JP2713684B2 - Methanol synthesis method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for synthesizing methanol by hydrogenating carbon dioxide in a solvent in the presence of a catalyst.

[0002]

2. Description of the Related Art Conventionally, methanol is produced from a synthesis gas (mixed gas of carbon monoxide and hydrogen) as a raw material by a gas-phase process using a copper-zinc catalyst at 250-350 ° C., 50-1
It is industrially synthesized under the conditions of 50 atm and is mainly used as a chemical raw material. However, in the conventional gas phase process, it is difficult to efficiently remove the heat of reaction, so that a large amount of unreacted gas can be recycled by reducing the reaction conversion rate per pass,
Although efforts have been made to improve energy efficiency and various measures have been taken, it has become more difficult than ever to increase the size of a plant or to dramatically improve energy efficiency.

For this reason, it has been studied to use a liquid phase process to efficiently remove heat of reaction with a solvent having a large heat capacity to increase the size of the process and improve energy efficiency. As an example of such a liquid phase process, 250
A Chem System process for synthesis at 50 to 100 atm and a BNL process of Brookhaven National Laboratory in the United States for synthesis at lower temperature (100 ° C) have been proposed.

On the other hand, a methanol synthesis method using carbon dioxide as a raw material (CO ₂ + 3H ₂ → CH ₃ OH + H ₂ O) has recently been receiving attention from the viewpoint of recycling and recycling of carbon resources and solving global environmental problems. At this time, the reaction produces the target component methanol and at the same time produces equimolar water, but in the liquid phase process, the presence of this water is
If the catalyst disturbs the thermodynamic equilibrium, or if a homogeneous catalyst used in the BNL process is used in this reaction, water will cause poisoning, and sufficient reaction activity of the catalyst will be obtained. And methanol was not produced in high yield.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for producing methanol by a catalytic hydrogenation reaction in a liquid phase process using carbon dioxide as a raw material and obtaining a high methanol yield using a highly active catalyst. It is to provide a method.

[0006]

According to the present invention, there is provided a method for synthesizing methanol by a catalytic hydrogenation reaction using a liquid phase process using carbon dioxide as a raw material, wherein carbon dioxide and hydrogen are mixed in a hydrophilic solvent. A method is provided that comprises contacting with a suspended catalyst.

As the hydrophilic solvent to be used, a hydrophilic organic solvent having a high polarity is suitable. For example, alcohols such as ethylene glycol can easily be used even at about 200 ° C. which is a suitable temperature for carrying out the present invention. In order to cause thermal decomposition, it is preferable to use hydrophilic ethers.
Examples of such preferred ethers include diethylene glycol diethyl ether, diethylene glycol dimethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol monomethyl ether, isoamyl ether, phenyl ether, benzyl ether, tetrahydrofuran, dioxane, and the like. Particularly, diethylene glycol dimethyl ether, tetrahydrofuran and dioxane are preferred.

The catalyst used in the present invention is preferably a catalyst containing copper and / or copper oxide and zinc oxide, and a catalyst containing at least one of zirconium oxide and aluminum oxide together with copper and / or copper oxide and zinc oxide. The content of copper and / or copper oxide is 30 to
It is appropriate that the content of zinc oxide is 70% by weight and the content of zinc oxide is 5 to 65% by weight. The content of zirconium oxide and / or aluminum oxide is suitably from 5 to 65% by weight. The best catalyst performance can be obtained by determining appropriate amounts of these contents depending on conditions such as the composition of the reaction raw material gas, the reaction temperature, and the reaction pressure.

The method for preparing the catalyst may be any of the conventionally known coprecipitation method, ammonia gas precipitation method or impregnation method using the salt of each catalyst component as a starting material.
After being prepared by these methods, 300 to 600 in air
Firing at 0 ° C. to form an oxide. If not calcined or calcined at a temperature exceeding 600 ° C., the catalyst performance tends to decrease.

When this catalyst is used in the methanol synthesis reaction of the present invention, it may be used as it is or may be used after previously treating the catalyst with hydrogen to reduce the copper oxide component in the catalyst. In short, this catalyst may be used in a state in which the catalyst is finely ground, suspended and dispersed in the hydrophilic solvent and allowed to react while being brought into contact with the reaction gas,
Regarding the method of contacting with the reaction gas, the reaction gas may be put in a reaction vessel in advance and may be carried out in a batch system, or may be carried out by a flow system in which the reaction gas is continuously supplied from outside the system into the reaction vessel. However, in order to carry out the reaction in a batch mode, the catalyst suspended in a hydrophilic solvent is preferably used at 100 rpm to improve the dispersion of the catalyst and to ensure sufficient contact between the catalyst and the reaction gas. Above, particularly preferably 300 rpm
The reaction is carried out while keeping the stirring at least m.

As the catalyst, a catalyst molded by a known method may be used. The particle size and shape of the catalyst can be arbitrarily selected depending on the type of reaction and the shape of the reactor.
It is preferable to use it after pulverizing it to 0 mesh or less.

In the synthesis of methanol by the reaction, the reaction temperature is preferably 100 to 350 ° C., particularly preferably 15 to obtain high yield of methanol.
0-250 ° C. The higher the reaction pressure, the better, but 20
The pressure is preferably at least atmospheric pressure. The mixing ratio of hydrogen and carbon dioxide used as a raw material can take any value, but the molar ratio of hydrogen / carbon dioxide is preferably 2 or more. In addition, it is preferable that the reaction time at the time of performing the reaction in the batch mode be 10 minutes or more.

[0013]

The present invention will be described in more detail with reference to the following examples.

Example 1 Copper nitrate trihydrate 61.2 g, zinc nitrate hexahydrate 44.3
g and 26.2 g of zirconium oxynitrate in distilled water
After dissolution, 500 ml of an aqueous solution was prepared and used as solution A. Ma
Separately, 254.2 g of sodium carbonate decahydrate was added to distilled water.
To prepare a 500 ml aqueous solution, which was designated as solution B. Intense
Solution A and Solution B are mixed in 200 ml of distilled water
At a rate of 5 ml / min to form a precipitate. Profit
The precipitate obtained is washed with distilled water, dried at 110 ° C.
It was calcined at 00 ° C. in air for 2 hours. Composition of this catalyst
Are CuO 43.6 wt%, ZnO 26.1 wt%, Z
rO_TwoIt was 26.1% by weight. 1 g of this catalyst and
Ethylene glycol dimethyl ether 50ml is auto
After sealing in a clave, the air inside is pumped by a vacuum pump.
To eliminate CO_Two 25% by volume and H_Two 75% by volume mixed gas
About 60kg / cm ^Two G was applied. Stirring speed 46
The reaction was performed by raising the temperature to 200 ° C. while stirring at 5 rpm.
Was. After a reaction time of 5 hours, the reaction product gas and the solvent
Use products such as methanol and water by gas chromatography
Analysis_Two Conversion and methanol selection
The selectivity was as shown in Table 1. In addition, other generation
The main products are CO, methane and dimethyl ether.
Only trace amounts of methyl formate were produced.

Example 2 Copper nitrate trihydrate 48.0 g, zinc nitrate hexahydrate 34.7
g and 69.4 g of aluminum nitrate nonahydrate were dissolved in distilled water to prepare 500 ml of an aqueous solution, which was used as solution A. Separately, 267.9 g of sodium carbonate decahydrate was dissolved in distilled water to prepare a 500 ml aqueous solution, which was used as solution B. The solution A and the solution B were dropped at a rate of 5 ml / min into 200 ml of distilled water which was vigorously stirred to form a precipitate. The obtained precipitate is washed with distilled water, dried at 110 ° C.,
It was calcined at 00 ° C. in air for 2 hours. The composition of this catalyst was 43.6 wt% of CuO, 26.1 wt% of ZnO,
l ₂ O _{3 was} 26.1% by weight. A reaction was carried out in the same manner as in Example 1 using this catalyst. When the products such as methanol and water in the reaction product gas and the solvent were analyzed using a gas chromatograph, the CO ₂ conversion and the methanol selectivity were as shown in Table 1. The other products were mainly CO, and only trace amounts of methane, dimethyl ether and methyl formate were formed.

Example 3 1 g of catalyst prepared in the same manner as in Example 1 and dioxane 5
When the same reaction as in Example 1 was performed using 0 ml,
The results shown in Table 1 were obtained.

Comparative Example 1 1 g of the catalyst prepared in the same manner as in Example 2 and a mineral oil (trade name: Smoyl 4) which is a solvent (hydrophobic solvent) that does not dissolve water at all
0) and the same reaction as in Example 1 was performed, and the results shown in Table 2 were obtained.

Comparative Example 2 Example 1 was carried out using 1 g of the catalyst prepared in the same manner as in Example 2 and decalin which is a solvent (hydrophobic solvent) that does not dissolve water at all.
When the same reaction was carried out, the results shown in Table 2 were obtained.

[0019]

[Table 1]

[0020]

[Table 2]

 ──────────────────────────────────────────────────続 き Continuing on the front page (73) Patent holder 000156961 Kansai Thermochemical Co., Ltd. 2--23 Ohama-cho, Amagasaki-shi, Hyogo (73) Patent holder 000183303 Sumitomo Metal Mining Co., Ltd. 5--11 Shimbashi, Minato-ku, Tokyo, Japan No. 3 (73) Patent holder 000001199 Kobe Steel, Ltd. 1-318, Wakihama-cho, Chuo-ku, Kobe-shi, Hyogo (73) Patent holder 000000284 Osaka Gas Co., Ltd. 4-1-1, Hirano-cho, Chuo-ku, Osaka-shi, Osaka No. 2 (74) The above seven agents Patent Attorney Tadashi Wakabayashi (72) Inventor Daiki Watanabe 2-8-11 Nishi-Shimbashi, Minato-ku, Tokyo 7th Toyo Maritime Building 8th floor (72) Inventor Kawai Kiyoshi 2-8-11 Nishi-Shimbashi, Minato-ku, Tokyo 7th Oriental Maritime Building 8F Inside the Research Institute of Innovative Technology for the Earth (72) Inventor Masami Takeuchi Higashi 8th floor of the 7th Toyo Maritime Building, 2-8-11 Nishi-Shimbashi, Minato-ku, Japan (72) Inventor Yuki Kanai 2-8-11 Nishi-Shimbashi, Minato-ku, Tokyo 7th Toyo Maritime Building 8 (72) Inventor Keiko Moriya 2-8-11 Nishi-Shimbashi, Minato-ku, Tokyo 7th Toyo Maritime Building 8th Floor Inside the Global Environmental Industry Research Institute (72) Inventor Corner Terumitsu Hon 2-8-11 Nishi-Shimbashi, Minato-ku, Tokyo 7th Oriental Maritime Building 8F Inside the Research Institute of Innovative Technology for the Earth (72) Inventor Masahiro Saito 16-3 Onogawa, Tsukuba, Ibaraki Pref. Examiner in the Research Institute Yoko Watanabe (56) References JP-A-3-258738 (JP, A)

Claims (5)

(57) [Claims] 1. A method for synthesizing methanol by a catalytic hydrogenation reaction using carbon dioxide as a raw material using a liquid phase process, wherein carbon dioxide and hydrogen are combined with diethylene glycol.
Diethyl ether, diethylene glycol dimethyl ether
-Tel, diethylene glycol monoethyl ether, di
Ethylene glycol monobutyl ether, diethylene glycol
Recall monomethyl ether, isoamyl ether,
Phenyl ether, benzyl ether, tetrahydrofura
A method for synthesizing methanol, comprising contacting a catalyst suspended in a hydrophilic solvent selected from the group consisting of benzene and dioxane . 2. The method for synthesizing methanol according to claim 1, wherein the catalyst contains copper and / or copper oxide and zinc oxide. 3. The method according to claim 2, wherein the catalyst further contains at least one of zirconium oxide and aluminum oxide. 4. The catalyst has a copper and / or copper oxide content of 30 to 70% by weight and a zinc oxide content of 5 to 65%.
3. The method for synthesizing methanol according to claim 2, wherein the amount is methanol. 5. The method according to claim 4, wherein the catalyst further contains at least one of zirconium oxide and aluminum oxide in an amount of 5 to 65% by weight.