JP2012211100A - Method and catalyst for producing methanol - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing methanol, which causes a low degree of a decrease in activity even if a small amount of water, carbon dioxide and the like exists in a raw material, thereby obtaining the methanol stably at low temperature and low pressure and upon continuous reaction.SOLUTION: In the method for producing the methanol, the reaction of a raw material gas that contains carbon monoxide and hydrogen is conducted in the presence of an alcohol as a solvent by using a catalyst. An alkali metal formate, or the homogeneous catalyst, and a solid catalyst that contains copper, aluminum and alkali metal are used as the catalyst.

Description

  The present invention relates to a method for producing methanol and a catalyst for producing methanol. More specifically, the present invention relates to a methanol production method for obtaining a product with high efficiency when producing methanol from carbon monoxide and hydrogen, and a highly active catalyst for methanol production.

  Generally, when industrially synthesizing methanol, carbon monoxide and hydrogen (synthetic gas) obtained by steam reforming natural gas mainly composed of methane are used as raw materials, and copper, zinc-based, etc. The catalyst is synthesized in a fixed bed gas phase method under severe conditions of 200 to 300 ° C. and 5 to 25 MPa (see, for example, Non-Patent Document 1). As shown below, the reaction mechanism is a sequential reaction in which methanol and water are produced by hydrogenation of carbon dioxide, and then the produced water reacts with carbon monoxide to produce carbon dioxide and hydrogen (water gas shift reaction). The theory is generally accepted.

CO ₂ + 3H ₂ → CH ₃ OH + H ₂ O (1)
H ₂ O + CO → CO ₂ + H ₂ (2)
CO + 2H ₂ → CH ₃ OH (3)
Although this reaction is an exothermic reaction, it is difficult to remove heat efficiently due to poor heat conduction in the gas phase method, so the conversion rate when passing through the reactor is kept low, and unreacted high-pressure raw material gas Recycling is a difficult process in terms of efficiency. However, taking advantage of the fact that reaction inhibition by water and carbon dioxide contained in synthesis gas is difficult, various plants are in operation.

  On the other hand, various methods for improving the heat removal rate by synthesizing methanol in a liquid phase have been studied. Among them, a method using a catalyst having high activity at a low temperature (about 100 to 180 ° C.) is thermodynamically advantageous for the production system, and has attracted attention (for example, see Non-Patent Document 2, etc.). The catalyst used is an alkali metal alkoxide, but these methods have reported a decrease in activity due to water and carbon dioxide that are always contained in the synthesis gas, and none of them have been put into practical use (Non-patent Document 3). This is because a highly active alkali metal alkoxide is converted into a low activity and stable formate during the reaction. In order to prevent the decrease in activity, it is necessary to remove water and carbon dioxide in the raw material gas up to the ppb order. However, such pretreatment increases the cost and is not realistic.

  Therefore, a catalyst having a small decrease in activity due to water and carbon dioxide has been studied. For example, a system in which one or both of an alkali metal catalyst and an alkaline earth metal catalyst coexist with a hydrocracking catalyst has been found. (For example, see Patent Document 1). Patent Document 1 describes that Cu / Mn, Cu / Re, and the like are effective as a hydrocracking catalyst. Further, Cu / MgO has been found as a more highly active hydrocracking catalyst, and Cu / MgO supported on Cu / MgO as a co-catalyst such as Na carbonate and Na formate as a catalyst with little deterioration with time of activity. MgO-Na has been found (see, for example, Patent Document 2).

JP2001-862701 JP2007-216178

J. C. J. Bart et al., Catal. Today, 2, 1 (1987) Seiichi Oyama, PETROTECH, 18 (1), 27 (1995) S. Ohyama, Applied Catalysis A: General, 180, 217 (1999)

  The present invention aims to further reduce the deterioration of activity over time, and even if a small amount of carbon dioxide, water, etc. are mixed in the methanol synthesis raw material gas, the degree of catalyst activity decrease is low, and A catalyst capable of synthesizing formate and methanol at low temperature and low pressure and a method for synthesizing methanol in a liquid phase are provided.

  The features of the present invention are as described below.

  (1) A method for producing methanol via a formate by performing a reaction using a catalyst in the presence of a raw material gas containing carbon monoxide and hydrogen and an alcohol as a solvent, wherein the catalyst is homogeneous A method for producing methanol, comprising: a system catalyst and a solid catalyst, wherein the homogeneous catalyst contains an alkali metal formate, and the solid catalyst contains copper, alumina, and an alkali metal.

  (2) The method for producing methanol according to (1), wherein the alkali metal formate of the homogeneous catalyst is sodium formate or potassium formate.

  (3) The method for producing methanol according to (1) or (2), wherein the alkali metal contained in the solid catalyst is contained as sodium carbonate or sodium formate.

  (4) The solid catalyst comprises an alkali metal salt supported by an impregnation method on a solid comprising copper and alumina obtained by drying and calcining a precipitate containing copper and aluminum produced by a coprecipitation method. The method for producing methanol according to any one of (1) to (3), wherein the method is a solid catalyst.

  (5) The method for producing methanol according to (4), wherein the precipitate is produced by a coprecipitation method while keeping a hydrogen ion concentration constant in a range of pH = 8 to 11.

  (6) The method for producing methanol according to any one of (1) to (5), wherein a hydrocracking catalyst is allowed to coexist with the catalyst.

  (7) In the method for producing methanol according to any one of (1) to (6), after separating methanol from the unreacted formic acid ester and the generated methanol after producing methanol, the separated formic acid A method for producing methanol, comprising adding a hydrocracking catalyst to an ester and methanol to hydrogenate the formate ester to further produce methanol.

  (8) In the method for producing methanol according to any one of (1) to (6), after the methanol is formed, the formate is separated from the reaction system from a mixture of unreacted formate and generated methanol. Then, a hydrogenolysis catalyst is added to the formate ester after the separation, and the formate ester is hydrogenated to further produce methanol.

  (9) The method for producing methanol according to any one of (1) to (8), wherein the alcohol is a primary alcohol.

  (10) A catalyst for producing methanol used in the production of a formate ester and methanol in the presence of a raw material gas containing carbon monoxide and hydrogen and an alcohol as a solvent, comprising an alkali metal formate and a solid catalyst A catalyst for methanol production, wherein the solid catalyst comprises an alkali metal supported on a solid containing copper and alumina.

  (11) The catalyst for methanol production according to (10), wherein the alkali metal formate is sodium formate or potassium formate, and sodium carbonate or sodium formate is supported on the solid composed of copper and alumina. .

In the present invention, in a system in which an alkali metal formate of a homogeneous catalyst and a solid catalyst containing Cu, Al ₂ O ₃ , and an alkali metal coexist, a solvent from carbon monoxide and hydrogen, which is a synthetic raw material gas When methanol is produced in the presence of alcohol, methanol can be stably synthesized with high efficiency in a continuous reaction at low temperature and low pressure. Further, even if a small amount of water, carbon dioxide, or the like is mixed in the synthetic raw material gas, the degree of decrease in the activity of the catalyst is low, so that methanol can be produced at a low cost.

1 is a reactor for carrying out the low-temperature liquid phase methanol synthesis of the present invention. 2 is a change with time in CO conversion in the reaction described in Example 1. FIG. 2 is a change with time of the CO conversion rate in the reaction described in Example 2. FIG. 4 is a change with time of the CO conversion rate in the reaction described in Example 3. FIG. 4 is a change with time in CO conversion in the reaction described in Example 4. FIG. 4 is a change with time in CO conversion in the reaction described in Example 5. FIG. 6 is a change with time in CO conversion in the reaction described in Example 6. FIG. 4 is a change with time in CO conversion in the reaction described in Example 7. FIG. 4 is a change with time of CO conversion in the reaction described in Example 8. FIG. 2 is a change with time of CO conversion in the reaction described in Example 9. FIG. 3 is a change with time in CO conversion in the reaction described in Comparative Example 1. FIG. 3 is a change with time of the CO conversion rate in the reaction described in Comparative Example 2. FIG. 3 is a change with time in CO conversion in the reaction described in Comparative Example 3. FIG. 3 is a change with time in CO conversion in the reaction described in Comparative Example 4. FIG.

  Hereinafter, the present invention will be described in detail.

As a result of intensive studies, the inventors of the present invention added Cu and Al ₂ O ₃ in addition to the alkali metal formate of a homogeneous catalyst in a semi-batch continuous reaction in which a catalyst and a solvent are charged into a reactor and a raw material gas is supplied. And a catalyst containing an alkali metal, it has been found that it can be stably produced at a high yield in the production of methanol from at least one of carbon monoxide and carbon dioxide, and hydrogen and alcohols. It came to.

  The production method of formate ester and methanol in the present invention is presumed to be based on the following reaction formula (an example in which the alcohol is a chain or alicyclic hydrocarbon having a hydroxyl group attached thereto) ).

ROH + CO → HCOOR (4)
HCOOR + 2H ₂ → CH ₃ OH + ROH (5)
(Where R represents an alkyl group)
However, when water is present in the reaction system, it is considered that the reaction may proceed based on the following reaction formula, and it is estimated that formate or methanol is generated in parallel with the reaction formula.

CO + H ₂ O → CO ₂ + H ₂ (6)
CO ₂ + H ₂ + R-OH → HCOOR + H ₂ O (7)
HCOOR + 2H ₂ → CH ₃ OH + R-OH (8)
Therefore, the raw material for producing methanol is at least one of carbon monoxide and hydrogen, carbon dioxide and hydrogen, and alcohols can be recovered and reused. In the reaction represented by the formula (4), an alkali metal formate of a homogeneous catalyst or an alkali metal catalyst that can be converted into an alkali metal formate during the reaction exhibits a catalytic action, and the reaction represented by the formula (5) The hydrocracking catalyst is catalytic. According to the method of the present invention, even if a small amount of water and carbon dioxide are present in the raw material gas, the decrease in the activity of the catalyst is small.

For example, methanol can be continuously produced by a reaction process as shown in FIG. The semi-batch reactor 2 is charged with a solid catalyst containing Cu and Al ₂ O ₃ in addition to a homogeneous catalyst composed of alkali metal formate, together with solvent alcohol, and a synthesis gas mainly composed of carbon monoxide gas and hydrogen gas. Supply one. The product 3 at the outlet of the reactor (formate ester, methanol) and the unreacted gas mixture 3 is cooled by the cooler 4 and separated into the unreacted gas 5 and the liquid mixture 6 of formate ester and alcohol. The latter is separated into formate ester 8 and methanol 9 in distillation column 7 installed in the next stage. When the conversion rate is low, it is possible to supply the unreacted gas 5 to the semi-batch reactor 2 again, but when it is obtained in high yield, the unreacted gas is used as a heat source (fuel) for synthesis gas production. To do.

  Examples of the alkali metal formate of the homogeneous catalyst include potassium formate, sodium formate, cesium formate, and rubidium formate. In particular, it is preferable to use sodium formate or potassium formate because the catalytic activity is increased.

  Moreover, it may replace with an alkali metal formate and may use the alkali metal catalyst which can take the form of a formate during reaction, and the form at the time of reaction preparation is not specifically limited.

  Examples of such an alkali metal catalyst include potassium carbonate and potassium methoxide. When potassium carbonate is used, it is presumed that it has changed to potassium formate by the reaction shown below. When charged in other forms, it is presumed to change to a stable formate.

K ₂ CO ₃ + H ₂ O → 2KOH + CO ₂ (9)
KOH + CO → HCOOK (10)
Examples of the solid catalyst that coexists with the alkali metal formate or the alkali metal catalyst that can be changed to the alkali metal formate include Cu / Al ₂ O ₃ / alkali metal. The stability is improved by supporting the alkali metal component on Cu / Al ₂ O ₃ . The alkali metal is preferably Na. Chemical form of Na component is not limited, for example, HCOONa, Na ₂ carries a CO ₃ was _{Cu / Al 2 O 3 / HCOONa} , Cu / Al 2 O 3 / Na 2 CO 3 easy obtained good results. However, a part of the supported alkali metal component may be dissolved in the solvent alcohol, and the dissolved alkali metal component can be a homogeneous catalyst showing activity in the CO insertion reaction into the alcohol. In such a case, methanol can be produced without using a homogeneous catalyst composed of alkali metal formate.

The preparation of Cu / Al ₂ O ₃ may be performed by a usual method such as an impregnation method, a precipitation method, a sol-gel method, a coprecipitation method, an ion exchange method, a kneading method, and an evaporation to dryness method, and is not particularly limited. Although it is not, good results are easily obtained by the coprecipitation method.

In the catalyst preparation by the coprecipitation method, an aqueous solution in which a precursor of Cu and Al components is dissolved and an aqueous solution in which a precipitant is dissolved are prepared, and these are mixed to obtain a precipitate. The precursor of the Cu and Al components may be any precursor that dissolves in water. For example, copper nitrate trihydrate or aluminum nitrate nonahydrate can be used. In addition, the CO conversion rate varies greatly depending on the pH that is kept constant during preparation by the coprecipitation method. The pH for preparing Cu / Al ₂ O ₃ is preferably 8 to 11, more preferably 8 to 10, and further preferably 9 to 10. Na ₂ CO ₃ is preferred as the precipitant used. However, when the pH is set in a range exceeding 11, if Na ₂ CO ₃ is used as the precipitating agent, the amount used as the precipitating agent is remarkably increased, which is not economical. The chemical form of the obtained precipitate is presumed to be a hydroxide of Cu and Al components, and the obtained precipitate needs to be dried and fired. The drying may be performed under conditions that can remove moisture from the precipitate, and the conditions are not limited. For example, the drying can be performed at 120 ° C. for 10 hours. There are no particular limitations on the firing conditions, but for example, the firing can be carried out in air at 400 ° C. for 2 hours. By performing these drying and firing, it is presumed that the Al component takes the form of Al ₂ O ₃ having a large specific surface area, and the Cu component is highly dispersed. The Cu component is also considered to be in the form of an oxide after the firing step.

The method of supporting the Na component on Cu / Al ₂ O ₃ is not particularly limited, but good results are easily obtained by the impregnation method or the evaporation to dryness method. The amount of the Na component supported with respect to Cu / Al ₂ O ₃ is not less than the minimum amount that exhibits the effect, and is not particularly limited, but is preferably in the range of 0.1 to 60 mass%, more preferably 1 to 40 mass%. Yes, more preferably 3 to 30 mass%. Further, sodium formate, sodium carbonate and the like are preferable as the salt of the Na component to be supported. These Na components may be eluted depending on the reaction solvent, but some of them are present on the solid catalyst without being eluted, and it is presumed that they function as a promoter. On the other hand, Cu / Al ₂ O ₃ which does not carry Na salt has low activity, and degradation of activity over time is observed in continuous reaction. Therefore, the addition effect of the alkali metal is in activity improvement and activity reduction suppression. Although the expression mechanism of the activity lowering suppression effect by loading Na salt on Cu / Al ₂ O ₃ is unknown, the activity improving effect is estimated as follows.

Alkali metals such as Na and K supported on Cu / Al ₂ O ₃ are catalytic components that are active in the CO insertion reaction into alcohol (formula (4)) as homogeneous catalysts, and hydrogenolysis of formate esters. It is considered that the reaction proceeds efficiently because the active sites of these reactions are close to each other by the support on Cu / Al ₂ O ₃ which shows activity in the reaction (formula (5)). That is, an alkali metal such as Na on the solid catalyst becomes an active site to produce a formate ester by the above CO insertion reaction, and the formate ester is hydrocracked at an adjacent active site of Cu / Al ₂ O ₃ to produce methanol. Is estimated to be generated efficiently.

  Even when added in a chemical form other than alkali metal formate, it is assumed that alkali metal components such as Na and K take the chemical form showing activity in formula (4) in the reaction system, so that the same effect is exhibited. Is done. Therefore, in addition to Na, which has the greatest effect, the same effect can be obtained with alkali metals such as K, Cs, and Rb that exhibit chemically similar properties.

  The above-mentioned solid catalyst needs to be activated by reduction treatment before the reaction. For example, it is carried out by treating at 400 ° C. under a hydrogen flow. It is presumed that copper oxide is changed to metallic copper by the reduction treatment, and metallic copper contributes to the reaction as an active site of the hydrogenolysis reaction.

  The above-described solid catalyst containing Cu, Al, and alkali metal mainly exhibits a catalytic action in the hydrogenolysis of the produced formate ester, but also exhibits a catalytic action in a CO insertion reaction into a solvent alcohol. Therefore, it is possible to produce methanol using only a solid catalyst without using an alkali metal formate as a homogeneous catalyst. However, the reaction activity is remarkably low as compared with the case of using a homogeneous catalyst.

  The alcohol used in the reaction may be a chain or alicyclic hydrocarbon having a hydroxyl group, a phenol and a substituted product thereof, or a thiol and a substituted product thereof. These alcohols may be any of primary, secondary and tertiary, but primary alcohols are preferred from the viewpoint of reaction efficiency, etc., and lower alcohols such as methyl alcohol and ethyl alcohol are the most common. is there.

  The reaction can be carried out in either the liquid phase or the gas phase, but a system in which mild conditions can be selected can be employed. Specifically, a temperature of 70 to 250 ° C. and a pressure of 3 to 100 atm (3 to 100 × 1013.25 hPa) are suitable conditions, and more preferably a temperature of 120 to 200 ° C. and a pressure of 15 to 80 atm (15 to 80 × 1013.25 hPa), but not limited thereto. Alcohols only need to have such an amount that the reaction proceeds, but more than that can be used as a solvent. In the above reaction, in addition to alcohols, an organic solvent can be used as appropriate.

  The resulting formic acid ester can be purified by a conventional method such as distillation, but can also be directly used for the production of methanol from a mixture of formic acid ester and methanol. That is, methanol can be produced by hydrogenolysis of formate.

Hydrocracking catalysts are used for hydrocracking. For example, common hydrocracking catalysts such as Cu, Pt, Ni, Co, Ru, and Pd can be used, but only Cu / Al ₂ O ₃ based catalysts can be used. Can also be used. By making these general hydrocracking catalysts coexist in the reaction system for producing formate and methanol from the raw material gas and alcohol, it is possible to increase methanol selectivity and efficiently produce methanol. is there.

  In addition, when it is difficult to produce methanol in one step under the reaction conditions with high formate ester selectivity, the product obtained in the reaction is separated from the reaction system by distillation or the like, It is also possible to hydrogenate the formate ester in the presence of a hydrocracking catalyst and hydrogen to further obtain methanol. The methanol yield can also be improved by bringing the mixture of formate ester and methanol thus produced into contact with a hydrocracking catalyst and converting the formate ester in the mixture into methanol.

  This hydrocracking reaction may be carried out using the product obtained without carrying out the separation operation of the product containing formate ester and methanol as it is as the raw material, or the formate ester separated from the product containing formate ester and methanol. You may implement about the compound which has as a main component.

In the method using the catalyst of the present invention, methanol can be obtained even if only CO ₂ is used as the carbon source in the raw material gas, but the activity is remarkably lower than in the case of using only CO. Moreover, the lower the concentration of CO ₂ and H ₂ O contained in the source gas containing CO as a main component as a carbon source, the higher the yield of methanol can be obtained. The effect on CO conversion and methanol yield is small. However, if it is contained at a concentration higher than that, the CO conversion rate and the methanol yield decrease.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.

  The CO conversion rates described in the following examples and comparative examples were calculated by the following formula.

CO conversion rate (%) = [1− (number of moles of CO recovered after reaction) / (number of moles of supplied CO)] × 100
(Example 1)
Using an autoclave with an internal volume of 100 ml, add 27.8 ml of methanol as a solvent, and further add 10 mmol of homogeneous catalyst potassium formate: Furthermore, Cu (NO ₃ ) ₂ .3H ₂ O: 10.4 g , Al (NO ₃ ) ₃ · 9H ₂ O: 16.1 g as raw material, Na ₂ CO ₃ : 70.0 g as a precipitant, and a precipitate obtained by coprecipitation while maintaining pH = 9.7, then dried and calcined Cu / Al ₂ O ₃ was prepared by treatment, and Cu / Al ₂ O ₃ (the weight of the catalyst after reduction) was impregnated with HCOONa so as to be 9.0 mass%. 3 g of Al ₂ O ₃ / HCOONa is added after hydrogen reduction treatment, then synthesis gas (CO 30.0 vol%, H ₂ 60.0 vol%, Ar balance) is supplied at 60 ml / min, and the condition is 160 ° C-4.2 MPa A continuous reaction was carried out.

The gas composition and reaction products at the autoclave outlet were analyzed by gas chromatography. Fig. 2 shows the time course of CO conversion. Compared to the case of using Cu / MgO _X / HCOONa (X is a chemically acceptable value) shown in Comparative Example 1 described later, the CO conversion rate is stable, and the catalyst amount / feed gas supply amount is Even under these relatively small conditions, a stable CO conversion of over 40% was obtained. The ratio of methanol / formic acid ester in the product was 89% / 11%.
(Example 2)
The reaction was carried out by the method described in Example 1 except that the pH at which Cu / Al ₂ O ₃ was prepared by coprecipitation was set to 8.5. Fig. 3 shows the change over time in the CO conversion rate. The CO conversion rate was a little less than 40%, which was lower than that of Example 1, but a stable result was obtained in the same manner. The ratio of methanol / formic acid ester in the product was 90% / 10%.
(Example 3)
The reaction was carried out by the method described in Example 1 except that the pH at which Cu / Al ₂ O ₃ was prepared by coprecipitation was set to 10.1. FIG. 4 shows the change over time in the CO conversion rate. The CO conversion rate was about 20%, which was lower than that of Examples 1 and 2, but similarly stable results were obtained. The ratio of methanol / formate ester in the product was 36% / 64%.
(Example 4)
Other than preparing Cu / Al ₂ O ₃ by evaporation to dryness using Al ₂ O ₃ (Catalyst Society Reference Catalyst: JRC-ALO-1) and Cu (NO ₃ ) ₂ · 3H ₂ O as a raw material, The reaction was carried out by the method described in Example 1. FIG. 5 shows the change over time in the CO conversion rate. The CO conversion rate was about 10%, which was significantly lower than that in Examples 1 and 2, but stable results were obtained. The ratio of methanol / formate ester in the product was 6% / 94%.
(Example 5)
Cu / Al ₂ O ₃ was prepared by precipitation method in which Cu (NO ₃ ) ₂ · 3H ₂ O was added dropwise to Al ₂ O ₃ (Catalyst Society reference catalyst: JRC-ALO-1) slurry while maintaining pH = 9.7. Otherwise, the reaction was carried out by the method described in Example 1. The time course of CO conversion is shown in FIG. The CO conversion was about 20%, which was lower than that of Examples 1, 2, and 4. However, stable results were obtained in the same manner. The ratio of methanol / formate ester in the product was 72% / 28%.
(Example 6)
The reaction was carried out by the method described in Example 1 except that the amount of synthesis gas (CO 30.0 vol%, H ₂ 60.0 vol%, Ar balance) was 30 ml / min. FIG. 7 shows the change over time in the CO conversion rate. Compared with Example 1, the CO conversion increased and was about 70%.
(Example 7)
Instead of the _{Cu / Al 2 O 3 / HCOONa} , Cu / Al 2 O 3 solid catalyst prepared by impregnation of Na ₂ CO ₃ so that 9.0Mass% relative Cu / Al ₂ O ₃ / Na _The reaction was carried out by the method described in Example 1 except that ₂ CO ₃ was used. FIG. 8 shows the change over time in the CO conversion rate. Compared to the case of supporting HCOONa, the CO conversion was slightly lower, but stable results were obtained.
(Example 8)
The reaction was carried out by the method described in Example 1 except that 10 mmol of sodium formate was added instead of 10 mmol of potassium formate. FIG. 9 shows the change over time in the CO conversion rate. Compared to the case of using potassium formate, the CO conversion was slightly lower, but stable results were obtained.
(Example 9)
Syngas addition to using _{(CO 30.0vol%, H 2 60.0vol} %, CO2 1.0vol%, Ar balance) as starting material The reaction was performed by the method described in Example 1. FIG. 10 shows the change over time in the CO conversion rate. Although the CO conversion rate was reduced to about half, stable results were obtained.
(Comparative Example 1)
The reaction was carried out by the method described in Example 1 except that Cu / MgO _X / HCOONa (X is a chemically acceptable value) was used instead of Cu / Al ₂ O ₃ / HCOONa. FIG. 11 shows the change over time in the CO conversion rate. Compared to Cu / Al ₂ O ₃ / HCOONa described in Example 1, the change with time in CO conversion decreased from slightly over 40% to slightly under 40%, and became large. The ratio of methanol / formic acid ester in the product was 91% / 9%.
(Comparative Example 2)
The reaction was carried out by the method described in Example 1 except that Cu / CeO _X / HCOONa (X is a chemically acceptable value) was used instead of Cu / Al ₂ O ₃ / HCOONa. FIG. 12 shows the change over time in the CO conversion rate. Compared with Cu / Al ₂ O ₃ / HCOONa described in Example 1, the change with time was stable, but the CO conversion decreased to 20% or less. The ratio of methanol / formate ester in the product was 65% / 35%.
(Comparative Example 3)
The reaction was carried out by the method described in Example 1 except that Cu / ZrO ₂ / HCOONa was used instead of Cu / Al ₂ O ₃ / HCOONa. FIG. 13 shows the change over time in the CO conversion rate. Compared with Cu / Al ₂ O ₃ / HCOONa described in Example 1, the change with time was stable, but the CO conversion decreased to 20% or less. The ratio of methanol / formate ester in the product was 50% / 50%.
(Comparative Example 4)
The reaction was carried out by the method described in Example 1 except that Cu / Al ₂ O ₃ not impregnated with HCOONa was used instead of Cu / Al ₂ O ₃ / HCOONa. FIG. 14 shows the change over time in the CO conversion rate. Compared with Example 1, the activity was low, and the CO conversion rate decreased with time. The ratio of methanol / formate ester in the product was 32% / 68%.

From the above examples and comparative examples, Cu / Al ₂ O ₃ / HCOONa is more active than other Cu-based catalysts and has little deterioration over time (high stability), so use the catalyst. Thus, the catalyst cost can be reduced and methanol can be produced at low cost.

1 Syngas
2 Semi-batch reactor
3 Mixture of product and unreacted gas
4 Cooler
5 Unreacted gas
6 Liquid mixture of formate and methanol
7 Distillation tower
8 Formate
9 Methanol

Claims (11)

A method for producing methanol via a formate ester by performing a reaction using a catalyst in the presence of a raw material gas containing carbon monoxide and hydrogen and an alcohol as a solvent,
The catalyst comprises a homogeneous catalyst and a solid catalyst,
The homogeneous catalyst comprises an alkali metal formate;
The method for producing methanol, wherein the solid catalyst contains copper, alumina, and an alkali metal.   The method for producing methanol according to claim 1, wherein the alkali metal formate of the homogeneous catalyst is sodium formate or potassium formate.   The method for producing methanol according to claim 1 or 2, wherein the alkali metal contained in the solid catalyst is contained as sodium carbonate or sodium formate.   The solid catalyst is obtained by impregnating an alkali metal salt with a solid made of copper and alumina obtained by drying and firing a precipitate containing copper and aluminum produced by a coprecipitation method. The method for producing methanol according to any one of claims 1 to 3, wherein:   5. The method for producing methanol according to claim 4, wherein the precipitate is produced by a coprecipitation method while keeping a hydrogen ion concentration constant in a range of pH = 8 to 11. 5.   The method for producing methanol according to any one of claims 1 to 5, wherein a hydrocracking catalyst is allowed to coexist with the catalyst.   In the manufacturing method of methanol of any one of Claims 1-6, after producing | generating methanol, after separating unreacted formate ester and produced | generated methanol from the reaction system, the formate ester and methanol after the said separation | separation A method for producing methanol, comprising adding a hydrocracking catalyst to hydrogenating formate to further produce methanol.   In the manufacturing method of methanol of any one of Claims 1-6, after isolate | separating this formate ester from a reaction system from the mixture of the unreacted formate ester and the produced | generated methanol after producing | generating methanol, the said separation | separation The method for producing methanol according to any one of claims 1 to 6, wherein a hydrogenolysis catalyst is added to the subsequent formate ester to hydrogenate the formate ester to further produce methanol.   The method for producing methanol according to any one of claims 1 to 8, wherein the alcohol is a primary alcohol. A catalyst for producing methanol for use in producing a formate ester and methanol in the presence of a raw material gas containing carbon monoxide and hydrogen and an alcohol as a solvent,
Consisting of an alkali metal formate and a solid catalyst,
The catalyst for methanol production, wherein the solid catalyst comprises an alkali metal supported on a solid containing copper and alumina. The alkali metal formate is sodium formate or potassium formate;
11. The catalyst for methanol production according to claim 10, wherein sodium carbonate or sodium formate is supported on a solid made of copper and alumina.

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