous ammonia. This slurry was heated at 98 ° C. for 3 hours while stirring.
Thereafter, (IV) and (V) were added with good stirring, and the aqueous slurry thus obtained was spray-dried using a rotary disk type spray-drying apparatus. The obtained fine spherical particles were fired at 200 ° C. for 2 hours and 400 ° C. for 3 hours in an air atmosphere, and further fired at 750 ° C. for 2 hours in a nitrogen atmosphere. When a powder X-ray diffraction measurement of the catalyst thus obtained was performed, a diffraction pattern corresponding to FeSbO4 was observed. This catalyst was charged in a reactor, and propane ammoxidation reaction was performed at a molar ratio of propane: ammonia: air = 1: 1.2: 15. Table 1 shows the results.

Example 2 The composition is Fe10Sb20Cr4Mo2OX (SiO2) 5
The catalyst represented by 0 was prepared in the same manner as in Example 1 except that 137.6 g of chromium nitrate nonahydrate was dissolved in 300 g of pure water. Using this catalyst, propane ammoxidation was carried out in the same manner as in Example 1. Table 1 shows the results.

Example 3 The composition is Fe10Sb20Cr6Mo2OX (SiO2) 5
The catalyst represented by 0 was prepared in the same manner as in Example 1 except that 206.4 g of chromium nitrate nonahydrate was dissolved in 450 g of pure water. Using this catalyst, propane ammoxidation was carried out in the same manner as in Example 1. Table 1 shows the results.

Example 4 The composition is Fe10Sb20Cr4Mo4OX (SiO2) 5
The catalyst represented by 0 is ammonium paramolybdate 1
Preparation was carried out in the same manner as in Example 2 except that 2.2 g was dissolved in 50 ml of pure water, and finally baked at 740 ° C. for 2 hours in a nitrogen atmosphere. Using this catalyst, propane ammoxidation was carried out in the same manner as in Example 1. Table 1 shows the results.

Example 5 The composition is Fe10Sb20Cr4Mo4Nb0.5OX
An aqueous solution of ammonium niobium oxalate and an aqueous solution of ammonium metavanadate at the same time
(Nb ₂ O ₅ , 5 wt%) Preparation was carried out in the same manner as in Example 4 except that 114.2 g was added. Using this catalyst, propane ammoxidation was carried out in the same manner as in Example 1. Table 1 shows the results.

Example 6 The composition was Fe10Sb20Cr4Mo4V2OX (SiO
2) The same process as in Example 4 except that the catalyst represented by 50 was added simultaneously with an aqueous solution of chromium nitrate and 20.1 g of ammonium metavanadate was added to 120 g of pure water and heated, and a solution in which 40 g of oxalic acid was gradually added and dissolved was added. Preparation was performed by the method, and finally calcination was performed at 720 ° C. for 2 hours in a nitrogen atmosphere. Using this catalyst, propane ammoxidation was carried out in the same manner as in Example 1. Table 1 shows the results.

Example 7 The composition is Fe10Sb40Cr2Mo4OX (SiO2) 5
503.8 g of antimony trioxide powder as a catalyst represented by 0
Take and 24.4 g of ammonium paramolybdate
Was prepared in the same manner as in Example 1 except that was dissolved in 100 ml of pure water. Using this catalyst, propane ammoxidation was carried out in the same manner as in Example 1. Table 1 shows the results.

Example 8 The composition was Fe10Sb10Cr0.5Mo1OX (SiO
2) using a catalyst represented by 50 as antimony trioxide powder 12
Ammonium paramolybdate 6.1 g, weighing 6.0 g
g of chromium nitrate nonahydrate 1 dissolved in 25 ml of pure water
Preparation was performed in the same manner as in Example 1 except that 7.2 g was dissolved in 40 g of pure water. Example 1 using this catalyst
Ammoxidation reaction of propane was performed in the same manner as in 1. Table 1 shows the results.

Comparative Example 1 A catalyst having a composition represented by Fe10Sb20Cr2OX (SiO2) 50 was prepared in the same manner as in Example 1 except that an aqueous solution of ammonium paramolybdate was not added. Using this catalyst, propane ammoxidation was carried out in the same manner as in Example 1. Table 1 shows the results.

Comparative Example 2 A catalyst having a composition represented by Fe10Sb20Cr6OX (SiO2) 50 was prepared in the same manner as in Example 3 except that an aqueous solution of ammonium paramolybdate was not added. Using this catalyst, propane ammoxidation was carried out in the same manner as in Example 1. Table 1 shows the results.

Comparative Example 3 A catalyst having a composition of Fe10Sb20Mo2OX (SiO2) 50 was prepared in the same manner as in Example 1 except that an aqueous solution of chromium nitrate was not added, and finally an air atmosphere at 700 ° C. for 2 hours. Was fired. Using this catalyst, propane ammoxidation was carried out in the same manner as in Example 1. Table 1 shows the results.

[0033]

[Table 1]

[0034]

According to the catalyst produced by the method of the present invention,
The target acrylonitrile or methacrylonitrile can be produced in high yield from propane or isobutane as a raw material.

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Claims (3)

[Claims] 1. A process for producing acrylonitrile or methacrylonitrile, wherein an ammoxidation reaction of propane or isobutane is carried out in the presence of a catalyst composition represented by the following empirical formula. FeasSbbCrcModQeOf (where Fe is iron, Sb is antimony, Cr is chromium, Mo is molybdenum, Q is Li, Na, K, Rb, C
s, Be, Mg, Ca, Sr, Ba, Sc, Y, La,
Ce, Pr, Nd, Sm, Th, U, Ti, Zr, H
f, Nb, Ta, W, V, Mn, Re, Co, Ni, R
u, Rh, Pd, Os, Ir, Pt, Cu, Ag, A
u, Zn, Cd, Hg, Al, Ga, In, Tl, G
e, Sn, Pb, P, B, As, Bi, at least one element selected from the group consisting of Se and Te, and subscripts a, b, c, d, e and f indicate atomic ratios, It is in the following range. a = 5 to 15 b = 5 to 100 c = 0.01 to 15 d = 0.01 to 15 e = 0 to 15 f = a number corresponding to an oxide formed by combining the above components. ) 2. The method according to claim 1, wherein the catalyst composition contains iron antimonate as a crystalline phase. 3. The catalyst composition is prepared by preparing an iron antimonate in advance, preparing an aqueous slurry containing the iron antimonate and a raw material compound of a chromium component, and then spray drying and calcining the slurry. 3. The method according to claim 1, wherein: