JP2010253414A - Catalyst for producing acrylonitrile and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a catalyst for producing acrylonitrile, with which acrylonitrile can be obtained with excellent selectivity in high yield. <P>SOLUTION: The catalyst for producing acrylonitrile, which is used in an ammoxidation reaction of propylene, contains the compound oxide of metals shown by compositional formula (1): Mo<SB>m</SB>Bi<SB>b</SB>Fe<SB>f</SB>Ni<SB>n</SB>Sb<SB>s</SB>W<SB>w</SB>Q<SB>q</SB>A<SB>a</SB>E<SB>e</SB>O<SB>x</SB>(wherein Q is at least one element selected from the group consisting of chromium and indium; A is at least one element selected from the group consisting of potassium, rubidium and cesium; E is at least one element selected from the group consisting of manganese, magnesium, zinc and cerium; m, b, f, n, s, w, q, a and e are atomic ratios of Mo, Bi, Fe, Ni, Sb, W, Q, A and E, respectively, m=10 to 14, b=0.1 to 3, f=0.1 to 3, n=4 to 10, s=0.01 to 3, w=0 to 3, q=0.1 to 2, a=0.01 to 0.5, e=0 to 3; and x is the number of oxygen atoms to be decided by valences of constituent elements other than oxygen) and is characterized in that the ratio Ri=Pi/Ph of the intensity Pi of the diffraction peak (i) of iron antimonate appearing at 2θ=35.0±0.3° to that Ph of the diffraction peak (h) of NiMoO<SB>4</SB>appearing at 2θ=26.5±0.3° is ≤0.05 and the ratio Rj=Pj/Ph of the intensity Pj of the diffraction peak (j) of iron antimonate appearing at 2θ=53.2±0.3° to that Ph of the diffraction peak (h) of NiMoO4 at 2θ=26.5±0.3° is ≤0.03 in the X-ray diffraction patterns to be obtained by using a Cu-Kα radiation as an X ray source. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a catalyst for producing acrylonitrile used for producing acrylonitrile by reacting propylene with ammonia and oxygen in a gas phase and a method for producing the same.

A process for producing acrylonitrile by vapor-phase catalytic oxidation of propylene with molecular oxygen in the presence of ammonia is widely known as an “ammoxidation process” and is currently practiced on an industrial scale.
With the aim of more efficient implementation on an industrial scale, various studies are being conducted on catalysts used in ammoxidation processes. As a catalyst for ammoxidation, those made of composite metal oxides such as Mo—Bi—Fe, Fe—Sb, and Mo—Bi—Fe—Ni are known. Many compositions obtained by adding other components to these essential metals have been studied.
For example, Patent Document 1 discloses a catalyst in which other components are added in addition to molybdenum, bismuth, iron, antimony, nickel, chromium, and potassium.
Moreover, it is thought that the crystal structure of each metal component also affects catalyst performance, and Patent Documents 2 to ₄ disclose catalysts in which iron antimonate FeSbO ₄ is present as a crystal phase in the catalyst.

Japanese Patent No. 4159729 Japanese Patent No. 3142549 Japanese Patent No. 3680115 Japanese Patent No. 3796132 Japanese Patent No. 3875011

  However, when the present inventors examined the catalyst disclosed in the above-mentioned patent document, the catalyst containing iron antimonate has various advantages such as high selectivity of acrylonitrile, but in terms of yield. It turns out that it cannot be said that it is satisfactory. In addition, the preparation of iron antimonate requires a very high temperature, and there is a problem that a complicated process is required to highly disperse iron antimonate at the time of catalyst preparation.

  In view of the above circumstances, the problem to be solved by the present invention is to provide a catalyst for producing acrylonitrile that has a good acrylonitrile selectivity and can obtain acrylonitrile in a high yield.

  As a result of intensive studies on a catalyst containing molybdenum, bismuth, iron, nickel, chromium and / or indium used for the ammoxidation reaction of propylene, the present inventors further contain Sb in addition to these components, and the Sb component Was found to show a high acrylonitrile selectivity and a high acrylonitrile yield, and the present invention was completed.

That is, the present invention is as follows.
[1]
A catalyst for the production of acrylonitrile used in the ammoxidation reaction of propylene, comprising the following compositional formula (1)
_{Mo m Bi b Fe f Ni n} Sb s W w Q q A a E e O x (1)
(Wherein Q is at least one element selected from the group consisting of chromium and indium, A is at least one element selected from the group consisting of potassium, rubidium and cesium, E is a group consisting of manganese, magnesium, zinc and cerium) M, b, f, n, s, w, q, a and e represent the atomic ratio of Mo, Bi, Fe, Ni, Sb, W, Q, A and E, respectively. M = 10-14, b = 0.1-3, f = 0.1-3, n = 4-10, s = 0.01-3, w = 0-3, q = 0.1 2, a = 0.01 to 0.5, e = 0 to 3, and x represents the number of oxygen atoms determined by the valence of a constituent element other than oxygen.) ,
In an X-ray diffraction pattern obtained using CuKα rays as an X-ray source, 2θ = 35.0 ± 0.0.0 with respect to the intensity Ph of the diffraction peak (h) of NiMoO ₄ appearing at a position of 2θ = 26.5 ± 0.3 °. The ratio Pi = Pi / Ph of the intensity Pi of the diffraction peak (i) of iron antimonate appearing at 3 ° is Ri ≦ 0.05,
A catalyst for producing acrylonitrile in which the ratio Rj = Pj / Ph of the diffraction peak (j) of the iron antimonate that appears at 2θ = 53.2 ± 0.3 ° to the intensity Ph is Rj ≦ 0.03.
[2]
The following composition formula (1)
_{Mo m Bi b Fe f Ni n} Sb s W w Q q A a E e O x (1)
(Wherein Q is at least one element selected from the group consisting of chromium and indium, A is at least one element selected from the group consisting of potassium, rubidium and cesium, E is a group consisting of manganese, magnesium, zinc and cerium) M, b, f, n, s, w, q, a and e represent the atomic ratio of Mo, Bi, Fe, Ni, Sb, W, Q, A and E, respectively. M = 10-14, b = 0.1-3, f = 0.1-3, n = 4-10, s = 0.01-3, w = 0-3, q = 0.1 2, a = 0.01 to 0.5, e = 0 to 3, and x represents the number of oxygen atoms determined by the valence of a constituent element other than oxygen. A method for producing a catalyst for producing acrylonitrile, comprising:
(I) a step of preparing a raw material slurry containing a metal component;
(Ii) a step of spray drying the raw material slurry, and (iii) a step of firing the spray-dried particles obtained by the spray drying.
Have
The manufacturing method in which the said process (i) includes the process of preparing the solution containing Sb, Mo, W, and hydrogen peroxide, and the process of mixing the said solution and metal components other than Sb, Mo, and W.
[3]
The following composition formula (1)
_{Mo m Bi b Fe f Ni n} Sb s W w Q q A a E e O x (1)
(Wherein Q is at least one element selected from the group consisting of chromium and indium, A is at least one element selected from the group consisting of potassium, rubidium and cesium, E is a group consisting of manganese, magnesium, zinc and cerium) M, b, f, n, s, w, q, a and e represent the atomic ratio of Mo, Bi, Fe, Ni, Sb, W, Q, A and E, respectively. M = 10-14, b = 0.1-3, f = 0.1-3, n = 4-10, s = 0.01-3, w = 0-3, q = 0.1 2, a = 0.01 to 0.5, e = 0 to 3, and x represents the number of oxygen atoms determined by the valence of constituent elements other than oxygen.) Acrylonitrile having a composite metal oxide A method for producing a production catalyst, comprising:
(I) a step of preparing a raw material slurry containing a metal component;
(Ii) a step of spray drying the raw material slurry, and (iii) a step of firing the spray-dried particles obtained by the spray drying.
Have
The manufacturing method in which the step (i) includes a step of preparing a solution containing Sb and tartaric acid (or tartaric acid and hydrogen peroxide), and a step of mixing the solution and a metal component other than Sb.
[4]
The method according to [3] above, wherein the amount of tartaric acid added is 2 to 15% by mass based on the amount of the catalyst obtained.

  The acrylonitrile production catalyst of the present invention can obtain acrylonitrile with good acrylonitrile selectivity and high yield in the ammoxidation reaction of propylene.

The catalyst XRD diffraction pattern of Example 1, 4, 5, 12, 14 and the comparative examples 1 and 2 is shown.

  Hereinafter, a mode for carrying out the present invention (hereinafter simply referred to as “the present embodiment”) will be described, but the present invention is not limited to the following embodiment. The present invention can be variously modified without departing from the gist thereof.

The catalyst for producing acrylonitrile of the present embodiment is
A catalyst for the production of acrylonitrile used in the ammoxidation reaction of propylene, comprising the following compositional formula (1)
_{Mo m Bi b Fe f Ni n} Sb s W w Q q A a E e O x (1)
(Wherein Q is at least one element selected from the group consisting of chromium and indium, A is at least one element selected from the group consisting of potassium, rubidium and cesium, E is a group consisting of manganese, magnesium, zinc and cerium) M, b, f, n, s, w, q, a and e represent the atomic ratio of Mo, Bi, Fe, Ni, Sb, W, Q, A and E, respectively. M = 10-14, b = 0.1-3, f = 0.1-3, n = 4-10, s = 0.01-3, w = 0-3, q = 0.1 2, a = 0.01 to 0.5, e = 0 to 3, and x represents the number of oxygen atoms determined by the valence of a constituent element other than oxygen.) ,
In an X-ray diffraction pattern obtained using CuKα rays as an X-ray source, 2θ = 35.0 ± 0.0.0 with respect to the intensity Ph of the diffraction peak (h) of NiMoO ₄ appearing at a position of 2θ = 26.5 ± 0.3 °. The ratio Pi = Pi / Ph of the intensity Pi of the diffraction peak (i) of iron antimonate appearing at 3 ° is Ri ≦ 0.05,
A catalyst for producing acrylonitrile in which the ratio Rj = Pj / Ph of the diffraction peak (j) of the iron antimonate that appears at 2θ = 53.2 ± 0.3 ° to the intensity Ph is Rj ≦ 0.03.

The catalyst for producing acrylonitrile of the present embodiment has a composite metal oxide represented by the following composition formula (1).
_{Mo m Bi b Fe f Ni n} Sb s W w Q q A a E e O x (1)

  In the formula, Q is at least one element selected from the group consisting of chromium and indium, A is at least one element selected from the group consisting of potassium, rubidium and cesium, and E is from the group consisting of manganese, magnesium, zinc and cerium. Indicates at least one element selected.

  m, b, f, n, s, w, q, a and e represent atomic ratios of Mo, Bi, Fe, Ni, Sb, W, Q, A and E, respectively, m = 10 to 14, b = 0.1-3, preferably 0.2-2, more preferably 0.3-1, f = 0.1-3, preferably 0.5-2.5, more preferably 1.0-2. 0, n = 4-10, preferably 4.5-8, more preferably 5-6, s = 0.01-3, preferably 0.05-2, more preferably 0.1-1, w = 0-3, preferably 0-2, more preferably 0-1, q = 0.1-2, preferably 0.1-1.5, more preferably 0.1-1.0, a = 0. 01 to 0.5, preferably 0.04 to 0.4, more preferably 0.08 to 0.3, e = 0 to 3, preferably 1 to 3, more preferably 2 to 3.

  x represents the number of oxygen atoms determined by the valence of a constituent element other than oxygen.

  The composite metal oxide represented by the composition formula (1) is an oxide in which each metal is combined, and contains antimony (Sb) in addition to Mo, Bi, Fe, and Ni. The catalyst containing antimony tends to have a higher yield when the production reaction of acrylonitrile is carried out continuously than the catalyst containing no antimony.

  Further, from the viewpoint of improving the selectivity of acrylonitrile, it is preferable that antimony is highly dispersed in the catalyst. Here, when antimony is highly dispersed in the catalyst, the presence of antimony in the catalyst is difficult to confirm by X-ray diffraction of the catalyst described later, but it is confirmed by a method such as fluorescent X-ray (XRF). can do.

  The catalyst for producing acrylonitrile in the present embodiment contains component Q (at least one element selected from the group consisting of chromium and indium) indispensable for obtaining efficient operation and characteristics. When chromium is used alone, it is preferable that q indicating the atomic ratio of the component Q does not exceed 1. The amount of component Q is preferably determined so that the relative content with respect to iron, that is, q / (q + f) is 0.7 or less, more preferably 0.5 or less. More preferably, it is determined to be 3 or less.

  The catalyst in the present embodiment contains tungsten (W) as an optional component. Tungsten can be contained in the range of w = 0 to 3 with respect to the atomic ratio m of Mo = 10 to 14 in order to obtain an effect of improving the reaction activity and selectivity of the catalyst.

  The catalyst in the present embodiment contains component A (at least one element selected from the group consisting of potassium, rubidium and cesium) in order to achieve high selectivity from propylene to acrylonitrile. However, it is a = 0.01-0.5 which shows the atomic ratio of the component A, and the catalyst which contains the component A exceeding this range exists in the tendency for the reaction activity of propylene to become low. When rubidium or cesium is contained as component A, the selectivity of acrylonitrile tends to be higher with a smaller atomic ratio than when potassium is contained.

  The catalyst in the present embodiment includes an optional component E (at least one element selected from the group consisting of manganese, magnesium, zinc, and cerium). Component E affects the reaction activity of the catalyst, stabilization of catalyst performance, and suppression of deterioration. Component E is preferably two or more elements selected from the group consisting of manganese, magnesium, zinc and cerium, and more preferably two or more elements including at least magnesium and cerium. It is presumed that the crystal structure of the composite metal oxide can be stabilized by containing two or more elements including magnesium and cerium.

  The catalyst for acrylonitrile production in the present embodiment contains Fe and Sb, but the crystal phase of iron antimonate cannot be confirmed. The present inventors have found that the selectivity of acrylonitrile is high because Fe and Sb are contained and Sb is highly dispersed in the catalyst. Iron antimonate exhibits diffraction peaks at 2θ = 35.0 ± 0.3 ° and 2θ = 53.2 ± 0.3 ° in an X-ray diffraction pattern obtained using CuKα rays as an X-ray source. The diffraction peak appearing at 2θ = 35.0 ± 0.3 ° corresponds to (101) of iron antimonate, and the diffraction peak appearing at 2θ = 53.2 ± 0.3 ° is iron antimonate. (211).

  The catalyst in the present embodiment does not show these peaks in the X-ray diffraction pattern. This is presumably because iron antimonate is not contained, or even if it is contained, it is in a highly dispersed state and crystals cannot be confirmed. In the present embodiment, the definition of not showing these peaks is as follows. That is, the ratio of the intensity Pi of the diffraction peak (i) appearing at 2θ = 35.0 ± 0.3 ° to the intensity Ph of the diffraction peak (h) appearing at a position of 2θ = 26.5 ± 0.3 ° Ri = Pi / Ph is Ri ≦ 0.05, and the ratio Rj = Pj / Ph of the intensity Pj of the diffraction peak (j) appearing at 2θ = 53.2 ± 0.3 ° with respect to the intensity Ph is Rj ≦ 0.03. Is defined as not showing a peak derived from the crystalline phase of iron antimonate.

The diffraction peak appearing at the position of 2θ = 26.5 ± 0.3 ° corresponds to (220) of NiMoO ₄ . Since the catalyst in the present embodiment shows a NiMoO ₄ peak, the intensity ratio Ri of the peak corresponding to iron antimonate is 0.05 or less and Rj is 0.03 or less on the basis of this intensity. The iron antimonate is not contained, or even if it is contained, it is determined that it is in a highly dispersed state. In addition, the values of Ri and Rj as judgment criteria are the intensity of the peak appearing at 2θ = 53.2 ± 0.3 ° and 2θ = 26.5 ± 0.3 °, respectively, in the X-ray diffraction peak of iron antimonate. Set based on. Since the peak of iron antimonate appears at two locations of 2θ = 35.0 ± 0.3 ° and 2θ = 53.2 ± 0.3 °, Ri is 0.05 or less and Rj is 0.03 or less. However, it is assumed that a peak derived from another metal component appears at any of these positions. However, if iron antimonate is contained, peaks appear in the above-mentioned two places, so that the peak appearing in only one of them can be determined not to be derived from “iron antimonate”. . In other words, 2θ = 35.0 ± 0.3 ° and 2θ = 53.2 ± 0.3 ° derived from “iron antimonate” are used as indices, and the intensity ratio of one peak among them is the above-mentioned. In other words, when “Ri ≦ 0.05 and Rj> 0.03” or “Ri> 0.05 and Rj ≦ 0.03”, iron antimonate is not contained or contained. However, it is determined (defined) that the state is highly dispersed.

In the catalyst in the present embodiment, Sb is highly dispersed, and it is preferable that no peak derived from the crystal phase of the single oxide of Sb is shown. Sb ₂ O ₃ , Sb ₂ O ₄ and Sb ₂ O ₅ are known as single oxides of Sb, and these peaks in the X-ray diffraction pattern are as follows.

2θ intensity ratio
Sb ₂ O ₃ 28.38 ± 0.3 ° 100
28.60 ± 0.3 ° 75
50.53 ± 0.3 ° 20

Sb ₂ O ₄ 27.45 ± 0.3 ° 100
35.02 ± 0.3 ° 70
53.50 ± 0.3 ° 65

Sb ₂ O ₅ 24.92 ± 0.3 ° 100
28.96 ± 0.3 ° 80
30.53 ± 0.3 ° 90
36.11 ± 0.3 ° 70

FeSbO ₄ 27.21 ± 0.3 ° 100
35.01 ± 0.3 ° 71
53.25 ± 0.3 ° 56

Among these, the fact that there is no peak appearing at the position of 30.53 ± 0.3 ° to 53.5 ± 0.3 ° does not contain a single oxide of Sb or is highly dispersed even if contained. Can be used as an indicator.

The measurement conditions for the X-ray diffraction pattern are as follows.
X-ray source: CuKα1 + CuKα2
Detector: Scintillation counter Spectroscopic crystal: Graphite tube Voltage: 40 kV
Tube current: 150 mA
Divergence slit: 1 °
Scattering slit: 1 °
Receiving slit: 0.15mm
Scanning speed: 1 ° / min Sampling width: 0.02 °
Scanning method: 2θ / θ method For detection and analysis of XRD peaks, Material Data. Inc. Jade 6.5.19 can be used.

  When the production of acrylonitrile is carried out industrially, it is desirable that the catalyst has a sufficient strength. Therefore, the above-mentioned composite metal oxide is preferably supported on a support. Examples of the carrier include silica, alumina, titania, silica alumina, silica titania and the like. Among these, a silica support is preferable from the viewpoint of acrylonitrile yield. The catalyst supported on silica has excellent fluidity in the fluidized bed ammoxidation reaction. From the viewpoint of wear resistance, the silica content is preferably 40% by mass or more based on the total amount of the composite metal oxide and silica. Moreover, it is preferable that a silica content is 60 mass% or less from a viewpoint which shows sufficient catalyst activity and favorable selectivity.

The method for producing a catalyst for producing acrylonitrile in the present embodiment,
The following composition formula (1)
_{Mo m Bi b Fe f Ni n} Sb s W w Q q A a E e O x (1)
(Wherein Q is at least one element selected from the group consisting of chromium and indium, A is at least one element selected from the group consisting of potassium, rubidium and cesium, E is a group consisting of manganese, magnesium, zinc and cerium) M, b, f, n, s, w, q, a and e represent the atomic ratio of Mo, Bi, Fe, Ni, Sb, W, Q, A and E, respectively. M = 10-14, b = 0.1-3, f = 0.1-3, n = 4-10, s = 0.01-3, w = 0-3, q = 0.1 2, a = 0.01 to 0.5, e = 0 to 3, and x represents the number of oxygen atoms determined by the valence of a constituent element other than oxygen. A method for producing a catalyst for producing acrylonitrile, comprising:
(I) a step of preparing a raw material slurry containing a metal component;
(Ii) a step of spray drying the raw material slurry, and (iii) a step of firing the spray-dried particles obtained by the spray drying.
Have
The step (i) is a production method including a step of preparing a solution containing Sb, Mo, W and hydrogen peroxide, and a step of mixing the solution with a metal component other than Sb, Mo and W. .

In addition, another method for producing a catalyst for producing acrylonitrile in the present embodiment,
The following composition formula (1)
_{Mo m Bi b Fe f Ni n} Sb s W w Q q A a E e O x (1)
(Wherein Q is at least one element selected from the group consisting of chromium and indium, A is at least one element selected from the group consisting of potassium, rubidium and cesium, E is a group consisting of manganese, magnesium, zinc and cerium) M, b, f, n, s, w, q, a and e represent the atomic ratio of Mo, Bi, Fe, Ni, Sb, W, Q, A and E, respectively. M = 10-14, b = 0.1-3, f = 0.1-3, n = 4-10, s = 0.01-3, w = 0-3, q = 0.1 2, a = 0.01 to 0.5, e = 0 to 3, and x represents the number of oxygen atoms determined by the valence of constituent elements other than oxygen.) Acrylonitrile having a composite metal oxide A method for producing a production catalyst, comprising:
(I) a step of preparing a raw material slurry containing a metal component;
(Ii) a step of spray drying the raw material slurry, and (iii) a step of firing the spray-dried particles obtained by the spray drying.
Have
The step (i) is a production method including a step of preparing a solution containing Sb and tartaric acid (or tartaric acid and hydrogen peroxide), and a step of mixing the solution and a metal component other than Sb. .

  In the production method of the present embodiment, a solution containing Sb is prepared in advance from the viewpoint of highly dispersing Sb in the catalyst. In the present embodiment, the “solution” means that the compound contained therein is in a state of being turbid and free of precipitates because it is dissolved in a solvent. It can be confirmed visually that it is cloudy and has no precipitate.

Since Sb compounds are generally poorly soluble, a solution containing Sb is prepared by the following method (a) or (b).
A solution containing Sb, Mo, W and hydrogen peroxide is prepared by adding (a) Mo compound, W compound and hydrogen peroxide in addition to the Sb compound and heating at 80 ° C. to boiling point or less.
(B) A solution containing Sb and tartaric acid (or tartaric acid and hydrogen peroxide solution) is prepared by adding tartaric acid (or tartaric acid and hydrogen peroxide) and heating at 80 ° C. to the boiling point or less.
Hereinafter, the methods (a) and (b) will be described.

(A) Method of preparing a solution containing Sb, Mo, W and hydrogen peroxide The method of (a) comprises the steps of Sb compound, Mo compound and W compound corresponding to the amount of Sb, Mo and W contained in the catalyst, and excess. This is a method for preparing a solution containing Sb, Mo, W and hydrogen peroxide by adding hydrogen oxide to water and heating at 80 ° C. to the boiling point or less. The order of addition is not particularly limited as long as the Sb compound, Mo compound, W compound, hydrogen peroxide and water are mixed.

  The amount of water for preparing the solution is not particularly limited, and it is not particularly limited as long as it is sufficient to dissolve them sufficiently depending on the amount and type of the Sb compound, Mo compound and W compound. , 100 to 200% by mass relative to the total mass of the Mo compound and the W compound. Hydrogen peroxide may be added in an amount sufficient to sufficiently dissolve the Sb compound, and is preferably 5.0 times the molar amount or more with respect to Sb.

  Examples of the Sb compound include antimony trioxide and antimony pentoxide.

  Examples of the Mo compound include ammonium paramolybdate, ammonium dimolybdate, and ammonium octamolybdate.

  Examples of the W compound include ammonium metatungstate and ammonium paratungstate.

  The formation of a solution containing Sb, Mo, W, and hydrogen peroxide can be determined by visual observation and turbidity, no precipitate, and a transparent state. When the Sb compound remains undissolved and is in a turbid state, or when a precipitate is present, hydrogen peroxide may be added until the turbidity and precipitate are not observed.

  After Sb, Mo, W and hydrogen peroxide are dissolved in water and a transparent solution is obtained, tartaric acid may be further added. The addition of tartaric acid has the advantage of improving the activity and conversion rate of the resulting catalyst. The mode of adding tartaric acid seems to overlap with “(b) a method of preparing a solution containing Sb and tartaric acid (or tartaric acid and hydrogen peroxide)” described later. This method is different from the method (b) in that tartaric acid is added after the Mo, Sb, and W valences coexisting with each other in a dissolved state. That is, Sb is not dissolved by the addition of tartaric acid. The amount of tartaric acid added is not particularly limited, but from the viewpoint of sufficiently obtaining the above-mentioned merits, the amount of tartaric acid is preferably 2 to 15% by mass, more preferably 3 to 3% by mass with respect to the mass of the obtained catalyst. It is 10 mass%, More preferably, it is 4-8 mass%. However, when tartaric acid is added, the Sb / Mo / W / hydrogen peroxide aqueous solution turns blue, and if left for a long time thereafter, a precipitate may be formed. According to the estimation of the present inventors, this discoloration is considered to be caused by tartaric acid acting as a reducing agent and producing molybdenum blue. Even when the color changes to blue in this way, the slurry preparation is completed before the precipitate is formed, and the catalyst activity and acrylonitrile selectivity are compared with the case where tartaric acid is not added by performing spray drying described later. The improvement effect can be obtained.

(B) Method for preparing a solution containing Sb and tartaric acid (or tartaric acid and hydrogen peroxide) The method of (b) is performed by adding Sb compound and tartaric acid corresponding to the amount of Sb contained in the catalyst to water at 80 ° C to In this method, a solution containing Sb and tartaric acid (or tartaric acid and hydrogen peroxide) is prepared by heating at a boiling point or lower. The order of addition is not particularly limited as long as the Sb compound, tartaric acid and water are mixed. Further, Sb compound, tartaric acid, hydrogen peroxide and water may be mixed and heated at 80 ° C. to the boiling point or less. Also in this case, the order of addition is not particularly limited.

  The amount of tartaric acid added is not particularly limited as long as it is an amount capable of dissolving the Sb compound and obtaining a uniform solution, and is preferably 3.0 times the molar amount or more with respect to Sb. In the case where hydrogen peroxide is not used in combination, the amount of tartaric acid is preferably 2 to 15% by mass, more preferably 3%, based on the mass of the obtained catalyst, from the viewpoint of obtaining a catalyst having high activity and selectivity. It is 10 mass%, More preferably, it is 4-8 mass%.

  When tartaric acid and hydrogen peroxide are used in combination, the amount of tartaric acid added can be reduced. In this case, the amount of tartaric acid added is preferably 1.5 to 3.0 times the molar amount of Sb. The preferred amount of tartaric acid is the same as above (when hydrogen peroxide is not used in combination).

  The amount of hydrogen peroxide added is preferably 1.5 times the molar amount relative to Sb. For example, after adding 1.5 times the molar amount of tartaric acid to Sb, a transparent aqueous solution containing a necessary and sufficient acid can be obtained by adding hydrogen peroxide until a transparent solution is obtained.

  Examples of the Sb compound are the same as those mentioned in the method (a) described above.

[Step (i)]
Step (i) in the method for producing an acrylonitrile production catalyst of the present embodiment is a step of preparing a raw material slurry containing a metal component. In step (i), after preparing a solution containing (a) Sb, Mo, W and hydrogen peroxide, or (b) preparing a solution containing Sb and tartaric acid (or tartaric acid and hydrogen peroxide), This solution and other metal components are mixed to obtain a raw material (mixed) slurry. Hereinafter, the method for preparing the raw slurry will be described taking the case where the catalyst contains a silica carrier as an example.

  The raw material of each component of the catalyst other than antimony is preferably a salt soluble in water or nitric acid. The element source of each element of molybdenum, bismuth, iron, nickel, chromium, indium, potassium, rubidium, cesium, manganese, magnesium, zinc and cerium includes ammonium salt, nitrate, hydrochloride, sulfuric acid soluble in water or nitric acid Mention may be made of salts, organic acid salts and inorganic acids. In particular, as an element source of molybdenum and tungsten, each ammonium salt is preferable, and as an element source of bismuth, iron, nickel, chromium, indium, potassium, rubidium, cesium, manganese, magnesium, zinc and cerium, respective nitrates are preferable. . In addition to being easy to handle, nitrates are also preferred in that they do not cause residual chlorine that occurs when hydrochloride is used or residual sulfur that occurs when sulfate is used. Specific examples of raw materials for each component include ammonium paramolybdate, bismuth nitrate, ferric nitrate, nickel nitrate, chromium nitrate, rubidium nitrate, cerium nitrate, and magnesium nitrate. Silica sol is suitable as the silica source. A preferable concentration of the silica sol in a raw material state in which other components are not mixed is 10 to 50% by mass. When the silica sol concentration is small, the concentration of the aqueous solution to be added is increased so that the concentration is suitable for spray drying of the raw material slurry described later. When the silica sol concentration is large, the concentration of the aqueous solution to be added is decreased. can do.

The order of mixing the catalyst components in the preparation of the raw material mixed slurry is not particularly limited, and examples thereof include the following orders (1) and (2).
(1) While stirring the silica sol, a solution containing Sb, Mo, W and hydrogen peroxide prepared by the method (a) is added, and then a compound other than Sb, Mo, W (preferably nitrate) Is added to an aqueous solvent (preferably an aqueous nitric acid solution). Components other than Sb, Mo and W may be added after being mixed in advance and dissolved in an aqueous solvent, or each may be added after dissolved in an aqueous solvent.
(2) When using a solution containing Sb and tartaric acid (or tartaric acid and hydrogen peroxide) prepared by the method of (b), first, an aqueous solution containing Mo and W is added while stirring the silica sol, and then Sb Add a solution of a metal component compound (preferably nitrate) other than Mo and W in an aqueous solvent (preferably an aqueous nitric acid solution), and finally add an aqueous solution containing Sb, tartaric acid (or tartaric acid and hydrogen peroxide). be able to. The compound of the metal component other than Sb, Mo and W may be added to the silica sol without being mixed in advance after dissolving in an aqueous solvent, or an aqueous solution of a compound of a metal component other than Sb, Mo and W, and Sb, An aqueous solution containing tartaric acid (or tartaric acid and hydrogen peroxide) may be mixed and then added to the silica sol.

[Step (ii)]
Step (ii) in the method for producing the acrylonitrile production catalyst of the present embodiment is a step of spray drying the raw material slurry. In this step, spherical fine particles suitable for fluidized bed reaction can be obtained by spray drying the raw material mixed slurry. The spray drying apparatus may be a general one such as a rotary disk type or a nozzle type, and spray drying is performed so as to obtain a catalyst having a preferable particle size as a fluidized bed catalyst by adjusting the conditions. The preferred particle size for the fluidized bed catalyst is 25 to 180 μm. An example of the conditions for obtaining catalyst particles having a preferred particle size is as follows. Using a centrifugal atomizer equipped with a dish-shaped rotor installed in the center of the upper part of the dryer, the inlet air temperature of the dryer is set. Examples include spray drying performed at 250 ° C. and an outlet temperature of 135 ° C.

[Step (iii)]
Step (iii) in the method for producing a catalyst for acrylonitrile production of the present embodiment is a step of firing the spray-dried particles obtained by the spray drying. When the spray-dried particles contain nitric acid, it is desirable to perform denitration treatment before firing. The denitration treatment can be performed by heat treatment at 300 to 450 ° C. for 0.5 to 2.0 hours. In this step, the catalyst is obtained by calcining the spray-dried particles at a temperature of 600 to 800 ° C, preferably 650 to 750 ° C, more preferably 670 to 730 ° C. If the calcination temperature is too low, the reaction activity of propylene increases, but not only the selectivity to acrylonitrile decreases, but also the wear resistance tends to decrease. On the other hand, when the calcination temperature is too high, the reaction activity of propylene decreases and the combustion of ammonia by the following formula tends to increase.

  A suitable firing temperature can be determined from the range of 600 to 800 ° C. by looking at the results of the ammoxidation reaction test. The firing time is usually 1 to 5 hours.

  Using the acrylonitrile production catalyst in the present embodiment, acrylonitrile can be produced by reacting propylene with ammonia and molecular oxygen in the gas phase (gas phase catalytic ammoxidation reaction).

  Propylene and ammonia, which are raw materials for the ammoxidation reaction, do not necessarily have high purity, and industrial grade ones can be used. Air is usually used as the oxygen source. The volume ratio of ammonia and air to propylene is in the range of 1: 0.9 to 1.7: 7 to 11, preferably 1: 1.0 to 1.5: 8 to 10.

  The reaction temperature is in the range of 400 to 460 ° C, preferably 410 to 440 ° C. The reaction pressure can be in the range of normal pressure to 3 atmospheres. The contact time between the raw material mixed gas and the catalyst is 1 to 8 seconds, preferably 2 to 6 seconds.

  Next, the present embodiment will be described more specifically with reference to examples and comparative examples. However, the present embodiment is not limited to the following examples unless it exceeds the gist.

<XRD measurement method>
The XRD of the obtained catalyst was measured using MXP-18A type manufactured by Mac Science. Place the catalyst in a recess (20 mm long, 16 mm wide rectangular shape, 0.2 mm deep) on the surface of the sample table for XRD measurement, press the plate with a flat stainless steel spatula, and flatten the surface. Was prepared. X-ray diffraction was measured under the following conditions.
X-ray source: CuKα1 + CuKα2
Detector: Scintillation counter Spectroscopic crystal: Graphite tube Voltage: 40 kV
Tube current: 150 mA
Divergence slit: 1 °
Scattering slit: 1 °
Receiving slit: 0.15mm
Scanning speed: 1 ° / min Sampling width: 0.02 °
Scanning method: 2θ / θ method XRD peak detection and analysis were performed using Material Data. Inc. Jade 6.5.19. The catalyst XRD diffraction patterns of Examples 1, 4, 5, 12, 14 and Comparative Examples 1 and 2 are shown in FIG. In addition, Table 2 shows the peak intensities of Ph, Pi, and Pj and the intensity ratios Ri and Rj of each catalyst. If no peak is detected, N.I. D. It was written.

[Example 1]
Catalyst 1 containing a composite metal oxide represented by the following composition formula (2) supported on 50% by mass of silica was produced as follows.
Mo _11.50 Bi _0.36 Fe _1.20 Ni _6.20 Sb _0.60 Cr _0.40 Rb _0.20 Mg _2.50 Ce _0.24 O _x (2)
Mixing 717.4 g of water with 357.4 g of ammonium paramolybdate [(NH ₄ ) ₆ Mo ₇ O ₂₄ · 4H ₂ O], 15.4 g of antimony trioxide and 59.9 g of 30% hydrogen peroxide solution Then, an aqueous solution was prepared by stirring for about 75 minutes in a 90 ° C. water bath, and it was visually confirmed that the aqueous solution was yellow and transparent and had no precipitate.

In 398.6 g of 16.6% nitric acid aqueous solution, 30.7 g of bismuth nitrate [Bi (NO ₃ ) ₃ .5H ₂ O], 85.6 g of ferric nitrate [Fe (NO ₃ ) ₃ .9H ₂ O ] 319.6 g of nickel nitrate [Ni (NO ₃ ) ₂ .6H ₂ O], 28.3 g of chromium nitrate [Cr (NO ₃ ) ₃ .9H ₂ O], 18.6 g of cerium nitrate [Ce (NO ₃ ) A mixed solution in which ₃ · 6H ₂ O], 112.9 g of magnesium nitrate [Mg (NO ₃ ) ₂ · 6H ₂ O] and 5.2 g of rubidium nitrate [RbNO ₃ ] were dissolved was prepared.
While stirring 1500 g of 30% silica sol, a previously prepared aqueous solution containing Mo and Sb was added, and a nitric acid mixed solution containing Bi or the like was further added and stirred. The obtained raw material mixture was in the form of a slurry, and the pH was 1.1. The atomization of the slurry was performed using a centrifugal atomizer equipped with a dish-shaped rotor installed in the center of the upper part of the dryer. The slurry was spray-dried while maintaining the inlet air temperature of the dryer at 250 ° C and the outlet temperature at 135 ° C. The obtained dry powder was transferred to a kiln, first denitrated at 350 ° C. for 1 hour, and then calcined at 660 ° C. for 1 hour to obtain a catalyst. As a result of X-ray diffraction of the obtained catalyst, the presence of iron antimonate was not recognized.

[Example 2]
A catalyst 2 containing a composite metal oxide represented by the following composition formula (3) supported on 50% by mass of silica was produced as follows.
Mo _11.50 Bi _0.36 Fe _1.20 Ni _6.20 Sb _0.60 W _0.30 Cr _0.40 Rb _0.20 Mg _2.50 Ce _0.24 O _x (3)
348.0 g of ammonium paramolybdate [(NH ₄ ) ₆ Mo ₇ O ₂₄ · 4H ₂ O], 15.0 g of antimony trioxide, 14.9 g of ammonium metatungstate [(NH ₄ ) ₆ (H ₂ W ₁₂ O ₄₀ ) · 6H ₂ O], 58.3 g of 30% hydrogen peroxide solution were mixed, and the mixture was stirred for about 75 minutes in a 90 ° C. water bath to prepare an aqueous solution. It was visually confirmed that the aqueous solution was yellow and transparent and there was no precipitate.
To 394.3 g of 16.6% nitric acid aqueous solution, 29.9 g of bismuth nitrate [Bi (NO ₃ ) ₃ .5H ₂ O] and 83.3 g of ferric nitrate [Fe (NO ₃ ) ₃ .9H ₂ O 31.2 g of nickel nitrate [Ni (NO ₃ ) ₂ .6H ₂ O], 27.5 g of chromium nitrate [Cr (NO ₃ ) ₃ .9H ₂ O], 18.1 g of cerium nitrate [Ce (NO ₃ ) A mixed solution in which ₃ · 6H ₂ O], 109.9 g of magnesium nitrate [Mg (NO ₃ ) ₂ · 6H ₂ O] and 5.0 g of rubidium nitrate [RbNO ₃ ] were dissolved was prepared.
While stirring 1500 g of 30% silica sol, an aqueous solution containing Mo, Sb and W prepared in advance was added, and a nitric acid mixed solution containing Bi or the like was further added and stirred. The obtained raw material mixture was in the form of a slurry, and the pH was 1.2. The atomization of the slurry was performed using a centrifugal atomizer equipped with a dish-shaped rotor installed in the center of the upper part of the dryer. The slurry was spray-dried while maintaining the inlet air temperature of the dryer at 250 ° C and the outlet temperature at 135 ° C. The obtained dry powder was transferred to a kiln, denitrated at 350 ° C. for 1 hour, and then calcined at 670 ° C. for 1 hour to obtain a catalyst. As a result of X-ray diffraction of the obtained catalyst, the presence of iron antimonate was not recognized.

[Example 3]
A catalyst 3 containing a composite metal oxide represented by the following composition formula (4) supported on 50% by mass of silica was produced as follows.
Mo _11.50 Bi _0.36 Fe _1.20 Ni _6.20 Sb _0.46 Cr _0.40 Rb _0.20 Mg _2.50 Ce _0.24 O _x (4)
243.6 g of water was mixed with 15.6 g of diantimony trioxide [Sb ₂ O ₃ ] and 61.4 g of tartaric acid [C ₄ H ₆ O ₆ ] and stirred for about 5 hours in a 90 ° C. water bath. A dissolved aqueous solution was prepared. It was visually confirmed that the aqueous solution was transparent and there was no precipitate.
To 1500 g of 30% silica sol, a solution prepared by mixing 400.2 g of ammonium paramolybdate [(NH ₄ ) ₆ Mo ₇ O ₂₄ · 4H ₂ O] with 800.5 g of water in advance is added under stirring, and 435 is added in advance. 34.4 g of 16.6% nitric acid aqueous solution, 34.4 g of bismuth nitrate [Bi (NO ₃ ) ₃ .5H ₂ O], 95.9 g of ferric nitrate [Fe (NO ₃ ) ₃ .9H ₂ O] 357.9 g of nickel nitrate [Ni (NO ₃ ) ₂ .6H ₂ O], 31.7 g of chromium nitrate [Cr (NO ₃ ) ₃ .9H ₂ O], 20.8 g of cerium nitrate [Ce (NO ₃ ) ₃ · 6H ₂ O], 126.4 g of magnesium nitrate [Mg (NO ₃ ) ₂ · 6H ₂ O] and 5.8 g of rubidium nitrate [RbNO ₃ ] are added and prepared in advance. 275.3 g of an aqueous solution containing antimony added It was. The obtained raw material mixture was in the form of a slurry, and the pH was 1.2. The atomization of the slurry was performed using a centrifugal atomizer equipped with a dish-shaped rotor installed in the center of the upper part of the dryer. The slurry was spray-dried while maintaining the inlet air temperature of the dryer at 250 ° C and the outlet temperature at 135 ° C. The obtained dry powder was transferred to a kiln, first denitrated at 350 ° C. for 1 hour, and then calcined at 680 ° C. for 1 hour to obtain a catalyst. As a result of X-ray diffraction of the obtained catalyst, the presence of iron antimonate was not recognized.

[Example 4]
A catalyst 4 containing a composite metal oxide represented by the following composition formula (3) supported on 50% by mass of silica was produced as follows.
Mo _11.50 Bi _0.36 Fe _1.20 Ni _6.20 Sb _0.60 W _0.30 Cr _0.40 Rb _0.20 Mg _2.50 Ce _0.24 O _x (3)
48.7 g of diantimony trioxide [Sb ₂ O ₃ ] and 191.4 g of tartaric acid [C ₄ H ₆ O ₆ ] were mixed with 759.9 g of water, and the mixture was stirred for about 5 hours in a 90 ° C. water bath. A dissolved aqueous solution was prepared. It was visually confirmed that the aqueous solution was transparent and there was no precipitate.
To 1500 g of 30% silica sol, a solution in which 348.0 g of ammonium paramolybdate [(NH ₄ ) ₆ Mo ₇ O ₂₄ · 4H ₂ O] was previously mixed with 695.9 g of water was added with stirring. 29.9 g of bismuth nitrate [Bi (NO ₃ ) ₃ .5H ₂ O], 83.3 g of ferric nitrate [Fe (NO ₃ ) ₃ .9H ₂ O] in ₃ g of 16.6% nitric acid aqueous solution 31.2 g of nickel nitrate [Ni (NO ₃ ) ₂ .6H ₂ O], 27.5 g of chromium nitrate [Cr (NO ₃ ) ₃ .9H ₂ O], 18.1 g of cerium nitrate [Ce (NO ₃ ) ₃ · 6H ₂ O], 109.9 g of magnesium nitrate [Mg (NO ₃ ) ₂ · 6H ₂ O] and 5.0 g of rubidium nitrate [RbNO ₃ ] are added and prepared in advance. 312.2 g of aqueous solution containing antimony added It was. The obtained raw material mixture was in the form of a slurry, and the pH was 1.2. The atomization of the slurry was performed using a centrifugal atomizer equipped with a dish-shaped rotor installed in the center of the upper part of the dryer. The slurry was spray-dried while maintaining the inlet air temperature of the dryer at 250 ° C and the outlet temperature at 135 ° C. The obtained dry powder was transferred to a kiln, first denitrated at 350 ° C. for 1 hour, and then calcined at 700 ° C. for 1 hour to obtain a catalyst. As a result of X-ray diffraction of the obtained catalyst, the presence of iron antimonate was not recognized.

[Examples 5 to 14]
Catalysts 5 to 14 having the compositions described in Table 1 were produced in the same manner as in Example 3 (Catalyst 3). The firing temperature of each catalyst is shown in Table 1.

[Comparative Example 1]
Comparative catalyst 1 containing a composite metal oxide represented by the following composition formula (5) supported on 50% by mass of silica was produced as follows.
Mo _11.50 Bi _0.36 Fe _1.20 Ni _6.20 Cr _0.40 Rb _0.20 Mg _2.50 Ce _0.24 O _x (5)
A solution prepared by mixing 375.1 g of ammonium paramolybdate [(NH ₄ ) ₆ Mo ₇ O ₂₄ · 4H ₂ O] with 750 g of water in advance with 1500 g of 30% silica sol was added with stirring, and 368. In 5 g of 16.6% nitric acid aqueous solution, 30.9 g of bismuth nitrate [Bi (NO ₃ ) ₃ .5H ₂ O], 86.1 g of ferric nitrate [Fe (NO ₃ ) ₃ .9H ₂ O], 321.5 g of nickel nitrate [Ni (NO ₃ ) ₂ .6H ₂ O], 28.4 g of chromium nitrate [Cr (NO ₃ ) ₃ .9H ₂ O], 18.7 g of cerium nitrate [Ce (NO ₃ ) ₃ · 6H ₂ O], 113.6 g of magnesium nitrate [Mg (NO ₃ ) ₂ · 6H ₂ O] and 5.19 g of rubidium nitrate [RbNO ₃ ] were added. The obtained raw material mixture was in the form of a slurry, and the pH was 0.3. The atomization of the slurry was performed using a centrifugal atomizer equipped with a dish-shaped rotor installed in the center of the upper part of the dryer. The slurry was spray-dried while maintaining the inlet air temperature of the dryer at 250 ° C and the outlet temperature at 135 ° C. The obtained dry powder was transferred to a kiln, first denitrated at 350 ° C. for 1 hour, and then calcined at 600 ° C. for 1 hour to obtain a catalyst. As a result of X-ray diffraction of the obtained catalyst, since Comparative Catalyst 1 did not contain Sb, the presence of iron antimonate was not recognized.

[Comparative Example 2]
Comparative catalyst 2 containing a composite metal oxide represented by the following composition formula (2) supported on 50% by mass of silica was produced as follows.
Mo _11.50 Bi _0.36 Fe _1.20 Ni _6.20 Sb _0.60 Cr _0.40 Rb _0.20 Mg _2.50 Ce _0.24 O _x (2)
First, an iron antimonate raw material was produced as follows. Previously ion-exchanged water 400g to diantimony trioxide of 31.2g _[Sb 2 _O 3], stirred to prepare an aqueous slurry by adding ferric nitrate 85.7g _{[Fe (NO 3) 3 · 9H} 2 O ] did. 25% aqueous ammonia was added to the slurry while stirring well to adjust the pH to about 2, and the slurry was heated in a water bath for about 3 hours so that the liquid temperature was about 90 ° C. The slurry was atomized on a hot plate using a small atomizer. The slurry was spray-dried while maintaining the surface temperature of the hot plate at 200 ° C. The obtained dry powder was lightly pulverized in a mortar, first fired at 350 ° C. for 1 hour, and then fired at 950 ° C. for 5 hours. The fired particles were pulverized for about 10 hours with an automatic lyker, to obtain a powder. As a result of X-ray diffraction of the obtained powder, the presence of iron antimonate was observed. This powder was used as an iron antimonate raw material powder.

To 1500 g of 30% silica sol, a solution prepared by previously mixing 351.5 g of ammonium paramolybdate [(NH ₄ ) ₆ Mo ₇ O ₂₄ · 4H ₂ O] with 714.8 g of water was added with stirring. 16.6% nitric acid solution of .5G, bismuth nitrate 30.7g _{[Bi (NO 3) 3 · 5H} 2 O ], ferric nitrate 42.8g _{[Fe (NO 3) 3 · 9H} 2 O ] 319.6 g of nickel nitrate [Ni (NO ₃ ) ₂ .6H ₂ O], 28.3 g of chromium nitrate [Cr (NO ₃ ) ₃ .9H ₂ O], 18.6 g of cerium nitrate [Ce (NO ₃ ) ₃ · 6H ₂ O], 112.9 g of magnesium nitrate [Mg (NO ₃ ) ₂ · 6H ₂ O] and 5.16 g of rubidium nitrate [RbNO ₃ ] were added. Further, 25.6 g of iron antimonate raw material powder was added. The obtained raw material mixture was in the form of a slurry, and the pH was 0.4. The atomization of the slurry was performed using a centrifugal atomizer equipped with a dish-shaped rotor installed in the center of the upper part of the dryer. The slurry was spray-dried while maintaining the inlet air temperature of the dryer at 250 ° C and the outlet temperature at 135 ° C. The obtained dry powder was transferred to a kiln, first denitrated at 350 ° C. for 1 hour, and then calcined at 600 ° C. for 1 hour to obtain a catalyst. As a result of X-ray diffraction of the obtained catalyst, the presence of iron antimonate was observed.

[Reference Example 1]
A reference catalyst containing a composite metal oxide represented by the following composition formula (2) supported on 50% by mass of silica was produced as follows.
Mo _11.50 Bi _0.36 Fe _1.20 Ni _6.20 Sb _0.60 Cr _0.40 Rb _0.20 Mg _2.50 Ce _0.24 O _x (2)
A solution in which 357.4 g of ammonium paramolybdate [(NH ₄ ) ₆ Mo ₇ O ₂₄ · 4H ₂ O] was previously mixed with 1500 g of 30% silica sol and 714.7 g of water was added with stirring. 30.7 g of bismuth nitrate [Bi (NO ₃ ) ₃ .5H ₂ O], 85.6 g of ferric nitrate [Fe (NO ₃ ) ₃ .9H ₂ O] 319.6 g of nickel nitrate [Ni (NO ₃ ) ₂ .6H ₂ O], 28.3 g of chromium nitrate [Cr (NO ₃ ) ₃ .9H ₂ O], 18.6 g of cerium nitrate [Ce (NO ₃ ) ₃ · 6H ₂ O], 112.9 g of magnesium nitrate [Mg (NO ₃ ) ₂ · 6H ₂ O] and 5.2 g of rubidium nitrate [RbNO ₃ ] were added, and 15.4 g of 3 pressurizing the diantimony _[Sb 2 _{O 3]} It was. The obtained raw material mixture was in the form of a slurry, and the pH was 0.8. The atomization of the slurry was performed using a centrifugal atomizer equipped with a dish-shaped rotor installed in the center of the upper part of the dryer. The slurry was spray-dried while maintaining the inlet air temperature of the dryer at 250 ° C and the outlet temperature at 135 ° C. The obtained dry powder was transferred to a kiln, first denitrated at 350 ° C. for 1 hour, and then calcined at 610 ° C. for 1 hour to obtain a catalyst.

In the production of the catalysts in Examples 2 to 14, Comparative Examples 1 and 2, and Reference Example 2, the same raw material as that of Catalyst 1 was used as a source of Mo, Bi, Fe, Ni, Cr, Ce, Mg, Sb and SiO _2. Using. When the catalyst component contains tungsten, indium, potassium, cesium, manganese, or zinc, tungsten [(NH ₄ ) ₆ (H ₂ W ₁₂ O ₄₀ ) · 6H ₂ O], indium [In (NO ₃ ) _{3, respectively.}・ Uses 3H ₂ O], potassium nitrate [KNO ₃ ], cesium nitrate [CsNO ₃ ], manganese nitrate [Mn (NO ₃ ) ₂ · 6H ₂ O], zinc nitrate [Zn (NO ₃ ) ₂ · 6H ₂ O] It was. These catalysts were calcined at the temperatures shown in Table 1, respectively.

(Ammoxidation reaction of propylene)
50 cc of catalyst 1 is placed in a 25 mm inner diameter Vycor glass fluidized bed reaction tube containing 12 10-mesh wire meshes at 1 cm intervals. : Ammonia: oxygen: helium volume ratio of 1: 1.2: 1.85: 7.06) was passed at a flow rate of 3.64 cc (NTP equivalent) per second. The results of this reaction were evaluated by propylene conversion, acrylonitrile selectivity, and acrylonitrile yield defined by the following formula, and the values are shown in Table 3.

  For the catalysts 2 to 14 and the comparative catalysts 1 and 2, the same reaction as described above was performed. In these reactions, 9% by volume of propylene in the raw material mixed gas, the volume ratio of ammonia to propylene is fixed at 1: 1.2, and the volume ratio of oxygen to propylene is appropriately selected from the range of 1.8 to 1.9. I went there. Further, the contact time defined by the following formula was appropriately changed according to the propylene reaction activity of each catalyst. The reaction results of each catalyst are shown in Table 3.

here,
V: catalyst amount (cc)
F: Raw material mixed gas flow rate (cc-NTP / sec.)
T: Reaction temperature (° C)

  As is apparent from the results in Table 3, acrylonitrile is obtained with good selectivity and high yield in the ammoxidation reaction of propylene by using the acrylonitrile production catalyst of the present embodiment (Examples 1 to 14). It was possible.

Claims (4)

A catalyst for the production of acrylonitrile used in the ammoxidation reaction of propylene, comprising the following compositional formula (1)
_{Mo m Bi b Fe f Ni n} Sb s W w Q q A a E e O x (1)
(Wherein Q is at least one element selected from the group consisting of chromium and indium, A is at least one element selected from the group consisting of potassium, rubidium and cesium, E is a group consisting of manganese, magnesium, zinc and cerium) M, b, f, n, s, w, q, a and e represent the atomic ratio of Mo, Bi, Fe, Ni, Sb, W, Q, A and E, respectively. M = 10-14, b = 0.1-3, f = 0.1-3, n = 4-10, s = 0.01-3, w = 0-3, q = 0.1 2, a = 0.01 to 0.5, e = 0 to 3, and x represents the number of oxygen atoms determined by the valence of a constituent element other than oxygen.) ,
In an X-ray diffraction pattern obtained using CuKα rays as an X-ray source, 2θ = 35.0 ± 0.0.0 with respect to the intensity Ph of the diffraction peak (h) of NiMoO ₄ appearing at a position of 2θ = 26.5 ± 0.3 °. The ratio Pi = Pi / Ph of the intensity Pi of the diffraction peak (i) of iron antimonate appearing at 3 ° is Ri ≦ 0.05,
A catalyst for producing acrylonitrile in which the ratio Rj = Pj / Ph of the diffraction peak (j) of the iron antimonate that appears at 2θ = 53.2 ± 0.3 ° to the intensity Ph is Rj ≦ 0.03. The following composition formula (1)
_{Mo m Bi b Fe f Ni n} Sb s W w Q q A a E e O x (1)
(Wherein Q is at least one element selected from the group consisting of chromium and indium, A is at least one element selected from the group consisting of potassium, rubidium and cesium, E is a group consisting of manganese, magnesium, zinc and cerium) M, b, f, n, s, w, q, a and e represent the atomic ratio of Mo, Bi, Fe, Ni, Sb, W, Q, A and E, respectively. M = 10-14, b = 0.1-3, f = 0.1-3, n = 4-10, s = 0.01-3, w = 0-3, q = 0.1 2, a = 0.01 to 0.5, e = 0 to 3, and x represents the number of oxygen atoms determined by the valence of a constituent element other than oxygen. A method for producing a catalyst for producing acrylonitrile, comprising:
(I) a step of preparing a raw material slurry containing a metal component;
(Ii) a step of spray drying the raw material slurry, and (iii) a step of firing the spray-dried particles obtained by the spray drying.
Have
The manufacturing method in which the said process (i) includes the process of preparing the solution containing Sb, Mo, W, and hydrogen peroxide, and the process of mixing the said solution and metal components other than Sb, Mo, and W. The following composition formula (1)
_{Mo m Bi b Fe f Ni n} Sb s W w Q q A a E e O x (1)
(Wherein Q is at least one element selected from the group consisting of chromium and indium, A is at least one element selected from the group consisting of potassium, rubidium and cesium, E is a group consisting of manganese, magnesium, zinc and cerium) M, b, f, n, s, w, q, a and e represent the atomic ratio of Mo, Bi, Fe, Ni, Sb, W, Q, A and E, respectively. M = 10-14, b = 0.1-3, f = 0.1-3, n = 4-10, s = 0.01-3, w = 0-3, q = 0.1 2, a = 0.01 to 0.5, e = 0 to 3, and x represents the number of oxygen atoms determined by the valence of constituent elements other than oxygen.) Acrylonitrile having a composite metal oxide A method for producing a production catalyst, comprising:
(I) a step of preparing a raw material slurry containing a metal component;
(Ii) a step of spray drying the raw material slurry, and (iii) a step of firing the spray-dried particles obtained by the spray drying.
Have
The manufacturing method in which the step (i) includes a step of preparing a solution containing Sb and tartaric acid (or tartaric acid and hydrogen peroxide), and a step of mixing the solution and a metal component other than Sb.   The manufacturing method of Claim 3 whose addition amount of the said tartaric acid is 2-15 mass% with respect to the quantity of the catalyst obtained.