JPH08309191A - Manufacture of catalyst for synthesis of methacrolein and methacrylic acid - Google Patents

Abstract

PURPOSE: To produce a catalyst for synthesis of methacrolein and methacrylic acid by dividing catalytic components into at least two kinds, making a slurry by mixing solutions or dispersions of respective kinds of components, and producing a composite oxide having a specified formula by drying and firing the slurry. CONSTITUTION: This catalyst is expressed by the formula, Moa Bib Fec Ad Xe Yf Zg Oh (A stands for nickel and/or cobalt; X for at least one element of magnesium, zinc, etc.; Y for at least one element of phosphorus, boron, etc.; Z for at least one element of potassium, sodium, etc.; a-h for atomic ratio of each element and in the case of a=12, 0.1<=b<=5, 0.1<=c<=5, 1<=d<=12, 0<=e<=10, 0<=f<=10, 0.01<=g<=3; and h for the number of oxygen atoms necessary to satisfy the atomic ratios of respective components). To obtain the catalyst, two kinds of solutions or dispersions are mixed for at least 60 seconds to give a slurry-like mixture and after it is heated for at least 30 minutes, the resultant matter is fired.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention is used to synthesize methacrolein and methacrylic acid by gas phase catalytic oxidation of methacrolein and methacrylic acid synthesis catalysts, ie, isobutylene or tertiary butanol with molecular oxygen. The present invention relates to a method for producing a catalyst.

[0002]

2. Description of the Related Art Conventionally, catalysts used for producing methacrolein and methacrylic acid by catalytically oxidizing isobutylene or tertiary butanol under a high temperature gas phase are disclosed, for example, in JP-A-55-127328 and JP-A-SHO. 56-292
6, JP-A-56-161341, JP-A-5
Many proposals have been made in Japanese Patent Publication No. 9-31727 and the like. However, these are mainly related to the components constituting the catalyst and the ratio thereof. Among these, there is almost no description about the preparation method of the catalyst itself.

By the way, Mo-Bi-Fe-based composite oxide catalysts are often used as catalysts for synthesizing methacrolein and methacrylic acid. The method for preparing them is to prepare two or more kinds of solutions or dispersions containing catalyst components. The liquids are mixed, the resulting mixture is heat treated if necessary, then dried,
It is usually prepared by baking the obtained dried product.

Further, Japanese Patent Laid-Open No. 4-182449 discloses that
As a method for preparing a catalyst for synthesizing acrolein or methacrolein, two or more kinds of solutions or dispersions containing a catalyst component are mixed in the shortest possible time, and then the resulting mixture is immediately spray-dried without aging to obtain a mixture. A method for preparing the dried product by baking is disclosed.

However, the catalyst obtained by such a method is still inadequate as an industrial catalyst in terms of catalytic activity and selectivity of a target product, and further improvement is generally desired from an industrial viewpoint.

In view of the current situation as described above, the inventors of the present invention are keenly aware of a method for producing a catalyst used for synthesizing methacrolein and methacrylic acid by gas phase catalytic oxidation of isobutylene or tertiary butanol with molecular oxygen. As a result of examination, the catalytically active basic structure that influences the performance of such a catalyst is
The present invention has been completed by finding that it is almost determined by the process of mixing two or more kinds of solutions or dispersions containing the catalyst component and the subsequent aging process. That is, when the two or more kinds of solutions or dispersions are mixed, particles serving as a precursor of the catalyst structure are generated, and the fine structure of such particles largely depends on the mixing method, particularly the time required for mixing. I understand.

[0007]

DISCLOSURE OF THE INVENTION The present invention provides a catalyst for the synthesis of methacrolein and methacrylic acid, that is, isobutylene or tertiary butanol is subjected to a gas phase catalytic oxidation with molecular oxygen to synthesize methacrolein and methacrylic acid. It is intended to provide a new method for producing a catalyst to be used.

[0008]

The present invention provides the following general formula: Mo _a Bi _b Fe _c A _d X _e Y _f Z _g O _h (wherein Mo, Bi, Fe and O are molybdenum, bismuth and iron, respectively). And oxygen, and A is nickel and / or
Or cobalt, X is at least one element selected from the group consisting of magnesium, zinc, manganese, tin and lead, Y is phosphorus, boron, sulfur, tellurium, silicon, germanium, cerium, niobium, titanium, zirconium,
At least one element selected from the group consisting of tungsten and antimony, and Z represents at least one element selected from the group consisting of potassium, sodium, rubidium, cesium and thallium. However, a, b, c,
d, e, f, g and h represent the atomic ratio of each element, and a = 1
When 2, 0.1 ≦ b ≦ 5, 0.1 ≦ c ≦ 5, 1 ≦ d ≦
12, 0 ≦ e ≦ 10, 0 ≦ f ≦ 10, 0.01 ≦ g ≦ 3
And h is the number of oxygen atoms required to satisfy the atomic ratio of each component. In the method for producing a methacrolein- and methacrylic acid-synthesizing catalyst containing a composite oxide represented by the formula (4) as a catalyst component, in obtaining the composite oxide,
The catalyst component is divided into two or more kinds, at least two kinds of which are made into solutions or dispersions, and the respective solutions or dispersions are mixed for a time of 60 seconds or more to obtain a slurry-like product. A method for producing a catalyst for methacrolein and methacrylic acid synthesis, which comprises subjecting a slurry-like substance to a heat aging treatment for at least 30 minutes, then drying and baking the obtained dried substance to obtain a composite oxide. .

In the present invention, the raw materials for the elements constituting the catalytically active substance are not particularly limited, but are usually oxides, or chlorides, hydroxides, sulfates, nitrates which can be converted into oxides by igniting. , Carbonates, ammonium salts or mixtures thereof.

In the present invention, the method of dividing the catalyst component into two or more kinds is not particularly limited, but as the two kinds of solutions or dispersions containing the catalyst component, a molybdenum compound is added to the first solution or dispersion. A method of using the solution or dispersion containing the bismuth compound and the solution or dispersion containing the bismuth compound in the second solution or dispersion is particularly preferable.

These solutions or dispersions can be prepared by the following method. That is, a suitable molybdenum compound, for example, an aqueous solution in which ammonium molybdate is dissolved in water is used as a first solution, and a compound such as bismuth, iron, cobalt, or cesium, for example, an aqueous solution in which each nitrate is dissolved in dilute nitric acid is used as a second solution. Examples include a method of forming a solution.

In the present invention, when preparing a solution or dispersion containing a catalyst component, a combination may be selected so that each raw material compound does not cause a precipitation-forming reaction, gelation or the like when preparing the solution or dispersion. Therefore, the number of solutions or dispersions containing the catalyst component is usually two or more, but the number is not particularly limited. Further, it is not necessary to prepare all the catalyst components as a solution or dispersion, and depending on the catalyst components, for example, the oxide powder may be used as it is.

In the present invention, the method of mixing two or more kinds of solutions or dispersions containing the catalyst component may be a simple method such as stirring and mixing, which is usually used.

In the present invention, the catalyst precursor particles having a desired structure can be obtained by slowly mixing these for 60 seconds or more. If the time required for mixing is too short, it becomes difficult to control the fine structure of the obtained precipitated particles, particularly the element distribution on the particle surface and inside, and the particle size, and it is often the case that a high-performance catalyst cannot be obtained with good reproducibility.

As a mixing procedure, a method of gently injecting and mixing a solution or dispersion containing bismuth into a solution or dispersion containing a molybdenum compound is particularly preferable.

The slurry-like material containing the catalyst precursor fine particles thus obtained is not immediately dried, but
After heat aging treatment for 30 minutes or more, it is dried. Through this heat aging process, the catalyst precursor structure further grows and becomes more stable. The heat aging treatment temperature is preferably in the range of 80 to 103 ° C.

In the present invention, the method of drying the slurry-like substance after the heat aging treatment is not particularly limited, and a general-purpose box dryer, spray dryer, drum dryer, slurry dryer and the like can be used. The term "drying" in the present invention means removing a certain amount of water from the slurry-like material to make it substantially solid, and there is no particular restriction on the water content after drying. or,
The shape of the dried product is not particularly limited, and may be powder or block.

The method for obtaining the final practical catalyst from the dried product obtained by the above method is not particularly limited,
Usually, the dried product is calcined in the range of 200 to 400 ° C. for about 1 to 5 hours, and subsequently molded or supported on an inert carrier as needed, and then 1 to 20 in the temperature range of 400 to 650 ° C. A method of firing for about an hour is used.

The catalyst obtained by the production method of the present invention is preferably used in a fixed bed as a molded body or a carrier, but it may be used in the form of particles in a fluidized bed.

In producing methacrolein and methacrylic acid by vapor-phase catalytic oxidation of isobutylene or tertiary butanol with molecular oxygen using the catalyst obtained by the present invention, isobutylene or tertiary butanol and oxygen are used. The molar ratio is preferably 1: 0.5-3. The raw material isobutylene or tertiary butanol is preferably diluted with an inert gas before use. The molecular oxygen used for oxidation may be pure oxygen gas, but air is industrially advantageous. The reaction pressure is from normal pressure to several atmospheres. Reaction temperature is 30
The range of 0 to 450 ° C. is preferable.

[0021]

The present invention will be illustrated by the following examples. However, "parts" in Examples and Comparative Examples mean parts by weight. Further, the reaction rate of isobutylene or tertiary butanol as a raw material for reaction and the selectivity of methacrolein and methacrylic acid produced are defined as follows.

[0022]

[Equation 1]

[0023]

[Equation 2]

[0024]

(Equation 3)

Example 1 Ammonium paramolybdate 3000 was added to 6000 parts of water.
Part, 41.3 parts of antimony trioxide and 14.8 parts of germanium dioxide were added and heated and stirred (solution A). Separately water 5
500 parts of 60% nitric acid aqueous solution 100 parts, 85% phosphoric acid aqueous solution 16.3 parts, bismuth nitrate 824.2 parts, ferric nitrate 1029.7 parts, nickel nitrate 1029.2 parts, cobalt nitrate 1647.9 parts, 1053.1 parts of zinc nitrate and 138.0 parts of cesium nitrate were sequentially added and dissolved (B
liquid). While stirring, Solution B was added to Solution A and injected at a substantially constant flow rate for a required time of 200 seconds to form a slurry.

The resulting slurry is heated to 90 ° C.,
It was aged for 60 minutes and subsequently spray dried.

The dried product thus obtained was calcined at 300 ° C. for 1 hour, molded into a cylindrical shape having a diameter and a height of 3 mm, and calcined at 510 ° C. for 3 hours.

The composition of the catalyst thus obtained is represented by the following formula. _{Mo 12 Bi 1 .2 Fe 1.8 Ni} 2.5 Co 4 Zn 2.5 Sb 0.2
P _0.1 Ge _0.1 Cs _0.5 O _x (in the formula, Mo, Bi, Fe, Ni, Co, Zn, Sb,
P, Ge, Cs and O represent molybdenum, bismuth, iron, nickel, cobalt, zinc, antimony, phosphorus, germanium, cesium and oxygen, respectively. The numbers on the right side of the element symbols are the atomic ratios of the respective elements, and x is the number of oxygen atoms required to satisfy the valences of the respective components. )

The catalyst thus obtained was filled in a stainless steel reaction tube, and isobutylene 5%, oxygen 12%, water vapor 1
A raw material mixed gas of 0% and 73% nitrogen was passed through the catalyst layer at a contact time of 4.5 seconds, and reacted at 350 ° C. As a result, as shown in Table 1, the reaction rate of isobutylene is 96.9%,
The selectivity of methacrolein was 88.2% and the selectivity of methacrylic acid was 5.5%.

Example 2 A catalyst was obtained by the same procedure as in Example 1 except that the time required for injecting and mixing the solution B into the solution A was changed to 80 seconds. A reaction was carried out in the same manner as in Example 1 using the obtained catalyst. The results obtained are shown in Table 1. The performance of the obtained catalyst was equivalent to that of Example 1.

Example 3 A catalyst was obtained in the same manner as in Example 1 except that the time required for injecting and mixing the solution B into the solution A was changed to 600 seconds. A reaction was carried out in the same manner as in Example 1 using the obtained catalyst. The results obtained are shown in Table 1.
The performance of the obtained catalyst was equivalent to that of Example 1.

Comparative Example 1 A catalyst was obtained by the same operation as in Example 1 except that the time required for injecting and mixing the solution B into the solution A was changed to 30 seconds. A reaction was carried out in the same manner as in Example 1 using the obtained catalyst. The results obtained are shown in Table 1. The performance of the obtained catalyst was inferior to that of Example 1.

Example 4 Ammonium paramolybdate 3000 was added to 6000 parts of water.
Parts and 110.9 parts of ammonium tungstate were added, and the mixture was heated and stirred to be dissolved (Liquid C). Separately, in 5500 parts of water, 100 parts of 60% nitric acid aqueous solution, bismuth nitrate 892.9
Parts, ferric nitrate 915.3 parts, nickel nitrate 1646.
7 parts, cobalt nitrate 1235.9 parts, magnesium nitrate 363.1 parts, manganese nitrate 81.3 parts, cerium nitrate 61.5 parts, rubidium nitrate 62.6 parts and potassium nitrate 14.3 parts were sequentially added and dissolved (D liquid). Under stirring, C
Liquid D was poured into the liquid at a substantially constant flow rate for a required time of 150 seconds to form a slurry.

The resulting slurry was heated to 100 ° C., aged for 90 minutes, and then spray dried.

The obtained dried product was calcined at 300 ° C. for 1 hour, then molded into a cylindrical shape having a diameter and a height of 3 mm, respectively, and calcined at 510 ° C. for 3 hours.

The composition of the catalyst thus obtained is shown by the following equation. _{Mo 12 Bi 1 .3 Fe 1.6 Ni} 4 Co 3 Mg 1 Mn 0.2 Ce
_0.1 W _0.3 Rb _0.3 K _0.1 O _x (in the formula, Mo, Bi, Fe, Ni, Co, Mg, Mn,
Ce, W, Rb, K and O represent molybdenum, bismuth, iron, nickel, cobalt, magnesium, manganese, cerium, tungsten, rubidium, potassium and oxygen, respectively. The numbers on the right side of the element symbols are the atomic ratios of the respective elements, and x is the number of oxygen atoms required to satisfy the valences of the respective components. )

The catalyst thus obtained was reacted in the same manner as in Example 1. The results are shown in Table 1.

Example 5 A catalyst was obtained in the same manner as in Example 4, except that the aging treatment time was changed to 40 minutes. Using the obtained catalyst, a reaction was carried out in the same manner as in Example 4. The results obtained are shown in Table 1. The performance of the obtained catalyst was equivalent to that of Example 4.

Comparative Example 2 A catalyst was obtained in the same manner as in Example 4, except that the aging treatment time was changed to 10 minutes. Using the obtained catalyst, a reaction was carried out in the same manner as in Example 4. The results obtained are shown in Table 1. The performance of the obtained catalyst was inferior to that of Example 4.

Comparative Example 3 In Example 4, the time required for injecting and mixing the liquid C into the liquid C was changed to 15 seconds, and the obtained slurry was immediately spray-dried without aging. Others are Example 4
A catalyst was obtained by the same procedure as described above. Using the obtained catalyst, a reaction was carried out in the same manner as in Example 4. The results obtained are shown in Table 1. The performance of the obtained catalyst was significantly inferior to that of Example 4.

[0041]

[Table 1]

Example 6 Ammonium paramolybdate 3000 was added to 6000 parts of water.
Parts were added, and the mixture was heated and stirred to dissolve (Part E). Separately 55
100 parts of 60% nitric acid aqueous solution, 8.8 parts of boric acid
Bismuth nitrate 1030.3 parts, ferric nitrate 1144.1
Parts, cobalt nitrate 2059.9 parts, magnesium nitrate 7
26.2 parts, 110.4 parts of cesium nitrate and 37.7 parts of thallium nitrate were sequentially added and dissolved (solution F). Under stirring, E
Liquid F was poured into the liquid at a substantially constant flow rate for a required time of 300 seconds to form a slurry.

Tellurium dioxide 9 was added to the obtained slurry.
0.4 parts and 22.6 parts of titanium dioxide were added as powders, followed by heating to 85 ° C. and aging treatment for 120 minutes, followed by spray drying.

The dried product thus obtained was calcined at 300 ° C. for 1 hour, then molded into a cylindrical shape having a diameter and a height of 3 mm, respectively, and calcined at 510 ° C. for 3 hours.

The composition of the catalyst thus obtained is shown by the following formula. _{Mo 12 Bi 1 .5 Fe 2 Co} 5 Mg 2 Ti 0.2 B 0.1 Te 0.4
Cs _0.4 Tl _0.1 O _x (in the formula, Mo, Bi, Fe, Co, Mg, Ti, B, T
e, Cs, Tl and O represent molybdenum, bismuth, iron, cobalt, magnesium, titanium, boron, tellurium, cesium, thallium and oxygen, respectively. The numbers on the right side of the element symbols are the atomic ratios of the respective elements, and x is the number of oxygen atoms required to satisfy the valences of the respective components. )

Using the catalyst thus obtained, a reaction was carried out in the same manner as in Example 1 except that the starting material for the reaction was changed to tertiary butanol instead of isobutylene. Table 2 shows the results
Shown in

Comparative Example 4 A catalyst was obtained in the same manner as in Example 6 except that the time required for injecting and mixing the liquid F into the liquid E was changed to 20 seconds. A reaction was carried out in the same manner as in Example 6 using the obtained catalyst. The obtained results are shown in Table 2. The performance of the obtained catalyst was inferior to that of Example 6.

[0048]

[Table 2]

[0049]

EFFECTS OF THE INVENTION According to the method for producing a catalyst for methacrolein and methacrylic acid synthesis of the present invention, a catalyst excellent in catalytic activity and selectivity of a target product can be easily and reproducibly produced.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location B01J 37/04 102 B01J 37/04 102 37/08 37/08 C07C 47/22 9049-4H C07C 47 / 22 A 57/05 9450-4H 57/05 // C07B 61/00 300 C07B 61/00 300

Claims (2)

[Claims] 1. The following general formula Mo _a Bi _b Fe _c A _d X _e Y _f Z _g O _h (wherein Mo, Bi, Fe and O represent molybdenum, bismuth, iron and oxygen, respectively, and A is nickel). as well as/
Or cobalt, X is at least one element selected from the group consisting of magnesium, zinc, manganese, tin and lead, Y is phosphorus, boron, sulfur, tellurium, silicon, germanium, cerium, niobium, titanium, zirconium,
At least one element selected from the group consisting of tungsten and antimony, and Z represents at least one element selected from the group consisting of potassium, sodium, rubidium, cesium and thallium. However, a, b, c,
d, e, f, g and h represent the atomic ratio of each element, and a = 1
When 2, 0.1 ≦ b ≦ 5, 0.1 ≦ c ≦ 5, 1 ≦ d ≦
12, 0 ≦ e ≦ 10, 0 ≦ f ≦ 10, 0.01 ≦ g ≦ 3
And h is the number of oxygen atoms required to satisfy the atomic ratio of each component. In the method for producing a methacrolein- and methacrylic acid-synthesizing catalyst containing a composite oxide represented by the formula (4) as a catalyst component, in obtaining the composite oxide,
The catalyst component is divided into two or more kinds, at least two kinds of which are made into solutions or dispersions, and the respective solutions or dispersions are mixed for a time of 60 seconds or more to obtain a slurry-like product. A method for producing a catalyst for methacrolein and methacrylic acid synthesis, which comprises subjecting the slurry-like material to a heat aging treatment for at least 30 minutes, then drying and baking the obtained dried material to obtain a composite oxide. 2. A solution or dispersion containing a molybdenum compound in a first solution or dispersion and a solution containing a bismuth compound in a second solution or dispersion as the solution or dispersion containing two types of catalyst components. Alternatively, the production method according to claim 1, wherein a dispersion liquid is used.