JPH05170673A - Conversion of carbon dioxide with ethane - Google Patents

Abstract

PURPOSE:To convert a mixed gas of carbon dioxide and ethane into carbon monoxide useful as a raw material for organic chemical industry by bringing the mixed gas into contact with a chromium oxide catalyst. CONSTITUTION:A mixed gas (molar ratio of ethane/carbon dioxide is preferably 0.1-20) of carbon dioxide and ethane as a reducing agent is brought into contact with a chromium oxide catalyst (e.g. one obtained by immersing silica in an aqueous solution of chromium nitrate, drying and burning in an air flow) (at 300-1,000 deg.C under normal pressure to 20atm) to carry out the objective conversion.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process for co-producing carbon monoxide and ethylene, which are important as raw materials in the organic chemical industry.

[0002]

2. Description of the Related Art As carbon dioxide is a major causative substance of global warming, reduction of emission and effective use thereof are urgently required. On the other hand, carbon monoxide is a very important compound as a raw material when producing acetic acid from methanol, or as a raw material when producing various organic compounds by hydrophorylation. Therefore, if carbon dioxide can be used as a raw material and converted into useful carbon monoxide, environmental issues
It is also very industrially significant.

As a method for producing carbon monoxide by reducing carbon dioxide, a method using hydrogen as a reducing agent (US Pat. No. 3,718,418) and a method using methane (O. Tokunaga and S. Ogasawa) are available.
Ra, React. Kinet. Catal. Let
t. , 39 (1), 69 (1989)), a method using toluene (66th Symposium on Catalysis, (A) 3L407 (1)
990)) and the like are known.

[0004]

The object of the present invention is to reduce carbon dioxide to produce carbon monoxide.
It is to provide a new and economical method.

[0005]

[Means for Solving the Problems] In order to solve the above problems, the inventors of the present invention have diligently studied the conversion reaction of carbon dioxide into carbon monoxide, and as a result, surprisingly, ethane, which is a lower hydrocarbon, was selected. It was found that carbon dioxide can be efficiently and economically reduced to produce carbon monoxide by using it as a reducing agent, and at the same time, ethylene can be coproduced with good selectivity, and the present invention has been completed.

That is, the present invention relates to a method for converting carbon dioxide with ethane, which comprises contacting a mixed gas containing carbon dioxide and ethane with a chromium oxide catalyst to produce carbon monoxide and ethylene.

The present invention will be described in more detail below.

In the present invention, a chromium oxide catalyst is used as the catalyst. The chromium oxide catalyst may be chromium oxide itself or a catalyst in which chromium oxide is supported on a carrier.

The method for preparing the chromium oxide catalyst is not particularly limited, and may be obtained by calcining an inorganic salt such as nitrate or chloride as a raw material, or an inorganic compound such as silica, alumina, zirconia or titania is impregnated with the chromium salt. It may be obtained by firing.

It may also be prepared by a coprecipitation method or an alcoside method. For example, a chromium oxide catalyst can be obtained by impregnating silica with an aqueous solution of chromium nitrate, drying, and calcining in an air stream.

Alternatively, a catalyst can be prepared by adding aqueous ammonia or sodium carbonate to a mixed aqueous solution of chromium chloride and aluminum nitrate to obtain a precipitate, which is washed with water, dried and calcined.

The firing temperature used in the adjusting method is preferably 300 ° C. or higher. If the temperature is lower than 300 ° C, the chromium salt used as a raw material does not decompose, so that a sufficient carbon dioxide conversion rate may not be obtained.

In the method of the present invention, ethane is used as a carbon dioxide reducing agent, and the amount of ethane can be defined as the molar ratio of ethane to carbon dioxide. Specifically, the ethane / carbon dioxide ratio is 0.05 to
However, 0.1 to 20 is preferable.
When the ethane / carbon dioxide ratio is less than 0.05, the amount of carbon dioxide to be recycled increases, while when the ethane / carbon dioxide ratio exceeds 25, a sufficient carbon monoxide generation rate cannot be obtained, which is uneconomical. Sometimes.

In addition to ethane and carbon dioxide as a gas supplied into the reaction system, air, nitrogen or steam may be added as a diluting gas.

The reaction temperature in the method of the present invention is 300 ° C.
It may be up to 1000 ° C. More preferably 400 ° C to 950
℃. If the reaction temperature is lower than 300 ° C, a sufficient conversion rate of carbon dioxide cannot be obtained, and if it exceeds 1000 ° C, the activity may be decreased due to the sintering or coking of the catalyst, or the ethylene produced by the decomposition of ethylene may be decomposed. The yield may be reduced.

The reaction pressure is not particularly limited, and the reaction may be carried out at atmospheric pressure to 20 atm, preferably atmospheric pressure to 10 atm.

The feed rate of the raw material to the catalyst can be defined by the feed rate (SV) of the raw material per unit volume of the catalyst. In the method of the present invention, the SV is 500 to 1000.
00 / h is sufficient. If the SV is less than 500 / h, the carbon monoxide generation rate is low, and if the SV is more than 100,000 / h, the conversion rate of the raw material is lowered, which may be uneconomical.

The reaction method is not particularly limited as long as the catalyst and the raw materials can be efficiently contacted, and for example, the reaction can be carried out in a fixed bed, a fluidized bed or a moving bed.

The catalyst may be used by molding or may be used as a powder, and it may be molded into a desired size depending on the reaction method.

[0020]

EXAMPLES The present invention will be described below with reference to examples.
It goes without saying that the invention is not limited by these examples.

Example 1 6.0 g of chromium nitrate nonahydrate was dissolved in 20 cc of water, and then spherical silica having a diameter of 3 mm (manufactured by Fuji Devison, CAR) was used.
10.4 g of IACT-30) was added and impregnated. Then, after drying overnight at 110 ° C, the catalyst was dried at 600 ° C for 2 hours.
Air calcination was carried out for an hour to obtain a catalyst containing 10% by weight of chromium oxide.

1.5 g of this catalyst was added to SUS with an inner diameter of 14 mm.
Fill a reaction tube, keep the temperature at 700 ° C., and add 1: 1 of a mixed gas of nitrogen, carbon dioxide and ethane in a molar ratio of 3: 1: 1.
00 cc / min was supplied. The reaction gas was analyzed by gas chromatography. The reaction results are shown in Table 1.

Example 2 After dissolving 4.5 g of chromium nitrate nonahydrate in 10 cc of water, spherical alumina having a diameter of 3 mm (KHA-2 manufactured by Sumitomo Chemical Co., Ltd.)
4) 10.0 g was added and impregnated. Then overnight 11
After drying at 0 ° C., the catalyst was air-baked at 700 ° C. for 2 hours to obtain a catalyst containing 8% by weight of chromium oxide.

1.5 g of this catalyst was added to SUS having an inner diameter of 14 mm.
The reaction tube was filled and the same reaction as in Example 1 was performed. The reaction results are shown in Table 1.

Example 3 A predetermined amount of chromium nitrate nonahydrate (4.5 g) was dissolved in water (10 cc), and a zirconia extruded product (Norton) 1
0.0 g was added and impregnated. Then, the same treatment as in Example 2 was performed to obtain a catalyst containing 8% by weight of chromium oxide.

1.5 g of this catalyst was added to SUS with an inner diameter of 14 mm.
The reaction tube was filled and the same reaction as in Example 1 was performed. The reaction results are shown in Table 1.

Comparative Example 1 A catalyst containing 10% by weight of bismuth oxide was prepared by using the same amount of bismuth nitrate pentahydrate as a raw material and the same catalyst preparation method as in Example 1, and 1.5 g of this catalyst was added to SUS having an inner diameter of 14 mm. Fill a reaction tube and keep the temperature at 650 ° C., and add 1: 1 of a mixed gas of nitrogen, carbon dioxide and ethane in a molar ratio of 3: 1: 1.
00 cc / min was supplied. The reaction results are shown in Table 1.

Comparative Examples 2 to 4 Catalysts containing tin chloride dihydrate, lead nitrate and manganese nitrate hexahydrate as starting materials and carrying 10% by weight of oxide by the same catalyst preparation method as in Comparative Example 1 were prepared. Then, the same reaction as in Comparative Example 1 was performed. The reaction results are shown in Table 1.

[0029]

[Table 1]

[0030]

EFFECT OF THE INVENTION By using ethane as a carbon dioxide reducing agent and using a chromium oxide catalyst, carbon monoxide and ethylene can be co-produced economically.

[Procedure amendment]

[Submission date] January 20, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction content]

The firing temperature used in the above preparation method is preferably 300 ° C. or higher. If the temperature is lower than 300 ° C, the chromium salt used as a raw material does not decompose, so that a sufficient carbon dioxide conversion rate may not be obtained.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0021

[Correction method] Change

[Correction content]

Example 1 6.0 g of chromium nitrate nonahydrate was dissolved in 20 cc of water, and then spherical silica having a diameter of 3 mm (manufactured by Fuji Devison, CAR) was used.
10.4 g of IACT-30) was added, and it was made to immerse for 3 hours . Then, after drying overnight at 110 ° C., the catalyst was washed with 60
Air calcination was carried out at 0 ° C. for 2 hours to obtain a catalyst containing 10% by weight of chromium oxide.

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] 0023

[Correction method] Change

[Correction content]

Example 2 After dissolving 4.5 g of chromium nitrate nonahydrate in 10 cc of water, spherical alumina having a diameter of 3 mm (KHA-2 manufactured by Sumitomo Chemical Co., Ltd.)
4) 10.0 g was added and immersed for 3 hours . Then, after drying overnight at 110 ° C., the catalyst was air-calcined at 700 ° C. for 2 hours to obtain a catalyst containing 8% by weight of chromium oxide.

[Procedure amendment 4]

[Document name to be amended] Statement

[Name of item to be corrected] 0025

[Correction method] Change

[Correction content]

Example 3 A predetermined amount of chromium nitrate nonahydrate (4.5 g) was dissolved in water (10 cc), and a zirconia extruded product (Norton) 1
0.0g was added and it was made to immerse for 3 hours . Then, Example 2
The same treatment as above was performed to obtain a catalyst containing 8% by weight of chromium oxide.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tetsuo Asakawa 6-7-5, also known as Yokkaichi-shi, Mie (72) Inventor Sotaro Nakamura 6-19-18 Nagataasa-cho, Suzuka-shi, Mie

Claims (1)

[Claims] 1. A method for converting carbon dioxide with ethane, which comprises contacting a mixed gas of carbon dioxide and ethane with a chromium oxide catalyst to produce carbon monoxide and ethylene.