KR20250041124A - Metal-supported catalyst, method for producing alcohol and method for hydrogenation - Google Patents

Abstract

A metal-supported catalyst for hydrogenation of a carboxylic acid and/or a carboxylic acid ester, wherein ruthenium, tin and platinum are supported on a support, wherein the metal-supported catalyst is further supported with iron, and chromium and/or molybdenum. The present invention provides a catalyst having a lower by-product yield while maintaining high catalytic activity, and a method for producing alcohol from a carboxylic acid and/or a carboxylic acid ester using the catalyst, and a method for hydrogenating a carboxylic acid and/or a carboxylic acid ester.

Description

Metal-supported catalyst, method for producing alcohol and method for hydrogenation

The present invention relates to a metal-supported catalyst, and more particularly, to a metal-supported catalyst capable of hydrogenating a carboxylic acid and/or a carboxylic acid ester with high selectivity, a method for producing an alcohol using the metal-supported catalyst, and a hydrogenation method.

As a catalyst for reducing carboxylic acids and/or carboxylic acid esters to corresponding alcohols, a catalyst has been proposed in which ruthenium, tin and platinum are supported on a carrier and the carrier is reduced with hydrogen or the like (e.g., Patent Documents 1 and 2). This catalyst exhibits high reaction activity and reaction selectivity in the hydrogenation of carboxylic acids and/or carboxylic acid esters, and is a good catalyst.

In addition, patent document 3 discloses a catalyst in which iron is additionally supported on a reduction catalyst. More specifically, a supported catalyst in which nitrates of iron, cobalt, and nickel are added to a reduction catalyst in which ruthenium, platinum, and tin are supported as main component metals is disclosed, and production of 1,4-cyclohexanedimethanol is disclosed.

Japanese Patent Publication No. 2001-9277 International Publication No. 2015/178459 Chinese Patent Specification No. 104722321

When a hydrogenation reaction of a carboxylic acid and/or a carboxylic acid ester is performed using a catalyst described in previously known patent documents 1 and 2, although the hydrogenation activity is high, by-products accompanied by cleavage of C-C bonds and C-O bonds are generated, so that the yield of the desired product is reduced, and in some cases, precise manipulation for removal of the by-products becomes necessary.

The catalyst disclosed in patent document 3 suppresses the production of by-products compared to the catalysts described in patent documents 1 and 2, but the degree is insufficient, and further improvement is desired.

In consideration of the above circumstances, the present invention aims to provide a catalyst having a lower by-product yield while maintaining high catalytic activity.

The present inventors have found that a metal-supported catalyst comprising ruthenium, tin and platinum supported on a carrier, and additionally supporting iron, and chromium and/or molybdenum, can significantly reduce the yield of by-products while maintaining high catalytic activity.

Although the details are not clear, it is presumed that iron, chromium, and molybdenum exhibit the effect of selectively inhibiting the active sites that cleave C-C bonds and C-O bonds, rather than the active sites that reduce carbonyl on the catalyst, and in particular, it was found that the above effect can be significantly exhibited by a combination of iron and chromium, a combination of iron and molybdenum, and further by a combination of the three components of iron, chromium, and molybdenum.

The gist of the present invention is as follows.

[1] A metal-supported catalyst used for the hydrogenation of a carboxylic acid and/or a carboxylic acid ester, wherein the metal-supported catalyst further comprises iron, and chromium and/or molybdenum supported on a support.

[2] The metal-supported catalyst described in [1] above, wherein the amount of iron supported is 0.01 mass% or more and 4 mass% or less with respect to the total mass of the metal-supported catalyst, and further, the total amount of chromium and/or molybdenum supported is 0.01 mass% or more and 2 mass% or less.

[3] A metal-supported catalyst as described in [1] or [2], wherein the support is a carbonaceous support.

[4] A metal-supported catalyst according to any one of [1] to [3] above, wherein the total supported amount of ruthenium, tin, platinum, iron, molybdenum, and chromium is 5 mass% or more based on the total mass of the metal-supported catalyst.

[5] A metal-supported catalyst according to any one of [1] to [4], wherein the metal-supported catalyst is prepared through hydrogen reduction.

[6] A method for producing alcohol, comprising contacting a carboxylic acid and/or a carboxylic acid ester with a metal-supported catalyst as described in any one of [1] to [5] to perform reduction, thereby obtaining an alcohol corresponding to each of the carboxylic acid and/or the carboxylic acid ester.

[7] A method for hydrogenating a carboxylic acid and/or a carboxylic acid ester, comprising contacting the carboxylic acid and/or the carboxylic acid ester with a metal-supported catalyst as described in any one of [1] to [5].

[8] A method for producing an alcohol as described in [6], wherein the carboxylic acid is 1,4-cyclohexanedicarboxylic acid and the carboxylic acid ester is an ester of 1,4-cyclohexanedicarboxylic acid.

According to the present invention, it is possible to provide a catalyst having a lower by-product yield while maintaining high catalytic activity, a method for producing alcohol from a carboxylic acid and/or a carboxylic acid ester using the catalyst, and a method for hydrogenating a carboxylic acid and/or a carboxylic acid ester.

Hereinafter, embodiments of the present invention will be described in detail, but the description of the constituent elements described below is an example (representative example) of embodiments of the present invention, and the present invention is not limited to these contents, and can be implemented by making various modifications within the scope of the gist thereof.

In addition, in this invention, the metal (ruthenium, tin, platinum, iron, etc. used as needed) supported on a carrier may be collectively referred to as a "metal component." In addition, the metal component supported on a carrier, the metal component subjected to reduction treatment, and the metal component subjected to oxidation stabilization treatment may be collectively referred to as a "metal-supported catalyst." In addition, the metal component additionally supported on the "metal-supported catalyst" that has undergone such oxidation stabilization treatment may also be referred to as a "metal-supported catalyst." In addition, in the metal-supported catalyst, the catalyst before the reduction treatment may be referred to as a "metal-supported substance."

[Metal Supported Catalyst]

The metal-supported catalyst of the present invention (hereinafter, sometimes simply referred to as “the present catalyst”) is obtained by reducing a metal-supported material in which the metal component is supported on a carrier, usually by a reducing gas. In addition, a catalyst obtained by oxidizing the metal-supported catalyst subjected to the reduction treatment is also included in the metal-supported catalyst of the present invention. In addition, a catalyst in which a metal component is additionally added after performing these treatments is also included in the metal-supported catalyst.

The metal-supported catalyst of the present invention is a catalyst containing ruthenium, tin, and platinum as essential elements (hereinafter, sometimes referred to as a "reduction catalyst"), wherein the reduction catalyst is further supported with iron, and chromium and/or molybdenum. Specifically, there are embodiments of a combination of iron and chromium, a combination of iron and molybdenum, and a combination of three components of iron, chromium, and molybdenum. By using a metal-supported catalyst having such a configuration, the yield of by-products accompanied by cleavage of C-C bonds and C-O bonds can be further suppressed while maintaining hydrogenation activity.

For example, when 1,4-cyclohexanedicarboxylic acid is hydrogenated as a carboxylic acid, cyclohexanemethanol involving C-C cleavage and 4-methylcyclohexanemethanol involving C-O cleavage are generated as by-products along with the target product, 1,4-cyclohexanedimethanol, thereby reducing the yield of the target product. In this regard, by using the catalyst of the present invention, the generation of by-products can be effectively suppressed.

In addition, 1,4-cyclohexanedimethanol, a diol compound, is often used as a raw material for resins such as polyester and polyurethane. In such cases, monoalcohols such as cyclohexanemethanol and 4-methylcyclohexanemethanol act as polymerization terminators, so their mixing must be avoided during resin synthesis, and a removal operation becomes necessary. On the other hand, if the amount of by-products produced in the hydrogenation reaction is reduced, there is an advantage in that the purification operation for removing the monoalcohol can be simplified or skipped.

<Carrier>

The carrier used in the present invention is not particularly limited as long as it has a large surface area and can support a metal component, and examples thereof include carbonaceous carriers such as activated carbon and carbon black; inorganic porous carriers such as alumina, silica, diatomaceous earth, zirconia, titania, and hafnia; silicon carbide, gallium nitride, and the like. Among these, carbonaceous carriers such as activated carbon, graphite, and graphite, titania, and zirconia are preferable, and carbonaceous carriers are more preferable in terms of excellent stability and ease of industrial acquisition, and activated carbon is even more preferable in that it has a high surface area, excellent metal dispersibility, and easily increases reaction activity. In addition, it does not matter whether one type of carrier is used or two or more types are used in combination.

The carrier may be used as is, or may be used after being pretreated into a form suitable for the carrier. For example, in the case of using a carbonaceous carrier, as described in Japanese Patent Application Laid-Open No. (H) 10-71332, the carbonaceous carrier may be used after being heat-treated with nitric acid. By the above method, the dispersion of the metal component on the carrier can be improved, and the activity of the resulting catalyst is improved.

The shape and size of the carrier used in the present invention are not particularly limited, but when the shape is converted to a spherical shape, the average primary particle diameter is usually 50 μm or more and 5 mm or less, and preferably 4 mm or less. In addition, the particle diameter is measured by the sieve test method described in JIS standard JIS Z8815.

Since the very suitable particle diameter of the carrier varies depending on the reaction using the present catalyst, it is preferable to adjust it depending on the reaction. Specifically, when the reaction using the present catalyst is a complete mixing reaction, the particle diameter of the carrier is usually 50 μm or more, preferably 100 μm or more, and usually 3 mm or less, preferably 2 mm or less. The smaller the particle diameter of the carrier, the higher the activity per unit mass of the obtained catalyst, which is preferable, but if it becomes too small, separation of the reaction solution and the catalyst may become difficult. That is, when the particle diameter of the carrier is equal to or greater than the above lower limit, it is preferable from the viewpoint of reaction activity, and when it is equal to or less than the above upper limit, it is preferable because separation from the reaction solution is easy.

In addition, if the shape of the carrier is not spherical, the volume of the carrier is calculated and converted into the diameter of a spherical particle of the same volume.

In addition, when the reaction using the present catalyst is a fixed-bed reaction, the particle diameter of the carrier is usually 0.5 mm or more and 5 mm or less, preferably 4 mm or less, and more preferably 3 mm or less. When it is equal to or greater than the lower limit, operation does not become difficult due to differential pressure, and when it is equal to or less than the upper limit, sufficient reaction activity is obtained.

<Metal components>

The metal-supported catalyst of the present invention is a catalyst in which ruthenium, tin, and platinum are supported on a support as essential elements, and the catalyst is further supported with iron, and chromium and/or molybdenum (hereinafter sometimes referred to as “other metals such as iron”). By additionally supporting iron, chromium, and/or molybdenum, the production of by-products can be further suppressed. The effect of suppressing the production of by-products is further enhanced by supporting iron, chromium, and/or molybdenum.

In addition, in addition to ruthenium, tin, platinum, iron, chromium, and molybdenum, the catalyst may additionally contain other metals as needed, as long as they do not adversely affect reactions such as reduction reactions using the catalyst, and preferably contains at least one metal selected from metals such as rhodium, tungsten, rhenium, barium, and boron, and more preferably contains rhenium.

Additionally, the raw materials for each metal component are described below.

(Metal component loading)

The amount of the metal component of the present catalyst supported is not particularly limited and is determined for each metal. The amount of ruthenium supported is usually 1 mass% or more, preferably 3 mass% or more, usually 10 mass% or less, and preferably 8 mass% or less, in mass ratio with respect to the total mass of the metal-supported catalyst. Similarly, the amount of tin supported is usually 1 mass% or more, preferably 2 mass% or more, usually 15 mass% or less, and preferably 10 mass% or less, in mass ratio with respect to the total mass of the metal-supported catalyst. In addition, similarly, the amount of platinum supported is usually 0.5 mass% or more, usually 7 mass% or less, and preferably 5 mass% or less, in mass ratio with respect to the total mass of the metal-supported catalyst. This is preferable because the ability as a hydrogenation catalyst is enhanced by setting it within these ranges. In addition, the amounts of iron, chromium, and/or molybdenum supported are preferably 0.01 mass% or more and 4 mass% or less, and more preferably 2 mass% or less, respectively. By setting it in this range, the generation of by-products can be significantly reduced. That is, the amount of iron supported is preferably 0.01 mass% or more and 4 mass% or less, and more preferably 0.01 mass% or more and 2 mass% or less. The amount of chromium and/or molybdenum supported, when either one is supported, is in the range of a very suitable amount of each metal supported, preferably 0.01 mass% or more and 4 mass% or less, and more preferably 0.01 mass% or more and 2 mass% or less. When both chromium and molybdenum are supported, it is preferable that the total supported amount of both is in the above range. In addition, in order to sufficiently obtain the by-product suppression effect by the combined use of iron and chromium, the composition ratio is not particularly limited as long as it is in the above range, but, for example, 100:1 to 1:100 is used, more preferably 10:1 to 1:10, and even more preferably 10:1 to 1:5. Also, in the case of combined use of iron and molybdenum, the same range is desirable. On the other hand, since chromium and molybdenum are more expensive than iron in terms of cost, it is desirable to use less than iron in this sense.

The total supported amount of other metals such as ruthenium, tin, platinum and iron relative to the total mass of the metal-supported catalyst is not particularly limited, but is usually 5 mass% or more, preferably 8 mass% or more, more preferably 10 mass% or more, and usually 40 mass% or less, preferably 30 mass% or less, more preferably 20 mass% or less.

In addition, the amount of the metal supported is a value obtained by converting all of the supported metals into metal atoms. In addition, the size of the metal-supported catalyst after reduction of the present invention is not particularly limited, but is basically the same as the size of the support described above.

In addition, the amount of the supported metal (hereinafter sometimes referred to as "metal") can be measured, for example, by the following method. The catalyst can be powdered and stirred to make it uniform, and, if necessary, made into a disk, and analyzed in a solid state by fluorescent X-ray analysis. Alternatively, it can be made into a uniform solution after alkaline melting decomposition or microwave pressurized decomposition, and analyzed by ICP emission spectrometry (inductively coupled plasma emission spectrometry).

Among these, the preferred method is ICP emission spectrometry (inductively coupled plasma emission spectrometry) because it provides more precise measurement results by using a homogeneous solution.

<Method for manufacturing catalyst>

In the present invention, the method for manufacturing a catalyst includes a step of supporting the metal component on a carrier (hereinafter referred to as a metal supporting step), followed by a step of reducing the obtained metal supporting material with a reducing gas. The steps are described in order below.

<<Metal Support Process>>

The metal loading process is a process of obtaining a metal loading material by loading the metal component on the above-mentioned carrier. The method of loading the metal component is not particularly limited, and a known method can be used. When loading, a solution or dispersion of various metal compounds that are raw materials for the metal component can be used.

(Metal support method)

The method for supporting the metal component on the carrier is not particularly limited, but various impregnation methods can usually be applied. For example, there are an adsorption method in which metal ions less than the saturation adsorption amount are adsorbed by utilizing the adsorption power of metal ions on the carrier, an equilibrium adsorption method in which the carrier is immersed in a solution of metal ions greater than the saturation adsorption amount and the excess solution is removed, a pore filling method in which a metal ion solution in an amount equal to the pore volume of the carrier is added and the entire solution is adsorbed on the carrier, an incipient wetness method in which a metal ion solution is added until it is suitable for the absorption amount of the carrier and the process is completed in a state where the surface of the carrier is uniformly wet but no excess solution exists, an evaporation-to-drying method in which a metal ion solution is impregnated into the carrier and the solvent is evaporated while stirring, and a spraying method in which a solution is sprayed while the carrier is in a dry state.

Among the above methods, the pore peeling method, the incipient wetness method, the evaporation to dryness method, and the spraying method are preferable, and the pore peeling method, the incipient wetness method, and the evaporation to dryness method are more preferable. By the above methods, ruthenium, tin, platinum, and other metal components such as iron can be supported in a relatively uniformly dispersed state.

The support may be carried out all at once after preparing the entire metal solution to be supported, or may be carried out in sections by metal. In addition, in the case of sectioned support, the support may be carried out in sections by type, or may be carried out in sections by metal solutions of multiple types. In terms of shortening the support process, it is preferable to support the entire metal solution all at once, or to carry out sectioned support by multiple types of metals. The timing of sectioned support is not particularly limited, and multiple types of metals may be simply supported in sections by several times, or sectioned support may be carried after supporting up to the hydrogen reduction process, or sectioned support may be carried on the metal support catalyst after hydrogen reduction.

(metal compound)

There is no particular limitation on the metal compound used for the support, and it can be appropriately selected depending on the support method. For example, halides such as chloride, bromide, and iodide; mineral salts such as nitrate and sulfate; organic salts such as acetate; metal hydroxides, metal oxides, organometallic compounds, and metal complexes can be used. Among these, halides, mineral salts, and organic salts are preferable, halides and mineral salts are more preferable, and it is even more preferable to use halides, and among the halides, chlorides such as hydrochloride are particularly preferable. In addition, it is preferable that at least one of the metal compounds is a chloride, and it is more preferable that all of them are chlorides. It is thought that by using chlorides, the metal is complexed in a solution state, and the dispersion state of each metal on the supported carrier becomes uniform, and stable support is achieved. In addition, the growth of alloy particles due to other metal components such as ruthenium, tin, platinum, and iron in the obtained catalyst is suppressed, and the activity and selectivity are improved, while the stability of the catalyst during the reaction is improved.

More specifically, in the case of ruthenium, examples thereof include ruthenium chloride, ruthenium nitrate nitrosil, and tris(acetylacetonato)ruthenium. These ruthenium salts may be used alone, or two or more may be used in combination.

Specific examples of tin compounds include tin(II) chloride, tin(IV) chloride, tin(II) acetate, tin(IV) acetate, dibutyltin dilaurate, dibutyltin oxide, and dibutyltin dimethoxide. Tin compounds may be used singly or in combination of two or more.

In the case of platinum, a platinum precursor compound is used, and examples of the platinum precursor compound include platinum(IV) hexachloride (hexahydrate, etc.), potassium tetrachloroplatinate, potassium hexachloroplatinate, potassium tetracyanoplatonate, sodium hexachloroplatinate (hexahydrate), hydrogen hexahydroxyplatinate, potassium tetracyanoplatonate (II) (hydrate), tetrabutylammonium hexachloroplatinate, etc. The platinum precursor compound may be used alone or in combination of two or more.

As other metal compounds such as iron, specifically, iron salts, chromium compounds, and molybdenum compounds exemplified below can be used.

As the iron salt, it is preferable to use one selected from the group consisting of iron chloride, iron nitrate, iron sulfate and iron acetylacetonato.

As chromium compounds, various ones known to be used in the production of chromium oxide catalysts, such as inorganic acid salts such as chromium nitrate, chromium sulfate, and chromium chloride, organic acid salts such as chromium acetate, chromium oxalate, and chromium acetylacetonate, and inorganic acid salts such as chromium nitrate, chromium sulfate, and chromium chloride, can be used.

As the molybdenum compound, a molybdenum compound containing molybdenum element in an oxidation state is preferable, and examples thereof include molybdenum trioxide, molybdic acid, molybdate salt, and heteropolyacid. Among these, molybdenum trioxide and molybdate salt are more preferable. As the molybdate salt, examples thereof include ammonium paramolybdate, ammonium dimolybdate, and ammonium tetramolybdate. One type of molybdenum raw material may be used, or two or more types may be used in combination.

(menstruum)

When supporting the metal compound on the carrier, various solvents can be used to dissolve or disperse the metal compound, and can be used in various supporting methods. The type of solvent used at this time is not particularly limited as long as it can dissolve or disperse the metal compound, and does not adversely affect the subsequent calcination and hydrogen reduction of the metal support, and further the hydrogenation reaction using the present catalyst. Examples thereof include ketone solvents such as acetone, alcohol solvents such as methanol and ethanol, ether solvents such as tetrahydrofuran and ethylene glycol dimethyl ether, and water. These solvents can be used alone or as a mixed solvent. In the present invention, as described above, a halide is preferably used as the metal compound, and more preferably a chloride, but since the solubility of these halides is high, water is preferably used.

In addition, when dissolving or dispersing a metal compound, various additives may be added in addition to a solvent. For example, as described in Japanese Patent Application Laid-Open No. (Hei) 10-15388, by adding a carboxylic acid and/or carbonyl compound solution, when supported on a carrier, the dispersibility of each metal component on the carrier can be improved.

<Metal carrier>

The metal carrier containing the above metal component can be used after drying as needed, and it is preferable to use it after drying. If the metal carrier is not dried and subsequent reduction treatment is performed, the reaction activity may be lowered, and especially, when the dehalogen treatment described below is performed subsequently, it is preferable to dry it because it is possible to suppress the elution of the metal salt in the presence of an alkali usually used in the dehalogen treatment.

The drying method is not particularly limited as long as the solvent used during storage is removed. It is usually performed in the presence or circulation of an inert gas.

The drying pressure is not particularly limited, but is usually performed under atmospheric pressure or reduced pressure conditions.

The drying temperature is not particularly limited, but is usually 300°C or lower, preferably 250°C or lower, more preferably 200°C or lower, and usually 80°C or higher.

<Dehalogenation and cleaning>

The above metal support may be subjected to dehalogen treatment if necessary before the reduction process described below. In the metal support process described above, particularly when a halide such as chloride is used as a raw material for the metal component, halogen compounds may be generated within the reduction device during the reduction process described below. This is not a problem in laboratory-scale processing, but when performing industrial-scale reduction processing in large quantities, a large amount of halogen compounds may be generated within the reduction device, requiring exhaust gas treatment, and may also cause corrosion of the device. Therefore, it is preferable to perform dehalogen treatment before performing the reduction process.

The method for dehalogenation treatment is not particularly limited, but is usually performed by contacting the metal carrier with an alkaline compound in a gaseous or liquid phase, reacting the halogenide in the metal carrier, and then removing it by gaseous treatment or washing. Among these, it is preferable to treat it by contacting it with an alkaline compound in a liquid phase, and then removing it by washing, because of the ease of operation and the good efficiency of removing the halogenide from the metal carrier. Specifically, it is more preferable to contact it with an alkaline aqueous solution and then wash it with water.

The temperature of the dehalogen treatment is not particularly limited, but is usually 10°C or higher, preferably 20°C or higher, usually 150°C or lower, preferably 100°C or lower, and more preferably 80°C or lower. If it is higher than the lower limit, the dehalogen treatment can be performed efficiently, and if it is lower than the upper limit, volatilization, thermal decomposition, etc. of the solvent or the alkaline compound used for the treatment do not occur.

When an alkaline aqueous solution is used for dehalogenation treatment, the pH of the alkaline aqueous solution is not particularly limited, but is usually 7.5 or higher, preferably 8.0 or higher, and usually 13.0 or lower, preferably 12.5 or lower. When it is below the upper limit, there is no concern about the deterioration of the supported metal due to the pH being too high, and it is difficult for the supported metal to be eluted during the washing process described later. In addition, when it is above the lower limit, sufficient dehalogenation is performed.

As the type of alkaline compound, for example, alkali metal carbonates, bicarbonates, ammonia, ammonium carbonate, ammonium bicarbonate, etc. can be used. These can be used alone or in combination of two or more. Among them, weakly basic alkaline compounds are preferable. Using weakly basic alkaline compounds such as ammonia or ammonium salts tends to yield a catalyst with higher activity than using strongly basic alkaline compounds.

The amount of the alkaline compound is usually 0.1 to 50 equivalents, preferably 1 to 20 equivalents, and more preferably 1 to 10 equivalents, relative to the halogen ion contained in the carrier. The alkaline compound is usually used as an aqueous solution, and a water-soluble solvent such as methanol, ethanol, acetone, or further ethylene glycol dimethyl ether, or further a mixed solvent of these and water can be used. It is preferable to use the alkaline aqueous solution in an amount that completely fills the pores of the carrier supporting the metal component of the metal support, that is, more than the pore capacity of the carrier. The amount of the alkaline aqueous solution to be used is not particularly limited because it depends on the concentration of the alkaline aqueous solution, but is usually 0.8 to 20 times the pore capacity of the carrier of the metal support used, preferably 1 to 10 times, and more preferably 1 to 5 times.

It is preferable that the metal support treated with an alkaline compound be washed to remove excess alkaline compounds or generated halogenides. For washing, any solution that dissolves excess alkaline compounds or generated halogenides can be used, but water is preferred. In that case, the washing temperature is not particularly limited, and washing is usually performed at 10°C or higher and 100°C or lower, but since the washing efficiency in warm water is good, it is preferably 40°C or higher, more preferably 50°C or higher.

After the above alkali treatment or after the above washing, additional drying may be performed as needed. As drying conditions, the same conditions as for drying the metal support are used.

<Reduction treatment and reducing gas>

It is preferable that the above metal support be reduced by a reducing gas to form a metal-supported catalyst. The reducing gas in the present invention is not particularly limited as long as it has reducing properties, and examples thereof include hydrogen, methanol, hydrazine, etc., and is preferably hydrogen. That is, it is preferable that the metal-supported catalyst of the present invention is prepared through hydrogen reduction.

In addition, in the reduction treatment of the present invention, a reduction reaction occurs regardless of the type of reducing gas, resulting in a metal-supported catalyst. The amount of reducing gas required for the reduction treatment is expressed as the “hydrogen absorption amount.”

In the present invention, there is no particular limitation, but the reduction treatment of the metal support may be performed in one step or in multiple stages.

(Reduction treatment temperature)

When producing the metal-supported catalyst of the present invention, it is preferable to perform a reduction treatment by controlling the treatment temperature range.

The reduction treatment temperature is not particularly limited and may be a constant temperature or may be varied. It is usually 80°C or higher, preferably 100°C or higher, more preferably 150°C or higher, and usually 650°C or lower, preferably 600°C or lower, more preferably 580°C or lower. If it is below the upper limit temperature, there is no sintering of the metal component or adverse effects on the carrier, while if it is above the lower limit temperature, the reduction reaction proceeds sufficiently.

Specifically, the reduction treatment can be carried out while maintaining a specific temperature within a desired temperature range for a certain period of time, or can be carried out while increasing the temperature within the desired temperature range for a certain period of time. From the viewpoint of improving the efficiency of the reaction time, it is preferable to carry out the reduction treatment while increasing the temperature for a certain period of time, because the metal support is accompanied by heat generation due to the reduction treatment, and the temperature of the reaction system rises. On the other hand, in the case where severe heat generation is involved, a method of maintaining the temperature at a certain level is preferable so that the reaction can be controlled accurately.

(reducing gas concentration)

The concentration of the reducing gas during the reduction treatment of the present catalyst is not particularly limited, but may be 100% by volume of the reducing gas, or may be diluted with an inert gas. The inert gas referred to here is a gas that does not react with the metal support or the reducing gas, and examples thereof include nitrogen, water vapor, etc., and nitrogen is usually used. The concentration of the reducing gas when diluted with an inert gas is usually 5% by volume or more, preferably 15% by volume or more, more preferably 30% by volume or more, and even more preferably 50% by volume or more, with respect to the total gas components. In addition, a low-concentration reducing gas may be used at the beginning of the reduction, and then the concentration of the reducing gas may be gradually increased to perform the reduction treatment.

(flux)

In order to determine the flow rate of the reducing gas, it is desirable to know the amount of hydrogen absorbed by the catalyst during reduction in advance. The method for measuring the amount of hydrogen absorbed is not particularly limited, but it is usually desirable to perform the reduction by adjusting the amount of hydrogen supplied per unit time and also adjusting the temperature increase time per unit time, that is, the Temperature Programmed Reduction method (hereinafter referred to as the TPR method). By using this method, the amount of hydrogen absorbed and the absorption temperature of the catalyst can be precisely measured.

The TPR method places a target catalyst in a container, increases the temperature of the container while flowing a constant flow of hydrogen, and continuously measures the amount of hydrogen at the inlet and outlet of the container. By this method, the amount of hydrogen absorbed during reduction of a metal-supported catalyst can be determined. Specifically, it can be measured by the method described in the examples.

During the reduction treatment of the present catalyst, the reducing gas can be used in a sealed reactor or circulated through the reactor, but it is preferable to circulate through the reactor. Water or ammonium chloride, etc. are produced as by-products in the reactor due to the reduction treatment, and these by-products may have adverse effects on the metal support before the reduction treatment, the metal support subjected to the reduction treatment, and the obtained catalyst, but this can be prevented. In other words, by circulating the reducing gas, the by-products can be discharged outside the reaction system.

The amount of reducing gas required for the reduction treatment is not particularly limited as long as the purpose of the present invention is achieved, and can be appropriately set depending on the reducing device, the size of the reactor during reduction, and the flow conditions. Usually, with respect to the hydrogen absorption amount obtained by the above TPR method, the flow rate is 1.5 times or more, preferably 2 times or more, more preferably 3 times or more, and most preferably 5 times or more, the amount of hydrogen required for each reduction treatment under the condition that the contact efficiency of hydrogen flowing through the catalyst layer is high. If it is equal to or greater than the lower limit, reduction is sufficiently performed, particularly when the contact efficiency with hydrogen is sufficient. The upper limit is not particularly limited, but from the viewpoints of no problem in treating exhaust gas, no flying of the metal support or the manufactured catalyst due to the reducing gas, and furthermore, avoiding waste of excess reducing gas, it is usually 500 times or less, and preferably 200 times or less.

(Reduction processing time)

The time required for reduction treatment varies depending on the amount of metal support to be treated, the device used, etc., but is usually 7 minutes or longer, preferably 15 minutes or longer, more preferably 30 minutes or longer, even more preferably 1 hour or longer, and most preferably 2 hours or longer, and is usually 40 hours or shorter, preferably 30 hours or shorter.

The degree of reduction of the above metal support can be judged by the halogen concentration in the oxidation-stabilized metal support catalyst after the reduction treatment described below. The halogen concentration in the metal support catalyst is not particularly limited, but is usually 0.8 mass% or less, more preferably 0.7 mass% or less, and even more preferably 0.5 mass% or less. The lower halogen concentration is preferable because the elution of halogen into the reaction solution is suppressed during the reduction reaction using the present catalyst. The lower limit of the halogen concentration is not particularly limited, but is usually 0.005 mass% or more, and preferably 0.01 mass% or more. When the halogen concentration is within the above range, the reduction treatment of the metal support is sufficiently performed, the elution of halogen into the reaction solution is suppressed to a low level, and at the same time, the activity of the reduction reaction using the present catalyst is improved, while the reaction selectivity is also improved, and the stability of the catalyst is further improved.

<The Sun of Desirable Manufacturing Method>

The method for producing the catalyst of the present invention comprises, as described above, a metal supporting process, a dehalogenation process, a washing process, and a reduction process. However, as a preferred embodiment of the manufacturing method, in the reduction process, there is a method of passing a reducing gas through a catalyst in a fixed bed, a method of circulating a reducing gas through a catalyst which is stationary on a tray or belt, and a method of circulating a reducing gas through a fluidized catalyst. Of these, it is preferred to perform the reduction treatment while fluidizing the metal supporting material in the reduction treatment. By performing the reduction treatment while fluidizing, the surface area of contact between the metal supporting material and the reducing gas during the reduction treatment increases, so the efficiency of the reduction treatment is improved.

There is no particular limitation on the method of specifically fluidizing, and it is sufficient that the metal carrier, etc., which is subjected to reduction treatment, is accompanied by a movement that increases the surface area of contact with the reducing gas. For example, there is a method of rotating a reactor containing the metal carrier, etc., which is subjected to reduction treatment, or a method of incorporating a device configuration in which the metal carrier, etc. in the reactor is stirred or moves up and down.

As a specific fluidization method, a method of processing using various kilns (heating furnaces) can be mentioned.

Specifically, preferred manufacturing methods include, for example, methods using a continuous kiln or a batch kiln.

(Continuous kiln)

A continuous kiln refers to one that can continuously supply a metal support to perform reduction and continuously discharge the reduced catalyst. Specifically, there are continuous rotary kilns, roller hearth kilns, belt kilns, tunnel kilns, etc., and among them, in the manufacturing method of the present invention, a continuous rotary kiln is preferable because the fluidity of the metal support is high and the contact efficiency with the reducing gas is high.

There are no particular limitations on the operating conditions of the continuous kiln as long as the conditions for the reduction treatment mentioned above are satisfied, and they can be set appropriately depending on the device used. Normally, in a continuous kiln, it can be operated so as to satisfy the conditions for the reduction treatment mentioned above by controlling the flow rate or temperature of the reducing gas.

Since a continuous kiln can continuously supply a metal carrier or a reducing gas, the method of supplying the metal carrier into the continuous kiln or the flow rate of the reducing gas can be controlled.

The flow rate of the reducing gas in the continuous kiln is not particularly limited, but when the amount of hydrogen required for reduction calculated by the TPR measurement of the metal support is called the "hydrogen absorption amount A (m ³ /kg)" and the amount of the metal support fed into the continuous kiln is called B (kg / h), the hydrogen flow rate is usually (1.5 × A × B) m ³ /h or more, preferably (2 × A × B) m ³ /h or more, more preferably (5 × A × B) m ³ /h or more. When the hydrogen flow rate is equal to or greater than the lower limit above, a sufficient amount of hydrogen absorbed by the catalyst is secured, and the performance of the resulting catalyst is maintained at a high level. The upper limit is not particularly limited, but is (1000 × A × B) m ³ /h or less, preferably (500 × A × B) m ³ /h or less, more preferably (300 × A × B) m ³ /h or less in order to reduce the amount of hydrogen wasted.

The flow direction of the metal carrier undergoing reduction treatment in a continuous kiln and the flow direction of the reducing gas such as hydrogen can be appropriately adjusted depending on the situation of the reduction treatment, and the flow direction of the reducing gas can be either parallel or countercurrent to the flow direction of the metal carrier. In particular, it is preferable that the flow direction of hydrogen is countercurrent to the flow direction of the metal carrier (in opposite directions) from the viewpoint that the catalyst reaching the outlet of the continuous kiln can come into contact with high-purity hydrogen.

The rotation speed of the continuous rotary kiln is not particularly limited. If the rotation speed is fast, the contact efficiency between the metal support and hydrogen becomes good, but since wear of the catalyst occurs, it is usually 0.5 rpm or more and 10 rpm or less, and preferably 5 rpm or less.

(batch kiln)

A batch kiln is one in which a predetermined amount of a metal carrier is placed in advance in the kiln, and the temperature is sequentially raised to the target reduction temperature under the flow of a reducing gas to perform reduction at the predetermined temperature. Specific examples thereof include a fixed-bed heating furnace in which a metal carrier is charged and processed, a shelf-type heating furnace in which the metal carrier is placed on a shelf and heated, a shuttle kiln in which a calcination cart enters and exits an electric furnace, and a batch-type rotary kiln.

Considering the efficiency of contact between the metal support and the reducing gas, a stationary heating furnace, a batch-type rotary kiln, which charges and processes the metal support, is preferable, and it is preferable to perform the process using a batch-type rotary kiln having a device that circulates the catalyst while uniformly reducing it.

While continuous kilns are usually operated at a constant flow rate when introducing reducing gas due to limitations in the equipment, batch kilns have a reaction tank for each batch, so the temperature raising method, flow rate of reducing gas, concentration, etc. can be changed for each batch.

(Operating conditions of batch kiln)

There are no special restrictions on the operating conditions of the batch kiln and they can be set appropriately depending on the configuration of the device, etc.

The batch-type rotary kiln, which is very suitably used in the present invention, starts heating after a predetermined amount of metal support is injected in advance, so it is possible to control the heating time to the final reduction temperature in more detail than the continuous rotary kiln.

The time for the reduction treatment is not particularly limited, but is usually 1 hour or longer, preferably 2 hours or longer, and usually 40 hours or shorter, preferably 30 hours or shorter, and more preferably 10 hours or shorter. If it is too short than the lower limit, when rapid hydrogen absorption occurs, a large amount of metal support is reduced at once, so that a large amount of hydrogen absorption occurs along with severe heat generation, and sintering of the catalyst progresses, and stable operation may become difficult. In addition, if it is longer than the lower limit, the reduction time is secured, reduction is sufficient, and sufficient reaction activity and selectivity as a catalyst are obtained.

Meanwhile, if the reduction treatment time is below the upper limit, the productivity of the catalyst can be secured and there is no loss of hydrogen, which is industrially advantageous.

When a batch-type rotary kiln is used, the concentration and flow rate of the reducing gas can be appropriately changed for each batch according to the reduction treatment situation.

The preferred concentration of reducing gas in the operation of a batch rotary kiln is as described above.

The flow rate of the reducing gas is not particularly limited and can be appropriately set depending on the situation of the reduction reaction. The amount of hydrogen required until the end of reduction is calculated by TPR analysis of the unreduced catalyst, and is usually used at least 5 times, preferably at least 10 times, and more preferably at least 20 times the required amount of hydrogen. In addition, it is usually 5000 times or less, and preferably 1000 times or less. If it is more than the lower limit, hydrogen deficiency does not occur, and if it is less than the upper limit, unnecessary reducing gas is not consumed, which is economically advantageous.

The rotation speed of the batch rotary kiln is not particularly limited, but if it is fast, the contact efficiency with hydrogen is good, but wear of the catalyst occurs, so it is usually performed at 0.5 to 10 rpm, preferably 0.5 to 5 rpm.

(Oxidation stabilization of catalyst)

In the production of the metal-supported catalyst of the present invention, the oxidation state of the metal-supported catalyst obtained by reducing the metal-supported substance is usually controlled. Particularly, when producing a large amount of the catalyst, it is preferable to perform oxidation stabilization of the catalyst. The metal-supported catalyst obtained by reduction is in a state in which the metal component is reduced and highly dispersed. By performing oxidation stabilization, the possibility of metal sintering occurring due to rapid heat generation is reduced compared to taking it out into the air as it is, and the possibility of ignition (self-ignition in the case of a flammable carrier, and ignition of surrounding combustibles) can also be reduced, which is preferable. By stabilizing under controlled conditions, high dispersion is maintained, and high activity can be exhibited in the subsequent hydrogenation reaction.

The method for the above oxidation stabilization is not particularly limited, but includes a method of adding water to a catalyst or a method of putting a catalyst into water, a method of stabilizing oxidation with a gas having a low oxygen concentration diluted with an inert gas under flow, a method of stabilizing with carbon dioxide, etc. Among these, a method of adding water to a catalyst or a method of putting a catalyst into water, a method of stabilizing oxidation with a gas having a low oxygen concentration are preferable, and a method of stabilizing oxidation with a gas having a low oxygen concentration (hereinafter referred to as a “slow oxidation method”) is more preferable, and stabilizing oxidation with a gas having a low oxygen concentration under flow is particularly preferable.

The oxygen concentration when stabilizing oxidation with a gas having a low oxygen concentration is not particularly limited, but is usually 0.2 vol% or more, preferably 0.5 vol% or more as the oxygen concentration at the start of slow oxidation, and on the other hand, 10 vol% or less, preferably 8 vol% or less, and more preferably 7 vol% or less. If it is equal to or greater than the lower limit, the time required for complete oxidation stabilization can be shortened, and stabilization becomes sufficient. On the other hand, if it is equal to or less than the upper limit, there is no concern about deactivation because the catalyst does not reach a high temperature. In addition, in order to create a gas having a low oxygen concentration, it is preferable to dilute air with an inert gas, and nitrogen is preferable as the inert gas.

The oxygen concentration during slow oxidation can be maintained at the oxygen concentration at the start of slow oxidation, but if the temperature inside the catalyst becomes high and the catalyst does not deteriorate, the oxygen concentration can be gradually increased after starting slow oxidation.

When the slow oxidation stability is achieved at low oxygen concentration, it is preferable to control the temperature of the catalyst so that it does not exceed 130°C. When the temperature of the catalyst is 130°C or lower, rapid oxidation does not occur, so that sintering of the catalyst does not occur and the strength of the carrier is maintained without deterioration. From the above viewpoint, it is preferable to control the oxygen concentration and flow rate so that the temperature of the catalyst more preferably does not exceed 120°C, and even more preferably does not exceed 110°C.

Methods for stabilizing oxidation with a gas having a low oxygen concentration include a method of passing a gas having a low oxygen concentration through a catalyst in a fixed bed, a method of circulating a gas having a low oxygen concentration through a catalyst that is stationary on a tray or belt, and a method of circulating a gas having a low oxygen concentration through a fluidized catalyst.

The better the dispersion of the supported metal on the metal-supported catalyst, the more rapidly the oxidation stabilization progresses, and also, since a large amount of oxygen reacts, among the above methods, a method of passing a gas with a low oxygen concentration through the catalyst in a fixed bed and a method of circulating a gas with a low oxygen concentration through a fluidized catalyst are preferable, and a method of circulating a gas with a low oxygen concentration through a fluidized catalyst is particularly preferable.

(Method of preserving catalyst)

When preserving the metal-supported catalyst of the present invention, it is preferable to preserve it in an atmosphere having an oxygen concentration of 15 vol% or less. By preserving it in such an atmosphere, if oxidation progresses slowly even after oxidation stabilization, oxidation can proceed slowly in a sealed container. The lower limit of the oxygen concentration is not particularly limited, but it is usually preferable to be 0.2 vol% or more in order to proceed with oxidation.

In addition, since gas-stabilized catalysts are highly hygroscopic, which poses a major problem in non-aqueous reactions, it is desirable to store them in sealed containers.

<Usage>

The catalyst of the present invention is very suitable as a catalyst for a reduction reaction, and is very suitable for use, for example, in the hydrogenation of a carboxylic acid and/or a carboxylic acid ester. That is, it is very suitable for use in a method for producing an alcohol, in which a carboxylic acid and/or a carboxylic acid ester is reduced by contacting the metal-supported catalyst of the present invention with the carboxylic acid and/or the carboxylic acid ester, thereby obtaining an alcohol corresponding to each of the carboxylic acid and/or the carboxylic acid ester. Any carboxylic acid or carboxylic acid ester that is the target of the reduction reaction can be used as an industrially readily available catalyst.

Examples of the carboxylic acid and/or carboxylic acid ester that can be provided for the reduction reaction using the catalyst of the present invention include aliphatic chain carboxylic acids such as acetic acid, butyric acid, lauric acid, oleic acid, linoleic acid, linolenic acid, stearic acid, and palmitic acid; aliphatic cyclic carboxylic acids such as cyclohexanecarboxylic acid, naphthenic acid, and cyclopentanecarboxylic acid; aliphatic polycarboxylic acids such as oxalic acid, malonic acid, succinic acid, methylsuccinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, sebacic acid, cyclohexanedicarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,3,4-cyclohexanetricarboxylic acid, bicyclohexyldicarboxylic acid, and decahydronaphthalenedicarboxylic acid; Examples include aromatic carboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, and trimesic acid.

The carboxylic acid is not particularly limited, but is preferably a chain or cyclic saturated aliphatic carboxylic acid, more preferably a carboxylic acid having 20 or fewer carbon atoms and not containing a functional group other than a carboxyl group, and even more preferably a dicarboxylic acid having 20 or fewer carbon atoms and not containing a functional group other than a carboxyl group and represented by formula (2).

HOOC-R ¹ -COOH (2)

(In the formula, R ¹ may have a substituent, and is an aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms other than the substituent.)

Particularly preferably, an aliphatic or alicyclic polycarboxylic acid or an ester thereof having 4 to 14 carbon atoms is highly suitable because it has high activity in the reduction reaction and high selectivity.

In the present invention, it is particularly preferable to use 1,4-cyclohexanedicarboxylic acid or an ester thereof as a reactant to produce a corresponding alcohol by a reduction reaction. That is, a method for producing alcohol is preferable in which 1,4-cyclohexanedicarboxylic acid or an ester (diester) of 1,4-cyclohexanedicarboxylic acid is used as a raw material and the catalyst of the present invention is brought into contact with it to perform reduction.

In addition, when using esters of these carboxylic acids, lower alcohols such as methanol, ethanol, i-propanol, and n-butanol can be used as alcohol components.

It can also be esterified with the same alcohol as the alcohol obtained by reduction. In this case, there is an advantage in that the separation of the alcohol produced in the subsequent hydrogenation reaction becomes unnecessary.

The reduction reaction using the catalyst of the present invention may be performed without a solvent or in the presence of a solvent, but is usually performed in the presence of a solvent.

As a solvent, solvents such as water, lower alcohols such as methanol or ethanol, alcohols of reaction products, ethers such as tetrahydrofuran, dioxane, and ethylene glycol dimethyl ether, and hydrocarbons such as hexane and decalin can be used. These solvents can be used alone or as a mixture of two or more types.

Especially when reducing carboxylic acids, it is preferable to use a solvent containing water for reasons such as solubility.

The amount of solvent to be used is not particularly limited, but is usually about 0.1 to 20 mass times that of the raw material carboxylic acid or carboxylic acid ester, preferably about 0.5 to 10 mass times that of the raw material, and more preferably about 1 to 10 mass times that of the raw material.

The reduction reaction using the catalyst of the present invention is usually carried out under hydrogen gas pressure. The reaction is usually carried out at 100 to 300°C, but is preferably carried out at 150 to 300°C. The reaction pressure is 1 to 30 MPa, but is preferably 1 to 25 MPa, and more preferably 5 to 25 MPa.

The reduction reaction using the catalyst of the present invention can be carried out in both a liquid phase and a gas phase, but since vaporizing the carboxylic acid/carboxylic acid ester and carrying out the reduction reaction while maintaining the gaseous state requires a large facility and also requires a large amount of energy, it is preferable to carry it out in a liquid phase.

Additionally, a method for hydrogenating a carboxylic acid and/or a carboxylic acid ester by contacting the catalyst of the present invention with the carboxylic acid and/or carboxylic acid ester is also included in the scope of the present invention.

Example

The present invention is described more specifically by way of examples below, but the present invention is not limited to the following examples unless the gist of the present invention is exceeded.

<TPR measurement method>

0.1 g of the catalyst was placed in a thin quartz tube, and 10% H ₂ /He was flowed at 20 ml/min and maintained until hydrogen substitution within the system was completed and the H ₂ concentration became stable. After that, the temperature was increased at a constant rate to 700°C for 60 minutes. During this time, the amount of outlet hydrogen was continuously measured with a mass spectrometer, and the amount of absorbed hydrogen was calculated.

<Method for checking the reaction activity of a catalyst>

The reaction activity and selectivity of the catalyst obtained in the present invention were confirmed using the production reaction of 1,4-cyclohexanedimethanol (CHDM) by the hydrogenation reaction of 1,4-cyclohexanedicarboxylic acid (CHDA).

Into a 200 mL induction stirring autoclave (hereinafter sometimes referred to as a "reactor") containing Hastelloy C (registered trademark), 40 g of water, 10 g of CHDA (a mixture of cis-isomer and trans-isomer: manufactured by Tokyo Chemical Industry Co., Ltd.), and 2 g of the catalyst to be evaluated were placed, and after the inside of the reactor was replaced with hydrogen, the hydrogen partial pressure was set to 1 MPa, and under stirring at 1000 rpm (a stirring number that is not too slow to achieve the hydrogen supply rate and not too high to cause catalyst cracking), the reactor was heated, and the reaction was started at 240°C with a reaction pressure of 8.5 MPa at a predetermined temperature. Hydrogen was continuously supplied into the reactor from a hydrogen accumulator, and the reaction was performed at a constant 240°C and 8.5 MPa for 3 hours. After completion of the reaction, the presence or absence of cracking in the catalyst was visually confirmed. At this time, reactions in which catalyst cracking occurred were excluded because the apparent reaction rate was high and the selectivity could not be accurately compared.

The obtained reaction solution was neutralized and titrated with NaOH to obtain the conversion of carboxyl groups, and the product was analyzed using gas chromatography. The main product was the target product, CHDM, and the main by-products were two types: cyclohexanemethanol (CHM) and 4-methylcyclohexanemethanol (MCHM). Since almost all of the by-products except for the above two types were CHDM, the catalytic performance was compared by the conversion of carboxyl groups and the yield of by-products.

(Comparative Example 1)

A catalyst was prepared by a method according to Example 4 of Japanese Patent Application Laid-Open No. 2001-9277, using a cylindrical activated carbon having a diameter of 1 mm and a length of 2 to 5 mm (R1 EXTRA manufactured by Cabot Norit) as a carrier. Specifically, ruthenium chloride hydrate (RuCl ₃ ·xH ₂ O), platinum (IV) hexachloride (hexahydrate, etc.) (H ₂ PtCl ₆ ·6H ₂ O), and tin (II) chloride (SnCl ₂ ·2H ₂ O) were dissolved in a diluted hydrochloric acid solution, and activated carbon treated with nitric acid was added thereto. The solvent was removed and dried, and the dried catalyst was treated by adding it to an ammonium bicarbonate solution, followed by filtration, washing, and drying to prepare a metal support. Among the methods for preparing a metal support, the dissolved water of the metal chloride was 1.1 ml of 0.3% diluted hydrochloric acid per 1 g of activated carbon used. The amount of the metal chloride introduced was such that when the entire amount introduced was supported and reduced by hydrogen and oxidized and stabilized, the metal contents in the supported catalyst were 5.5 mass% of Ru, 2.4 mass% of Pt, and 6.4 mass% of Sn (hereinafter, the supported amounts of the metals are all expressed in mass%). In addition, the ammonium bicarbonate used was used as an 11 mass% aqueous solution in an amount 1.7 times the molar amount of chlorine of the metal chloride, and water at 90°C was used for washing.

The obtained metal support was reduced at 500°C in a hydrogen stream, and then oxidized and stabilized in a diluted oxygen atmosphere to produce a catalyst. Hereinafter referred to as “reduction catalyst.”

The reaction was carried out with this catalyst. The conversion rate and yield of by-products are shown in Table 1.

Additionally, the metal type column in Table 1 indicates the compounds used for metal types other than ruthenium, platinum, and tin.

(Comparative Example 2)

The reduction catalyst obtained in Comparative Example 1 was supported with Fe(III) acetylacetonate (Fe(acac) ₃ ), and the catalyst was prepared so that the Fe loading amount after reduction was 0.1 mass%. Specifically, a predetermined amount of Fe(acac) ₃ was dissolved using 0.86 ml of tetrahydrofuran solvent per 1 g of the reduction catalyst, about 10 g of the reduction catalyst obtained in Comparative Example 1 was added, stirred, and left for 1 hour. Thereafter, the mixture was evaporated at 80°C for 1 hour under a reduced pressure of 1 kPa, placed in a glass tube, set in an electric furnace, and dried at 150°C for 2 hours under a circulation of 5 L/hour of argon.

2.5 g of the dried catalyst was put into the glass tube again, set in an electric furnace, and reduced at 500°C for 2 hours under a flow of 5 L/hour of hydrogen. Thereafter, the mixture was cooled under a flow of argon, and stabilized under a flow of 6 vol% oxygen/nitrogen at room temperature, thereby obtaining a 0.1% Fe-supported catalyst.

Using this catalyst (the amount of catalyst used was such that the amount of reduction catalyst used in the preparation was 2 g), the same reaction as in Comparative Example 1 was performed. The results are shown in Table 1.

(Comparative Example 3)

In Comparative Example 2, iron (III) chloride hexahydrate (FeCl ₃ ·6H ₂ O) was used instead of Fe (III) acetylacetonate (Fe (acac) ₃ ) and water was used as a solvent, but the same method as Example 1 was used to obtain an Fe-supported catalyst so that the Fe metal content was 0.2 mass%. Using this catalyst, the same reaction as in Comparative Example 1 was performed. The results are shown in Table 1.

(Comparative Example 4)

In Comparative Example 2, a 0.5% Fe-supported catalyst was obtained in the same manner as in Comparative Example 2, except that Fe(acac) ₃ was used so that 0.5 mass% of Fe metal was used. The same reaction as in Comparative Example 1 was performed using this catalyst. The results are shown in Table 1.

(Comparative Example 5)

In Comparative Example 3, a 0.5% Fe-supported catalyst was obtained in the same manner as in Comparative Example 3, except that FeCl ₃ ·6H ₂ O was used so that 0.5 mass% of Fe metal was used. The same reaction as in Comparative Example 1 was performed using this catalyst. The results are shown in Table 1.

(Reference Example 1)

In Comparative Example 3, a 0.2 mass% Cr-supported catalyst was _{obtained in the same manner as in Comparative Example 3, except that chromium (III) chloride hexahydrate (CrCl 3 6H 2} O) was used instead of iron (III) chloride hexahydrate (FeCl 3 6H ₂ O). Using this catalyst, the same reaction as in Comparative Example 1 was performed. The results are shown in Table 1.

(Reference Example 2)

In Comparative Example 2, a 0.5% Cr-supported catalyst was obtained in the same manner _as in Comparative Example 2, except that Cr(III) acetylacetonato (Cr(acac) ₃ ) was used instead of Fe(III) acetylacetonato (Fe(acac)3). The same reaction as in Comparative Example 1 was performed using this catalyst. The results are shown in Table 1.

(Comparative Example 6)

In Comparative Example 2, ammonium paramolybdate (ammonium molybdate (VI) tetrahydrate ((NH ₄ ) ₆ Mo ₇ O ₂₄ 4H ₂ O)) was used instead of Fe (III) acetylacetonato (Fe (acac) ₃ ) and water was used as a solvent, but a 0.5% Mo-supported catalyst was obtained in the same manner as Comparative Example 2. Using this catalyst, the same reaction as in Comparative Example 1 was performed. The results are shown in Table 1.

(Comparative Example 7)

RuCl ₃ · xH ₂ O (Ru content 41.9%) 1.131 g, H ₂ PtCl ₆ · 6H ₂ O 0.547 g, SnCl ₂ · 2H ₂ O 0.883 g, and FeCl ₃ · 6H ₂ O 1.196 g were dissolved in a 0.3% hydrochloric acid solution. 7.41 g of activated carbon that had been treated with the same nitric acid as in Comparative Example 1 was added to this solution, stirred sufficiently, and left for 3 hours. After 3 hours, it was dried using an evaporator, then transferred to a calcination tube, and dried at 150°C for 2 hours under argon gas flow. The catalyst was added to an 11 mass% aqueous solution of ammonium bicarbonate corresponding to 1.7 equivalents of the total chlorine amount of the metal chloride used, treated for 1 hour, filtered, washed with water at 90°C, and dried using an evaporator. The dried catalyst was transferred to a calcination tube and further dried at 150°C under argon gas flow. 2.5 g of the further dried catalyst was reduced at 500°C under hydrogen flow, and after cooling, stabilized with 6% oxygen/nitrogen to prepare a 5.5% Ru-2.4% Pt-5.4% Sn-0.47% Fe/activated carbon (calculated value based on the input base) catalyst supported in a four-component batch (referred to as “FeCl ₃ batch” in Table 1). The same reaction as in Comparative Example 1 was performed using 2 g of this catalyst. The results are shown in Table 1.

(Example 1)

A 0.2% Fe-0.2% Cr supported catalyst was obtained in the same manner as Comparative Example 2, except that FeCl ₃ ·6H ₂ O and CrCl ₃ ·6H ₂ O were used so that the Fe metal content and Cr metal content were 0.2% and 0.2%, respectively, in the reduction catalyst obtained in Comparative Example 1, and that water was used as a solvent. Using this catalyst, the same reaction as in Comparative Example 1 was performed. The results are shown in Table 1.

(Example 2)

A 0.4% Fe-0.1% Cr supported catalyst was obtained in the same manner as Comparative Example 2, except that FeCl ₃ ·6H ₂ O and CrCl ₃ ·6H ₂ O were used so that the Fe metal content was 0.4% and the Cr metal content was 0.1% in the reduction catalyst obtained in Comparative Example 1, and that water was used as a solvent. The same reaction as in Comparative Example 1 was performed using this catalyst. The results are shown in Table 1.

(Example 3)

A 0.2% Fe-0.2% Mo supported catalyst was obtained in the same manner as Comparative Example 2, except that FeCl ₃ ·6H ₂ O, (NH ₄ ) ₆ Mo ₇ O ₂₄ ·4H ₂ O were used so that the Fe metal content and Mo metal content were 0.2% and that water was used as a solvent, respectively, in the reduction catalyst obtained in Comparative Example 1. The catalyst was used to carry out the same reaction as in Comparative Example 1. The results are shown in Table 1.

(Example 4)

A 0.4% Fe-0.1% Mo supported catalyst was obtained in the same manner as Comparative Example 2, except that FeCl ₃ ·6H ₂ O and ammonium molybdate (VI) tetrahydrate ((NH ₄ ) ₆ Mo ₇ O ₂₄ ·4H ₂ O) were used so that the Fe metal content was 0.4% and the Mo metal content was 0.1% in the reduction catalyst obtained in Comparative Example 1, and that a 3% HCl aqueous solution was used as a solvent. The same reaction as in Comparative Example 1 was performed using this catalyst. The results are shown in Table 1.

Metal type Addition amount
(wt%) Call rate
(%) CHM
(%) MCHM
(%) Total of byproducts
(%) Total of by-products/uncounted
(%) Comparative Example 1 Unmodified - 99.3 0.38 1.09 1.47 - Comparative Example 2 Fe(acac) ₃ 0.1 99.2 0.29 0.79 1.08 73.6 Comparative Example 3 FeCl ₃ 0.2 99.3 0.30 0.82 1.12 76.2 Comparative Example 4 Fe(acac) ₃ 0.5 98.9 0.28 0.61 0.89 60.3 Comparative Example 5 FeCl ₃ 0.5 99.1 0.28 0.63 0.91 62.2 Reference Example 1 CrCl ₃ 0.2 99.2 0.24 0.87 1.10 75.1 Reference example 2 Cr(acac) ₃ 0.5 97.9 0.27 1.05 1.32 89.5 Comparative Example 6 (NH ₄ ) ₆ Mo ₇ O ₂₄ 0.5 99.3 0.32 1.00 1.32 89.6 Comparative Example 7 FeCl ₃ batch 0.5 99.2 0.52 0.39 0.91 61.7 Example 1 FeCl ₃ 0.2 99.0 0.12 0.27 0.39 26.5 CrCl ₃ 0.2 Example 2 FeCl ₃ 0.4 99.2 0.22 0.52 0.75 50.9 CrCl ₃ 0.1 Example 3 FeCl ₃ 0.2 99.2 0.29 0.28 0.57 38.8 (NH ₄ ) ₆ Mo ₇ O ₂₄ 0.2 Example 4 FeCl ₃ 0.4 99.2 0.23 0.53 0.75 51.2 (NH ₄ ) ₆ Mo ₇ O ₂₄ 0.1

As is clear from Table 1, the catalyst of the present invention supporting Fe and Cr and the catalyst of the present invention supporting Fe and Mo can lower the yield of the main by-products, cyclohexanemethanol (CHM) and 4-methylcyclohexanemethanol (MCHM), while maintaining a high conversion rate. In contrast, Comparative Examples 2 to 5 supporting only iron and Comparative Example 6 supporting only molybdenum show a certain degree of effect when compared with an unmodified catalyst that is not modified with iron, etc., but it can be seen that they are inferior to the catalyst of the present invention.

As described above, it can be seen that the catalyst of the present invention exhibits excellent effects, as the high conversion rate is maintained and the by-product yield is suppressed to 60% or less compared to that without addition.

Industrial applicability

According to the present invention, by adding a combination of new specific metals to a conventional reduction catalyst, the by-product yield is extremely reduced and the target product yield is improved. Since the by-product yield is extremely reduced, when used as a polymer raw material thereafter, it becomes possible to omit or simplify a precise purification process, and therefore the present invention is an extremely useful technology industrially.

Claims (8)

A metal-supported catalyst for the hydrogenation of a carboxylic acid and/or a carboxylic acid ester, wherein ruthenium, tin and platinum are supported on a support, wherein the metal-supported catalyst is further supported with iron, and chromium and/or molybdenum. In the first paragraph,
A metal-supported catalyst, wherein the amount of iron supported is 0.01 mass% or more and 4 mass% or less with respect to the total mass of the metal-supported catalyst, and further, the total amount of chromium and/or molybdenum supported is 0.01 mass% or more and 2 mass% or less. In paragraph 1 or 2,
A metal-supported catalyst, wherein the carrier is a carbonaceous carrier. In paragraph 1 or 2,
A metal-supported catalyst, wherein the total supported amount of ruthenium, tin, platinum, iron, molybdenum, and chromium is 5 mass% or more based on the total mass of the metal-supported catalyst. In paragraph 1 or 2,
A metal-supported catalyst prepared by subjecting the metal-supported catalyst to hydrogen reduction. A method for producing alcohol, comprising contacting a carboxylic acid and/or a carboxylic acid ester with the metal-supported catalyst described in claim 1 or 2 to perform reduction, thereby obtaining an alcohol corresponding to each of the carboxylic acid and/or the carboxylic acid ester. A method for hydrogenating a carboxylic acid and/or a carboxylic acid ester, comprising contacting the carboxylic acid and/or the carboxylic acid ester with a metal-supported catalyst as described in claim 1 or 2. In Article 6,
A method for producing alcohol, wherein the carboxylic acid is 1,4-cyclohexanedicarboxylic acid and the carboxylic acid ester is an ester of 1,4-cyclohexanedicarboxylic acid.