WO2020039985A1

WO2020039985A1 - Method for producing ammoxidation catalyst, and method for producing acrylonitrile

Info

Publication number: WO2020039985A1
Application number: PCT/JP2019/031717
Authority: WO
Inventors: 孝平守屋; 章喜福澤
Original assignee: 旭化成株式会社
Priority date: 2018-08-24
Filing date: 2019-08-09
Publication date: 2020-02-27
Also published as: TWI710404B; TW202015806A

Abstract

The purpose of the present invention is to provide a method for producing an ammoxidation catalyst which enables synthesizing acrylonitrile with high yield. This method for producing an ammoxidation catalyst involves a preparation step for preparing a precursor slurry that will become the catalyst precursor, a drying step for drying the precursor slurry to obtain dry particles, and a firing step for firing the dry particles to obtain an ammoxidation catalyst, wherein the calorific value of the dried particles prior to firing, calculated from the area value of the exothermic peaks that have a maximum value in the range from 200°C to 300°C observed with TG-DTA measurement, is 45-200 J/g.

Description

Method for producing catalyst for ammoxidation and method for producing acrylonitrile

The present invention relates to a method for producing an oxide catalyst, and a method for producing acrylonitrile using an oxide catalyst produced by the method.

方法 The method of producing acrylonitrile by reacting molecular oxygen with propylene and ammonia is widely known as “ammoxidation reaction”, and is currently practiced on an industrial scale. In this reaction, a composite oxide catalyst is used to achieve a good acrylonitrile yield. For example, catalysts containing Mo-Bi-Fe or Fe-Sb as an essential component are used industrially, and studies are being made on improving the metal composition to achieve a better acrylonitrile yield ( For example, refer to Patent Documents 1 and 2).

On the other hand, even if the metal composition is common, attempts have been made to improve the acrylonitrile yield by devising a catalyst preparation method. For example, Patent Literature 3 discloses a method for preparing an ammoxidation catalyst containing molybdenum, bismuth, and iron as essential components, in which a coordinating organic compound is added to a raw material slurry. Further, Patent Document 4 discloses that in the process of preparing an ammoxidation catalyst containing molybdenum, bismuth, and iron as essential components, a thermally decomposable nitrogen compound (containing no metal, ammonium compound, nitrate compound, nitrite compound, amide compound, A nitrobenzoic acid compound and an ammonium hydroxide compound).

In addition to the method of adding an additive during the catalyst preparation process, for example, Patent Literature 5 discloses a method of adjusting the pH of a slurry containing a catalyst component to a predetermined range, and Patent Literature 6 discloses a method in which the slurry is subjected to specific conditions during the process. A method of holding for a certain period of time is disclosed below. Further, for example, Patent Document 7 discloses a method for producing a catalyst for producing acrylonitrile, in which the temperature of a slurry containing molybdenum, bismuth, iron, tungsten and the like is adjusted to a range of 30 to 70 ° C.

Patent No. 5491037 JP-A-11-246504 Patent No. 6118016 JP-T-2015-536821A Patent No. 4159759 Patent No. 4425743 JP 2008-237963 A

However, from the viewpoint of improving the yield of acrylonitrile, these catalyst production methods have been improved to some extent, but are still not sufficient, and further improvement is desired. The present invention has been made in view of the above circumstances, and has as its object to provide a method for producing an ammoxidation catalyst capable of synthesizing acrylonitrile with high yield.

者 The present inventors have paid attention to the state of dry particles obtained by drying a slurry containing a catalyst component, based on the fact that catalyst performance is not always the same even when the composite oxides have the same metal composition. As a result, a correlation was found between the calorific value when firing the dried particles and the final catalyst performance (acrylonitrile yield), and the present invention was completed.

That is, the present invention is as follows.
[1]
A preparation step of preparing a precursor slurry to be a catalyst precursor,
A drying step of drying the precursor slurry to obtain dry particles,
A firing step of firing the dried particles to obtain an ammoxidation catalyst,
Has,
The calorific value calculated from the area value of the exothermic peak having a maximum value in the range of 200 ° C. to 300 ° C. observed by TG-DTA measurement of the dried particles before firing is 45 J / g or more and 200 J / g or less. And a method for producing an ammoxidation catalyst.
[2]
The method for producing an ammoxidation catalyst according to [1], wherein the calorific value is 80 J / g or more and 200 J / g or less.
[3]
The method for producing an ammoxidation catalyst according to [1] or [2], wherein the ammoxidation catalyst includes a composite metal oxide having a composition represented by the following general formula (1).
_{_{_{_{Mo 12 Bi a Fe b X c}}}} Y d Z e O f (1)
(In the formula (1), X is one or more elements selected from the group consisting of nickel, cobalt, magnesium, calcium, zinc, strontium, and barium, and Y is cerium, chromium, lanthanum, neodymium, yttrium, praseodymium, samarium, Z represents one or more elements selected from the group consisting of potassium, rubidium and cesium, and a represents the atomic ratio of bismuth to 12 atoms of molybdenum. 0.1 ≦ a ≦ 2.0, b represents the atomic ratio of iron to 12 atoms of molybdenum, 0.1 ≦ b ≦ 3.0, and c represents the atomic ratio of X to 12 atoms of molybdenum. 0.1 ≦ c ≦ 10.0, d represents the atomic ratio of Y to 12 molybdenum atoms, and 0.1 ≦ d ≦ 3. 0, e indicates the atomic ratio of Z to 12 atoms of molybdenum, 0.01 ≦ e ≦ 2.0, f indicates the atomic ratio of oxygen to 12 atoms of molybdenum, and the valence of other elements present This is the number of oxygen atoms required to satisfy the requirement.)
[4]
The method for producing an ammoxidation catalyst according to any one of [1] to [3], wherein the ammoxidation catalyst contains a carrier, and the content of the carrier in the ammoxidation catalyst is 35 to 45% by mass.
[5]
The method for producing an ammoxidation catalyst according to any one of [1] to [4], wherein the preparation step of preparing the precursor slurry includes adding aqueous ammonia or water to the raw material.
[6]
The catalyst for ammoxidation according to any one of [1] to [5], wherein in the preparation step of preparing the precursor slurry, the raw material includes a molybdenum solution, and includes adding ammonia water or water to the molybdenum solution. Production method.
[7]
In the drying step of drying the precursor slurry to obtain dried particles, the inlet air temperature of the dryer is maintained at 180 to 280 ° C and the outlet temperature is maintained at 100 to 170 ° C. A method for producing the ammoxidation catalyst according to any one of the above.
[8]
In the firing step of firing the dried particles to obtain an ammoxidation catalyst, a denitration treatment is performed before the main firing, and the denitration treatment is performed by heating at 150 to 450 ° C. for 1.5 to 3 hours, [1] to The method for producing an ammoxidation catalyst according to any one of [7].
[9]
The method for producing an ammoxidation catalyst according to any one of [1] to [8], wherein in the firing step of firing the dried particles to obtain an ammoxidation catalyst, the main firing temperature is 550 to 650 ° C.
[10]
A preparation step of preparing a precursor slurry to be a catalyst precursor,
A drying step of drying the precursor slurry to obtain dry particles,
A firing step of firing the dried particles to obtain an ammoxidation catalyst,
The step of supplying the catalyst for ammoxidation in advance to a fluidized reaction vessel and, while circulating the catalyst in the fluidized reaction vessel, reacting propylene, molecular oxygen, and ammonia to obtain acrylonitrile,
The calorific value calculated from the area value of the exothermic peak having a maximum value in the range of 200 ° C. to 300 ° C. observed by TG-DTA measurement of the dried particles before firing is 45 J / g or more and 200 J / g or less. And a method for producing acrylonitrile.
[11]
The method for producing acrylonitrile according to [10], wherein the calorific value is 80 J / g or more and 200 J / g or less.
[12]
The source of molecular oxygen is air;
[10] or [11], wherein the molar ratio of ammonia and air to propylene is in the range of 1 / (0.8 to 1.4) / (7 to 12) in the ratio of propylene / ammonia / air. A method for producing acrylonitrile.
[13]
The source of molecular oxygen is air;
The method according to [10] or [11], wherein the molar ratio of ammonia and air to propylene is in the range of 1 / (0.9 to 1.3) / (8 to 11) in the ratio of propylene / ammonia / air. A method for producing acrylonitrile.
[14]
The acrylonitrile according to any one of [10] to [13], wherein a temperature at which propylene, molecular oxygen, and ammonia are reacted in the presence of the ammoxidation catalyst is in a temperature range of 350 to 550 ° C. Manufacturing method.
[15]
The acrylonitrile according to any one of [10] to [13], wherein a temperature at which propylene, molecular oxygen, and ammonia are reacted in the presence of the ammoxidation catalyst is in a temperature range of 400 to 500 ° C. Manufacturing method.
[16]
The method for producing acrylonitrile according to any one of [10] to [15], wherein the ammoxidation catalyst contains a composite metal oxide having a composition represented by the following general formula (1).
_{_{_{_{Mo 12 Bi a Fe b X c}}}} Y d Z e O f (1)
(In the formula (1), X is at least one element selected from the group consisting of nickel, cobalt, magnesium, calcium, zinc, strontium, and barium, and Y is cerium, chromium, lanthanum, neodymium, yttrium, praseodymium, samarium, Z represents one or more elements selected from the group consisting of potassium, rubidium and cesium, and a represents the atomic ratio of bismuth to 12 molybdenum atoms. 0.1 ≦ a ≦ 2.0, b represents the atomic ratio of iron to 12 atoms of molybdenum, 0.1 ≦ b ≦ 3.0, and c represents the atomic ratio of X to 12 atoms of molybdenum. 0.1 ≦ c ≦ 10.0, d represents the atomic ratio of Y to 12 molybdenum atoms, and 0.1 ≦ d ≦ 3 0, e indicates the atomic ratio of Z to 12 atoms of molybdenum, 0.01 ≦ e ≦ 2.0, f indicates the atomic ratio of oxygen to 12 atoms of molybdenum, and the valence of other elements present The number of oxygen atoms required to satisfy the requirement.)
[17]
The method for producing acrylonitrile according to any one of [10] to [16], wherein the catalyst for ammoxidation contains a carrier, and the content of the carrier in the catalyst for ammoxidation is 35 to 45% by mass.
[18]
The method for producing acrylonitrile according to any one of [10] to [17], wherein the step of preparing the precursor slurry includes adding ammonia water or water to the raw material.
[19]
The method for producing acrylonitrile according to any one of [10] to [18], wherein in the preparation step of preparing the precursor slurry, the raw material includes a molybdenum solution, and the method includes adding ammonia water or water to the molybdenum solution.
[20]
In the drying step of drying the precursor slurry to obtain dried particles, the inlet air temperature of the dryer is maintained at 180 to 280 ° C. and the outlet temperature is maintained at 100 to 170 ° C. [10] to [19]. The method for producing acrylonitrile according to any one of the above.
[21]
In the firing step of firing the dried particles to obtain an ammoxidation catalyst, a denitration treatment is performed before the main firing, and the denitration treatment is performed by heating at 150 to 450 ° C. for 1.5 to 3 hours, [10] to The method for producing acrylonitrile according to any one of [20].
[22]
The method for producing acrylonitrile according to any one of [10] to [21], wherein in the firing step of firing the dried particles to obtain an ammoxidation catalyst, the main firing temperature is 550 to 650 ° C.

アン The ammoxidation catalyst obtained by the production method of the present invention exhibits a good acrylonitrile yield in the ammoxidation reaction of propylene.

Hereinafter, a mode for carrying out the present invention (hereinafter, simply referred to as “the present embodiment”) will be described in detail. However, the present invention is not limited to the following embodiment, and does not depart from the gist of the present invention. Various deformations are possible within.

The method for producing a catalyst for ammoxidation of the present embodiment includes a preparation step of preparing a precursor slurry to be a catalyst precursor (step 1), and a drying step of drying the precursor slurry to obtain dry particles (step 2). A firing step (step 3) of firing the dried particles (for example, a denitration step and a main firing step) to obtain an ammoxidation catalyst. The precursor slurry can be obtained, for example, by mixing raw materials of components constituting a catalyst such as a metal component and a carrier. The calorific value calculated from the area value of the exothermic peak having a maximum value in the range of 200 ° C. to 300 ° C. observed by TG-DTA measurement of the dried particles before firing is 45 J / g or more and 200 J / g or less. , Preferably from 80 J / g to 200 J / g, more preferably from 100 J / g to 180 J / g. The calorific value (weight reduction as required) of the dried particles before firing in the TG-DTA measurement can be controlled by, for example, optimizing and combining various preparation conditions in step 1 and drying conditions in step 2. it can.
In particular, in step 1, when aqueous ammonia or water is added to the raw material (preferably, aqueous ammonia or water is added to the molybdenum solution described below), the precipitation of molybdenum in the molybdenum-containing solution can be suppressed, and the calorific value is reduced. It tends to be within the range.

(4) The calorific value and weight loss in the firing step of the dried particles can be measured by a known method. In the present embodiment, the calorific value of the dried particles before calcining is calculated using differential thermal-thermogravimetric simultaneous measurement (TG-DTA), and the calorific value calculated is used as the calorific value in the calcining step of the dried particles. Can be estimated as Differential heat retention measurement is a method of detecting a temperature difference between a reference and a sample using an electromotive force of a thermocouple provided in a measuring device, and measuring a change in calorific value with respect to temperature. Is called the DTA curve. It is known that when an exothermic reaction occurs, a positive peak appears on the DTA curve. Thermogravimetry measures the change in weight of a sample due to an increase in the temperature of the sample with respect to the temperature, and the weight change curve with respect to the temperature change is called a TG curve. As a method for simultaneously measuring the thermogravimetry and the differential heat retention measurement, simultaneous differential thermo-thermogravimetry is known. In this method, since the change in weight of the sample and the endothermic and exothermic reactions during heating can be simultaneously observed, the composition and thermal properties of the substance can be evaluated widely.

In the present embodiment, the calorific value and the weight loss during the firing process of the dried particles are measured using a differential thermo-thermogravimeter (manufactured by Rigaku Co., Ltd., Thermo + plus EVO2 series @ TG8121). It can be estimated by performing a DTA measurement. Specifically, first, the dried particles (20 mg) before firing are placed in a platinum sample container (cylindrical container having an outer diameter of 5.2 mm and a height of 2.5 mm) and subjected to measurement. The measurement conditions are as follows. The temperature range is 10 ° C./min in an air atmosphere, and the temperature range is from room temperature (20 ° C.) to 600 ° C. The weight loss rate of the dry particles is defined as the value obtained by dividing the sample weight at 450 ° C. by the sample weight at the start of measurement. Regarding the calorific value of the dried particles, the measured value (unit: μm · s / g) obtained by the above-described apparatus and conditions was converted to a standard substance (1.Pb melting temperature: 327.5 ° C.) having a known calorific value. (Melting energy: 23.1 J / g, 2. Al melting temperature: 660.3 ° C, melting energy: 399.9 J / g, 3. Sn melting temperature: 231.9 ° C, melting energy: 60.4 J / g). A calculated value (unit: J / g) is obtained by conversion using a calibration curve obtained from the measurement results. Note that, in the differential heat retention measurement, the dried particles before firing in Examples and Comparative Examples described below have a maximum value within a temperature range of 200 ° C. to 300 ° C. when the X-axis is the temperature and the Y-axis is the calorific value. And a positive DTA peak derived from the exothermic reaction.

場合 When the area of the exothermic peak having a maximum value in the range of 200 ° C. to 300 ° C. observed by TG-DTA measurement of the dried particles before firing is 200 J / g or less, the acrylonitrile yield tends to be improved. This is because the frequency of cracking and chipping of the ammoxidation catalyst is reduced by suppressing local heat generation and rapid decomposition of the substance contained in the dried particles and accompanying gas release. it seems to do. Also, when the area value of the exothermic peak is 45 J / g or more, the acrylonitrile yield tends to be improved. The TG-DTA measurement measures the sum of the exothermic reaction and the endothermic reaction, and the high calorific value suggests that the local endothermic reaction rarely occurs simultaneously with the exothermic reaction in the dried particles. are doing. For this reason, it is expected that the crystal precursor constituting the ammoxidation catalyst is heated uniformly and the degree of crystal growth becomes uniform.

場合 When the thermogravimetric loss rate in the range of 20 ° C. to 450 ° C. measured by TG-DTA measurement of the dried particles before firing is 35% or less, the acrylonitrile yield tends to be improved. This indicates that the amount of gas released due to the decomposition reaction of the substance contained in the dried particles is suppressed, and the release of gas is suppressed as the measurement sample is scattered from the sample container during measurement, This is associated with a reduced frequency of cracks and chippings in the ammoxidation catalyst.

The weight change rate and the calorific value in the baking process of the dried particles were used for adjusting the composition (metal composition, raw materials used, the mass ratio of the metal component to the carrier), the type and amount of additives used in preparing the catalyst precursor slurry, and the pH adjustment. It can be controlled by optimizing and combining the amounts of acid and base, drying conditions, and the like. There are no particular restrictions on the slurry preparation step (step 1), the drying conditions (step 2), and the baking step (step 3) as long as the requirements relating to the weight change and the calorific value during the baking step of the dried particles are satisfied. .

The composition of the ammoxidation catalyst used in the present embodiment is not particularly limited, but as an example, a composition containing molybdenum represented by the following general formula (1), bismuth, and iron is preferable. Molybdenum serves as an adsorption site for propylene and an active site for ammonia. Bismuth also plays a role in activating propylene and extracting α-position hydrogen to generate π allyl species. Further, iron plays a role of supplying oxygen present in a gas phase to a catalytically active site by trivalent / divalent redox. By having such a composition, acrylonitrile selectivity tends to be further improved.
_{_{_{_{Mo 12 Bi a Fe b X c}}}} Y d Z e O f (1)
In the formula (1), X is at least one element selected from the group consisting of nickel, cobalt, magnesium, calcium, zinc, strontium and barium, and Y is cerium, chromium, lanthanum, neodymium, yttrium, praseodymium, samarium, aluminum , Gallium, and indium, at least one element selected from the group consisting of potassium, rubidium, and cesium; Z represents at least one element selected from the group consisting of potassium, rubidium, and cesium. a represents the atomic ratio of bismuth to 12 molybdenum atoms, and is 0.1 ≦ a ≦ 2.0, preferably 0.15 ≦ a ≦ 1.0, and more preferably 0.2 ≦ a ≦ 0. 7 b indicates the atomic ratio of iron to 12 molybdenum atoms, and is 0.1 ≦ b ≦ 3.0, preferably 0.5 ≦ b ≦ 2.5, and more preferably 1.0 ≦ b ≦ 2. 0. c indicates the atomic ratio of X to 12 molybdenum atoms, and is 0.1 ≦ c ≦ 10.0, preferably 3.0 ≦ c ≦ 9.0, and more preferably 5.0 ≦ c ≦ 8.0. 5 d indicates the atomic ratio of Y to 12 molybdenum atoms, and is 0.1 ≦ d ≦ 3.0, preferably 0.2 ≦ d ≦ 2.0, and more preferably 0.3 ≦ d ≦ 1. 5 e indicates the atomic ratio of Z to 12 molybdenum atoms, and satisfies 0.01 ≦ e ≦ 2.0, preferably 0.05 ≦ e ≦ 1.0. f indicates the atomic ratio of oxygen to 12 molybdenum atoms, and is the number of oxygen atoms necessary to satisfy the valence requirement of the other elements present.

In the method for producing an ammoxidation catalyst according to the present embodiment, for example, a step of preparing a precursor slurry (precursor slurry) serving as a catalyst precursor by mixing raw materials of components constituting the catalyst such as a metal component and a carrier (Step 1), a step of drying the precursor slurry to obtain dry particles (Step 2), and a step of firing the dry particles (for example, a denitration step and a main firing step) to obtain an ammoxidation catalyst (Step 3). )have.

Step (1) is a step of preparing a precursor slurry by mixing raw materials of components constituting a catalyst such as a metal component and a carrier. Examples of the element source of each metal element include ammonium salts, nitrates, and organic acid salts that are soluble in water or an aqueous acidic solution. These are preferred because they do not cause residual chlorine that occurs when a hydrochloride is used or sulfur that occurs when a sulfate is used.

(4) The raw material of the carrier is not particularly limited as long as it is commonly used, and examples thereof include oxides such as silica, alumina, titania, and zirconia. Of these, silica is preferable. Silica is itself inert compared to other oxides and has a good binding effect on active catalyst components.

(4) The order of mixing the components when preparing the precursor slurry is not particularly limited. For example, the following is an example of the embodiment of the composition represented by the general formula (1). First, an ammonium salt of molybdenum (hereinafter, referred to as a molybdenum solution) dissolved in warm water is added to a silica sol (hereinafter, referred to as a silica solution). Next, a solution obtained by dissolving a nitrate as an element source of each element such as bismuth, cerium, iron, chromium, nickel, magnesium, zinc, manganese, cobalt, rubidium, cesium, and potassium in an aqueous nitric acid solution (hereinafter, referred to as an aqueous metal nitrate solution) ) To obtain a precursor slurry. Further, the precursor slurry does not necessarily need to contain all the elements constituting the catalyst, and the raw materials of the elements not contained in the precursor slurry may be added in each step before the firing step. Or by impregnating the dried catalyst.

The pH of the slurry can be changed by adjusting the concentration of nitric acid used or adding various additives to the silica sol, molybdenum solution, or metal nitrate aqueous solution in the above-described method for preparing the raw material slurry. In the present embodiment, for example, ammonia water or water is added to the molybdenum solution from the viewpoint of suppressing the precipitation of molybdenum oxide. In the present embodiment, the addition of ammonia water or water can change the form of the metal in the slurry or increase the amount of ammonium nitrate in the slurry. The amount of heat generated in the firing step of the dried particles tends to increase with the addition of, and the amount of heat generated can be within the above range.
The concentration of the aqueous ammonia may be, for example, about 5 to 30% by mass.
The addition amount of ammonia water or water may be, for example, about 1 to 10 parts by mass with respect to 100 parts by mass of the molybdenum solution.

As for the additives to be added at the time of preparing the precursor slurry, water-soluble polymers such as polyethylene glycol, methylcellulose, polyvinyl alcohol, polyacrylic acid, and polyacrylamide, amines, carboxylic acids, aminocarboxylic acids, and other organic acids are appropriately added to silica sol or A precursor slurry can be prepared by adding to a molybdenum solution or an aqueous metal nitrate solution. Among these additives, oxalic acid, iminodiacetic acid, and pyridine are more preferable.

Since the amount of heat generated (endothermic) during decomposition and combustion of additives differs depending on the type, the relationship between the increase / decrease of the amount of addition and the amount of heat generated (endothermic) cannot be defined uniquely, but by adjusting the amount of addition It is preferable to adjust the calorific value of the dried particles from the viewpoint of improving the yield of acrylonitrile. Generally, the content of the additive is preferably 0.01 to 0.10 molar equivalents relative to the total amount of the metal elements constituting the ammoxidation catalyst in the precursor slurry. More preferably, it is 0.02 to 0.07 molar equivalent. When the content of the additive is 0.01 molar equivalent or more, there is an effect on the calorific value, and the effect of the additive is exhibited. Further, when the content of the additive is 0.10 molar equivalent or less, the weight loss due to the decomposition and burning of the additive is suppressed, and the weight change rate of the dried particles is suppressed.

質量 The mass ratio of metal oxide to carrier in the ammoxidation catalyst is preferably metal oxide: carrier = 55: 45 to 65:35. When the content of the carrier is increased, the calorific value derived from the metal raw material decreases. Further, the content of the carrier is preferably 35% by mass or more from the viewpoint of strength such as crush resistance and wear resistance under practical conditions.

Step 2 is a step of drying the precursor slurry to obtain dried particles. Preferably, it is a step of spray-drying the precursor slurry to obtain dry particles. By spray drying the precursor slurry, spherical fine particles suitable for a fluidized bed reaction can be obtained. As the spray drying device, a general device such as a rotating disk type or a nozzle type can be used. By adjusting the spray-drying conditions, it becomes possible to control the calorific value and weight loss during the calcination of the dried particles and to adjust the particle size of the catalyst. When the resulting ammoxidation catalyst is used as a fluidized bed catalyst, the particle size of the ammoxidation catalyst is preferably 25 to 180 μm. An example of preferable spray drying conditions is as follows. Using a centrifugal atomizer equipped with a dish-shaped rotor installed at the center of the upper part of the dryer, the inlet air temperature of the dryer is 180 to 280 ° C., and the outlet temperature is Conditions for maintaining the temperature at 100 to 170 ° C. are mentioned.

Step 3 is a step of calcining the dried particles obtained by drying to obtain an ammoxidation catalyst. Since the dried particles can contain nitric acid, it is preferable to perform a denitration treatment before the main baking. In the denitration treatment, heating is preferably performed at 150 to 450 ° C. for 1.5 to 3 hours. The firing temperature is preferably 550 to 650 ° C. When the firing temperature is 570 ° C. or higher, crystal growth proceeds sufficiently, and the acrylonitrile selectivity of the resulting ammoxidation catalyst tends to be further improved. Further, when the calcination temperature is 650 ° C. or lower, the surface area of the obtained catalyst for ammoxidation is increased, and the reaction activity of propylene tends to be further improved. The gas atmosphere used for denitration and firing may be an oxidizing gas atmosphere containing oxygen or an inert gas atmosphere such as nitrogen, for example, but it is convenient to use air.

The method for producing acrylonitrile of the present embodiment is a reaction step of producing acrylonitrile by reacting propylene, molecular oxygen, and ammonia (ammoxidation reaction) in the presence of the ammoxidation catalyst obtained by the above-described method. Having. The production of acrylonitrile by an ammoxidation reaction can be carried out in a fixed-bed reactor or a fluidized-bed reactor (fluidized reactor). Among these, a fluidized bed reactor (fluidized reaction tank) is preferable from the viewpoint of efficiently removing heat generated during the reaction and increasing the yield of acrylonitrile. When the reaction step is performed in a fluidized reaction tank, it is preferable that an ammoxidation catalyst is supplied to the fluidized reaction tank in advance, and the ammoxidation reaction is performed while the catalyst is circulated in the fluidized reaction tank. The raw materials for the ammoxidation reaction, propylene and ammonia, do not necessarily need to be of high purity, and industrial grade ones can be used. When the molecular oxygen source is air, the molar ratio of propylene, ammonia and air in the raw material gas (propylene / ammonia / air) is preferably 1 / (0.8 to 1.4) / (7 to 12). The reaction temperature is more preferably in the range of 1 / (0.9 to 1.3) / (8 to 11), preferably 350 to 550 ° C, more preferably 400 to 500 ° C. Range. The reaction pressure is preferably from normal pressure to 0.3 MPa. The contact time between the raw material gas and the ammoxidation catalyst is preferably 3 to 6 seconds.

The reaction tube used for the propylene ammoxidation reaction is not particularly limited, and for example, a Pyrex (registered trademark) glass tube having an internal diameter of 25 mm and 16 10-mesh wire nets incorporated at 1 cm intervals can be used. Specific examples of the ammoxidation reaction are not particularly limited. For example, first, the amount of the ammoxidation catalyst is set to 50 cc, the reaction temperature is set to 430 ° C., the reaction pressure is set to 0.17 MPa, and the mixed gas (propylene, ammonia , Oxygen and helium). The volume ratio of ammonia to propylene is set so that the specific sulfuric acid unit defined by the following equation is 20 kg / T-AN. The molar ratio of ammonia / propylene at this time is defined as N / C. The volume ratio of oxygen to propylene is set such that the oxygen concentration of the gas at the outlet of the reactor is 0.2 ± 0.02% by volume. The molar amount of oxygen at that time is converted to the molar amount of air on the assumption that the air contains 21% of oxygen. The molar ratio of air / propylene at this time is defined as A / C. Also, by changing the flow rate of the mixed gas, the contact time defined by the following equation can be changed. Thus, the propylene conversion defined by the following equation can be set to 99.3 ± 0.2%. Sulfuric acid unit, contact time, propylene conversion, and acrylonitrile yield are defined as follows.

本 The present embodiment will be described in more detail with reference to examples below, but the present embodiment is not limited to the examples described below. The catalyst compositions described in Examples and Comparative Examples have the same values as the charged compositions of the respective elements.

[TG-DTA measurement]
The calorific value and weight loss during the firing process of the dried particles are determined by TG-DTA measurement of the dried particles before firing using a differential thermo-thermogravimeter (Thermo plus EVO2 series TG8121 manufactured by Rigaku Corporation). Estimated by Specifically, first, the dried particles (20 mg) before firing were placed in a platinum sample container (cylindrical container having an outer diameter of 5.2 mm and a height of 2.5 mm) and subjected to measurement. The measurement conditions were as follows: the temperature was raised at a rate of 10 ° C./min in an air atmosphere; The weight loss rate of the dry particles was defined as the value obtained by dividing the sample weight at 450 ° C. by the sample weight at the start of measurement. Regarding the calorific value of the dried particles, the measured value (unit: μm · s / g) obtained by the above-described apparatus and conditions was converted into a standard substance (1. Pb melting temperature: 327.5 ° C. (Melting energy: 23.1 J / g, 2. Al melting temperature: 660.3 ° C, melting energy: 399.9 J / g, 3. Sn melting temperature: 231.9 ° C, melting energy: 60.4 J / g). The calculated value (unit: J / g) was obtained by conversion using a calibration curve obtained from the measurement results. Note that, in each of the dried particles before firing in the present example and the comparative example, when the X-axis is temperature and the Y-axis is the calorific value in the differential heat retention measurement, the maximum value is in a temperature range of 200 ° C to 300 ° C. It had a positive DTA peak from the exothermic reaction shown.

[Sulfuric acid unit, contact time, propylene conversion, acrylonitrile yield]
As a reaction tube used for the propylene ammoxidation reaction, a Pyrex (registered trademark) glass tube having an inner diameter of 25 mm and containing 16 10-mesh metal meshes at 1 cm intervals was used. In the ammoxidation reaction, the amount of the ammoxidation catalyst was set at 50 cc, the reaction temperature was set at 430 ° C., the reaction pressure was set at 0.17 MPa, and a mixed gas (propylene, ammonia, oxygen, helium) having a propylene volume of 9% was passed. The volume ratio of ammonia to propylene was set so that the specific sulfuric acid unit defined by the following formula was 20 kg / T-AN. The molar ratio of ammonia / propylene at this time was defined as N / C. The volume ratio of oxygen to propylene was set so that the oxygen concentration of the gas at the outlet of the reactor was 0.2 ± 0.02% by volume. The molar amount of oxygen at that time was converted to the molar amount of air, assuming that the air contained 21% of oxygen. The molar ratio of air / propylene at this time was defined as A / C. The contact time defined by the following equation was changed by changing the flow rate of the mixed gas. Thereby, the propylene conversion defined by the following equation was set to 99.3 ± 0.2%. Sulfuric acid unit, contact time, propylene conversion, and acrylonitrile yield were defined as in the following formula.

[Example 1]
Catalyst (metal oxide) in which a metal oxide whose composition is represented by Mo _12.00 Bi _0.47 Ce _0.99 Fe _1.88 Ni _3.08 Co _3.90 Rb _0.15 is supported on silica. : 60% by mass, silica: 40% by mass) according to the following procedure.
First, 1333 g of silica sol containing 30% by mass of SiO ₂ was put in a container with a lid, kept at 40 ° C., and stirred at a rotation speed of 120 rpm while oxalic acid dihydrate 25 dissolved in 287.5 g of water. 0.0 g (equivalent to 2.5% by mass of the finally obtained catalyst powder) was added, and the mixture was capped and stirred for 10 minutes to obtain an aqueous silica solution. Put ammonium paramolybdate in 476.7g to another lidded container _{_{_{_{[(NH 4) 6 Mo 7}}}} O 24 · 4H 2 O], was dissolved in warm water at 60 ° C. of 850.8G. After cooling to 45 ° C., 35.8 g of a 15% by mass aqueous ammonia solution was added to obtain a molybdenum aqueous solution. Furthermore, 51.6 g of bismuth nitrate into another lidded container _{_{_{[Bi (NO 3) 3 ·}}} 5H 2 O], cerium nitrate _{_{_{96.1g [Ce (NO 3) 3}}} · 6H 2 O], of 171.2g iron nitrate _{_{_{[Fe (NO 3) 3 ·}}} 9H 2 O], 203.4g of nickel nitrate _{_{_{[Ni (NO 3) 2 ·}}} 6H 2 O], cobalt nitrate _{_{258.8g [Co (NO 3) 2}} · 6H 2 O] and 5.0 g of rubidium nitrate [RbNO ₃ ] were dissolved in 13.3% by mass of nitric acid (393.3 g) and kept at 40 ° C. to obtain a nitrate aqueous solution. The aqueous molybdenum solution was added to the aqueous silica solution while maintaining the temperature at 40 ° C. and stirring at a stirring rotation speed of 200 rpm to obtain an aqueous silica / molybdenum solution. After stirring for 5 minutes, the mixture was kept at 40 ° C. and the nitrate aqueous solution was added to the silica / molybdenum aqueous solution while stirring at a stirring rotation speed of 250 rpm to prepare a raw material slurry. A precursor slurry was prepared by stirring the raw slurry at 40 ° C for 45 minutes. The obtained precursor slurry was dried using a rotating disk type spray dryer to obtain dried particles. At this time, the air temperature at the dryer inlet was 230 ° C, and the air temperature at the outlet was 110 ° C. The rotation speed of the disk was set at 12,500 rpm. When TG-DTA measurement was performed using the obtained dried particles, the calorific value calculated from the area of the exothermic peak having a maximum value in the range of 200 ° C. to 300 ° C. was 104 J / g, and the weight loss was 31. 5%. The dried particles were held at 200 ° C. for 5 minutes, heated from 200 ° C. to 450 ° C. at a rate of 2.5 ° C./minute, and denitrated by holding at 450 ° C. for 20 minutes. The denitrated dry particles were calcined at 595 ° C. for 2 hours to obtain an ammoxidation catalyst. The obtained ammoxidation catalyst is supplied in advance to a fluidized reaction vessel, and propylene, molecular oxygen, and ammonia are reacted (ammoxidation reaction) while circulating the catalyst in the fluidized reaction vessel, Acrylonitrile was produced and the molar ratio of ammonia / propylene (N / C), the molar ratio of air / propylene (A / C), and the acrylonitrile yield were determined. Table 1 shows the results.

[Example 2]
Catalyst (metal oxide) in which a metal oxide whose composition is represented by Mo _12.00 Bi _0.47 Ce _0.99 Fe _1.88 Ni _3.08 Co _3.90 Rb _0.15 is supported on silica. : 60% by mass, silica: 40% by mass) according to the following procedure.
First, 1333 g of silica sol containing 30% by mass of SiO ₂ was placed in a container with a lid, kept at 40 ° C., and stirred at a stirring rotation speed of 120 rpm to obtain a silica aqueous solution. Put ammonium paramolybdate in 476.7g to another lidded container _{_{_{_{[(NH 4) 6 Mo 7}}}} O 24 · 4H 2 O], was dissolved in warm water at 60 ° C. of 850.8G. After cooling to 45 ° C., 35.8 g of a 15% by mass aqueous ammonia solution was added to obtain a molybdenum aqueous solution. Furthermore, 51.6 g of bismuth nitrate into another lidded container _{_{_{[Bi (NO 3) 3 ·}}} 5H 2 O], cerium nitrate _{_{_{96.1g [Ce (NO 3) 3}}} · 6H 2 O], of 171.2g iron nitrate _{_{_{[Fe (NO 3) 3 ·}}} 9H 2 O], 203.4g of nickel nitrate _{_{_{[Ni (NO 3) 2 ·}}} 6H 2 O], cobalt nitrate _{_{258.8g [Co (NO 3) 2}} · 6H 2 O] and 5.0 g of rubidium nitrate [RbNO ₃ ] were dissolved in 13.3% by mass of nitric acid (393.3 g) and kept at 40 ° C. to obtain a nitrate aqueous solution. The aqueous molybdenum solution was added to the aqueous silica solution while maintaining the temperature at 40 ° C. and stirring at a stirring rotation speed of 200 rpm to obtain an aqueous silica / molybdenum solution. After stirring for 5 minutes, the mixture was kept at 40 ° C. and the nitrate aqueous solution was added to the silica / molybdenum aqueous solution while stirring at a stirring rotation speed of 250 rpm to prepare a raw material slurry. A precursor slurry was prepared by stirring the raw slurry at 40 ° C for 45 minutes. The obtained precursor slurry was dried using a rotating disk type spray dryer to obtain dried particles. At this time, the air temperature at the dryer inlet was 230 ° C, and the air temperature at the outlet was 110 ° C. The rotation speed of the disk was set at 12,500 rpm. When TG-DTA measurement was performed using the obtained dried particles, the calorific value calculated from the area of the exothermic peak having a maximum value in the range of 200 ° C. to 300 ° C. was 98 J / g, and the weight loss was 27. 2%. The dried particles were held at 200 ° C. for 5 minutes, heated from 200 ° C. to 450 ° C. at a rate of 2.5 ° C./minute, and denitrated by holding at 450 ° C. for 20 minutes. The denitrated dry particles were calcined at 595 ° C. for 2 hours to obtain an ammoxidation catalyst. The obtained ammoxidation catalyst is supplied in advance to a fluidized reaction vessel, and propylene, molecular oxygen, and ammonia are reacted (ammoxidation reaction) while circulating the catalyst in the fluidized reaction vessel, Acrylonitrile was produced and the molar ratio of ammonia / propylene (N / C), the molar ratio of air / propylene (A / C), and the acrylonitrile yield were determined. Table 1 shows the results.

[Example 3]
Catalyst (metal oxide) in which a metal oxide whose composition is represented by Mo _12.00 Bi _0.47 Ce _0.99 Fe _1.88 Ni _3.08 Co _3.90 Rb _0.15 is supported on silica. : 60% by mass, silica: 40% by mass) according to the following procedure.
First, 1333 g of silica sol containing 30% by mass of SiO ₂ was put in a container with a lid, kept at 40 ° C., and stirred at a rotation speed of 120 rpm while oxalic acid dihydrate 25 dissolved in 287.5 g of water. 0.0 g (equivalent to 2.5% by mass of the finally obtained catalyst powder) was added, and the mixture was capped and stirred for 10 minutes to obtain an aqueous silica solution. Put ammonium paramolybdate in 476.7g to another lidded container _{_{_{_{[(NH 4) 6 Mo 7}}}} O 24 · 4H 2 O], was dissolved in warm water at 60 ° C. of 850.8G. After cooling to 45 ° C., 53.7 g of water was added to obtain a molybdenum aqueous solution. Furthermore, 51.6 g of bismuth nitrate into another lidded container _{_{_{[Bi (NO 3) 3 ·}}} 5H 2 O], cerium nitrate _{_{_{96.1g [Ce (NO 3) 3}}} · 6H 2 O], of 171.2g iron nitrate _{_{_{[Fe (NO 3) 3 ·}}} 9H 2 O], 203.4g of nickel nitrate _{_{_{[Ni (NO 3) 2 ·}}} 6H 2 O], cobalt nitrate _{_{258.8g [Co (NO 3) 2}} · 6H 2 O] and 5.0 g of rubidium nitrate [RbNO ₃ ] were dissolved in 13.3% by mass of nitric acid (393.3 g) and kept at 40 ° C. to obtain a nitrate aqueous solution. The aqueous molybdenum solution was added to the aqueous silica solution while maintaining the temperature at 40 ° C. and stirring at a stirring rotation speed of 200 rpm to obtain an aqueous silica / molybdenum solution. After stirring for 5 minutes, the mixture was kept at 40 ° C. and the nitrate aqueous solution was added to the silica / molybdenum aqueous solution while stirring at a stirring rotation speed of 250 rpm to prepare a raw material slurry. A precursor slurry was prepared by stirring the raw slurry at 40 ° C for 45 minutes. The obtained precursor slurry was dried using a rotating disk type spray dryer to obtain dried particles. At this time, the air temperature at the dryer inlet was 235 ° C, and the air temperature at the outlet was 110 ° C. The rotation speed of the disk was set at 12,500 rpm. When TG-DTA measurement was performed using the obtained dried particles, the calorific value calculated from the area of the exothermic peak having a maximum value in the range of 200 ° C. to 300 ° C. was 101 J / g, and the weight loss was 30. 5%. The dried particles were held at 200 ° C. for 5 minutes, heated from 200 ° C. to 450 ° C. at a rate of 2.5 ° C./minute, and denitrated by holding at 450 ° C. for 20 minutes. The denitrated dry particles were calcined at 595 ° C. for 2 hours to obtain an ammoxidation catalyst. The obtained ammoxidation catalyst is supplied in advance to a fluidized reaction vessel, and propylene, molecular oxygen, and ammonia are reacted (ammoxidation reaction) while circulating the catalyst in the fluidized reaction vessel, Acrylonitrile was produced and the molar ratio of ammonia / propylene (N / C), the molar ratio of air / propylene (A / C), and the acrylonitrile yield were determined. Table 1 shows the results.

[Example 4]
Catalyst (metal oxide) in which a metal oxide whose composition is represented by Mo _12.00 Bi _0.47 Ce _0.99 Fe _1.88 Ni _3.08 Co _3.90 Rb _0.15 is supported on silica. : 60% by mass, silica: 40% by mass) according to the following procedure.
First, 1333 g of silica sol containing 30% by mass of SiO ₂ was placed in a container with a lid, kept at 40 ° C., and stirred at a stirring rotation speed of 120 rpm to obtain a silica aqueous solution. Put ammonium paramolybdate in 476.7g to another lidded container _{_{_{_{[(NH 4) 6 Mo 7}}}} O 24 · 4H 2 O], was dissolved in warm water at 60 ° C. of 850.8G. After cooling to 45 ° C., 53.7 g of water was added to obtain a molybdenum aqueous solution. Furthermore, 51.6 g of bismuth nitrate into another lidded container _{_{_{[Bi (NO 3) 3 ·}}} 5H 2 O], cerium nitrate _{_{_{96.1g [Ce (NO 3) 3}}} · 6H 2 O], of 171.2g iron nitrate _{_{_{[Fe (NO 3) 3 ·}}} 9H 2 O], 203.4g of nickel nitrate _{_{_{[Ni (NO 3) 2 ·}}} 6H 2 O], cobalt nitrate _{_{258.8g [Co (NO 3) 2}} · 6H 2 O] and 5.0 g of rubidium nitrate [RbNO ₃ ] were dissolved in 13.3% by mass of nitric acid (393.3 g) and kept at 40 ° C. to obtain a nitrate aqueous solution. The aqueous molybdenum solution was added to the aqueous silica solution while maintaining the temperature at 40 ° C. and stirring at a stirring rotation speed of 200 rpm to obtain an aqueous silica / molybdenum solution. After stirring for 5 minutes, the mixture was kept at 40 ° C. and the nitrate aqueous solution was added to the silica / molybdenum aqueous solution while stirring at a stirring rotation speed of 250 rpm to prepare a raw material slurry. A precursor slurry was prepared by stirring the raw slurry at 40 ° C for 45 minutes. The obtained precursor slurry was dried using a rotating disk type spray dryer to obtain dried particles. At this time, the air temperature at the dryer inlet was 235 ° C, and the air temperature at the outlet was 110 ° C. The rotation speed of the disk was set at 12,500 rpm. When TG-DTA measurement was performed using the obtained dried particles, the calorific value calculated from the area of the exothermic peak having a maximum value in the range of 200 ° C. to 300 ° C. was 95 J / g, and the weight loss was 26. 1%. The dried particles were held at 200 ° C. for 5 minutes, heated from 200 ° C. to 450 ° C. at a rate of 2.5 ° C./minute, and denitrated by holding at 450 ° C. for 20 minutes. The denitrated dry particles were calcined at 595 ° C. for 2 hours to obtain an ammoxidation catalyst. The obtained ammoxidation catalyst is supplied in advance to a fluidized reaction vessel, and propylene, molecular oxygen, and ammonia are reacted (ammoxidation reaction) while circulating the catalyst in the fluidized reaction vessel, Acrylonitrile was produced and the molar ratio of ammonia / propylene (N / C), the molar ratio of air / propylene (A / C), and the acrylonitrile yield were determined. Table 1 shows the results.

[Example 5]
Catalyst (metal oxide) in which a metal oxide whose composition is represented by Mo _12.00 Bi _0.47 Ce _0.99 Fe _1.88 Ni _3.08 Co _3.90 Rb _0.15 is supported on silica. : 60% by mass, silica: 40% by mass) according to the following procedure.
First, 1333 g of silica sol containing 30% by mass of SiO ₂ was placed in a container with a lid, kept at 40 ° C., and stirred at a stirring rotation speed of 120 rpm to obtain a silica aqueous solution. Put ammonium paramolybdate in 476.7g to another lidded container _{_{_{_{[(NH 4) 6 Mo 7}}}} O 24 · 4H 2 O], was dissolved in warm water at 60 ° C. of 850.8G. After cooling to 55 ° C., 26.9 g of water was added and kept at 55 ° C. to obtain an aqueous molybdenum solution. Furthermore, 51.6 g of bismuth nitrate into another lidded container _{_{_{[Bi (NO 3) 3 ·}}} 5H 2 O], cerium nitrate _{_{_{96.1g [Ce (NO 3) 3}}} · 6H 2 O], of 171.2g iron nitrate _{_{_{[Fe (NO 3) 3 ·}}} 9H 2 O], 203.4g of nickel nitrate _{_{_{[Ni (NO 3) 2 ·}}} 6H 2 O], cobalt nitrate _{_{258.8g [Co (NO 3) 2}} · 6H 2 O] and 5.0 g of rubidium nitrate [RbNO ₃ ] were dissolved in 13.3% by mass of nitric acid (393.3 g) and kept at 40 ° C. to obtain a nitrate aqueous solution. The aqueous molybdenum solution was added to the aqueous silica solution while maintaining the temperature at 40 ° C. and stirring at a stirring rotation speed of 200 rpm to obtain an aqueous silica / molybdenum solution. After stirring for 5 minutes, the mixture was kept at 40 ° C. and the nitrate aqueous solution was added to the silica / molybdenum aqueous solution while stirring at a stirring rotation speed of 250 rpm to prepare a raw material slurry. A precursor slurry was prepared by stirring the raw slurry at 40 ° C for 45 minutes. The obtained precursor slurry was dried using a rotating disk type spray dryer to obtain dried particles. At this time, the air temperature at the dryer inlet was 230 ° C, and the air temperature at the outlet was 110 ° C. The rotation speed of the disk was set at 12,500 rpm. When TG-DTA measurement was performed using the obtained dried particles, the calorific value calculated from the area of the exothermic peak having a maximum value in the range of 200 ° C. to 300 ° C. was 52 J / g, and the weight loss was 26. 3%. The dried particles were held at 200 ° C. for 5 minutes, heated from 200 ° C. to 450 ° C. at a rate of 2.5 ° C./minute, and denitrated by holding at 450 ° C. for 20 minutes. The denitrated dry particles were calcined at 595 ° C. for 2 hours to obtain an ammoxidation catalyst. The obtained ammoxidation catalyst is supplied in advance to a fluidized reaction vessel, and propylene, molecular oxygen, and ammonia are reacted (ammoxidation reaction) while circulating the catalyst in the fluidized reaction vessel, Acrylonitrile was produced and the molar ratio of ammonia / propylene (N / C), the molar ratio of air / propylene (A / C), and the acrylonitrile yield were determined. Table 1 shows the results.

[Example 6]
Catalyst (metal oxide) in which a metal oxide whose composition is represented by Mo _12.00 Bi _0.47 Ce _0.99 Fe _1.88 Ni _3.08 Co _3.90 Rb _0.15 is supported on silica. : 60% by mass, silica: 40% by mass) according to the following procedure.
First, 1333 g of silica sol containing 30% by mass of SiO ₂ was put in a container with a lid, kept at 40 ° C., and stirred at a rotation speed of 120 rpm while oxalic acid dihydrate 25 dissolved in 287.5 g of water. 0.0 g (equivalent to 2.5% by mass of the finally obtained catalyst powder) was added, and the mixture was capped and stirred for 10 minutes to obtain an aqueous silica solution. Put ammonium paramolybdate in 476.7g to another lidded container _{_{_{_{[(NH 4) 6 Mo 7}}}} O 24 · 4H 2 O], was dissolved in warm water at 60 ° C. of 850.8G. After cooling to 45 ° C., 35.8 g of a 15% by mass aqueous ammonia solution was added to obtain a molybdenum aqueous solution. Furthermore, 51.6 g of bismuth nitrate into another lidded container _{_{_{[Bi (NO 3) 3 ·}}} 5H 2 O], cerium nitrate _{_{_{96.1g [Ce (NO 3) 3}}} · 6H 2 O], of 171.2g iron nitrate _{_{_{[Fe (NO 3) 3 ·}}} 9H 2 O], 203.4g of nickel nitrate _{_{_{[Ni (NO 3) 2 ·}}} 6H 2 O], cobalt nitrate _{_{258.8g [Co (NO 3) 2}} · 6H 2 O] and 5.0 g of rubidium nitrate [RbNO ₃ ] were dissolved in 13.3% by mass of nitric acid (393.3 g) and kept at 40 ° C. to obtain a nitrate aqueous solution. The aqueous molybdenum solution was added to the aqueous silica solution while maintaining the temperature at 40 ° C. and stirring at a stirring rotation speed of 200 rpm to obtain an aqueous silica / molybdenum solution. After stirring for 5 minutes, the mixture was kept at 40 ° C. and the nitrate aqueous solution was added to the silica / molybdenum aqueous solution while stirring at a stirring rotation speed of 250 rpm to prepare a raw material slurry. A precursor slurry was prepared by stirring the raw slurry at 40 ° C for 45 minutes. The obtained precursor slurry was dried using a rotating disk type spray dryer to obtain dried particles. At this time, the air temperature at the dryer inlet was 270 ° C, and the air temperature at the outlet was 155 ° C. The rotation speed of the disk was set at 12,500 rpm. When TG-DTA measurement was performed using the obtained dried particles, the calorific value calculated from the area of the exothermic peak having a maximum value in the range of 200 ° C. to 300 ° C. was 94 J / g, and the weight loss was 26. 9%. The dried particles were held at 200 ° C. for 5 minutes, heated from 200 ° C. to 450 ° C. at a rate of 2.5 ° C./minute, and denitrated by holding at 450 ° C. for 20 minutes. The denitrated dry particles were calcined at 595 ° C. for 2 hours to obtain an ammoxidation catalyst. The obtained ammoxidation catalyst is supplied in advance to a fluidized reaction vessel, and propylene, molecular oxygen, and ammonia are reacted (ammoxidation reaction) while circulating the catalyst in the fluidized reaction vessel, Acrylonitrile was produced and the molar ratio of ammonia / propylene (N / C), the molar ratio of air / propylene (A / C), and the acrylonitrile yield were determined. Table 1 shows the results.

[Example 7] A metal oxide represented by Mo _12.00 Bi _0.47 Ce _0.99 Fe _1.88 Ni _3.08 Co _3.90 Rb _0.15 was supported on silica. A catalyst (metal oxide: 60% by mass, silica: 40% by mass) was produced by the following procedure.
First, 1333 g of silica sol containing 30% by mass of SiO ₂ was placed in a container with a lid, and 25.0 g of oxalic acid dissolved in 287.5 g of water was added while stirring at 40 ° C. and stirring at a rotation speed of 120 rpm. Then, after covering, the mixture was stirred for 10 minutes to obtain an aqueous silica solution. Put ammonium paramolybdate in 476.7g to another lidded container _{_{_{_{[(NH 4) 6 Mo 7}}}} O 24 · 4H 2 O], was dissolved in warm water at 60 ° C. of 850.8G. After cooling to 45 ° C., 35.8 g of a 15% by mass aqueous ammonia solution was added to obtain a molybdenum aqueous solution. Furthermore, 51.6 g of bismuth nitrate into another lidded container _{_{_{[Bi (NO 3) 3 ·}}} 5H 2 O], cerium nitrate _{_{_{96.1g [Ce (NO 3) 3}}} · 6H 2 O], of 171.2g iron nitrate _{_{_{[Fe (NO 3) 3 ·}}} 9H 2 O], 203.4g of nickel nitrate _{_{_{[Ni (NO 3) 2 ·}}} 6H 2 O], cobalt nitrate _{_{258.8g [Co (NO 3) 2}} · 6H 2 O] and 5.0 g of rubidium nitrate [RbNO ₃ ] were dissolved in 13.3% by mass of nitric acid (393.3 g) and kept at 40 ° C. to obtain a nitrate aqueous solution. The aqueous molybdenum solution was added to the aqueous silica solution while maintaining the temperature at 40 ° C. and stirring at a stirring rotation speed of 200 rpm to obtain an aqueous silica / molybdenum solution. After stirring for 5 minutes, the mixture was kept at 40 ° C. and the nitrate aqueous solution was added to the silica / molybdenum aqueous solution while stirring at a stirring rotation speed of 250 rpm to prepare a raw material slurry. The raw material slurry was stirred at 40 ° C. for 45 minutes with a lid, and 20.0 g of a 28% by mass aqueous ammonia solution was added to prepare a precursor slurry. The obtained precursor slurry was dried using a rotating disk type spray dryer to obtain dried particles. At this time, the air temperature at the dryer inlet was 270 ° C, and the air temperature at the outlet was 155 ° C. The rotation speed of the disk was set at 12,500 rpm. When TG-DTA measurement was performed using the obtained dried particles, the calorific value calculated from the area of the exothermic peak having a maximum value in the range of 200 ° C. to 300 ° C. was 114 J / g, and the weight loss was 27. 4%. The dried particles were held at 200 ° C. for 5 minutes, heated from 200 ° C. to 450 ° C. at a rate of 2.5 ° C./minute, and denitrated by holding at 450 ° C. for 20 minutes. The denitrated dry particles were calcined at 595 ° C. for 2 hours to obtain an ammoxidation catalyst. The obtained ammoxidation catalyst is supplied in advance to a fluidized reaction vessel, and propylene, molecular oxygen, and ammonia are reacted (ammoxidation reaction) while circulating the catalyst in the fluidized reaction vessel, Acrylonitrile was produced and the molar ratio of ammonia / propylene (N / C), the molar ratio of air / propylene (A / C), and the acrylonitrile yield were determined. Table 1 shows the results.

Example 8
Catalyst (metal oxide) in which a metal oxide whose composition is represented by Mo _12.00 Bi _0.47 Ce _0.99 Fe _1.88 Ni _3.08 Co _3.90 Rb _0.15 is supported on silica. : 60% by mass, silica: 40% by mass) according to the following procedure.
First, 1333 g of silica sol containing 30% by mass of SiO ₂ was placed in a container with a lid, kept at 40 ° C., and 25.0 g of iminodiacetic acid dissolved in 287.5 g of water while stirring at a stirring rotation speed of 120 rpm ( (Equivalent to 2.5% by mass of the finally obtained catalyst powder) was added, and the mixture was capped and stirred for 10 minutes to obtain an aqueous silica solution. Put ammonium paramolybdate in 476.7g to another lidded container _{_{_{_{[(NH 4) 6 Mo 7}}}} O 24 · 4H 2 O], was dissolved in warm water at 60 ° C. of 850.8G. After cooling to 45 ° C., 35.8 g of a 15% by mass aqueous ammonia solution was added to obtain a molybdenum aqueous solution. Furthermore, 51.6 g of bismuth nitrate into another lidded container _{_{_{[Bi (NO 3) 3 ·}}} 5H 2 O], cerium nitrate _{_{_{96.1g [Ce (NO 3) 3}}} · 6H 2 O], of 171.2g iron nitrate _{_{_{[Fe (NO 3) 3 ·}}} 9H 2 O], 203.4g of nickel nitrate _{_{_{[Ni (NO 3) 2 ·}}} 6H 2 O], cobalt nitrate _{_{258.8g [Co (NO 3) 2}} · 6H 2 O] and 5.0 g of rubidium nitrate [RbNO ₃ ] were dissolved in 13.3% by mass of nitric acid (393.3 g) and kept at 40 ° C. to obtain a nitrate aqueous solution. The aqueous molybdenum solution was added to the aqueous silica solution while maintaining the temperature at 40 ° C. and stirring at a stirring rotation speed of 200 rpm to obtain an aqueous silica / molybdenum solution. After stirring for 5 minutes, the mixture was kept at 40 ° C. and the nitrate aqueous solution was added to the silica / molybdenum aqueous solution while stirring at a stirring rotation speed of 250 rpm to prepare a raw material slurry. A precursor slurry was prepared by stirring the raw slurry at 40 ° C for 45 minutes. The obtained precursor slurry was dried using a rotating disk type spray dryer to obtain dried particles. At this time, the air temperature at the dryer inlet was 270 ° C, and the air temperature at the outlet was 155 ° C. The rotation speed of the disk was set at 12,500 rpm. When TG-DTA measurement was performed using the obtained dried particles, the calorific value calculated from the area of the exothermic peak having a maximum value in the range of 200 ° C. to 300 ° C. was 81 J / g, and the weight loss rate was 27. 0.5%. The dried particles were held at 200 ° C. for 5 minutes, heated from 200 ° C. to 450 ° C. at a rate of 2.5 ° C./minute, and denitrated by holding at 450 ° C. for 20 minutes. The denitrated dry particles were calcined at 595 ° C. for 2 hours to obtain an ammoxidation catalyst. The obtained ammoxidation catalyst is supplied in advance to a fluidized reaction vessel, and propylene, molecular oxygen, and ammonia are reacted (ammoxidation reaction) while circulating the catalyst in the fluidized reaction vessel, Acrylonitrile was produced and the molar ratio of ammonia / propylene (N / C), the molar ratio of air / propylene (A / C), and the acrylonitrile yield were determined. Table 1 shows the results.

[Example 9]
Catalyst (metal oxide) in which a metal oxide whose composition is represented by Mo _12.00 Bi _0.47 Ce _0.99 Fe _1.88 Ni _3.08 Co _3.90 Rb _0.15 is supported on silica. : 60% by mass, silica: 40% by mass) according to the following procedure.
First, 1333 g of silica sol containing 30% by mass of SiO ₂ was placed in a container with a lid, and 25.0 g of pyridine dissolved in 287.5 g of water (final) while maintaining the temperature at 40 ° C. and stirring at a stirring rotation speed of 120 rpm (final). (Equivalent to 2.5% by mass of the obtained catalyst powder), and the mixture was capped and stirred for 10 minutes to obtain an aqueous silica solution. Put ammonium paramolybdate in 476.7g to another lidded container _{_{_{_{[(NH 4) 6 Mo 7}}}} O 24 · 4H 2 O], was dissolved in warm water at 60 ° C. of 850.8G. After cooling to 45 ° C., 35.8 g of a 15% by mass aqueous ammonia solution was added to obtain a molybdenum aqueous solution. Furthermore, 51.6 g of bismuth nitrate into another lidded container _{_{_{[Bi (NO 3) 3 ·}}} 5H 2 O], cerium nitrate _{_{_{96.1g [Ce (NO 3) 3}}} · 6H 2 O], of 171.2g iron nitrate _{_{_{[Fe (NO 3) 3 ·}}} 9H 2 O], 203.4g of nickel nitrate _{_{_{[Ni (NO 3) 2 ·}}} 6H 2 O], cobalt nitrate _{_{258.8g [Co (NO 3) 2}} · 6H 2 O] and 5.0 g of rubidium nitrate [RbNO ₃ ] were dissolved in 13.3% by mass of nitric acid (393.3 g) and kept at 40 ° C. to obtain a nitrate aqueous solution. The aqueous molybdenum solution was added to the aqueous silica solution while maintaining the temperature at 40 ° C. and stirring at a stirring rotation speed of 200 rpm to obtain an aqueous silica / molybdenum solution. After stirring for 5 minutes, the mixture was kept at 40 ° C. and the nitrate aqueous solution was added to the silica / molybdenum aqueous solution while stirring at a stirring rotation speed of 250 rpm to prepare a raw material slurry. A precursor slurry was prepared by stirring the raw slurry at 40 ° C for 45 minutes. The obtained precursor slurry was dried using a rotating disk type spray dryer to obtain dried particles. At this time, the air temperature at the dryer inlet was 270 ° C, and the air temperature at the outlet was 155 ° C. The rotation speed of the disk was set at 12,500 rpm. When TG-DTA measurement was performed using the obtained dried particles, the calorific value calculated from the area of the exothermic peak having a maximum value in the range of 200 ° C. to 300 ° C. was 175 J / g, and the weight loss rate was 26. 0.0%. The dried particles were held at 200 ° C. for 5 minutes, heated from 200 ° C. to 450 ° C. at a rate of 2.5 ° C./minute, and denitrated by holding at 450 ° C. for 20 minutes. The denitrated dry particles were calcined at 595 ° C. for 2 hours to obtain an ammoxidation catalyst. The obtained ammoxidation catalyst is supplied in advance to a fluidized reaction vessel, and propylene, molecular oxygen, and ammonia are reacted (ammoxidation reaction) while circulating the catalyst in the fluidized reaction vessel, Acrylonitrile was produced and the molar ratio of ammonia / propylene (N / C), the molar ratio of air / propylene (A / C), and the acrylonitrile yield were determined. Table 1 shows the results.

[Example 10]
Catalyst (metal oxide) in which a metal oxide whose composition is represented by Mo _12.00 Bi _0.47 Ce _0.99 Fe _1.88 Ni _3.08 Co _3.90 Rb _0.15 is supported on silica. : 60% by mass, silica: 40% by mass) according to the following procedure.
First, 1333 g of ammonium polyacrylate dissolved in 287.5 g of water was placed in a vessel with a lid, and 1333 g of silica sol containing 30% by mass of SiO ₂ was kept at 40 ° C. and stirred at 120 rpm. (Equivalent to 1.5% by mass of the finally obtained catalyst powder) was added, and the mixture was capped and stirred for 10 minutes to obtain an aqueous silica solution. Put ammonium paramolybdate in 476.7g to another lidded container _{_{_{_{[(NH 4) 6 Mo 7}}}} O 24 · 4H 2 O], was dissolved in warm water at 60 ° C. of 850.8G. After cooling to 45 ° C., 35.8 g of a 15% by mass aqueous ammonia solution was added to obtain a molybdenum aqueous solution. Furthermore, 51.6 g of bismuth nitrate into another lidded container _{_{_{[Bi (NO 3) 3 ·}}} 5H 2 O], cerium nitrate _{_{_{96.1g [Ce (NO 3) 3}}} · 6H 2 O], of 171.2g iron nitrate _{_{_{[Fe (NO 3) 3 ·}}} 9H 2 O], 203.4g of nickel nitrate _{_{_{[Ni (NO 3) 2 ·}}} 6H 2 O], cobalt nitrate _{_{258.8g [Co (NO 3) 2}} · 6H 2 O] and 5.0 g of rubidium nitrate [RbNO ₃ ] were dissolved in 13.3% by mass of nitric acid (393.3 g) and kept at 40 ° C. to obtain a nitrate aqueous solution. The aqueous molybdenum solution was added to the aqueous silica solution while maintaining the temperature at 40 ° C. and stirring at a stirring rotation speed of 200 rpm to obtain an aqueous silica / molybdenum solution. After stirring for 5 minutes, the mixture was kept at 40 ° C. and the nitrate aqueous solution was added to the silica / molybdenum aqueous solution while stirring at a stirring rotation speed of 250 rpm to prepare a raw material slurry. A precursor slurry was prepared by stirring the raw slurry at 40 ° C for 45 minutes. The obtained precursor slurry was dried using a rotating disk type spray dryer to obtain dried particles. At this time, the air temperature at the dryer inlet was 270 ° C, and the air temperature at the outlet was 155 ° C. The rotation speed of the disk was set at 12,500 rpm. When TG-DTA measurement was performed using the obtained dried particles, the calorific value calculated from the area of the exothermic peak having a maximum value in the range of 200 ° C. to 300 ° C. was 62 J / g, and the weight loss rate was 27. 0.8%. The dried particles were held at 200 ° C. for 5 minutes, heated from 200 ° C. to 450 ° C. at a rate of 2.5 ° C./minute, and denitrated by holding at 450 ° C. for 20 minutes. The denitrated dry particles were calcined at 595 ° C. for 2 hours to obtain an ammoxidation catalyst. The obtained ammoxidation catalyst is supplied in advance to a fluidized reaction vessel, and propylene, molecular oxygen, and ammonia are reacted (ammoxidation reaction) while circulating the catalyst in the fluidized reaction vessel, Acrylonitrile was produced and the molar ratio of ammonia / propylene (N / C), the molar ratio of air / propylene (A / C), and the acrylonitrile yield were determined. Table 1 shows the results.

[Example 11]
Catalyst (metal oxide) in which a metal oxide whose composition is represented by Mo _12.00 Bi _0.47 Ce _0.99 Fe _1.88 Ni _3.08 Co _3.90 Rb _0.15 is supported on silica. : 55% by mass, silica: 45% by mass) was produced by the following procedure.
First, 1500 g of silica sol containing 30% by mass of SiO ₂ was placed in a container with a lid, kept at 40 ° C., and stirred at a rotation speed of 120 rpm while oxalic acid dihydrate 25 dissolved in 287.5 g of water. 0.0 g (equivalent to 2.5% by mass of the finally obtained catalyst powder) was added, and the mixture was capped and stirred for 10 minutes to obtain an aqueous silica solution. Put ammonium paramolybdate in 437.0g to another lidded container _{_{_{_{[(NH 4) 6 Mo 7}}}} O 24 · 4H 2 O], was dissolved in warm water at 60 ° C. of 779.9G. After cooling to 45 ° C., 29.8 g of a 15% by mass aqueous ammonia solution was added to obtain a molybdenum aqueous solution. Further, 47.3 g of bismuth nitrate [Bi (NO ₃ ) ₃ .5H ₂ O], 88.1 g of cerium nitrate [Ce (NO ₃ ) ₃ .6H ₂ O], and 157.0 g of another container with a lid were placed. iron nitrate _{_{_{[Fe (NO 3) 3 ·}}} 9H 2 O], 186.5g of nickel nitrate _{_{_{[Ni (NO 3) 2 ·}}} 6H 2 O], cobalt nitrate _{_{237.3g [Co (NO 3) 2}} · 6H 2 O] and 4.6 g of rubidium nitrate [RbNO ₃ ] were dissolved in 392.2 g of 16.6% by mass of nitric acid, and kept at 40 ° C. to obtain a nitrate aqueous solution. The aqueous molybdenum solution was added to the aqueous silica solution while maintaining the temperature at 40 ° C. and stirring at a stirring rotation speed of 200 rpm to obtain an aqueous silica / molybdenum solution. After stirring for 5 minutes, the mixture was kept at 40 ° C. and the nitrate aqueous solution was added to the silica / molybdenum aqueous solution while stirring at a stirring rotation speed of 250 rpm to prepare a raw material slurry. A precursor slurry was prepared by stirring the raw slurry at 40 ° C for 45 minutes. The obtained precursor slurry was dried using a rotating disk type spray dryer to obtain dried particles. At this time, the air temperature at the dryer inlet was 270 ° C, and the air temperature at the outlet was 155 ° C. The rotation speed of the disk was set at 12,500 rpm. When TG-DTA measurement was performed using the obtained dried particles, the calorific value calculated from the area of the exothermic peak having a maximum value in the range of 200 ° C. to 300 ° C. was 75 J / g, and the weight loss was 26. 9%. The dried particles were held at 200 ° C. for 5 minutes, heated from 200 ° C. to 450 ° C. at a rate of 2.5 ° C./minute, and denitrated by holding at 450 ° C. for 20 minutes. The denitrated dry particles were calcined at 595 ° C. for 2 hours to obtain an ammoxidation catalyst. The obtained ammoxidation catalyst is supplied in advance to a fluidized reaction vessel, and propylene, molecular oxygen, and ammonia are reacted (ammoxidation reaction) while circulating the catalyst in the fluidized reaction vessel, Acrylonitrile was produced and the molar ratio of ammonia / propylene (N / C), the molar ratio of air / propylene (A / C), and the acrylonitrile yield were determined. Table 1 shows the results.

[Example 12]
Catalyst (metal oxide) in which a metal oxide whose composition is represented by Mo _12.00 Bi _0.47 Ce _0.99 Fe _1.88 Ni _3.08 Co _3.90 Rb _0.15 is supported on silica. : 60% by mass, silica: 40% by mass) according to the following procedure.
First, 1333 g of silica sol containing 30% by mass of SiO ₂ was put in a container with a lid, kept at 40 ° C., and stirred at a rotation speed of 120 rpm while oxalic acid dihydrate 25 dissolved in 287.5 g of water. 0.0 g (equivalent to 2.5% by mass of the finally obtained catalyst powder) was added, and the mixture was capped and stirred for 10 minutes to obtain an aqueous silica solution. Put ammonium paramolybdate in 476.7g to another lidded container _{_{_{_{[(NH 4) 6 Mo 7}}}} O 24 · 4H 2 O], was dissolved in warm water at 60 ° C. of 850.8G. After cooling to 45 ° C., 35.8 g of a 15% by mass aqueous ammonia solution was added to obtain a molybdenum aqueous solution. Furthermore, 51.6 g of bismuth nitrate into another lidded container _{_{_{[Bi (NO 3) 3 ·}}} 5H 2 O], cerium nitrate _{_{_{96.1g [Ce (NO 3) 3}}} · 6H 2 O], of 171.2g iron nitrate _{_{_{[Fe (NO 3) 3 ·}}} 9H 2 O], 203.4g of nickel nitrate _{_{_{[Ni (NO 3) 2 ·}}} 6H 2 O], cobalt nitrate _{_{258.8g [Co (NO 3) 2}} · 6H 2 O] and 5.0 g of rubidium nitrate [RbNO ₃ ] were dissolved in 13.3% by mass of nitric acid (393.3 g) and kept at 40 ° C. to obtain a nitrate aqueous solution. The aqueous molybdenum solution was added to the aqueous silica solution while maintaining the temperature at 40 ° C. and stirring at a stirring rotation speed of 200 rpm to obtain an aqueous silica / molybdenum solution. After stirring for 5 minutes, the mixture was kept at 40 ° C. and the nitrate aqueous solution was added to the silica / molybdenum aqueous solution while stirring at a stirring rotation speed of 250 rpm to prepare a raw material slurry. A precursor slurry was prepared by stirring the raw slurry at 40 ° C for 45 minutes. The obtained precursor slurry was dried using a rotating disk type spray dryer to obtain dried particles. At this time, the air temperature at the dryer inlet was 280 ° C, and the air temperature at the outlet was 160 ° C. The rotation speed of the disk was set at 12,500 rpm. When TG-DTA measurement was performed using the obtained dried particles, the calorific value calculated from the area of the exothermic peak having a maximum value in the range of 200 ° C. to 300 ° C. was 73 J / g, and the weight loss was 27. 5%. The dried particles were held at 200 ° C. for 5 minutes, heated from 200 ° C. to 450 ° C. at a rate of 2.5 ° C./minute, and denitrated by holding at 450 ° C. for 20 minutes. The denitrated dry particles were calcined at 595 ° C. for 2 hours to obtain an ammoxidation catalyst. The obtained ammoxidation catalyst is supplied in advance to a fluidized reaction vessel, and propylene, molecular oxygen, and ammonia are reacted (ammoxidation reaction) while circulating the catalyst in the fluidized reaction vessel, Acrylonitrile was produced and the molar ratio of ammonia / propylene (N / C), the molar ratio of air / propylene (A / C), and the acrylonitrile yield were determined. Table 1 shows the results.

[Comparative Example 1]
Catalyst (metal oxide) in which a metal oxide whose composition is represented by Mo _12.00 Bi _0.47 Ce _0.99 Fe _1.88 Ni _3.08 Co _3.90 Rb _0.15 is supported on silica. : 60% by mass, silica: 40% by mass) according to the following procedure.
First, 1333 g of silica sol containing 30% by mass of SiO ₂ was placed in a container with a lid, kept at 40 ° C., and stirred at a stirring rotation speed of 120 rpm to obtain a silica aqueous solution. Put ammonium paramolybdate in 476.7g to another lidded container _{_{_{_{[(NH 4) 6 Mo 7}}}} O 24 · 4H 2 O], was dissolved in warm water at 70 ° C. of 850.8G. It was kept at 70 ° C. to obtain a molybdenum aqueous solution. Furthermore, 51.6 g of bismuth nitrate into another lidded container _{_{_{[Bi (NO 3) 3 ·}}} 5H 2 O], cerium nitrate _{_{_{96.1g [Ce (NO 3) 3}}} · 6H 2 O], of 171.2g iron nitrate _{_{_{[Fe (NO 3) 3 ·}}} 9H 2 O], 203.4g of nickel nitrate _{_{_{[Ni (NO 3) 2 ·}}} 6H 2 O], cobalt nitrate _{_{258.8g [Co (NO 3) 2}} · 6H 2 O] and 5.0 g of rubidium nitrate [RbNO ₃ ] were dissolved in 13.3% by mass of nitric acid (393.3 g) and kept at 40 ° C. to obtain a nitrate aqueous solution. The aqueous molybdenum solution was added to the aqueous silica solution while maintaining the temperature at 40 ° C. and stirring at a stirring rotation speed of 200 rpm to obtain an aqueous silica / molybdenum solution. After stirring for 5 minutes, the mixture was kept at 40 ° C. and the nitrate aqueous solution was added to the silica / molybdenum aqueous solution while stirring at a stirring rotation speed of 250 rpm to prepare a raw material slurry. A precursor slurry was prepared by stirring the raw slurry at 40 ° C for 45 minutes. The obtained precursor slurry was dried using a rotating disk type spray dryer to obtain dried particles. At this time, the air temperature at the dryer inlet was 270 ° C, and the air temperature at the outlet was 155 ° C. The rotation speed of the disk was set at 12,500 rpm. When TG-DTA measurement was performed using the obtained dried particles, the calorific value calculated from the area of the exothermic peak having a maximum value in the range of 200 ° C to 300 ° C was 43 J / g, and the weight loss rate was 25. 0.0%. The dried particles were held at 200 ° C. for 5 minutes, heated from 200 ° C. to 450 ° C. at a rate of 2.5 ° C./minute, and denitrated by holding at 450 ° C. for 20 minutes. The denitrated dry particles were calcined at 595 ° C. for 2 hours to obtain an ammoxidation catalyst. The obtained ammoxidation catalyst is supplied in advance to a fluidized reaction vessel, and propylene, molecular oxygen, and ammonia are reacted (ammoxidation reaction) while circulating the catalyst in the fluidized reaction vessel, Acrylonitrile was produced and the molar ratio of ammonia / propylene (N / C), the molar ratio of air / propylene (A / C), and the acrylonitrile yield were determined. Table 1 shows the results.

[Comparative Example 2]
Catalyst (metal oxide) in which a metal oxide whose composition is represented by Mo _12.00 Bi _0.47 Ce _0.99 Fe _1.88 Ni _3.08 Co _3.90 Rb _0.15 is supported on silica. : 60% by mass, silica: 40% by mass) according to the following procedure.
First, 1333 g of silica sol containing 30% by mass of SiO ₂ was placed in a container with a lid, kept at 40 ° C., and stirred at a stirring rotation speed of 120 rpm to obtain a silica aqueous solution. Put ammonium paramolybdate in 476.7g to another lidded container _{_{_{_{[(NH 4) 6 Mo 7}}}} O 24 · 4H 2 O], was dissolved in warm water at 60 ° C. of 850.8G. It was cooled to 45 ° C. to obtain a molybdenum aqueous solution. Furthermore, 51.6 g of bismuth nitrate into another lidded container _{_{_{[Bi (NO 3) 3 ·}}} 5H 2 O], cerium nitrate _{_{_{96.1g [Ce (NO 3) 3}}} · 6H 2 O], of 171.2g iron nitrate _{_{_{[Fe (NO 3) 3 ·}}} 9H 2 O], 203.4g of nickel nitrate _{_{_{[Ni (NO 3) 2 ·}}} 6H 2 O], cobalt nitrate _{_{258.8g [Co (NO 3) 2}} · 6H 2 O] and 5.0 g of rubidium nitrate [RbNO ₃ ] were dissolved in 13.3% by mass of nitric acid (393.3 g) and kept at 40 ° C. to obtain a nitrate aqueous solution. The aqueous molybdenum solution was added to the aqueous silica solution while maintaining the temperature at 40 ° C. and stirring at a stirring rotation speed of 200 rpm to obtain an aqueous silica / molybdenum solution. After stirring for 5 minutes, the mixture was kept at 40 ° C. and the nitrate aqueous solution was added to the silica / molybdenum aqueous solution while stirring at a stirring rotation speed of 250 rpm to prepare a raw material slurry. A precursor slurry was prepared by stirring the raw slurry at 40 ° C for 45 minutes. The obtained precursor slurry was dried using a rotating disk type spray dryer to obtain dried particles. At this time, the air temperature at the dryer inlet was 270 ° C, and the air temperature at the outlet was 155 ° C. The rotation speed of the disk was set at 12,500 rpm. When TG-DTA measurement was performed using the obtained dried particles, the calorific value calculated from the area of the exothermic peak having a maximum value in the range of 200 ° C. to 300 ° C. was 42 J / g, and the weight loss rate was 36. 0.0%. The dried particles were held at 200 ° C. for 5 minutes, heated from 200 ° C. to 450 ° C. at a rate of 2.5 ° C./minute, and denitrated by holding at 450 ° C. for 20 minutes. The denitrated dry particles were calcined at 595 ° C. for 2 hours to obtain an ammoxidation catalyst. The obtained ammoxidation catalyst is supplied in advance to a fluidized reaction vessel, and propylene, molecular oxygen, and ammonia are reacted (ammoxidation reaction) while circulating the catalyst in the fluidized reaction vessel, Acrylonitrile was produced and the molar ratio of ammonia / propylene (N / C), the molar ratio of air / propylene (A / C), and the acrylonitrile yield were determined. Table 1 shows the results.

[Comparative Example 3]
Catalyst (metal oxide) in which a metal oxide whose composition is represented by Mo _12.00 Bi _0.47 Ce _0.99 Fe _1.88 Ni _3.08 Co _3.90 Rb _0.15 is supported on silica. : 60% by mass, silica: 40% by mass) according to the following procedure.
First, 1333 g of silica sol containing 30% by mass of SiO ₂ was put in a container with a lid, kept at 40 ° C., and stirred at a rotation speed of 120 rpm while oxalic acid dihydrate 25 dissolved in 287.5 g of water. 0.0 g (equivalent to 2.5% by mass of the finally obtained catalyst powder) was added, and the mixture was capped and stirred for 10 minutes to obtain an aqueous silica solution. Put ammonium paramolybdate in 476.7g to another lidded container _{_{_{_{[(NH 4) 6 Mo 7}}}} O 24 · 4H 2 O], was dissolved in warm water at 60 ° C. of 850.8G. After cooling to 45 ° C., 35.8 g of a 15% by mass aqueous ammonia solution was added to obtain a molybdenum aqueous solution. Furthermore, 51.6 g of bismuth nitrate into another lidded container _{_{_{[Bi (NO 3) 3 ·}}} 5H 2 O], cerium nitrate _{_{_{96.1g [Ce (NO 3) 3}}} · 6H 2 O], of 171.2g iron nitrate _{_{_{[Fe (NO 3) 3 ·}}} 9H 2 O], 203.4g of nickel nitrate _{_{_{[Ni (NO 3) 2 ·}}} 6H 2 O], cobalt nitrate _{_{258.8g [Co (NO 3) 2}} · 6H 2 O] and 5.0 g of rubidium nitrate [RbNO ₃ ] were dissolved in 13.3% by mass of nitric acid (393.3 g) and kept at 40 ° C. to obtain a nitrate aqueous solution. The aqueous molybdenum solution was added to the aqueous silica solution while maintaining the temperature at 40 ° C. and stirring at a stirring rotation speed of 200 rpm to obtain an aqueous silica / molybdenum solution. After stirring for 5 minutes, the mixture was kept at 40 ° C. and the nitrate aqueous solution was added to the silica / molybdenum aqueous solution while stirring at a stirring rotation speed of 250 rpm to prepare a raw material slurry. A precursor slurry was prepared by stirring the raw slurry at 40 ° C for 45 minutes. The obtained precursor slurry was dried using a rotating disk type spray dryer to obtain dried particles. At this time, the air temperature at the dryer inlet was 305 ° C, and the air temperature at the outlet was 195 ° C. The rotation speed of the disk was set at 12,500 rpm. When TG-DTA measurement was performed using the obtained dried particles, the calorific value calculated from the area of the exothermic peak having a maximum value in the range of 200 ° C. to 300 ° C. was 40 J / g, and the weight loss rate was 23. 0.2%. The dried particles were held at 200 ° C. for 5 minutes, heated from 200 ° C. to 450 ° C. at a rate of 2.5 ° C./minute, and denitrated by holding at 450 ° C. for 20 minutes. The denitrated dry particles were calcined at 595 ° C. for 2 hours to obtain an ammoxidation catalyst. The obtained ammoxidation catalyst is supplied in advance to a fluidized reaction vessel, and propylene, molecular oxygen, and ammonia are reacted (ammoxidation reaction) while circulating the catalyst in the fluidized reaction vessel, Acrylonitrile was produced and the molar ratio of ammonia / propylene (N / C), the molar ratio of air / propylene (A / C), and the acrylonitrile yield were determined. Table 1 shows the results.

[Comparative Example 4]
Catalyst (metal oxide) in which a metal oxide whose composition is represented by Mo _12.00 Bi _0.47 Ce _0.99 Fe _1.88 Ni _3.08 Co _3.90 Rb _0.15 is supported on silica. : 60% by mass, silica: 40% by mass) according to the following procedure.
First, 1333 g of silica sol containing 30% by mass of SiO ₂ was put in a container with a lid, kept at 40 ° C., and stirred at a rotation speed of 120 rpm while oxalic acid dihydrate 25 dissolved in 287.5 g of water. 0.0 g (equivalent to 2.5% by mass of the finally obtained catalyst powder) was added, and the mixture was capped and stirred for 10 minutes to obtain an aqueous silica solution. Put ammonium paramolybdate in 476.7g to another lidded container _{_{_{_{[(NH 4) 6 Mo 7}}}} O 24 · 4H 2 O], was dissolved in warm water at 60 ° C. of 850.8G. It was cooled to 45 ° C. to obtain a molybdenum aqueous solution. Furthermore, 51.6 g of bismuth nitrate into another lidded container _{_{_{[Bi (NO 3) 3 ·}}} 5H 2 O], cerium nitrate _{_{_{96.1g [Ce (NO 3) 3}}} · 6H 2 O], of 171.2g iron nitrate _{_{_{[Fe (NO 3) 3 ·}}} 9H 2 O], 203.4g of nickel nitrate _{_{_{[Ni (NO 3) 2 ·}}} 6H 2 O], cobalt nitrate _{_{258.8g [Co (NO 3) 2}} · 6H 2 O] and 5.0 g of rubidium nitrate [RbNO ₃ ] were dissolved in 13.3% by mass of nitric acid (393.3 g) and kept at 40 ° C. to obtain a nitrate aqueous solution. The aqueous molybdenum solution was added to the aqueous silica solution while maintaining the temperature at 40 ° C. and stirring at a stirring rotation speed of 200 rpm to obtain an aqueous silica / molybdenum solution. After stirring for 5 minutes, the mixture was kept at 40 ° C. and the nitrate aqueous solution was added to the silica / molybdenum aqueous solution while stirring at a stirring rotation speed of 250 rpm to prepare a raw material slurry. A precursor slurry was prepared by stirring the raw slurry at 40 ° C for 45 minutes. The obtained precursor slurry was dried using a rotating disk type spray dryer to obtain dried particles. At this time, the air temperature at the dryer inlet was 270 ° C, and the air temperature at the outlet was 155 ° C. The rotation speed of the disk was set at 12,500 rpm. When TG-DTA measurement was performed using the obtained dried particles, the calorific value calculated from the area of the exothermic peak having a maximum value in the range of 200 ° C. to 300 ° C. was 41 J / g, and the weight loss rate was 24. 0.1%. The dried particles were held at 200 ° C. for 5 minutes, heated from 200 ° C. to 450 ° C. at a rate of 2.5 ° C./minute, and denitrated by holding at 450 ° C. for 20 minutes. The denitrated dry particles were calcined at 595 ° C. for 2 hours to obtain an ammoxidation catalyst. The obtained ammoxidation catalyst is supplied in advance to a fluidized reaction vessel, and propylene, molecular oxygen, and ammonia are reacted (ammoxidation reaction) while circulating the catalyst in the fluidized reaction vessel, Acrylonitrile was produced and the molar ratio of ammonia / propylene (N / C), the molar ratio of air / propylene (A / C), and the acrylonitrile yield were determined. Table 1 shows the results.

As is clear from Table 1, all of the ammoxidation catalysts obtained in Examples 1 to 12 were able to synthesize acrylonitrile in high yield. On the other hand, although the catalysts for ammoxidation obtained in Comparative Examples 1 to 3 had the same metal composition as Examples 1 to 12, the yield of acrylonitrile was lower than those of Examples 1 to 12. Furthermore, although the catalyst for ammoxidation obtained in Comparative Example 4 had a metal composition similar to those of Examples 1 to 12, the yield of acrylonitrile was lower than that of Examples 1 to 12.

This application is based on a Japanese patent application filed on August 24, 2018 (Japanese Patent Application No. 2018-157543), the contents of which are incorporated herein by reference.

Claims

A preparation step of preparing a precursor slurry to be a catalyst precursor,
A drying step of drying the precursor slurry to obtain dry particles,
A firing step of firing the dried particles to obtain an ammoxidation catalyst,
Has,
The calorific value calculated from the area value of the exothermic peak having a maximum value in the range of 200 ° C. to 300 ° C. observed by TG-DTA measurement of the dried particles before firing is 45 J / g or more and 200 J / g or less. And a method for producing an ammoxidation catalyst.
The method for producing an ammoxidation catalyst according to claim 1, wherein the calorific value is 80 J / g or more and 200 J / g or less.
The method for producing an ammoxidation catalyst according to claim 1 or 2, wherein the ammoxidation catalyst includes a composite metal oxide having a composition represented by the following general formula (1).
Mo 12 Bi a Fe b X c Y d Z e O f (1)
(In the formula (1), X is one or more elements selected from the group consisting of nickel, cobalt, magnesium, calcium, zinc, strontium, and barium, and Y is cerium, chromium, lanthanum, neodymium, yttrium, praseodymium, samarium, Z represents one or more elements selected from the group consisting of potassium, rubidium and cesium, and a represents the atomic ratio of bismuth to 12 atoms of molybdenum. 0.1 ≦ a ≦ 2.0, b represents the atomic ratio of iron to 12 atoms of molybdenum, 0.1 ≦ b ≦ 3.0, and c represents the atomic ratio of X to 12 atoms of molybdenum. 0.1 ≦ c ≦ 10.0, d represents the atomic ratio of Y to 12 molybdenum atoms, and 0.1 ≦ d ≦ 3. 0, e indicates the atomic ratio of Z to 12 atoms of molybdenum, 0.01 ≦ e ≦ 2.0, f indicates the atomic ratio of oxygen to 12 atoms of molybdenum, and the valence of other elements present This is the number of oxygen atoms required to satisfy the requirement.)
The method for producing an ammoxidation catalyst according to any one of claims 1 to 3, wherein the ammoxidation catalyst contains a carrier, and the content of the carrier in the ammoxidation catalyst is 35 to 45% by mass.
The method for producing an ammoxidation catalyst according to any one of claims 1 to 4, wherein the preparation step of preparing the precursor slurry includes adding aqueous ammonia or water to the raw material.
The catalyst for ammoxidation according to any one of claims 1 to 5, wherein in the preparation step of preparing the precursor slurry, the raw material includes a molybdenum solution, and includes adding ammonia water or water to the molybdenum solution. Production method.
7. The drying step of drying the precursor slurry to obtain dried particles, wherein the inlet air temperature of the dryer is maintained at 180 to 280 ° C. and the outlet temperature is maintained at 100 to 170 ° C. 2. The method for producing an ammoxidation catalyst according to claim 1.
The firing step for firing the dried particles to obtain an ammoxidation catalyst includes a denitration treatment before the main firing, wherein the denitration treatment is performed at 150 to 450 ° C. for 1.5 to 3 hours. 8. The method for producing an ammoxidation catalyst according to any one of items 7 to 7.
The method for producing an ammoxidation catalyst according to any one of claims 1 to 8, wherein in the firing step of firing the dried particles to obtain an ammoxidation catalyst, the main firing temperature is 550 to 650 ° C.
A preparation step of preparing a precursor slurry to be a catalyst precursor,
A drying step of drying the precursor slurry to obtain dry particles,
A firing step of firing the dried particles to obtain an ammoxidation catalyst,
The step of supplying the catalyst for ammoxidation in advance to a fluidized reaction vessel and, while circulating the catalyst in the fluidized reaction vessel, reacting propylene, molecular oxygen, and ammonia to obtain acrylonitrile,
The calorific value calculated from the area value of the exothermic peak having a maximum value in the range of 200 ° C. to 300 ° C. observed by TG-DTA measurement of the dried particles before firing is 45 J / g or more and 200 J / g or less. And a method for producing acrylonitrile.
The method for producing acrylonitrile according to claim 10, wherein the calorific value is 80 J / g or more and 200 J / g or less.
The source of molecular oxygen is air;
The acrylonitrile according to claim 10 or 11, wherein the molar ratio of ammonia and air to propylene is in the range of 1 / (0.8 to 1.4) / (7 to 12) in the ratio of propylene / ammonia / air. Production method.
The source of molecular oxygen is air;
The acrylonitrile according to claim 10 or 11, wherein the molar ratio of ammonia and air to propylene is in the range of 1 / (0.9 to 1.3) / (8 to 11) in the ratio of propylene / ammonia / air. Production method.
The acrylonitrile according to any one of claims 10 to 13, wherein a temperature at which propylene, molecular oxygen, and ammonia are reacted in the presence of the ammoxidation catalyst is in a temperature range of 350 to 550 ° C. Manufacturing method.
The acrylonitrile according to any one of claims 10 to 13, wherein a temperature at which propylene, molecular oxygen, and ammonia are reacted in the presence of the ammoxidation catalyst is in a temperature range of 400 to 500 ° C. Manufacturing method.
The method for producing acrylonitrile according to any one of claims 10 to 15, wherein the catalyst for ammoxidation contains a composite metal oxide having a composition represented by the following general formula (1).
Mo 12 Bi a Fe b X c Y d Z e O f (1)
(In the formula (1), X is one or more elements selected from the group consisting of nickel, cobalt, magnesium, calcium, zinc, strontium, and barium, and Y is cerium, chromium, lanthanum, neodymium, yttrium, praseodymium, samarium, Z represents one or more elements selected from the group consisting of potassium, rubidium and cesium, and a represents the atomic ratio of bismuth to 12 atoms of molybdenum. 0.1 ≦ a ≦ 2.0, b represents the atomic ratio of iron to 12 atoms of molybdenum, 0.1 ≦ b ≦ 3.0, and c represents the atomic ratio of X to 12 atoms of molybdenum. 0.1 ≦ c ≦ 10.0, d represents the atomic ratio of Y to 12 molybdenum atoms, and 0.1 ≦ d ≦ 3. 0, e indicates the atomic ratio of Z to 12 atoms of molybdenum, 0.01 ≦ e ≦ 2.0, f indicates the atomic ratio of oxygen to 12 atoms of molybdenum, and the valence of other elements present This is the number of oxygen atoms required to satisfy the requirement.)
The process for producing acrylonitrile according to any one of claims 10 to 16, wherein the catalyst for ammoxidation contains a carrier, and the content of the carrier in the catalyst for ammoxidation is 35 to 45% by mass.
18. The method for producing acrylonitrile according to claim 10, wherein the step of preparing the precursor slurry includes adding aqueous ammonia or water to the raw material.
The method for producing acrylonitrile according to any one of claims 10 to 18, wherein in the preparation step of preparing the precursor slurry, the raw material includes a molybdenum solution, and the method includes adding ammonia water or water to the molybdenum solution.
20. The drying step of drying the precursor slurry to obtain dried particles, wherein the inlet air temperature of the dryer is maintained at 180 to 280 ° C. and the outlet temperature is maintained at 100 to 170 ° C. Item 2. The method for producing acrylonitrile according to item 1.
The calcination step of calcining the dried particles to obtain an ammoxidation catalyst includes a denitration treatment before the main calcination, and the denitration treatment is performed at 150 to 450 ° C. for 1.5 to 3 hours. 21. The method for producing acrylonitrile according to any one of 20.
The method for producing acrylonitrile according to any one of claims 10 to 21, wherein in the firing step of firing the dried particles to obtain an ammoxidation catalyst, the main firing temperature is 550 to 650 ° C.