JPS6028824A - Catalyst for manufacturing methacrolein - Google Patents

Abstract

PURPOSE:To manufcture a catalyst capable of obtaining methacrolein at a temp. lower than before with high selectivity and yield by adding Mo, Fe, Co, alkali metal, P, Si, etc. to Bi and W which are previously treated at high temps., and calcining in an air stream. CONSTITUTION:The composition is expressed by the formula Mo12BiaWbFecAd BeCfDgOh, where A is an element selected from Co and Ni, B is an element selected from alkali metal, alkaline earth metal, and Tl, C is an element selected from P, Sb, Sn, Ce, Pb, and Nb, and D is an element selected from Si, Al, Ti, and Zr. When Mo is regulated to 12 and a-h are expressed in the atomic ratios, a=0.1-10.0, b=0.5-10.0, a/b=0.01-6.0, c=0.1-10.0, d=2.0-20.0, e= 0.01-10.0, f=0-10.0, g=0-30, and h is a numerical value determined by the valency of each element. Bi and W are introduced as an oxide obtained by previously calcining a mixture of a Bi compd. and a W compd. at 600-900 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a catalyst for the catalytic gas phase oxidation of isobutylene or tertiary-butanol with a molecular oxygen gas to yield methacrolein and methacrylic acid.

Specifically, the present invention involves catalytic gas phase oxidation of isobutylene or tert-butanol using a molecular oxygen-containing gas such as air to produce methacrolein and methacrylic acid.
In particular, the present invention mainly relates to a catalyst for obtaining methacrolein with high selectivity and good yield, and provides a catalyst that can be used industrially for a long period of time and stably.

Conventionally, many proposals have been made as catalysts for producing the corresponding unsaturated aldehydes by catalytic gas phase oxidation of oleenoin. Examples include catalyst systems based on molybdenum and bismuth. To give a concrete example, the special public relations system of 1977-
The specification of Japanese Patent Publication No. 3563 describes a catalyst consisting of bismuth molybdate and bismuth phosphomolybdate;
! 50 76010, a catalyst containing molybdenum, cobalt, and iron as constituent elements was disclosed in
No. 3670 Specification II Catalyst containing iron, bismuth, phosphorus and molybdenum as constituent elements, U.S. Patent No. 3,
No. 522.299 specifies h nickel, cobalt, iron,
Catalytic oxides containing bismuth, molybdenum, phosphorus, and arsenic as constituent elements are each disclosed as i1.

On the other hand, there are catalyst systems mainly based on tungsten and bismuth; for example, U.S. Pat.
A bismuth-, cobalt-, and tungsten-based catalytic silk composition is proposed in the specification of Japanese Patent No. 8017, IF.

Furthermore, catalyst systems based on molybdenum, bismuth, and tungsten have also been proposed. For example, JP-A-49-1994
9Q, and JP-A No. 49-14393, and the specification of JP-A-47-42241 describes a catalyst composition containing molybdenum, cobalt, iron, bismuth, tungsten, silicon, and an alkali metal as constituent elements. is proposed.

However, many of these publications mainly focus on catalysts for producing acrolein and acrylic acid by catalytic gas-phase oxidation of propylene, and although some disclosures are made regarding catalysts for producing methacrolein, there are no working examples. Even if there were some examples, most of them were of very low yields and far from being suitable for industrial use. In recent years, various improvements have been made to K, and some catalysts whose main purpose is to produce methacrolein have reached the level of oJ performance that can be used industrially.

However, when considering the use of these innovative catalysts on an industrial scale, it is not possible to obtain methacrolein and methacrylic acid with high selectivity and high yield as described in their specifications and examples. There are many cases. This is because the catalytic gas phase oxidation reaction is extremely exothermic, so a hot spot, a locally abnormally high temperature zone, occurs in the catalyst layer, causing an excessive oxidation reaction, or the height of the catalyst packed bed is large. Therefore, the pressure in the catalyst layer changes sequentially from the inlet to the outlet of the catalyst layer, which may deviate from the ideal reaction.

On the other hand, in multicomponent catalysts mainly composed of molybdenum, molybdenum easily reacts with many elements to form complex molybdenum complex salts, making it difficult to obtain homogeneous catalysts and the reproducibility of catalyst performance. There are some drawbacks to this, and when such a catalyst composition is used for catalyst production on an industrial scale, it is quite understandable that the performance of all the produced catalysts will not be able to show the high level of performance as in the Examples of Book #I. be.

As a result of intensive research, the present inventors have developed a preparation method that overcomes the drawbacks of catalyst systems containing molybdenum, bismuth, and tungsten in industrial use, and that also provides excellent reproducibility of catalyst performance in catalyst production on an industrial scale. The present invention has now been completed.

That is, the present invention is based on the general formula % [where MO is molybdenum, Birj bismuth, W is tungsten, Fe is iron, Ai, J: at least IN element selected from cobalt (CO) and nickel (Ni), B is at least III element selected from alkali metals, alkaline earth metals, and thallium (Tl), and C is phosphorus (P), 9-, 3-, antimony (sb), and tin (
At least one element selected from S, n), cerium (Ce), lead (pb), niobium (Nb)... S
i), aluminum (AI), titanium (TJ),
At least one element selected from zirconium (Zr), 0 represents oxygen, as bz C%ds ”s
fsg, h represent the atomic ratio of each element, Mo
When is 12, a=0.1~10.0, b=o-5~
At 10.0, a/b is 0.01-6.01c=o, 1
~10.0, d=2.0~20.0, e is 0.01-1
0.0, f = o ~ 10.0, g = 0 ~ 30, and h
is a numerical value determined by the valence of each element], and is an oxide form obtained by pre-calcining a mixture of a Bt acid component bismuth compound and a tungsten compound at a temperature of 600 to 900°C. The present invention provides a catalyst composition for producing methacrolein and a method for producing the same.

A feature of the catalyst of the present invention is that bismuth forms an extremely stable bond with tungsten and maintains its high catalytic performance even during long-term reactions. This stable bond between bismuth and tungsten is formed by previously treating bismuth and tungsten at a high temperature of 600 to 900°C. Academic research on this compound consisting of bismuth and tungsten has become popular in recent years, for example, in the Journal of Catalysis (Journal of Catalysis).
) Vol. 31, pp. 200-208 (1973) 1,
The existence of various bismuth-tung states has been revealed.

Experiments conducted by the present inventors have also shown that these compounds have activity in the oxidation of isobutylene or tertiary-butanol at high temperatures exceeding 400°C, but the level of activity is not very satisfactory for industrial use. By further combining this bismuth tungstate with molybdenum, iron, and other metal elements, a catalyst composition with good thermal stability, excellent catalytic performance at low temperatures, and high space-time yield can be created. It turns out that things can be changed.

It is true that a proposal to separately prepare a mixture of bismuth and tungsten and add it to the remaining catalyst components has already been made in some of the specifications of JP-A-55-47144 and JP-A-49-9490. However, in this case, no firing was performed in a manner that would form a stable bismuth-tungsten compound in advance.

On the other hand, in catalyst 1v according to the present invention, bismuth and tungsten are pre-treated at high temperature, and by using this, a high-level catalyst with excellent reproducibility can be obtained in the preparation method, and compared to the conventional catalyst. It has been found that this method is extremely advantageous as an industrial preparation method compared to catalyst systems based on bismuth and molybdenum compounds. Furthermore, it should be noted that in the present invention, bismuth is substantially strongly bonded to tungsten, and even after forming a multicomponent catalyst, J, +M-y 2'nol-/7X pregnancy Δ・mu GI J
, Ul)-1/-y --y tfz It has become clear that a catalyst whose shape is further specified as follows is recommended as Δ. That is, 3.0 to 10. O
It has an outer diameter of wII+ and a length of 0.5 to 2.0 times the outer diameter, and has an opening in the length direction so that the inner diameter is 0.1 to 0.7 times the outer diameter. Ring-shaped Kaiyama Mk-
h Hatakeichi Shidou nd) 几 - 入 t I - AU: 1 - 愈中 7 ト 1
1; (II) By using a ring-shaped catalyst, it is naturally expected that the pressure loss in the catalyst layer will be reduced, making it possible to reduce the power cost of the blower in industrial production. .

0ii) Furthermore, the catalyst of the present invention has the advantage that the catalyst life is extended. In other words, increasing the heat removal effect by using a ring-shaped catalyst to reduce the temperature of the locally abnormally high temperature zone that generally occurs because catalytic gas phase oxidation is extremely exothermic;
Combined with the aforementioned reduction in heat generation due to the sequential reaction of methacrylic acid, acetic acid, carbon dioxide, and carbon oxide, the temperature of the hot spot decreases, and the scattering of molybdenum, one of the catalyst components, occurs during the reaction. The rate of increase in pressure loss caused by this decreases, resulting in a longer life of the catalyst.

The catalyst of the present invention has a composition range shown by the above general formula, and its preparation method can be selected from various methods as long as it has the above-mentioned characteristics.

First, regarding the method for producing a combination of bismuth and tungsten, an example of a preferable preparation method is shown below. is thoroughly mixed with a small amount of water, dried, and then treated and pulverized at a high temperature of 600 to 900°C, preferably 700 to 850°C. Although it is better to reduce the size of the powder, it is wasteful to reduce the size of the powder more than necessary, and a particle size of 100 mesh or less is sufficient. In this way, a bismuth-tungsten compound can be obtained. Next, a specific example of preparing a catalyst is shown below: If an iron compound such as an aqueous solution of iron nitrate is added to an aqueous solution of a molybdenum compound such as ammonium molybdate in advance, and cobalt is used as the element A shown in the general formula, For example, an aqueous solution of cobalt nitrate, an alkali total hydroxide or nitrate as an alkali metal source when an alkali metal is used as B, an aqueous phosphoric acid solution when phosphorus is used as C, and colloidal silica when silicon is used as D. Mix each aqueous solution well using a silica etc., add the previously crushed bismuth tungsten binder to the resulting slurry, mix well and concentrate, and mold the resulting clay-like material. 350°C to 650°C, preferably 40°C
The finished catalyst is obtained by firing at a temperature of 0°C to 600°C under air circulation.

Note that, if necessary, a powdered carrier material may be added to the slurry.

The carrier may be selected from silica gel, alumina, silicon carbide, quartz clay, titanium oxide, and Cera-ft (trade name), but in particular silica gel, titanium oxide,
Celite is suitable.

The oxygen-containing compound of bismuth and tungsten, which is a feature of this catalyst, has an atomic ratio of bismuth to tungsten of 0.
It is limited to a range of 0.01 to 6.0, preferably 0.1 to 4.0. That is, bismuth with an atomic ratio exceeding 6.0
Tungsten compounds cannot form a stable bonded state, and during catalyst preparation or long-term use of the catalyst, the bonds of bismuth tungsten break and bismuth recombines with other components, disrupting the bonding balance of each component of the catalyst, which is not desirable. This is because it brings no results. Of course, such an atomic ratio (h
In addition, high-temperature treatment conditions are also an essential requirement.

Oxygen-containing compound of bismuth and tungsten Q'/JIt-
J. forms a stable compound by treatment in such a temperature range, and its incorporation into the catalyst composition of the present invention brings its catalytic performance to a very high level. Heat treatment of a compound of bismuth and tungsten at a low temperature below 600°C will not stabilize it in the catalyst composition even if its atomic ratio satisfies the above range, and it will not be stabilized during catalyst preparation or during catalyst preparation. This is undesirable because it causes the bond balance in the catalyst composition to collapse during use. Further, treatment at a high temperature exceeding 900° C. is also not preferred because it is difficult to obtain a stable combination of bismuth and tangesdesi, and it is likely to change in the catalyst composition.

The catalyst raw materials in the present invention are not limited to the above compounds, but include bismuth and tungsten (such as bismuth chloride), organic acids such as bismuth rogenide, bismuth carbonate, bicarbonate, bismuth hydroxide, and bismuth acetate. Alkali gold salts of tungstic acids such as bismuth salts and sodium tungstate, tungsten halides such as tungsten chlorides, etc. are used as appropriate, but if halides or alkali salts are used, they should be thoroughly washed after filtering the slurry. Needless to say, a thorough cleaning is necessary.

Regarding molybdenum, iron, and other catalyst raw materials, not only nitrates and organic acid salts, but also any compounds that can form their respective oxides can be used in the preparation of the catalyst. Of course, two or three of the elements constituting the above catalyst
Compounds containing seeds may be used as well.

Any method can be used to prepare the catalyst as long as it allows each catalyst component in the catalyst composition to be uniformly mixed. For example, bismuth and tungsten The prepared powder is powdered cobalt, nickel, iron, molybdenum, phosphorus,
antimony, tin, cerium, silicon, aluminum,
A desired catalyst composition can be obtained by mixing with a mixture of oxides such as titanium, adding a binder such as carboxymethyl cellulose which disappears by calcination, and kneading uniformly in the same manner as above.

250-450℃ using the catalyst found in this way.
reaction temperature, under a pressure of normal pressure to 10 atm, 1 to 10 volumes of imbutylene or tertiary butanol, 3 to 2
Oxygen at 0 volume, water vapor at θ~60 volume, and 20~
A raw material gas consisting of an inert gas such as nitrogen gas or carbon dioxide gas having a width of 80 volumes is reacted for a contact time of 1.0 to 100θ seconds.

Further, the catalyst according to the present invention can be used in both fixed bed reactions and fluidized bed reactions, and the selection thereof is within the discretion of those skilled in the art.

EXAMPLES Hereinafter, the present invention will be explained in more detail by showing examples and comparative examples, but the present invention is not limited to the following examples unless it goes against the gist thereof.

In addition, the reaction rate, selectivity, and single flow yield in this invention shall be defined as follows.

Example 1 Bismuth nitrate 2911 was dissolved in 1000 me of distilled water made acidic by adding 62 mg of concentrated nitric acid. To this aqueous solution, 660 mP of aqueous ammonia (2Q-To) was added to obtain a white precipitate. Wash this separately with water F and gill number 1.
After adding 278 tons of tungsten trioxide to the white cake-like substance and thoroughly mixing the mixture, it was dried at 230°C for 16 hours, and then heat-treated at 750°C for 2 hours under air circulation. The obtained yellow lumps were ground to less than 100 meshes to obtain yellow powder. X-ray diffraction analysis of this powder revealed that it was d=2 as shown in the previous literature. c+ 73.3,20
7. Bi2(WOa)3 with a peak at 2.706.1.648.1.915 and d=3.632.3.817.
It was found that it was a mixture of WO3 with a peak at 3.739.2.610, but no bismuth oxide peak was observed.

Separately, add 106 parts of ammonium molybdate to 80 parts of distilled water.
In the aqueous solution dissolved in 00 ml,
An aqueous solution of 31F dissolved in 600ml of distilled water, an aqueous solution of ferric nitrate 711 dissolved in 400ml of distilled water, 300ml of Silica Sol 1502 containing 20% silica by weight, and 25ml of potassium nitrate! A distilled water pressure dissolved aqueous solution was added to each, and the mixture was stirred.

The resulting suspension was concentrated by heating, dried, and then ground. Add the previously colored powder to this powder, boil it thoroughly, and then add distilled water. 6 at 500℃
It is fired for a period of time to form a finished catalyst.

The composition of this catalyst excluding oxygen, tJ, is old in atomic ratio, 2W
,4Ii'e,,3. , Mo12 Co6. . K. , 5
S t□,.

(The catalyst composition will be expressed in the same manner below.)

When the resulting catalyst was subjected to X-ray diffraction analysis, the peak of bismuth tungstate was observed as is, and no peaks related to bismuth combined with other elements other than oxygen, such as bismuth molybdate, were observed.

The thus obtained catalyst was packed into a steel reaction tube with an inner diameter of 25.4 wφ to a bed length of 3000 mvn, and the temperature of the external heat medium (molten salt) was heated to 340°C. Volume ratio, water vapor 10.0 volume ratio, nitrogen 70.
A raw material gas having a composition of 8 volumes was introduced and the contact time was 2.
The reaction was carried out for 5 seconds (NTP conversion W), and the results shown in Table 1 were obtained.

The analysis was performed by gas chromatography.

After reacting with this catalyst for 5,000 hours, it was extracted and subjected to X-ray analysis, and no changes were observed compared to the catalyst before use.

Comparative Example 1 A catalyst having the following composition was prepared in the same manner as #1 in which the high-temperature treated product of bismuth and tungsten was not used in Example 1.

Fe □, 35 Mo 12 Co 6. □ K□, 5
S t 1.0 The obtained catalyst was reacted under the same conditions as in Example 1, and the results shown in Table 1 were obtained.

Comparative Example 2 A catalyst having the following composition was manufactured in the same manner as in Example 1 except that tungsten trioxide was not used.

Btl, 2Fe□, 36 Mo12 Co6. . K. ,
Si1. (.

The obtained catalyst was reacted in the same manner as in Example 1, and the results shown in Table 1 were obtained.

Comparative Example 3 A catalyst having the same composition as the catalyst of Example 1K was obtained by carrying out the same procedure as in Example 1 except that bismuth and tungsten were heat-treated at 500° C. for 2 hours. The resulting catalyst was reacted under the same conditions as in Example 1 and the results shown in Table 1 were obtained.

Example 2 873 tons of bismuth nitrate was dissolved in 1840 me of distilled water which had been made acidic by adding 160 ml of concentrated nitric acid, and heated to 80°C. Sodium tungstate 2972 3500
ml' of water, adjusted the pH to 2.2 with nitric acid, heated to 80°C, and added to the bismuth nitrate solution with stirring. The observed white precipitate was separated by furnace and washed with water until sodium ions were no longer detected. The resulting white cake was treated in the same manner as in Example 1 to obtain a yellow powder.

Separately, ammonium molybdate 1060F is 8000-
An aqueous solution of cobal nitrate 873f dissolved in 800 ml of distilled water, ferric nitrate 2
An aqueous solution of 42F dissolved in 7'00 ml of distilled water,
Silica sol 1502 containing 20 parts by weight of silica and an aqueous solution of 25.6 f of rubidium hydroxide dissolved in 100 me of distilled water were added and stirred at room temperature.

Add 90 ml of concentrated nitric acid to the resulting suspension! After adding 500 f of ammonium nitrate, the above yellow powder was added and contracted to Kf1M while stirring. After molding and drying in the same manner as in Example 1, the mixture was calcined at 500°C under air circulation for 6 hours to obtain a catalyst having the following composition.

Bi3.6W, BFel, 2Mo12Co6Rb(,3
Si1. .

The obtained catalyst was reacted under the same conditions as in Example 1, and the results shown in Table 1 were obtained.

Example 3 485f of bismuth nitrate was dissolved in 1000ml of distilled water which had been made acidic by adding 104ml of concentrated nitric acid. Add ammonia water (28To) to this aqueous solution at 1100 m/! was added to obtain a white precipitate. This was washed separately with F water, and 278 F tungsten trioxide was added to the resulting white cake-like substance and thoroughly mixed, dried at 230° C. for 16 hours, and further treated at 750° C. for 2 hours under air circulation. The yellow lumps found were crushed to less than 100 mesh to obtain yellow powder.

Separately, add 1060f of ammonium molybdate to 80% distilled water.
An aqueous solution in which 873 tons of cobalt nitrate was dissolved in 800 mL of an aqueous solution, and 3232 tons of ferric nitrate was dissolved in 10
100O! of silica sol 1502 containing 20 weight range of silica and cesium nitrate 48.
An aqueous solution of 79 dissolved in 300-distilled red was added to each, and the mixture was stirred at room temperature.

After adding 90 ml of concentrated nitric acid and 5002 ammonium nitrate to the resulting suspension, the above yellow powder was added, concentrated under heating and stirring, molded in the same manner as in Example 1, and then calcined at 500°C under air circulation for 6 hours. A catalyst with the following composition was obtained.

B+2. o W2,4 Fe 1.6 Mo 12
Co 6 S t 1. OCs O,1) The obtained catalyst was reacted under the same conditions as in Example 1, and the results shown in Table 1 were obtained.

Examples 4 to 8 Catalysts having the compositions shown in Table 1 were prepared in the same manner as in Example 1. The oxidation reaction conditions and results of isobutylene are shown in Table 1.

The raw materials used were nickel, thallium, barium, strontium, calcium, magnesium, cerium, and zirconium. Each nitrate was used as a lead source, phosphoric acid was used as a phosphorus source, niobium pentoxide was used as a niobium source, and antimony trioxide was used as an andimony source. , titanium dioxide was used as the titanium source.

Example 9 A catalyst with the same composition and preparation method as Example 1 was prepared with an outer diameter of 6.0.
The fin was molded into a ring shape with a length of 6.6+mm and a hole diameter of 2.0, and the same reaction as in Example 1 was conducted to obtain the results shown in Table IK.

Example 10 Using the catalyst of Example 2 and using tertiary-butanol in place of imbutylene, tertiary-butanol was 6 volumes, oxygen was 13.2 volumes, water vapor was 4 volumes, and nitrogen was 76 volumes.
．． A raw material gas having a composition of 8 volumes was introduced and the contact time was 2.
．． The reaction was carried out for 5 seconds at a molten salt temperature of 330°C, and the following results were obtained.

Tertiary-butanol reaction rate 100% inbutylene selectivity 1.5 methacrolein # 85.2, itacrylic acid l 2.6 Imbutylene single stream yield 1.5 qb methacrolein # 85.2 methacrylic acid l 2 .6 section

Claims (1)

[Claims] (1) Isobutylene or tertiary-butanol Mo
12 old, WbFecAdBeCfDgOh (however, at least 1 selected from cobalt and nickel)
The species element, B, is at least lf selected from alkali metals, alkaline earth metals and thallium! , C is at least one element selected from phosphorus, antimony, tin, cerium, lead, and niobium, and D is at least one element selected from silicon, aluminum, titanium, and zirconium.
Represents the species element as bs as d-, 8% fl
gs h represents the atomic ratio of each element, and when molybdenum is 12, a=0.1 to I O,0, b=0+
5-10.0, a/b is 0, O1-6.0, c=
0.1-10.0, d=2.0-20.0. q is 0.01~1000, f=0~10.0, g=
(0 to 30, h is a value determined by the valence of each element), and the Bi acid component W component is prepared by preparing a mixture of a bismuth compound and a tungsten compound at a temperature of 600 to 900°C in advance. A catalyst composition for producing methacrolein, characterized in that it is introduced in the form of an oxide obtained by calcination treatment.