Gold-supported catalyst and method for producing the same, and method for producing anilines and hydrogen gas using the gold-supported catalyst

Abstract

In methods for producing anilines by reducing aromatic nitro compounds, which are unreducible substances, H2 and petroleum-derived alcohols were used as reducing agents, but there were issues from the perspective of safety and environmental impact. [Solution] The present invention provides a method for reducing aromatic nitro compounds, which is characterized by high safety and low environmental impact because it uses polysaccharides such as cellulose or polyols and an aqueous solvent in the presence of a gold-supported catalyst obtained by immobilizing gold nanoparticles on the surface of an inorganic crystalline support.

Description

[Technical Field]

[0001] The present invention relates to a gold-supported catalyst used for reducing a reducible substance using polysaccharides or polyols as a hydrogenation source, a method for producing the catalyst, a method for producing anilines using the catalyst, and a gold-supported catalyst used for generating hydrogen gas by dehydrogenating polysaccharides or polyols in a solvent, a method for producing the catalyst, and a method for producing hydrogen gas using the catalyst. [Background technology]

[0002] Chemical reactions utilizing molecular hydrogen (H2) are widely used in applications such as hydrogenation of organic matter, hydrogenation of oils and fats, hydrogen peroxide synthesis, oxygen scavenging, and reduction of metal species. However, H2 is a flammable gas with a wide explosive range, and its small molecular size can lead to gas leaks and metal embrittlement, posing safety challenges. To address these issues, reactions using hydrogen sources other than H2 are one possible solution.

[0003] Reactions that extract hydrogen from compounds other than H2 and utilize it as a hydrogenation source are called hydrogen transfer reactions. Traditionally, these hydrogen transfer reactions have been carried out using primary or secondary alcohols as hydrogen sources, but there have been challenges such as the high environmental impact due to the petroleum-derived components and the need for safety measures because they are volatile organic substances.

[0004] Non-patent documents 1-3 describe methods for reducing aromatic nitro compounds to anilines without using H2, but these reports utilize alcohols and organic solvents, which are petroleum-derived components with high environmental impact. Furthermore, the use of volatile organic substances as reducing agents leaves the need for safety measures. [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] S. Farhadi and F. Siadatnas, J. Mol. Catal. A: Chemical, 2011, 339, 108. [Non-Patent Document 2] MB Gawande, AK Rathi, PS Branco, ID Nogueira, A. Velhinho, JJ Shrikhande, UU Indulkar, RV Jayaram, C. Ghumman, N. Bundaleski and O. Teodoro, Chem. Eur. J. 2012, 18, 12628 [Non-Patent Document 3] H. Min, S. Lee, M. Park, J. Hwang, HM Jung and S. Lee, J. Organometallic Chem. 2014, 755, 7 [Overview of the project] [Problems that the invention aims to solve]

[0006] Therefore, the inventors focused on using polysaccharides such as cellulose or polyols, which are abundant in nature, as a safe hydrogen source for reducing reducible substances. By utilizing the α-hydrogen atoms of hydroxyl groups, which are abundant in naturally derived polysaccharides and polyols, the inventors aimed to develop a catalyst system for hydrogen transfer reactions to reducible substances.

[0007] However, extracting hydrogen from highly stable polysaccharides such as cellulose required heating to over 250°C, or the use of expensive ionic liquid homogeneous catalysts to dissolve these polysaccharides.

[0008] Furthermore, despite being safe, inexpensive, and possessing abundant hydroxyl groups, polyols have been used in applications such as raw materials for polyurethanes and polyesters, antifreeze, dispersants, thickeners, adhesives, and surfactants, but their use as a hydrogen source had not been found.

[0009] Therefore, from an environmental perspective, there has been a need for a method to extract hydrogen from highly stable polysaccharides and polyols such as cellulose using safe and inexpensive reagents under lower heating conditions, and to easily utilize the extracted hydrogen.

[0010] The present invention aims to provide a method for producing anilines by reducing aromatic nitro compounds, which are reducible substances, using polysaccharides such as cellulose or polyols as reducing agents, and for producing anilines under safe aqueous solvent conditions. [Means for solving the problem]

[0011] The inventors have developed a technology that utilizes polysaccharides such as cellulose or polyols as a hydrogenation source, using safe and inexpensive water as a solvent and an easy-to-handle solid catalyst. This technology is extremely simple because the hydrogen transfer reaction proceeds only by heating and stirring the polysaccharide or polyol, catalyst, reducible substance, and water.

[0012] As a result of diligent research to solve the above problems, the inventors have found that by creating a gold-supported catalyst, which is a gold nanoparticle immobilized catalyst obtained by supporting gold nanoparticles on a crystalline solid support, it is possible to extract hydrogen from polysaccharides such as cellulose or polyols in an aqueous solvent in the presence of the gold-supported catalyst to create active hydrogen species, and then react these with aromatic nitro compounds to produce anilines, making it an excellent catalyst.

[0013] Furthermore, the inventors have discovered that a gold-supported catalyst, which is a gold nanoparticle immobilized catalyst obtained by supporting gold nanoparticles on a crystalline solid support, is an excellent catalyst capable of producing hydrogen gas by dehydrogenating polysaccharides such as cellulose or polyols in an aqueous solvent.

[0014] That is, the present invention provides a gold-supported catalyst used for reducing a reducible substance using a polysaccharide or a polyol as a hydrogen source, a method for producing the catalyst, a method for producing anilines using the catalyst, a gold-supported catalyst used for dehydrogenating a polysaccharide or a polyol in an aqueous solvent to generate hydrogen gas, a method for producing the catalyst, and a method for producing hydrogen gas using the catalyst.

[0015] That is, a preferred embodiment of the present invention provides a gold-supported catalyst described below. [1] A catalyst used for reducing a reducible substance using a hydrogen source substance, wherein the hydrogen source substance is a polysaccharide or a polyol, and zero-valent gold particles having a diameter of 10 nm or less are supported on the surface of a crystalline solid, characterized gold-supported catalyst. [2] A catalyst used for generating hydrogen gas by dehydrogenating a hydrogen source substance in a liquid phase, wherein the hydrogen source substance is a polysaccharide or a polyol, and zero-valent gold particles having a diameter of 10 nm or less are supported on the surface of a crystalline solid, characterized gold-supported catalyst.

[0016] In addition, a method for producing hydrogen gas using a gold-supported catalyst described below is provided. [3] A method for generating hydrogen gas by reacting the gold-supported catalyst of [1] or [2] with a hydrogen source substance.

[0017] In addition, a method for producing anilines using a gold-supported catalyst described below is provided. [4] A method for producing anilines by reducing an aromatic nitro compound using a hydrogen source obtained by reacting the gold-supported catalyst of [1] or [2] with a hydrogenated substance. [Advantages of the Invention]

[0018] According to the present invention, it is possible to provide a gold-supported catalyst for reducing a reducible substance using polysaccharides or polyols as a hydrogenation source, a method for producing the catalyst, and a method for producing anilines using the catalyst. Furthermore, it is possible to provide a gold-supported catalyst for generating hydrogen gas by dehydrogenating polysaccharides or polyols in an aqueous solvent, and a method for producing hydrogen gas using the catalyst. [Brief explanation of the drawing]

[0019] [Figure 1] This image shows the TEM observation results of the gold nanoparticle immobilized catalyst from Manufacturing Example 1. [Figure 2] This image shows the TEM observation results of the gold nanoparticle immobilized catalyst from manufacturing example 6. [Modes for carrying out the invention]

[0020] [Gold-supported catalyst] One embodiment of the present invention is a gold-supported catalyst used for hydrogenating a reducible substance using polysaccharides or polyols as a hydrogenation source, wherein gold particles are supported on the surface of a crystalline solid.

[0021] Furthermore, one embodiment of the present invention is a gold-supported catalyst used to generate hydrogen gas by dehydrogenating polysaccharides or polyols in an aqueous solvent, wherein gold particles are supported on the surface of a crystalline solid.

[0022] In the present invention, the gold-supported catalyst used is a gold nanoparticle-immobilized catalyst obtained by immobilizing gold nanoparticles on the surface of a support.

[0023] (carrier) Examples of the carrier of the gold-supported catalyst in the present invention include inorganic crystalline carriers and activated carbon. Examples of the raw material of the inorganic crystalline carrier include metal oxides, layered clay minerals, fibrous clay minerals, and the like. Among them, from the viewpoint of significantly exhibiting the effects of the present invention, metal oxides or layered clay minerals are preferable. Examples of the metal oxide include alumina (Al2O3), titania (TiO2), and the like. Examples of the layered clay mineral include hydrotalcite and the like.

[0024] In addition, examples of the carrier of the gold-supported catalyst in the present invention include carriers having solid basicity. Specifically, hydrotalcite, alumina (Al2O3), titania (TiO2), and the like can be mentioned, and mixtures thereof may also be used. Hydrotalcite is preferable in that anilines can be obtained in the highest yield in the present invention. Hereinafter, a gold nanoparticle-immobilized catalyst using hydrotalcite having gold nanoparticles fixed on the surface of the hydrotalcite as a carrier may be referred to as "Au / HT".

[0025] As the hydrotalcite in the present invention, naturally produced hydrotalcite may be used, or synthetic hydrotalcite or synthetic hydrotalcite-like compounds may be used, and there is no particular limitation.

[0026] As the hydrotalcite in the present invention, commercially available products from companies such as Fuji Film Wako Chemical Co., Ltd. may be used.

[0027] Hydrotalcite is, for example, represented by the following formula (1) M II 8-X M III X (OH) 16 A·nH2O (1) (In the formula, M I I is at least one divalent metal selected from the group consisting of Mg 2+ Zn 2+ Ca 2+ Ni 2+ and Cu 2+ and MI I I is Al 3+ , Ga 3+ Fe 3+ , and Mn 3+ It is at least one trivalent metal selected from the group consisting of the following: x represents an integer from 1 to 7, A represents a divalent anion, and n represents an integer from 0 to 30. Alternatively, use the following formula (2) [Mg 2+ (1-y) Al 3+ y (OH)2] [(D s- ) y / s ·mH2O] (2) (In the formula, y represents a number that satisfies 0.20 ≤ y ≤ 0.33, D s- (where m represents an s-valence anion, and m represents an integer between 0 and 30.) It is represented as follows.

[0028] In this invention, the diameter of the carrier is the average value of the maximum lengths of 200 carrier particles, which are arbitrarily selected from the images obtained by observing primary particles using a transmission electron microscope (TEM).

[0029] The diameter of the carrier in the present invention can be, for example, 100 μm or less, 10 μm or less, 1 μm or less, 500 nm or less, 300 nm or less, etc. Also, it can be 10 nm or more, 50 nm or more, 100 nm or more, 200 nm or more, etc. Among these, from the viewpoint of significantly achieving the effects of the present invention, 100 μm or less is preferred, 10 μm or less is more preferred, 1 μm or less is even more preferred, and 500 nm or less is even more preferred. Also, 10 nm or more is preferred, 50 nm or more is more preferred, 100 nm or more is even more preferred, and 200 nm or more is even more preferred. Furthermore, 10 nm to 100 μm is preferred, 50 nm to 10 μm is more preferred, 100 nm to 1 μm is even more preferred, and 200 nm to 500 nm is even more preferred, but 50 nm to 1 μm, 80 nm to 600 μm, 100 nm to 500 nm, etc. are also acceptable.

[0030] (Gold nanoparticles) The gold particles in the gold nanoparticles used in this invention have a valence of 0.

[0031] The diameter of the gold nanoparticles used in the present invention can be, for example, 50 nm or less, 20 nm or less, 10 nm or less, 5 nm or less, 4 nm or less, etc. Also, 0.1 nm or more, 0.5 nm or more, 1 nm or more, 2 nm or more, 3 nm or more, etc. Among these, from the viewpoint of significantly achieving the effects of the present invention, 50 nm or less is preferred, 20 nm or less is more preferred, 10 nm or less is even more preferred, and 5 nm or less is even more preferred. Also, 0.5 nm or more is preferred, 1 nm or more is more preferred, 2 nm or more is even more preferred, and 3 nm or more is even more preferred. Furthermore, 0.5 nm to 50 nm is preferred, 1 nm to 20 nm is more preferred, 2 nm to 10 nm is even more preferred, and 3 nm to 5 nm is even more preferred, but 1 nm to 10 nm, 2 nm to 5 nm, etc. are also acceptable.

[0032] [Hydrogen source material] The hydrogenation source material used in the present invention is not limited to any compound having a hydroxyl group bonded to a primary or secondary carbon, but polysaccharides or polyols are preferred from the viewpoint of safety, cost, and environmental impact.

[0033] (polysaccharide) The polysaccharides used in the present invention are not limited to those mentioned above, but include, for example, cellulose, starch, and mixtures thereof. Among these, cellulose is preferred from the viewpoint of significantly exhibiting the effects of the present invention.

[0034] Furthermore, the polysaccharides used in this invention may be of natural origin or artificial origin, but from the viewpoint of environmental impact, naturally derived polysaccharides are preferred.

[0035] The structural formula of cellulose is shown in formula (3) below. The raw materials for cellulose used in the present invention are not limited, but examples include natural pulp, cotton linters, wood flour, and cotton waste. In the present invention, from the viewpoint of achieving the effects of the present invention, mercerized cellulose obtained by swelling natural pulp with an aqueous sodium hydroxide solution is preferred. [ka]

[0036] Furthermore, the polysaccharide used in the present invention may be cellulose nanofiber (CNF) derived from cellulose. Examples of CNF include, but are not limited to, TEMPO-oxidized cellulose.

[0037] The starch used in this invention includes, but is not limited to, horse potato starch, sweet potato starch, and corn starch. Furthermore, a starch with a low molecular weight is preferred.

[0038] (Polyols) The polyols used in the present invention are not limited to those mentioned above, but examples include glycerin, polyvinyl alcohol, and mixtures thereof.

[0039] The glycerin used in the present invention may include, but is not limited to, glycerin with a purity of 90% or higher.

[0040] The polyvinyl alcohol used in the present invention includes, but is not limited to, polyvinyl alcohol with a high degree of saponification. In particular, from the viewpoint of significantly achieving the effects of the present invention, a degree of saponification of 80 mol% or more is preferred, and 90 mol% or more is more preferred. Furthermore, it may also be a polyvinyl alcohol with a low degree of polymerization and a small molecular weight.

[0041] [Reducible substance] Examples of reducible substances in the present invention include aromatic nitro compounds.

[0042] (Aromatic nitro compounds) Examples of aromatic nitro compounds that serve as substrates for the alkene production method in the present invention include compounds represented by the following formula (4). [ka] In the formula, R1, R2, and R3 represent the same or different hydrogen atoms or hydrocarbon groups. R1 and R2, or two selected from R2 and R3, may be bonded to each other via carbon atoms to form a ring.

[0043] The hydrocarbon groups in R1, R2, and R3 of formula (3) are not particularly limited, but include, for example, aliphatic hydrocarbon groups, alicyclic hydrocarbon groups, aromatic hydrocarbon groups, and groups formed by combining these. The above hydrocarbon groups also include hydrocarbon groups having substituents.

[0044] Aliphatic hydrocarbon groups are not particularly limited, but examples include alkyl groups having about 1 to 10 carbon atoms (preferably 1 to 5 carbon atoms, more preferably 1 to 2 carbon atoms) such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, s-butyl, t-butyl, pentyl, and hexyl groups; alkenyl groups having about 2 to 10 carbon atoms (preferably 2 to 5 carbon atoms, more preferably 2 to 3 carbon atoms) such as vinyl, allyl, and butenyl groups; and alkynyl groups having about 2 to 10 carbon atoms (preferably 2 to 5 carbon atoms, more preferably 2 to 3 carbon atoms) such as ethynyl and propynyl groups.

[0045] The alicyclic hydrocarbon group is not particularly limited, but examples include cycloalkyl groups with 3 to 10 members (preferably 3 to 8 members, more preferably 5 to 6 members) such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and cyclooctyl groups; and cycloalkenyl groups with 3 to 10 members (preferably 3 to 6 members, more preferably 5 to 6 members) such as cyclopentenyl and cyclohexenyl groups.

[0046] Aromatic hydrocarbon groups are not particularly limited, but examples include aromatic hydrocarbon groups with approximately 6 to 14 carbon atoms, such as phenyl and naphthyl groups.

[0047] The hydrocarbon group formed by the bonding of an aliphatic hydrocarbon group and an alicyclic hydrocarbon group is not particularly limited, but examples include cycloalkyl-alkyl groups such as cyclopentylmethyl, cyclohexylmethyl, and 2-cyclohexylethyl (e.g., C3-20 cycloalkyl-C1-4 alkyl groups).

[0048] Furthermore, examples of monovalent hydrocarbon groups formed by the bonding of an aliphatic hydrocarbon group and an aromatic hydrocarbon group include aralkyl groups (e.g., C6-12 aralkyl groups) and alkyl-substituted aryl groups (e.g., phenyl or naphthyl groups substituted with about 1 to 4 C1-4 alkyl groups).

[0049] The hydrocarbon group described above may have various substituents, such as halogen atoms, oxo groups, hydroxyl groups, substituted oxy groups (e.g., alkoxy groups, aryloxy groups, aralkyloxy groups, acyloxy groups, etc.), carboxyl groups, substituted oxycarbonyl groups (alkoxycarbonyl groups, aryloxycarbonyl groups, aralkyloxycarbonyl groups, etc.), substituted or unsubstituted carbamoyl groups, cyano groups, nitro groups, acyl groups, substituted or unsubstituted amino groups, sulfo groups, heterocyclic groups, etc., but is not limited to these.

[0050] [Method for manufacturing gold-supported catalyst] There are no particular limitations on the method for immobilizing gold nanoparticles on the surface of a support such as hydrotalcite. For example, one method can be used in which an aqueous solution of a water-soluble gold compound such as sodium chloraurate (NaAuCl4) is mixed with hydrotalcite powder in water, and the mixture is stirred while adjusting the pH to about 9 with ammonia to support the gold hydroxide compound on the hydrotalcite surface by a precipitation-precipitation method, and then reduced by an appropriate method. The precipitation-precipitation method is the method described in Production Example 1 below, but is not limited thereto.

[0051] The polysaccharides or polyols of the present invention, as well as the carrier, gold nanoparticles, reducible substance, and aromatic nitro compound, are the same as those described in the section on [Gold-Supported Catalysts] above.

[0052] The water-soluble gold compound used in the immobilization treatment of gold nanoparticles is not particularly limited, but examples include aqueous solutions of sodium chloraurate (NaAuCl4), chlorauric acid (HAuCl4), potassium goldcyanide, potassium gold cyanide, sodium gold sulfite, and dichloro(1,10-phenanthroline) gold(III) chloride. Among these, aqueous solutions of chlorauric acid and sodium chloraurate are preferred from the viewpoint of significantly exhibiting the effects of the present invention, and aqueous solutions of chlorauric acid are more preferred.

[0053] The concentration of the water-soluble gold compound used when immobilizing gold nanoparticles onto the support is not particularly limited, but can be appropriately selected from, for example, a range of 0.01 to 100 mM.

[0054] In the gold nanoparticle immobilized catalyst, the ratio of support to gold nanoparticles is preferably 0.001 to 1 mmol per 1 g of support, more preferably 0.03 to 0.7 mmol, and even more preferably 0.1 to 0.5 mmol.

[0055] Examples of reducing agents used in the method for producing gold nanoparticle immobilized catalysts include boron hydride compounds such as sodium borohydride (NaBH4), hydrogen (H2) gas, and alcohol compounds. Examples of alcohol compounds include primary alcohols, secondary alcohols, and polyols, but are not limited to these.

[0056] The stirring temperature in the above precipitation-precipitation method can be selected from, for example, a range of 10 to 60°C, but is usually performed at room temperature (25°C). The stirring time varies depending on the temperature during stirring, but is, for example, 2 to 24 hours, preferably 8 to 12 hours. After stirring is complete, the mixture may be washed with water as needed and dried by vacuum drying or other methods. The vacuum drying time is adjusted appropriately depending on the state of the substance to be vacuum dried, but is preferably 3 to 12 hours.

[0057] [Methods for producing anilines] The present invention relates to a method for producing anilines from aromatic nitro compounds using a gold-supported catalyst and polysaccharides or polyols as a hydrogenation source.

[0058] In one embodiment, when reducing aromatic nitro compounds to produce anilines, polysaccharides or polyols, as well as a gold-supported catalyst and a solvent are used.

[0059] The gold-supported catalyst, polysaccharides or polyols, and aromatic nitro compounds of the present invention are the same as those described in the section on [Gold-Supported Catalyst] above.

[0060] The present invention provides a method for producing anilines by reducing an aromatic nitro compound in the presence of a polysaccharide or polyol and a gold-supported catalyst.

[0061] When the compound represented by formula (4) above is used as the aromatic nitro compound, the corresponding anilines represented by formula (5) below are obtained. The resulting anilines depend on the aromatic nitro compound that is reduced. [ka] In the formula, R1, R2, and R3 represent the same or different hydrogen atoms or hydrocarbon groups. R1 and R2, or two selected from R2 and R3, may be bonded to each other via carbon atoms to form a ring.

[0062] The reaction represented by formula (5) in the method for producing anilines according to the present invention is carried out in the liquid phase. Examples of solvents include water; ethers such as 1,2-dioxane, 1,3-dioxane, 1,4-dioxane, tetrahydrofuran, and tetrahydropyran; amides such as acetamide, dimethylacetamide, dimethylformamide, diethylformamide, and N-methylpyrrolidone; organic sulfur compounds such as dimethyl sulfoxide; and mixtures thereof.

[0063] (solvent) As the solvent used in the method for producing anilines according to the present invention, water is preferred from the viewpoint of significantly exhibiting the effects of the present invention.

[0064] (water) The water used as a solvent in the method for producing anilines according to the present invention may be ion-exchanged water, pure water, ultrapure water, RO water, etc., but is not particularly limited.

[0065] The amount of solvent used is preferably in a range where the substrate concentration is approximately 0.1 to 20% by mass, more preferably 0.5 to 10% by mass, and even more preferably 1 to 5% by mass.

[0066] In the present invention, the amount of reaction gold-supported catalyst represented by formula (5) is preferably about 0.1 to 50 mol%, and more preferably about 1 to 20 mol%, relative to the total amount of the aromatic nitro compound solution.

[0067] The method for producing anilines according to the present invention is not limited to, but can be carried out under an inert gas atmosphere. Argon or nitrogen are preferred as the inert gas.

[0068] The reaction represented by formula (5) in the present invention can be carried out by known methods such as batch, semi-batch, or continuous methods.

[0069] The reaction represented by formula (5) in the present invention can proceed smoothly even under mild conditions. The reaction temperature can be appropriately adjusted depending on the type of solute and the type of aniline. In particular, from the viewpoint of significantly exhibiting the effects of the present invention, a temperature of 200°C or less is preferred, 180°C or less is more preferred, and 150°C is even more preferred. Furthermore, a temperature of 10°C or higher is preferred, 50°C or higher is more preferred, and 80°C or higher is even more preferred. Moreover, a temperature of 10 to 200°C is preferred, 50 to 180°C is more preferred, and 80 to 150°C is even more preferred.

[0070] The reaction represented by formula (5) in the present invention is not particularly limited, but can be carried out under normal pressure or under pressurized pressure.

[0071] The reaction time of the reaction represented by formula (5) in the present invention can be appropriately adjusted according to the reaction temperature and pressure. In particular, from the viewpoint of significantly exhibiting the effects of the present invention, a reaction time of about 10 minutes to 48 hours is preferred, about 1 hour to 48 hours is more preferred, and about 2 to 8 hours is even more preferred.

[0072] After the reaction represented by formula (5) in the present invention is completed, the reaction product can be separated and purified by known separation methods such as filtration, concentration, distillation, extraction, crystallization, recrystallization, column chromatography, or a combination thereof.

[0073] Furthermore, since the gold nanoparticles of the gold-supported catalyst used in the reaction shown in formula (5) above are supported on a carrier, the supported gold nanoparticles do not easily leach into the reaction solution even in organic synthesis reactions. Therefore, the gold-supported catalyst can be easily recovered from the reaction solution by known separation methods such as filtration and / or centrifugation.

[0074] (Aniline compounds) In the present invention, when a compound represented by formula (4) is used as the aromatic nitro compound, the corresponding aniline represented by formula (5) is obtained.

[0075] The present invention includes the following embodiments. [1] A catalyst used to reduce a reducible substance using a hydrogenation source material, The hydrogenation source substance is a polysaccharide or a polyol. A gold-supported catalyst characterized by having zero-valent gold particles with a diameter of 10 nm or less supported on the surface of a crystalline solid. [2] The catalyst according to [1], wherein the polysaccharide is cellulose and / or starch. [3] The catalyst according to [1], wherein the polyols are glycerin and / or polyvinyl alcohol. [4] The catalyst according to [1], wherein the reducible substance is an aromatic nitro compound represented by the following formula (4). [ka] However, in the formula, R1, R2, and R3 represent the same or different hydrogen atoms or hydrocarbon groups. R1 and R2, or two selected from R2 and R3, may be bonded to each other via carbon atoms to form a ring. [5] A method for producing anilines from aromatic nitro compounds using the catalyst described in [1], with polysaccharides or polyols as a hydrogenation source. [6] The method according to [5], wherein the polysaccharide is cellulose and / or starch. [7] The method according to [5], wherein the polyols are glycerin and / or polyvinyl alcohol. [8] A catalyst used to generate hydrogen gas by dehydrogenating a hydrogenation source substance in the liquid phase, The hydrogenation source substance is a polysaccharide or a polyol. A gold-supported catalyst characterized by having zero-valent gold particles with a diameter of 10 nm or less supported on the surface of a crystalline solid. [9] The catalyst according to [8], wherein the polysaccharide is cellulose and / or starch.

[10] The catalyst according to [8], wherein the polyols are glycerin and / or polyvinyl alcohol.

[11] A method for producing hydrogen gas from polysaccharides or polyols in a liquid phase at 200°C or below, using the catalyst described in [8].

[12] A method for producing hydrogen gas by reacting a gold-supported catalyst [1] or [8] with a hydrogenation source material.

[13] A method for producing anilines by reducing aromatic nitro compounds using a hydrogen source obtained by reacting a gold-supported catalyst of [1] or [8] with a hydrogenated substance. [Examples]

[0076] The present invention will be described more specifically below with reference to examples, but the present invention is not limited to these examples.

[0077] [Test Example 1: Manufacturing of Each Catalyst] (Manufacturing Example 1) (1) 0.1 mmol of sodium chloride aurate (NaAuCl4) and 50 mL of deionized water were added to a 50 mL round-bottom flask, and 1.0 g of hydrotalcite (300 nm in diameter, manufactured by Fujifilm Wako Chemical Co., Ltd.) was added to the solution. Then, 0.1 mL of 28% by mass aqueous ammonia solution was added. (2) The mixture was then stirred at room temperature in an air atmosphere for 6 hours. (3) After stirring, the supernatant was removed by decantation. (4) Subsequently, distilled water was added and decanted repeatedly, and the precipitate was washed with a total of 1 L of distilled water. Then, ion-exchanged water (50 mL) was added, and 10 mL of 100 mM NaBH4 aqueous solution was added while stirring, and the mixture was stirred at room temperature for 1 hour. (5) After stirring, the mixture was filtered by suction, washed with 1 L of deionized water, and vacuum-dried at room temperature for 12 hours to obtain a purple powder of Au / HT (a hydrotalcite-supported gold nanoparticle immobilized catalyst with gold nanoparticles fixed to the hydrotalcite surface) (amount of gold per 1 g of support: 0.1 mmol / g). The immobilized gold nanoparticles were 0 valent and had a diameter of approximately 3 nm.

[0078] (Manufacturing example 2) (1) 0.1 mmol of silver nitrate (AgNO3) and 50 mL of deionized water were added to a 50 mL round-bottom flask, and 1.0 g of hydrotalcite (300 nm in diameter, manufactured by Fujifilm Wako Chemical Co., Ltd.) was added to the solution. (2) The mixture was then stirred at room temperature in an air atmosphere for 6 hours. (3) After stirring, the supernatant was removed by decantation. (4) Subsequently, distilled water was added and decanted repeatedly, and the precipitate was washed with a total of 1 L of distilled water. Water (50 mL) was added and 10 mL of 100 mM NaBH4 aqueous solution was added while stirring, and the mixture was stirred at room temperature for 1 hour. (5) After stirring, the mixture was filtered by suction, washed with 1 L of deionized water, and vacuum-dried at room temperature for 12 hours to obtain a green powder of Ag / HT (hydrotalcite-supported silver nanoparticle catalyst with silver nanoparticles immobilized on the hydrotalcite surface) (amount of silver per 1 g of support: 0.1 mmol / g). The immobilized silver nanoparticles were 0 valence and had a diameter of approximately 10 nm.

[0079] (Manufacturing Example 3) A gray powder of Pt / HT (a platinum nanoparticle immobilized catalyst using hydrotalcite as a support, in which platinum nanoparticles are immobilized on the surface of hydrotalcite) (amount of platinum per 1g of support: 0.1 mmol / g) was obtained in the same manner as in Production Example 2, except that H2PtCl6 was used instead of silver nitrate (AgNO3) as in Production Example 2. The immobilized platinum nanoparticles were 0 valent.

[0080] (Manufacturing example 4) A gray powder Pd / HT (palladium nanoparticle immobilized catalyst using hydrotalcite as a support, with palladium nanoparticles immobilized on the surface of hydrotalcite) (amount of palladium per 1g of support: 0.1 mmol / g) was obtained in the same manner as in Production Example 2, except that Na2PdCl4 was used instead of silver nitrate (AgNO3) as in Production Example 2. The immobilized palladium nanoparticles were 0 valent.

[0081] (Manufacturing example 5) A catalyst (Au / Al2O3) with gold nanoparticles immobilized on the alumina surface was obtained in the same manner as in Production Example 1, except that alumina (Al2O3) with a diameter of 200 nm was used instead of hydrotalcite.

[0082] (Manufacturing example 6) A catalyst (Au / TiO2) with gold nanoparticles immobilized on the titania surface was obtained in the same manner as in Production Example 1, except that titania (TiO2) with a diameter of 30 nm was used instead of hydrotalcite.

[0083] (Manufacturing example 7) A catalyst (Au / MgO) with gold nanoparticles immobilized on the surface of magnesia was obtained in the same manner as in Production Example 1, except that magnesia (MgO) with a diameter of 500 nm was used instead of hydrotalcite.

[0084] [Test Example 2: Production of anilines using each catalyst] (Example 1) (1) In a glass pressure-resistant reaction tube, the Au / HT (Au: 5 mol%) obtained in Production Example 1, 5 mL of deionized water, 1 mmol of mercerized cellulose, 0.2 mmol of nitrobenzene, and 1.5 mmol of Na2CO3 were added and stirred at 150°C for 3 hours under an argon atmosphere. (2) After stirring, the mixture was allowed to cool to room temperature, and octane was added to extract the organic matter and obtain aniline (nitrobenzene conversion rate 99% or more, aniline yield 30%, selectivity 30%). (3) In addition, azobenzene, hydrazobenzene, and nitrosobenzene were obtained as by-products after the reaction. The yield and selectivity were measured using a calibration curve method by gas chromatography, and the by-products were analyzed using gas chromatography-mass spectrometry.

[0085] The nitrobenzene conversion rate, aniline yield, and selectivity can be calculated using the following formulas, respectively. Nitrobenzene conversion rate (%) = 100 - (Amount of nitrobenzene after reaction (mol) / Amount of nitrobenzene used (mol) × 100) Aniline yield (%) = Amount of aniline produced (mol) / Amount of nitrobenzene used (mol) × 100 Selectivity (%) = (Aniline yield / Nitrobenzene conversion rate) × 100

[0086] The measurement conditions for gas chromatography are as follows:

[0087] [Gas chromatography measurement conditions] GC-MS analyzer: Agilent's "GC6890" / JEOL's "JMS-Q1050GC" Separation column: Agilent DB-5ms Carrier gas: Helium Inlet temperature: 250℃ Column temperature: 40°C (hold for 1 minute), increase temperature at -10°C / min to -280°C MS scan range: 10-500amu

[0088] (Example 2) The reaction conditions were the same as in Example 1, except that mercerized cellulose was replaced with wood pulp, and aniline was obtained (nitrobenzene conversion rate 67%, aniline yield 10%, selectivity 15%). Azobenzene, hydrazobenzene, and nitrosobenzene were obtained as by-products.

[0089] (Example 3) The reaction conditions were the same as in Example 2, except that the catalyst was changed from Au / HT obtained in Production Example 1 to Au / TiO2 obtained in Production Example 6, to obtain aniline (nitrobenzene conversion rate 47%, aniline yield 7%, selectivity 15%). Azobenzene, hydrazobenzene, and nitrosobenzene were obtained as by-products.

[0090] (Example 4) The reaction conditions were the same as in Example 2, except that the catalyst was changed from Au / HT obtained in Production Example 1 to Au / Al2O3 obtained in Production Example 5, to obtain aniline (nitrobenzene conversion rate 45%, aniline yield 6%, selectivity 13%). Azobenzene, hydrazobenzene, and nitrosobenzene were obtained as by-products.

[0091] (Example 5) The reaction conditions were the same as in Example 2, except that the catalyst was changed from Au / HT obtained in Production Example 1 to Au / MgO obtained in Production Example 7, to obtain aniline (nitrobenzene conversion rate 36%, aniline yield 5%, selectivity 14%). Azobenzene, hydrazobenzene, and nitrosobenzene were obtained as by-products.

[0092] (Example 6) In a pressure-resistant reaction tube, the Au / HT mixture obtained in Production Example 1 (Au: 1 mol% relative to cellulose), 5 mL of water, 1 mmol of mercerized cellulose, and 1.5 mmol of Na2CO3 were added and stirred at 150°C for 3 hours under an argon atmosphere. After the reaction was complete, the gas phase was analyzed by gas chromatography to confirm the presence of H2 gas.

[0093] (Example 7) The procedure was carried out in the same manner as in Example 1, except that cellulose nanofiber (CNF) (Nippon Paper Industries Co., Ltd., Selenpia®, TEMPO-oxidized cellulose 1 wt%) was used instead of mercerized cellulose, and aniline was obtained (nitrobenzene conversion rate 52%, aniline yield 7%, selectivity 14%).

[0094] (Example 8) The reaction conditions were the same as in Example 1, except that mercerized cellulose was replaced with starch (Nacalai Tesque Co., Ltd., soluble starch), to obtain aniline (nitrobenzene conversion rate 99% or higher, aniline yield 60%, selectivity 60%). Azobenzene, hydrazobenzene, and nitrosobenzene were obtained as by-products.

[0095] (Example 9) The reaction conditions were the same as in Example 1, except that mercerized cellulose was replaced with glycerin, to obtain aniline (nitrobenzene conversion rate 99% or higher, aniline yield 95%, selectivity 95%). Azobenzene, hydrazobenzene, and nitrosobenzene were obtained as by-products.

[0096] (Example 10) The reaction conditions were the same as in Example 1, except that mercerized cellulose was replaced with polyvinyl alcohol, to obtain aniline (nitrobenzene conversion rate 72%, aniline yield 45%, selectivity 62%). Azobenzene, hydrazobenzene, and nitrosobenzene were obtained as by-products.

[0097] (Comparative Example 1) The process was the same as in Example 2, except that Ag / HT obtained in Production Example 2 was used instead of Au / HT obtained in Production Example 1, but only a trace amount of aniline was obtained.

[0098] (Comparative Example 2) The process was the same as in Example 2, except that Pt / HT obtained in Production Example 3 was used instead of Au / HT obtained in Production Example 1, but aniline was not obtained.

[0099] (Comparative Example 3) The process was the same as in Example 2, except that Pd / HT obtained in Production Example 4 was used instead of Au / HT obtained in Production Example 1, but aniline was not obtained.

[0100] (Comparative Example 4) The process was the same as in Example 2, except that only hydrotalcite (HT) was used instead of the Au / HT obtained in Production Example 1, but aniline was not obtained.

[0101] (Comparative Example 5) The procedure was the same as in Example 2, except that the reaction was carried out without a catalyst, but aniline was not obtained.

[0102] (Comparative Example 6) The procedure was the same as in Example 1, except that the reaction was carried out without a catalyst, but aniline was not obtained.

[0103] The results for Examples 1-5 and 6-10, and Comparative Examples 1-6 are shown in Table 1 below.

[0104] [Table 1] [Industrial applicability]

[0105] The gold-supported catalyst of the present invention, which can be used to produce aromatic compounds containing useful amino bonds as intermediates in various pharmaceuticals, agricultural chemicals, food products, and other industrial fields, is useful because it can use naturally abundant polysaccharides and polyols as a hydrogen source, which are safe.

Claims

1. A catalyst used to reduce a reducible substance using a hydrogenation source material, The hydrogenation source substance is a polysaccharide or a polyol. A gold-supported catalyst characterized in that zero-valent gold particles with a diameter of 10 nm or less are supported on the surface of a crystalline solid.

2. A catalyst used to generate hydrogen gas by dehydrogenating a hydrogenation source substance in the liquid phase, The hydrogenation source substance is a polysaccharide or a polyol. A gold-supported catalyst characterized in that zero-valent gold particles with a diameter of 10 nm or less are supported on the surface of a crystalline solid.

3. A method for generating hydrogen gas by reacting a gold-supported catalyst according to claim 1 or 2 with a hydrogenation source material.

4. A method for producing anilines by reducing an aromatic nitro compound using a hydrogen source obtained by reacting a gold-supported catalyst according to claim 1 or 2 with a hydrogenated substance.

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