JP2813770B2 - Ethanol production method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing ethanol by catalytic hydrogenation of carbon dioxide. Ethanol is an important basic raw material for various chemicals, medicines and agricultural chemicals.

[0002]

2. Description of the Related Art At present, ethanol is produced by a fermentation method using yeast such as starch or molasses or a method of hydrating ethylene in the presence of an acidic catalyst or the like. In recent years, environmental problems such as global warming have become a problem, and in particular, the suppression of carbon dioxide emission, which is considered to be the main cause, has been studied. The most desirable solution is to collect and recycle this. is there. As one of the measures, there is a demand for the development of an industrial conversion technology for converting ethanol from carbon dioxide into carbon resources.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing industrially useful ethanol by effectively utilizing carbon dioxide as a carbon source from the above viewpoints.

[0004]

DISCLOSURE OF THE INVENTION The present inventors have previously described a method for producing ethanol by catalytic hydrogenation of carbon dioxide, which comprises (1) a catalyst comprising iron, copper, zinc, and potassium;
(2) Hydrogen of carbon dioxide in the presence of iron, copper, zinc, potassium, and a catalyst composed of Group VIII elements of the periodic table selected from cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium, and platinum It has been found that ethanol can be obtained in a high yield by carrying out the chlorination reaction, and a patent application has been filed (Japanese Patent Application No. 7-26797).
No. 4). However, the catalyst showed good results in the early stage of the reaction, but the activity decreased with the lapse of time of the reaction, and the catalyst life was insufficient. Therefore, the present inventors have further studied to improve the life of the catalyst, and as a result, it was found that the addition of chromium and / or silicon to the catalyst system of the above (1) and (2) significantly improved the life of the catalyst. And arrived at the present invention.

That is, the present invention comprises (1) iron, copper, zinc, potassium and chromium and / or silicon, wherein the atomic ratio of copper / iron, zinc / iron, potassium / iron, chromium or silicon / iron is respectively 0.2-3.0, 0.2-3.0, 0.0
A method for producing ethanol, comprising catalytically hydrogenating carbon dioxide using a catalyst of 1 to 0.5, 0.001 to 0.2, and (2) iron, copper, zinc, potassium, and cobalt. -Containing a Group VIII element of the periodic table selected from nickel, ruthenium, rhodium, palladium, osmium, iridium, and platinum, and chromium and / or silicon;
The atomic ratio of copper / iron, zinc / iron, potassium / iron, group VIII element of the periodic table / iron, chromium or silicon / iron is 0.2 to 3.0, 0.2 to 3.0, 0, respectively. .01-0.5,
This is a method for producing the ethanol using a catalyst of 0.00001-2, 0.001-0.2.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The ethanol synthesis reaction of the present invention is represented by the following formula. 2CO ₂ + 6H ₂ → C ₂ H ₅ OH + 3H ₂ O In preparing the catalyst of the present invention, iron, copper, zinc and potassium, chromium and / or silicon, or iron, copper, zinc, potassium and the periodic table It is only necessary that the Group VIII element and each component of chromium and / or silicon are finally combined, and there is no particular limitation on the compound form as a starting material of each element. Oxides, basic carbonates, nitrates, acetates, various complexes, and the like are used. The Group VIII element of the periodic table is cobalt nickel ruthenium rhodium palladium osmium iridium or platinum.

[0007] In the above components, the starting materials for iron and copper are generally used in the reaction after the prepared catalyst is reduced, so that an easily reducible compound or a compound that can be converted to an easily reducible compound is used. Preferably, it is used. The composition ratio of each component is such that the atomic ratios of copper / iron, zinc / iron, potassium / iron, group VIII element of the periodic table / iron, chromium or silicon / iron are 0.2 to 3.0 and 0. 0, respectively. 2-3.0, 0.
01-0.5, 0.00001-2, 0.001-0.
2. Iron, Copper, Zinc, Potassium and Periodic Table VI
If the group II element exceeds these ranges, the amount of ethanol produced decreases. When chromium and silicon exceed these ranges, the effect of improving the catalyst life is lost.

[0008] The method for preparing the catalyst in the present invention includes:
There is no particular limitation, but when it does not contain a Group VIII element of the periodic table, for example, a method of kneading and preparing a compound of iron, copper, zinc and potassium and chromium and / or silicon, iron, copper Prepared by impregnating or mixing a potassium compound, chromium and / or a silicon compound into a coprecipitate obtained by mixing a mixed solution of a compound of zinc and a compound with a precipitant, iron, copper and zinc, chromium and A method of impregnating or mixing a co-precipitate obtained by mixing a mixed solution of a compound of silicon and a precipitant with a potassium compound, mixing iron, copper and potassium with a compound of chromium and / or silicon A method of preparing a solution by supporting it on a suitable zinc compound, and supporting a mixed solution of copper, zinc and potassium and a compound of chromium and / or silicon on a suitable iron compound And the like.

As a method for preparing a catalyst containing a Group VIII element of the periodic table, for example, iron, copper, zinc, potassium and a Group VIII element of the periodic table and a compound of chromium and / or silicon are kneaded. Method of preparation, co-precipitation obtained by mixing a mixed solution of compounds of iron, copper and zinc and a precipitant, impregnating a group VIII element compound of the periodic table, a potassium compound, and a chromium and / or silicon compound Alternatively, a potassium compound, a chromium and / or a coprecipitate obtained by mixing a mixed solution of a compound of iron, copper, zinc and a compound of the group VIII element of the periodic table with a precipitant are mixed.
Or a method of impregnating or mixing with a silicon compound, prepared by supporting a mixed solution of iron, copper, potassium and a group VIII element of the periodic table with a compound of chromium and / or silicon on a suitable zinc compound how to. A method in which a mixed solution of copper, zinc, potassium and a group VIII element of the periodic table and a compound of chromium and / or silicon is supported on a suitable iron compound to prepare the mixed solution can be employed.

In the preparation of the catalyst according to the present invention, a substance (alumina, magnesia, titania, carbon, etc.) which does not adversely affect the reaction for the uniform dispersion or support of the essential components can be used. There is no particular limitation on the shape of the catalyst used in the reaction in the present invention, but it can be used in the form of powder, tablet molding, extrusion molding, or the like.

[0011] The catalyst precursor thus prepared is
After calcining, it is reduced with hydrogen and used as a catalyst in the reaction. The method of calcining the catalyst precursor is not particularly limited,
It is carried out by a method of firing while standing in a furnace, a method of firing in a gas stream, or the like, and a method of firing with an atmosphere gas mixed with air or an inert gas at an arbitrary ratio. Generally, the firing temperature is preferably in the range of 200 to 600 ° C, and the firing time is generally about 0.5 to 10 hours.

[0012] The hydrogen reduction treatment of the catalyst is performed in pure hydrogen or hydrogen diluted at an arbitrary ratio with an inert gas.
The treatment method is not particularly limited, but it is preferable to carry out the treatment while flowing the above-mentioned atmospheric gas in consideration of removal of generated water and the like. The reduction temperature is preferably in the range of 250 to 500C, and the reduction time is about 0.5 to 20 hours. Since the catalyst after hydrogen reduction is very easily oxidized, it is desirable to perform a hydrogen reduction treatment in the reactor immediately before use in the reaction.
The reduction of the catalyst can be performed not only with hydrogen but also with a mixed gas of hydrogen and carbon monoxide or carbon monoxide.

The catalytic hydrogenation reaction of carbon dioxide according to the present invention is not particularly limited as long as it is a reaction system using a solid catalyst, but a system such as a gas-phase fixed bed, a gas-phase fluidized bed, or a liquid-phase suspension bed is used. be able to. The raw materials used in the reaction of the present invention are:
A mixed gas containing carbon dioxide and hydrogen or further an inert gas is used. This mixed gas may contain carbon monoxide. The CO ₂ / H ₂ molar ratio in the mixed gas is desirably in the range of 0.1 to 10. The reaction temperature is in the range of 100 to 600C, preferably 200 to 400C. The reaction pressure is 2 to 300 atm, preferably 10 to
The range is 80 atm. Gas space velocity is 100-50
000 hr ^-1 , preferably 1000 to 30000 hr ^-1
Range. As a reaction product, in addition to ethanol as a main product, methanol, propanol, alcohols such as butanol, acetaldehyde, acetate esters, etc.
Hydrocarbons, carbon monoxide, etc. are produced. Liquid products such as ethanol can be separated and recovered by distillation or the like.

[0014]

The present invention will be specifically described below with reference to examples and comparative examples. However, the present invention is not limited to these embodiments.

Example 1 6.04 g of copper nitrate trihydrate, 7.44 of zinc nitrate hexahydrate
g, iron nitrate nonahydrate 30.30 g, and chromium nitrate nonahydrate 0.52 g were placed in a beaker and dissolved in 100 ml of ion-exchanged water. 26.31 g of sodium hydroxide was dissolved in 200 ml of ion-exchanged water, and the above-mentioned metal salt solution was added dropwise while stirring the aqueous solution maintained at 60 ° C. to obtain a precipitate. The precipitate was washed with about 3 liters of ion-exchanged water and dried overnight in a dryer at 60 ° C. 4. this dried precipitate
00 g was precisely weighed, and 3 ml of ion-exchanged water in which 0.060 g of potassium carbonate was dissolved was added and kneaded to form a slurry. The charged atomic ratio of the catalyst was 1: 0.33: 0.33: 0.017: 0.026 for iron: copper: zinc: chromium: potassium. The slurry was dried in a dryer at 60 ° C. for 2 hours. Thereafter, the mixture was transferred to a crucible and baked at 400 ° C. for 3 hours. The obtained powder was molded and sized to 16/32 mesh. 2.5 g of the sized product was precisely weighed and filled in a reduction tube, and subjected to a hydrogen reduction treatment at 300 ° C. and a hydrogen flow rate of 150 ml / min under normal pressure for 1 hour. After the hydrogen reduction treatment, when the catalyst layer was cooled, the reduction tube was sealed and left overnight. When the catalyst was recovered from the reduction tube, 1.0 g was precisely weighed and charged into the reaction tube after the heat generation and weight increase had almost disappeared. Performed for 30 minutes. After the pre-reaction reduction treatment, when the catalyst layer was cooled, the raw material gas was switched to CO ₂ / H ₂ = 1/3 mole composition and the pressure was increased. When the inside of the system became 70 kg / cm ² , the raw material gas flow rate was 90 ml / min. And the temperature was raised. After the temperature rise is completed, continue the catalytic activity test,
Initial reaction (30 minutes after heating at 300 ° C.), 20 hours later, 20 minutes
After 0 hour, the respective reaction products were analyzed online by gas chromatography. Table 1 shows the results.

Example 2 6.04 g of copper nitrate trihydrate, 7.44 of zinc nitrate hexahydrate
g, iron nitrate nonahydrate 30.30 g in a beaker 10
It was dissolved in 0 ml of ion-exchanged water. Ion exchange water 200
26.00 g of sodium hydroxide was dissolved in ml, and the above-mentioned metal salt solution was added dropwise while well stirring the aqueous solution kept at 60 ° C. to obtain a precipitate. The precipitate was washed with about 3 liters of ion-exchanged water and dried overnight in a dryer at 60 ° C.
5.00 g of the dried precipitate was precisely weighed, and 0.31 g of 20 wt% silica sol and 3 ml of ion-exchanged water in which 0.060 g of potassium carbonate were dissolved were added and kneaded to form a slurry.
The charged atomic ratio of the catalyst was iron: copper: zinc: silicon: potassium of 1: 0.33: 0.33: 0.030: 0.026.
Met. Thereafter, a catalyst was prepared in the same manner as in Example 1, and after a reduction treatment, a catalyst activity test was performed. Table 1 shows the test results.

Example 3 5.00 g of the precipitate obtained in Example 1 after drying at 60 ° C. was precisely weighed,
0.10 g of palladium acetate and 0.060 of potassium carbonate
3 g of ion-exchanged water in which g was dissolved was added and kneaded to form a slurry. The charged atomic ratio of the catalyst is iron: copper: zinc:
1: 0.33: 0.3 palladium: chromium: potassium
3: 0.013: 0.017: 0.026. Thereafter, a catalyst was prepared in the same manner as in Example 1, and after a reduction treatment, a catalyst activity test was performed. Table 1 shows the test results.

Comparative Example 1 6.04 g of copper nitrate trihydrate, 7.44 of zinc nitrate hexahydrate
g, iron nitrate nonahydrate 30.30 g in a beaker 10
It was dissolved in 0 ml of ion-exchanged water. Ion exchange water 200
26.00 g of sodium hydroxide was dissolved in ml, and the above-mentioned metal salt solution was added dropwise while well stirring the aqueous solution kept at 60 ° C. to obtain a precipitate. The precipitate was washed with about 3 liters of ion-exchanged water and dried overnight in a dryer at 60 ° C.
5.00 g of the dried precipitate was precisely weighed, and potassium carbonate 0.0
3 ml of ion-exchanged water in which 60 g is dissolved is added and kneaded.
A slurry was formed. The charged atomic ratio of the catalyst was 1: 0.33: 0.33: 0.026 for iron: copper: zinc: potassium. Thereafter, a catalyst was prepared in the same manner as in Example 1,
After the reduction treatment, a catalyst activity test was performed. Table 2 shows test results
Shown in

[0019]

[Table 1]

[0020]

[Table 2]

[0021]

As is clear from the above examples, by performing the catalytic hydrogenation reaction of carbon dioxide by the method of the present invention, a high CO ₂ conversion and ethanol selectivity can be obtained, and the catalyst activity decreases. It is small and can be used for a long time. Therefore, useful ethanol is industrially advantageously obtained from carbon dioxide by the method of the present invention, and the present invention has great industrial significance.

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁶ Identification symbol FI C07C 29/156 C07C 29/156 // C07B 61/00 300 C07B 61/00 300 (58) Field surveyed (Int.Cl. ⁶ , DB name) C07C 31/08 C07C 29/156

Claims (2)

(57) [Claims] An iron, copper, zinc, potassium and chromium and / or silicon containing copper / iron, zinc / iron, potassium /
The atomic ratio of iron, chromium or silicon / iron is each 0.
2-3.0, 0.2-3.0, 0.01-0.5, 0.
A method for producing ethanol, comprising catalytically hydrogenating carbon dioxide using a catalyst having a molecular weight of 001 to 0.2. 2. An alloy comprising: iron, copper, zinc, potassium, a group VIII element of the periodic table selected from cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium, and platinum; and chromium and / or silicon. The atomic ratio of copper / iron, zinc / iron, potassium / iron, group VIII element of the periodic table / iron, chromium or silicon / iron is 0.2 to 0.2, respectively.
3.0, 0.2-3.0, 0.01-0.5, 0.00
2. The method for producing ethanol according to claim 1, wherein carbon dioxide is catalytically hydrogenated using a catalyst having 001 to 2, and 0.001 to 0.2.