Method for producing aldehyde and catalyst composition

Abstract

To provide a novel aldehyde production method that yields an aldehyde by oxidation of an alcohol using hydrogen peroxide that is produced by an electrode reaction-based process.SOLUTION: A method for producing an aldehyde, comprising a reaction step of obtaining the aldehyde by reacting hydrogen peroxide and an alcohol in the presence of a catalyst group, wherein the hydrogen peroxide is hydrogen peroxide in a reaction solution produced by an electrode reaction, and the catalyst group comprises: one or more metal-based non-oxide solid catalysts selected from the group consisting of a platinum-based non-oxide solid catalyst, a ruthenium-based non-oxide solid catalyst, a palladium-based non-oxide solid catalyst, and an iridium-based non-oxide solid catalyst; and a metal oxide catalyst.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a method for producing aldehyde and a catalyst composition.

Background Art

[0002] Aldehyde is a functional chemical used as an intermediate raw material for medical and agricultural chemicals, various organic chemicals, fragrances, etc. Since ancient times, it has been produced by oxidizing alcohol using an oxidizing agent containing heavy metals. As other methods for producing aldehyde, a production method using a chlorine-based oxidizing agent in the presence of a radical catalyst (see Patent Document 1) and a production method using hypervalent iodine as an oxidizing agent (Non-Patent Document 1) are known. According to these methods, aldehyde can be produced in high yield.

[0003] Hydrogen peroxide is known as a clean oxidizing agent in which the co-product is only water and the effective oxygen efficiency is high. A method for producing α,β-unsaturated aldehyde by using hydrogen peroxide as an oxidizing agent and platinum black as a catalyst is disclosed (see Patent Document 2).

[0004] As a method for producing hydrogen peroxide, the anthraquinone method is well known. As an alternative production method, a method for producing hydrogen peroxide by immersing an aqueous solution of carbonates in an anode and performing an electrode reaction has been known so far. (See Patent Document 3, Non-Patent Documents 2 to 3).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Non-Patent Documents

[0006] [Non-Patent Document 1] D. B. Dess et al., J. Org. Chem. 1983, 48, pp.4155-4156. [Non-Patent Document 2] H.Wang et al., Nat. Commun. 2022, 13, 2668. [Non-Patent Document 3] X. Zheng et al., Nat. Commun. 2022, 13, 7256. [Summary of the Invention] [Problems to be Solved by the Invention]

[0007] In the production method using an oxidizing agent containing the above heavy metals, heavy metal wastes such as chromium and manganese are generated as co-products of the oxidation reaction. Therefore, from the viewpoint of safety, this production method is not preferable. In the production method described in Patent Document 1, a chlorine-based compound is generated as a co-product of the oxidation reaction, and furthermore, since the catalyst dissolves in the solution, it is also difficult to recover and reuse it. From the viewpoint of not having a small environmental impact, this production method is not preferable. The production method described in Non-Patent Document 1 generates iodine compounds as wastes, so it is not preferable from the viewpoint of not having a small environmental impact. In the production method described in Patent Document 2, although the co-product of the oxidation reaction is only water and thus the environmental impact is small, the anthraquinone method using a huge plant is used for the production of hydrogen peroxide, which requires a large amount of energy.

[0008] Hydrogen peroxide produced by a method using an electrode reaction as described in Patent Document 3 and the like has not been used for the production of aldehydes by the oxidation of alcohols so far. The reason is that hydrogen peroxide produced by this method is obtained as an aqueous hydrogen peroxide solution containing a large amount of carbonate, and the concentration of the hydrogen peroxide is 100 mM or less, which is low. The concentration of hydrogen peroxide in the aqueous hydrogen peroxide solution produced by the anthraquinone method is about 10 M. In comparison, when using an electrode reaction, the concentration of hydrogen peroxide is 1 / 100 or less, and aldehydes cannot be efficiently produced as it is.

[0009] An object of the present invention is to provide a novel method for producing aldehydes, which uses hydrogen peroxide produced by a method using an electrode reaction to obtain aldehydes by the oxidation of alcohols.

Means for Solving the Problems

[0010] To solve the above problems, the present invention adopts the following configuration. [1] A method for producing aldehydes having a reaction step of obtaining aldehydes by reacting hydrogen peroxide and alcohol in the presence of a catalyst group, wherein the hydrogen peroxide is hydrogen peroxide in a reaction solution obtained by an electrode reaction, and as the catalyst group, a platinum-based non-oxide solid catalyst, a ruthenium-based non-oxide solid catalyst, a palladium-based non-oxide solid catalyst, and an iridium-based non-oxide solid catalyst are used. A method for producing aldehydes using one or more metal-based non-oxide solid catalysts selected from the group consisting of, and a metal oxide catalyst. [2] The method for producing aldehydes according to [1], wherein the metal-based non-oxide solid catalyst is platinum black. [3] The method for producing aldehydes according to [1] or [2], wherein the metal oxide catalyst is one or more selected from the group consisting of magnesium oxide, silicon dioxide, titanium dioxide, aluminum oxide, cerium(IV) oxide, and zirconium dioxide.

[0011] [4] In the reaction step, the reaction temperature during the reaction of the hydrogen peroxide and the alcohol is 20°C to 100°C, and the method for producing an aldehyde according to any one of [1] to [3]. [5] The concentration of hydrogen peroxide in the reaction solution obtained by the electrode reaction is 10 to 100 mM, and the method for producing an aldehyde according to any one of [1] to [4]. [6] In the reaction step, the mass ratio of [the amount of the metal-based non-oxide solid catalyst used]: [the amount of the metal oxide catalyst used] is 1:1 to 1:21, and the method for producing an aldehyde according to any one of [1] to [5]. [7] The alcohol is represented by the following general formula (1)

[0012] [Chemical formula] (In the formula, R is an aliphatic hydrocarbon group having 1 to 10 carbon atoms or a hydrocarbon group containing an aromatic cyclic group, and one or more hydrogen atoms in the aliphatic hydrocarbon group and the hydrocarbon group containing an aromatic cyclic group may be substituted with fluorine atoms.) and is a compound represented by the formula, and the method for producing an aldehyde according to any one of [1] to [6]. [8] The aldehyde is represented by the following general formula (2)

[0013] [Chemical formula] (In the formula, R is an aliphatic hydrocarbon group having 1 to 10 carbon atoms or a hydrocarbon group containing an aromatic cyclic group, and one or more hydrogen atoms in the aliphatic hydrocarbon group and the hydrocarbon group containing an aromatic cyclic group may be substituted with fluorine atoms.) and is a compound represented by the formula, and the method for producing an aldehyde according to any one of [1] to [7].

[0014] [9] A catalyst composition for obtaining an aldehyde by reacting hydrogen peroxide with an alcohol, wherein the catalyst composition contains one or more metal-based non-oxide solid catalysts selected from the group consisting of a platinum-based non-oxide solid catalyst, a ruthenium-based non-oxide solid catalyst, a palladium-based non-oxide solid catalyst, and an iridium-based non-oxide solid catalyst, and a metal oxide catalyst.

[10] The catalyst composition according to [9], wherein the metal oxide catalyst is one or more selected from the group consisting of magnesium oxide, silicon dioxide, titanium dioxide, aluminum oxide, cerium(IV) oxide, and zirconium oxide. [Advantages of the Invention]

[0015] According to the present invention, there is provided a novel method for producing an aldehyde by oxidizing an alcohol using hydrogen peroxide produced by a method utilizing an electrode reaction. [Brief Description of the Drawings]

[0016]

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MODE FOR CARRYING OUT THE INVENTION

[0017] In this specification, the concentration unit "M" means "mol / L", and "mM" means "mmol / L".

[0018] In this specification, unless otherwise specified, the yield of the target product means the yield calculated by the following formula. [Yield of target product (%)] = [Amount of target product (mol)] / [Amount of raw material used (mol)] × 100

[0019] <<Method for Producing Aldehyde>> The method for producing an aldehyde according to an embodiment of the present invention has a reaction step of obtaining an aldehyde by reacting hydrogen peroxide (H2O2) and an alcohol in the presence of a catalyst group, wherein the hydrogen peroxide is hydrogen peroxide in a reaction solution obtained by an electrode reaction, and as the catalyst group, a platinum (Pt)-based non-oxide solid catalyst, a ruthenium (Ru)-based non-oxide solid catalyst, a palladium (Pd)-based non-oxide solid catalyst, and an iridium (Ir)-based non-oxide solid catalyst are used, and one or more metal-based non-oxide solid catalysts selected from the group consisting of, and a metal oxide catalyst are used. According to the production method of the present embodiment, by using the catalyst group, an aldehyde can be produced by a novel method of obtaining an aldehyde by oxidizing an alcohol using hydrogen peroxide produced by a method utilizing an electrode reaction. According to the production method of the present embodiment, an aldehyde can be produced inexpensively and simply.

[0020] In the reaction step, even if the metal-based non-oxide solid catalyst and the metal oxide catalyst are used in combination without performing special or complicated operations such as supporting them on a carrier, these catalysts cooperate to promote the oxidation reaction of the alcohol. On the other hand, a metal-based non-oxide solid catalyst supported on a metal oxide catalyst does not promote the oxidation reaction of the alcohol, or even if it does, the effect is low.

[0021] In this specification, the mere description of "catalyst" means either a metal-based non-oxide solid catalyst or a metal oxide catalyst unless otherwise specified.

[0022] <Alcohol> The alcohol, which is an object to be oxidized by hydrogen peroxide, is not particularly limited as long as it is a primary alcohol.

[0023] In the alcohol, a group other than a hydrogen atom bonded to the carbon atom to which the hydroxyl group (-OH) is bonded is preferably a hydrocarbon group that may have a substituent. The hydrocarbon group is a monovalent hydrocarbon group and has a structure in which one hydrogen atom is removed from a hydrocarbon. The hydrocarbon group may be either an aliphatic hydrocarbon group or an aromatic ring-containing hydrocarbon group, and may be either a saturated hydrocarbon group or an unsaturated hydrocarbon group.

[0024] Among the hydrocarbon groups, the saturated aliphatic hydrocarbon group (i.e., alkyl group) may be linear, branched, or cyclic, and may have both a chain structure (linear structure or branched structure) and a cyclic structure. Even when the saturated aliphatic hydrocarbon group is cyclic, when it has a cyclic structure, the cyclic structure may be either monocyclic or polycyclic. The number of carbon atoms of the saturated aliphatic hydrocarbon group is preferably 1 to 20, and more preferably 1 to 10.

[0025] In this specification, not limited to the case of the saturated aliphatic hydrocarbon group, the number of carbon atoms of the hydrocarbon group means the number of carbon atoms including the carbon atoms of the substituent when the hydrocarbon group has a substituent.

[0026] The number of carbon atoms of the linear or branched saturated aliphatic hydrocarbon group (alkyl group) is preferably 1 to 20. Examples of such chain-like saturated aliphatic hydrocarbon groups include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, isopentyl group, neopentyl group, tert-pentyl group, 1-methylbutyl group, n-hexyl group, 2-methylpentyl group, 3-methylpentyl group, 2,2-dimethylbutyl group, 2,3-dimethylbutyl group, n-heptyl group, 2-methylhexyl group, 3-methylhexyl group, 2,2-dimethylpentyl group, 2,3-dimethylpentyl group, 2,4-dimethylpentyl group, 3,3-dimethylpentyl group, 3-ethylpentyl group, 2,2,3-trimethylbutyl group, n-octyl group, isooctyl group, 2-ethylhexyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, icosyl group, and the like. The number of carbon atoms of the chain-like saturated aliphatic hydrocarbon group is more preferably 1 to 10, and may be, for example, any one of 1 to 8, 1 to 5, and 1 to 3.

[0027] The number of carbon atoms of the saturated aliphatic hydrocarbon group having a cyclic structure, such as the cyclic saturated aliphatic hydrocarbon group (cycloalkyl group), is preferably 3 to 20, and more preferably 3 to 10. Examples of such cyclic saturated aliphatic hydrocarbon groups include monocyclic or polycyclic saturated aliphatic hydrocarbon groups such as cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclononyl group, cyclodecyl group, norbornyl group, isobornyl group, 1-adamantyl group, 2-adamantyl group, tricyclodecyl group, and the like. Examples of the saturated aliphatic hydrocarbon group having both such a chain structure and a cyclic structure include monovalent groups having a structure in which one or more hydrogen atoms (-H) in the above linear or branched saturated aliphatic hydrocarbon group are substituted with the above cyclic saturated aliphatic hydrocarbon group. The number of carbon atoms in the saturated aliphatic hydrocarbon group having the cyclic structure is more preferably 3 to 10, and may be, for example, 5 to 10.

[0028] Among the hydrocarbon groups, the unsaturated aliphatic hydrocarbon group may be linear, branched or cyclic, and may have both a chain structure (linear structure or branched structure) and a cyclic structure. Even when the unsaturated aliphatic hydrocarbon group is cyclic, when it has a cyclic structure, the cyclic structure may be either monocyclic or polycyclic. The number of carbon atoms in the unsaturated aliphatic hydrocarbon group is preferably 2 to 20, and more preferably 2 to 10. The number of carbon atoms in the linear or branched unsaturated aliphatic hydrocarbon group is preferably 2 to 20, more preferably 2 to 10, and may be, for example, any of 2 to 8, 2 to 5, and 2 to 3. The number of carbon atoms in the unsaturated aliphatic hydrocarbon group having a cyclic structure is preferably 3 to 20, more preferably 3 to 10, and may be, for example, 5 to 10.

[0029] Examples of the unsaturated aliphatic hydrocarbon group include monovalent groups having a structure in which one or more single bonds (-) between carbon atoms in the above-mentioned chain (linear or branched) saturated aliphatic hydrocarbon group or saturated aliphatic hydrocarbon group having a cyclic structure are replaced by double bonds (=) or triple bonds (≡).

[0030] The unsaturated aliphatic hydrocarbon group may be a monovalent group having both a double bond between one or more carbon atoms and a triple bond between one or more carbon atoms, or a monovalent group having a triple bond between one or more carbon atoms and no double bond between carbon atoms, but it is preferably a monovalent group having a double bond between one or more carbon atoms and no triple bond between carbon atoms.

[0031] The total number of double bonds between carbon atoms and triple bonds between carbon atoms in the unsaturated aliphatic hydrocarbon group is not particularly limited, but is preferably 1 to 3, and may be, for example, 1 or 2, or may be 1.

[0032] Among the unsaturated aliphatic hydrocarbon groups, the number of carbon atoms in the monovalent group having a double bond between one carbon atom and no triple bond between carbon atoms, that is, the alkenyl group, is preferably 2 to 20, and more preferably 2 to 10.

[0033] The number of carbon atoms in the linear or branched alkenyl group is preferably 2 to 20, more preferably 2 to 10, and may be, for example, any of 2 to 8, 2 to 5, and 2 to 3. Examples of such a chain alkenyl group include ethenyl group (vinyl group), 2-propenyl group (allyl group), 1-methylethenyl group (isopropenyl group), 2-methylethenyl group (1-propenyl group), butenyl group, pentenyl group, hexenyl group, heptenyl group, octenyl group, nonenyl group, decenyl group, and the like.

[0034] The number of carbon atoms in the alkenyl group having a cyclic structure, such as the cyclic alkenyl group (cycloalkenyl group), is preferably 3 to 20, more preferably 5 to 10, and may be, for example, 6 to 10. Examples of such a cyclic alkenyl group include cyclopentenyl group, cyclohexenyl group, cycloheptenyl group, cyclooctenyl group, cyclononenyl group, cyclodecenyl group, and the like. Examples of the alkenyl group having both such a chain structure and a cyclic structure include a monovalent group having a structure in which one hydrogen atom (-H) in the above linear or branched saturated aliphatic hydrocarbon group is substituted with the above cyclic alkenyl group, and a monovalent group having a structure in which one hydrogen atom (-H) in the above linear or branched alkenyl group is substituted with the above cyclic saturated aliphatic hydrocarbon group.

[0035] Among the unsaturated aliphatic hydrocarbon groups, the monovalent group having a double bond between two carbon atoms and no triple bond between carbon atoms, that is, the carbon number of the alkadienyl group is preferably 4 to 20, and more preferably 4 to 10. Examples of the alkadienyl group include monovalent groups having a structure in which a single bond (-) between one carbon atom in the alkenyl group is replaced by a double bond (=).

[0036] The carbon number of the linear or branched alkadienyl group is preferably 4 to 20, more preferably 4 to 10, and may be, for example, 6 to 10. Examples of such a chain alkadienyl group include a 2,6-dimethyl-1,5-heptadienyl group.

[0037] The carbon number of the alkadienyl group having a cyclic structure, such as the cyclic alkadienyl group (cycloalkadienyl group), is preferably 4 to 20, more preferably 5 to 10, and may be, for example, 6 to 10.

[0038] Among the hydrocarbon groups, the aromatic ring-containing hydrocarbon group is a hydrocarbon group having at least an aromatic ring, a monovalent group consisting only of an aromatic ring (a monovalent group in which the carbon atoms constituting the aromatic ring have free valences, that is, an aryl group), or a monovalent group consisting of an aromatic ring and an aliphatic hydrocarbon group (one or more hydrogen atoms in a monovalent aliphatic hydrocarbon group are substituted with an aromatic ring, and the carbon atoms constituting the aliphatic hydrocarbon group have free valences). Regardless of the presence or absence of the aliphatic hydrocarbon group, the aromatic ring in the aromatic ring-containing hydrocarbon group may be either monocyclic or polycyclic. The carbon number of the aromatic ring-containing hydrocarbon group is preferably 6 to 20, and more preferably 6 to 15.

[0039] Regardless of the presence or absence of the aliphatic hydrocarbon group, examples of the aromatic cyclic group in the aromatic cyclic group-containing hydrocarbon group include a phenyl group, 1-naphthyl group, 2-naphthyl group, 4-methylphenyl group (p-tolyl group), 3-methylphenyl group (m-tolyl group), 2-methylphenyl group (o-tolyl group), 2,3-dimethylphenyl group (2,3-xylyl group), 2,4-dimethylphenyl group (2,4-xylyl group), 2,5-dimethylphenyl group (2,5-xylyl group), 2,6-dimethylphenyl group (2,6-xylyl group), 3,4-dimethylphenyl group (3,4-xylyl group), 3,5-dimethylphenyl group (3,5-xylyl group), 2,4,6-trimethylphenyl group (mesityl group), and the like. Regardless of the presence or absence of the aliphatic hydrocarbon group, examples of the aromatic cyclic group in the aromatic cyclic group-containing hydrocarbon group further include monovalent groups having a structure in which one or more hydrogen atoms in the above-described aromatic cyclic groups are substituted with the aromatic cyclic group or the aliphatic hydrocarbon group.

[0040] The number of carbon atoms of the aromatic cyclic group-containing hydrocarbon group having no aliphatic hydrocarbon group (the monovalent group consisting only of an aromatic cyclic group, an aryl group) is more preferably 6 to 15, and may be, for example, either 6 to 12 or 6 to 9.

[0041] Examples of the aliphatic hydrocarbon group in the monovalent group composed of an aromatic cyclic group and an aliphatic hydrocarbon group include those described above. Among the monovalent groups composed of an aromatic cyclic group and an aliphatic hydrocarbon group, those in which the aliphatic hydrocarbon group is a saturated aliphatic hydrocarbon group (i.e., an alkyl group) are arylalkyl groups, i.e., aralkyl groups. Examples of the aralkyl group include a benzyl group (phenylmethyl group), a phenethyl group (2-phenylethyl group), and the like.

[0042] The number of carbon atoms of the monovalent group composed of an aromatic cyclic group and an aliphatic hydrocarbon group is more preferably 7 to 15, and may be, for example, either 7 to 12 or 7 to 9.

[0043] The hydrocarbon group may or may not have a substituent. When the hydrocarbon group has a substituent, it means that one or more hydrogen atoms in the hydrocarbon group are substituted with a group (substituent) other than a hydrogen atom.

[0044] In this specification, unless otherwise specified, the term "group" includes not only an atomic group formed by bonding of a plurality of atoms but also a single atom.

[0045] Examples of the substituent that the hydrocarbon group has include halogen atoms such as a fluorine atom (-F), a chlorine atom (-Cl), a bromine atom (-Br), and an iodine atom (-I).

[0046] The halogen atom as the substituent is preferably a fluorine atom.

[0047] When the hydrocarbon group has a substituent, the number of substituents may be less than or equal to the number of hydrogen atoms that can be substituted, and all hydrogen atoms may be substituted with substituents. When the hydrocarbon group has a substituent, the number of substituents preferably ranges from 1 to 10, for example, any of 1 to 8, 1 to 6, 1 to 4, and 1 to 2, provided that the upper limit condition is satisfied.

[0048] The position of the substituent when the hydrocarbon group has a substituent is not particularly limited. For example, when the hydrocarbon group has two or more substituents, the number of substituents bonded to one carbon atom in the hydrocarbon group may be only one or two or more (2 to 3).

[0049] For example, when the hydrocarbon group can be regarded as having an alkyl group as part of its structure, only one of the hydrogen atoms in the alkyl group may be substituted with a substituent, two or more of them may be substituted with substituents, or all of them may be substituted with substituents. For example, in the alkyl group in which a hydrogen atom is substituted with a halogen atom, that is, the halogenated alkyl group, it may be either a monohaloalkyl group (an alkyl group in which the number of hydrogen atoms substituted by a halogen atom is 1) or a polyhaloalkyl group (an alkyl group in which the number of hydrogen atoms substituted by a halogen atom is 2 or more), and may be a perhaloalkyl group. Among such halogenated alkyl groups, those in which the halogen atom is a fluorine atom include, for example, a monofluoromethyl group (-CH2F), a difluoromethyl group (-CHF2), a trifluoromethyl group (-CF3), a pentafluoroethyl group (-C2F5), a heptafluoropropyl group (-C3F7), a nonafluorobutyl group (-C4F9), and the like.

[0050] When the hydrocarbon group has two or more substituents, these substituents may be the same as each other or different from each other. That is, two or more substituents may all be the same, all be different, or only some of them may be the same. When the hydrocarbon group has two or more substituents, the combination of these substituents is not particularly limited.

[0051] The alcohol is represented by the following general formula (1)

[0052]

Chemical formula

[0053] In the general formula (1), R corresponds to a group other than a hydrogen atom (i.e., a hydrocarbon group which may have a substituent) bonded to the carbon atom to which the hydroxyl group in the alcohol is bonded, as described above.

[0054] The aliphatic hydrocarbon group having 1 to 10 carbon atoms in R is a group having 1 to 10 carbon atoms among the aliphatic hydrocarbon groups as the hydrocarbon groups described above, which is its superordinate concept. The aliphatic hydrocarbon group having 1 to 10 carbon atoms in R may be either a saturated aliphatic hydrocarbon group (i.e., an alkyl group) having a linear or branched chain or a cyclic structure, or an unsaturated aliphatic hydrocarbon group having a linear or branched chain or a cyclic structure. The number of carbon atoms of the linear or branched saturated aliphatic hydrocarbon group in R is 1 to 10, and may be, for example, any of 1 to 8, 1 to 5, and 1 to 3. The number of carbon atoms of the saturated aliphatic hydrocarbon group having a cyclic structure in R is 3 to 10, and may be, for example, 5 to 10. The number of carbon atoms of the linear or branched unsaturated aliphatic hydrocarbon group in R is 2 to 10, and may be, for example, any of 2 to 8, 2 to 5, and 2 to 3. For example, the number of carbon atoms of a linear or branched alkenyl group is 2 to 10, and may be any of 2 to 8, 2 to 5, and 2 to 3. For example, the number of carbon atoms of a linear or branched alkadienyl group is 4 to 10, and may be 6 to 10. The number of carbon atoms of the unsaturated aliphatic hydrocarbon group having a cyclic structure in R is 3 to 10, and may be 5 to 10. For example, the number of carbon atoms of an alkenyl group having a cyclic structure is 3 to 10, and may be any of 5 to 10 and 6 to 10. For example, the number of carbon atoms of an alkadienyl group having a cyclic structure is 4 to 10, and may be any of 5 to 10 and 6 to 10.

[0055] The aromatic cyclic group-containing hydrocarbon group in R is the same as the aromatic cyclic group-containing hydrocarbon group as the hydrocarbon group described above, and may be either a monovalent group consisting only of an aromatic cyclic group (aryl group) or a monovalent group consisting of an aromatic cyclic group and an aliphatic hydrocarbon group. The preferred embodiments of the aromatic cyclic group-containing hydrocarbon group in R are the same as the preferred embodiments of the aromatic cyclic group-containing hydrocarbon group as the hydrocarbon group described above. Therefore, a detailed description of the aromatic cyclic group-containing hydrocarbon group in R will be omitted here.

[0056] One or more hydrogen atoms in the aliphatic hydrocarbon group in R and one or more hydrogen atoms in the aromatic cyclic group-containing hydrocarbon group may be substituted with fluorine atoms. In this case, the mode of substitution of hydrogen atoms with fluorine atoms in the aliphatic hydrocarbon group and the aromatic cyclic group-containing hydrocarbon group is the same as the mode of substitution of hydrogen atoms with halogen atoms in the aliphatic hydrocarbon group and the aromatic cyclic group-containing hydrocarbon group as the hydrocarbon group described above. Therefore, a detailed description of the aliphatic hydrocarbon group and the aromatic cyclic group-containing hydrocarbon group in R in which hydrogen atoms are substituted with fluorine atoms will be omitted here.

[0057] In the general formula (1), R is preferably an alkyl group having a linear, branched, or cyclic structure with 1 to 10 carbon atoms, an alkenyl group having a linear, branched, or cyclic structure with 2 to 10 carbon atoms, an alkadienyl group having a linear, branched, or cyclic structure with 4 to 10 carbon atoms, an aryl group with 6 to 15 carbon atoms, or an aralkyl group with 7 to 15 carbon atoms. One or more hydrogen atoms in the alkyl group, alkenyl group, alkadienyl group, aryl group, and aralkyl group may be substituted with fluorine atoms.

[0058] In the general formula (1), R is more preferably a linear or branched alkyl group having 1 to 10 carbon atoms, a linear or branched alkenyl group having 2 to 10 carbon atoms, a linear or branched alkadienyl group having 4 to 10 carbon atoms, an aryl group having 6 to 9 carbon atoms, or an aralkyl group having 7 to 9 carbon atoms. One or more hydrogen atoms in the alkyl group, alkenyl group, alkadienyl group, aryl group, and aralkyl group may be substituted with fluorine atoms.

[0059] In the general formula (1), R is even more preferably a linear or branched alkenyl group having 2 to 10 carbon atoms, a linear or branched alkadienyl group having 4 to 10 carbon atoms, or an aryl group having 6 to 9 carbon atoms. One or more hydrogen atoms in the alkenyl group, alkadienyl group, and aryl group may be substituted with fluorine atoms.

[0060] Particularly preferred examples of the alcohol (the preferred alcohol represented by the general formula (1)) include benzyl alcohol, 3-fluorobenzyl alcohol, 4-fluorobenzyl alcohol, 3,4-difluorobenzyl alcohol, (4-trifluoromethyl)benzyl alcohol, 2-octen-1-ol, geraniol, and the like.

[0061] The alcohol used in the reaction step may be only one kind or two or more kinds. When there are two or more kinds, their combinations and ratios can be arbitrarily selected according to the purpose.

[0062] <Catalyst group> In the reaction step, as the catalyst group, the metal-based non-oxide solid catalyst and the metal oxide catalyst are used. The metal-based non-oxide solid catalyst is presumed to promote dehydrogenation from alcohol in the reaction step. The metal oxide catalyst is presumed to smoothly promote the formation of aldehyde by promoting an increase in the concentration of hydrogen peroxide in the reaction solution in the reaction step.

[0063] Among the metal-based non-oxide solid catalysts, the platinum-based non-oxide solid catalyst contains platinum (Pt) as the metal constituting it and does not correspond to metal oxides such as platinum oxides, and is a solid catalyst in a solid state at normal temperature. The platinum-based non-oxide solid catalyst is preferably in particulate form.

[0064] Preferred platinum-based non-oxide solid catalysts include, for example, platinum black. Platinum black is fine black platinum powder, and its average particle size is preferably 200 μm or less. On the other hand, a platinum-based non-oxide solid catalyst with an average particle size of 1 μm or more can be more easily prepared or obtained.

[0065] In this specification, "average particle size" means, unless otherwise specified, the particle size (D 50 ) at the 50% cumulative value in the particle size distribution curve obtained by the laser diffraction scattering method.

[0066] In this specification, "normal temperature" means a temperature that is not particularly cooled or heated, that is, the normal temperature, and examples include temperatures in the range of 15 to 25°C.

[0067] Among the metal-based non-oxide solid catalysts, the ruthenium-based non-oxide solid catalyst contains ruthenium (Ru) as the metal constituting it and does not correspond to metal oxides such as ruthenium oxides, and is a solid catalyst in a solid state at normal temperature.

[0068] Preferred ruthenium-based non-oxide solid catalysts include, for example, ruthenium black. Ruthenium black is fine black ruthenium powder, and its average particle size is preferably in the same range as that of platinum black for the same reason as in the case of platinum black.

[0069] Among the metal-based non-oxide solid catalysts, the palladium-based non-oxide solid catalyst contains palladium (Pd) as the metal constituting it and does not correspond to metal oxides such as palladium oxides, and is a solid catalyst in a solid state at normal temperature.

[0070] Preferred palladium-based non-oxide solid catalysts include, for example, palladium black. Palladium black is a fine black palladium powder, and its average particle size is preferably in the same range as that of platinum black for the same reason as in the case of platinum black.

[0071] Among the metal-based non-oxide solid catalysts, the iridium-based non-oxide solid catalyst contains iridium (Ir) as the metal constituting it and does not correspond to metal oxides such as iridium oxides, and is a solid catalyst in a solid state at normal temperature.

[0072] Preferred iridium-based non-oxide solid catalysts include, for example, iridium black. Iridium black is a fine black iridium powder, and its average particle size is preferably in the same range as that of platinum black for the same reason as in the case of platinum black.

[0073] In terms of the reaction rate of alcohol and the production rate of aldehyde being higher, the metal-based non-oxide solid catalyst is preferably a platinum-based non-oxide solid catalyst, and more preferably platinum black.

[0074] That is, in the reaction step, it is preferable to use at least a platinum-based non-oxide solid catalyst as the metal-based non-oxide solid catalyst, and the larger the amount of the platinum-based non-oxide solid catalyst used, the more preferable it is, and the platinum-based non-oxide solid catalyst is preferably platinum black.

[0075] More specifically, in the reaction step, the ratio of the amount of the platinum-based non-oxide solid catalyst to the total amount of the metal-based non-oxide solid catalyst ([amount of the platinum-based non-oxide solid catalyst used in the reaction step (parts by mass)] / ([amount of the platinum-based non-oxide solid catalyst used in the reaction step (parts by mass)] + [amount of the ruthenium-based non-oxide solid catalyst used in the reaction step (parts by mass)] + [amount of the palladium-based non-oxide solid catalyst used in the reaction step (parts by mass)] + [amount of the iridium-based non-oxide solid catalyst used in the reaction step (parts by mass)]) × 100) is preferably 50% by mass or more, more preferably 70% by mass or more, still more preferably 80% by mass or more, and may be, for example, any of 90% by mass or more, 95% by mass or more, and 97% by mass or more. On the other hand, the ratio is 100% by mass or less.

[0076] In the reaction step, the ratio of the amount of platinum black to the amount of the platinum-based non-oxide solid catalyst ([amount of platinum black used in the reaction step (parts by mass)] / [amount of the platinum-based non-oxide solid catalyst used in the reaction step (parts by mass)] × 100) is preferably 50% by mass or more, more preferably 70% by mass or more, still more preferably 80% by mass or more, and may be, for example, any of 90% by mass or more, 95% by mass or more, and 97% by mass or more. On the other hand, the ratio is 100% by mass or less.

[0077] The metal oxide catalyst is a component different from the metal-based non-oxide solid catalyst and may be a known one for catalytic reaction.

[0078] Examples of the metal oxide catalyst include magnesium oxide (MgO), silicon dioxide (SiO2), titanium dioxide (TiO2), aluminum oxide (Al2O3), cerium(IV) oxide (CeO2), zirconium dioxide (ZrO2), and the like.

[0079] In terms of the reaction rate of alcohol and the production rate of aldehyde being higher, the metal oxide catalyst is preferably in particulate form at room temperature.

[0080] The specific surface area of the metal oxide catalyst (preferably a particulate metal oxide catalyst) is preferably 10 m 2 / g or more. When the specific surface area is at least the lower limit value, the reaction rate of alcohol and the production rate of aldehyde become higher. On the other hand, a metal oxide catalyst with a specific surface area of 200 m 2 / g or less is easier to prepare or obtain.

[0081] In terms of the reaction rate of alcohol and the production rate of aldehyde being higher, the average particle diameter of the metal oxide catalyst (preferably a particulate metal oxide catalyst) is preferably 100 - 3000 Å (angstroms) (being in fine particulate form).

[0082] The metal oxide catalyst used in the reaction step may be only one kind or two or more kinds. When there are two or more kinds, their combinations and ratios can be arbitrarily selected according to the purpose.

[0083] In terms of the reaction rate of alcohol and the production rate of aldehyde being higher and commercially available particulate products being easily obtainable, the metal oxide catalyst used in the reaction step is preferably one kind or two or more kinds selected from the group consisting of magnesium oxide, silicon dioxide, titanium dioxide, aluminum oxide, cerium(IV) oxide, and zirconium oxide.

[0084] In the reaction step, the ratio of the total amount of magnesium oxide, silicon dioxide, titanium dioxide, aluminum oxide, cerium(IV) oxide, and zirconium oxide to the total amount of the metal oxide catalyst used (([the amount of magnesium oxide used in the reaction step (parts by mass)] + [the amount of silicon dioxide used in the reaction step (parts by mass)] + [the amount of titanium dioxide used in the reaction step (parts by mass)] + [the amount of aluminum oxide used in the reaction step (parts by mass)] + [the amount of cerium(IV) oxide used in the reaction step (parts by mass)] + [the amount of zirconium oxide used in the reaction step (parts by mass)]) / [the total amount of the metal oxide catalyst used in the reaction step (parts by mass)] × 100) is preferably 50% by mass or more, more preferably 70% by mass or more, still more preferably 80% by mass or more, and may be, for example, any of 90% by mass or more, 95% by mass or more, and 97% by mass or more. When the ratio is at least the lower limit value, the reaction rate of the alcohol and the production rate of the aldehyde become higher. On the other hand, the ratio is 100% by mass or less.

[0085] In the reaction step, the mass ratio of [the amount of the solid catalyst of the non-oxide of the metal] : [the amount of the metal oxide catalyst] is preferably 1:1 to 1:21 in terms of the reaction rate of the alcohol and the production rate of the aldehyde being good, more preferably 1:2 to 1:12 in terms of the reaction rate of the alcohol and the production rate of the aldehyde being higher, still more preferably 1:2 to 1:8, and particularly preferably 1:2 to 1:6.

[0086] In the reaction step, the total usage amount of the metal-based non-oxide solid catalyst and the metal oxide catalyst per 1 mmol of the usage amount of alcohol (([Usage amount of the metal-based non-oxide solid catalyst (mg) in the reaction step] + [Usage amount of the metal oxide catalyst (mg) in the reaction step]) / [Usage amount of alcohol (mmol) in the reaction step]) is preferably 10 to 1400 mg, more preferably 100 to 1300 mg, and may be, for example, any one of 500 to 1300 mg, 750 to 1300 mg, and 1000 to 1300 mg. When the total usage amount is at least the lower limit value, the reaction rate of alcohol and the production rate of aldehyde become higher. When the total usage amount is at most the upper limit value, excessive use of the catalyst group is suppressed.

[0087] <Hydrogen peroxide> In the reaction step, as the hydrogen peroxide, hydrogen peroxide in the reaction solution obtained by the electrode reaction is used. For example, when hydrogen peroxide is produced using an electrode reaction, typically, as the reaction solution (solution containing hydrogen peroxide), an aqueous hydrogen peroxide solution (aqueous solution containing hydrogen peroxide) is obtained. In the reaction step, this aqueous hydrogen peroxide solution can be used as it is or, after performing post-treatment as necessary, as a hydrogen peroxide source.

[0088] The production of hydrogen peroxide using an electrode reaction can be carried out, for example, by the method described in JP-A-2017-39981 (the above-mentioned Patent Document 3) or with reference to its description. For example, a two-chamber device equipped with a cation exchange membrane or the like as a diaphragm is prepared as a device for performing an electrode reaction. As the cathode, one made of a noble metal having a catalytic action such as platinum or a general-purpose metal having a catalytic action such as nickel, cobalt, or stainless steel is used. As the anode, a substrate made of a metal oxide or metal having conductivity such as tin oxide can be used, and preferably, one having an electrode catalyst such as bismuth vanadate (BiVO4) or lanthanum aluminate (LaAlO3) supported on its surface is used. As the electrolytic solution for the cathode and anode, an aqueous solution containing either or both of carbonate ions (CO3 2- ) and hydrogen carbonate ions (HCO3 - ) is used. For this purpose, an aqueous solution in which either or both of a carbonate such as potassium carbonate (K2CO3) and a hydrogen carbonate such as potassium hydrogen carbonate (KHCO3) are dissolved in water may be used. The total concentration of carbonate ions and hydrogen carbonate ions in the electrolytic solution (the total concentration of carbonate and hydrogen carbonate) is preferably 1 M or more, more preferably a high concentration, and particularly preferably a saturated solution of either or both of carbonate and hydrogen carbonate.

[0089] By applying a voltage and passing an electric current for a certain period of time using the above-described apparatus to perform an electrode reaction, hydrogen peroxide is generated. More specifically, an aqueous solution in which the generated hydrogen peroxide is dissolved in the electrolytic solution is obtained as a reaction solution.

[0090] The concentration of hydrogen peroxide in the reaction solution obtained by the electrode reaction used in the reaction step is preferably 10 to 100 mM, and may be, for example, any of 20 to 100 mM, 30 to 100 mM, and 40 to 100 mM. When the concentration of hydrogen peroxide in the reaction solution is at or above the lower limit value, aldehyde can be produced more efficiently. A reaction solution having a hydrogen peroxide concentration of 100 mM or less is more easily obtained by the electrode reaction. The concentration of hydrogen peroxide in the reaction solution obtained by the electrode reaction is lower than the concentration of hydrogen peroxide in hydrogen peroxide solution produced by the anthraquinone method. However, in the production method of the present embodiment, by using the catalyst group, aldehyde can be produced more efficiently than in the conventional case when using a reaction solution obtained by a conventional electrode reaction.

[0091] In the reaction step, the amount of use of the reaction solution (for example, the above hydrogen peroxide solution) obtained by the electrode reaction is preferably 1 to 10 times by mass, more preferably 1 to 1.5 times by mass, relative to the amount of use of alcohol.

[0092] In the reaction step, the amount of hydrogen peroxide used is preferably 1 to 2 times the molar amount, more preferably 1 to 1.7 times the molar amount, and even more preferably 1 to 1.4 times the molar amount relative to the amount of alcohol used. When the amount of hydrogen peroxide used is at least the lower limit value, the reaction rate of alcohol and the production rate of aldehyde become higher. When the amount of hydrogen peroxide used is at most the upper limit value, excessive use of hydrogen peroxide is suppressed.

[0093] <Organic solvent> In the reaction step, it is preferable to use an organic solvent in addition to the solvent in the reaction solution obtained by the electrode reaction. By using the organic solvent, the reaction rate of alcohol and the production rate of aldehyde may increase. For example, by using an organic solvent in which alcohol is soluble, the reaction rate of alcohol and the production rate of aldehyde may be made higher.

[0094] In this specification, "solvent" is a concept that includes both a component that is liquid at normal temperature for dissolving a solute and a component that is liquid at normal temperature and functions as a dispersion medium for dispersing a dispersed substance, unless otherwise specified.

[0095] The organic solvent is not particularly limited as long as it is other than alcohol. Preferred organic solvents include, for example, aromatic hydrocarbons such as toluene, o-xylene, m-xylene, p-xylene; aliphatic hydrocarbons such as hexane; ethers having an ether bond such as 1,4-dioxane, tetrahydrofuran (THF), diethyl ether, dibutyl ether, 1,2-dimethoxyethane, 1,2-diethoxyethane; amides such as 1,3-dimethyl-2-imidazolidinone (DMI), N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), N-methyl-2-pyrrolidone (NMP); nitriles having a cyano group such as acetonitrile, propionitrile, butyronitrile, benzonitrile; Halogenated aliphatic hydrocarbons such as methylene chloride, chloroform, carbon tetrachloride, 1,2-dichloroethane; Halogenated aromatic hydrocarbons such as chlorobenzene, 1,2-dichlorobenzene (o-dichlorobenzene), 1,3-dichlorobenzene (m-dichlorobenzene), 1,4-dichlorobenzene (p-dichlorobenzene), etc. can be mentioned. Among these, more preferable organic solvents include aromatic hydrocarbons.

[0096] The organic solvent used in the reaction step may be only one kind or two or more kinds. When there are two or more kinds, their combinations and ratios can be arbitrarily selected according to the purpose.

[0097] When using an organic solvent, in the said reaction step, the usage amount of the organic solvent is preferably 0.1 to 1000 mass times, more preferably 1 to 100 mass times, relative to the usage amount of alcohol. When the usage amount of the organic solvent is at least the lower limit value, the effect obtained by using the organic solvent becomes higher. When the usage amount of the organic solvent is at most the upper limit value, excessive use of the organic solvent is suppressed.

[0098] <Other component (i)> In the said reaction step, within the range not impairing the effects of the present invention, other components (which may be referred to as "other component (i)" in this specification) that do not correspond to any of alcohol, catalyst group (metal-based non-oxide solid catalyst, metal oxide catalyst), hydrogen peroxide, organic solvent, and components other than hydrogen peroxide in the reaction solution obtained by the electrode reaction may or may not be used.

[0099] The type and usage amount of the said other component (i) can be arbitrarily selected according to the purpose and are not particularly limited.

[0100] The other component (i) used in the reaction step may be only one kind or two or more kinds. When there are two or more kinds, their combinations and ratios can be arbitrarily selected according to the purpose.

[0101] In the reaction step, the ratio ([amount of other component (i) used (parts by mass)] / [total amount of components used (parts by mass)] × 100) of the amount of other component (i) used (parts by mass) to the total amount of components used (parts by mass) is preferably 10% by mass or less, and may be, for example, any one of 5% by mass or less, 3% by mass or less, and 1% by mass or less. When the ratio is at or below the upper limit value, the reaction rate of the alcohol and the production rate of the aldehyde become higher. On the other hand, the ratio is 0% by mass or more. Here, the "total amount of components used (parts by mass)" is the total amount of alcohol, catalyst group (metal-based non-oxide solid catalyst, metal oxide catalyst), reaction solution obtained by the electrode reaction, organic solvent, and other component (i) used. When calculating the ratio, if an organic solvent or other component (i) is not used in the reaction step, the amount used is taken as 0 parts by mass.

[0102] <Other reaction conditions> In the reaction step, the reaction between hydrogen peroxide and alcohol (oxidation reaction of alcohol) may be carried out in an air atmosphere or in an inert gas atmosphere. In terms of higher reaction rate of alcohol and higher production rate of aldehyde, the oxidation reaction of alcohol is preferably carried out in an inert gas atmosphere. Examples of the inert gas include known gases such as nitrogen gas, argon gas, and helium gas.

[0103] In the reaction step, the pH of the reaction solution at the start of the oxidation reaction is not particularly limited, but is preferably 11.0 to 14.0, and may be, for example, either 11.0 to 12.5 or 12.5 to 14.0. When the pH is in such a range, the reaction rate of the alcohol and the production rate of the aldehyde become higher. The pH can be adjusted by adjusting the types and contents of the components used in the reaction step. For example, among the metal oxide catalysts, by using magnesium oxide in particular, the pH can be easily increased.

[0104] In the above reaction step, the reaction temperature during the reaction of hydrogen peroxide and alcohol is not particularly limited, but it is preferably 20°C to 100°C, more preferably 30°C to 90°C, even more preferably 35°C to 85°C. For example, it may be either 50°C to 85°C or 70°C to 85°C. When the reaction temperature is equal to or higher than the lower limit value, the reaction rate of alcohol and the production rate of aldehyde become higher. When the reaction temperature is equal to or lower than the upper limit value, the inhibitory effect on side reactions becomes higher.

[0105] In the above reaction step, the reaction time during the reaction of hydrogen peroxide and alcohol is preferably set in consideration of other reaction conditions such as the usage amount of the catalyst group and the reaction temperature. Usually, the reaction time is preferably 0.5 to 48 hours, more preferably 0.5 to 24 hours. For example, it may be either 0.5 to 12 hours or 0.5 to 5 hours.

[0106] In the above reaction step, the addition order of each component to the target substance is not particularly limited, but hydrogen peroxide is preferably added after the addition of the catalyst group and alcohol. For example, in the reaction step, after mixing the catalyst group and alcohol, it is preferable to further add hydrogen peroxide (more specifically, the reaction solution containing hydrogen peroxide obtained by the electrode reaction) to the obtained mixture. When adding the catalyst group, the metal-based non-oxide solid catalyst and the metal oxide catalyst may be added separately, or a mixture obtained by mixing the metal-based non-oxide solid catalyst and the metal oxide catalyst may be added. When the metal-based non-oxide solid catalyst and the metal oxide catalyst are added separately, their addition order is not particularly limited.

[0107] When using a solvent in the above reaction step, its addition order is not particularly limited, but it is preferably added after the addition of hydrogen peroxide (more specifically, the reaction solution containing hydrogen peroxide obtained by the electrode reaction), and it is preferably added last among all the components.

[0108] When using other component (i) in the reaction step, the addition order is not particularly limited, and it is preferably adjusted as appropriate according to the type of other component (i).

[0109] Both the metal-based non-oxide solid catalyst and the metal oxide catalyst are preferably added as powders such as particles. By doing so, the reaction rate of alcohol and the production rate of aldehyde become higher.

[0110] In the reaction step, neither the metal-based non-oxide solid catalyst nor the metal oxide catalyst dissolves in the oxidation reaction solution. Therefore, after the reaction step, by filtering the oxidation reaction solution, the metal-based non-oxide solid catalyst and the metal oxide catalyst can be separated and removed, and no other special or complicated operations for removing them are required. Furthermore, these catalysts after separation can be easily reused as the catalyst by washing with a solvent such as water or an organic solvent and drying. Drying can be carried out, for example, at a temperature of about 100 to 120 °C for about 6 to 12 hours.

[0111] As described above, in the production method of the present embodiment, the metal-based non-oxide solid catalyst and the metal oxide catalyst can be easily separated without performing special or complicated operations. Therefore, the production method of the present embodiment is suitable for the mass production of aldehydes with a large production scale, and is also suitable for, for example, mass production using flow synthesis.

[0112] In the production method of the present embodiment, after the reaction step, before or after removing the metal-based non-oxide solid catalyst and the metal oxide catalyst, post-treatment can be performed on the oxidation reaction solution as needed by a known method to extract the aldehyde. That is, before or after removing the catalyst, post-treatment operations such as filtration, washing, extraction, pH adjustment, dehydration, and concentration can be performed either alone or in combination of two or more as appropriate according to need, and the aldehyde can be extracted by concentration, crystallization, reprecipitation, distillation, sublimation, column chromatography, etc. Further, the extracted aldehyde can be purified by performing any one of the operations such as crystallization, reprecipitation, distillation, sublimation, column chromatography, extraction, and stirring and washing of crystals with a solvent, or a combination of two or more, one or more times as needed. Alternatively, after the reaction step, before or after removing the catalyst, after performing post-treatment on the oxidation reaction solution as needed, it may be used for the intended purpose without extracting the aldehyde. For example, the oxidation reaction solution may be used for the next intended reaction without extracting the aldehyde.

[0113] The aldehyde obtained by the production method of the present embodiment has the following general formula (2)

[0114] [Chemical formula] (In the formula, R is an aliphatic hydrocarbon group having 1 to 10 carbon atoms or an aromatic ring-containing hydrocarbon group, and one or more hydrogen atoms in the aliphatic hydrocarbon group and the aromatic ring-containing hydrocarbon group may be substituted with fluorine atoms.) It is preferably a compound represented by. In the reaction step, the production rate of such an aldehyde becomes higher.

[0115] The aldehyde represented by the general formula (2) is produced from the alcohol represented by the general formula (1). That is, R in the general formula (2) is the same as R in the general formula (1). And the preferable R in the general formula (2) is the same as the preferable R in the general formula (1). Therefore, further detailed description of the aldehyde represented by the general formula (2) is omitted.

[0116] The structure of the aldehyde obtained by the production method of the present embodiment can be confirmed by known methods such as nuclear magnetic resonance (NMR) spectroscopy, mass spectrometry (MS), infrared spectroscopy (IR), etc.

[0117] The aldehyde obtained by the production method of the present embodiment can be used as a functional chemical such as an intermediate raw material for pharmaceuticals, agricultural chemicals, fragrances, and various organic chemicals.

[0118] <<Catalyst Composition>> The catalyst composition according to an embodiment of the present invention is a catalyst composition for obtaining an aldehyde by reacting hydrogen peroxide and an alcohol, and the catalyst composition includes one or more selected from the group consisting of a platinum-based non-oxide solid catalyst, a ruthenium-based non-oxide solid catalyst, a palladium-based non-oxide solid catalyst, and an iridium-based non-oxide solid catalyst, and a metal oxide catalyst. The catalyst composition of the present embodiment is typically a composition of a solid catalyst in a solid state at normal temperature, reflecting the properties of the metal-based non-oxide solid catalyst, which is the main component thereof, and the metal oxide catalyst.

[0119] In the production method according to the above-described embodiment of the present invention, by using the catalyst composition of the present embodiment, an aldehyde can be produced favorably. The catalyst group, which is a mixture obtained by mixing a metal-based non-oxide solid catalyst and a metal oxide catalyst used in the production method, is the catalyst composition of the present embodiment.

[0120] The solid catalyst of the metal-based non-oxide and the metal oxide catalyst contained in the catalyst composition of the present embodiment are the same as the solid catalyst of the metal-based non-oxide and the metal oxide catalyst in the catalyst group used in the manufacturing method, respectively. And the solid catalyst of the metal-based non-oxide and the metal oxide catalyst contained in the catalyst composition of the present embodiment exhibit the same effects as the solid catalyst of the metal-based non-oxide and the metal oxide catalyst in the catalyst group used in the manufacturing method during the oxidation reaction of alcohol. Therefore, detailed descriptions of the solid catalyst of the metal-based non-oxide and the metal oxide catalyst contained in the catalyst composition are omitted.

[0121] For the same reason as in the case of the catalyst group, in the catalyst composition, the solid catalyst of the metal-based non-oxide is preferably a solid catalyst of the platinum-based non-oxide, and more preferably platinum black.

[0122] That is, the catalyst composition preferably contains at least a solid catalyst of the platinum-based non-oxide as the solid catalyst of the metal-based non-oxide. The higher the content of the solid catalyst of the platinum-based non-oxide, the more preferable it is, and it is preferable that the solid catalyst of the platinum-based non-oxide is platinum black. More specifically, in the catalyst composition, the ratio of the content of the solid catalyst of the platinum-based non-oxide to the total content of the solid catalysts of the metal-based non-oxides ([content of the solid catalyst of the platinum-based non-oxide in the catalyst composition (parts by mass)] / ([content of the solid catalyst of the platinum-based non-oxide in the catalyst composition (parts by mass)] + [content of the solid catalyst of the ruthenium-based non-oxide in the catalyst composition (parts by mass)] + [content of the solid catalyst of the palladium-based non-oxide in the catalyst composition (parts by mass)] + [content of the solid catalyst of the iridium-based non-oxide in the catalyst composition (parts by mass)]) × 100) is preferably 50% by mass or more, more preferably 70% by mass or more, still more preferably 80% by mass or more, and may be any of, for example, 90% by mass or more, 95% by mass or more, and 97% by mass or more. On the other hand, the ratio is 100% by mass or less.

[0123] In the catalyst composition, the ratio of the content of platinum black to the content of the platinum-based non-oxide solid catalyst ([content of platinum black in the catalyst composition (parts by mass)] / [content of the platinum-based non-oxide solid catalyst in the catalyst composition (parts by mass)] × 100) is preferably 50% by mass or more, more preferably 70% by mass or more, still more preferably 80% by mass or more, and may be, for example, any one of 90% by mass or more, 95% by mass or more, and 97% by mass or more. On the other hand, the ratio is 100% by mass or less.

[0124] The metal oxide catalyst contained in the catalyst composition may be only one kind or two or more kinds. When there are two or more kinds, their combinations and ratios can be arbitrarily selected according to the purpose.

[0125] For the same reason as in the case of the catalyst group, in the catalyst composition, the metal oxide catalyst is preferably one kind or two or more kinds selected from the group consisting of magnesium oxide, silicon dioxide, titanium dioxide, aluminum oxide, cerium(IV) oxide, and zirconium oxide.

[0126] In the catalyst composition, the ratio of the total content of magnesium oxide, silicon dioxide, titanium dioxide, aluminum oxide, cerium(IV) oxide, and zirconium oxide to the total content of the metal oxide catalyst (([content of magnesium oxide in the catalyst composition (parts by mass)] + [content of silicon dioxide in the catalyst composition (parts by mass)] + [content of titanium dioxide in the catalyst composition (parts by mass)] + [content of aluminum oxide in the catalyst composition (parts by mass)] + [content of cerium(IV) oxide in the catalyst composition (parts by mass)] + [content of zirconium oxide in the catalyst composition (parts by mass)]) / [total content of the metal oxide catalyst in the catalyst composition (parts by mass)] × 100) is preferably 50% by mass or more, more preferably 70% by mass or more, still more preferably 80% by mass or more, and may be, for example, any one of 90% by mass or more, 95% by mass or more, and 97% by mass or more. When the ratio is at least the lower limit value, the reaction rate of alcohol and the production rate of aldehyde become higher. On the other hand, the ratio is 100% by mass or less.

[0127] For the same reason as in the case of the catalyst group, in the catalyst composition, the mass ratio of [content of solid catalyst of metal-based non-oxide]:[content of metal oxide catalyst] is preferably 1:1 to 1:21, more preferably 1:2 to 1:12, even more preferably 1:2 to 1:8, and particularly preferably 1:2 to 1:6.

[0128] The catalyst composition of the present embodiment may or may not contain other components (which may be referred to as "other components (ii)" in this specification) that do not fall under either the solid catalyst of metal-based non-oxide or the metal oxide catalyst.

[0129] The type and content of the other components (ii) can be arbitrarily selected according to the purpose and are not particularly limited.

[0130] The other components (ii) contained in the catalyst composition may be only one type or two or more types. When there are two or more types, their combinations and ratios can be arbitrarily selected according to the purpose.

[0131] In the catalyst composition, the ratio ([content of other components (ii) of catalyst composition (parts by mass)] / [total mass of catalyst composition (parts by mass)] × 100) of the content (parts by mass) of other components (ii) to the total mass (parts by mass) of the catalyst composition is preferably 10% by mass or less, and may be, for example, any one of 5% by mass or less, 3% by mass or less, and 1% by mass or less. When the ratio is below the upper limit value, the reaction rate of alcohol and the production rate of aldehyde become higher. On the other hand, the ratio is 0% by mass or more.

[0132] The catalyst composition can be produced by blending a metal-based non-oxide solid catalyst, a metal oxide catalyst, and, if necessary, other component (ii). The blending amounts of these components may be adjusted so that the contents of these components in the catalyst composition become the target values. The blending method of these components (the metal-based non-oxide solid catalyst, the metal oxide catalyst, and, if necessary, other component (ii)) is not particularly limited as long as these components are finally mixed.

[0133] The method of using the catalyst composition during the production of aldehyde is as described in the method for producing aldehyde according to one embodiment of the present invention described above.

Examples

[0134] Hereinafter, the present invention will be described in more detail with reference to specific examples. However, the present invention is not limited to the examples shown below.

[0135] <<Production of Hydrogen Peroxide>> [Production Example 1] A two-chamber device equipped with a Nafion membrane, which is a cation exchange membrane, as a diaphragm was prepared as a device for performing an electrode reaction. A platinum electrode was used as the cathode, and a conductive electrode substrate made of tin oxide (0.8 cm 2 ) was used as it was. An aqueous solution containing potassium carbonate and potassium hydrogen carbonate, in which the concentration of potassium carbonate was 3.5 M and the concentration of potassium hydrogen carbonate was 5 M, was injected into each of the cathode and anode chambers in an amount of 35 mL each. A voltage was applied to the above device using a potentiostat, and an electrode reaction was performed by passing 1280 coulombs of electricity at a constant current of 50 mA, and an aqueous hydrogen peroxide solution having a hydrogen peroxide concentration of 63.3 mM was obtained as a reaction solution. The concentration of this hydrogen peroxide was determined from the measurement data of the color development amount when Fe 2+ was oxidized to Fe 3+ . This is the same for the aqueous hydrogen peroxide solutions used in other examples and comparative examples described later.

[0136] <<Production of Aldehyde>> <Production of (4-Trifluoromethyl)benzaldehyde> [Example 1] Into a eggplant-shaped flask (30 mL), platinum black (manufactured by N.E. Chemcat Corporation, 60 mg), magnesium oxide (MgO, manufactured by Fujifilm Wako Pure Chemical Corporation, 300 mg), (4-trifluoromethyl)benzyl alcohol (manufactured by Tokyo Chemical Industry Co., Ltd., 94.41 mg (0.536 mmol)), and the hydrogen peroxide aqueous solution with a concentration of 63.3 mM obtained in Production Example 1 (10 mL, 0.633 mmol as hydrogen peroxide) were placed. After further adding toluene (10 mL), a Dimroth condenser was installed in this eggplant-shaped flask. The obtained mixture was stirred at 80 °C for 2.5 hours to conduct the reaction. From the obtained oxidation reaction solution, the product was isolated by silica gel column chromatography (developing solution: hexane / ethyl acetate = 9 / 1) to obtain (4-trifluoromethyl)benzaldehyde (yield 60%, amount 56.3 mg (0.323 mmol)).

[0137] That the obtained product was (4-trifluoromethyl)benzaldehyde was 1 confirmed by 1H NMR and 13 13C NMR. Among the analytical data obtained at this time, 1 the spectral data of 1H NMR (400 MHz, CDCl3, 25 °C) is shown in Figure 1, 13 and the spectral data of 13C NMR (100 MHz, CDCl3, 25 °C) is shown in Figure 2, respectively. Note that the peaks observed at 0 to 4.3 ppm in Figure 1 are peaks of impurities and are irrelevant to the target product.

[0138]

Chemical formula

[0139] [Example 2] A test tube with an inner diameter of 10 mm was charged with platinum black (manufactured by N.E. Chemcat Corporation, 12 mg), magnesium oxide (manufactured by Fujifilm Wako Pure Chemical Corporation, 60 mg), (4-trifluoromethyl)benzyl alcohol (manufactured by Tokyo Chemical Industry Co., Ltd., 19.38 mg (0.11 mmol)), and an aqueous hydrogen peroxide solution with a concentration of 55 mM (2 mL, 0.11 mmol as hydrogen peroxide) obtained by the same method as in Production Example 1. After adding toluene (1 mL), the resulting mixture was stirred at 80°C for 2 hours to conduct the reaction. The amounts of these raw materials used are shown in Table 1. To the obtained oxidation reaction solution, biphenyl (manufactured by Wako Pure Chemical Industries, Ltd., 15.4 mg (0.1 mmol)) was added as an internal standard, and the result of analysis by gas chromatography showed that the conversion rate of (4-trifluoromethyl)benzyl alcohol was 83%, the yield of (4-trifluoromethyl)benzaldehyde was 66%, and the selectivity of (4-trifluoromethyl)benzaldehyde was 80%. These results are shown in Table 2. In Table 2, "pH of the oxidation reaction solution" refers to the pH of the reaction solution at the start of the oxidation reaction.

[0140] The conversion rate of the above raw materials and the selectivity of the target product were calculated by the following formula using the analysis data by gas chromatography. [Conversion rate of raw material (%)] = (1 - [Residual amount of raw material (mol)] / [Amount of raw material used (mol)]) × 100 [Selectivity of target product (%)] = [Yield of target product (%)] / [Conversion rate of raw material (%)] × 100

[0141] That the obtained product was (4-trifluoromethyl)benzaldehyde was confirmed by analyzing the product in the same manner as in Example 1. At this time, the same analysis data as in the case of Example 1 were obtained.

[0142] [Examples 3 to 7] As shown in Table 1, (4-trifluoromethyl)benzaldehyde was produced in the same manner as in Example 2, except that silicon dioxide (SiO2, Example 3), titanium dioxide (TiO2, Example 4), aluminum oxide (Al2O3, Example 5), cerium(IV) oxide (CeO2, Example 6), or zirconium oxide (ZrO2, Example 7) in the same amount (mg) as the magnesium oxide was used instead of the magnesium oxide. The results are shown in Table 2.

[0143] [Comparative Example 1] As shown in Table 1, (4-trifluoromethyl)benzaldehyde was produced in the same manner as in Example 2, except that magnesium oxide was not used. The results are shown in Table 2.

[0144] In Examples 3 to 7 and Comparative Example 1, it was confirmed that the obtained product was (4-trifluoromethyl)benzaldehyde by analyzing the product in the same manner as in Example 1. At this time, the same analysis data as in Example 1 were obtained.

[0145]

Table 1

[0146]

Table 2

[0147] As is clear from the above results, in Examples 2 to 7, even when the type of the metal oxide catalyst was changed, (4-trifluoromethyl)benzaldehyde was obtained in a good yield of 49% or more (49 to 66%). On the other hand, in Comparative Example 1 where no metal oxide catalyst was used, the yield of (4-trifluoromethyl)benzaldehyde was 41%, which was the lowest.

[0148] [Examples 8 to 12] As shown in Table 3, (4-trifluoromethyl)benzaldehyde was produced in the same manner as in Example 2, except that the amount of use of either one or both of platinum black and magnesium oxide was changed. The results are shown in Table 4.

[0149] [Comparative Example 2] As shown in Table 3, (4-trifluoromethyl)benzaldehyde was produced in the same manner as in Example 8, except that magnesium oxide was not used. The results are shown in Table 4.

[0150] [Comparative Example 3] As shown in Table 3, (4-trifluoromethyl)benzaldehyde was produced in the same manner as in Example 11, except that magnesium oxide was not used. The results are shown in Table 4.

[0151] [Comparative Example 4] As shown in Table 3, an attempt was made to produce (4-trifluoromethyl)benzaldehyde in the same manner as in Example 11, except that platinum black was not used. The results are shown in Table 4.

[0152] In Examples 8 to 12 and Comparative Examples 2 to 4, that the obtained product was (4-trifluoromethyl)benzaldehyde was confirmed by analyzing the product in the same manner as in Example 1. At this time, the same analysis data as in the case of Example 1 were obtained.

[0153] Tables 3 to 4 also include descriptions of Example 2 and Comparative Example 1.

[0154]

Table 3

[0155]

Table 4

[0156] As is clear from the above results, in Examples 8 to 9, when the amount of the metal oxide catalyst used was changed, (4-trifluoromethyl)benzaldehyde was obtained in a yield of 34% or more (34 to 44%). On the other hand, in Comparative Example 2 where no metal oxide catalyst was used, the yield of (4-trifluoromethyl)benzaldehyde was 32%, which was the lowest.

[0157] Also in Examples 2 and 10, when the amount of the metal oxide catalyst used was changed, (4-trifluoromethyl)benzaldehyde was obtained in a yield of 50% or more (50 to 66%). On the other hand, in Comparative Example 1 where no metal oxide catalyst was used, the yield of (4-trifluoromethyl)benzaldehyde was 41%, which was the lowest.

[0158] Also in Examples 11 and 12, when the amount of the metal oxide catalyst used was changed, (4-trifluoromethyl)benzaldehyde was obtained in a yield of 61% or more (61 to 62%). On the other hand, in Comparative Example 3 where no metal oxide catalyst was used, the yield of (4-trifluoromethyl)benzaldehyde was 37%, which was the lowest.

[0159] In Comparative Example 4 where platinum black was not used, the amount of the metal oxide catalyst used was the same, and unlike in Examples 2, 8, and 11 where platinum black was used, (4-trifluoromethyl)benzaldehyde could not be obtained.

[0160] <Production of Benzaldehyde> [Example 13] As shown in Table 5, benzaldehyde was produced in the same manner as in Example 2, except that benzyl alcohol in the same amount (mmol) as this (4-trifluoromethyl)benzyl alcohol was used instead of (4-trifluoromethyl)benzyl alcohol. The results are shown in Table 6. That what was obtained was benzaldehyde was 1 confirmed by 1H NMR and 13It was confirmed by \(^{13}\)C NMR. Among the analytical data obtained at this time, 1 the spectral data of \(^1\)H NMR (400 MHz, CDCl\(_3\), 25 °C) are shown in Figure 3, 13 and the spectral data of \(^{13}\)C NMR (100 MHz, CDCl\(_3\), 25 °C) are shown in Figure 4, respectively.

[0161] [Chemical formula]

[0162] [Comparative Example 5] As shown in Table 5, benzaldehyde was produced in the same manner as in Example 13, except that magnesium oxide was not used. The results are shown in Table 6. That the product obtained was benzaldehyde was confirmed by analyzing the product in the same manner as in Example 13. At this time, the same analytical data as in Example 13 were obtained.

[0163] [Production of 2-octen-1-al] [Example 14] As shown in Table 5, 2-octen-1-al (alias: 2-octenal) was produced in the same manner as in Example 2, except that 2-octen-1-ol in the same amount (mmol) as this (4-trifluoromethyl)benzyl alcohol was used instead of (4-trifluoromethyl)benzyl alcohol. The results are shown in Table 6. That the product obtained was 2-octen-1-al was 1 confirmed by \(^1\)H NMR and 13 \(^{13}\)C NMR. Among the analytical data obtained at this time, 1 the spectral data of \(^1\)H NMR (400 MHz, CDCl\(_3\), 25 °C) are shown in Figure 5, 13 and the spectral data of \(^{13}\)C NMR (100 MHz, CDCl\(_3\), 25 °C) are shown in Figure 6, respectively.

[0164] [Chemical formula]

[0165] [Comparative Example 6] As shown in Table 5, 2-octen-1-al was produced in the same manner as in Example 14, except that magnesium oxide was not used. The results are shown in Table 6. That the obtained product was 2-octen-1-al was confirmed by analyzing the product in the same manner as in Example 14. At this time, the same analysis data as in the case of Example 14 were obtained.

[0166] [Production of Geranial] [Example 15] As shown in Table 5, geranial (also known as (E)-3,7-dimethylocta-2,6-dienal) was produced in the same manner as in Example 2, except that geraniol (also known as 3,7-dimethyl-2,6-octadien-1-ol) in the same amount (mmol) as this (4-trifluoromethyl)benzyl alcohol was used instead of (4-trifluoromethyl)benzyl alcohol. The results are shown in Table 6. That the obtained product was geranial was 1 confirmed by 1H NMR and 13 13C NMR. Among the analysis data obtained at this time, 1 the spectral data of 1H NMR (400 MHz, CDCl3, 25 °C) are shown in Fig. 7, 13 and the spectral data of 13C NMR (100 MHz, CDCl3, 25 °C) are shown in Fig. 8, respectively.

[0167] [Chemical Formula]

[0168] [Comparative Example 7] As shown in Table 5, geranial was produced in the same manner as in Example 15, except that magnesium oxide was not used. The results are shown in Table 6. That the product obtained was geraniol was confirmed by analyzing the product in the same manner as in Example 15. At this time, analysis data similar to that in Example 15 was obtained.

[0169] <Production of 3-Fluorobenzaldehyde> [Example 16] As shown in Table 5, 3-fluorobenzaldehyde was produced in the same manner as in Example 2, except that the same amount (mmol) of 3-fluorobenzyl alcohol as this (4-trifluoromethyl)benzyl alcohol was used instead of (4-trifluoromethyl)benzyl alcohol. The results are shown in Table 6. That the product obtained was 3-fluorobenzaldehyde 1 was confirmed by 1H NMR and 13 13C NMR. Among the analysis data obtained at this time, 1 the spectral data of 1H NMR (400 MHz, CDCl3, 25 °C) is shown in Fig. 9, 13 and the spectral data of 13C NMR (100 MHz, CDCl3, 25 °C) is shown in Fig. 10, respectively.

[0170]

Chemical formula

[0171] [Comparative Example 8] As shown in Table 5, 3-fluorobenzaldehyde was produced in the same manner as in Example 16, except that magnesium oxide was not used. The results are shown in Table 6. That the product obtained was 3-fluorobenzaldehyde was confirmed by analyzing the product in the same manner as in Example 16. At this time, analysis data similar to that in Example 16 was obtained.

[0172] <Production of 4-Fluorobenzaldehyde> [Example 17] As shown in Table 5, 3,4-difluorobenzaldehyde was produced in the same manner as in Example 2, except that 4-fluorobenzyl alcohol in the same amount (mmol) as this (4-trifluoromethyl)benzyl alcohol was used instead of (4-trifluoromethyl)benzyl alcohol. The results are shown in Table 6. That the obtained product was 4-fluorobenzaldehyde was 1 confirmed by 1H NMR and 13 13C NMR. Among the analytical data obtained at this time, 1 the spectral data of 1H NMR (400 MHz, CDCl3, 25 °C) are shown in Fig. 11, 13 and the spectral data of 13C NMR (100 MHz, CDCl3, 25 °C) are shown in Fig. 12, respectively.

[0173] [Chemical formula]

[0174] [Comparative Example 9] As shown in Table 5, 4-fluorobenzaldehyde was produced in the same manner as in Example 17, except that magnesium oxide was not used. The results are shown in Table 6. That the obtained product was 4-fluorobenzaldehyde was confirmed by analyzing the product in the same manner as in Example 17. At this time, the same analytical data as in the case of Example 17 were obtained.

[0175] [Production of 3,4-difluorobenzaldehyde] [Example 18] As shown in Table 5, 3,4-difluorobenzaldehyde was produced in the same manner as in Example 2, except that 3,4-difluorobenzyl alcohol in the same amount (mmol) as this (4-trifluoromethyl)benzyl alcohol was used instead of (4-trifluoromethyl)benzyl alcohol. The results are shown in Table 6. That the obtained product was 3,4-difluorobenzaldehyde was 1 confirmed by 1H NMR and 13It was confirmed by 13C NMR. Among the analysis data obtained at this time, 1 The spectral data of 1H NMR (400 MHz, CDCl3, 25 °C) are shown in Fig. 13, 13 and the spectral data of 13C NMR (100 MHz, CDCl3, 25 °C) are shown in Fig. 14, respectively.

[0176] [Chemical formula]

[0177] [Comparative Example 10] As shown in Table 5, 3,4-difluorobenzaldehyde was produced in the same manner as in Example 18, except that magnesium oxide was not used. The results are shown in Table 6. That the product obtained was 3,4-difluorobenzaldehyde was confirmed by analyzing the product in the same manner as in Example 18. At this time, the same analysis data as in the case of Example 18 were obtained.

[0178] [Table 5]

[0179] [Table 6]

[0180] As is clear from the above results, in Examples 13 to 18, even when the type of alcohol was changed, the corresponding aldehyde was obtained in a good yield of 32% or more (32 to 67%). On the other hand, in Comparative Examples 5 to 10 where no metal oxide catalyst was used, the aldehyde yields were all lower compared to the cases of the Examples where the same type of alcohol was used.

[0181] [Production of (4-trifluoromethyl)benzaldehyde] [Examples 19 to 22] As shown in Table 7, (4-trifluoromethyl)benzaldehyde was produced in the same manner as in Example 2, except that one of the reaction temperature and reaction time was changed when hydrogen peroxide and alcohol were reacted in the presence of a catalyst group. The results are shown in Table 7. That the obtained product was (4-trifluoromethyl)benzaldehyde was confirmed by analyzing the product in the same manner as in Example 2. At this time, the same analysis data as in Example 2 were obtained.

[0182]

Table 7

[0183] As is clear from the above results, in Examples 2 and 19 to 22, (4-trifluoromethyl)benzaldehyde was obtained in a good yield of 40% or more (40 to 66%) in the range of a reaction temperature of 40 to 80°C and a reaction time of 1 to 4 hours.

[0184] <Production of (4-trifluoromethyl)benzaldehyde> [Comparative Example 11] Production of (4-trifluoromethyl)benzaldehyde was attempted in the same manner as in Example 2, except that platinum(IV) oxide (PtO2) in the same amount (mg) as this platinum black was used instead of platinum black. As a result, the oxidation reaction of (4-trifluoromethyl)benzyl alcohol did not proceed, and no (4-trifluoromethyl)benzaldehyde was obtained at all.

Industrial Applicability

[0185] The present invention can be used for the production of aldehydes using hydrogen peroxide produced by a method utilizing an electrode reaction and an alcohol.

Claims

1. A method for producing an aldehyde, comprising a reaction step of reacting hydrogen peroxide and an alcohol in the presence of a catalyst group to obtain an aldehyde, wherein the hydrogen peroxide is hydrogen peroxide in a reaction solution obtained by an electrode reaction, as the catalyst group, one or more metal-based non-oxide solid catalysts selected from the group consisting of a platinum-based non-oxide solid catalyst, a ruthenium-based non-oxide solid catalyst, a palladium-based non-oxide solid catalyst, and an iridium-based non-oxide solid catalyst, and a metal oxide catalyst are used. A method for producing an aldehyde.

2. The method for producing an aldehyde according to claim 1, wherein the metal-based non-oxide solid catalyst is platinum black.

3. The method for producing an aldehyde according to claim 1 or 2, wherein the metal oxide catalyst is one or more selected from the group consisting of magnesium oxide, silicon dioxide, titanium dioxide, aluminum oxide, cerium (IV) oxide, and zirconium oxide.

4. The method for producing an aldehyde according to claim 1 or 2, wherein in the reaction step, the reaction temperature during the reaction of the hydrogen peroxide and the alcohol is 20°C to 100°C.

5. The method for producing an aldehyde according to claim 1 or 2, wherein the concentration of hydrogen peroxide in the reaction solution obtained by the electrode reaction is 10 to 100 mM.

6. The method for producing an aldehyde according to claim 1 or 2, wherein in the reaction step, the mass ratio of [the amount of the metal-based non-oxide solid catalyst used]: [the amount of the metal oxide catalyst used] is 1:1 to 1:

21.

7. The alcohol is represented by the following general formula (1): 【Chemical 1】 (In the formula, R is an aliphatic hydrocarbon group having 1 to 10 carbon atoms or an aromatic ring-containing hydrocarbon group, and one or more hydrogen atoms in the aliphatic hydrocarbon group and the aromatic ring-containing hydrocarbon group may be substituted with fluorine atoms.) The method for producing an aldehyde according to claim 1 or 2, which is a compound represented by

8. The aldehyde is represented by the following general formula (2): 【Chemical 2】 (In the formula, R is an aliphatic hydrocarbon group having 1 to 10 carbon atoms or an aromatic ring-containing hydrocarbon group, and one or more hydrogen atoms in the aliphatic hydrocarbon group and the aromatic ring-containing hydrocarbon group may be substituted with fluorine atoms.) The method for producing an aldehyde according to claim 1 or 2, which is a compound represented by

9. A catalyst composition for obtaining an aldehyde by reacting hydrogen peroxide with an alcohol, The catalyst composition contains one or more metal-based non-oxide solid catalysts selected from the group consisting of a platinum-based non-oxide solid catalyst, a ruthenium-based non-oxide solid catalyst, a palladium-based non-oxide solid catalyst, and an iridium-based non-oxide solid catalyst, and a metal oxide catalyst.

10. The catalyst composition according to claim 9, wherein the metal oxide catalyst is one or more selected from the group consisting of magnesium oxide, silicon dioxide, titanium dioxide, aluminum oxide, cerium (IV) oxide, and zirconium dioxide.

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