JPH0912489A - Production of unsaturated aldehyde and unsaturated carboxylic acid - Google Patents

Abstract

PURPOSE: To suppress the deterioration of a catalyst for a long period and make it possible to reuse the deteriorated catalyst by performing a reaction in the co-presence of an unused complex oxide catalyst with the deteriorated catalyst used for a long period. CONSTITUTION: This method for producing an unsaturated aldehyde and an unsaturated carboxylic acid comprises performing a gas phase catalytic oxidation of propylene, isobutylene or tertiary butanol with molecular oxygen in a fixed bed multi-tubular reaction apparatus, in the co-presence of an unused complex oxide catalyst of the formula (A is Ni and/or Co; B is Mn, Zn, etc.; C is P, Si, etc.; D is K, Cs, etc.; b to f are each 0-10, when a=12; g is 0-2; x is a value decided by the oxidation states of each of the elements) with the deteriorated used catalyst. For example, a method of burning the deteriorated catalyst in the shape of molded body and then filling it blended with the new catalyst, etc., are cited as a method for co-presenting the deteriorated catalyst with the unused new catalyst. Further, the coexistence of molybdenum oxide is preferable in order to supplement molybdenum in the above reaction.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a process for producing unsaturated aldehydes and unsaturated carboxylic acids by subjecting propylene, isobutylene or tertiary butanol to gas-phase catalytic oxidation. More specifically, the present invention relates to a method of suppressing deterioration of catalyst performance by reusing a catalyst whose performance has deteriorated (hereinafter referred to as deteriorated catalyst) when used in a reaction.

[0002]

2. Description of the Related Art Production of acrolein and acrylic acid from propylene by vapor-phase catalytic oxidation reaction using a so-called molybdenum-bismuth complex oxide catalyst, production of methacrolein and methacrylic acid from isobutylene or tertiary butanol, and vaporization. The technology for producing acrylonitrile and methacrylonitrile by phase contact ammoxidation is well known. However, the catalyst of the present system has a problem that, if the reaction is continued for a long time, the reaction activity and the selectivity are deteriorated due to the deterioration of the performance of the catalyst over time.

Several methods have been proposed so far for suppressing the performance deterioration of the composite oxide catalyst. For example, Japanese Patent Publication No. 53-30688 discloses a method of diluting a catalyst in a portion where hot spots are likely to occur with an inactive substance. Further, Japanese Patent Publication No. 63-38331 discloses a plurality of types of catalysts whose activity is controlled by changing the types and / or amounts of alkali metals and thallium group elements that are part of the catalyst components. A method has been proposed in which a highly active catalyst is arranged from the inlet side toward the outlet side.

The method of controlling hot spots by controlling the activity by diluting the catalyst or changing the composition of the catalyst as described above is an effective method of suppressing the volatilization of molybdenum in the catalyst, which is one of the causes of deterioration. However, it is not always an industrially satisfactory method such as deterioration in catalyst performance cannot be suppressed for a long period of time.

Further, since there is no perfect method for extending the life of the catalyst, several methods for regenerating the deteriorated catalyst have been proposed. For example, Japanese Patent Publication No. 6-29502 discloses that
A method of heat-treating at a temperature of 380 to 540 ° C. in an atmosphere substantially consisting of air is disclosed in Japanese Patent Publication No. 70503/1993, in which an oxidizing gas containing molecular oxygen and water vapor is passed through.
A method of heat treatment at a temperature of 00 to 500 ° C. is disclosed. Further, JP-A-5-184945 discloses a regeneration method in which 2 to 10% by weight of a raw material gas inlet portion is removed and the rest is heat-treated at a temperature of 300 to 500 ° C. in a molecular oxygen-containing gas atmosphere. .

It is described that the above-mentioned regeneration method by heat treatment has an effect of repairing the catalyst surface composition changed by the reaction by diffusion from the inside of the solid, but the effect of the regeneration by this is not sufficient, and the method described in Japanese Patent Laid-Open No. 5-184945
As shown in Japanese Patent Laid-Open Publication No. JP-A-2003-187, a portion having a large degree of deterioration such as a gas inlet portion cannot be completely regenerated, and cannot be regenerated many times.

As one of the methods for regenerating a deteriorated catalyst, there is a regeneration method in which molybdenum reduced by volatilization is replenished by some method, as disclosed in JP-A-50-49201 and JP-A-52-52.
No. 131989, Japanese Patent Publication No. 63-33903, etc., the disclosure of specific examples is related to the regeneration of an ammoxidation catalyst of propylene used at high temperature, and in a fixed bed. Propylene made,
No specific regeneration method of the catalyst used for the partial oxidation of isobutylene is shown, and in the disclosed treatment method, molybdenum oxide is active, and regeneration is insufficient or the complex oxide is not used. This will cause ringing, resulting in a decrease in activity and selectivity.

[0008]

Thus, a sufficiently effective method for suppressing the deterioration of the catalyst performance or regenerating the deteriorated catalyst has not been found yet. An object of the present invention is to produce a corresponding unsaturated aldehyde and unsaturated carboxylic acid by subjecting propylene, isobutylene or tertiary butanol to gas phase catalytic oxidation with molecular oxygen in a fixed bed multitubular reactor to produce a catalyst, It is an object of the present invention to provide a method for suppressing deterioration of performance and extending catalyst life.

[0009]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies in order to solve the above problems, and as a result, gas phase catalytic oxidation of propylene, isobutylene or tertiary butanol was carried out to obtain unsaturated aldehydes and unsaturated carboxylic acids. In a method for producing an acid, a compound oxide catalyst unused in a reaction having excellent catalytic activity for the reaction (hereinafter referred to as a new catalyst) is used together with the compound oxide catalyst in the reaction to deteriorate the performance. The present invention has been found out that by reacting in the presence of a catalyst, the catalyst can be reused and the performance deterioration of the catalyst can be suppressed over a long period of time, leading to the present invention.

That is, the present invention has the general formula Moa Bib
Fec Ad Be Cf Dg Ox (wherein Mo, Bi and Fe represent molybdenum, bismuth and iron, respectively, A represents nickel and / or cobalt, and B consists of manganese, zinc, calcium, magnesium, tin and lead. Represents at least one element selected from the group, C represents at least one element selected from the group consisting of phosphorus, boron, arsenic, tellurium, tungsten, antimony and silicon, and D represents potassium, rubidium, cesium And at least one element selected from the group consisting of thallium, where a = 12, 0 <
b ≦ 10, 0 <c ≦ 10, 0 <d ≦ 10, 0 ≦ e ≦ 1
0, 0 ≦ f ≦ 10, 0 <g ≦ 2, and x is a value determined by the oxidation state of each element), propylene in a fixed-bed multitubular reactor, In a method for producing a corresponding unsaturated aldehyde and unsaturated carboxylic acid by vapor-phase catalytic oxidation of isobutylene or tertiary butanol with molecular oxygen, a complex oxide catalyst unused in the reaction and the catalyst are used in the reaction. A method for producing an unsaturated aldehyde and an unsaturated carboxylic acid, which is characterized by reacting in the presence of a catalyst having deteriorated performance.

The present invention is a method for producing acrolein and acrylic acid by vapor-phase catalytic oxidation of propylene with molecular oxygen using a fixed-bed multitubular reactor, and isobutylene or tertiary butanol is vapor-phase contacted with molecular oxygen. It is applied to a method for producing methacrolein and methacrylic acid by oxidation.

In the present invention, the catalyst used is a complex oxide which is usually used for the oxidation or ammoxidation of propylene or isobutylene, and the composition thereof is represented by the above general formula, for example, JP-B-47. -274
No. 90, Japanese Patent Publication No. 47-32044, Japanese Patent Publication No. 4
7-42241. It should be noted that the composition may include an element other than the elements represented by the above general formula.

Specific catalysts used in the present invention include, for example, catalysts having the following composition (excluding oxygen atoms). Mo ₁₂ Bi _0.1-5 Fe _0.5-5 Co _5-10 Cs _0.01-1 Si
_0.1-20 Mo ₁₂ W _0.1-2 Bi _0.1-5 Fe _0.5-5 Co _5-10 Cs
_0.01-1 Si _0.1-20 Mo ₁₂ W _0.1-2 Bi _0.1-5 Fe _0.5-5 Co _5-10 K _0.01-1
Si _0.1-20 Mo ₁₂ Bi _0.1-5 Fe _0.5-5 Co _5-10 Tl _0.01-1 P
_{0.01-2 Si 0.1-20 Mo 12 Bi 0.1-5 Fe} 0.5-5 Ni 5-10 Tl 0.01-1 P
_0.01-2 Si _0.1-20

This composite oxide catalyst has excellent catalytic activity, but if it is used for a long period of time, the performance of the catalyst deteriorates with the passage of reaction time, and the reaction rate, selectivity of the target product, etc. Reaction results are poor. One of the causes is considered to be that part of molybdenum in the catalyst sublimes and escapes due to high temperature. The present inventors have previously proposed a method in which molybdenum oxide, which is substantially inactive in this reaction, coexists with at least the catalyst on the inlet side of the raw material, as an effect of suppressing this catalyst deterioration (Japanese Patent Laid-Open No. 1548585). .

In this method, deterioration of the catalyst is mainly brought about by volatilization of the molybdenum component at the inlet, and in order not to decrease the reaction yield, it is necessary to coexist in the form of substantially inactive molybdenum oxide in this reaction. It was found that there is. Since molybdenum oxide is an inert diluent by itself, using it on the inlet side is one of the methods for suppressing the activity on the inlet side to a low level. %, It is necessary to coexist with molybdenum oxide, while a relatively small amount, for example 2 to 20%, is sufficient to suppress deterioration.

The method of the present invention achieves the purpose of suppressing catalyst deterioration by using, as a diluent for controlling the activity, a deteriorated catalyst which is a complex oxide of the same kind but whose performance has deteriorated due to a long-term reaction. Is what you are trying to do.
In addition, coexistence of molybdenum oxide for supplementing molybdenum is more effective.

The deteriorated catalyst can be used as a diluent as it is when only the reaction activity is decreased and the selectivity of the reaction is not decreased, but when the selectivity is decreased and the activity of the deteriorated catalyst is decreased. When it is desired to control the temperature, it is desirable to re-fire and use. The amount of the deteriorated catalyst to be coexisted is not particularly limited, but when the deteriorated catalyst is crushed and molded with a new catalyst, it is usually 5 to 7 relative to the new catalyst.
0 wt%, when using the deteriorated catalyst as it is,
Usually, it is 6 to 80% by volume with respect to the new catalyst. Although the firing temperature of the deteriorated catalyst is not particularly limited, it is usually 40
0-700 ° C. It is possible to control the activity of the mixed catalyst layer by the amount of the deteriorated catalyst and / or the firing temperature of the deteriorated catalyst.

The method of coexisting the deteriorated catalyst with the new catalyst is not particularly limited, and the deteriorated catalyst is calcined in the form of a molded body and mixed and filled with the molded new catalyst and more preferably with the molded body of molybdenum oxide. , A method of using a catalyst obtained by crushing a molded body of a deteriorated catalyst extracted from a reactor, mixing it with a new catalyst powder, more preferably with a molybdenum oxide powder, and tableting, extruding or carrying it out. good.

The composition of the deteriorated catalyst to be coexisted is not necessarily the same as that of the new catalyst as long as it is within the above range. For example, the deteriorated catalyst used for the vapor phase catalytic oxidation of isobutylene is the vapor phase of propylene. You may coexist with the new catalyst used for catalytic oxidation.

The position where the deteriorated catalyst is made to coexist with the new catalyst and the filling method are not particularly limited except that they are made to coexist at least in the reaction gas inlet portion, and they may be made to coexist throughout the entire catalyst layer. You may coexist only. Alternatively, the activity may be continuously changed and the activity may be gradually increased from the inlet to the outlet. At least the method of coexisting in the vicinity of the hot spot at the inlet where the catalyst is likely to deteriorate is more effective.

A catalyst whose activity is controlled by changing the amount of alkali metal or the like is different in the activity deterioration behavior due to long-term operation. For example, a catalyst containing a large amount of alkali metal at the inlet side becomes a catalyst containing a small amount of alkali metal at the outlet side. Compared with this, there is a possibility that the rate of decrease in activity is large, and that long-term operation causes only a decrease in activity on the inlet side and new hot spots appear on the layer on the outlet side.

On the other hand, in the catalyst whose activity is controlled by mixing the deteriorated catalyst, the deteriorated catalyst and the new catalyst have basically the same composition, and therefore the behavior of the change with time of the activity is the same. Such problems are unlikely to occur.

The reaction conditions for the gas phase catalytic oxidation reaction of propylene or isobutylene with molecular oxygen can be carried out by a conventionally known method. For example, a reaction temperature of 280 to 400
Although the reaction temperature may be reduced at ℃, the reaction pressure is usually atmospheric pressure to 5
Atm, oxygen / olefin (molar ratio) is 1 to 3, and space velocity SV is 500 to 5000 / H.

[0024]

Industrial Applicability According to the present invention, the performance deterioration of the composite oxide catalyst in the gas phase catalytic oxidation reaction of propylene, isobutylene or tertiary butanol can be suppressed for a longer period of time than before, and the deteriorated catalyst can be reused. It has great industrial significance.

[0025]

The present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.
The reaction rate (%), selectivity (%), and yield (%) are defined as follows. Reaction rate (%) = (mol of reacted olefin / supplied olefin
Number of moles) × 100 selectivity (%) = (number of moles of product / number of moles of reacted olefin)
× 100 yield (%) = (moles of product / moles of olefin fed)
× 100

[0026] Example 1 was dissolved [the composite oxide prepared in Catalyst] ammonium molybdate _{[(NH4) 6 Mo 7 O 24} · 4H 2 O ] 11500g warm water 37.6L, further 20% silica sol (S
1630 g of iO ₂ ) is added, and this is designated as solution A. Cobalt nitrate _{[Co (NO 3) 2 · 6H} 2 O ] 11080g and ferric nitrate _{[Fe (NO 3) 3 · 9H} 2 O ] 440
0 g and cesium nitrate (CsNO ₃ ) 53 g in warm water 2
It is dissolved in 0 L and designated as solution B. 60 to 3.2 L of pure water
% Nitric acid 750 g was added, and bismuth nitrate [Bi (NO ₃ )
₃ · 5H ₂ O] was dissolved 2640G, which the C solution. Next, solution B and solution C are mixed.

While stirring the liquid A, the mixed liquid of the liquid B and the liquid C is added to obtain a slurry. This is concentrated to dryness, and then salt-decomposed at 200 to 250 ° C. under air flow. After that, it was crushed, extruded into a cylindrical shape having an outer diameter of 5 mmφ, an inner diameter of 2 mmφ and a height of 6 mmH, and calcined at 460 ° C. for 6 hours to obtain catalyst A (new catalyst). The catalyst composition excluding oxygen is Mo ₁₂ Bi ₁ Fe.
₂ Co ₇ Cs _0.05 Si ₁ .

Propylene was used in the production of acrylic acid by catalytic vapor-phase oxidation of propylene with a catalyst having the same composition, and a deteriorated catalyst having deteriorated catalytic performance was calcined at 600 ° C. as a molded body and pulverized. 20 parts of this powder and 100 parts of the catalyst precursor powder after salt decomposition and before firing were mixed and extrusion molded into the same shape. This was calcined at 460 ° C. for 6 hours to obtain a catalyst B.

[Reaction] Inner diameter 30 mmφ, height 6000 m
In the mH reaction tube, the catalyst B was used as a catalyst on the side of the raw material gas inlet.
1.15 L, followed by 2.3 L of catalyst A, starting at a salt bath temperature of 325 ° C., propylene: air: nitrogen:
SV = 130 at a molar ratio of steam = 1: 8: 3: 1.5
The reaction was carried out under conditions of 0 h ^-1 and inlet pressure of 2.8 atm.
Table 1 shows the results.

[0030]

[Table 1]

Comparative Example 1 The catalyst A prepared in Example 1 was diluted and filled in the raw material gas inlet side. That is, catalyst A 0.8L and magnetic ring 0.3
5 L was mixed and filled, and 2.3 L of the catalyst A was filled on the outlet side, and the reaction was carried out in the same manner as in Example 1. Table 2 shows the results. Comparative Example 1 has a larger decrease in the total yield of acrolein and acrylic acid.

[0032]

[Table 2]

Example 2 Ammonium molybdate (NH 4) ₆ Mo ₇ O.4H
₂ O was calcined in air at 630 ° C. for 3 hours to obtain MoO ₃ .
90 parts of the catalyst precursor powder after salt decomposition obtained in Example 1, 10 parts of this MoO ₃ and 20 parts of deteriorated catalyst powder calcined at 550 ° C. were mixed and extruded into the same shape. This was calcined at 460 ° C. for 6 hours to obtain a catalyst C. This catalyst C
The gas inlet side was filled with 1.15 L, and the catalyst A was placed on the outlet side.
2.3 L was filled and the reaction was carried out in the same manner as in Example 1. Table 3 shows the results. The change in the salt bath temperature was very slight, and no decrease in the reaction yield was observed.

[0034]

[Table 3]

Continuation of front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication C07C 45/37 C07C 45/37 47/22 9049-4H 47/22 A 9049-4H J 57/055 9450-4H 57/055 Z // C07B 61/00 300 C07B 61/00 300 (72) Inventor Koichi Nagai 5-1 Sokai-cho, Niihama-shi, Ehime Sumitomo Chemical Co., Ltd.

Claims (10)

[Claims] 1. A general formula of Moa Bib Fec Ad Be C
f Dg Ox (wherein Mo, Bi and Fe represent molybdenum, bismuth and iron, respectively, A represents nickel and / or cobalt, B is selected from the group consisting of manganese, zinc, calcium, magnesium, tin and lead. C, at least one element selected from the group consisting of phosphorus, boron, arsenic, tellurium, tungsten, antimony and silicon, and D is potassium, rubidium, cesium and thallium. Represents at least one element selected from the group consisting of
b ≦ 10, 0 <c ≦ 10, 0 <d ≦ 10, 0 ≦ e ≦ 1
0, 0 ≦ f ≦ 10, 0 <g ≦ 2, and x is a value determined by the oxidation state of each element), propylene in a fixed-bed multitubular reactor, In the method for producing the corresponding unsaturated aldehyde and unsaturated carboxylic acid by vapor-phase catalytic oxidation of isobutylene or tert-butanol with molecular oxygen, a complex oxide catalyst and a complex oxide catalyst which are unused in the reaction are used in the reaction. The method for producing unsaturated aldehydes and unsaturated carboxylic acids, characterized by reacting in the presence of a catalyst whose performance has deteriorated. 2. The production method according to claim 1, wherein molybdenum oxide is allowed to coexist with an unused composite oxide catalyst and a catalyst having deteriorated performance in the reaction. 3. After crushing a molded body of a catalyst having deteriorated performance,
The production method according to claim 1, wherein the compound oxide catalyst powder which has not been used in the reaction is mixed, molded and used. 4. After crushing a molded body of a catalyst having deteriorated performance,
The production method according to claim 1 or 2, wherein the compound oxide catalyst powder and the molybdenum oxide powder which are unused in the reaction are mixed and molded before use. 5. A molded product of a catalyst whose performance has deteriorated is used as a mixture with a molded product of a complex oxide catalyst which has not been used in the reaction.
The manufacturing method as described. 6. The method according to claim 1 or 2, wherein the molded product of the catalyst having deteriorated performance is used as a mixture with the molded product of the complex oxide catalyst and the molded product of molybdenum trioxide which are unused in the reaction. 7. A catalyst having deteriorated performance is treated at 400 to 700 ° C.
The manufacturing method according to claim 1, 2, 3, 4, 5 or 6, which is used by firing at. 8. The method according to claim 3 or 4, wherein the amount of the catalyst whose performance is deteriorated is 5 to 70% by weight of the complex oxide catalyst which is unused in the reaction. 9. The production method according to claim 5, wherein the amount of the catalyst whose performance has deteriorated is 6 to 80% by volume of the complex oxide catalyst which is unused in the reaction. 10. The production method according to claim 1, wherein a catalyst having deteriorated performance is present on the raw material gas inlet side of the reactor.