JP2011207843A - Method for producing alcohol having two or more carbon atoms - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a ≥2C alcohol in high safety, yield and selectivity, enabling industrial production of the alcohol by using carbon dioxide as a raw material without using petroleum-derived raw materials and biomass and solving problems of conventional technique.SOLUTION: There is provided the method for producing the ≥2C alcohol by reacting carbon dioxide with a reducing agent, wherein the method includes a step to reduce carbon dioxide by using a compound containing nitrogen and hydrogen as the reducing agent.

Description

The present invention relates to a method for producing an alcohol having 2 or more carbon atoms. More specifically, the present invention relates to a method for producing an alcohol having 2 or more carbon atoms that can be suitably used in a method for producing an industrially useful alcohol having 2 or more carbon atoms using carbon dioxide as a raw material.

Alcohols having 2 or more carbon atoms such as ethanol are widely used as raw materials and solvents for compound synthesis, but most are synthesized from petroleum-derived raw materials. In recent years, so-called bioalcohol fuels such as bioethanol have attracted attention as fuels for internal combustion engines such as automobiles as alternative fuels for fossil fuels such as petroleum. On the other hand, bioalcohol fuel has the problem that it must be made from raw materials such as trees and corn, which are feared to cause global desertification and food shortages in developing countries. Therefore, it is expected that such alcohol is industrially produced regardless of petroleum-derived raw materials and biomass.

As a conventional alcohol production method, various methods such as a synthesis method by hydrocarbon hydration reaction and a synthesis method by reduction of carbon dioxide have been developed. Of these, in the synthesis method by reduction of carbon dioxide, the reduction method by hydrogen is generally used, but hydrogen gas is a high-pressure, combustible gas, and it is necessary to fully consider legal restrictions for industrial use. There is. In other words, since the use of hydrogen gas is dangerous, it must be handled with great care, and equipment conforming to it must be used.

In addition, a method for producing ethanol in which carbon dioxide is catalytically hydrogenated using a catalyst containing iron, copper, zinc, and potassium in specific ratios (see, for example, Patent Document 1), and a rhodium-lithium catalyst supported on silica. Alternatively, it is disclosed that ethanol is produced by a catalytic hydrogenation reaction of carbon dioxide using a rhodium-iron catalyst supported on silica (for example, see Non-Patent Document 1). Further, if necessary, a first-stage reaction in which a compound containing carbon and hydrogen or carbon dioxide is supplied at the same time to contact the reduced metal catalyst at 400 to 700 ° C. and a reaction mixture of the first-stage reaction are optionally provided. By supplying water from the outside and reacting at a lower temperature, methane and carbon dioxide are supplied in a method for producing a lower alcohol comprising a second stage reaction in which a lower metal and a reduced metal catalyst are obtained. It is disclosed that lower alcohols containing methanol, ethanol, and propanol were obtained by contacting with a reduced iron oxide catalyst (see, for example, Patent Document 2). Moreover, the method of manufacturing ethanol by the hydration of ethylene using a phosphoric acid catalyst is disclosed (for example, refer nonpatent literature 2).

Japanese Patent No. 2685130 (page 1-2) JP 2004-143121 A (1-2, 9-10 pages)

Hitoshi Kusama, Hironori Arakawa “Journal of the Chemical Society of Japan”, 2001, Vol. 8, p. 483-485 15509 Chemical Products (Chemical Industry Daily) p.429-432

As described above, various methods have been studied as a method for producing an alcohol having 2 or more carbon atoms. However, as disclosed in Patent Document 1 and Non-Patent Document 1, by a catalytic hydrogenation reaction of carbon dioxide in the presence of a catalyst. In the production of alcohols having 2 or more carbon atoms, it is essential to use hydrogen under high pressure, and there are problems such as handling and problems in production facilities. Furthermore, the yield and selection of alcohols having 2 or more carbon atoms The rate was not sufficient. Further, even in the method of Patent Document 2, the yield and selectivity of alcohol having 2 or more carbon atoms are not sufficient. Thus, the conventionally known methods have problems in terms of ease of production, synthesis yield, and selectivity in producing alcohols having 2 or more carbon atoms. Furthermore, in recent years, bioethanol has attracted attention, but it has a problem that it must use biomass such as trees and plants as food.
By the way, if alcohol can be produced industrially using carbon dioxide as a raw material, it is expected to contribute to solving global environmental problems such as carbon dioxide emission regulations.
In order to synthesize alcohol having 2 or more carbon atoms using carbon dioxide as a raw material, it is necessary to go through a process of increasing the number of carbons (carbon increase reaction) and a reduction reaction, and this can be achieved efficiently and simply. One of the problems is that it can be done.

The present invention has been made in view of the above situation, and can industrially produce carbon dioxide as a raw material regardless of petroleum-derived raw materials and biomass, and solves the above-described problems in the prior art. It is an object of the present invention to provide a method capable of producing an alcohol having 2 or more carbon atoms that can be produced with high safety and that maintains high yield and selectivity.

As one of the methods for producing alcohols having 2 or more carbon atoms, the present inventor has focused on the synthesis of carbon dioxide by a carbon increase reaction and a reduction reaction, and has studied various synthesis methods. Conventionally, hydrogen has generally been used. Attention was paid to whether other compounds could be applied as the reducing agent. And it discovered that the compound containing nitrogen and hydrogen acts as a reducing agent, and when using this reducing agent and using carbon dioxide as a reaction raw material, under mild reaction conditions, an alcohol having 2 or more carbon atoms was obtained in a high yield. The present inventors have found that it is possible to manufacture with high selectivity and have conceived that the above-mentioned problems can be solved brilliantly, and have reached the present invention.
In the method for producing an alcohol having 2 or more carbon atoms according to the present invention, a compound containing nitrogen and hydrogen such as ammonia is used as a reducing agent in place of highly dangerous hydrogen as a reducing agent. Compared with the method for producing alcohols having 2 or more carbon atoms by the catalytic hydrogenation reaction, a safer compound is used as a reducing agent, so that the safety is high and it is excellent in that there are few restrictions on the apparatus for carrying out the reduction reaction and transportation. In addition to the conventional method, it is possible to selectively produce alcohol in a high yield and in comparison with the conventional method of producing an alcohol having 2 or more carbon atoms using carbon dioxide as a raw material. It can be said that this method is very useful industrially.

That is, the present invention is a method for producing an alcohol having 2 or more carbon atoms by reacting carbon dioxide with a reducing agent, and the production method reduces carbon dioxide using a compound containing nitrogen and hydrogen as a reducing agent. It is a manufacturing method of C2 or more alcohol including the process to do.
The present invention is described in detail below.

The method for producing an alcohol having 2 or more carbon atoms of the present invention may include other steps as long as it includes a step of reducing carbon dioxide using a compound containing nitrogen and hydrogen as a reducing agent.

In the method for producing an alcohol having 2 or more carbon atoms according to the present invention, carbon dioxide is used as a reaction raw material, but carbon dioxide is not only easily available but is recently discharged from factories and the like. Since carbon dioxide is regarded as a problem and reduction of emissions is required, if it can be converted into a useful compound, it is preferable from the viewpoint of dealing with environmental problems, especially worldwide. The present invention has extremely important technical significance for the problem of carbon dioxide emission control. The purity of carbon dioxide is not particularly limited.

The method for producing an alcohol having 2 or more carbon atoms of the present invention uses a compound containing nitrogen and hydrogen, which is safer than hydrogen that has been generally used as a reducing agent, as the reducing agent. Examples of the compound containing nitrogen and hydrogen used as ammonia, hydrazine, methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, propylamine, butylamine, methyl carbamate, ethyl carbamate, urea, formamide, N, N- Amines and amides such as dimethylformamide; one or two of carbamic acid, ammonium salts such as carbamic acid, ammonium carbamate, diammonium hydrogen carbonate, ammonium carbonate, ammonium hydrogen carbonate, ammonium oxalate Or more can be used. Among these, ammonia, hydrazine, urea, carbamic acid, ammonium carbamate, diammonium hydrogen carbonate, ammonium carbonate, ammonium hydrogen carbonate, and ammonium oxalate are preferable. More preferred are ammonia, urea, and ammonium carbamate, and particularly preferred is ammonia. The compound containing nitrogen and hydrogen generates hydrogen in the system by the selection of the catalyst described below, the hydrogen can also act as a reducing agent, carbon monoxide generated by reduction of carbon dioxide, Alkanes and the like can also contribute to the carbon increase reaction and the reduction reaction. In this case, the reaction may be one-stage or multistage.

In the reduction step, it is preferable to perform a reduction reaction using 0.001 to 1000 moles of a compound containing nitrogen and hydrogen as a reducing agent with respect to 1 mole of carbon dioxide. If there are less than 0.001 mol of nitrogen and hydrogen compounds as reducing agents with respect to 1 mol of carbon dioxide, the reduction reaction may not proceed sufficiently, and even if it exceeds 1000 mol, it is produced by the reduction reaction. The yield of the alcohol having 2 or more carbon atoms does not improve greatly, and is not preferable from the viewpoint of effective use of the reducing agent. More preferably, a compound containing nitrogen and hydrogen as a reducing agent is used at a ratio of 0.1 to 100 mol with respect to 1 mol of carbon dioxide, and more preferably nitrogen and hydrogen as a reducing agent are included. It is to use a compound in the ratio of 1-10 mol.
In the case of a gas phase reaction in which a compound containing carbon dioxide, nitrogen and hydrogen as a reducing agent is a gas, the reaction may be performed by circulating each compound at such a molar ratio. it can.

When the reaction in the reduction step is a gas phase reaction, the reaction may be performed by circulating an inert gas together with a compound containing carbon dioxide, nitrogen and hydrogen as a reducing agent. For example, when ammonia is used as a compound containing nitrogen and hydrogen as a reducing agent, ammonium carbamate, urea, or the like may be generated in the reaction system, and the reaction tube may be blocked. Thus, depending on the type of the compound containing nitrogen and hydrogen as the reducing agent, a solid product may be generated and the reaction tube may be blocked, but the compound containing nitrogen and hydrogen as the reducing agent At the same time, it is possible to prevent the reaction tube from being blocked by flowing an inert gas. The inert gas can be circulated by appropriately setting the circulation amount. As the inert gas, air, nitrogen, helium, argon, methane, water vapor and the like are preferable. Further, heating the reaction tube can decompose ammonium carbamate, urea, and the like, thereby preventing clogging.

The amount of water as a raw material is not particularly limited in the reduction step, but it is preferably a step of performing a reduction reaction under conditions of less than equimolar with respect to carbon dioxide. If a certain amount or more of water is present in the reduction reaction system, the catalyst may be largely deactivated. The amount of water present is more preferably 0.9 mol or less, and even more preferably 0.8 mol or less with respect to 1 mol of carbon dioxide.

The reduction step of the present invention is preferably performed at 20 to 1000 ° C. By carrying out at such a temperature, the yield of the alcohol having 2 or more carbon atoms can be increased. The reduction step is more preferably performed at 100 to 900 ° C, and further preferably performed at 200 to 800 ° C.
Moreover, the said reduction | restoration process is preferable from the point which raises the yield of C2 or more alcohol obtained by being performed under the pressure of 0.1-20 Mpa. More preferably, it is performed under a pressure of 0.1 to 15 MPa.
The time for the reduction step may be appropriately set depending on the amount of carbon dioxide to be used, but is preferably 10 minutes or longer. If it is shorter than 10 minutes, the reduction reaction does not proceed sufficiently, and the yield of the resulting alcohol having 2 or more carbon atoms may be lowered. The reduction step in the present invention is preferably performed using a catalyst as described below. However, in the case of performing a gas phase flow reaction, the reaction can be continuously performed until the catalyst deteriorates. It is also possible to carry out the reproduction.

The reduction step is preferably performed using a catalyst. By using a catalyst that exerts the action of promoting the reaction in the reduction step, the yield of the alcohol having 2 or more carbon atoms produced by the reduction reaction can be further increased, and a compound containing nitrogen and hydrogen as a reducing agent is used. In combination, the effects of the present invention can be made synergistically outstanding.
As a usage-amount of a catalyst, it is preferable that it is 99-0.00001 mol% with respect to 100 mol% of carbon dioxide. If the amount used is less than 0.00001 mol%, sufficient catalytic performance may not be exhibited. Even if the amount used exceeds 99 mol%, the yield of the alcohol having 2 or more carbon atoms obtained by the reduction reaction is further increased. The rate cannot be greatly improved, which is not preferable from the viewpoint of effective utilization of the catalyst. More preferably, it is 50-0.0001 mol% with respect to 100 mol% of carbon dioxide, More preferably, it is 20-0.0005 mol%.
When performing a gas phase reaction in a circulation system, the hourly space velocity (SV) is not particularly limited, but conditions of ¹ hr ⁻¹ or more are usually used. The hourly space velocity (SV) is a value defined by the volume of raw material passing through the reactor per hour (cm ³ / hr) / the volume of catalyst in the reaction vessel (cm ³ ), and is 1 hr ⁻¹ or more. In addition, the amount of the compound containing carbon dioxide, nitrogen and hydrogen, and the amount of the catalyst may be determined.

The catalyst may be used in a homogeneous system in which the catalyst is dissolved in the liquid phase, or a heterogeneous system in which the reaction is performed by suspending the catalyst in the liquid phase or using the catalyst as a solid phase. In addition, the heterogeneous form may be either a liquid phase reaction or a gas phase reaction. In the case of taking a homogeneous system, the group 3-12 element of the periodic table described later is composed of a catalyst containing at least one element and the group 1-2 and / or group 13-17 element of the periodic table. Oxides, nitrides, sulfides, fluorides, chlorides, bromides, nitrate compounds, sulfate compounds, acetate compounds, alkali metal salt compounds, alkalis that serve as promoters containing at least one element selected from the group Water or earth metal salt compound, ammonium salt compound, carbonyl compound, acetylacetonate compound, oxalic acid compound, phosphorus ligand-containing compound, nitrogen ligand-containing compound, carbene ligand-containing compound or the like as a reaction solvent What is necessary is just to melt | dissolve in an organic solvent or a water-containing organic solvent. In the case of a non-uniform form, not only is the catalyst recovered, regenerated, or reused, but particularly in the case of a gas phase reaction, the gas after the reaction can be easily recovered and reused. is there.

When using a catalyst in the method for producing an alcohol having 2 or more carbon atoms of the present invention, it is preferable to reduce and / or nitride the catalyst in advance before using it in the step of reducing carbon dioxide. By doing in this way, the catalytically active species suitable for the method for producing an alcohol having 2 or more carbon atoms of the present invention can be constructed.
The method for reducing and / or nitriding the catalyst is not particularly limited, but it is preferable to reduce and / or nitride using a gas containing at least one of alkane, hydrogen and ammonia. As the gas containing at least one of alkane, hydrogen and ammonia, a mixed gas with nitrogen, helium, argon, methane, water vapor or the like can be used, and the gas / inert containing at least one of alkane, hydrogen and ammonia It is preferable to use a gas containing gas at a ratio of 100/1 to 0.01 / 100. More preferably, the gas contains at least one of hydrogen and ammonia / inert gas at a ratio of 50/1 to 0.1 / 100.
The amount of the gas containing at least one of alkane, hydrogen and ammonia used for reduction and / or nitridation is such that hydrogen and / or ammonia is 0.1 to 100000 mol% with respect to 100 mol% of the catalyst. Is preferred. More preferably, the amount of hydrogen and / or ammonia is 0.5 mol% to 10000 mol% with respect to 100 mol% of the catalyst. Unreacted alkane and / or hydrogen and / or ammonia can be recovered and reused.
Moreover, it is preferable to perform reduction | restoration and / or nitridation of a catalyst at 20-1000 degreeC. More preferably, it is 100-700 degreeC, Most preferably, it is 100-600 degreeC.
The time for reducing and / or nitriding the catalyst is preferably 10 to 1440 minutes. More preferably, it is 30 to 720 minutes, and particularly preferably 60 to 300 minutes.
When performing a gas phase reaction in a flow system, the hourly space velocity (SV) for reduction and / or nitridation is not particularly limited, but a condition of ¹ hr ⁻¹ or more is usually used, and the SV value is used for the reduction reaction of the present invention. The catalyst may be reduced and / or nitrided until a suitable catalytically active species can be constructed.

The method for producing an alcohol having 2 or more carbon atoms of the present invention is preferably carried out using as a catalyst a compound having at least one element selected from the group consisting of elements of Group 3-12 of the periodic table. By performing the reaction in the presence of such a catalyst, the yield of the alcohol having 2 or more carbon atoms obtained by the reduction reaction can be sufficiently increased. Among these, as the catalyst, a compound having at least one element selected from the group consisting of elements of groups 4 to 12 of the periodic table is more preferable. More preferably, it is a compound having at least one element selected from the group consisting of Group 5-12 elements of the Periodic Table. One type or two or more types of catalysts can be used.
The “family” here means a group in the 18-group long periodic table.

As an element that the catalyst in the present invention has, among the elements of Group 3-12 of the periodic table, lanthanoid, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, rhenium, iron, At least one element selected from the group consisting of ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium, platinum, copper, silver, gold, zinc, and cadmium is preferred. More preferably, it is selected from the group consisting of lanthanides, tantalum, chromium, molybdenum, tungsten, manganese, rhenium, iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium, platinum, copper, silver, gold and zinc. At least one element, most preferably from lanthanides, tantalum, chromium, molybdenum, tungsten, manganese, rhenium, iron, ruthenium, cobalt, rhodium, iridium, nickel, palladium, platinum, copper, silver, gold and zinc At least one element selected from the group consisting of: Catalyzing a compound having at least one element selected from the group consisting of tantalum, chromium, molybdenum, tungsten, manganese, rhenium, iron, ruthenium, cobalt, rhodium, iridium, nickel, palladium, platinum, copper, silver and gold When used as, an alcohol having 2 or more carbon atoms can be obtained with a particularly high yield.
In particular, when nickel is used, it is more preferable that another element different from that coexists.

Moreover, in the method for producing an alcohol having 2 or more carbon atoms of the present invention, at least one element selected from the group consisting of elements of groups 1-2 and / or 13-17 of the periodic table is used as a promoter. It can also be used to further increase the catalytic activity. The co-catalyst refers to an auxiliary component that has an action of enhancing the catalytic action of the group 3-12 element of the periodic table as the main component. As at least one element selected from the group consisting of Group 1-2 and / or Group 13-17 of the Periodic Table, lithium, sodium, potassium, rubidium, cesium, beryllium, magnesium, calcium, strontium, At least one element selected from the group consisting of barium, boron, aluminum, gallium, indium, thallium, germanium, tin, lead, phosphorus, arsenic, antimony, bismuth, sulfur, selenium, tellurium, fluorine, chlorine and bromine preferable. More preferably, lithium, sodium, potassium, rubidium, cesium, beryllium, magnesium, calcium, strontium, barium, boron, aluminum, gallium, indium, thallium, germanium, tin, lead, phosphorus, antimony, bismuth, sulfur, selenium, At least one element selected from the group consisting of tellurium, fluorine and chlorine, most preferably lithium, sodium, potassium, rubidium, cesium, beryllium, magnesium, calcium, strontium, barium, boron, aluminum, gallium, It is at least one element selected from the group consisting of indium, germanium, tin, lead, antimony, bismuth, sulfur, selenium, tellurium and fluorine.
In the present invention, since the yield and selectivity of the alcohol having 2 or more carbon atoms to be obtained vary depending on the catalyst or promoter to be used, the catalyst or assistant to be used is selected according to the type of alcohol having 2 or more carbon atoms required. A catalyst can be selected. When the catalyst performance deteriorates, it can be regenerated by operations such as calcination, reduction and / or nitriding. In the case of a gas phase flow reaction, the outlet gas can be recovered and the reaction can be carried out using it as a raw material.

In the catalyst, the content of at least one element selected from the group consisting of Group 3 to 12 elements of the periodic table in the catalyst is 99 to 0.001% by mass with respect to 100% by mass of the entire catalyst. It is preferable. If the content of at least one element selected from the group consisting of Group 3 to 12 elements in the periodic table is less than 0.001% by mass, sufficient catalytic performance may not be exhibited, and Even if it exceeds 99% by mass, the yield of the alcohol having 2 or more carbon atoms obtained by the reduction reaction cannot be greatly improved, and it is economically disadvantageous. More preferably, the content of at least one element selected from the group consisting of Group 3 to 12 elements in the periodic table is 50 to 0.01% by mass with respect to 100% by mass of the entire catalyst, and more preferably. Is 20-0.05 mass%.
In addition, the whole catalyst here means the whole also including a support | carrier, when a catalytically active seed | species is carry | supported by the support | carrier (especially porous support | carrier) as follows.

The catalyst may be one in which a catalytically active species is supported on a carrier, particularly a porous carrier.
Among the catalysts used in the reaction mode of the present invention, there are those that exhibit the effects of the present invention or show outstandingly by being in a form supported on a carrier, so the catalyst is supported on a carrier. Forming can be said to be one of the preferred embodiments of the present invention. In particular, it is preferable to select the form supported on the carrier depending on the type of catalyst. For example, lanthanoids, tantalum, chromium, molybdenum, tungsten, manganese, rhenium, iron, ruthenium, cobalt, rhodium, iridium, nickel, palladium, platinum, copper, silver, gold, zinc, and the like are supported on a carrier. Thus, the catalytic action is sufficiently exhibited in the present invention.

In the case of being supported on the porous carrier, the porous carrier is not particularly limited, such as oxide, nitride, sulfide, etc., but silica, alumina, silica-alumina, zeolite, mesoporous material, lithium oxide , Sodium oxide, potassium oxide, cesium oxide, magnesium oxide, calcium oxide, barium oxide, lanthanoid oxide, titanium oxide, zirconium oxide, vanadium oxide, niobium oxide, tantalum oxide, zinc oxide, tin oxide, polyoxometalate, phosphoric acid Oxides and composite oxides such as zinc, aluminum phosphate, vanadium phosphate, lanthanoid phosphate, hydrotalcite, apatite, sepiolite, montmorillonite, diatomaceous earth, clay compounds, etc. and / or their nitrides and sulfides, activated carbon , Ion exchange resins, organic-inorganic composite compounds, etc. , And the can be used alone or in combination of two or more thereof. The elements constituting the carrier may be the same as or different from the catalyst and the promoter component, but are more preferably different elements. The form of the carrier may be any form such as fine powder, powder, granule, granule, pellet, extruded shape, ring shape, honeycomb, etc., and the support form may be uniform support, outer layer support, inner layer support, center support, etc. It may be a form.

The methods supported on the carrier include precipitation method, coprecipitation method, kneading method, gelation method, deposition method, impregnation method (equilibrium adsorption method / evaporation-drying method), ion exchange method, melting method, development method, water Examples thereof include a thermal synthesis method, an alloying method, a nanoparticle formation method, and a vapor deposition method. For example, when a solvent is used for loading in the impregnation method or the like, it can be prepared by mixing a catalyst precursor containing an element that becomes a catalytically active species and a carrier in a solvent and firing. The solvent may be water, an organic solvent or a water-containing organic solvent as long as it can dissolve the catalyst precursor. The catalyst preparation solvent, pH, preparation pressure, and preparation temperature may be appropriately set depending on the kind of the porous carrier and catalyst precursor, but when using an aqueous solution, the pH is preferably 0.5 to 14. The preparation is performed at 10 to 100 ° C. at 0.5 to 0.0001 MPa using a water solvent or a water-containing organic solvent set in between.
The firing temperature is preferably 100 to 1000 ° C. More preferably, it is 200-900 degreeC. The firing time is preferably 10 to 2880 minutes. More preferably, it is 30 to 1440 minutes.
In addition, the gas phase atmosphere during firing is not particularly limited, such as air, nitrogen, argon, oxygen, etc., and may be performed in air, with hydrogen / nitrogen at a ratio of 100/1 to 0.1 / 100. You may carry out in the gas atmosphere containing.

Examples of the catalyst precursor include oxides, nitrides, sulfides of elements that exhibit catalytic activity, such as at least one element selected from the group consisting of Group 3-12 elements of the Periodic Table. Fluoride, chloride, bromide, nitrate compound, sulfate compound, acetate compound, alkali metal salt compound, alkaline earth metal salt compound, ammonium salt compound, carbonyl compound, acetylacetonate compound, oxalate compound, phosphorus coordination It is preferable to use a child-containing compound, a nitrogen ligand-containing compound, a carbene ligand-containing compound, or the like. Among these, oxides, nitrides, fluorides, nitrate compounds, sulfate compounds, acetate compounds, alkali metal salt compounds, alkaline earth metal salt compounds, ammonium salt compounds, carbonyl compounds, acetylacetonate compounds, oxalic acid More preferred are compounds.

In the method for producing an alcohol having 2 or more carbon atoms of the present invention, the alcohol having 2 or more carbon atoms produced by reduction of carbon dioxide is a compound containing nitrogen and hydrogen used as a reducing agent, the type of catalyst, reaction conditions, etc. Of these, alcohols having 2 to 12 carbon atoms are preferable, and alcohols having 1 to 6 carbon atoms are more preferable. Specifically, methanol, ethanol, propanol, isopropanol, butanol, isobutanol, pentanol, hexanol, ethylene glycol, propanediol, butanediol, pentanediol, and hexanediol.

The method for producing an alcohol having 2 or more carbon atoms of the present invention has the above-described configuration, and uses carbon dioxide, which is required to reduce the emission amount, as a raw material, and further, as a reducing agent, compared to hydrogen that has been generally used so far. Since it is a method that can produce an alcohol having 2 or more carbon atoms in a high yield using a compound containing nitrogen and hydrogen that is highly safe and easy to handle, it is suitable as a method for producing an alcohol having 2 or more carbon atoms. This is a method that can be used.

The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to these examples. Note that “%” means “mass%” unless otherwise specified.

Catalyst Preparation Example 1 (10% Ru-13% Cs / Al ₂ O ₃ )
A powder (9 g) of γ-alumina (BET specific surface area 103 m ² / g) was added to 22 g of a ruthenium nitrate aqueous solution having a ruthenium content of 4.6%, and water was evaporated to dryness using a rotary evaporator. Drying was performed at ˜120 ° C. Thereafter, hydrogen reduction was performed at 300 ° C. for 1 hour using 5 vol% hydrogen / nitrogen gas to obtain 10% Ru / Al ₂ O ₃ (catalyst A). Next, using cesium nitrate, an aqueous solution was prepared so that Cs / Ru = 1 (molar ratio), catalyst A was added thereto, and water was evaporated to dryness using a rotary evaporator. Hydrogen reduction was carried out at 400 ° C. for 4 hours using 5 vol% hydrogen / nitrogen gas. The obtained powder was compressed by a press and then crushed and sieved to a particle size of 0.7 to 1.0 mm to obtain 10% Ru-13% Cs / Al ₂ O ₃ .

Catalyst Preparation Example 2 (10% Ir / Al ₂ O ₃ )
To a tetrahydrofuran solution in which iridium acetylacetonate (2.5 g) was dissolved, Al ₂ O ₃ having a particle size of 0.7 to 1.0 mm (9 g: calcined at 950 ° C. for 10 hours in an air atmosphere) was added. The water was evaporated to dryness. The obtained solid was calcined at 400 ° C. for 3 hours in an air atmosphere to obtain 10% Ir / Al ₂ O ₃ .

Catalyst Preparation Example 3 (10% Pd / Al ₂ O ₃ )
Al ₂ O ₃ (9 g: calcined at 950 ° C. for 10 hours in an air atmosphere) having a particle size of 0.7 to 1.0 mm was added to pure water in which palladium nitrate (2.2 g) was dissolved, and a rotary evaporator was used. Water was evaporated to dryness. The obtained solid was fired at 400 ° C. for 3 hours in an air atmosphere to obtain 10% Pd / Al ₂ O ₃ .

Catalyst Preparation Example 4 (10% Rh / SiO ₂ —Al ₂ O ₃ )
SiO ₂ —Al ₂ O ₃ (9 g) having a particle size of 0.7 to 1.0 mm is added to a tetrahydrofuran solution in which dodecacarbonyltetrarhodium (1.8 g) is dissolved, and water is evaporated to dryness using a rotary evaporator. Solidified. The obtained solid was fired at 400 ° C. for 3 hours in an air atmosphere to obtain 10% Rh / SiO ₂ —Al ₂ O ₃ .

Catalyst Preparation Example 5 (5% Rh / MgO)
Basic magnesium carbonate powder (20 g) was added to a tetrahydrofuran solution in which dodecacarbonyltetrarhodium (0.9 g) was dissolved, and water was evaporated to dryness using a rotary evaporator. The obtained solid was calcined at 400 ° C. for 3 hours in an air atmosphere. This was compressed by a press and then crushed and sieved to a particle size of 0.7 to 1.0 mm to obtain 5% Rh / MgO.

Catalyst Preparation Example 6 (CuO / ZnO / Al ₂ O ₃ )
It was prepared according to the following known literature.
M. Saito, T. Fujitani, M. Takeuchi, T. Watanabe, "Journal of Molecular Catalysis A: Chemical", (Rankoku), 1996, Vol. 311-318
As shown in Table 1, these catalysts and CuO / ZnO / Al ₂ O ₃ are referred to as catalysts (1) to (6), respectively.

Example 1
The bottom of a 5/8 inch reaction tube (length 41 cm) was filled with demister and glass wool, quartz sand was added to a height of 20.5 cm, and glass wool was filled. Subsequently, 10% Ru-13% Cs / Al ₂ O ₃ catalyst was added to a height of 4.8 cm and filled with glass wool, and quartz sand was further added to a height of 11 cm and filled with glass wool. A thermocouple in a 1/16 inch tube was inserted into the catalyst layer so that the internal temperature could be measured. The above reaction tube is put into an electric furnace, heated to 400 ° C. over 1 hour while circulating 100 mL / min of nitrogen and 10 mL / min of hydrogen at normal pressure (1 atm, 0.1 MPa), and further maintained at the same temperature for 2 hours. Then, the catalyst was reduced. After the reduction, the nitrogen and hydrogen flow was stopped, and the reaction was carried out by flowing 200 mL / min of ammonia and 100 mL / min of carbon dioxide at 400 ° C. for 1 hour at normal pressure (SV = 1000 h ⁻¹ ). The gas that emerged from the outlet of the reaction tube was passed through pure water (150 mL) in an Ichinose-type washing bottle and further passed through a 30% aqueous sulfuric acid solution (150 mL), and the gas obtained was collected by a 100 mL collection bottle. When pure water in the Ichinose-type washing bottle was analyzed by an FID type gas chromatograph, 19 μmol of methanol, 119 μmol of ethanol, and 36 μmol of acetonitrile were detected. Further, when the collected gas was analyzed by a TCD gas chromatograph, 55 mmol of hydrogen, 29 mmol of methane, and 0.36 mmol of carbon monoxide were detected.

Example 2
The reaction was carried out according to Example 1 except that the catalyst was 10% Ir / Al ₂ O ₃ and 200 mL / min of ammonia, 100 mL / min of carbon dioxide and 100 mL / min of nitrogen were passed at 400 ° C. for 1 hour at normal pressure. When pure water in the Ichinose-type washing bottle was analyzed by an FID type gas chromatograph, 110 μmol of ethanol was detected. Further, when the collected gas was analyzed by a TCD gas chromatograph, 6.1 mmol of hydrogen and 5.3 mmol of methane were detected.

Example 3
The reaction was carried out according to Example 1, except that the catalyst was 10% Pd / Al ₂ O ₃ and 200 mL / min of ammonia, 100 mL / min of carbon dioxide, and 100 mL / min of nitrogen were passed at 400 ° C. for 1 hour at normal pressure. When pure water in the Ichinose-type washing bottle was analyzed by an FID type gas chromatograph, 11 μmol of methanol and 44 μmol of ethanol were detected. Further, when the collected gas was analyzed by a TCD gas chromatograph, 0.3 mmol of hydrogen and 1.6 mmol of methane were detected.

Example 4
The reaction was carried out in accordance with Example 1 except that the catalyst was 10% Rh / SiO ₂ -Al ₂ O ₃ and 200 mL / min of ammonia, 100 mL / min of carbon dioxide and 100 mL / min of nitrogen were passed at 400 ° C. for 1 hour at normal pressure. Carried out. When pure water in the Ichinose-type washing bottle was analyzed by an FID type gas chromatograph, 14 μmol of ethanol was detected. Further, when the collected gas was analyzed by a TCD gas chromatograph, 8.5 mmol of hydrogen, 0.64 mmol of methane, and 5.9 μmol of carbon monoxide were detected.

Example 5
The reaction was carried out according to Example 1 except that the catalyst was 5% Rh / MgO, and 200 mL / min of ammonia, 100 mL / min of carbon dioxide, and 100 mL / min of nitrogen were passed at 400 ° C. for 1 hour at normal pressure. When pure water in the Ichinose-type washing bottle was analyzed by an FID type gas chromatograph, 150 μmol of ethanol was detected. Further, when the collected gas was analyzed by a TCD gas chromatograph, 4.7 mmol of hydrogen and 4.1 μmol of carbon monoxide were detected.

Comparative Example 1
The reaction was carried out according to Example 1 except that the reduction temperature was 250 ° C., the catalyst was CuO / ZnO / Al ₂ O ₃ , and 90 mL / min of carbon dioxide at normal pressure and 30 mL / min of hydrogen were passed at 250 ° C. for 1 hour. did. When pure water in the Ichinose-type washing bottle was analyzed by an FID type gas chromatograph, methanol, ethanol and acetonitrile were not detected. Further, when the collected gas was analyzed by a TCD gas chromatograph, methane and carbon monoxide were not detected.
The results of Examples 1 to 5 and Comparative Example 1 are shown in Table 2. In Table 2, ND represents that it was not detected.

From the results in Table 2, it was confirmed that it was possible to obtain alcohol having 2 or more carbon atoms by reducing carbon dioxide at normal pressure using ammonia as a reducing agent. On the other hand, when hydrogen was used as the reducing agent, carbon dioxide could not be reduced at normal pressure.

Claims (2)

A method for producing an alcohol having 2 or more carbon atoms by reacting carbon dioxide with a reducing agent,
The method for producing an alcohol having 2 or more carbon atoms, comprising a step of reducing carbon dioxide using a compound containing nitrogen and hydrogen as a reducing agent. 2. The carbon number according to claim 1, wherein the reduction step is performed using as a catalyst a compound having at least one element selected from the group consisting of elements of Group 3 to 12 of the periodic table. A method for producing two or more alcohols.