JP2002233768A - Ammoxidation catalyst and method for producing nitrile compound using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a nitrile compound by an ammoxidation reaction using a fluidized bed reactor, to obtain a target nitrile compound in high yield, and to reduce catalyst loss. . SOLUTION: The fluidized bed has a particle content of 95 mass% or more in a particle size range of 5 to 150 μm and a particle content of 3 to 30 mass% in a particle size range of 20 to 30 μm. Ammoxidation catalyst for reaction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an ammoxidation catalyst for a fluidized bed reaction and a method for producing a nitrile compound using the same. More specifically, the target nitrile yield is increased, and the ammoxidation catalyst for carrying out the economically advantageous ammoxidation reaction by reducing the catalyst loss and the nitrile compound from alcohol, hydrocarbon and the like using the same are used. Regarding the manufacturing method. Nitrile compounds are industrially extremely useful compounds as intermediate materials for producing synthetic fibers, synthetic resins, medicines, agricultural chemicals and the like.

[0002]

2. Description of the Related Art In the production of nitrile compounds by the ammoxidation reaction of hydrocarbons and the like using a fluidized bed reactor, as a method for increasing the target nitrile yield, catalyst components and catalyst preparation for improving the performance of the catalyst are used. To improve the law,
Improving the fluidization condition is a necessary condition. Fluidized bed reactors have problems such as the formation of air bubbles and insufficient contact between the raw material gas and the catalyst, and the backmixing of the gas and the excessive progress of the reaction. Conventionally, various proposals for so-called fluidized state improvement have been made. As the fluidization state improvement method, broadly speaking,
There are methods for improving the reactor structure and the reaction operation method, and methods for focusing on the physical properties of the catalyst, particularly the particle size distribution of the catalyst. The present invention is intended to improve the particle size distribution of an ammoxidation catalyst used in a fluidized bed reactor in the latter viewpoint.

The prior art relating to the particle size distribution of the catalyst used in a fluidized bed reactor can be roughly classified into four types. The first method defines the entire particle size range of the catalyst. For example, Japanese Patent Publication No. 50-24941 discloses that the particle size of an ammoxidation or oxidation catalyst containing antimony is 1 to 500 m. Is described as desirable. However, this method only gives a rough guide,
This alone does not provide a sufficient effect. The second method is to subdivide the entire particle size range and define the particle content in each section. For example, Japanese Patent Publication No. 60-13746 discloses that the particle size range of a catalyst containing large particles exceeding 360 m is determined. It has been proposed to divide the amount of particles in each of the seven sections into a specific ratio. Although such a method is strict, it requires a large amount of labor and cost for adjusting the particle size distribution, and has a very large problem in practical use.

The third method focuses on a specific particle size range. It is well known that in carrying out a catalytic reaction in a fluidized bed reactor, it is important to contain a sufficient proportion of fine particles. For example, "The Fluidized Bed Reactor" edited by the Chemical Engineering Association, page 24 (1987, Chemical Industry Co., Ltd.)
States that the content of particles having a particle size of 44 μm or less is desirably 20 to 40%. In addition, Ikeda et al., On page 99 of “Recent Chemical Engineering Fluidized Bed Engineering” edited by The Chemical Engineering Association, exemplify the particle size distribution of a typical fluidized bed catalytic reaction as follows.

[0005]

[Table 1] These suggest the importance of containing a large number of fine particles of -40 to 45 µm, and more particularly -20 µm. However, even under such conditions, an industrial-scale reactor is greatly affected by a fluidized state, and thus has problems such as not being able to obtain expected reaction results and increasing catalyst scattering loss. .

The fourth method is to contain a small amount of extremely fine particles. For example, Japanese Patent Application Laid-Open No. Hei 9-18764 discloses a method for producing maleic anhydride having a particle size of 10 m.
The following fine particles were added to the particles in the reactor during the operation period.
It is disclosed that 10 ppm or more is added on average per day. However, since the fine particles of 10 m or less have a strong adhesion, it is not easy to uniformly disperse the particles in the entire reactor and maintain a constant ratio in a large reactor.
It is very difficult to apply to actual driving operation. As described above, any of the conventional techniques relating to the particle size distribution are inadequate in effect, or the actual operation is difficult, and a great deal of labor is required.

[0007]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, which become significant when the size of the reactor is increased, to obtain a high nitrile yield and reduce catalyst loss in a fluidized bed ammonic acid reaction. The present invention proposes an ammoxidation catalyst for a fluidized bed reaction, which economically advantageously produces the target nitrile compound.

The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, by maintaining the content of particles in a specific range of particle size in a specific value in an ammoxidation catalyst for a fluidized bed reaction, a high nitrile yield can be obtained. The present invention has been found to reduce the catalyst loss. That is, the first aspect of the present invention is that the particle content in the range of 5 to 150 μm is 95% by mass or more, and the particle size is 20 to 30 μm.
The gist of the present invention is an ammoxidation catalyst for fluidized bed reaction, wherein the particle content in the range of m is 3 to 30% by mass.

A second aspect of the present invention is characterized in that an ammoxidation reaction is carried out using an alcohol, a hydrocarbon and / or a heterocyclic compound as a raw material in a fluidized bed reactor in the presence of the ammoxidation catalyst. The gist is a method for producing a nitrile compound.

[0010]

Hereinafter, the present invention will be described in more detail. Fluidized bed reactors have excellent features such as easy temperature control and catalyst replacement during operation.
The raw material gas forms bubbles and moves up the catalyst layer, so that the contact between the gas and the catalyst is insufficient, and there is back mixing of the gas and the reaction proceeds excessively, resulting in lower reaction results than the fixed layer . In order to obtain the desired nitrile in a high yield, it is necessary to reduce the bubble diameter and make sufficient contact between the gas and the catalyst,
It is an essential requirement to improve the so-called fluidized state, such as reducing the backmixing of the gas.

According to the present invention, using a fine powder-based catalyst,
The objective can be achieved by a relatively simple method of setting specific fine particles in the particle size distribution to specific values. In general, in a catalyst system containing fine particles, a large amount of catalyst is transported by gas, so even if the catalyst is collected by a cyclone or the like, the scattering loss increases, and the fluidized state due to the adhesion of the fine particles changes. Deterioration and reaction performance decrease. In the present invention, the target nitrile compound can be obtained in a high yield without causing such a problem of the fine powder system.

The ammoxidation catalyst used in the present invention has a particle size of 5
It is characterized in that the content of particles in the range of 150 to 150 μm is 95% by mass or more. Fine particles of 5 μm or less or 150
When the content of large particles having a size of μm or more increases, the fluidization state deteriorates. The increase in the fine particles causes a stagnation in a part of the catalyst layer, causing a gas drift. The increase in large particles increases the diameter of the generated bubbles.

Further, the ammoxidation catalyst used in the present invention has a particle size of 20 to 30 μm in order to increase the yield of the nitrile compound.
The particle content in the range of m is 3 to 30% by mass. Conventionally, as described above, the particle content of 40 to 45 μm or less is important. However, the effect of improving the nitrile yield by containing about 30 to 40 μm particles is small. Has been found to be important. However, particles having a particle size of 20 μm or less tend to be scattered in industrial equipment and cannot be retained in a reactor for a long period of time, so that an increase in the content of particles having a particle size of 20 μm or less causes an increase in catalyst loss. If the particle size in the range of 20 to 30 μm is less than 3% by mass, the effect of fine particles is not obtained, and the fluidized state may be deteriorated. If the amount of the particles in the range of 20 to 30 μm exceeds 30% by mass, the fluidization state is good, but the scattering loss of the catalyst becomes unexpectedly large, which is not practical.

The present invention is intended to improve the flow state by maintaining the particle size distribution of the catalyst at a specific value, thereby improving the reaction yield and reducing the scattering loss. Because it is for expressing performance,
The composition of the ammoxidation catalyst used in the present invention is not limited at all. For example, JP-B-36-5870, JP-B-37-13460, and JP-B-37-14.
No. 075, JP-A-49-58100, JP-A-51-10200, JP-B-51-33888, JP-B-53-18014, and JP-B-57-26.
592, JP-A-1-257125, JP-A-4-1-18051, JP-A-7-3228441, and JP-A-10-251012 and the like. Metal oxides containing molybdenum and bismuth, Antimony and metal oxides containing tin, iron or uranium are used for the ammoxidation of methanol, propylene and isobutylene. Further, for example, Japanese Patent Application Laid-Open No. 1-2686
No. 68, JP-A-5-279313, JP-A-1
Japanese Patent Application Laid-Open No. 1-239725 and JP-A-11-246504
In the publication, metal oxides containing molybdenum, vanadium, tellurium and niobium, vanadium, antimony and phosphorus, tungsten, or metal oxides containing iron and molybdenum are used for the ammoxidation reaction of propane and isobutane. Furthermore, Japanese Patent Publication No. 6-29231 discloses iron,
It is disclosed that metal oxides containing antimony, vanadium and chromium can be used for the ammoxidation reaction of chlorotoluenes.

[0015] In the present invention, a catalyst system containing at least one selected from the group consisting of iron, antimony, molybdenum and vanadium as an essential component is preferably used.

The main raw materials used in the present invention are not particularly limited, such as alcohols, hydrocarbons and / or heterocyclic compounds, as long as they are usually used in an ammoxidation reaction. Specifically, alcohols such as methanol and t-butanol, and hydrocarbons such as propylene, propane, isobutylene, isobutane, toluene,
Representative examples of heterocyclic compounds such as chlorotoluenes include picolines. Here, hydrocyanic acid from methanol, acrylonitrile from propylene and / or propane, isobutylene, isobutane and / or
Alternatively, methacrylonitrile is produced from t-butanol, benzonitrile is produced from toluene, the corresponding chlorobenzonitrile is produced from chlorotoluenes, and the corresponding cyanopyridines such as nicotinonitrile are produced from picolines. These main raw materials used in the present invention may be used alone or in combination of two or more.

In the ammoxidation reaction of the present invention, ammonia and an oxygen-containing gas, and if necessary, steam and / or an inert gas are supplied to the reactor together with the above-mentioned main raw materials such as alcohol, hydrocarbon and / or heterocyclic compound. Then, the target nitrile compound is produced by reacting in the presence of the ammoxidation catalyst of the present invention. Air is usually used as the oxygen-containing gas.

The reaction conditions for producing the nitrile compound of the present invention vary depending on the type of the raw material and the catalyst to be ammoxidized, but are generally in the following ranges. The molar ratio of the raw material gas supplied to the reactor is in the range of oxygen: ammonia: hydrocarbon, etc. = 0.5-5: 0.5-3: 1,
Preferably, it is in the range of 1-3: 0.7-1.5: 1. The reaction temperature ranges from 350 to 550 ° C., the contact time ranges from 0.1 to 30 seconds, preferably from 0.5 to 20 seconds, and the reaction pressure ranges from atmospheric pressure to 200 kPa.

[0019]

Next, the present invention will be described more specifically with reference to examples and comparative examples. The conversion and the nitrile yield are defined by the following equations. Conversion (%) = (number of moles of main raw materials such as reacted hydrocarbons)
/ (Number of moles of supplied main material such as hydrocarbon) × 100 Nitrile yield (%) = (number of moles of generated nitrile compound) / (number of moles of supplied main material such as hydrocarbon) × 10
0

Example 1 Production of acrylonitrile by ammoxidation of propylene was performed using a fluidized bed reactor. The reactor is made of stainless steel having an inner diameter of 0.2 m and a height of 6 m, and is provided with two cyclones arranged in series at the upper part of the reactor to collect the catalyst. The catalyst collected by the cyclone passes through each pipe. To the catalyst layer in the reactor. The ammoxidation catalyst is produced according to the method described in Catalyst 4 (Silica-supported metal oxide composed of iron, antimony, molybdenum, tungsten, tellurium, copper and sodium) in Examples of Japanese Patent Publication No. 57-26592. did. The particle size distribution of the catalyst was -5 μm in mass percent of 0%,
4% for 20 μm, 15% for 20 to 30 μm, 30 to 44
μm 21%, 44-150 μm 60%, +150 μm
m was adjusted to 0%.

70 kg of this catalyst was charged into a reactor, and propylene, ammonia and air were mixed at a molar ratio of 1.0: 1.
The reaction temperature was 435 ° C., supplied at a ratio of 1: 10.5.
The reactor outlet pressure was adjusted to 50 kPa and the contact time was adjusted to 3.5 seconds to perform a continuous reaction for 500 hours. The reaction results showed a propylene conversion rate of 98.10 hours after the start of the reaction.
5%, acrylonitrile yield 82.5%, and after 500 hours, propylene conversion was 98.0%, and acrylonitrile yield was 82.1%. After confirming the reaction results after 500 hours, the reaction was stopped and the catalyst was recovered from the reactor. The catalyst loss was 0.5 kg.

(Comparative Example 1) Using the same reactor as in Example 1, the particle size distribution of the catalyst was -5 μm: 0%, 5 to 20 μm: 0%, 20 to 30 μm: 1%, and 30 to 44 μm: 39%.
%, 44-150 μm was adjusted to 60%, and +150 μm was adjusted to 0%, and an ammoxidation reaction of propylene was performed in the same manner as in Example 1. The reaction results were as follows: 10 hours after the start of the reaction, the propylene conversion rate was 96.8%,
The acrylonitrile yield was 79.3%, and after 500 hours, the propylene conversion was 96.5%, and the acrylonitrile yield was 79.0%. The catalyst loss after 500 hours of reaction is
0.3 kg.

(Comparative Example 2) Using the same reactor as in Example 1, the particle size distribution of the catalyst was -5 μm at 0%, 5-20 μm at 1%, 20-30 μm at 35%, and 30-44 μm at 6%.
%, 44-150 μm was adjusted to 58%, and +150 μm was adjusted to 0%, and an ammoxidation reaction of propylene was performed in the same manner as in Example 1. The reaction results were as follows: 10 hours after the start of the reaction, the propylene conversion rate was 98.8%,
The acrylonitrile yield was 81.4%, and after 500 hours, the conversion of propylene was 95.7%, and the acrylonitrile yield was 78.8%. The catalyst loss after 500 hours of reaction is
It was 5.0 kg.

Example 2 Production of hydrocyanic acid by ammoxidation of methanol was carried out in the same reactor as in Example 1. The ammoxidation catalyst was produced according to the catalyst 1 (silica carrier metal oxide composed of iron, antimony, phosphorus and vanadium) of the example of JP-A-10-251012. The particle size distribution of the catalyst was -5 μm in mass percent of 0.
%, 5 to 20 μm 3%, 20 to 30 μm 10%, 3
22% for 0 to 44 μm, 64% for 44 to 150 μm, +
150 μm was adjusted to 1%.

30 kg of this catalyst was charged into a reactor, and methanol, ammonia, air and steam were mixed at a molar ratio of 1.
The reaction was carried out at a ratio of 0: 1.0: 6.5: 1.0, a reaction temperature of 430 ° C., a reactor outlet pressure of 20 kPa, and a contact time of 1.0 second to perform a continuous reaction for 500 hours. went.
The reaction results were as follows: 10 hours after the start of the reaction, 99.9% methanol conversion, 92.0% hydrocyanic acid yield, 500 hours later, 99.5% methanol conversion, 9% hydrocyanic acid yield
2.3%. After confirming the reaction results after 500 hours, the reaction was stopped and the catalyst was recovered from the reactor. The catalyst loss was 0.4 kg.

Comparative Example 3 Using the same reactor as in Example 2, the particle size distribution of the catalyst was determined to be 0% for -5 μm, 0% for 5 to 20 μm, 1% for 20 to 30 μm, and 35% for 30 to 44 μm.
%, 44-150 μm was adjusted to 63%, and +150 μm was adjusted to 1%, and an ammoxidation reaction of methanol was performed in the same manner as in Example 2. The reaction results were as follows: 10 hours after the start of the reaction, the methanol conversion was 97.0%,
The yield of cyanuric acid was 86.0%, and after 500 hours, the conversion of methanol was 96.5% and the yield of cyanuric acid was 85.3%. 50
The catalyst loss after the reaction for 0 hours was 0.7 kg.

(Consideration of Example) It was found that the acrylonitrile yield was improved when compared with Example 1 and Comparative Example 1 in which -44 μm was equal. Furthermore, it was found that the change in acrylonitrile yield with time was extremely small and the catalyst loss was small as compared with Comparative Example-2 in which -44 µm was almost the same. In addition, when comparing Example 2 with Comparative Example 3 in which -44 μm is almost the same, it was found that the hydrocyanic acid yield was significantly improved.

[0028]

According to the present invention, the desired nitrile compound can be obtained in a high yield, and the catalyst loss can be reduced.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C07C 253/28 C07C 253/28 255/03 255/03 255/08 255/08 255/50 255/50 / / C07B 61/00 300 C07B 61/00 300 (72) Inventor Yoichi Yamagishi 1-6-1, Konan, Minato-ku, Tokyo Mitsubishi Rayon Co., Ltd. F-term (reference) 4G069 AA03 AA11 BA02A BA02B BB06A BB06B BC02B BC26A BC26B BC31B BC54A BC59A BC59B BC60B BC66A BC66B BD05A BD07B BD10B CB53 CB54 CB55 DA08 EA01X EA01Y EA19 EB18X EB18Y 4H006 AA02 AC12 AC54 BA02 BA05 BA12 BA13 BA14 BA15 BA19 BA30 BA35 BA55 BE14 BE30 QN26 Q3026

Claims (4)

[Claims] 1. A fluid having a particle content of 95% by mass or more in a particle size range of 5 to 150 μm and a particle content of 3 to 30% by mass in a particle size range of 20 to 30 μm. Ammoxidation catalyst for bed reaction. 2. The ammoxidation catalyst for a fluidized bed reaction according to claim 1, wherein the ammoxidation catalyst comprises at least one element selected from the group consisting of iron, antimony, molybdenum and vanadium. 3. A nitrile, wherein an ammoxidation reaction is carried out in the presence of the ammoxidation catalyst according to claim 1 or 2, using an alcohol, a hydrocarbon and / or a heterocyclic compound as a raw material using a fluidized bed reactor. Preparation of the compound. 4. The method for producing a nitrile compound according to claim 3, wherein the raw material is at least one selected from the group consisting of methanol, propylene, propane, isobutylene, t-butanol, isobutane, toluene and chlorotoluene. .