JP2003117394A - Catalyst for dehydrogenation reaction of ethylbenzene under coexistence of carbon dioxide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a catalyst exhibiting high activity when ethylbenzene is dehydrogenated under coexistence of carbon dioxide to manufacture styrene. SOLUTION: The catalyst for dehydrogenation reaction of ethylbenzene comprises iron oxide, aluminum oxide and cerium oxide as essential components and preferably the contents of the iron oxide, aluminum oxide and cerium oxide are 5-20% wt.%, 65-94 wt.% and 1-15 wt.%, respectively, when the sum total of the catalyst is 100 wt.%.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a catalyst used for producing a styrene monomer by dehydrogenating ethylbenzene in the presence of carbon dioxide.

[0002]

2. Description of the Related Art Conventionally, in order to industrially produce a styrene monomer, ethylbenzene was added in the presence of a large amount of steam.
A method in which a catalyst containing iron oxide and potassium as main components is contacted at a temperature of about 600 ° C. (catalyst, 38
Vol. 7, No. 572-579 (1996)). However, this method requires a large amount of water vapor to coexist.
There are also points to be improved such as high energy consumption, need to carry out the reaction under reduced pressure in order to increase the single yield of styrene monomer, and volatilization of potassium in the catalyst during the reaction. It has been pointed out. In order to solve these problems, the present inventors previously used carbon dioxide instead of water vapor as a coexisting gas,
It has been reported that the energy consumption is lower than that in the conventional process, and the single yield of styrene monomer may be higher (Catalysis Today, 55 (2000) 173-178). However, even in this new method using carbon dioxide, an excellent catalyst is required, and the present inventors have already developed a catalyst composed of iron oxide, calcium oxide and aluminum oxide (Japanese Patent No. 3032816). .

[0003]

DISCLOSURE OF THE INVENTION The present invention is a further development and leap forward of such a patented invention. In the method for producing a styrene monomer by subjecting ethylbenzene to a dehydrogenation reaction in the presence of carbon dioxide, the method is further improved. An object is to provide a high-performance catalyst.

[0004]

As a result of studying the influence of various additives on the performance of a catalyst composed of iron oxide and aluminum oxide, the present inventor has surprisingly found that the problem is caused by the catalyst containing cerium oxide. Found that it could be solved.

That is, according to the present invention, firstly, iron oxide,
Provided is a catalyst containing aluminum oxide and cerium oxide as essential components and showing high performance in an ethylbenzene dehydrogenation reaction in the presence of carbon dioxide. Secondly, in the first invention, a catalyst containing iron oxide, aluminum oxide and cerium oxide as essential components, wherein the whole catalyst is 1
When it is set to 00% by weight, the content of each oxide is 5 to 30% by weight, 55 to 94% by weight, and 1 to 15% by weight in the above order.
A catalyst for ethylbenzene dehydrogenation reaction in the presence of carbon dioxide is provided. Thirdly, there is provided a method for producing a styrene monomer, which comprises contacting ethylbenzene with the catalyst according to the first or second aspect in the presence of carbon dioxide.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.

The catalyst component for the ethylbenzene dehydrogenation reaction in the coexistence of carbon dioxide of the present invention is characterized by containing iron oxide, aluminum oxide and cerium oxide as essential components.

The catalyst of the present invention is used in the ethylbenzene dehydrogenation reaction in the coexistence of carbon dioxide as described in Patent No. 3032.
It exhibits even better performance than the catalyst of the invention described in Japanese Patent No. 816. This is due to the action of the newly added cerium oxide. Although the content of the action of cerium oxide is not completely clear, the cerium oxide in cerium oxide can easily move between tetravalent and trivalent, so that the surface of the catalyst during the reaction can be It is speculated that it can be kept active. Even if lanthanum oxide, which is one of rare earth elements similar to cerium, is added, the catalyst performance is not improved because the valence of lanthanum in lanthanum oxide remains trivalent (Comparative Example 4 below). reference).

The proportion of each catalyst component is not particularly limited, but when the total amount of the catalyst is 100% by weight, iron oxide is 5 to 5.
20% by weight, 65 to 94% by weight of aluminum oxide, and 1 to 15% by weight of cerium oxide. In such a quantitative range, the catalyst performance suitable for the reaction conditions can be obtained by appropriately determining the composition according to the reaction conditions. Further, the catalyst for dehydrogenation reaction of the present invention, iron oxide,
Aluminum oxide and cerium oxide are essential components, but other substances may be included as long as the reaction of the present invention is not impaired. Examples of such substances include calcium oxide, magnesium oxide, manganese oxide, silicon oxide, lanthanum oxide, and yttrium oxide.

As a raw material of iron oxide, aluminum oxide and cerium oxide which are the catalyst components of the present invention, respective nitrates, hydrochlorides, lead sulfates, organic acid salts, hydroxides and the like can be used. The catalyst is coprecipitation method, impregnation method, mixing method,
It can be produced by preparing a catalyst precursor by a method such as a sequential precipitation method, an alkoxide method, or a combination of these methods, and then calcining the catalyst precursor in air. The firing temperature of the catalyst precursor is not particularly limited, but is preferably in the range of 300 to 1000 ° C., 60
0-800 degreeC is especially preferable.

The catalyst thus produced is used as it is or after being granulated or tablet-molded by an appropriate method. The particle size and shape of the catalyst can be arbitrarily selected depending on the reaction system and the shape of the reactor. That is, the catalyst according to the present invention can be used in any reaction system such as fixed bed or fluidized bed.

The reaction conditions for producing styrene by the dehydrogenation reaction of ethylbenzene using the catalyst of the present invention are the same as those described in Japanese Patent No. 3032816, but the ratio of carbon dioxide to ethylbenzene is the same. Is 0.1 to 100 per mol of ethylbenzene.
Mol, preferably 1 to 50 mol, reaction temperature is 500 to 6
The temperature is in the range of 50 ° C., preferably 530 to 630 ° C., and the reaction pressure may be increased pressure, normal pressure or reduced pressure, and is preferably 0.2 to 1.5 atm (absolute pressure). Further, the catalyst of the present invention, when the activity decreases after a certain period of use,
The performance can be restored by firing again in air.

[0013]

EXAMPLES Hereinafter, the features of the present invention will be further clarified by giving examples.

Example 1 8.3 g of iron nitrate nonahydrate, aluminum nitrate nonahydrate 1
02.9 g and 2.2 g of cerium nitrate hexahydrate were dissolved in distilled water to prepare a 300 ml aqueous solution, which was designated as solution A. On the other hand, 52.5 g of anhydrous sodium carbonate was dissolved in distilled water,
A 300 ml aqueous solution was prepared and designated as solution B. Solution A and solution B were well stirred at a rate of 8 ml / min, respectively.
A precipitate was obtained by simultaneously dropping into 00 ml of room temperature distilled water. The precipitate was aged at room temperature for 1 day, filtered,
Washing was performed to remove sodium in the precipitate. After that, the precipitate is dried at 110 ° C. and dried in air at 750 ° C. for 2 hours.
Burned for hours. Next, the calcined oxide was compression-molded, crushed, and the particle size was adjusted to 250 to 600 μm to obtain a catalyst. The composition of this catalyst is as follows: iron oxide 10% by weight, aluminum oxide 85% by weight, cerium oxide (CeO ₂ ) 5% by weight.
Met.

0.4 g of the obtained catalyst was filled in a reaction tube,
After the temperature was raised to the reaction temperature in carbon dioxide, a mixed gas consisting of 10% by volume of ethylbenzene vapor and 90% by volume of carbon dioxide was passed through the catalyst layer, the pressure was 0.1 MPa, the mixed gas flow rate was 68 ml / min, and the temperature was 550. The mixed gas was reacted under the condition of ° C. The liquid component obtained by cooling the reaction product gas at -1 ° C was analyzed by gas chromatography. As a result, the styrene yield was 20% and the styrene selectivity was 97% after the reaction elapsed time of 6 hours (see Table 1).

Example 2 8.1 g of iron nitrate nonahydrate, aluminum nitrate nonahydrate 1
04.2 g and 0.9 g of cerium nitrate hexahydrate were dissolved in distilled water to prepare a 300 ml aqueous solution, which was designated as solution A. On the other hand, 52.5 g of anhydrous sodium carbonate was dissolved in distilled water,
A 300 ml aqueous solution was prepared and designated as solution B. Solution A and solution B were well stirred at a rate of 8 ml / min, respectively.
A precipitate was obtained by simultaneously dropping into 00 ml of room temperature distilled water. The precipitate was aged at room temperature for 1 day, filtered,
Washing was performed to remove sodium in the precipitate. After that, the precipitate is dried at 110 ° C. and dried in air at 750 ° C. for 2 hours.
Burned for hours. Next, the calcined oxide was compression-molded, crushed, and the particle size was adjusted to 250 to 600 μm to obtain a catalyst. The composition of this catalyst is as follows: iron oxide 10% by weight, aluminum oxide 88% by weight, cerium oxide (CeO ₂ ) 2% by weight.
Met.

0.4 g of the obtained catalyst was filled in a reaction tube,
The same dehydrogenation reaction of ethylbenzene as in Example 1 was performed. As a result, the styrene yield was 14% and the styrene selectivity was 97% after the reaction elapsed time of 6 hours (see Table 1).

Example 3 8.6 g of iron nitrate nonahydrate, aluminum nitrate nonahydrate 1
00.6 g and 4.5 g of cerium nitrate hexahydrate were dissolved in distilled water to prepare a 300 ml aqueous solution, which was designated as solution A. On the other hand, 52.5 g of anhydrous sodium carbonate was dissolved in distilled water,
A 300 ml aqueous solution was prepared and designated as solution B. Solution A and solution B were well stirred at a rate of 8 ml / min, respectively.
A precipitate was obtained by simultaneously dropping into 00 ml of room temperature distilled water. The precipitate was aged at room temperature for 1 day, filtered,
Washing was performed to remove sodium in the precipitate. After that, the precipitate is dried at 110 ° C. and dried in air at 750 ° C. for 2 hours.
Burned for hours. Next, the calcined oxide was compression-molded, crushed, and the particle size was adjusted to 250 to 600 μm to obtain a catalyst. The composition of this catalyst was 10% by weight of iron oxide, 80% by weight of aluminum oxide, and 10% by weight of cerium oxide (CeO ₂ ).

0.4 g of the obtained catalyst was filled in a reaction tube,
The same dehydrogenation reaction of ethylbenzene as in Example 1 was performed. As a result, the styrene yield was 18% and the styrene selectivity was 97% after the reaction elapsed time of 6 hours (see Table 1).

Comparative Example 1 110.7 g of aluminum nitrate nonahydrate and 2.1 g of cerium nitrate hexahydrate were dissolved in distilled water to prepare a 300 ml aqueous solution, which was used as solution A. On the other hand, anhydrous sodium carbonate 5
2.5 g was dissolved in distilled water to prepare a 300 ml aqueous solution, which was designated as solution B. 8 ml each of solution A and solution B
A precipitate was obtained by simultaneously dropping it into 800 ml of room temperature distilled water that was well stirred at a speed of 1 / min. The precipitate was aged at room temperature for 1 day, filtered and washed to remove sodium from the precipitate. Then, the precipitate was dried at 110 ° C. and calcined in air at 750 ° C. for 2 hours. Next, the oxide after firing is compression molded and then crushed to 250 to 600 μm.
The particle size was adjusted to a catalyst. The composition of this catalyst was 95% by weight of aluminum oxide and 5% by weight of cerium oxide.

0.4 g of the obtained catalyst was filled in a reaction tube,
The same dehydrogenation reaction of ethylbenzene as in Example 1 was performed. As a result, the styrene yield was 1% and the styrene selectivity was 82% after the reaction elapsed time of 6 hours (see Table 1). From this result, the catalyst composed of aluminum oxide and cerium oxide shows almost no activity, and the cerium oxide in the catalyst of the present invention to which cerium oxide is added plays a role of enhancing the performance of the catalyst composed of iron oxide and aluminum oxide. I understand.

Comparative Example 2 8.1 g of iron nitrate nonahydrate, aluminum nitrate nonahydrate 9
9.7 g was dissolved in distilled water to prepare a 300 ml aqueous solution, which was designated as solution A. On the other hand, anhydrous sodium carbonate 51.6g
Was dissolved in distilled water to prepare a 300 ml aqueous solution, which was designated as solution B. The liquids A and B were simultaneously added dropwise to 800 ml of room temperature distilled water, which was well stirred at a rate of 8 ml / min, to obtain precipitates. The precipitate was aged at room temperature for 1 day, filtered and washed to remove sodium from the precipitate. Then, the precipitate was dried at 110 ° C. and calcined in air at 750 ° C. for 2 hours. Next, the calcined oxide was compression-molded, crushed, and the particle size was adjusted to 250 to 600 μm to obtain a catalyst. The composition of this catalyst was 10% by weight of iron oxide and 90% by weight of aluminum oxide.

0.4 g of the obtained catalyst was filled in a reaction tube,
The same dehydrogenation reaction of ethylbenzene as in Example 1 was performed. As a result, the styrene yield was 11% and the styrene selectivity was 96% after the reaction elapsed time of 6 hours (see Table 1). From this result, it can be seen that the catalyst to which cerium oxide is not added has lower catalytic activity than the catalyst of the present invention to which cerium oxide is added.

Comparative Example 3 Iron nitrate nonahydrate 8.1 g, Aluminum nitrate nonahydrate 9
9.7 g and calcium nitrate tetrahydrate (3.4 g) were dissolved in distilled water to prepare a 300 ml aqueous solution, which was designated as solution A. On the other hand, 51.6 g of anhydrous sodium carbonate was dissolved in distilled water,
A 300 ml aqueous solution was prepared and designated as solution B. Solution A and solution B were well stirred at a rate of 8 ml / min, respectively.
A precipitate was obtained by simultaneously dropping into 00 ml of room temperature distilled water. The precipitate was aged at room temperature for 1 day, filtered,
Washing was performed to remove sodium in the precipitate. After that, the precipitate is dried at 110 ° C. and dried in air at 750 ° C. for 2 hours.
Burned for hours. Next, the calcined oxide was compression-molded, crushed, and the particle size was adjusted to 250 to 600 μm to obtain a catalyst. The composition of this catalyst was 10% by weight of iron oxide, 85% by weight of aluminum oxide, and 5% by weight of calcium oxide.

0.4 g of the obtained catalyst was filled in a reaction tube,
The same dehydrogenation reaction of ethylbenzene as in Example 1 was performed. As a result, the styrene yield was 13% and the styrene selectivity was 97% after the reaction elapsed time of 6 hours (see Table 1). From these results, it is understood that the catalyst to which calcium oxide is added (catalyst of the present invention) has lower catalytic activity than the catalyst of the present invention to which cerium oxide is added.

Comparative Example 4 8.3 g of iron nitrate nonahydrate, aluminum nitrate nonahydrate 1
02.9 g and lanthanum nitrate hexahydrate 2.2 g were dissolved in distilled water to prepare 300 ml of an aqueous solution, which was designated as solution A. On the other hand, 51.6 g of anhydrous sodium carbonate was dissolved in distilled water,
A 300 ml aqueous solution was prepared and designated as solution B. Solution A and solution B were well stirred at a rate of 8 ml / min, respectively.
A precipitate was obtained by simultaneously dropping into 00 ml of room temperature distilled water. The precipitate was aged at room temperature for 1 day, filtered,
Washing was performed to remove sodium in the precipitate. After that, the precipitate is dried at 110 ° C. and dried in air at 750 ° C. for 2 hours.
Burned for hours. Next, the calcined oxide was compression-molded, crushed, and the particle size was adjusted to 250 to 600 μm to obtain a catalyst. The composition of this catalyst was 10% by weight of iron oxide, 85% by weight of aluminum oxide, and 5% by weight of lanthanum oxide.

0.4 g of the obtained catalyst was filled in a reaction tube,
The same dehydrogenation reaction of ethylbenzene as in Example 1 was performed. As a result, the styrene yield was 12% and the styrene selectivity was 97% after the reaction elapsed time of 6 hours (see Table 1). From this result, the catalyst to which lanthanum oxide was added was
It can be seen that the catalytic activity is lower than that of the catalyst of the present invention to which cerium oxide is added.

Comparative Example 5 8.3 g of iron nitrate nonahydrate, aluminum nitrate nonahydrate 1
02.3 g, zirconium oxynitrate dihydrate 1.8 g
Was dissolved in distilled water to prepare 300 ml of an aqueous solution, which was designated as solution A. On the other hand, anhydrous sodium carbonate (52.1 g) was dissolved in distilled water to prepare an aqueous solution (300 ml), which was used as solution B.
The liquids A and B were simultaneously added dropwise to 800 ml of room temperature distilled water, which was well stirred at a rate of 8 ml / min, to obtain precipitates. The precipitate was aged at room temperature for 1 day, filtered and washed to remove sodium from the precipitate. Then, the precipitate is dried at 110 ° C. and dried in air at 75 ° C.
It was calcined at 0 ° C. for 2 hours. Next, the calcined oxide was compression-molded, crushed, and the particle size was adjusted to 250 to 600 μm to obtain a catalyst. The composition of this catalyst was 10% by weight of iron oxide, 85% by weight of aluminum oxide and 5% by weight of zirconium oxide.

0.4 g of the obtained catalyst was filled in a reaction tube,
The same dehydrogenation reaction of ethylbenzene as in Example 1 was performed. As a result, the styrene yield was 10% and the styrene selectivity was 97% after the reaction elapsed time of 6 hours (see Table 1). From these results, it can be seen that the catalyst containing zirconium oxide has a lower catalytic activity than the catalyst containing cerium oxide according to the present invention.

Comparative Example 6 8.2 g of iron nitrate nonahydrate, aluminum nitrate nonahydrate 1
01.2 g and zinc nitrate hexahydrate 3.0 g were dissolved in distilled water to prepare 300 ml of an aqueous solution, which was designated as solution A. on the other hand,
Dissolve 51.9 g of anhydrous sodium carbonate in distilled water to give 30
A 0 ml aqueous solution was prepared and designated as solution B. Solution A and solution B were well stirred at a rate of 8 ml / min, respectively, 800
A precipitate was obtained by simultaneously dropping into ml of distilled water at room temperature.
The precipitate was aged at room temperature for 1 day, filtered and washed to remove sodium from the precipitate. Then, the precipitate was dried at 110 ° C. and calcined in air at 750 ° C. for 2 hours. Next, the oxide after firing is compression molded and then crushed,
The particle size was adjusted to 250 to 600 μm to obtain a catalyst. The composition of this catalyst is 10% by weight of iron oxide and 8% of aluminum oxide.
It was 5% by weight and 5% by weight of zinc oxide.

0.4 g of the obtained catalyst was filled in a reaction tube,
The same dehydrogenation reaction of ethylbenzene as in Example 1 was performed. As a result, the styrene yield was 9% and the styrene selectivity was 97% after the reaction elapsed time of 6 hours (see Table 1). From this result, it is understood that the catalyst added with zinc oxide has lower catalytic activity than the catalyst of the present invention added with cerium oxide.

Comparative Example 7 8.2 g of iron nitrate nonahydrate, aluminum nitrate nonahydrate 1
01.6 g and gallium nitrate hydrate 2.9 g were dissolved in distilled water to prepare 300 ml of an aqueous solution, which was designated as solution A. On the other hand, 51.6 g of anhydrous sodium carbonate was dissolved in distilled water,
A 300 ml aqueous solution was prepared and designated as solution B. Solution A and solution B were well stirred at a rate of 8 ml / min, respectively.
A precipitate was obtained by simultaneously dropping into 00 ml of room temperature distilled water. The precipitate was aged at room temperature for 1 day, filtered,
Washing was performed to remove sodium in the precipitate. After that, the precipitate is dried at 110 ° C. and dried in air at 750 ° C. for 2 hours.
Burned for hours. Next, the calcined oxide was compression-molded, crushed, and the particle size was adjusted to 250 to 600 μm to obtain a catalyst. The composition of this catalyst was 10% by weight of iron oxide, 85% by weight of aluminum oxide, and 5% by weight of gallium oxide.

0.4 g of the obtained catalyst was filled in a reaction tube,
The same dehydrogenation reaction of ethylbenzene as in Example 1 was performed. As a result, the styrene yield was 8% and the styrene selectivity was 97% after the reaction elapsed time of 6 hours (see Table 1). From this result, the catalyst to which gallium oxide was added was
It can be seen that the catalytic activity is lower than that of the catalyst of the present invention to which cerium oxide is added.

Comparative Example 8 8.4 g of iron nitrate nonahydrate, aluminum nitrate nonahydrate 1
03.4 g and bismuth nitrate pentahydrate 1.7 g were dissolved in distilled water to prepare 300 ml of an aqueous solution, which was designated as solution A. On the other hand, 52.5 g of anhydrous sodium carbonate was dissolved in distilled water,
A 300 ml aqueous solution was prepared and designated as solution B. Solution A and solution B were well stirred at a rate of 8 ml / min, respectively.
A precipitate was obtained by simultaneously dropping into 00 ml of room temperature distilled water. The precipitate was aged at room temperature for 1 day, filtered,
Washing was performed to remove sodium in the precipitate. After that, the precipitate is dried at 110 ° C. and dried in air at 750 ° C. for 2 hours.
Burned for hours. Next, the calcined oxide was compression-molded, crushed, and the particle size was adjusted to 250 to 600 μm to obtain a catalyst. The composition of this catalyst was 10% by weight of iron oxide, 85% by weight of aluminum oxide, and 5% by weight of bismuth oxide.

0.4 g of the obtained catalyst was filled in a reaction tube,
The same dehydrogenation reaction of ethylbenzene as in Example 1 was performed. As a result, the styrene yield was 12% and the styrene selectivity was 97% after the reaction elapsed time of 6 hours (see Table 1). From this result, the catalyst to which lanthanum oxide was added was
It can be seen that the catalytic activity is lower than that of the catalyst of the present invention to which cerium oxide is added.

Comparative Example 9 Iron nitrate nonahydrate 8.3 g, aluminum nitrate nonahydrate 1
Dissolve 02.8 g and barium nitrate 1.4 g in distilled water,
A 300 ml aqueous solution was prepared and designated as solution A. On the other hand, 51.5 g of anhydrous sodium carbonate was dissolved in distilled water to obtain 300 m
An aqueous solution of 1 was prepared and designated as solution B. Liquid A and liquid B
800 ml well stirred at a rate of 8 ml / min each
At the same time, it was added dropwise to distilled water at room temperature to obtain a precipitate. The precipitate was aged at room temperature for 1 day, filtered and washed to remove sodium from the precipitate. Then, the precipitate was dried at 110 ° C. and calcined in air at 750 ° C. for 2 hours. Next, the oxide after firing is compression-molded and crushed to obtain 25
The particle size was adjusted to 0 to 600 μm to obtain a catalyst. The composition of this catalyst was 10% by weight of iron oxide, 85% by weight of aluminum oxide, and 5% by weight of barium oxide.

0.4 g of the obtained catalyst was filled in a reaction tube,
The same dehydrogenation reaction of ethylbenzene as in Example 1 was performed. As a result, the styrene yield was 10% and the styrene selectivity was 97% after the reaction elapsed time of 6 hours (see Table 1). From this result, the catalyst with barium oxide added was
It can be seen that the catalytic activity is lower than that of the catalyst of the present invention to which cerium oxide is added.

Comparative Example 10 8.2 g of iron nitrate nonahydrate, aluminum nitrate nonahydrate 1
01.4 g and 2.7 g of manganese nitrate hexahydrate were dissolved in distilled water to prepare a 300 ml aqueous solution, which was designated as solution A. On the other hand, 51.9 g of anhydrous sodium carbonate was dissolved in distilled water,
A 300 ml aqueous solution was prepared and designated as solution B. Solution A and solution B were well stirred at a rate of 8 ml / min, respectively.
A precipitate was obtained by simultaneously dropping into 00 ml of room temperature distilled water. The precipitate was aged at room temperature for 1 day, filtered,
Washing was performed to remove sodium in the precipitate. After that, the precipitate is dried at 110 ° C. and dried in air at 750 ° C. for 2 hours.
Burned for hours. Next, the calcined oxide was compression-molded, crushed, and the particle size was adjusted to 250 to 600 μm to obtain a catalyst. The composition of this catalyst was 10% by weight of iron oxide, 85% by weight of aluminum oxide, and 5% by weight of manganese oxide.

0.4 g of the obtained catalyst was filled in a reaction tube,
The same dehydrogenation reaction of ethylbenzene as in Example 1 was performed. As a result, the styrene yield was 13% and the styrene selectivity was 97% after the reaction elapsed time of 6 hours (see Table 1). From this result, the catalyst added with manganese oxide,
It can be seen that the catalytic activity is lower than that of the catalyst of the present invention to which cerium oxide is added.

[0040]

[Table 1]

[0041]

INDUSTRIAL APPLICABILITY The catalyst of the present invention exhibits extremely high catalytic activity for a long time in the dehydrogenation reaction of ethylbenzene in the presence of carbon dioxide and does not decrease.
Therefore, the styrene monomer can be produced industrially advantageously.

[Procedure amendment]

[Submission date] July 23, 2002 (2002.7.2)
3)

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0005

[Correction method] Change

[Correction content]

That is, according to the present invention, firstly, iron oxide,
Provided is a catalyst containing aluminum oxide and cerium oxide as essential components and showing high performance in an ethylbenzene dehydrogenation reaction in the presence of carbon dioxide. Secondly, in the first invention, a catalyst containing iron oxide, aluminum oxide and cerium oxide as essential components, wherein the whole catalyst is 1
When it is set to 00% by weight, the content of each oxide is 5 to 20% by weight, 65 to 94% by weight , and 1 to 15 % by weight in the above order.
A catalyst for ethylbenzene dehydrogenation reaction in the presence of carbon dioxide is provided. Thirdly, there is provided a method for producing a styrene monomer, which comprises contacting ethylbenzene with the catalyst according to the first or second aspect in the presence of carbon dioxide.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hitoshi Inaba             1-1-1 Higashi 1-1-1 Tsukuba City, Ibaraki Prefecture             Inside the Tsukuba Center, National Institute of Advanced Industrial Science and Technology F-term (reference) 4G069 AA03 BA01A BA01B BB04A                       BB04B BC43A BC43B BC66A                       BC66B CB18 EA02Y EB18Y                       FC08                 4H006 AA02 AC12 BA08 BA09 BA19                       BA30 BC10 BC11 BC18 BE41                 4H039 CA21 CC10

Claims (3)

[Claims] 1. A catalyst for an ethylbenzene dehydrogenation reaction in the presence of carbon dioxide, which comprises iron oxide, aluminum oxide and cerium oxide as essential components. 2. A catalyst composed of a metal oxide containing iron oxide, aluminum oxide and cerium oxide as essential components, wherein the content of each oxide is the above when the total catalyst is 100% by weight. The catalyst for ethylbenzene dehydrogenation reaction in the coexistence of carbon dioxide according to claim 1, which is 5 to 20% by weight, 65 to 94% by weight, and 1 to 15% by weight in order. 3. A method for producing a styrene monomer, which comprises contacting ethylbenzene with the catalyst according to claim 1 or 2 in the presence of carbon dioxide.