JPH09202741A - Production of methacrolein and methacrylic acid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain methacrolein and methacrylic acid in high yield by using a catalyst stably for a long time while preventing its deterioration as well as suppressing heat storage at a hot-spot during reaction. SOLUTION: The objective methacrolein and methacrylic acid are obtained by vapor phase catalytic of isobutylene by molecular oxygen or a molecular oxygen-contg. gas by use of stationary bed multitubular reactor in the presence of a multiple oxide catalyst of the formula Moa Wb Bic Fed Ae Bf Cg Dh Ei Ox (Mo is molebdenum; W is tungsten; Bi is bismuth; Fe is iron; A is nickel or cobalt; B is alkali metal or thallium; C is alkaliune earth metal; D is phosphorus, tellurium, etc.; E is silicon, aluminum, etc.; O is oxygen). It is preferable that the catalyst to be used for the reaction is of ring shape 10mm in outer diameter, with its length 0.5-2 times the outer diameter and the inner diameter of the penetrated hole in the longer direction 0.1-0.7 times the outer diameter.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing methacrolein and methacrylic acid by vapor-phase catalytic oxidation of isobutylene with molecular oxygen or a gas containing molecular oxygen.

[0002]

Many proposals have been made for catalysts used in the high temperature gas phase oxidation of isobutylene and / or t-butanol to produce methacrolein and methacrylic acid. These are mainly concerned with the selection of the components constituting the catalyst and the ratio thereof.

[0003] Since the above-mentioned oxidation reaction is a very exothermic reaction, the heat storage in the catalyst layer is large. Particularly, in a local abnormally high temperature zone called a hot spot, not only the yield decreases due to excessive oxidation reaction but also the heat load. The catalyst life is greatly affected by the deterioration of the catalyst. For this reason,
In industrial practice, heat storage in hot spots is a serious problem, especially when increasing the starting material concentration or space velocity to increase productivity (hereinafter, referred to as
In some cases, it may be referred to as "under high load reaction conditions."
At present, there are considerable restrictions on reaction conditions.

[0004] Therefore, suppressing the heat storage in the hot spot can be used for industrially producing methacrolein and methacrylic acid with a high yield, and also enables stable operation for a long period of time by suppressing deterioration of the catalyst. It is very important in doing so. Especially in the case of molybdenum-based catalyst,
Since the molybdenum component is easily sublimated, it is important to prevent heat storage at the hot spot.

Some proposals have been made in the past as a method for suppressing heat storage in a hot spot portion. For example,
Japanese Patent Publication No. 62-36740 proposes that the shape of the catalyst be ring-shaped. This publication discloses that in a molded catalyst usually used as a catalyst for oxidizing isobutylene or t-butanol, the shape of the catalyst is changed from a sphere or a column to a ring, thereby suppressing heat storage in a hot spot portion, thereby preventing excessive oxidation. It is stated that since the reaction can be suppressed, there is a great effect on improving the yield. However, although this method has the effect of reducing the heat load, it cannot be said that sufficiently satisfactory results can be obtained, especially under high load reaction conditions.

In addition, a method of providing a plurality of reaction zones by dividing a catalyst layer, filling the plurality of reaction zones with catalysts having different activities, and subjecting them to an oxidation reaction, for example, producing acrolein and acrylic acid from propylene. As a way to
It is known from JP-B-63-38331.

Japanese Unexamined Patent Publication (Kokai) No. 51-127003 discloses a method for producing an unsaturated aldehyde and an acid from propylene and isobutylene, which comprises a combination of a supported catalyst having essentially the same composition and a molded catalyst. However, in the examples, an example of producing acrolein and acrylic acid from propylene is shown, but the case of producing methacrolein and methacrylic acid from isobutylene is not specifically disclosed, and its effects are not described. Is difficult to evaluate.

In the reaction for producing methacrolein and methacrylic acid by subjecting isobutylene, t-butanol or methyl-t-butyl ether to gas phase catalytic oxidation,
All of these starting materials, unlike propylene, have a methyl group at the α-position, so that many side reactions such as parallel reaction and sequential reaction occur, and the number and amount of by-products are large. For example, the heat of reaction when producing methacrolein and methacrylic acid from isobutylene is greater than that when producing acrolein and acrylic acid from propylene, which promotes the heat storage of the catalyst layer and produces by-products by side reactions. It is promoting the increase of things. In addition, methacrolein is unstable compared to acrolein and easily causes so-called "post-reaction" such as autoxidation, which causes the yield to be further reduced.

As described above, the reaction of oxidizing isobutylene, t-butanol, or methyl-t-butyl ether to produce methacrolein and methacrylic acid is less than the reaction of oxidizing propylene to produce acrolein and acrylic acid. It is complicated and it is difficult to obtain the desired product in high yield. Therefore, it is not expected that a sufficient effect can be expected even if the knowledge obtained in the production of acrolein and acrylic acid is applied as it is to the production of methacrolein or methacrylic acid. Further studies have been needed to develop suitable catalysts or methods.

Further, in the catalyst described in Japanese Patent Publication No. 63-38331, the addition amount of the alkali metal component is very small compared to the other components, so that the addition effect is extremely large. For this reason, great care must be taken in the preparation of the catalyst, and it cannot always be said that the catalyst is appropriate in terms of controlling the catalytic activity.

[0011]

SUMMARY OF THE INVENTION One object of the present invention is to provide a method for producing methacrolein and methacrylic acid in a high yield by subjecting isobutylene to gas phase catalytic oxidation.

Another object of the present invention is to suppress the heat storage in a hot spot portion in a catalyst layer when isobutylene is subjected to gas-phase catalytic oxidation of isobutylene to produce methacrolein and methacrylic acid. It is an object of the present invention to provide a method for producing methacrolein and methacrylic acid, which is capable of stably using the catalyst for a long period of time by preventing the catalyst from deteriorating.

Another object of the present invention is to suppress the heat storage in a hot spot portion in a catalyst layer when producing isomethyrene by gas phase catalytic oxidation under high load reaction conditions to produce methacrolein and methacrylic acid. To provide a method for producing methacrolein and methacrylic acid, which aims to improve the yield of methacrylic acid and prevent catalyst deterioration so that the catalyst can be used stably for a long period of time and, consequently, significantly improve productivity. It is.

[0014]

Means for Solving the Problems The present inventors prepared a plurality of specific molybdenum-based catalysts having different activities, and provided a plurality of reaction zones by dividing a catalyst layer into two or more layers. It was found that the above object can be achieved by filling a plurality of reaction zones with a plurality of molybdenum-based catalysts having different activities from the raw material gas inlet to the outlet so that the activity becomes higher. Thus, the present invention has been completed.

That is, the present invention relates to a process for producing methacrolein and methacrylic acid by gas phase catalytic oxidation of isobutylene with molecular oxygen or a gas containing molecular oxygen using a fixed-bed multitubular reactor. as a catalyst, the following general formula (I) in _{Mo a W b Bi c Fe d} A e B f C g D h E i O x ( wherein, Mo is molybdenum, W is tungsten, Bi is bismuth, Fe is iron, A Is at least one element selected from nickel and cobalt; B is at least one element selected from alkali metals and thallium; C is at least one element selected from alkaline earth metals;
Is at least one element selected from phosphorus, tellurium, antimony, tin, cerium, lead, niobium, manganese, arsenic and zinc; E is at least one element selected from silicon, aluminum, titanium and zirconium; O is oxygen And a, b, c, d, e, f,
g, h, i, and x are Mo, W, Bi, Fe,
Represents the number of atoms of A, B, C, D, E and O, and a = 12
Then, b = 0.001 to 10, c = 0.1 to 1
0, d = 0.1-20, e = 2-20, f = 0-10,
g = 0 to 10, h = 0.001 to 4, i = 0.001 to
(30) x is a numerical value determined by the oxidation state of each element), and (b) the catalyst layer in each reaction tube is divided into two or more layers in the axial direction of the tube. (C) In the plurality of reaction zones, the activity of the catalyst prepared by changing the type and / or the amount of the elements constituting the groups A, D and E in the general formula (I) in the catalyst of the above (a) Packing a plurality of different catalysts and / or catalysts having different activities prepared by changing the amount of at least one element of W, Bi and Fe so that the activity becomes higher from the source gas inlet to the outlet. And a method for producing methacrolein and methacrylic acid.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The starting material used in the present invention is isobutylene, which is usually used as a mixed gas together with molecular oxygen, water vapor, an inert gas such as nitrogen or carbon dioxide gas.

The catalyst used in the present invention is a composite oxide represented by the above general formula (I). The method for preparing the catalyst and the raw materials are not particularly limited, and the catalyst can be prepared using the methods and raw materials generally used for preparing this type of catalyst.

In the present invention, a plurality of catalysts represented by the general formula (I) having different activities are prepared, and the plurality of catalysts are packed in a specific arrangement.

The catalysts having different activities can be easily prepared by changing the kinds and / or amounts of the elements constituting the groups A, D and E in the general formula (I). That is, the type and / or amount of at least one element selected from nickel, cobalt, phosphorus, tellurium, antimony, tin, cerium, lead, niobium, manganese, arsenic, zinc, silicon, aluminum, titanium and zirconium (however, In the general formula (I), e,
By varying (within the atomic ratio defined by h, i), catalysts with different activities are obtained.

At least one of W, Bi and Fe
By varying the amounts of the elements of the species, but within the atomic ratios defined by b, c and d in general formula (I) respectively, catalysts of different activity are obtained.

The catalyst used in the present invention is composed of the elemental components represented by the general formula (I), and the object of the present invention is achieved by combining these elemental components.

Specifically, the following embodiments can be shown. (1) By changing the amount of the W element in the general formula (I) in the divided reaction zone, a plurality of types of catalysts whose activity is controlled are prepared, and these catalysts are directed from the raw material gas inlet to the outlet. To make it more active.

(2) General formula (I) is added to the divided reaction zones.
A plurality of types of catalysts with controlled activities are prepared by changing the amount of the Bi element in, and these catalysts are filled so that the activity becomes higher from the source gas inlet portion toward the outlet portion.

(3) General formula (I) is added to the divided reaction zone.
In, the plural kinds of catalysts whose activities are controlled are prepared by changing the amount of Fe element, and these catalysts are filled so that the activity becomes higher from the raw material gas inlet portion toward the outlet portion.

(4) General formula (I) is added to the divided reaction zone.
A plurality of types of catalysts with controlled activity are prepared by changing the type and / or amount of at least one element selected from the group A elements in the above, and these catalysts are activated from the source gas inlet to the outlet. Fill so that it is higher.

(5) In the divided reaction zone, the general formula (I)
A plurality of types of catalysts with controlled activity are prepared by changing the type and / or amount of at least one element selected from the group D elements, and these catalysts are activated from the source gas inlet to the outlet. Fill so that it is higher.

(6) General formula (I) is added to the divided reaction zone.
A plurality of types of catalysts with controlled activity are prepared by changing the type and / or amount of at least one element selected from the group E elements in step 1, and these catalysts are activated from the raw material gas inlet to the outlet. Fill so that it is higher.

(7) In the divided reaction zones, the above (1) to
2 selected from catalysts with controlled activity described in (6)
One or more catalysts are packed so that the activity becomes higher from the raw material gas inlet portion toward the outlet portion.

The "activity" in the present invention means the conversion rate of the starting material.

The catalyst used in the present invention is a conventional molding method,
For example, the catalyst may be molded by an extrusion molding method or a tablet molding method. The composite oxide represented by the general formula (I) as a catalyst component may be formed on a carrier such as silicon carbide, alumina, zirconium oxide, and titanium oxide. May be supported on an inert carrier used as a carrier.

The plurality of catalysts packed in the reaction zone may have the same or different forms. For example, when the number of reaction zones is two, the supported catalyst is provided at the inlet of the raw material gas and the catalyst at the one outlet is provided. A molded catalyst may be placed in the part.

Regarding the shape of the catalyst used in the present invention,
There is no particular limitation, and any shape such as a sphere, a column, and a ring may be used. In particular, when a ring-shaped catalyst is used, heat accumulation in a hot spot portion is prevented, and various advantages such as a reduction in pressure loss in a catalyst layer can be obtained in addition to an improvement in yield and prevention of catalyst deterioration. In the above, a ring-shaped catalyst is preferably used. The outer diameter of the ring catalyst is 3
A ring-shaped catalyst having a length of 10 mm, a length of 0.5 to 2 times the outer diameter, and an inner diameter of the through hole in the length direction of 0.1 to 0.7 times the outer diameter is preferably used. .

The plurality of catalysts packed in the reaction zone may have the same or different shapes. For example, when the number of reaction zones is 2, a ring-shaped catalyst is provided at the inlet of the raw material gas and one catalyst is provided at the outlet. Better results are obtained by arranging the pellet-shaped catalyst in part.

In the present invention, the catalyst layer in each reaction tube is divided into two or more layers in the axial direction of the tube to provide a plurality of reaction zones,
In these reaction zones, a plurality of catalysts having different activities are arranged so that the activity increases sequentially from the inlet to the outlet of the raw material gas. That is, the catalyst with the lowest activity is located at the inlet, while the catalyst with the highest activity is located at the outlet. By arranging a plurality of catalysts having different activities in this manner, heat storage in the hot spot portion can be suppressed, and the target product can be obtained with a high selectivity.

The greater the number of divisions of the catalyst layer, the easier the control of the temperature distribution of the catalyst layer. However, industrially, it is possible to obtain the desired effect by using two or three layers. Further, the splitting ratio cannot be specified unconditionally because it depends on the composition, shape and the like of the catalyst of each layer, and may be appropriately selected so as to obtain the optimum activity and selectivity as a whole.

The vapor-phase catalytic oxidation reaction in the present invention may be a normal single flow method or a recycle method, and can be carried out under the conditions generally used for this type of reaction. For example, 1 to 10% by volume of isobutylene as a raw material gas, 3 to 20% by volume of molecular oxygen,
A mixed gas consisting of 0 to 60% by volume of water vapor and 20 to 80% by volume of an inert gas such as nitrogen or carbon dioxide is placed on the catalyst in a temperature range of 250 to 450 ° C., a normal pressure to 10 atm, and a space velocity. (SV) 300 to 5000 hr ^-1 (ST
Introduced in P).

According to the method of the present invention, it is particularly remarkable as compared with the conventional method under a high load reaction condition for the purpose of increasing productivity, for example, under a condition of a higher raw material concentration or a higher space velocity. Good results are obtained.

[0038]

According to the present invention, a plurality of specific molybdenum-based catalysts having different activities are packed into a plurality of divided catalyst layers so that the activity becomes higher from the inlet to the outlet of the raw material gas. Thereby, (a) methacrolein and methacrylic acid can be obtained in high yield, (b) heat storage in a hot spot portion can be effectively suppressed, (c)
Excessive oxidation reaction at the hot spot is prevented,
The desired methacrolein and methacrylic acid can be obtained in a high yield. (D) Deterioration of the catalyst due to heat load can be prevented, and the catalyst can be used stably for a long time. (E) High raw material concentration In addition, the desired methacrolein and methacrylic acid can be obtained in a high yield even under a high-load reaction condition such as a high space velocity, so that an effect such that productivity can be greatly increased can be obtained.

Furthermore, by using the ring-shaped catalyst, in addition to the above-mentioned effects, (f) the pressure loss in the catalyst layer can be reduced to reduce the power consumption.

Therefore, the method of the present invention is a very useful method for industrial production of methacrolein and methacrylic acid.

[0041]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples.

The conversion, the selectivity and the total single stream yield are defined by the following equations.

[0043]

[Equation 1]

[0044]

[Equation 2]

[0045]

(Equation 3)

Example 1 1456 g of cobalt nitrate and 202 g of ferric nitrate were dissolved in 1000 ml of water. 243 g of bismuth nitrate
Was dissolved in an aqueous nitric acid solution of 30 ml of concentrated nitric acid and 120 ml of water.

Separately, while stirring 3000 ml of water with heating, 1059 g of ammonium paramolybdate and 265 g of ammonium paratungstate were dissolved therein, and the above two separately prepared aqueous solutions were added dropwise to the resulting aqueous solutions.
Mixed. Next, 9.8 g of cesium nitrate is added to 30 ml of water.
Aqueous solution dissolved in, 79.8 g of tellurium dioxide, 20 more
203 g of silica sol having a weight% concentration was sequentially added and mixed.

The suspension thus obtained was heated and stirred, evaporated to dryness, and then formed into pellets having an outer diameter of 6 mm and a length of 6.6 mm, and calcined at 500 ° C. for 6 hours under air flow. Thus, a catalyst (1) was obtained. The composition of this catalyst (1) was Mo ₁₂ W ₂ Bi ₁ Fe ₁ Co ₁₀ Cs _0.1 Te _1.0 Si _1.35 in _terms of atomic ratio excluding oxygen.

A catalyst (2) was prepared in the same manner as the catalyst (1) except that the amount of tellurium dioxide was changed to 8.0 g in the method for preparing the catalyst (1). The composition of this catalyst (2) is
It was _{Mo 12 W 2 Bi 1 Fe 1} Co 10 Cs 0.1 Te 0.1 Si 1.35 at excluding oxygen atom ratio.

Regarding the activities of the catalysts (1) and (2), as is clear from the results of Comparative Examples 1 and 2 described later, the catalyst (2) has a higher activity than the catalyst (1).

The raw material gas inlet of a steel reaction tube having a diameter of 25.4 mm was filled with 750 ml of the above catalyst (1), while the raw material gas outlet was filled with 750 ml of the catalyst (2).

From the inlet of the reaction tube, a mixed gas having a composition of 6% by volume of isobutylene, 13.2% by volume of oxygen, 10% by volume of steam and 70.8% by volume of nitrogen was introduced, and the reaction temperature was 340 ° C. and the space velocity (SV). ) 1600 hr ^-1 (ST
P). Tables 1 and 2 show the catalyst filling method and results.

Comparative Example 1 A reaction was carried out in the same manner as in Example 1 except that the catalyst (2) was not used and only the catalyst (1) was charged in a 1500 ml reaction tube. Tables 1 and 2 show the catalyst filling method and results.

Comparative Example 2 A reaction was carried out in the same manner as in Example 1 except that the catalyst (1) was not used and 1500 ml of the catalyst (2) alone was charged. Tables 1 and 2 show the catalyst filling method and results.

Comparative Example 3 A catalyst (3) was prepared in the same manner as the catalyst (1) except that the amount of tellurium dioxide used was 43.9 g in the preparation of the catalyst (1) of Example 1.

The composition of this catalyst (3) was Mo ₁₂ W ₂ Bi ₁ Fe ₁ Co ₁₀ Cs _0.1 Te _0.55 Si _1.35 in _terms of atomic ratio excluding oxygen.

In Example 1, the catalyst (3) 150
The reaction was carried out in the same manner as in Example 1 except that only 0 ml was filled in the reaction tube. Tables 1 and 2 show the catalyst loading method and results.
Shown in

From the results shown in Table 2, the activity of catalyst (1) is very low, while the activity of catalyst (2) is high but the selectivity is low, while the total single-flow yield is low. It is understood that the total single-flow yield is high in the catalyst system of the present invention in which the catalysts (1) and (2) are combined, and the target methacrolein and methacrylic acid are obtained in high yield.
Further, comparing the catalyst (3) having an intermediate composition between the catalyst (1) and the catalyst (2) with the catalyst system of the present invention in which the catalysts (1) and (2) are combined, the catalyst (3) shows a total amount. Since the single-flow yield is low and the temperature difference (ΔT) between the reaction temperature and the catalyst layer maximum temperature is very large, it is considered that the catalyst is significantly deteriorated by the heat load. That is, it is understood that the effect of the present invention cannot be achieved even if a single catalyst (3) having a composition substantially the same as that of the catalyst system of the present invention is used alone. From these facts, it can be said that the catalyst system of the present invention is remarkably excellent in both single-flow yield and heat load.

Example 2 In Example 1, both catalysts (1) and (2) had an outer diameter of 6
The reaction was carried out in the same manner as in Example 1 except that the molded product was formed into a ring shape having a length of 6.6 mm, a length of 6.6 mm and an inner diameter of the through hole of 1 mm. Tables 1 and 2 show the catalyst filling method and results.

Comparative Example 4 In Comparative Example 1, the catalyst (1) had an outer diameter of 6 mm and a length of 6.
The reaction was carried out in the same manner as in Comparative Example 1, except that a ring was formed having a diameter of 6 mm and an inner diameter of the through-hole of 1 mm. Tables 1 and 2 show the catalyst filling method and results.

Comparative Example 5 In Comparative Example 2, the catalyst (2) had an outer diameter of 6 mm and a length of 6.
The reaction was carried out in the same manner as in Comparative Example 2 except that a ring was formed having a diameter of 6 mm and an inner diameter of the through-hole of 1 mm. Tables 1 and 2 show the catalyst filling method and results.

Comparative Example 6 In Comparative Example 3, the catalyst (3) had an outer diameter of 6 mm and a length of 6.
The reaction was carried out in the same manner as in Comparative Example 3, except that the ring was molded into a ring having a diameter of 6 mm and an inner diameter of the through-hole of 1 mm. Tables 1 and 2 show the catalyst filling method and results.

In Example 2 and Comparative Examples 4 to 6, the catalysts (1) to (3) were changed from pellets to rings. From the results in Table 2, catalysts (1) to (3)
In any of the cases, when the shape is changed to a ring shape, an increase in yield and a decrease in ΔT are observed. However, the catalysts (1), (3) (2)
The catalyst system of the present invention in which
It is understood that both are excellent.

Example 3 In the same manner as in Example 1, except that the catalyst (1) was molded into a ring shape having an outer diameter of 6.0 mm, a length of 6.6 mm and a through hole inner diameter of 1.0 mm. The reaction was carried out. Tables 1 and 2 show the catalyst filling method and results.

By changing the shape of the catalyst charged at the inlet of the reaction tube from the pellet shape to the ring shape, the single-flow yield is further improved, and ΔT is also lowered, which is superior to the combination of the pellet-shaped catalysts. It turned out to be obtained.

Example 4 A reaction was carried out in the same manner as in Example 1 except that the reaction was carried out for a long time up to 4000 hours.
Tables 1 and 2 show the catalyst filling method and results.

From the results shown in Table 2, the decrease in activity is very low even after 4000 hours of reaction, and the decrease in yield is almost negligible. In the case of the catalyst system of the present invention, a very stable continuous operation for a long period of time is carried out. It is understood that it can be done.

Comparative Example 7 The reaction was carried out in the same manner as in Comparative Example 3 except that the reaction time was changed to 4000 hours. Tables 1 and 2 show the catalyst filling method and results.

From the results of Table 2, as compared with the case of Example 4,
It is understood that both the activity and the yield are greatly reduced, and there is a problem in the stability of the catalyst.

Example 5 A reaction was carried out in the same manner as in Example 2 except that the reaction temperature was changed to 360 ° C. and the space velocity was changed to 3000 hr ⁻¹ (STP). Tables 1 and 2 show the catalyst filling method and results.

Comparative Example 8 The reaction was performed in the same manner as in Comparative Example 4 except that the reaction time was changed to 360 ° C. and the space velocity was changed to 3000 hr ⁻¹ (STP). Tables 1 and 2 show the catalyst filling method and results.

Comparative Example 9 A reaction was carried out in the same manner as in Comparative Example 6 except that the reaction temperature was changed to 360 ° C. and the space velocity was changed to 3000 hr ⁻¹ (STP). Tables 1 and 2 show the catalyst filling method and results.

From the results of Example 5 and Comparative Examples 8 to 9,
It is understood that even when the space velocity is increased, the difference in activity and yield of the catalyst system of the present invention obtained by combining the catalysts (1) and (2) with respect to the catalyst (1) or (3) appears as it is. .

Example 6 A reaction was carried out in the same manner as in Example 2 except that the ratios of isobutylene and nitrogen in the raw material gas were changed to 7% by volume and 69.8% by volume, respectively. Tables 1 and 2 show the catalyst filling method and results.

Comparative Example 10 A reaction was carried out in the same manner as in Comparative Example 4 except that the ratios of isobutylene and nitrogen in the raw material gas were changed to 7% by volume and 69.8% by volume, respectively. Tables 1 and 2 show the catalyst filling method and results.

Comparative Example 11 The reaction was performed in the same manner as in Comparative Example 6 except that the ratios of isobutylene and nitrogen in the raw material gas were changed to 7% by volume and 69.8% by volume, respectively. Tables 1 and 2 show the catalyst filling method and results.

From the results of Example 6 and Comparative Examples 10 to 11, even when the isobutylene concentration was increased, the catalyst (1),
It is understood that the difference in yield and ΔT of the catalyst system of the present invention obtained by combining (2) with the catalyst (1) or the catalyst (3) appears as it is. In particular, the catalyst layer
Regarding the increase in T, since the catalyst system of the present invention is considerably smaller than the single catalyst, arranging the catalysts as in the present invention is effective in minimizing catalyst deterioration due to heat load. Conceivable.

Example 7 In Example 1, nickel nitrate was used instead of cobalt nitrate, and the amount of bismuth nitrate used was changed.
In the same manner as in Example 1 except that rubidium nitrate and magnesium nitrate were used instead of cesium nitrate, stannic oxide was added instead of tellurium dioxide, and aluminum nitrate was used in addition to silica sol. A suspension was prepared, and a ring-shaped catalyst (4) was prepared in the same manner as in Example 2 below.

The composition of this catalyst (4) is Mo ₁₂ W ₂ Bi _1.2 Fe ₁ Ni ₇ Rb _0.1 Mg _0.5 Sn _1.0 A in terms of atomic ratio excluding oxygen.
1 _1.0 Si _1.35 .

A suspension was prepared in the same manner as in the above catalyst (4) except that the amounts of bismuth nitrate, stannic oxide and silica sol used were changed, and pelletized catalyst (5 ) Was prepared.

The composition of this catalyst (5) was Mo ₁₂ W ₂ Bi _2.0 Fe ₁ Ni ₇ Rb _0.1 Mg _0.5 Sn _0.1 A in terms of atomic ratio excluding oxygen.
1 _1.0 Si _0.5 .

The gas inlet side of a steel reaction tube having a diameter of 25.4 mm was filled with 750 ml of the catalyst (4), while the gas outlet side was filled with 750 ml of the catalyst (5). Hereinafter, Example 1
The reaction was carried out in the same manner as in. The catalyst loading method and results are shown in Tables 3 and 4.

Example 8 In Example 1, changing the amount of cobalt nitrate used, using thallium nitrate, barium nitrate and cerium nitrate in addition to cesium nitrate, and not using tellurium dioxide. Further, a suspension was prepared in the same manner as in Example 1 except that aluminum nitrate was used instead of silica sol, and a ring-shaped catalyst (6) was obtained in the same manner as in Example 2 below.

The composition of this catalyst (6) is Mo ₁₂ W ₂ Bi ₁ Fe ₁ Co ₆ Cs _0.1 Tl _0.2 Ba _0.1 Ce in terms of atomic ratio excluding oxygen.
It was _0.2 Al _2.0 .

A ring-shaped catalyst (7) was prepared in the same manner as the catalyst (6) except that the amounts of ferric nitrate, cerium nitrate and aluminum nitrate were changed. The composition of this catalyst (7) is Mo ₁₂ W ₂ Bi ₁ Fe _1.4 Co ₆ Cs _0.1 Tl _0.2 Ba _0.1 C in terms of atomic ratio excluding oxygen.
It was e ₁ Al _1.0 .

The gas inlet of a steel reaction tube having a diameter of 25.4 mm was filled with 750 ml of the catalyst (6), and then the gas outlet was filled with 750 ml of the catalyst (7). Thereafter, the reaction was carried out in the same manner as in Example 1. The catalyst loading method and results are shown in Tables 3 and 4.

Example 9 In Example 1, the amount of cobalt nitrate used was changed, potassium nitrate, lithium nitrate and beryllium nitrate were used instead of cesium nitrate, tellurium dioxide,
A suspension was prepared in the same manner as in Example 1 except that titanium dioxide was used instead of silica sol, and manganese nitrate was finally used.

1600 ml of a spherical carrier made of α-alumina having a diameter of 6 mm was immersed in this suspension, and then heated to a predetermined temperature with stirring to support the catalyst composition. The obtained supported catalyst was passed through air at 500 ° C.
The mixture was calcined for 6 hours to obtain a catalyst (8). The composition of the supported oxide of this catalyst (8) is Mo ₁₂ W ₂ Bi ₁ Fe ₁ Co ₃ K _0.2 Li _1.5 Be _0.2 Mn _2.0 in terms of atomic ratio excluding oxygen.
It was Ti _3.0 . The amount of oxide supported was 20 g per 100 ml of the carrier.

A suspension was prepared in the same manner as catalyst (8) except that the amounts of cobalt nitrate and titanium dioxide were changed, and phosphoric acid was used instead of manganese nitrate, and then Example 1 was used.
A pellet-shaped catalyst (9) was obtained in the same manner as in.

The composition of this catalyst (9) was Mo ₁₂ W ₂ Bi ₁ Fe ₁ Co ₆ K _0.2 Li _1.5 Be _0.2 P _0.2 T in terms of atomic ratio excluding oxygen.
i was _1.0 .

900 ml of the catalyst (8) was charged to the gas inlet side of a steel reactor having a diameter of 25.4 mm, while 600 ml of the catalyst (9) was charged to the gas outlet side. Then, the reaction was carried out in the same manner as in Example 1, except that the reaction temperature was 350 ° C. The catalyst loading method and results are shown in Tables 3 and 4.

Example 10 In Example 1, ammonium paratungstate,
Examples except changing the amounts of ferric nitrate and cobalt nitrate, using calcium nitrate in addition to cesium nitrate, then adding zinc nitrate, and further using tellurium dioxide, zirconium nitrate instead of silcasol. A suspension was prepared in the same manner as 1. 1600 ml of a ring-shaped carrier made of silica-alumina having an outer diameter of 6 mm, a length of 5 mm and a through hole inner diameter of 3 mm was weighed and used to carry the supported catalyst (1) in the same manner as the catalyst (8) of Example 11.
0) was prepared.

The composition of the supported oxide of this catalyst (10) is
Mo ₁₂ W ₁ Bi ₁ Fe _1.2 Co ₅ Cs _0.1 Ca _0.3 Zn _1.0 Z in atomic ratio excluding oxygen
It was r _2.0 . The amount of oxide supported was 24 g per 100 ml of the carrier.

In addition, ammonium paratungstate,
A suspension was prepared in the same manner as the catalyst (10) except that the amounts of bismuth nitrate, zinc nitrate and zirconium nitrate used were changed. Using this suspension, a ring-shaped catalyst (11) was obtained in the same manner as in Example 2.

The composition of this catalyst (11) was Mo ₁₂ W ₂ Bi _1.4 Fe _1.2 Co ₅ Cs _0.1 Ca _0.3 Zn _{1.2 in} terms of atomic ratio excluding oxygen.
It was Zr _1.7 .

1000 ml of the catalyst (10) was filled in the gas inlet of a steel reaction tube having a diameter of 25.4 mm, while 500 ml of the catalyst (11) was filled in the gas outlet side. The reaction was performed in the same manner as in Example 1 except that the reaction temperature was 350 ° C. The catalyst loading method and results are shown in Tables 3 and 4.

Example 11 In Example 1, varying the amounts of ammonium paratungstate and cobalt nitrate, using sodium nitrate in addition to cesium nitrate, followed by addition of lead nitrate and tellurium dioxide, and under air flow. A catalyst (12) was prepared in the same manner as in Example 1 except that the calcination was performed at 530 ° C. for 6 hours.
Was prepared.

The composition of this catalyst (12) is Mo ₁₂ W _1.5 Bi ₁ Fe ₁ Co ₇ Cs _0.1 Na _1.0 Pb _0.1 T in terms of atomic ratio excluding oxygen.
e _1.0 Si _1.35 .

Varying the amounts of lead nitrate and tellurium dioxide,
A catalyst (13) was prepared in the same manner as the above catalyst (12) except that antimony trioxide was used and the composition was calcined at 450 ° C.
Was prepared.

The composition of this catalyst (13) was Mo ₁₂ W _1.5 Bi ₁ Fe ₁ Co ₇ Cs _0.1 Na _1.0 Pb _1.0 T in terms of atomic ratio excluding oxygen.
e _0.2 Sb _0.1 Si _1.35 .

A steel reaction tube having a diameter of 25.4 mm was charged with 750 ml of the catalyst (12) on the inlet side, and 750 ml of the catalyst (13) on the outlet side. Thereafter, the reaction was carried out in the same manner as in Example 1. The catalyst loading method and results are shown in Tables 3 and 4.

Example 12 In Example 1, nickel nitrate was used instead of cobalt nitrate, rubidium nitrate and strontium nitrate were used instead of cesium nitrate, the amount of tellurium dioxide was changed, and niobium pentoxide was used. A suspension was prepared in the same manner as in Example 1 except for the above. After this suspension was evaporated to dryness, it was molded into a ring shape with an outer diameter of 6 mm, a length of 6.6 mm, and a through hole inner diameter of 2.0 mm, and was allowed to flow under air flow at
A catalyst (14) was prepared by calcining at 0 ° C. for 6 hours.

The composition of this catalyst (14) was Mo ₁₂ W ₂ Bi ₁ Fe ₁ Ni ₃ Rb _0.8 Sr _0.1 Te _0.8 Nb in terms of atomic ratio excluding oxygen.
It was _0.2 Si _1.35 .

In addition, ammonium paratungstate,
A ring-shaped catalyst (15) was obtained in the same manner as the catalyst (14) except that the amounts of ferric nitrate, nickel nitrate, tellurium dioxide, and niobium pentoxide were changed, and the firing temperature was 470 ° C. It was

The composition of this catalyst (15) was Mo ₁₂ W _2.4 Bi ₁ Fe _1.2 Ni ₇ Rb _0.8 Sr _0.1 Te _{0.1 in} terms of atomic ratio excluding oxygen.
It was Nb _0.1 Si _1.35 .

Then, the reaction was carried out in the same manner as in Example 1. The catalyst loading method and results are shown in Tables 3 and 4.

[0107]

[Table 1]

[0108]

[Table 2]

[0109]

[Table 3]

[0110]

[Table 4]

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication C07C 45/35 9049-4H C07C 45/35 47/22 9049-4H 47/22 A 9049-4H G 57/04 2115-4H 57/04 57/05 2115-4H 57/05 // C07B 61/00 300 C07B 61/00 300 (72) Inventor Ikuo Kurimoto 1st at 992 Nishikioki, Akihama, Aboshi-ku, Hyogo Prefecture Nippon Catalyst (72) Inventor Yukio Aoki 1 of 992 Nishikioki, Okihama, Aboshi-ku, Himeji City, Hyogo Prefecture Japan Catalysis Laboratory Co., Ltd.

Claims (3)

[Claims] 1. A method for producing methacrolein and methacrylic acid by vapor-phase catalytic oxidation of isobutylene with molecular oxygen or a gas containing molecular oxygen using a fixed-bed multitubular reactor, wherein (a) as a catalyst, following general formula (I) in _{Mo a W b Bi c Fe d} A e B f C g D h E i O x ( wherein, Mo is molybdenum, W is tungsten, Bi is bismuth, Fe is iron, A is nickel and At least one element selected from cobalt, B is at least one element selected from alkali metals and thallium, C is at least one element selected from alkaline earth metals,
D is phosphorus, tellurium, antimony, tin, cerium, lead,
At least one element selected from niobium, manganese, arsenic and zinc, E is at least one element selected from silicon, aluminum, titanium and zirconium, O is oxygen, and a, b, c, d, e , F,
g, h, i and x are Mo, W, Bi and F, respectively.
represents the number of atoms of e, A, B, C, D, E and O, and a =
When set to 12, b = 0.001 to 10 and c = 0.1
10, d = 0.1-20, e = 2-20, f = 0-1
0, g = 0 to 10, h = 0.001 to 4, i = 0.00
1 to 30, x = a numerical value determined by the oxidation state of each element) is used, and (b) the catalyst layer in each reaction tube is divided into two or more layers in the axial direction of the tube. In a plurality of reaction zones provided, (c) in the catalyst of (a) above,
Of the catalysts having different activities prepared by changing the types and / or amounts of the elements constituting the groups A, D and E in the general formula (I), and / or at least one element of W, Bi and Fe A method for producing methacrolein and methacrylic acid, characterized in that a plurality of catalysts having different activities prepared in different amounts are filled so that the activity becomes higher from an inlet portion of a raw material gas toward an outlet portion thereof. 2. The method according to claim 1, wherein the number of reaction zones is two or three.
The method for producing methacrolein and methacrylic acid according to the above. 3. The catalyst has an outer diameter of 3 to 10 mm, a length of 0.5 to 2 times the outer diameter, and an inner diameter of the through hole in the length direction of 0.1 to 0.7 times the outer diameter. The method for producing methacrolein and methacrylic acid according to claim 1 or 2, which is a ring catalyst.