JPH08245444A - Hydrogenation of carboxylic acid compound and hydrogenating catalyst therefor - Google Patents

Abstract

PURPOSE: To accomplish efficient hydrogenation in high selectivity of a carboxylic acid compound under mild conditions into a compound such as an alcohol, ether or lactone, by bringing the carboxylic acid compound into contact with hydrogen in the presence of a specific catalyst. CONSTITUTION: In the presence of (A) a catalyst prepared by carrying a group VIII noble metal component (e.g. Pd, Ru, Rh, Pt, Ir) and Re component as catalytically active components on a carrier such as a flame-retardant inorganic oxide followed by reducing at least part of the active components by a hydrous reductive gas (e.g. hydrogen 0.01-1000mg/L in moisture content) in a vapor phase, (B) a carboxylic acid compound such as maleic acid (anhydride), fumaric acid, succinic acid (anhydride) or 7-butyrolactone is brought into contact with (C) hydrogen e.g. at 130-350 deg.C under a hydrogen pressure of 1-30 MPa to accomplish hydrogenation of the component B.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a catalyst for hydrogenating carboxylic acids and a method for hydrogenating carboxylic acids using the catalyst. Specifically, the present invention is
The present invention relates to a hydrogenation catalyst for carboxylic acids containing a Group VIII noble metal and Re as a catalytically active component, and a method for hydrogenating carboxylic acids, particularly carboxylic acids having 4 carbon atoms, using the catalyst.

[0002]

2. Description of the Related Art Conventionally, carboxylic acids such as maleic acid, maleic anhydride, fumaric acid, succinic acid and succinic anhydride and carboxylic acid anhydrides are hydrogenated to produce tetrahydrofuran, 1,4-butanediol or γ-butyrolactone. Many proposals have been made regarding catalysts for doing so. Among them, as a method of using a catalyst prepared by supporting a noble metal component of group VIII of the periodic table and a Re component on a carrier, DE 2715667 discloses Pd-Re / S.
A method for producing 1,4-butanediol catalyzed by io ₂ is described, but in this case, silica obtained by the complicated operation of treating a metal silicate with acetic acid is used. In addition, in the specification of JP-A-4-500813, γ using Pd-Re-Ag / TiO ₂ as a catalyst is disclosed.
-A method for the production of butyrolactone is further described in US Pat.
No. 686 discloses a method for producing tetrahydrofuran using a catalyst in which Rh, Co, Pt and the like are added to Pd and Re and supported on activated carbon. However, although these reaction catalysts have relatively high selectivity for the alcohols and ethers to be formed, they have not yet been sufficiently satisfactory in terms of reaction activity, and neither of them is used under severe conditions of high temperature and high pressure. The reaction is taking place.

On the other hand, due to the influence of water when preparing the catalyst, Pt
Regarding Re-Al ₂ O ₃ catalyst, S.M.Augustin et al., Journal of Catalyst No. 116, p. 184 (1989) (SMAugustin
e, et al., J, Catal., 116 , 184 (1989)), and Per. Male et al., Journal of Catalyst 115, pp. 567 (1989) (P. Malet et al.,
J. Catal., 115 , 567 (1989)), and Pd-Re / Al ₂ O ₃
Regarding catalysts Journal of catalyst 99
No. 207 (1986), (SBZiemecki et al., J. Catal.,
99 , 207 (1986)). It is described that Re-O-Al bonds are formed on the surface of dehydrated Al ₂ O ₃ and that these bonds are hydrolyzed in the presence of water to make Re more mobile. ,
It is said that the reduction degree of Re is increased and the activity as a reforming catalyst is improved. The amount of water on the surface of the carrier is controlled by changing the calcination temperature of Al ₂ O ₃ for these catalysts, but there is no indication of the influence of the presence of water in the catalyst reducing atmosphere.

[0004]

In a reaction for hydrogenating carboxylic acids in the presence of a catalyst, there is provided a hydrogenation catalyst capable of efficiently advancing the hydrogenation reaction under mild conditions and selectively producing a target compound. Development is strongly desired. The present inventor has conducted extensive studies as to a method for preparing a Group VIII noble metal-Re supported catalyst, and found that a Group VIII noble metal-Re supported catalyst prepared by reduction with a reducing gas containing water in the gas phase When used to hydrogenate carboxylic acids,
The present inventors have found that the compound of interest is highly active and that the target compound can be selectively produced, and the present invention has been completed.

[0005]

The present invention provides a hydrogenation catalyst for carboxylic acids carrying a Group VIII noble metal component and a Re component in a specific method, and a method for hydrogenating carboxylic acids using the same. The gist thereof is a method for hydrogenating a carboxylic acid in the presence of a catalyst, wherein the catalyst comprises a Group VIII noble metal component and a Re component as catalytically active components supported on a carrier, and the active component A method for hydrogenating carboxylic acids, characterized in that at least a part of is obtained by a reduction treatment with a water-containing reducing gas in a gas phase, and carrying a Group VIII noble metal and Re component as a catalytically active component on a carrier, Moreover, at least a part of the active ingredient is present in a catalyst for hydrogenating carboxylic acids obtained by subjecting a reducing treatment with a hydrous reducing gas in a gas phase.

Hereinafter, the present invention will be described in detail. still,
In the present specification, the carboxylic acids include carboxylic acids, carboxylic acid anhydrides including intramolecular anhydrides of polycarboxylic acids, and carboxylic acid esters including intramolecular esters such as lactones. The carboxylic acids used in the hydrogenation reaction in the present invention are not particularly limited as long as they can be catalytically reduced using the catalyst according to the present invention. Specifically, for example, acetic acid, caproic acid,
Caprylic acid, undecenoic acid, lauric acid, myristic acid, palmitic acid, stearic acid, isostearic acid,
Carboxylic acid anhydrides such as oleic acid, oxalic acid, maleic acid, adipic acid, sebacic acid, benzoic acid, fumaric acid, succinic acid and other aliphatic or aromatic mono-, dicarboxylic acids, succinic anhydride, maleic anhydride, etc. It is illustrated. Also, esters of these carboxylic acids may be used, and the alcohol constituting the ester portion is not particularly limited, but lower alcohols having about 1 to 5 carbon atoms such as methanol and ethanol are preferable. Furthermore, lactones such as γ-butyrolactone which is an intramolecular ester are also preferably used.

In the present invention, among these, particularly, the number of carbon atoms is 1 to 1.
15 aliphatic monocarboxylic acid or 4 to 6 carbon atoms
The dicarboxylic acid or the acid anhydride thereof is preferably used, and more preferably a dicarboxylic acid having 4 carbon atoms, particularly maleic acid and its acid anhydride. The hydrogenated product according to the present invention is mainly alcohols, lactones, cyclic ethers, etc., although it varies depending on the kind of carboxylic acid as a starting material. When the dicarboxylic acid having 4 carbon atoms is subjected to the hydrogenation reaction according to the present invention, γ-butyrolactone, tetrahydrofuran or the like is obtained as a hydrogenation product in addition to the corresponding 1,4-butanediol. The catalyst prepared according to the present invention described below can change the composition of the hydrogenation reaction product depending on its acidity. For example, when the acidity is higher, mainly tetrahydrofuran and γ-butyrolactone are produced,
The production of 1,4-butanediol is small. On the other hand, when the acidity is lower, the production rate of 1,4-butanediol is increased.

In the catalyst of the present invention, the noble metal component of Group VIII and the V component which are the raw materials of the Re component constituting the catalyst component
The Group III noble metal compound and rhenium compound are not particularly limited as long as they can be decomposed by heating. Examples of the Group VIII noble metal component include metals such as palladium, ruthenium, rhodium, platinum and iridium and compounds thereof, and these may be used alone or in combination of two or more kinds. As the palladium compound, palladium chloride, palladium nitrate, inorganic salts such as palladium sulfate,
Examples thereof include organic compounds such as palladium acetate and palladium acetylacetonate, and coordination compounds such as tetraammine palladium chloride. As ruthenium compounds, ruthenium chloride, inorganic salts such as ruthenium nitrosyl nitrate,
Examples thereof include organic compounds such as ruthenium acetylacetonate, coordination compounds such as pentaammine ruthenium chloride, and triruthenium dodecacarbonyl.Examples of rhodium compounds include inorganic salts such as rhodium chloride, rhodium nitrate, and rhodium sulfate, rhodium acetylacetate. Examples thereof include organic compounds such as natrium, and coordination compounds such as tetrarhodium dodecacarbonyl.

As the platinum compound, chloroplatinic acid,
Acids such as sodium chloroplatinate and inorganic salts, organic compounds such as platinum acetylacetonate, coordination compounds such as tetraammineplatinium chloride, and the like, examples of iridium compounds include iridium chloride, iridium chloride and other acids and acids. Examples thereof include inorganic salts, organic compounds such as iridium acetylacetonate, and coordination compounds such as tetriridium dodecacarbonyl. Of these Group VIII noble metal compounds, palladium compounds are particularly preferably used.

Examples of the rhenium compound include inorganic salts such as dirhenium heptaoxide, perrhenic acid, ammonium perrhenate and rhenium chloride, acids, and coordination compounds such as dirhenium decacarbonyl.

The amount of the catalytic metal component supported is not particularly limited, but if the amount is small, a sufficient catalytic effect cannot be achieved, and conversely, if the amount is too large, it is disadvantageous in cost. Therefore, in general, the catalyst contains the Group VIII noble metal as a metal in an amount of 0.1 to 20% by weight, preferably 1 to 20% by weight, based on the total weight of the catalyst.
It is desirable to contain 10% by weight and 0.1 to 20% by weight of rhenium, preferably 0.1 to 10% by weight.

The carrier used for supporting the above-mentioned catalytically active component of the catalyst of the present invention is carbon carrier containing carbon as a main component such as carbon black, graphite, activated carbon, or silica, alumina, silica-alumina, titania, zirconia. , A flame-retardant inorganic oxide carrier such as zeolite, and the like, but silica is more preferable because it has high activity and is stable in an acidic solution.

The order of steps for producing the catalyst of the present invention is not particularly limited, and examples thereof include the following methods. 1) A carrier is simultaneously impregnated with a solution of a Group VIII noble metal compound and a rhenium compound and, if necessary, under reduced pressure, usually 50
A method of performing reduction after drying at -200 ° C. 2) A method of impregnating a carrier with a Group VIII noble metal compound, optionally drying under reduced pressure usually at 50 to 200 ° C., then reducing, then impregnating with a rhenium compound, drying and reducing. 3) A Group VIII noble metal component is supported on a carrier by an ion exchange method, and if necessary, dried under reduced pressure, usually at 50 to 200 ° C., and then reduced, then impregnated with a rhenium component, dried, and reduced. Method. 4) A method in which the Group VIII noble metal compound, the rhenium compound and the carrier are physically and thoroughly mixed, and then dried under reduced pressure, if necessary, usually at 50 to 200 ° C., and then reduced.

In the above-mentioned preparation method, it is preferable that the Group VIII noble metal and / or the drying after the Re is carried out is carried out under the condition that the metal component and the carrier do not form a non-reducing substance. Generally, the metal component-carrier hardly reducible substance is produced when treated at a higher temperature, and therefore, when drying is performed, it is preferable to perform the drying at 200 ° C. or lower as described above. The ion exchange method described in 3) above is usually carried out under a basic condition using a cation complex of a Group VIII noble metal. In addition, the noble metal compound of Group VIII and the rhenium compound may be supported on the carrier in multiple stages depending on the case, and the reduction process may be appropriately combined therewith.

In the present invention, when the catalyst is prepared, it is necessary to reduce the catalyst metal component in the gas phase by using a reducing gas containing water or a gas obtained by diluting the reducing gas with an inert gas. Hydrogen, carbon monoxide, and the like are used as the reducing gas, but hydrogen is preferable in consideration of activity and handleability. Helium, nitrogen, argon or the like is used as the inert gas, and the concentration of the reducing gas is 2 to 99% by volume,
20 to 80% by volume is suitable.

The amount of water contained in the reducing gas is 0.01
mg / l to 1 g / l, preferably 0.05 mg / l to
0.9 g / l, more preferably 0.1 mg / l to 0.8
g / l is suitable. If the water content exceeds this range and is too low or too high, high catalytic activity and selectivity are not achieved, which is not preferable.

In preparing the catalyst of the present invention,
When the group I noble metal component and the rhenium component are sequentially supported on the carrier, for example, a) the reduction after the first-stage group VIII noble metal component is carried out is performed using ordinary dry hydrogen, and A method in which the second-stage reduction is carried out with hydrogen containing water, b) the reduction after the first-stage Group VIII noble metal component loading is carried out with hydrogen containing water, and the second-stage rhenium component loading is carried out A subsequent reduction with dry hydrogen, or c)
The reduction after the first-stage Group VIII noble metal component is supported and the second-stage reduction after the rhenium component is supported can be carried out by a method in which hydrogen containing water is used. Although the activity is improved as compared with the case of treatment with a non-reducing gas, it is particularly preferable to perform both reduction treatments using a water-containing reducing gas among these methods. The reduction temperature is not particularly limited as long as the catalyst raw material compound is reduced to a metal, but it is usually carried out at a temperature of 30 to 500 ° C. for usually several minutes to several hours. Upon reduction treatment for catalyst activation,
Since the reduction of the rhenium compound is promoted by the Group VIII noble metal such as Pd and Pt, it is desirable to reduce the rhenium compound in the coexistence of both component compounds.

Although the details of the effect of water contained in the reducing gas are not clear, water is added when the mobility of Re on the carrier is increased to improve the reduction degree or when the noble metal component compound is decomposed. The presence of the above causes a change in the surface area, particle size, crystal shape of the metal, etc., and these act individually or in combination to form a more effective catalyst metal supporting state and achieve high activity. it is conceivable that.

In the present invention, the carboxylic acids are hydrogenated using the catalyst prepared as described above.
Usually, the temperature is 130 to 350 ° C, preferably 160 to 30
0 ° C, hydrogen pressure 1-30MPa, preferably 5-20MP
It is performed in the range of a. The amount of the catalyst used in the hydrogenation reaction is 0.1 with respect to 100 parts by weight of the reaction raw material such as carboxylic acid.
It is desirable that the amount is ˜100 parts by weight, but it is arbitrarily selected within the range where a practical reaction rate can be obtained according to various conditions such as reaction temperature or reaction pressure. Further, as described above, since the composition of the hydrogenation reaction product can be changed depending on the acidity of the catalyst, an alkali such as lithium hydroxide is appropriately supported on the catalyst depending on the target product. Alternatively, it may be added to the reaction raw material solution to control the acidity of the catalyst. In that case, the amount of the alkali used is 0.1 to 100 with respect to 100 parts by weight of the catalyst.
Parts by weight, preferably 1 to 50 parts by weight.

The hydrogen used in the hydrogenation reaction has a purity which is usually used industrially, but hydrogen diluted with an inert gas such as nitrogen may also be used as the case may be. In addition, the amount used is generally in excess of the stoichiometric amount with respect to the starting carboxylic acid.

As the reaction system, either a liquid phase suspension bed or a fixed bed can be adopted. In the case of a suspension bed, the separation of the catalyst and the reaction solution after completion of the reaction can be easily performed by a commonly used method such as decantation or filtration. In the continuous method, for example, a trickle bed method is used, and the raw material carboxylic acids are supplied to the reaction zone as a melt or a solution. Purification and separation of the desired product from the obtained reaction solution can be easily performed by a method usually used in industry, such as distillation. Further, in the case of recycling the separated / collected catalyst, activation of the catalyst can be effectively achieved by performing a reduction treatment with a reducing gas containing water.

The hydrogenation reaction may be carried out without a solvent,
A reaction solvent may be used if necessary. When a solvent is used, the solvent is not particularly limited as long as it does not adversely affect the reaction, and specifically, water, methanol, ethanol, octanol, dodecanol, alcohols such as ethylene glycol; tetrahydrofuran,
Ethers such as dioxane and tetraethylene glycol dimethyl ether; and hydrocarbons such as hexane, cyclohexane and decalin.

[0023]

EXAMPLES The present invention will be described in more detail below with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples unless it exceeds the gist. In the examples and comparative examples,% means% by weight.

Example 1 33.3 mg of palladium chloride and dirhenium heptoxide 7
Dissolve 8 mg in 2 ml of hydrochloric acid aqueous solution, and add SiO
₂ (Fuji Davison Grade 12) (1.92 g) was added and impregnated, and then water was distilled off with a rotary vacuum dryer. Then, it is dried at 100 ° C. for 2 hours in a vacuum, and the dried product 0.2
2 g under a hydrogen atmosphere containing 12.1 mg / l of water, 30
Reduction was performed at 0 ° C. for 2 hours to obtain a 1% Pd-3% Re / SiO ₂ catalyst. 2 g of maleic anhydride was dissolved in 8 g of water, charged into a 70 ml spinner stirring type autoclave together with the catalyst prepared by the above method, hydrogen of 10 MPa was injected at room temperature, and the reaction was carried out at 240 ° C. for 2 hours. The results of gas chromatography analysis of the reaction product are shown in Table 1.

Example 2 33.3 mg of palladium chloride and dirhenium heptoxide 7
Dissolve 8 mg in 2 ml of hydrochloric acid aqueous solution, and add SiO
₂ (Fuji Davison Grade 12) (1.92 g) was added and impregnated, and then water was distilled off with a rotary vacuum dryer. Then, it is dried at 100 ° C. for 2 hours in a vacuum, and the dried product 0.2
30 g of 2 g under a hydrogen atmosphere containing 19.0 mg / l of water.
Reduction was performed at 0 ° C. for 2 hours to obtain a 1% Pd-3% Re / SiO ₂ catalyst. A hydrogenation reaction of maleic anhydride was performed in the same manner as in Example 1 except that the obtained catalyst was used. The results are shown in Table-1.

Comparative Example 1 33.3 mg of palladium chloride and dirhenium heptoxide 7
Dissolve 8 mg in 2 ml of hydrochloric acid aqueous solution, and add SiO
₂ (Fuji Davison Grade 12) (1.92 g) was added and impregnated, and then water was distilled off with a rotary vacuum dryer. Then, it is dried at 100 ° C. for 2 hours in a vacuum, and the dried product 0.2
Reduce 2g at 300 ° C for 2 hours under dry hydrogen atmosphere to 1
% Pd-3% Re / SiO ₂ catalyst was obtained. Using this catalyst, a hydrogenation reaction of maleic anhydride was carried out in the same manner as in Example 1. The results are shown in Table-1.

[0027]

[Table 1]

Example 3 Palladium chloride 100 mg and dirhenium heptaoxide 78
mg was dissolved in 2 ml of an aqueous solution of hydrochloric acid, and SiO 2 was added to this.
₂ (Fuji Davison Grade 12) (1.88 g) was added for impregnation, and then water was distilled off with a rotary vacuum dryer.
Thereafter, the product was dried in vacuum at 100 ° C. for 2 hours to give a dried product of 0.
22 g under a hydrogen atmosphere containing 27.6 mg / l of water, 3
3% Pd-3% Re / SiO _{2 after} reduction at 00 ° C. for 2 hours
A catalyst was obtained. The hydrogenation reaction of maleic anhydride was carried out in the same manner as in Example 1 except that this catalyst was used. Table of results
Shown in 2.

Comparative Example 2 Palladium chloride 100 mg and dirhenium heptoxide 78
mg was dissolved in 2 ml of an aqueous solution of hydrochloric acid, and SiO 2 was added to this.
₂ (Fuji Davison Grade 12) (1.88 g) was added for impregnation, and then water was distilled off with a rotary vacuum dryer.
Thereafter, the product was dried in vacuum at 100 ° C. for 2 hours to give a dried product of 0.
22 g was reduced in a dry hydrogen atmosphere at 300 ° C. for 2 hours to obtain a 3% Pd-3% Re / SiO ₂ catalyst. Using the obtained catalyst, a hydrogenation reaction of maleic anhydride was carried out in the same manner as in Example 1. The results are shown in Table-2.

[0030]

[Table 2]

Example 4 250 mg of palladium chloride was added to 1.91 ml of 5N hydrochloric acid.
After adding 4.7 g of SiO ₂ (Grade 12 manufactured by Fuji Devison Co., Ltd.) to the solution dissolved in the above solution to impregnate it, water was distilled off with a rotary vacuum dryer. Then, it was dried in vacuum at 100 ° C. for 2 hours, and then reduced at 300 ° C. for 2 hours in a hydrogen atmosphere containing 12.1 mg / l of water to obtain Pd / SiO ₂ . 78 mg of Re ₂ O ₇ was dissolved in 0.79 ml of water, and this was added to 1.94 g of Pd / SiO ₂ prepared above to impregnate it, and the water was distilled off with a rotary vacuum dryer. Then, it was dried at 100 ° C. for 2 hours in vacuum, and 0.22 g of the dried product was reduced at 300 ° C. for 2 hours under a dry hydrogen atmosphere to obtain 3% Pd-.
A 3% Re / SiO ₂ catalyst was obtained. The same procedure as in Example 1 was carried out using the catalyst obtained by the hydrogenation reaction of maleic anhydride. The results are shown in Table-3.

Example 5 250 mg of palladium chloride was added to 1.91 ml of 5N hydrochloric acid.
Was dissolved in water, and 4.7 g of SiO ₂ (Grade 12 manufactured by Fuji Davison Co., Ltd.) was added thereto for impregnation, and then water was distilled off with a rotary vacuum dryer. After that, it was dried in vacuum at 100 ° C. for 2 hours and then reduced at 300 ° C. for 2 hours in a dry hydrogen atmosphere to obtain Pd / SiO ₂ . 78 mg of Re ₂ O ₇ was dissolved in 0.79 ml of water, and this was dissolved in Pd / SiO ₂ 1.9.
After adding 4 g and impregnating, water was distilled off with a rotary vacuum dryer. Then, it is dried at 100 ° C. for 2 hours in a vacuum, and 0.22 g of the dried product is reduced at 300 ° C. for 2 hours under a hydrogen atmosphere containing 25.9 mg / l of water to give 3% Pd-3% Re / S.
An iO ₂ catalyst was obtained. Using this catalyst, the hydrogenation reaction of maleic anhydride was carried out in the same manner as in Example 1. Table of results
3 is shown.

Example 6 250 mg of palladium chloride was added to 1.91 ml of 5N hydrochloric acid.
Was dissolved in water, and 4.7 g of SiO ₂ (Grade 12 manufactured by Fuji Davison Co., Ltd.) was added thereto for impregnation, and then water was distilled off with a rotary vacuum dryer. Then, it was dried in vacuum at 100 ° C. for 2 hours and then reduced at 300 ° C. for 2 hours in a hydrogen atmosphere containing 12.1 mg / l of water to obtain Pd / SiO ₂ .
78 mg of Re ₂ O ₇ was dissolved in 0.79 ml of water, and this was added to 1.94 g of Pd / SiO ₂ obtained above to impregnate it, and then water was distilled off with a rotary vacuum dryer. After that, it is dried in vacuum at 100 ° C. for 2 hours, and 0.22 g of the dried product is added to 4
2 at 300 ° C. under a hydrogen atmosphere containing 4.8 mg / l of water.
It was reduced for a time to obtain a 3% Pd-3% Re / SiO ₂ catalyst. Using the obtained catalyst, a hydrogenation reaction of maleic anhydride was carried out in the same manner as in Example 1. The results are shown in Table-3.

Comparative Example 3 250 mg of palladium chloride was added to 1.91 ml of 5N hydrochloric acid.
Was dissolved in water, and 4.7 g of SiO ₂ (Grade 12 manufactured by Fuji Davison Co., Ltd.) was added thereto for impregnation, and then water was distilled off with a rotary vacuum dryer. After that, it was dried in vacuum at 100 ° C. for 2 hours and then reduced at 300 ° C. for 2 hours in a dry hydrogen atmosphere to obtain Pd / SiO ₂ . 78 mg of Re ₂ O ₇ was dissolved in 0.79 ml of water to obtain Pd / SiO ₂
In addition to 1.94 g, the solution was impregnated and water was distilled off with a rotary vacuum dryer. After that, dry in vacuum at 100 ° C for 2 hours,
0.22 g of the dried product was reduced in a dry hydrogen atmosphere at 300 ° C. for 2 hours to obtain a 3% Pd-3% Re / SiO ₂ catalyst.
Using this catalyst, hydrogenation reaction of maleic anhydride was carried out in the same manner as in Example 1. The results are shown in Table-3.

[0035]

[Table 3]

[0036]

EFFECTS OF THE INVENTION According to the present invention, a catalyst carrying a noble metal component of Group VIII and a Re component which has been subjected to reduction treatment under specific conditions has extremely high activity and selectivity. When hydrogenated, the desired products such as alcohols, ethers and lactones can be efficiently produced under mild conditions as compared with conventional reaction conditions.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C07D 307/08 C07B 61/00 300 307/33 B01J 23/64 104Z // C07B 61/00 300 C07D 307/32 F

Claims (13)

[Claims] 1. A method for hydrogenating carboxylic acids in the presence of a catalyst, wherein the catalyst is a VI active ingredient.
A Group II precious metal component and a Re component are supported on a carrier,
A method for hydrogenating carboxylic acids, characterized in that at least a part of the active ingredient is obtained by reduction treatment with a hydrous reducing gas in a gas phase. 2. The method for hydrogenating carboxylic acids according to claim 1, wherein hydrogen is used as the reducing gas. 3. The water content of the reducing gas is 0.01 mg /
The method for hydrogenating carboxylic acids according to claim 1, characterized in that the range is from 1 to 1 g / l. 4. A carrier is loaded with a Group VIII noble metal component for reduction treatment, and then a Re component is loaded for reduction treatment.
The method for hydrogenating a carboxylic acid according to any one of claims 1 to 3, wherein at least one of the reduction treatments is performed with a water-containing reducing gas. 5. The carboxylic acids include maleic anhydride, maleic acid, fumaric acid, succinic anhydride, succinic acid, and γ-.
The method for hydrogenating carboxylic acids according to claim 1, which comprises at least one selected from butyrolactone. 6. The reaction temperature of carboxylic acids is 130 to 350.
The method for hydrogenating carboxylic acids according to claim 1, wherein hydrogenation is carried out at a temperature of 1 ° C and a hydrogen pressure of 1 to 30 MPa. 7. A method for producing tetrahydrofuran and / or γ-butyrolactone by hydrogenating maleic acid and / or maleic anhydride by the method according to claim 1. 8. A noble metal of Group VIII and a Re component as a catalytically active component are supported on a carrier, and at least a part of the active component is obtained by reduction treatment with a hydrous reducing gas in a gas phase. A catalyst for hydrogenating carboxylic acids, characterized by: 9. The Group VIII noble metal component is Pd, Ru,
9. The hydrogenation catalyst according to claim 8, containing at least one selected from the group consisting of Rh, Pt and Ir. 10. A carrier is loaded with a Group VIII noble metal component to carry out a reduction treatment, then a Re component is carried to carry out a reduction treatment, and at least one of the reduction treatments is carried out with a hydrous reducing gas. The hydrogenation catalyst according to claim 8. 11. The hydrogenation catalyst according to claim 8, wherein hydrogen is used as the reducing gas. 12. The water content of the reducing gas is 0.01 mg.
9. The range from 1 / g to 1 g / l.
The hydrogenation catalyst according to any one of 1 to 11. 13. The hydrogenation catalyst according to claim 8, wherein the carrier is a flame-retardant inorganic oxide.