JPH10216523A - Catalyst for producing metacrolein and production of metacrolein - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain high reduction resistance and heat resistance and prolong the life of a catalyst, which is to be used at the time of producing metacrolein by carrying out gas-phase contact oxidation of isobutylene by molecular oxygen- containing gas, by producing the catalyst from a catalyst composition of a formula. SOLUTION: A compound of the formula Mo12 Bia Ab Kc Fed Cee Bf Cg Oh is used as the catalyst composition to be used for producing metacrolein. In the formula, Mo is molybdenum, Bi is bismuth, K is potassium, Fe is iron, Ce is cerium, A stands for praseodymium, neodymium, lanthanum, etc., B stands for solely cobalt, nickel, or a mixture containing two or more elements selected from cobalt, nickel, and magnesium at a ratio satisfying the following; 0 <=magnesium/(cobalt + nickel + magnesium)<=0.5, and C stands for rubidium and cesium.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a gas phase catalytic oxidation of at least one selected from the group consisting of isobutylene and t-butyl alcohol using a molecular oxygen-containing gas in the presence of an oxidation catalyst composition. The present invention relates to a catalyst having excellent reduction resistance and heat resistance, and having a long catalyst life, and a method for producing methachlorene using the catalyst.

[0002]

2. Description of the Related Art At least one selected from isobutylene and t-butyl alcohol is subjected to a gas phase catalytic oxidation reaction,
Numerous proposals have been made for catalysts used in producing methachlorene. These are mainly concerned with the selection of the components constituting the catalyst and the ratio thereof. For example, JP-A-48-17253 and JP-A-5-17
JP-A-1-34107, JP-A-60-28824, JP-A-60-163830, JP-A-63-1
22641, JP-A-2-227140 and the like.

A conventional method using a rare earth element as a method for enhancing the catalytic performance is disclosed in, for example, Japanese Patent Application Laid-Open No. 51-34107.
Japanese Patent Application Laid-Open Publication No. H11-177, pp. 147-64 describes an example of a Ce-added catalyst obtained by drying in a paste state and then calcining, but it cannot be said that the selectivity of methachlorene is sufficient. JP-A-4-4
No. 1454 describes that a catalyst obtained by mechanically mixing a composite oxide containing a rare earth element and Mo into a catalyst composition and then calcining the catalyst is excellent in activity and selectivity for methachlorene. However, in addition to the catalyst composition, preparation of the above-mentioned composite oxide is separately required, and when preparing a catalyst on an industrial scale, there is a disadvantage that a problem of uneven mixing in a mechanical mixing operation is likely to occur. .

[0004] Further, since the present metachlorene synthesis reaction is an oxidation reaction accompanied by a large amount of heat generation, not only the reaction performance is deteriorated due to the heat storage in the catalyst layer, but also the deterioration of the catalyst due to heat load is caused in industrial practice. It is a big problem.
As a measure to reduce the heat load of the catalyst,
Japanese Patent No. 6740 proposes that the shape of the catalyst be made ring-shaped to reduce the heat storage phenomenon.
JP-A-6440 and JP-A-3-200733 disclose that a catalyst layer is divided into a plurality of reaction zones, and the plurality of reaction zones are filled with catalysts having different activities to obtain a temperature distribution in which heat storage hardly occurs. It has been proposed to adjust. Japanese Patent Application Laid-Open No. 4-41453 discloses that a catalyst contains 5 to 15 silica particles.
It has been proposed to improve the stability of the catalyst by including it by weight. Although heat storage measures have been taken by the shape of the catalyst, the method of filling the catalyst, and the addition of silica, further improvement in the thermal stability of the catalyst is desired from the viewpoint of catalyst life.

In the above-mentioned oxidation reaction, the oxidation reaction and the reduction reaction are always repeated on the catalyst, and the catalytic function is maintained by the balance of the oxidation-reduction reaction. However, if the amount of oxygen relative to the raw material is significantly reduced for some reason, for example, due to an operation error or a local runaway reaction, the catalyst is reduced, the crystal phase of the chemical species constituting the catalyst is changed, and catalyst deterioration is accelerated. I will. JP 61
JP-A-33234 proposes means for restoring the catalyst function by oxidizing the deteriorated catalyst, but it is desired to develop a catalyst having a higher resistance to reduction from the viewpoint of the life of the catalyst.

[0006] The present inventors have disclosed in WO95 / 35273 that a high catalyst selectivity, excellent heat resistance and reduction resistance, low solubility of W and Sb raw materials are unnecessary, a simple catalyst production method is possible, and Mo, Mo, as a catalyst that does not cause environmental problems at the time of preparing the catalyst or recovering the catalyst component
We proposed a catalyst focusing on Bi, Ce, K, Fe, Co, Mg, Cs, and Rb. However, when industrially producing methacrolein, there has been a strong demand for the development of a catalyst having excellent reduction resistance and heat resistance and a long catalyst life.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide at least one selected from the group consisting of isobutylene and t-butyl alcohol in the presence of an oxidation catalyst composition using a gaseous oxygen-containing gas. An object of the present invention is to provide a catalyst used for producing methacrolein by catalytic oxidation, which is excellent in reduction resistance and heat resistance, has a long catalyst life, and a method for producing methacrolein using the catalyst.

[0008]

Means for Solving the Problems The inventors of the present invention have prepared a gas phase using at least one selected from the group consisting of isobutylene and t-butyl alcohol using a molecular oxygen-containing gas in the presence of an oxidation catalyst composition. Regarding the catalyst used when producing methacrolein by catalytic oxidation, Mo, Bi, a lanthanoid group element and Y,
K, Fe, Ce, Co, Ni, Mg, Rb, and Cs are selected, and the content of the lanthanoid group element and Y, the catalyst composition,
The adjustment method was studied diligently. As a result, surprisingly, by adding at least one element consisting of a lanthanoid group element and Y to the catalyst component, the catalyst has excellent reduction resistance and heat resistance, has a long catalyst life, We have discovered a catalyst that can produce methacrolein stably. The present invention has been completed based on this finding.

That is, the present invention provides an oxidizing method for producing methacrolein by reacting at least one selected from the group consisting of isobutylene and t-butyl alcohol with a molecular oxygen-containing gas represented by the following formula (I): The present invention relates to a catalyst composition and a method for producing methacrolein using the catalyst. During _{Mo 12 Bi a A b K c} Fe d Ce e B f C g O h (I) ( wherein, Mo is molybdenum, Bi is bismuth, K is potassium, Fe is iron, Ce is cerium, A is praseodymium , Neodymium, lanthanum, samarium, europium, gadolinium, terbium, dysprosium, yttrium or a mixture thereof, and B is cobalt alone, nickel alone, or a mixture of two or more selected from the group consisting of cobalt, nickel and magnesium. hand,
The ratio of magnesium to cobalt and nickel in the mixture is 0 ≦ magnesium / (cobalt + nickel + magnesium) ≦ 0.5, and C is rubidium, cesium or a mixture thereof. a, b, c, d,
e, f, g, and h are respectively bismuth, A, potassium, iron, cerium, B, C with respect to 12 molybdenum atoms.
And the atomic ratio of oxygen, 0 <a ≦ 8, 0 <b ≦ 8, 0 <c ≦ 1.2, 0 <d ≦ 2.5, 0 ≦ e ≦ 2, 1.0 ≦ f ≦ 12, 0 <g ≦ 2.0 h is the number of atoms necessary to satisfy the valence conditions of the other elements present, and a, b, c, d and e are represented by the following formula: 0.05 ≦ (b + e) The following condition is satisfied: /(a+b+c+e)≦0.70<c/(a+b+c+e)≦0.40<d/(a+b+d+e)≦0.9 Bismuth (Bi) is an essential element in synthesizing methacrolein, and in order for the catalyst composition of the present invention to exhibit its intended function, the atomic ratio of Bi to molybdenum (Mo) 12 atoms (a ) Must satisfy the condition 0 <a ≦ 8.

[0010] Praseodymium (Pr), neodymium (N
d), lanthanum (La), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), and yttrium (Y) are catalyst lifetimes at the time of low oxygen partial pressure reaction. Reduction resistance,
Molybdenum (M) is an essential element for imparting heat resistance.
o) The atomic ratio (b) of group A to 12 atoms is 0 <b
It is necessary to satisfy the condition of ≦ 8.

Further, Pr, Nd, La, Sm, Eu,
In order to maintain a high selectivity and significantly improve the heat resistance and reduction resistance of the catalyst by adding Gd, Tb, Dy, and Y, Pr, Nd, La, Sm, Eu, Gd, Tb,
It is necessary that the relative amounts of Dy, Y and Bi, K, Ce are within a specific range. That is, in the catalyst composition represented by the formula (I), a, b, c, and e satisfy the formula 0.05 ≦ (b +
e) / (a + b + c + e) ≦ 0.7, and it is necessary to satisfy the following condition: 0.1 ≦ (b +
It is preferable to satisfy the condition represented by e) / (a + b + c + e) ≦ 0.5.

Potassium (K) is Pr, Nd, La, S
It is indispensable to enhance the effect of adding m, Eu, Gd, Tb, Dy, and Y, and also to improve the selectivity of methacrolein, and the atomic ratio (c) of K to Mo12 atoms is 0. It is necessary to satisfy the condition of <c ≦ 1.2. If the amount of K is large and c> 1.2, even if the amount of elements other than K is adjusted or the sintering temperature is adjusted, sufficient desired catalytic activity cannot be exhibited.

Further, regarding K, K and Bi, Pr,
Nd, La, Sm, Eu, Gd, Tb, Dy, Y and Ce
Is important, and a, b, c, and e satisfy the formula 0 <c /
It is necessary to satisfy the condition represented by (a + b + c + e) ≦ 0.4, and further, the expression 0.02 ≦ c / (a + b + c +)
e) It is preferable to satisfy the condition represented by ≦ 0.2. Although iron is used, when the Fe content increases, by-products such as CO and CO ₂ tend to increase, and the selectivity for methacrolein decreases. The atomic ratio (d) of Fe to Mo12 atoms must satisfy the condition of 0 <d ≦ 2.5.

Further, regarding Fe, Fe and Bi, P
r, Nd, La, Sm, Eu, Gd, Tb, Dy, Y,
The relative amounts of K and Ce are important, and it is necessary that a, b, d, and e satisfy the condition represented by the formula 0 <d / (a + b + d + e) ≦ 0.9. 1 <d / (a +
It is preferable to satisfy the condition represented by (b + d + e) ≦ 0.5 in order to obtain good catalytic performance. In particular, Fe is 0 <d ≦ 2.5 and 0 <d / (a + b +
It is necessary to satisfy the two conditions of d + e) ≦ 0.9 in order to exhibit high selectivity to methacrolein.

Bi, Pr, Nd, La, Sm, Eu, G
It is not clear why the effects desired in the present invention can be obtained by satisfying the above-mentioned conditions for the quantitative relations of d, Tb, Dy, Y, K, and Ce.
i, Pr, Nd, La, Sm, Eu, Gd, Tb, D
It is considered that the molybdenum compounds of y, Y, K and Ce are individually dissolved in each other in a specific atomic ratio region and a sintering temperature region, and exhibit advantageous characteristics desired in the present invention.

The atomic ratio (e) of Ce needs to satisfy the condition of 0 ≦ e ≦ 2. Ce is an essential element for extracting excellent performance with respect to heat resistance, reduction resistance and catalyst life. Nonetheless, by including Ce in this range, the selectivity of methacrolein is enhanced. In the catalyst composition represented by the formula (I), Co and Ni are indispensable as B in the formula (I) in order to increase the catalytic activity without lowering methacrolein selectivity.
The atomic ratio (f) of Co and Ni to the atom is 1.0 ≦ f
It is necessary to satisfy the condition of ≦ 12. Further, when Mg is contained as the B component, the amount of Mg with respect to Co and Ni is 0%.
It must be in the range of ≦ Mg / (Co + Ni + Mg) ≦ 0.5. If the amount of Mg is out of this range, the heat resistance of the catalyst, the selectivity of methacrolein, and the catalytic activity will decrease.

In order to further increase the selectivity of methacrolein, it is essential to add rubidium (Rb), cesium (Cs) or a mixture thereof to the catalyst component as C in the above formula (I). is there. It is necessary that the atomic ratio (g) of C to Mo12 atoms satisfies the condition of 0 <g ≦ 2.0, and it is preferable that the condition of 0.1 ≦ g ≦ 1.0 be satisfied. When g> 2.0, Rb,
Even if the amount of elements other than Cs is adjusted or the firing temperature is adjusted, sufficient catalytic activity cannot be exhibited.

The catalyst composition of the present invention can be obtained by a known method, for example, a first step of preparing a raw material slurry, a second step of spray-drying the raw material slurry, and calcining the dried particles obtained in the second step. And a method including a third step. Next, the first to third catalyst compositions of the present invention
A preferred embodiment of the manufacturing method comprising the steps will be described.

In the first step, a raw material slurry is obtained by preparing a raw material for the catalyst. Molybdenum, bismuth, praseodymium, neodymium, lanthanum, samarium, europium,
Gadolinium, terbium, dysprosium, yttrium, potassium, iron, cerium, cobalt, magnesium, nickel, rubidium and cesium as the elemental sources include ammonium salts, nitrates soluble in water or nitric acid,
Hydrochloride, organic acid salt and the like can be mentioned. In particular, as a molybdenum source, an ammonium salt is used as an elemental source of bismuth, praseodymium, neodymium, lanthanum, samarium, europium, gadolinium, terbium, dysprosium, yttrium, potassium, iron, cerium, cobalt, magnesium, nickel, rubidium and cesium. Each nitrate is preferred.

For example, the raw material slurry can be prepared by mixing a solution in which an ammonium salt of molybdenum is dissolved in warm water and a solution in which another element is dissolved in water or an aqueous nitric acid solution as a nitrate. In the second step, the first
The raw material slurry obtained in the step is spray-dried to obtain pseudo spherical particles. The atomization of the raw material slurry can be performed by a method such as a centrifugal method, a two-fluid nozzle method, and a high-pressure nozzle method which are usually carried out industrially.As a drying heat source, air heated by steam, an electric heater, or the like is used. Preferably, it is used. At this time, it is desirable that the temperature at the dryer inlet of the spray dryer is in the range of 150 to 400 ° C. By using the dry powder as a raw material, it is possible to prepare an extruded catalyst, more preferably, a tableting catalyst having less variation.

In the third step, the desired particles are obtained by calcining the dried particles obtained in the second step. The calcination of the dried particles is performed in a temperature range of 180 to 400 ° C. for 1 to 24 hours.
Pre-baking is performed for about an hour, and tableting is performed into an appropriate shape if necessary, and then performed at a temperature of 350 to 600 ° C. for 1 to 24 hours.
Perform firing for a time. The firing can be performed using a firing furnace such as a rotary furnace, a tunnel furnace, and a muffle furnace.

From the viewpoint of improving the selectivity, it is desirable that the catalyst composition does not contain silica or contains silica as little as possible. However, when silica is used for the purpose of increasing the surface area of the catalyst composition and increasing the activity, silica sol, silica gel, or a silicate such as potassium silicate or sodium silicate can be used as the raw material. In this case, the Si component is desirably 3 atoms or less, preferably 1 atom or less, more preferably 0.1 atom or less based on Mo12 atoms.

In the method of the present invention, the gas phase catalytic oxidation method is characterized in that a molecular oxygen concentration is increased in the presence of an oxide catalyst composition with respect to 1 to 10% by volume of isobutylene, t-butyl alcohol or a mixed gas of both. A raw material gas comprising a mixed gas to which a molecular oxygen-containing gas and a diluent gas are added so as to have a volume of 1 to 20% by volume is added to the tableting catalyst layer in a fixed bed reactor in a temperature range of 250 to 480 ° C. Under a pressure of normal pressure to 5 atm, space velocity 400 to 4000 / hr [Normal t
emperature pressure (NTP) conditions].

Examples of the molecular oxygen-containing gas include pure oxygen gas and gas containing oxygen such as air.
Examples of the dilution gas include nitrogen, carbon dioxide,
Examples include steam and a mixed gas thereof. Regarding the mixing ratio of the molecular oxygen-containing gas and the diluent gas in the above-mentioned mixed gas, the condition of 0.01 <molecular oxygen / (molecular oxygen-containing gas + diluent gas) <0.3 by volume ratio should be satisfied. Is preferred. Further, the concentration of molecular oxygen in the source gas is preferably 1 to 20% by volume.

The water vapor in the raw material gas is necessary in order to prevent coking to the catalyst, but it is necessary to reduce the water vapor concentration in the diluent gas as much as possible in order to suppress by-products of carboxylic acids such as methacrylic acid and acetic acid. Is preferred. The water vapor in the source gas is usually used in the range of 0 to 30% by volume.

[0026]

Now, the present invention will be described in further detail with reference to Examples and Comparative Examples. The number of oxygen atoms in the catalyst composition is determined by the valence conditions of other elements, and in Examples and Comparative Examples, oxygen atoms are omitted in the formulas representing the composition of the catalyst composition. .

In Examples and Comparative Examples, the conversion, selectivity, and yield used to express the reaction results are defined by the following equations.

[0028]

(Equation 1)

[0029]

(Equation 2)

[0030]

(Equation 3)

[0031]

Mo as Example 1 composition atomic ratio based on the Mo12 atoms _{12 Bi 1.65 Pr 0.2 Nd 0.2 K} 0.2 Fe 1 Co
Represented by the catalyst composition at ₈ Cs _0.4 was prepared as follows. 729.8 g of ammonium heptamolybdate was dissolved in 3648.1 g of warm water at about 50 ° C. (A
liquid). Also, 275.2 g of bismuth nitrate, 7.0 g of potassium nitrate, 30.0 g of neodymium nitrate, and prasedim nitrate 2
9.8, 139.6 g of iron nitrate, 804.7 cobalt nitrate
g and 26.9 g of cesium nitrate were dissolved in 450.4 g of a 15% by weight aqueous nitric acid solution (solution B). After stirring and mixing both solutions A and B for about 2 hours, this mixed solution was spray-dried, and the obtained spray-dried catalyst was further dried at 200 ° C. for 3 hours.
It was calcined for hours. The calcined catalyst of pseudo spherical particles thus obtained was tableted into a column having a diameter of 5 mm and a height of 4 mm, and the tablet was molded.
It was baked at 20 ° C. for 3 hours.

As an initial performance evaluation of the catalyst, 4.0 g of the tableting catalyst was charged into a jacketed SUS reaction tube having a diameter of 10 mm, and at a reaction temperature of 350 ° C., 6% by volume of isobutylene.
9.0% by volume of oxygen, 10.0% by volume of water vapor and nitrogen 7
100 ml / min mixed gas consisting of 5.0% by volume
Aeration was performed at a flow rate of (NTP) to perform a methacrolein synthesis reaction, and the reaction was evaluated. As a result, isobutylene conversion was 97.3%, methacrolein selectivity was 86.4%,
The methacrolein yield was 84.1% and the methacrylic acid selectivity was 2.4%.

Next, as a test for heat resistance and reduction resistance, the reaction temperature was increased to 470 ° C., the flow rate of the above mixed gas was changed to 200 ml / min (NTP), and the unreacted oxygen after the reaction was reduced to 1.0 volume. 50% or less
A continuous operation for 0 hours was performed. When the conversion of isobutylene decreases due to a decrease in the catalytic activity after the start of the reaction, and the amount of unreacted oxygen becomes 1.0% by volume or more, the oxygen in the raw material gas is reduced, and the amount of the reduced oxygen is reduced. The amount was supplemented with the amount of nitrogen gas, and the reaction was performed so that the total amount of the raw material gas was constant. Five hours after the start of the reaction, the conversion of isobutylene was 97.8%, the selectivity for methacrolein was 82.1%,
The methacrolein yield was 80.3% and the methacrylic acid selectivity was 4.5%. 100 hours after the start of the reaction, the reaction results were as follows: isobutylene conversion: 95.8%, methacrolein selectivity: 82.5, methacrolein yield: 79.0%,
The methacrylic acid selectivity was 4.3%. Reaction start 50
The reaction result after 0 hour shows that the conversion of isobutylene is 95.9.
%, Methacrolein selectivity was 82.6%, methacrolein yield was 79.2%, and methacrylic acid selectivity was 4.4%. After the start of the reaction, the conversion of isobutylene tended to decrease up to 100 hours, but was stable thereafter. 10 minutes before the catalyst becomes steady under the above reaction conditions
It was suggested that about 0 hours were required. 50
When the catalyst was extracted after the reaction for 0 hours, discoloration of the catalyst,
No shrinkage was observed.

As a catalyst life test, 4.0 g of this tableting catalyst was charged into a jacketed SUS reaction tube having a diameter of 10 mm, and a 6% by volume isobutylene solution at a reaction temperature of 420 ° C.
9.0% by volume of oxygen, 10.0% by volume of water vapor and nitrogen 7
A mixed gas consisting of 5.0% by volume is 160 ml / min.
Aeration was performed at a flow rate of (NTP) to perform a methacrolein synthesis reaction, and the reaction was evaluated for 8000 hours. As a result, after 20 hours from the start of the reaction, the conversion of isobutylene was 9%.
7.6%, methacrolein selectivity 85.6%, methacrolein yield 83.5%, methacrylic acid selectivity 2.
8%. After 8000 hours from the start of the reaction, the conversion of isobutylene was 97.7%, the selectivity for methacrolein was 85.7%, and the yield of methacrolein was 83.7.
% And methacrylic acid selectivity was 2.7%.

[0035]

Comparative Example 1 Mo ₁₂ Bi _1.6 K _0.2 Fe ₁ Ce _0.4 Co
_{An 8} Cs _0.4 composition catalyst was produced in the same manner as in Example 1. In producing this catalyst, Mo, Bi, K, Co
The same raw material as in Example 1 was used as a Cs source, and cerium nitrate was used as a cerium raw material.

The initial performance evaluation was performed in the same manner as in Example 1.
As a result, the conversion of isobutylene was 97.3%, the selectivity for methacrolein was 87.1%, and the yield of methacrolein was 8%.
4.7%, methacrylic acid selectivity was 2.5%. Next, tests for heat resistance and reduction resistance were performed in the same manner as in Example 1. 5 hours after the start of the reaction,
The isobutylene conversion was 97.8%, the methacrolein selectivity was 82.6%, the methacrolein yield was 80.6%, and the methacrylic acid selectivity was 4.5%. Reaction start 100
After the time, the conversion of isobutylene was 93.4%, the selectivity of methacrolein was 80.7%, the yield of methacrolein was 75.4%, and the selectivity of methacrylic acid was 4.1%. 500 hours after the start of the reaction, the results show that the isobutylene conversion was 86.5%, the methacrolein selectivity was 81.9%,
The methacrolein yield was 70.8% and the methacrylic acid selectivity was 3.6%. Compared with Example 1, the conversion of isobutylene was reduced after 100 hours, and deterioration of the catalytic activity was observed. Some discoloration and shrinkage of the catalyst were observed.

A catalyst life test was performed in the same manner as in Example 1. As a result, 20 hours after the start of the reaction, the conversion of isobutylene was 97.5%, the selectivity for methacrolein was 86.6%, and the yield of methacrolein was 84.4.
% And methacrylic acid selectivity was 2.9%. After 8000 hours from the start of the reaction, the conversion of isobutylene was 96.3%, the selectivity of methacrolein was 86.8%, the yield of methacrolein was 83.6%, and the selectivity of methacrylic acid was 3.0%. Was.

[0038]

Examples 2-32 and Comparative Examples 2-10 Examples 2-32
The catalysts of Comparative Examples 2 to 10 were produced in the same manner as in Example 1. In producing these catalysts, Mo, Bi,
The same raw materials as in Example 1 were used as Pr, Nd, Co and Cs sources. When lanthanum, samarium, europium, gadolinium, terbium, dysprosium, yttrium, cerium, manganese, nickel, and rubidium were included, respective nitrates were used. In Examples and Comparative Examples, when the atomic ratio of Pr to Nd is 1: 3.41,
A solution prepared by dissolving a didymium oxide containing Pr and Nd in an atomic ratio of 1: 3.41 in nitric acid was used. Examples 2-32,
The catalysts of Comparative Examples 2 to 10 were fired at the temperatures shown in Tables 1 and 2, respectively, and the firing time was all three hours.

The catalysts of Examples 2 to 32 were evaluated for initial performance in the same manner as in Example 1. Further, tests for heat resistance and reduction resistance were performed in the same manner as in Example 1, and the results are described in Tables 3 to 6, respectively. Initial performance evaluations of the catalysts of Comparative Examples 2 to 10 were performed in the same manner as in Example 1. Further, tests for heat resistance and reduction resistance were performed in the same manner as in Example 1, and the results are described in Tables 7 to 10, respectively.

From the examples and comparative examples, it can be seen from the examples that praseodymium, neodymium, lanthanum, samarium, europium, gadolinium, terbium, dysprosium, and yttrium are contained in the catalyst component in a specific atomic ratio range, resulting in heat resistance.
It has been found that a catalyst having excellent reduction resistance and catalyst life is obtained.

[0041]

[Table 1]

[0042]

[Table 2]

[0043]

[Table 3]

[0044]

[Table 4]

[0045]

[Table 5]

[0046]

[Table 6]

[0047]

[Table 7]

[0048]

[Table 8]

[0049]

[Table 9]

[0050]

[Table 10]

[0051]

According to the present invention, isobutylene and t-
At least one selected from the group consisting of butyl alcohol
In a method for producing methacrolein by subjecting a seed to gas phase catalytic oxidation using a molecular oxygen-containing gas in the presence of an oxidation catalyst composition, a catalyst having excellent reduction resistance and heat resistance and a long life can be provided.

Continuation of the front page (51) Int.Cl. ⁶ Identification symbol FI // C07B 61/00 300 C07B 61/00 300

Claims (8)

[Claims] An oxide catalyst composition for producing methacrolein by reacting at least one selected from the group consisting of isobutylene and t-butyl alcohol with a molecular oxygen-containing gas represented by the following formula (I): . During _{Mo 12 Bi a A b K c} Fe d Ce e B f C g O h (I) ( wherein, Mo is molybdenum, Bi is bismuth, K is potassium, Fe is iron, Ce is cerium, A is praseodymium , Neodymium, lanthanum, samarium, europium, gadolinium, terbium, dysprosium, yttrium or a mixture thereof, and B is cobalt alone, nickel alone, or a mixture of two or more selected from the group consisting of cobalt, nickel and magnesium. hand,
The ratio of magnesium to cobalt and nickel in the mixture is 0 ≦ magnesium / (cobalt + nickel + magnesium) ≦ 0.5, and C is rubidium, cesium or a mixture thereof. a, b, c, d,
e, f, g, and h are respectively bismuth, A, potassium, iron, cerium, B, C with respect to 12 molybdenum atoms.
And the atomic ratio of oxygen, 0 <a ≦ 8, 0 <b ≦ 8, 0 <c ≦ 1.2, 0 <d ≦ 2.5, 0 ≦ e ≦ 2, 1.0 ≦ f ≦ 12, 0 <g ≦ 2.0 h is the number of atoms necessary to satisfy the valence conditions of the other elements present, and a, b, c, d and e are represented by the following formula: 0.05 ≦ (b + e) The following condition is satisfied: /(a+b+c+e)≦0.70<c/(a+b+c+e)≦0.40<d/(a+b+d+e)≦0.9 ) 2. The formula (I) wherein a, b, c, and e are 0.
The oxide catalyst composition according to claim 1, which satisfies a condition of 1 ≦ (b + e) / (a + b + c + e) ≦ 0.5. 3. The method according to claim 1, wherein a, b, c, and e are equal to 0.
The oxide catalyst composition according to claim 1, which satisfies a condition of 02 ≦ c / (a + b + c + e) ≦ 0.2. 4. The method according to claim 1, wherein a, b, d and e in the formula (I) are equal to 0.
The oxide catalyst composition according to claim 1, which satisfies a condition of 1 ≦ d / (a + b + d + e) ≦ 0.5. 5. A method for producing methacrolein by subjecting at least one selected from the group consisting of isobutylene and t-butyl alcohol to gas phase catalytic oxidation using a molecular oxygen-containing gas in the presence of an oxidation catalyst composition. A method for producing methacrolein, comprising using the oxide catalyst composition represented by the following formula (I): During _{Mo 12 Bi a A b K c} Fe d Ce e B f C g O h (I) ( wherein, Mo is molybdenum, Bi is bismuth, K is potassium, Fe is iron, Ce is cerium, A is praseodymium , Neodymium, lanthanum, samarium, europium, gadolinium, terbium, dysprosium, yttrium or a mixture thereof, and B is cobalt alone, nickel alone, or a mixture of two or more selected from the group consisting of cobalt, nickel and magnesium. hand,
The ratio of magnesium to cobalt and nickel in the mixture is 0 ≦ magnesium / (cobalt + nickel + magnesium) ≦ 0.5, and C is rubidium, cesium or a mixture thereof. a, b, c, d,
e, f, g, and h are respectively bismuth, A, potassium, iron, cerium, B, C with respect to 12 molybdenum atoms.
And the atomic ratio of oxygen, 0 <a ≦ 8, 0 <b ≦ 8, 0 <c ≦ 1.2, 0 <d ≦ 2.5, 0 ≦ e ≦ 2, 1.0 ≦ f ≦ 12, 0 <g ≦ 2.0 h is the number of atoms necessary to satisfy the valence conditions of the other elements present, and a, b, c, d and e are represented by the following formula: 0.05 ≦ (b + e) The following condition is satisfied: /(a+b+c+e)≦0.70<c/(a+b+c+e)≦0.40<d/(a+b+d+e)≦0.9 ) 6. The method according to claim 5, wherein a, b, c and e in the formula (I) satisfy the condition of 0.1 ≦ (b + e) / (a + b + c + e) ≦ 0.5. 7. The method according to claim 5, wherein a, b, c, and e in the formula (I) satisfy the condition of 0.02 ≦ c / (a + b + c + e) ≦ 0.2. 8. The method according to claim 5, wherein a, b, d, and e in the formula (I) satisfy the condition of 0.1 ≦ d / (a + b + d + e) ≦ 0.5.