JPH0827088A - Method for producing acrylonitrile - Google Patents

Abstract

PURPOSE:To obtain the subject compound in the high reactivity of propylene in high selectivity and in a high yield by subjecting the propylene to a gas phase catalytic ammoxidation reaction in the presence of a specific catalyst. CONSTITUTION:This compound is obtained by subjecting propylene to a gas phase catalytic ammoxidation reaction in the presence of a catalyst having a composition of the formula (X is P, As, B, Ge; Y is Na, K, Rb, Cs, Tl; a, b, c, d, e, f, g, i are the atomic ratios of the respective elements wherein a=10, b=0.1-5, c=0.1-5, d=1-10, e=5.5-20, f=0-3, g=0.01-1.5; and i = the number of oxygen atoms required for satisfying the atomic valencies of the respective components).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing acrylonitrile by vapor-phase catalytic ammoxidation of propylene, and more particularly to molybdenum / bismuth / iron / iron which has a high reactivity of propylene and a high yield of acrylonitrile.
Using magnesium-antimony-containing oxide catalyst,
The present invention relates to a method for producing acrylonitrile by vapor-phase catalytic ammoxidation of propylene.

[0002]

2. Description of the Related Art Conventionally, various proposals have been made regarding catalysts used for producing acrylonitrile by vapor-phase catalytic ammoxidation of propylene. In particular, for molybdenum, bismuth, nickel, and cobalt-based oxide catalysts, many multicomponent catalysts have been proposed. On the other hand, regarding molybdenum, bismuth and magnesium oxide catalysts, JP-A-57-65329, US Pat. No. 4,052,333, and US Pat.
767,878, U.S. Pat. No. 5,212,13.
It can be seen in No. 7 and so on. However, as far as these technical contents are seen, the reaction results of all catalysts are low,
There are problems such as a large decrease in catalyst activity over time, and there are various points to be solved for industrial use.

[0003]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
An object of the present invention is to provide a method for producing acrylonitrile which can be industrially advantageously carried out. Specifically, in a molybdenum-bismuth-magnesium-containing oxide catalyst, a catalyst having good activity and selectivity is used to produce propylene. It is an object of the present invention to provide a method for obtaining acrylonitrile in high yield by vapor-phase catalytic ammoxidation.

[0004]

Means for Solving the Problems As a result of intensive studies aimed at achieving the above object, the present inventors have found that an oxide catalyst obtained by combining molybdenum, bismuth, iron and magnesium with a specific amount of antimony is active and selective. It has been found that it has excellent properties and is useful as an industrial catalyst. The present invention has been achieved based on such knowledge. That is, one of the present invention, in producing acrylonitrile by vapor phase ammoxidation of propylene, is represented by the general formula (1): MoaBibFecMgdSbeXfYgOi (wherein Mo, Bi, Fe, Mg, Sb and O are molybdenum, bismuth, and Represents iron, magnesium, antimony and oxygen, and X is at least one element selected from the group consisting of phosphorus, arsenic, boron and germanium,
Y represents at least one element selected from the group consisting of sodium, potassium, rubidium, cesium and thallium. However, a, b, c, d, e, f, g and i represent the atomic ratio of each element, and when a = 10, b = 0.
1-5, c = 0.1-5, d = 1-10, e = 5.5
20, f = 0 to 3, g = 0.01 to 1.5, and i is the number of oxygen atoms required to satisfy the valence of each component. ) A method for producing acrylonitrile, which comprises using a catalyst having a composition represented by

Another aspect of the present invention is the production of acrylonitrile by vapor-phase catalytic ammoxidation of propylene, wherein MoaBibFecMgdSbeXfYgZhOi represented by the general formula (2) wherein Mo, Bi, Fe, Mg, Sb and O are molybdenum, Represents bismuth, iron, magnesium, antimony and oxygen, X is at least one element selected from the group consisting of phosphorus, arsenic, boron and germanium, Y
Is at least one element selected from the group consisting of sodium, potassium, rubidium, cesium and thallium,
Z represents at least one element selected from the group consisting of nickel, cobalt, zinc, lead, calcium and barium. However, a, b, c, d, e, f, g, h and i
Represents the atomic ratio of each element, and when a = 10, b = 0.
1-5, c = 0.1-5, d = 1-10, e = 5.5
20, f = 0 to 3, g = 0.01 to 1.5, h = 0.1
Is 8 and i is the number of oxygen atoms required to satisfy the valence of each component. ) A method for producing acrylonitrile, which comprises using a catalyst having a composition represented by

The present invention will be specifically described below. An important point in the gas phase catalytic ammoxidation reaction of propylene of the present invention is the catalyst used. The catalyst has the general formula (1)
Alternatively, any catalyst having the composition shown in (2) may be used. In these catalyst compositions, in order to improve the yield of acrylonitrile, a particularly preferable atomic ratio of each component is such that when the molybdenum component a = 10, b = 0.3 to 4,
c = 0.3-4, d = 1.5-9, e = 6-18, f =
0-2, g = 0.03-1.2 and h = 0.3-7. Molybdenum, bismuth, which constitutes the catalyst of the present invention,
It is not sufficiently clear what kind of complex oxide each of iron, magnesium, antimony, and other components forms in the constituent catalyst to contribute to the manifestation of the effect on the activity and selectivity.
However, if the component of the catalyst or the atomic ratio of the component deviates from the range of the general formula, the yield of the target acrylonitrile is lowered, and the physical properties of the catalyst are deteriorated. Therefore, it is presumed that the constituent elements of the catalyst are closely related to each other in order to exert the effect.
In particular, the antimony component is an atomic ratio of molybdenum component 10
On the other hand, when the antimony is in the range of 5.5 to 20, the addition effect is maximized, the desired high yield of acrylonitrile can be obtained, and the physical properties of the catalyst can be improved. It is possible to obtain excellent reproducibility.

The catalyst having the composition represented by the above general formula can be produced by any known method, but it is particularly preferable that the respective components are intimately mixed and integrated. Catalyst Raw Material As a raw material of the element for producing the catalyst, oxide, chloride, sulfate, nitrate, ammonium salt, carbonate, hydroxide, or a mixture thereof which can be converted into an oxide by igniting is selected. You can choose. Examples of the raw material for the molybdenum component include molybdenum oxides such as molybdenum trioxide, molybdic acid, ammonium paramolybdate, ammonium metaparamolybdate, and heteropolyacids containing molybdenum such as phosphomolybdic acid and silicomolybdic acid or the like. Salt or the like is used. Examples of the raw material of the bismuth component include bismuth nitrate, bismuth salts such as bismuth sulfate, bismuth trioxide,
Nitric oxide of metal bismuth is used. As the raw material of the iron component, for example, ferrous oxide, ferric oxide, ferrosoferric oxide, iron nitrate, iron chloride, iron hydroxide, etc. can be used, and metallic iron is dissolved in heated nitric acid. You may use. As the raw material of the magnesium component, for example, magnesium oxide, magnesium hydroxide, magnesium chloride, magnesium nitrate or the like is used. As the raw material of the antimony component, for example, antimony trioxide, antimony tetraoxide, antimony pentaoxide, antimonic acid, polyantimonic acid, sodium antimonate, potassium antimonate, antimony trichloride, antimony pentachloride, etc. are used. As the raw materials for the other X component, Y component and Z component, oxides, hydroxides, nitrates, carbonates, organic acid salts and the like of the respective elements are used.

Preparation of Catalyst The catalyst of the present invention can be produced by intimately mixing these catalyst raw materials so as to have a desired atomic ratio, drying and then calcining. Here, the calcination conditions are important in order to impart a predetermined activity to the catalyst. Catalyst is 2
In the temperature range of 00 to 800 ° C, preferably 400 to 75
It is preferable to heat in the temperature range of 0 ° C. for 0.5 to 10 hours. The gas atmosphere used at this time is not a particularly important factor. That is, sufficient catalytic performance can be obtained even in an oxidizing gas atmosphere containing oxygen, for example, in a reducing gas atmosphere containing only nitrogen. A tunnel furnace, a rotary furnace, a fluidized furnace, or the like can be used for firing.

The catalyst of the present invention can be used without a carrier, but may be used in combination with a suitable carrier. In this case, the support can be varied in any proportion up to 10-90% by weight of the total catalyst weight. As the carrier, silica,
Alumina, zirconia, magnesia, titania, silica-alumina, etc. can be used. The size and shape of the catalyst is
It is possible to use pellets, tablets, spheres, granules, or any other shape and size depending on the state of use of the catalyst.

Reaction Method The method of the present invention can be carried out in a fixed bed or a fluidized bed. It is carried out by supplying propylene, ammonia, oxygen and the like to the reactor filled with the catalyst manufactured as described above. Air is preferred as the oxygen source for economic reasons. The air may be suitably enriched with oxygen. The molar ratio of oxygen / propylene in the raw material supplied to the reactor is in the range of 1 to 4, but since the catalyst of the present invention has a high acrylonitrile selectivity, it has a relatively low molar ratio of 1.5 to 2.5. The range is good. The ammonia / propylene molar ratio in the raw material supplied to the reactor was 0.
It can be increased or decreased within the range of 8 to 3, but 0.9 to 1.
A range of 5 is preferred. Also, if necessary, an inert gas,
For example, nitrogen, steam or the like may be supplied. The reaction temperature is preferably in the range of 380 to 500 ° C, particularly preferably in the range of 400 to 480 ° C. The reaction pressure is appropriately in the range of atmospheric pressure to 5 atm.

[0011]

EXAMPLES The method for producing the catalyst according to the present invention and the reaction examples using the same are specifically described below, but the present invention is not limited to these examples. The activity test of the catalyst is as follows. A catalyst was packed in a fluidized bed reactor having an inner diameter of the catalyst fluidized portion of 25 mmφ and a height of 400 mm, and a gas having the following composition was fed. The reaction pressure is normal pressure. Oxygen (supplied by air) /propylene=2.0 (mol / mol), ammonia / propylene = 1.3 (mol / mol) In the examples, the propylene conversion rate and the acrylonitrile yield are defined as follows. Parts in the following Examples and Comparative Examples are parts by weight, and analysis was by gas chromatography.

Example 1 The composition of elements other than oxygen in the catalyst (hereinafter the same) is Mo ₁₀ B
A catalyst that was i ₁ Fe ₂ Mg ₆ Sb ₆ P _0.3 K _0.2 Si ₆₀ was prepared as follows. To 2000 parts of pure water, 500 parts of ammonium paramolybdate was added and heated and stirred. To this, 228.8 parts of ferric nitrate dissolved in 230 parts of pure water was added to form a slurry. Further, 9.8 parts of 85% phosphoric acid and antimony tetroxide 261.3 dissolved in 20 parts of pure water.
Parts were added and stirred (solution A). Separately, 60 parts in 1200 parts of pure water
After adding 84.1 parts of% nitric acid to make the mixture uniform, 137.4 parts of bismuth nitrate was added and dissolved. To this, 435.7 parts of magnesium nitrate was added and dissolved (solution B). Liquid B was added to liquid A to form a slurry, and 3.2 parts of potassium hydroxide dissolved in 20 parts of pure water and 5104.9 parts of 20% silica sol were sequentially added and heated and stirred. The thus-obtained slurry was spray-dried by a rotary disk type spray dryer controlled at an inlet temperature of 320 ° C. and an outlet temperature of 160 ° C. The obtained catalyst was heat-treated at 250 ° C., further calcined at 400 ° C. for 2 hours, and finally calcined at 600 ° C. for 3 hours.

Examples 2 to 6 Catalysts having the compositions shown in Examples 2 to 6 in Table 1 were produced according to the method of Example 1.

Example 7 A catalyst having the composition shown in Example 7 of Table 1 was produced according to the method of Example 1. However, boric acid is added next to phosphoric acid,
Further, cobalt nitrate was added next to magnesium nitrate and dissolved.

Examples 8 to 14 Catalysts having the compositions shown in Examples 8 to 14 in Table 1 were produced according to the method of Example 7.

Comparative Example 1 The composition of elements other than oxygen in the catalyst was Mo ₁₀ Bi ₃ Fe ₅ Sb.
_A comparative catalyst, ₆ P _0.3 K _0.2 Si ₆₀ , was prepared as follows. To 2000 parts of pure water, 500 parts of ammonium paramolybdate was added and heated and stirred. To this, 572.1 parts of ferric nitrate dissolved in 580 parts of pure water was added to form a slurry. Furthermore, 85% phosphoric acid dissolved in 20 parts of pure water 9.
8 parts and 261.3 parts of antimony tetroxide were added and stirred (solution A). Separately, 2000 parts of pure water and 252.3 of 60% nitric acid
After adding 1 part to homogenize, 412.1 parts of bismuth nitrate were added and dissolved (solution B). Solution B was added to solution A to form a slurry, and then potassium hydroxide 3.2 dissolved in 20 parts of pure water was used.
Parts and 5104.9 parts of 20% silica sol were sequentially added and heated and stirred. A catalyst was produced according to the method of Example 1 except for the above.

Comparative Example 2 A catalyst having the composition shown in Comparative Example 2 in Table 2 was produced according to the method of Example 1. However, antimony tetroxide was not added.

Comparative Example 3 A catalyst having the composition shown in Comparative Example 3 in Table 2 was produced according to the method of Example 1. However, the amount of antimony tetroxide added was changed to 174.2 parts.

Comparative Example 4 A catalyst having the composition shown in Comparative Example 4 in Table 2 was produced according to the method of Example 1. However, the amount of antimony tetroxide added was changed to 1741.7 parts.

The results of the activity test using the catalysts of the above Examples and Comparative Examples are shown in Table 1 and Table 2, respectively.

[0021]

[Table 1]

[0022]

[Table 2]

[0023]

The catalyst containing molybdenum / bismuth / iron / magnesium / antimony / alkali metal according to the present invention is excellent in the reaction activity of propylene and the yield of acrylonitrile in the reaction for producing acrylonitrile from propylene. Has performance. Therefore, according to the method of the present invention, the production of acrylonitrile by vapor-phase catalytic ammoxidation of propylene can be industrially advantageously carried out as compared with the conventional method.

Claims (2)

[Claims] 1. When producing acrylonitrile by vapor-phase catalytic ammoxidation of propylene, MoaBibFecMgdSbeXfYgOi (wherein Mo, Bi, Fe, Mg, Sb and O are molybdenum, bismuth, iron, magnesium and antimony, respectively) are used. And oxygen, X is at least one element selected from the group consisting of phosphorus, arsenic, boron and germanium, Y
Represents at least one element selected from the group consisting of sodium, potassium, rubidium, cesium and thallium. However, a, b, c, d, e, f, g and i represent the atomic ratio of each element, and when a = 10, b = 0.1.
-5, c = 0.1-5, d = 1-10, e = 5.5-2
0, f = 0 to 3, g = 0.01 to 1.5, and i is the number of oxygen atoms required to satisfy the valence of each component. ) A method for producing acrylonitrile, which comprises using a catalyst having a composition represented by 2. When acrylonitrile is produced by vapor-phase catalytic ammoxidation of propylene, MoaBibFecMgdSbeXfYgZhOi represented by the general formula (2) (wherein Mo, Bi, Fe, Mg, Sb and O are molybdenum, bismuth, iron, magnesium and antimony, respectively). And oxygen, X is at least one element selected from the group consisting of phosphorus, arsenic, boron and germanium, Y
Is at least one element selected from the group consisting of sodium, potassium, rubidium, cesium and thallium,
Z represents at least one element selected from the group consisting of nickel, cobalt, zinc, lead, calcium and barium. However, a, b, c, d, e, f, g, h and i
Represents the atomic ratio of each element, and when a = 10, b = 0.
1-5, c = 0.1-5, d = 1-10, e = 5.5
20, f = 0 to 3, g = 0.01 to 1.5, h = 0.1
Is 8 and i is the number of oxygen atoms required to satisfy the valence of each component. ) A method for producing acrylonitrile, which comprises using a catalyst having a composition represented by