JPH05286886A - Production of methacrolein - Google Patents

Abstract

(57) [Summary] [Object] To provide a gas-phase catalytic oxidation catalyst for producing methacrolein from isobutylene or tert-butyl alcohol at a lower reaction temperature and in a high yield. [Structure] A multi-component oxidation catalyst containing copper, bismuth, iron, molybdenum and cobalt as essential components and additionally containing other specific elements (cesium, lithium, barium, etc.).
The composition formula of a typical catalyst is Cu _0.92 Bi _0.92 Fe _1.85 Mo ₁₂
Co _7.38 Cs _0.36 .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oxidation catalyst used for producing methacrolein (including methacrylic acid as an active ingredient) by a gas phase catalytic oxidation reaction of isobutylene or tertiary butyl alcohol.

[0002]

2. Description of the Related Art In general, a number of patents have been filed relating to improvements in a method and a catalyst for industrially producing methacrolein in a high yield by vapor-phase catalytic oxidation of isobutylene or tertiary butyl alcohol. Among these many catalysts, the molybdenum-bismuth-based catalyst is excellent and has been improved in the direction of multi-components.

For example, JP-A-50-47917 discloses a catalyst for the production of acrolein or acrylonitrile by vapor phase oxidation of propylene, which has the following general formula: Mo _{12
^{Bi a Me 1 b Me 2 c}} Me 3 d Me 4 e Me 5 f O g [ wherein, Me
¹ is In, La, Ga and / or Al, Me ² is Fe and / or Cu, Me ³ is Ni and / or Co, Me ⁴ is P,
B, As, Cr and / or V, Me ⁵ is Tl, Sm, M
g, Ca, Ba, etc.] is used. However, the conventionally proposed catalysts have problems such as insufficient performance and large deterioration of catalytic activity over time, and are not necessarily satisfactory when used as industrial catalysts for producing methacrolein.

[0004]

SUMMARY OF THE INVENTION The present invention aims to provide a novel catalyst for producing methacrolein from isobutylene or tertiary butyl alcohol at a lower reaction temperature and in a high yield.

[0005]

The inventors of the present invention have molybdenum, bismuth, copper, iron and cobalt as essential components,
Furthermore, they have found that the above problems can be solved by using a multi-component oxidation catalyst containing nickel, chromium, an alkali metal and / or an alkaline earth metal in some cases, and completed the present invention.

According to the present invention, when methacrolein is produced by catalytic gas phase oxidation of isobutylene or tertiary butyl alcohol with a gas containing molecular oxygen, a catalyst represented by the following general composition formula: Cu _a Bi _b Fe _c Mo _d Co _e
A method for producing methacrolein, which comprises using A _f B _g O _x .

In the above composition formula, Cu is copper, Bi is bismuth, Fe is iron, Mo is molybdenum, Co is cobalt, A is at least one element selected from the group consisting of nickel and chromium, and B is an alkali metal. And at least one element selected from the group consisting of alkaline earth metals,
And O represent oxygen. Also, a, b, c, d, e, f, g, x
Are Cu, Bi, Fe, Mo, Co, A, B, respectively.
Represents the number of O atoms, and when fixed as d = 12, a = 0.01
-10, preferably 0.1-5; b = 0.1-10, preferably 0.2
~ 7; c = 0.1 to 20, preferably 0.2 to 10; e = 0.1 to 20,
Preferably 0.5-10; f = 0-20, preferably 0-10; g
= 0 to 10, preferably 0 to 5; and x takes a numerical value that satisfies the oxidation state of the element in the catalyst.

In the catalyst of the present invention represented by the above composition formula, examples of the alkali metal represented by B include lithium, sodium, potassium, rubidium and cesium, and examples of the alkaline earth metal include magnesium and calcium. , Strontium, barium and the like. Among these, potassium, rubidium, and cesium are preferable as the alkali metal, and strontium and barium are preferable as the alkaline earth metal.

The method for producing the catalyst used in the present invention is not limited to a special method, and as long as there is no significant uneven distribution of each component, the well-known evaporation drying method, precipitation method, and oxidation method are used. Various methods such as a material mixing method can be used. As the raw material for each element used in the preparation of the present catalyst composition, not only water-soluble nitrates, but also any substances can be used as long as they constitute the catalyst of the present invention by calcination. For example, ammonium salts, carbonates, organic acid salts, acetates, oxides, halides and the like of each element can be used in combination.

As a method of molding the catalyst, a well-known method such as a coating method, a tableting method and an extrusion molding method can be used. It is also possible to add additives in consideration of catalyst strength, pulverization degree, abrasion degree and the like. For example, it is possible to add polyvinyl alcohol, stearic acid or the like when preparing the catalyst powder, or in some cases, add whiskers, glass fibers or the like. As the powder binder, generally known glass fight, water, cellulose, ammonium nitrate, starch and the like can be used, and an organic solvent such as alcohol can also be used.

The catalyst used in the present invention may be carrier-free, but it may be supported on an inert carrier such as silica sol, silica gel, alumina, or silicon carbide, or may be diluted with these. The catalyst is calcined by pre-calcination and main calcination in an air stream or a nitrogen stream. Usually, the pre-baking temperature is generally 150 to 500 ° C, preferably 200 to 400 ° C, and the main baking temperature is 400 to 500 ° C.
The temperature is 900 ° C, preferably 450 to 700 ° C.

In carrying out the present invention, the concentration of isobutylene or tertiary butyl alcohol in the composition of the raw material gas for the catalytic oxidation reaction can be varied within a wide range.
1-20% by volume is suitable, and 3-10% is particularly preferable. It is economical to use air as the oxygen source, but pure oxygen can also be used. The oxygen concentration in the raw material gas is defined by the molar ratio to isobutylene or tertiary butyl alcohol, and this value is 0.2 to 5, especially 0.4 to 3
Is preferred. The raw material gas may be diluted by adding an inert gas such as nitrogen, carbon dioxide or water vapor. The reaction pressure is from normal pressure to
10 atm, reaction temperature 250 ~ 500 ℃, space velocity 1
You can choose from the range of 00-5000 hr ^-1 (STP),
The reaction can be carried out in a fixed bed or a fluidized bed.

[0013]

EXAMPLES Next, a method for preparing the catalyst according to the present invention and a reaction example using the same will be specifically described with reference to Examples and Comparative Examples. The catalyst loading rate, conversion rate, selectivity and total single-flow yield described in the following examples are defined as follows.

[0014]

[Equation 1]

Example 1 75.99 g of ammonium paramolybdate was added to pure water 33
It was dissolved in 0 g at 70 ° C. To this, 28.97 g of iron nitrate and 83.48 g of cobalt nitrate dissolved in 50 g of pure water were added, and 1.398 g of cesium nitrate was added to 2 parts of pure water.
What was dissolved in 0 g was added, and then bismuth subcarbonate 9.
After adding 384 g, 4.332 g of copper nitrate was added to 20 g of pure water.
Was added to the solution, heated to 80 ° C. with stirring, and after 2 hours, pre-baking was performed in air at 300 ° C. for 1 hour. The obtained solid matter was ground in pure water, and a spherical alumina carrier having a diameter of 5 mmφ was added to this slurry so that the catalyst supporting rate was 18% by weight, and the mixture was evaporated to dryness,
What was calcined in air at 520 ° C for 4 hours was used as a catalyst.

The elemental composition of the obtained catalyst excluding oxygen is
The atomic ratio was Cu _0.5 Bi ₁ Fe ₂ Mo ₁₂ Co ₈ Cs _0.2 . The reaction tube was filled with this catalyst, and isobutylene 6%,
A mixed gas of oxygen 12% and nitrogen 82% (volume%) was reacted at a reaction temperature of 350 ° C. and a space velocity of 360 h ⁻¹ . The results are shown in Table-1.

Example 2 74.92 g of ammonium paramolybdate was dissolved in 330 g of pure water at 70 ° C. To this, 28.57 g of iron nitrate and 82.31 g of cobalt nitrate dissolved in 50 g of pure water were added, and further, 1.378 g of cesium nitrate dissolved in 20 g of pure water was added, and then 9.252 g of bismuth subcarbonate was added. After that, copper nitrate 8.5
A solution obtained by dissolving 42 g in 20 g of pure water was added, the temperature was raised to 80 ° C. with stirring, and after 2 hours, pre-baking was performed in air at 300 ° C. for 1 hour. The obtained solid matter was crushed in pure water, and the slurry had a catalyst loading of 18% by weight.
Spherical alumina carrier with a diameter of 5 mm
Evaporated to dryness and calcined under air at 520 ° C for 4 hours was used as a catalyst.

The elemental composition of the obtained catalyst excluding oxygen is
The atomic ratio was Cu ₁ Bi ₁ Fe ₂ Mo ₁₂ Co ₈ Cs _0.2 . This catalyst was filled in a reaction tube, and a mixed gas of 6% isobutylene, 12% oxygen and 82% nitrogen (volume%) was reacted at a reaction temperature of 350 ° C. and a space velocity of 360 h ⁻¹ . The results are shown in Table-1.

Example 3 77.24 g of ammonium paramolybdate was dissolved in 330 g of pure water at 70 ° C. To this, 27.18 g of iron nitrate and 78.32 g of cobalt nitrate dissolved in 50 g of pure water were added, and further, 1.311 g of cesium nitrate dissolved in 20 g of pure water was added, followed by the addition of 8.804 g of bismuth subcarbonate. After the copper nitrate 8.1
A solution obtained by dissolving 28 g in 20 g of pure water was added, the temperature was raised to 80 ° C. with stirring, and after 2 hours, pre-baking was performed in air at 300 ° C. for 1 hour. The obtained solid was crushed in pure water, and the slurry was loaded with a catalyst of 18% by weight.
Spherical alumina carrier with a diameter of 5 mm
Evaporated to dryness and calcined under air at 520 ° C for 4 hours was used as a catalyst.

The elemental composition of the obtained catalyst excluding oxygen is
Cu _0.92 Bi _0.92 Fe _1.85 Mo ₁₂ Co _7.38 Cs in atomic ratio
It was _0.18 . This catalyst was filled in a reaction tube, and a mixed gas of 6% isobutylene, 12% oxygen and 82% nitrogen (volume%) was reacted at a reaction temperature of 350 ° C. and a space velocity of 360 h ⁻¹ . The results are shown in Table-1.

Examples-4 to 12 Each catalyst shown in Table-1 was prepared according to Example-3, and Example-
The reaction was performed under the same conditions as in Example 3, and the results shown in Table 1 were obtained.

Example-13 Using the catalyst obtained in Example-3, tert-butyl alcohol was used in place of isobutylene to carry out the reaction. The same reaction was performed except that 6% by volume of tertiary butyl alcohol was used instead of the reaction conditions of Example-3. The reaction results are as follows: tertiary butyl alcohol conversion 100.0 mol%, methacrolein selectivity 8
The results were 3.6%, methacrylic acid selectivity was 3.3%, and isobutylene was 0.9%. Even if the isobutylene was replaced with tertiary butyl alcohol, the results were found to be almost the same.

Comparative Example-1 Comparative catalyst according to Example-1: Bi ₁ Fe ₂ Mo ₁₂ Co ₈
Cs _0.2 was prepared and reacted under the same conditions as in Example-1, and the results shown in Table-1 were obtained. Comparative Example-2 The reaction was carried out under the same conditions as in Example-1, except that the catalyst of Comparative Example-1 was used and the reaction temperature was 370 ° C, and the results shown in Table-1 were obtained.

[0024]

[Table 1]

[0025]

The present invention is characterized in that a specific amount of copper is introduced into a multi-component catalyst containing bismuth, molybdenum, iron and other specific elements. As a result, the activity is remarkably improved and a high yield can be achieved even at a lower reaction temperature. Therefore, the high catalytic activity is maintained for a long period of time, so that the industrial value is extremely high.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location // C07B 61/00 300

Claims (1)

[Claims] 1. A catalyst represented by the following general composition formula is used when methacrolein is produced by catalytic gas-phase oxidation of isobutylene or tert-butyl alcohol with a gas containing molecular oxygen. Manufacturing method. _{Cu a Bi b Fe c Mo d} Co e A f B g O x
[In the formula, Cu is copper, Bi is bismuth, Fe is iron, Mo is molybdenum, Co is cobalt, A is at least one element selected from the group consisting of nickel and chromium, B is an alkali metal and an alkaline earth metal. At least one element selected from the group consisting of metals and O represents oxygen. Also, a, b, c, d, e, f, g and x are Cu, Bi and F, respectively.
Represents the number of atoms of e, Mo, Co, A, B, O, d = 12
When fixed as, a = 0.01 to 10, b = 0.1 to 10, c = 0.1
~ 20, e = 0.1 to 20, f = 0 to 20, g = 0 to 10, and x
Is a value that satisfies the oxidation state of the elements in the catalyst]