JP6339763B2 - Catalyst for dehydrogenation, carbonyl compound using the catalyst, and method for producing hydrogen - Google Patents

Description

  The present invention relates to a catalyst for dehydrogenation reaction containing an organometallic complex having a nitrogen-containing ligand. The present invention also relates to a dehydrogenation method using the organometallic complex as a catalyst, a method for producing a carbonyl compound by dehydrogenation of alcohols, and a method for producing hydrogen by dehydrogenation of alcohol, formic acid or formate. It is. The present invention further relates to a novel organometallic complex having a nitrogen-containing ligand.

  The dehydrogenation reaction of a hydrogen-containing organic compound is one of the most important reactions in organic synthesis and is an industrially valuable reaction. For example, conversion reaction to carbonyl compounds such as aldehydes, ketones, carboxylic acids by dehydrogenation reaction (oxidation reaction) of alcohol is an organic compound used in many fields such as pharmaceuticals, agricultural chemicals, foods, fragrances, materials, or raw materials thereof. Plays an important role in the manufacture of. In addition, a method for producing hydrogen by dehydrogenation of alcohol, formic acid, or formate is a technology that has attracted attention as a hydrogen supply and storage technology for fuel cells.

  Synthesis of carbonyl compounds by oxidative dehydrogenation of alcohol is one of the most important functional group transformations in organic synthesis to obtain intermediates such as pharmaceuticals, agricultural chemicals, and fragrances. Agents and oxidation reactions have been developed. For example, oxidation methods using heavy metal oxidizing agents (potassium permanganate, dichromic acid and its salts, chromium trioxide, etc.) and DMSO oxidation methods (Swern oxidation, etc.) are known as stoichiometric oxidation reagents. . These oxidizing agents and oxidation methods are difficult to implement industrially from the viewpoint of safety and environmental harmony, such as by-product of a large amount of highly toxic waste and generation of bad odor.

  On the other hand, from the viewpoint of environmentally friendly green chemistry, a catalytic oxidation reaction of alcohol using a co-oxidant such as hydrogen peroxide, acetone, molecular oxygen has been developed. However, the reaction using a co-oxidant has problems such as complicated reaction depending on the type of co-oxidant and limited applicable substrates, and from the viewpoint of designing a catalytic reaction based on atomic efficiency. There is still room for improvement.

  From these facts, development of catalytic oxidation reaction of alcohol without using a co-oxidant, that is, catalytic oxidative dehydrogenation reaction is extremely important from the viewpoint of process chemistry. In recent years, such reactions have been reported one after another. For example, oxidative dehydrogenation reactions using ruthenium catalysts (Non-Patent Documents 1 to 5) and iridium catalysts (Non-Patent Documents 6 and 7) have been reported. . However, these reactions are carried out at a relatively high temperature, cannot be applied to base-labile substrates in reactions that require basic conditions, and have a relatively large amount of catalyst. Then there is a problem.

Non-Patent Document 8 reports a dehydrogenative oxidation reaction of an alcohol using a cationic iridium complex, but the reaction is carried out in an aqueous solvent under reflux conditions, taking safety and economy into consideration. Then, it is desirable that it can be carried out at a lower temperature. In addition, in this reaction, the cationic iridium complex itself exhibits acidity, so that it is not suitable for the reaction of a substrate that is easily decomposed in an acidic state. Furthermore, Non-Patent Document 9 reports a catalytic dehydrogenation reaction of a cyclic amine (2,6-dimethyldecahydro-1,5-naphthyridine) using a neutral iridium complex. No application to dehydrogenation reactions has been made.
From the above, it has been desired to develop a catalytic dehydrogenation reaction of alcohol that can be carried out at a relatively low temperature with a low catalyst amount.

In addition, an aldehyde is generated by the oxidation reaction of the primary alcohol, and the corresponding carboxylic acid is obtained by further oxidizing the aldehyde. The reaction in which this proceeds in one pot is extremely important from the viewpoint of process chemistry. . Known stoichiometric oxidizers for this purpose are potassium permanganate (KMnO ₄ ), Jones reagent, pyridinium dichromate (PDC), but heavy metal use and high toxicity compounds It is difficult to industrially implement these methods in terms of economy and safety such as by-products.

As a catalytic method, an oxidation method using ruthenium tetroxide and TEMPO (Non-patent Document 10) is known, but it is difficult to apply to a compound containing many functional groups because the conditions are relatively strong. Moreover, since it is necessary to use a co-oxidant, there is still room for improvement from the viewpoint of designing a catalytic reaction based on atomic efficiency. The method using sodium tungstate (Non-patent Document 11) as a catalyst is a reaction involving danger because a high-concentration hydrogen peroxide solution is used. 1-Me-AZADO oxidation (patent document 1) was also developed, which improved the defects of TEMPO oxidation, but this method also requires the use of a large amount of co-oxidant, so the development of a catalyst that can reduce the environmental burden is hoped for. It was rare.
In view of the above, it has been desired to develop an oxidative dehydrogenation reaction from primary alcohols to carboxylic acids via aldehydes, which proceeds in a low catalytic amount without using a co-oxidant.

On the other hand, hydrogen (H ₂ ) has been conventionally used in various industrial fields as a petroleum refining and chemical raw material, and has recently attracted attention as a fuel for fuel cells. However, since hydrogen is a gas at room temperature and has high reactivity and easily ignites in the air, stable supply or storage of hydrogen is an important issue in the development of fuel cells. For example, as a method for storing hydrogen, a method for storing as compressed gas, a method for storing hydrogen gas in the form of liquid hydrogen, and a method for storing hydrogen by taking it into a hydrogen storage alloy are known. However, these methods have problems in terms of cost, safety, and handling in addition to a small hydrogen storage amount per unit weight of the storage medium.

In order to solve these problems, a method of storing hydrogen in the form of another substance instead of H ₂ is conceivable. For example, formic acid (HCO ₂ H) is known to generate hydrogen (H ₂ ) and carbon dioxide (CO ₂ ) when heated strongly. By utilizing this, hydrogen can be stored stably in the form of formic acid, which is a safe substance, and hydrogen can be generated by appropriately heating formic acid to generate hydrogen. However, since the thermal decomposition reaction of formic acid needs to be carried out at a high temperature, development of a catalyst capable of generating hydrogen from formic acid with high efficiency under milder conditions is desired.

So far, examples using metal complexes as formic acid decomposition catalysts have been reported. For example, Patent Document 2 reports a binuclear metal complex containing iridium and ruthenium. However, since two kinds of transition metals are used, the production cost increases. Patent Document 3 reports a formic acid decomposition reaction using a rhodium complex, but the rhodium complexes in the examples are limited to cationic aco complexes having a bipyridyl-based ligand. Since the amount of catalyst used is about 1 mol%, it cannot be said that the efficiency is necessarily good.
From the above, it has been desired to develop a catalyst for decomposition reaction of formic acid or formate having a low reactivity and high reactivity under mild conditions.

JP 2009-114143 A Japanese Patent No. 4572393 JP 2009-78200 A

J. Ho Choi, N. Kim, Y. J. Shin, J. H. Park and J. Park, Tetrahedron Lett., 2004, 45, 4607-4610. H. Junge and M. Beller, Tetrahedron Lett., 2005, 46, 1031-1034. J. Zhang, G. Leitus, Y. Ben-David and D. Milstein, J. Am. Chem. Soc., 2005, 127, 10840-10841. J. van Buijtenen, J. Meuldijk et al., Organometallics, 2006, 25, 873-881. H. Junge, B. Loges, and M. Beller, Chem. Commun., 2007, 522-524. K. Fujita, N. Tanino and R. Yamaguchi, Org. Lett., 2007, 9 (1), 109-111. K. Fujita, T. Yoshida, Y. Imori and R. Yamaguchi, Org. Lett., 2011, 13 (9), 2278-2281.

Kyoko Kawahara, Kenichi Fujita, Ryohei Yamaguchi “Dehydrogenative Oxidation of Alcohol in Aqueous Solvent Using Novel Water-soluble Cp * Iridium Complex Catalyst”, The 91st Annual Meeting of the Chemical Society of Japan Society, issued on March 11, 2011, lecture number 4C5-48 Yui Tanaka, Kenichi Fujita, Ryohei Yamaguchi “Synthesis of novel Cp * iridium complexes with functional bipyridine ligands and catalytic dehydrogenation of nitrogen-containing heterocycles”, Proceedings of the 91st Annual Meeting of the Chemical Society of Japan , The Chemical Society of Japan, published on March 11, 2011, lecture number 4C5-47 Anelli. P. L, Biffi. C, Montanari. F and Quici. S, J. Org. Chem., 1987, 52, 2559-2562. R. Noyori, M. Aoki and K. Sato, Chem. Commun., 2003, 1977.

  An object of the present invention is to provide a novel catalyst for dehydrogenation reaction. Another object of the present invention is to provide a method capable of efficiently producing ketones, aldehydes, and carboxylic acids from alcohols, and to provide a method for efficiently producing hydrogen from alcohols, formic acid or formate. It is in.

  In the course of diligent research to achieve the above-mentioned object, the present inventors have conducted a dehydrogenation reaction of alcohol and formic acid or formate by a catalyst containing a neutral organometallic compound containing a ligand having carbonyl oxygen and nitrogen. In the course of further investigation, the catalyst efficiency and reaction yield can be remarkably improved by the new complex. Furthermore, not only dehydrogenation but also reversible dehydrogenation-hydrogenation interconversion The inventors have found that the process can be repeated quantitatively with the release and absorption of hydrogen, and the present invention has been completed.

  According to the catalyst of the present invention, a cooxidant is not required, and the alcohol dehydrogenation reaction and the formic acid or formate decomposition reaction can be realized in high yield. Since the complex of the present invention is a neutral complex and exhibits high solubility in most common organic solvents, a solvent having various boiling points can be arbitrarily selected and used. It is also possible to select and use a solvent that easily dissolves the substrate. Furthermore, according to the present invention, since the decomposition reaction of formic acid or formate can be carried out at a reaction temperature of 100 ° C. or less, it is extremely advantageous for industrial implementation from the viewpoint of safety and economy.

In addition, according to the present invention, interconversion by reversible dehydrogenation-hydrogenation can be performed using the same catalyst. That is, the catalyst of the present invention can be used in both directions of the reaction represented by the following reaction formula, for example, if desired.
Reaction formula (I)
Where
X is a hydrogen-containing compound or an oxygen-containing compound,
Y is a compound corresponding to X, and is a carbonyl compound or an unsaturated bond-containing compound,
(I) is dehydrogenation,
(Ii) is hydrogenation.

  Especially, the catalyst containing the novel compound (complex) which has an acoligand of this invention shows very high catalyst efficiency and reaction yield, and is a very useful catalyst.

That is, the present invention relates to the following.
[1] Formula (1)
Where
Ar is an optionally substituted benzene, or an optionally substituted cyclopentadienyl group,
M is ruthenium, rhodium or iridium;
R ^{1 to} R ⁶ may be independently substituted with a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydroxy group, a sulfo group, a mercapto group, a carboxyl group, or one or more hydrogen atoms. C1-10 alkyl group, C3-15 cycloalkyl group, C6-15 aryl group, C1-10 heterocyclyl group, C2-10 alkenyl group, C2-10 alkynyl group, C1-10 alkoxy group C1-10 ester group, C1-10 fluoroalkyl group, C1-10 acyl group, C1-10 sulfonyl group, C1-10 amino group, C1-10 amide group, C1-10 sulfenyl Group or a C1-10 silyl group,
R ³ and R ⁴ may be connected to each other to form —CH═CH—, and H in —CH═CH— is independently a halogen atom, nitro group, cyano group, hydroxy group, sulfo group. Group, mercapto group, carboxyl group, one or more hydrogen atoms optionally substituted, C1-10 alkyl group, C3-15 cycloalkyl group, C6-15 aryl group, C1-10 heterocyclyl Group, C2-10 alkenyl group, C2-10 alkynyl group, C1-10 alkoxy group, C1-10 ester group, C1-10 fluoroalkyl group, C1-10 acyl group, C1-10 sulfonyl Group, C1-10 amino group, C1-10 amide group, C1-10 sulfenyl group or C1-10 silyl group,
L is selected from the group consisting of a sulfoxide ligand, a nitrogen-containing aromatic ring ligand, an amine ligand, a phosphine ligand, an ether ligand and an aco ligand;
A method for dehydrogenating an oxygen-containing compound using a catalyst containing an organometallic compound represented by the formula:

[2] The method according to [1], wherein the oxygen-containing compound is an alcohol.
[3] The method according to [1], wherein the oxygen-containing compound is formic acid or formate.
[4] The method according to any one of [1] to [3], wherein L is an acoligand.
[5] The method according to any one of [1] to [4], wherein Ar is a cyclopentadienyl group which may have a substituent, and M is iridium.

[6] A dehydrogenation catalyst containing an organometallic compound represented by the formula (1) used in the method according to any one of [1] to [5].
[7] A method for producing a carbonyl compound, wherein the corresponding carbonyl compound is produced by dehydrogenation of an alcohol using the dehydrogenation method according to any one of [1] to [5].
[8] The method according to [7], wherein the carbonyl compound is a ketone or an aldehyde.
[9] The method according to [7], wherein the alcohol is a primary alcohol, the carbonyl compound is a carboxylic acid, and a solvent containing water is used.
[10] Using the dehydrogenation method according to any one of [1] to [5], hydrogen is generated by dehydrogenation of alcohol, a mixture containing alcohol and water, formic acid or formate. , A method for producing hydrogen.

[11]
Formula (1)
Where
Ar is an optionally substituted benzene, or an optionally substituted cyclopentadienyl group,
M is ruthenium, rhodium or iridium;
R ^{1 to} R ⁶ may be independently substituted with a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydroxy group, a sulfo group, a mercapto group, a carboxyl group, or one or more hydrogen atoms. C1-10 alkyl group, C3-15 cycloalkyl group, C6-15 aryl group, C1-10 heterocyclyl group, C2-10 alkenyl group, C2-10 alkynyl group, C1-10 alkoxy group C1-10 ester group, C1-10 fluoroalkyl group, C1-10 acyl group, C1-10 sulfonyl group, C1-10 amino group, C1-10 amide group, C1-10 sulfenyl Group or a C1-10 silyl group,
R ³ and R ⁴ may be connected to each other to form —CH═CH—, and H in —CH═CH— is independently a halogen atom, nitro group, cyano group, hydroxy group, sulfo group. Group, mercapto group, carboxyl group, one or more hydrogen atoms optionally substituted, C1-10 alkyl group, C3-15 cycloalkyl group, C6-15 aryl group, C1-10 heterocyclyl Group, C2-10 alkenyl group, C2-10 alkynyl group, C1-10 alkoxy group, C1-10 ester group, C1-10 fluoroalkyl group, C1-10 acyl group, C1-10 sulfonyl Group, C1-10 amino group, C1-10 amide group, C1-10 sulfenyl group or C1-10 silyl group,
L is an acoligand,
An organometallic compound represented by

[12] The organometallic compound according to [11], wherein Ar is a cyclopentadienyl group which may have a substituent, and M is iridium.
[13]
Formula (2)
Where
Ar is an optionally substituted benzene, or an optionally substituted cyclopentadienyl group,
M is ruthenium, rhodium or iridium;
R ^{1 to} R ⁶ may be independently substituted with a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydroxy group, a sulfo group, a mercapto group, a carboxyl group, or one or more hydrogen atoms. C1-10 alkyl group, C3-15 cycloalkyl group, C6-15 aryl group, C1-10 heterocyclyl group, C2-10 alkenyl group, C2-10 alkynyl group, C1-10 alkoxy group C1-10 ester group, C1-10 fluoroalkyl group, C1-10 acyl group, C1-10 sulfonyl group, C1-10 amino group, C1-10 amide group, C1-10 sulfenyl Group or a C1-10 silyl group,
R ³ and R ⁴ may be connected to each other to form —CH═CH—, and H in —CH═CH— is independently a halogen atom, nitro group, cyano group, hydroxy group, sulfo group. Group, mercapto group, carboxyl group, one or more hydrogen atoms optionally substituted, C1-10 alkyl group, C3-15 cycloalkyl group, C6-15 aryl group, C1-10 heterocyclyl Group, C2-10 alkenyl group, C2-10 alkynyl group, C1-10 alkoxy group, C1-10 ester group, C1-10 fluoroalkyl group, C1-10 acyl group, C1-10 sulfonyl Group, C1-10 amino group, C1-10 amide group, C1-10 sulfenyl group or C1-10 silyl group,
Z is Na, Li, K or Cs.
An organometallic compound represented by
[14] The organometallic compound according to [13], wherein Ar is a cyclopentadienyl group which may have a substituent, and M is iridium.
[15] A method for dehydrogenating an oxygen-containing compound using a catalyst containing the organometallic compound according to [13] or [14].
[16] The method according to [15], wherein the oxygen-containing compound is alcohol, formic acid or formate.
[17] A dehydrogenation catalyst comprising the organometallic compound according to [13] or [14].

[18] A method for producing a carbonyl compound, wherein the corresponding carbonyl compound is produced by dehydrogenation of an alcohol using the dehydrogenation method according to [15] or [16].
[19] The method according to [18], wherein the carbonyl compound is a ketone or an aldehyde.
[20] The method according to [18], wherein the alcohol is a primary alcohol, the carbonyl compound is a carboxylic acid, and a solvent containing water is used.
[21] A method for producing hydrogen, wherein the hydrogen is produced by dehydrogenation of alcohol, a mixture containing alcohol and water, formic acid or formate using the dehydrogenation method according to [16].
[22] A method for producing hydrogen continuously, in the presence of an organometallic compound represented by the general formula (1) described in [1] and / or the general formula (2) described in [13] Then, an alkali compound is added to a mixture containing alcohol and water to cause a dehydrogenation reaction, and hydrogen gas is continuously added by adding the mixture and the alkali compound one or more times in the progress of dehydrogenation. The method of manufacturing.
[23] A system for continuously producing hydrogen using the method according to [22], a reaction tank for performing a dehydrogenation reaction, a supply unit for supplying a mixture and an alkali compound, and a recovery for recovering the produced hydrogen The system including a unit.

One aspect of the present invention relates to a method for dehydrogenating an oxygen-containing compound using a catalyst containing a nitrogen-containing organometallic compound (organometallic complex) represented by the following formula (1). The organometallic complex used in the present invention is not particularly limited as long as it is a metal complex containing a ligand containing carbonyl oxygen and nitrogen on bipyridine or phenanthroline, but is typically represented by the formula (1).

In formula (1), Ar is typically a benzene or cyclopentadienyl group in which one or more hydrogen atoms may be substituted.
Specific examples of the aromatic compound in which one or more hydrogen atoms may be substituted include, but are not limited to, for example, benzene, toluene, o-, m- and p-xylene, o-, m- and p-cymene, 1,2,3-, 1,2,4- and 1,3,5-trimethylbenzene, 1,2,4,5-tetramethylbenzene, 1,2,3,4- Tetramethylbenzene, 1,3,4,5-tetramethylbenzene, pentamethylbenzene, benzene having an alkyl group such as hexamethylbenzene, benzene having an unsaturated hydrocarbon group such as benzyl, vinyl, allyl, halogen atom Benzene having a different atom such as a hydroxyl group, an alkoxy group, an ester group or an amino group. The number of substituents on the benzene ring is an arbitrary number from 1 to 6, and an arbitrary position can be selected as the substitution position. From the viewpoint of ease of complex synthesis, p-cymene, 1,3,5-trimethylbenzene and hexamethylbenzene are preferred.

  In the present invention, “optionally substituted” means that it may have an arbitrary substituent, and the substituent is not limited to this, but typically C1-10. Saturated or unsaturated hydrocarbon group, aryl group, heterocyclyl group, alkoxy group, fluoroalkyl group, acyl group, ester group, hydroxyl group, amino group, amide group, carboxyl group, sulfonyl group, nitro group, cyano group, sulfo group A phenyl group, a sulfo group, a mercapto group, a silyl group or a halogen group, in particular, a C1-10 saturated or unsaturated hydrocarbon group, aryl group, heterocyclyl group, alkoxy group, acyl group, ester group, hydroxyl group, amino group Group, sulfonyl group, silyl group or halogen group.

  Specific examples of the substituent include, but are not limited to, methyl group, ethyl group, n-propyl group, i-propyl group, butyl group, pentyl group, hexyl group, cyclohexylene group, ethenyl group, Propenyl, butenyl, phenyl, toluyl, naphthyl, pyridyl, furanyl, methoxy, ethoxy, propoxy, acetyl, propanoyl, cyclohexanecarbonyl, benzoyl, methoxycarbonyl, ethoxycarbonyl , Hydroxyl group, methylamino group, ethylamino group, dimethylamino group, methylsulfonyl group, ethylsulfonyl group, methylsilyl group, dimethylsilyl group, fluoro group, chloro group, trifluoromethyl group and the like. From the viewpoint of ease of complex synthesis, a saturated or unsaturated hydrocarbon group is preferable, and a methyl group or i-propyl group is more preferable.

Specific examples of the cyclopentadienyl group in which one or more hydrogen atoms may be substituted include, but are not limited to, for example, a cyclopentadienyl group, a methylcyclopentadienyl group, an ethylcyclopentyl group, and the like. Pentadienyl group, isopropylcyclopentadienyl group, phenylcyclopentadienyl group, benzylcyclopentadienyl group, 1,2-dimethylcyclopentadienyl group, 1,3-dimethylcyclopentadienyl group, 1, 2,3-trimethylcyclopentadienyl group, 1,2,4-trimethylcyclopentadienyl group, 1,2,3,4-tetramethylcyclopentadienyl group, 1,2,3,4,5- Examples include a pentamethylcyclopentadienyl group (Cp ^* ). In view of ease of complex synthesis, 1,2,3,4,5-pentamethylcyclopentadienyl group (Cp ^* ) is preferable.

  M in the formula (1) is any one of ruthenium, rhodium, and iridium. Iridium is preferred in terms of high catalytic activity.

R ^{1 to} R ⁶ in formula (1) are typically independently of each other a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydroxy group, a sulfo group, a mercapto group, a carboxyl group, 1 or 2 The above hydrogen atoms may be substituted, C1-10 alkyl group, C3-15 cycloalkyl group, C6-15 aryl group, C1-10 heterocyclyl group, C2-10 alkenyl group, C2- 10 alkynyl groups, C1-10 alkoxy groups, C1-10 ester groups, C1-10 fluoroalkyl groups, C1-10 acyl groups, C1-10 sulfonyl groups, C1-10 amino groups, C1-10 10 amide group, a sulfenyl group, or a silyl group of C1-10 the C1-10, ^{R 3} and ^{R 4} are linked to each other, may form a -CH = CH-, wherein H in CH═CH— is independently of each other a halogen atom, a nitro group, a cyano group, a hydroxy group, a sulfo group, a mercapto group, a carboxyl group, or one or more hydrogen atoms may be substituted. -10 alkyl group, C3-15 cycloalkyl group, C6-15 aryl group, C1-10 heterocyclyl group, C2-10 alkenyl group, C2-10 alkynyl group, C1-10 alkoxy group, C1 -10 ester group, C1-10 fluoroalkyl group, C1-10 acyl group, C1-10 sulfonyl group, C1-10 amino group, C1-10 amide group, C1-10 sulfenyl group or It may be substituted with a C1-10 silyl group.

Specific examples of R ^{1 to} R ⁶ include, but are not limited to, hydrogen atom, fluorine group, chloro group, bromine group, iodine group, trifluoromethyl group, nitro group, cyano group, hydroxyl group, Sulfo group, mercapto group, carboxyl group, methoxy group, ethoxy group, n-propoxy group, iso-propoxy group, tert-butoxy group, dimethylamino group, methyl group, ethyl group, n-propyl group, i-propyl group, tert-butyl group, isobutyl group, benzyl group, cyclohexyl group, phenyl group, vinyl group, pyridyl group, ethynyl group, group having an ester bond, acetyl group, methanesulfonyl group, ethanesulfonyl group, p-toluenesulfonyl group, trifluoro Lomethanesulfonyl group, methylsilyl group, dimethylsilyl group, trimethylsilyl group, etc. And the like. In terms of catalytic activity and high reaction yield, hydrogen atom, methyl group, ethyl group, isopropyl group, tert-butyl group, isobutyl group, benzyl group, phenyl group, 4-methoxyphenyl group, 4- (dimethylamino) ) A phenyl group is preferred.

  L in formula (1) is typically from the group consisting of sulfoxide ligands, nitrogen-containing aromatic ring ligands, amine ligands, phosphine ligands, ether ligands and aco ligands. Selected.

  Specific examples include, but are not limited to, DMSO, diphenyl sulfoxide, and methylphenyl sulfoxide as sulfoxide ligands, and pyridine, picoline, lutidine, 3-chloropyridine, 4 as nitrogen-containing aromatic ring ligands. -Chloropyridine is the amine ligand aniline, toluidine, anisidine, the phosphine ligand is triphenylphosphine, trimethylphosphine, triethylphosphine, tributylphosphine, tri-tert-butylphosphine, tricyclohexylphosphine, triethoxyphosphine Are ether ligands such as dimethyl ether, diethyl ether, diisopropyl ether, cyclopentyl methyl ether, methyl tert-butyl ether, tetrahydrofuran, 2-methyl ether. Examples include trahydrofuran and anisole.

  L is preferably a dimethyl sulfoxide ligand (dmso), a pyridine ligand (pyridine), an aniline ligand (aniline) or an aco-ligand, and exhibits an extremely high catalytic efficiency and reaction yield. A ligand is particularly preferred.

  In the present invention, a preferred organometallic complex is represented by the formula (1), wherein Ar is a cyclopentadienyl group which may have a substituent, M is iridium, and L is a dimethyl sulfoxide ligand. (Dmso), a pyridine ligand (pyridine), an aniline ligand (aniline), or an acoligand. Since the organometallic complex of the present invention is a neutral complex, it exhibits high solubility in most common organic solvents, and solvents having various boiling points can be arbitrarily selected and used. It is also possible to select and use a solvent that easily dissolves the substrate.

  From the viewpoint of catalyst efficiency and reaction yield, in particular, formula (1), where Ar is a cyclopentadienyl group which may have a substituent, M is iridium, and L is an acoligand. An organometallic complex represented by: an aco complex is preferred. The reason why this aco-complex exhibits extremely high catalyst efficiency and reaction yield is not necessarily clear, but it is considered that the aco-ligand is easily dissociated and a coordination unsaturated active species is likely to be generated.

  In the present invention, the oxygen-containing compound may be a compound containing oxygen and hydrogen, and is not limited thereto, and examples thereof include alcohol, formic acid, and formate.

  Although alcohol is not limited to this, primary alcohol and secondary alcohol may be sufficient.

Primary alcohols typically have the formula (3)
In the formula, R ⁷ is a hydrogen atom, an optionally substituted C5-C15 aromatic monocyclic or polycyclic hydrocarbon group, a heteromonocyclic or polycyclic containing a C1-C15 heteroatom. And a C1-C25 saturated or unsaturated chain or cyclic hydrocarbon group.
As the substituent in this case, for example, a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydroxy group, a sulfo group, a mercapto group, a carboxyl group, or one or more hydrogen atoms may be substituted. 10 alkyl groups, C3-15 cycloalkyl groups, C5-15 aryl groups, C1-15 heterocyclyl groups, C2-10 alkenyl groups, C2-10 alkynyl groups, C1-10 alkoxy groups, C1-10 10 ester groups, C1-10 fluoroalkyl groups, C1-10 acyl groups, C1-10 sulfonyl groups, C1-10 amino groups, C1-10 amide groups, C1-10 sulfenyl groups or C1 It can be appropriate such as 10 to 10 silyl groups.

R ⁷ is specifically a hydrogen atom, phenyl group, 2-methylphenyl, 2-ethylphenyl, 2-isopropylphenyl, 2-tert-butylphenyl, 2-methoxyphenyl, 2-chlorophenyl, 2-vinylphenyl. 3-methylphenyl, 3-ethylphenyl, 3-isopropylphenyl, 3-methoxyphenyl, 3-chlorophenyl, 3-vinylphenyl, 4-methylphenyl, 4-ethylphenyl, 4-isopropylphenyl, 4-tert-butyl Aromatic monocyclic and polycyclic groups such as phenyl, 4-vinylphenyl, cumenyl, mesityl, xylyl, 1-naphthyl, 2-naphthyl, anthryl, phenanthryl, indenyl group, thienyl, furyl, pyranyl, xanthenyl, pyridyl, pyrrolyl , Imidazolinyl, indolyl, potassium Heterocyclic and polycyclic groups such as rubazoyl and phenanthronylyl, alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl and heptyl, cyclopropyl such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl and 2-adamantyl Illustrative examples include alkyl groups, unsaturated hydrocarbon groups such as benzyl, vinyl and aryl, and ferrocenyl groups.

Secondary alcohols typically have the formula (4)
In the formula, R ⁸ and R ⁹ include the same or different, optionally substituted C5-C15 aromatic monocyclic or polycyclic hydrocarbon group, C1-C15 hetero atom. A heterocyclic monocyclic or polycyclic group, or a C1-C25 saturated or unsaturated chain or cyclic hydrocarbon group. R ⁸ and R ⁹ may be bonded to each other to form a ring.
As the substituent in this case, for example, a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydroxy group, a sulfo group, a mercapto group, a carboxyl group, or one or more hydrogen atoms may be substituted. 10 alkyl groups, C3-15 cycloalkyl groups, C5-15 aryl groups, C1-15 heterocyclyl groups, C2-10 alkenyl groups, C2-10 alkynyl groups, C1-10 alkoxy groups, C1-10 10 ester groups, C1-10 fluoroalkyl groups, C1-10 acyl groups, C1-10 sulfonyl groups, C1-10 amino groups, C1-10 amide groups, C1-10 sulfenyl groups or C1 It can be appropriate such as 10 to 10 silyl groups.

Specific examples of R ⁸ and R ⁹ include phenyl group, 2-methylphenyl, 2-ethylphenyl, 2-isopropylphenyl, 2-tert-butylphenyl, 2-methoxyphenyl, 2-chlorophenyl, and 2-vinylphenyl. 3-methylphenyl, 3-ethylphenyl, 3-isopropylphenyl, 3-methoxyphenyl, 3-chlorophenyl, 3-vinylphenyl, 4-methylphenyl, 4-ethylphenyl, 4-isopropylphenyl, 4-tert-butyl Aromatic monocyclic and polycyclic groups such as phenyl, 4-vinylphenyl, cumenyl, mesityl, xylyl, 1-naphthyl, 2-naphthyl, anthryl, phenanthryl, indenyl group, thienyl, furyl, pyranyl, xanthenyl, pyridyl, pyrrolyl , Imidazolinyl, indolyl, carbazoyl , Heteromonocyclic and polycyclic groups such as phenanthronilyl, alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl and heptyl, cycloalkyl such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl and 2-adamantyl Examples thereof include unsaturated hydrocarbon groups such as benzyl, vinyl and aryl, and ferrocenyl groups.
When R ⁸ and R ⁹ combine to form a ring, for example, saturated and unsaturated fats that give cyclic alcohols such as cyclopentanol, cyclohexanol, cycloheptanol, cyclopentenol, cyclohexenol, cycloheptenol, etc. Illustrate saturated and unsaturated alicyclic groups with cyclic groups and substituents having alkyl groups, aryl groups, unsaturated alkyl groups, chained or cyclic hydrocarbon groups containing heteroelements on each carbon. Can do.

  Examples of the formate salt include, but are not limited to, formate salts such as sodium formate and potassium formate, and metal formate such as ammonium formate.

  In this specification, dehydrogenation means a reaction in which hydrogen molecules are eliminated, and examples thereof include oxidative dehydrogenation and decomposition. The dehydrogenation method of this specification is performed by carrying out a dehydrogenation reaction.

One aspect of the present invention relates to a method for producing a corresponding carbonyl compound from the alcohol by the dehydrogenation method of the present invention. For example, when the alcohol is a primary alcohol, an aldehyde is obtained as the corresponding carbonyl compound, and is represented by the following reaction formula, for example.
R ⁷ is as described above.

In the case of a secondary alcohol, a ketone is obtained, for example, represented by the following reaction formula.
R ⁸ and R ⁹ are as described above.

  One aspect of the present invention relates to a method for producing a carboxylic acid from a primary alcohol via an aldehyde using the dehydrogenation method of the present invention. This conversion from alcohol to carboxylic acid involves three steps: 1) generation of aldehyde by dehydrogenation of alcohol, 2) formation of hemiacetal by hydration of aldehyde, and 3) formation of carboxylic acid by dehydrogenation of hemiacetal. It is thought that it is progressing. Therefore, when producing carboxylic acid, it is preferable to use a solvent containing water in order to hydrate the aldehyde and produce hemiacetal. Specific production examples include, but are not limited to, production of acetic acid from ethanol.

  One aspect of the present invention relates to a process for producing hydrogen from an alcohol, preferably a primary alcohol, using the dehydrogenation process of the present invention. The alcohol is not particularly limited, but is preferably a primary alcohol from the viewpoint of hydrogen generation efficiency, and is preferably produced by dehydrogenation of a mixed solution with water. For example, when the primary alcohol is methanol, dehydrogenation of a mixed solution of 1 mole of methanol: water = 1: 1 generates 3 moles of hydrogen molecules. All hydrogen atoms in the hydrogen atom and water molecule are converted into hydrogen molecules, which is extremely efficient as a hydrogen production method.

  In the production of hydrogen, the dehydrogenation reaction can proceed at pH 1-14. From the viewpoint of hydrogen generation efficiency, pH 5 to 14 is preferable, and pH 10 to 14 is particularly preferable. As the reaction proceeds, carbon dioxide is generated and the reaction system is gradually acidified. Therefore, by setting the pH at the start of the reaction to 13 or more, efficient hydrogenation can be continued for a long time.

  According to the present invention, carboxylic acid and hydrogen can be obtained simultaneously from a primary alcohol. This makes it possible to simultaneously obtain carboxylic acid that is important in organic industrial chemistry and hydrogen that is useful as clean energy, using alcohol obtained by fermentation from biomass resources as a raw material.

  One aspect of the present invention relates to a method for producing hydrogen from formic acid or formate by a decomposition reaction using the dehydrogenation method of the present invention. According to the present invention, since the reaction can be carried out at a reaction temperature of about 60 to 90 ° C., it is excellent in safety and economy and is extremely advantageous for industrialization.

  In the dehydrogenation process of the present invention, the amount of catalyst used is the molar ratio of alcohol, formic acid or formate to ruthenium, rhodium or iridium complex, S / C (S is the number of moles of alcohol, formic acid or formate, C Represents the number of moles of catalyst). In that case, the extent to which S / C can be increased greatly varies depending on the structure of the substrate, the type of catalyst, the concentration, the reaction temperature, the type of reaction solvent, etc., but in practice, S / C is about 50 to 500,000. It is desirable to set.

The dehydrogenation reaction of the present invention is carried out without solvent or in the presence of a solvent. When a solvent is used, the reaction solvent can be selected in a timely manner in consideration of the physical properties and chemical properties of the catalyst, the substrate, and the product. Protic solvents, aprotic solvents, ionic liquids, water and buffers can be used alone or in combination.
Specific examples of the solvent include, but are not limited to, pentane, hexane, heptane, benzene, toluene, xylene, tetrahydrofuran, diisopropyl ether, dichloromethane, dimethylformamide, t-butanol, and water.

The reaction temperature is preferably about −20 ° C. to 200 ° C., more preferably 20 ° C. to 150 ° C., considering the solubility, reactivity, and economy of the catalyst, substrate and product. is there.
The reaction time varies depending on the reaction conditions such as the substrate concentration and reaction temperature, but the reaction is completed in several minutes to 100 hours.
Purification of the carbonyl compound produced by the dehydrogenation reaction can be performed by a known method such as acid-base extraction, column chromatography, distillation, recrystallization, or a combination thereof in a timely manner.

According to the dehydrogenation method of the present invention, the reaction is possible in a wide pH range. In the alcohol dehydrogenation reaction, the pH may be 1 to 14, preferably 4 to 10, and preferably 6 to 8 from the viewpoint of synthetic chemistry.
In the production of carboxylic acid, the pH can change to the acidic side as the carboxylic acid is produced, but the reaction proceeds in the region of pH 1-14. It is preferable from the viewpoint of synthetic chemistry to start at pH 6 to 8, which is a neutral region, and from the viewpoint of the production efficiency of carboxylic acid, it is preferable that the pH of the reaction system is within the range of 1 to 10 throughout. It is preferably within the range of pH 1-8.

One aspect of the present invention is the following formula (1):
Formula (1)
Where
Ar is an optionally substituted benzene, or an optionally substituted cyclopentadienyl group,
M is ruthenium, rhodium or iridium;
R ^{1 to} R ⁶ may be independently substituted with a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydroxy group, a sulfo group, a mercapto group, a carboxyl group, or one or more hydrogen atoms. C1-10 alkyl group, C3-15 cycloalkyl group, C6-15 aryl group, C1-10 heterocyclyl group, C2-10 alkenyl group, C2-10 alkynyl group, C1-10 alkoxy group C1-10 ester group, C1-10 fluoroalkyl group, C1-10 acyl group, C1-10 sulfonyl group, C1-10 amino group, C1-10 amide group, C1-10 sulfenyl Group or a C1-10 silyl group,
R ³ and R ⁴ may be connected to each other to form —CH═CH—, and H in —CH═CH— is independently a halogen atom, nitro group, cyano group, hydroxy group, sulfo group. Group, mercapto group, carboxyl group, one or more hydrogen atoms optionally substituted, C1-10 alkyl group, C3-15 cycloalkyl group, C6-15 aryl group, C1-10 heterocyclyl Group, C2-10 alkenyl group, C2-10 alkynyl group, C1-10 alkoxy group, C1-10 ester group, C1-10 fluoroalkyl group, C1-10 acyl group, C1-10 sulfonyl Group, C1-10 amino group, C1-10 amide group, C1-10 sulfenyl group or C1-10 silyl group,
L is an acoligand,
It is related with the organometallic compound represented by these.

One aspect of the present invention is the following formula (2):
Where
Ar is an optionally substituted benzene, or an optionally substituted cyclopentadienyl group,
M is ruthenium, rhodium or iridium;
R ^{1 to} R ⁶ may be independently substituted with a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydroxy group, a sulfo group, a mercapto group, a carboxyl group, or one or more hydrogen atoms. C1-10 alkyl group, C3-15 cycloalkyl group, C6-15 aryl group, C1-10 heterocyclyl group, C2-10 alkenyl group, C2-10 alkynyl group, C1-10 alkoxy group C1-10 ester group, C1-10 fluoroalkyl group, C1-10 acyl group, C1-10 sulfonyl group, C1-10 amino group, C1-10 amide group, C1-10 sulfenyl Group or a C1-10 silyl group,
R ³ and R ⁴ may be connected to each other to form —CH═CH—, and H in —CH═CH— is independently a halogen atom, nitro group, cyano group, hydroxy group, sulfo group. Group, mercapto group, carboxyl group, one or more hydrogen atoms optionally substituted, C1-10 alkyl group, C3-15 cycloalkyl group, C6-15 aryl group, C1-10 heterocyclyl Group, C2-10 alkenyl group, C2-10 alkynyl group, C1-10 alkoxy group, C1-10 ester group, C1-10 fluoroalkyl group, C1-10 acyl group, C1-10 sulfonyl Group, C1-10 amino group, C1-10 amide group, C1-10 sulfenyl group or C1-10 silyl group,
Z is Na, Li, K or Cs.
It is related with the organometallic compound represented by these.

  The compound represented by the formula (2) can be produced by reacting an organometallic compound in which L is an acoligand and an alkali compound in the formula (1). Examples of the alkali compound include, but are not limited to, sodium hydroxide, lithium hydroxide, potassium hydroxide, and cesium hydroxide. Therefore, the compound represented by the formula (2) can be reacted by adding an alkali compound in the dehydrogenation reaction using the organometallic compound represented by the formula (1) in which L is an acoligand as a catalyst. It may be generated in the system.

  The compound represented by the formula (2) is the same as the compound represented by the formula (1) in the dehydrogenation method, the carbonyl compound production method, the hydrogen production method and the like described above for the compound represented by the formula (1). It can be used as well. Therefore, this invention relates to the catalyst for dehydrogenation containing the compound represented by Formula (2).

The method for producing hydrogen according to the present invention comprises continuously producing hydrogen from a mixture of alcohol and water. In particular, from the viewpoint of efficiency, it is preferable to use the compound represented by the formula (2).
Examples of the method for continuously producing hydrogen include a sequential addition method and a continuous addition method. In the sequential addition method, hydrogen was generated by adding a compound represented by the formula (1) and / or the formula (2) and an alkali compound to a mixture of alcohol and water, and heating and reacting under reflux. Thereafter, alcohol and water corresponding to the consumed amount are added, and further an alkali compound is added. The pH after each addition is preferably equal to the pH at the start of the reaction. In this way, hydrogen can be continuously produced by sequentially adding consumption.

In the continuous addition method, a compound represented by formula (1) and / or formula (2) and an alkali compound are added to a mixture of alcohol and water, and the reaction system is started under reflux by heating. For example, a syringe pump Using a microfeeder or the like, a mixture of alcohol, water and an alkali compound mixed in advance is continuously added at a constant rate while refluxing is continued. In this way, by continuously reacting raw materials (alcohol and water) consumed at a constant rate and sodium hydroxide while supplementing the amount corresponding to the consumption rate, hydrogen gas is supplied at a substantially constant rate. Can be manufactured for a long time.
According to the hydrogen production method of continuously producing hydrogen according to the present invention, the catalyst rotation speed is 2 times or more, and can be 100 times or more, preferably 1000 times or more, more preferably 3500 times or more. Therefore, it is possible to construct a new system that is extremely efficient and highly practical.

  The system for continuously producing hydrogen includes, but is not limited to, a system including a reaction tank, a supply unit, and a recovery unit. The reaction vessel is not particularly limited as long as the raw material can be dehydrogenated under a catalyst, but is preferably capable of continuing the reaction, and typically includes a device capable of heating and refluxing. The supply unit typically includes supply means such as a storage tank for storing raw materials and alkali compounds for addition, a syringe pump, and a microfeeder. The recovery unit is not particularly limited as long as it recovers the generated hydrogen, and examples thereof include a gas burette, a gas bag, and a gas tank.

One aspect of the present invention relates not only to dehydrogenation reactions, but also to interconversion by hydrogenation and reversible dehydrogenation-hydrogenation. For example,
Reaction formula (II)
Where
R ⁸ and R ⁹ are as described above,
(I) is a dehydrogenation reaction, (ii) is a hydrogenation,
In the catalytic reaction represented by the formula (1), the catalyst of the present invention can repeatedly perform the mutual conversion of the bidirectional catalytic reaction (i) and (ii) quantitatively with the release and absorption of hydrogen.
It is considered possible to develop a hydrogen storage system by performing the dehydrogenation reaction and hydrogenation reversibly and continuously using the same catalyst.

  EXAMPLES Hereinafter, although an Example is shown and this invention is demonstrated in detail, this invention is not limited by these Examples.

  The reactions described in the following examples were performed in an inert gas atmosphere of argon gas or nitrogen gas. The alcohol used was a commercially available reagent. For identification of the complex and the reactant, a nuclear magnetic resonance apparatus (NMR) was used, tetramethylsilane (TMS) was used as an internal standard substance, and the signal was δ = 0 (δ is a chemical shift). The conversion rate and yield to carbonyl compounds and hydrogen were determined by gas chromatography (GC). As the NMR apparatus, JOEL ECX-500 and JOEL ECS-400 (manufactured by JEOL Ltd.) were used, and as the GC apparatus, GL-Sciences GC353B (manufactured by GL Sciences Inc.) was used.

<Synthesis of a novel neutral iridium complex catalyst>
[Production Example 1]
Neutral iridium complex 1 was produced by either method shown in Production Example 1-a or 1-b.
[Production Example 1-a]
As shown in Synthesis Scheme 1-a, a dicationic Cp ^* iridium-aco complex (407.8 mg, 0.60 mmol) is converted to a 6,6′-dihydroxy-2,2′-bipyridine ligand (113.8 mg, 0 .60 mmol) was allowed to act in an aqueous solvent (12 mL) to obtain Complex A (yield 93%). Subsequently, neutral iridium complex 1 is obtained by allowing sodium t-butoxide (211.4 mg, 2.2 mmol) to act on complex A (915.0 mg, 1.1 mmol) in an aqueous solvent (30 mL). (Yield 84%).

[Production Example 1-b]
As shown in Scheme 1-b, [Cp ^* IrCl ₂ ] ₂ (458.4 mg, 0.570 mmol) was converted to 6,6′-dihydroxy-2,2′-bipyridine ligand (250.0 mg, 1.33 mmol). ) In methanol solvent (8 mL), reacted at 60 ° C. for 3 hours, and then filtered through a glass filter to obtain a cationic complex A ′ (yield 74%). Subsequently, the cationic complex A ′ (100.0 mg, 0.170 mmol) and potassium t-butoxide (38.3 mg, 0.340 mmol) were reacted in water (5 mL) by stirring at room temperature for 30 minutes to precipitate. The solid was filtered to obtain Complex 1 (yield 64%).

¹ H NMR (400 MHz, CD ₃ OD) δ 7.43 (t, J = 8 Hz, 2H), 6.92 (d, J = 8 Hz, 2H), 6.43 (d, J = 8 Hz, 2H), 1.59 ( ¹³ C { ¹ H} NMR (125.8 MHz, CD ₃ OD) δ 170.9, 157.3, 139.9, 118.1, 106.9, 88.0, 9.83. Anal. Calcd for C ₂₀ H ₂₃ O ₃ N ₂ Ir: C , 45.18; H, 4.36; N, 5.27. Found: C, 45.47; H, 4.01; N, 5.62.

[Production Example 2] As shown in the synthesis scheme 2 neutral iridium complex _{^{2, [Cp * IrCl 2]}} 2 (240.0mg, 0.301mmol) in 2,9-dihydroxy-1,10-phenanthroline ligands (150.1 mg, 0.707 mmol) was allowed to act in a methanol solvent (5.4 mL), reacted at 60 ° C. for 4 hours, and then filtered through a glass filter to obtain a cationic complex T (yield 60 %). Subsequently, the cationic complex T (150 mg, 0.229 mmol) and potassium t-butoxide (51.4 mg, 0.421 mmol) were reacted in water (6.8 mL) by stirring at room temperature for 30 minutes, under vacuum. The solvent was distilled off. Toluene (15 mL) was added to the residue for extraction, and after distilling off the solvent, recrystallization was performed using ethanol (2 mL) and water (18 mL) to obtain Complex 2 (yield 73%).

¹ H NMR (400 MHz, CDCl ₃ ) δ 7.78 (d, J = 9 Hz, 2H), 7.16 (s, 2H), 6.81 (d, J = 9 Hz, 2H), 1.86 (s, 15H). ¹³ C { ¹ H} NMR (125.8 MHz, CDCl ₃ ) δ168.7, 146.1, 139.1, 123.5, 119.2, 118.8, 91.7, 10.8.

[Production Example 3] Synthesis of neutral iridium complex B Cationic complex A '(150.6 mg, 0.240 mmol), potassium t-butoxide (80.5 mg, 0.718 mmol) and pyridine (101.1 mg, 1.278 mmol) ) In dichloromethane (10 mL) with stirring at room temperature overnight and the solvent was removed in vacuo. Toluene (15 mL) was added to the residue for extraction, and then the solvent was distilled off to obtain Complex B (yield 75%).

¹ H NMR (500 MHz, CD ₂ Cl ₂ ) δ9.87 (d, J = 8 Hz, 2H), 7.58 (t, J = 8 Hz, 1H), 7.16 (d, J = 8 Hz, 2H), 6.22 (d, J = 8 Hz , 2H) δ1.50 (s, 15H). 13 C {1 H} NMR (125.8 MHz, CD 2 Cl 2) δ168.8, 158.4, 157.4, 136.9, 136.7, 125.7, 117.6, 103.4, 88.2, 9.4.

[Production Example 4] Synthesis of neutral iridium complex C Cationic complex A '(150.6 mg, 0.240 mmol), potassium t-butoxide (80.5 mg, 0.718 mmol) and aniline (35.7 mg, 0.360 mmol) ) In dichloromethane (10 mL) with stirring at room temperature overnight and the solvent was removed in vacuo. Toluene (15 mL) was added to the residue for extraction, and then the solvent was distilled off to obtain Complex C (yield 70%).

¹ H NMR (500 MHz, CD ₂ Cl ₂ ) δ7.49 (bs, 1H), 7.27 (bs, 2H), 7.23 (t, J = 8 Hz, 2H), 7.06 (bs, 1H), 6.52 (d , J = 7 Hz, 2H), 6.22 (d, J = 8 Hz, 2H), 5.79 (bs, 1H), 1.28 (s, 15H). ¹³ C { ¹ H} NMR (125.8 MHz, CD ₂ Cl ₂ ) δ169.1, 156.1, 141.5, 137.5, 128.6, 125.2, 122.5, 117.0, 103.4, 86.6, 8.4.

[Production Example 5] Synthesis of neutral iridium complex D Cationic complex A ′ (150.6 mg, 0.240 mmol), potassium t-butoxide (80.5 mg, 0.718 mmol), and dimethyl sulfoxide (18.3 mg, 0.24 mmol). 234 mmol) was reacted in dichloromethane (10 mL) with stirring overnight at room temperature and the solvent was distilled off under vacuum. Toluene (15 mL) was added to the residue for extraction, and then the solvent was distilled off to obtain Complex D (yield 61%).

¹ H NMR (500 MHz, CD ₂ Cl ₂ ) δ7.15 (t, J = 8 Hz, 2H), 6.46 (d, J = 8 Hz, 2H), 6.13 (d, J = 8 Hz, 2H), 2.89 (bs, 6H), 1.56 (s, 15H). 13 C {1 H} NMR (100.5 MHz, CD 2 Cl 2) δ168.2, 156.6, 137.2, 117.2, 103.9, 95.1, 46.1, 9.0.

[Production Example 6] Synthesis of neutral iridium complex E Cationic complex T (150.6 mg, 0.230 mmol), potassium t-butoxide (79.2 mg, 0.706 mmol) and pyridine (90.5 mg, 1.144 mmol) Was reacted in dichloromethane (10 mL) with stirring overnight at room temperature, and the solvent was removed in vacuo. Toluene (15 mL) was added to the residue for extraction, and then the solvent was distilled off to obtain Complex E (yield 82%).

¹ H NMR (500 MHz, CDCl ₃ ) δ9.65 (d, J = 5 Hz, 1H), 7.56 (d, J = 8 Hz, 2H), 7.53 (t, J = 8 Hz, 2H), 7.19 ( t, J = 7 Hz, 2H), 6.68 (d, J = 8 Hz, 2H), 1.59 (s, 15H). ¹³ C { ¹ H} NMR (125.8 MHz, CD ₂ Cl ₂ ) δ168.2, 158.2 , 147.4, 136.9, 136.8, 125.9, 122.6, 120.8, 118.7, 88.2, 10.0.

  Next, a dehydrogenation reaction using the synthesized complex as a catalyst will be exemplified. The structural formula of the complex used in the examples is shown below.

Complexes used in the examples

[Example 1]
<Synthesis of acetophenone by dehydrogenation of racemic 1-phenylethanol>
In an inert gas atmosphere, in a 50 mL two-necked eggplant flask, 3 mL of dehydrated pentane, 122.2 mg (1.0 mmol) of racemic 1-phenylethanol, and 2.7 mg (0.005 mmol, 0.5 mol%) of Complex 1 In addition, the mixture was stirred for 5 hours under reflux conditions. After 10 mL of toluene was added to make uniform, the reaction solution was analyzed by GC. As shown in Table 1, it was confirmed that the corresponding acetophenone was produced at a conversion rate of 100% and a yield of 100%.

[Example 2]
<Synthesis of acetophenone by dehydrogenation of racemic 1-phenylethanol>
The reaction was carried out under the same conditions as in Example 1 except that 2.8 mg (0.005 mmol, 0.5 mol%) of Complex 2 was used as a catalyst. As a result of GC analysis, as shown in Table 1, it was confirmed that acetophenone was produced at a conversion rate of 37% and a yield of 36%.

[Examples 3 to 6]
<Synthesis of acetophenone by dehydrogenation of racemic 1-phenylethanol>
The reaction was carried out under the same conditions as in Example 1 except that various complex catalysts B to E (0.005 mmol) shown in Table 1 were used as the catalyst. The results of GC analysis are summarized in Table 1. It was confirmed that acetophenone was formed.

[Example 7]
<Synthesis of acetophenone by dehydrogenative oxidation of racemic 1-phenylethanol>
In an inert gas atmosphere, in a 50 mL two-necked eggplant flask, 3 mL of dehydrated pentane, 122.2 mg (1.0 mmol) of racemic 1-phenylethanol, and 2.7 mg (0.005 mmol, 0.5 mol%) of Complex 1 In addition, the mixture was stirred for 5 hours under reflux conditions. After 10 mL of toluene was added to make it uniform, the reaction solution was analyzed by GC. As shown in Table 2, it was confirmed that the corresponding acetophenone was produced at a conversion rate of 100% and a yield of 100%.

[Comparative Example 1]
<Synthesis of acetophenone by dehydrogenative oxidation of racemic 1-phenylethanol>
The reaction was carried out under the same conditions as in Example 7 except that Complex A (0.005 mmol) was used as the catalyst. As a result of GC analysis, as shown in Table 2, acetophenone was produced with a conversion rate of 19% and a yield of 18%. Compared to Example 7, the yield was clearly lower, indicating the usefulness of the present invention.

[Comparative Example 2]
<Synthesis of acetophenone by dehydrogenative oxidation of racemic 1-phenylethanol>
The reaction was carried out under the same conditions as in Example 7 except that Complex A (0.005 mmol) was used as the catalyst and water was used as the reaction solvent. As a result of GC analysis, as shown in Table 2, acetophenone was produced at a conversion rate of 6% and a yield of 4%. Compared to Example 7, the yield was clearly lower, indicating the usefulness of the present invention.

[Comparative Example 3]
<Synthesis of acetophenone by dehydrogenative oxidation of racemic 1-phenylethanol>
The reaction was carried out under the same conditions as in Example 7 except that the reaction was carried out at 80 ° C. using Complex A (0.005 mmol) as the catalyst and water as the reaction solvent. As a result of GC analysis, as shown in Table 2, acetophenone was produced at a conversion rate of 12% and a yield of 11%. Compared to Example 7, the yield was clearly lower, indicating the usefulness of the present invention.

[Examples 8 to 14]
<Synthesis of ketones by dehydrogenative oxidation of secondary alcohols>
Using complex 1 as a catalyst, various secondary alcohols were subjected to dehydrogenative oxidation reaction under the reaction conditions shown in Table 3. After completion of the reaction, the reaction solution was analyzed by GC. As a result, it was confirmed that the corresponding ketone was produced with high conversion and high yield.

[Example 15]
<Synthesis of acetophenone by dehydrogenative oxidation of racemic 1-phenylethanol>
To a 1000 mL eggplant flask, 500 mL of dehydrated p-xylene, 61.06 g (500 mmol) of racemic 1-phenylethanol, and 0.53 mg (0.001 mmol, 0.0002 mol%) of Complex 1 were added and stirred for 48 hours under reflux conditions. did. After adding dichloromethane to make it uniform, the reaction solution was analyzed by GC, and it was confirmed that the corresponding acetophenone was produced in a yield of 55%. This reaction showed a high catalyst rotation speed (TON = 275,000), indicating the usefulness of the present invention.

[Example 16]
<Synthesis of estrone by dehydrogenative oxidation of β-estradiol>
To a 50 mL one-necked eggplant flask, 3 mL of tert-butyl alcohol, 272.4 mg (1.0 mmol) of β-estradiol and 2.7 mg (0.005 mmol, 0.5 mol%) of Complex 1 were added, and the mixture was stirred for 20 hours under reflux conditions did. When the solvent of the reaction solution was distilled off and analyzed by NMR, it was confirmed that the corresponding estrone was produced at a yield of 100%.

[Example 17]
<Synthesis of benzaldehyde by dehydrogenative oxidation of benzyl alcohol>
To a 50 mL eggplant flask, 10 mL of tert-butyl alcohol, 54.0 mg (0.5 mmol) of benzyl alcohol, and 4.0 mg (0.0075 mmol, 1.5 mol%) of Complex 1 were added and stirred for 20 hours under reflux conditions. After 10 mL of dichloromethane was added to make it uniform, the reaction solution was analyzed by GC. As shown in Table 4, it was confirmed that the corresponding benzaldehyde was produced at a conversion rate of 92% and a yield of 92%.

[Examples 18 to 20]
<Synthesis of aldehydes by dehydrogenative oxidation of primary alcohols>
The reaction was carried out under the same conditions as in Example 17 except that various primary alcohols (0.5 mmol) shown in Table 4 were used as the substrate. The results of GC analysis are summarized in Table 4.

[Example 21]
<Synthesis of 4- (trifluoromethyl) benzaldehyde by dehydrogenative oxidation of 4- (trifluoromethyl) benzyl alcohol>
To a 50 mL eggplant flask, 10 mL of dehydrated heptane, 88.5 mg (0.5 mmol) of 4- (trifluoromethyl) benzyl alcohol, and 7.9 mg (0.015 mmol, 3.0 mol%) of Complex 1 were added, and the mixture was refluxed. Stir for 20 hours. After adding 10 mL of dichloromethane and homogenizing it, the reaction solution was analyzed by GC. As shown in Table 4, the corresponding 4- (trifluoromethyl) benzaldehyde was produced at a conversion rate of 89% and a yield of 88%. It was confirmed.

[Example 22]
<Synthesis of cyclohexanecarboxaldehyde by dehydrogenative oxidation of cyclohexanemethanol>
To a 50 mL eggplant flask, 10 mL of dehydrated toluene, 56.2 mg (0.5 mmol) of cyclohexanemethanol, and 6.5 mg (0.012 mmol, 2.5 mol%) of Complex 1 were added and stirred for 20 hours under reflux conditions. After adding 10 mL of toluene and homogenizing it, the reaction solution was analyzed by GC. As shown in Table 4, it was confirmed that the corresponding cyclohexanecarboxaldehyde was produced at a conversion rate of 82% and a yield of 81%.

[Example 23]
<Synthesis of n-octanal by dehydrogenative oxidation of 1-octanol>
10 mL of dehydrated toluene, 65.2 mg (0.5 mmol) of 1-octanol and 13.2 mg (0.025 mmol, 5.0 mol%) of Complex 1 were added to a 50 mL eggplant flask, and the mixture was stirred under reflux conditions for 20 hours. After adding 10 mL of toluene to make it uniform, the reaction solution was analyzed by GC. As shown in Table 4, it was confirmed that the corresponding n-octanal was produced at a conversion rate of 89% and a yield of 87%.

[Example 24]
<Synthesis of benzaldehyde by dehydrogenative oxidation of benzyl alcohol>
To a 500 mL eggplant flask, 270 mL of dehydrated toluene, 8.648 g (80 mmol) of benzyl alcohol, and 0.85 mg (0.0016 mmol, 0.002 mol%) of Complex 1 were added and stirred for 48 hours under reflux conditions. After adding toluene to make it uniform, the reaction solution was analyzed by GC, and it was confirmed that the corresponding benzaldehyde was produced at a yield of 95%. Since this reaction showed a high catalyst rotation speed (TON = 47,500), the usefulness of the present invention was shown.

[Example 25]
<Synthesis of acetophenone by dehydrogenative oxidation of racemic 1-phenylethanol (under solvent-free conditions)>
In a 50 mL two-necked eggplant flask, 610.4 mg (5.0 mmol) of racemic 1-phenylethanol and 79.7 mg (0.15 mmol, 3.0 mol%) of Complex 1 were added and stirred at 60 ° C. for 20 hours. After adding 100 mL of dichloromethane and homogenizing it, the reaction solution was analyzed by GC. As shown in Table 5, it was confirmed that the corresponding acetophenone was produced at a conversion rate of 95% and a yield of 93%.

[Examples 26 to 28]
<Synthesis of aldehydes by dehydrogenative oxidation of alcohol (under solvent-free conditions)>
The reaction was carried out under the same conditions as in Example 25 except that various alcohols (5.0 mmol) shown in Table 5 were used as substrates and the reaction temperature was 90 ° C. The results of GC analysis are summarized in Table 5.

[Comparative Example 4]
<Synthesis of acetophenone by dehydrogenative oxidation of racemic 1-phenylethanol (under solvent-free conditions)>
The reaction was carried out under the same conditions as in Example 25 except that Complex A (0.15 mmol) was used as the catalyst. As a result of GC analysis, the conversion rate was 93% as shown in Table 5, but the acetophenone yield was 5%. Compared with Example 25, the yield was clearly low, indicating the usefulness of the present invention.

[Example 29]
<Synthesis of acetic acid via dehydrogenative oxidation of ethanol>
Ethanol (460.7 mg, 10 mmol), water (360.4 mg, 20 mmol), and Complex 1 (159.7 mg, 0.3 mmol, 3.0 mol%) were added to a 10 mL test tube, and the mixture was stirred under reflux conditions for 20 hours. When the reaction solution was analyzed by NMR, it was confirmed that acetic acid was produced in a yield of 75%. Further, when the generated gas was analyzed, it was confirmed that hydrogen was produced with a yield of 84%. The usefulness of the present invention was shown because acetic acid important in organic industrial chemistry and hydrogen useful as clean energy can be obtained simultaneously using ethanol obtained by fermentation from biomass resources as a raw material.

[Example 30]
<Production of hydrogen by dehydrogenative oxidation of 2-propanol>
To a 10 mL test tube, 901.6 mg (15 mmol) of 2-propanol and 159.5 mg (0.3 mmol, 2.0 mol%) of Complex 1 were added, and the mixture was stirred for 4 hours under reflux conditions. When the reaction liquid was analyzed by GC, it was confirmed that acetone was produced in a yield of 98%. Further, when the generated gas was analyzed, it was confirmed that hydrogen was produced with a yield of 91%.

[Example 31]
<Hydrogenation of acetone>
Under an inert gas atmosphere, 99.6 mg (0.15 mmol, 0.5 mol%) of Complex 1 was taken in a 30 mL two-necked eggplant flask, and after hydrogen substitution, 1.7418 g (30.0 mmol) of acetone was added, A balloon filled with hydrogen was put on and stirred at 40 ° C. for 4 hours. When the reaction liquid was analyzed by GC, it was confirmed that 2-propanol was produced with a yield of 95%.

[Example 32]
<Production of hydrogen by dehydrogenative oxidation of methanol>
Add 150.4 mg (10 mmol) of methanol, 150.2 mg (10 mmol) of water, and 159.5 mg (0.3 mmol, 3.0 mol%) of Complex 1 to a 10 mL test tube, and reach pH> 13 using a pH meter. After adding an aqueous sodium hydroxide solution, the mixture was stirred for 20 hours under reflux conditions. When the generated gas was analyzed, it was confirmed that hydrogen was produced in a yield of 99%.

[Example 33]
<Production of hydrogen by dehydrogenative oxidation of formic acid>
460.6 mg (10 mmol) of formic acid and 2.6 mg (0.005 mmol, 0.05 mol%) of complex 1 were added to a 10 mL test tube, and the mixture was stirred at 60 ° C. for 21 minutes. When the generated gas was analyzed, it was confirmed that hydrogen was produced with a yield of 94%. The usefulness of the present invention was shown because hydrogen can be produced by decomposing formic acid in a short time with a small amount of catalyst.

[Production Example 7]
<Synthesis of anionic iridium complex having functional bipyridonate ligand>
When neutral iridium complex 1 (1.0630 g, 2.0 mmol) is taken in a flask and 1.0 M aqueous sodium hydroxide solution (3.0 mL, 3.0 mmol) is added and reacted at room temperature, a black-green uniform solution is obtained. became. Thereafter, the solution was transferred to a microtube, and left standing in the open state for crystallization to give a novel anionic complex 3 having a sodium ion as a counter ion in a yield of 72% (796.5 mg, 1.. 4 mmol).

¹ H NMR (500 MHz, D ₂ O) δ 7.46 (t, J = 8.0 Hz, 2H), 7.03 (d, J = 6.5 Hz, 2H), 6.42 (d, J = 7.5 Hz, 2H), 1.49 ( ¹³ C { ¹ H} NMR (125.8 MHz, D ₂ O) δ 170.6, 156.9, 139.3, 116.8, 107.4, 85.6, 9.39. Anal.Calcd for C ₂₀ H ₂₂ O ₃ N ₂ NaIr ・ H ₂ O: C, 42.02; H, 4.23; N, 4.90. Found: C, 42.07; H, 4.64; N, 4.93.

The catalytic reaction using the complex 3, the dicationic complex A and the neutral iridium complex 1 as catalysts was examined below.

[Example 34]
<Hydrogen generation reaction from a mixture of methanol and water>
A dehydrogenation reaction from a mixture of methanol and water was performed using the aforementioned complexes A, 1 and 3 as catalysts. In the reaction, methanol and water were used as raw materials, heated and refluxed in the presence of a catalyst, and the generated gas was collected in a gas burette and quantified. Note that 75% of the gas volume was regarded as hydrogen, and the hydrogen volume and its yield were calculated and listed in the table. First, the activity of each catalyst was compared by heating and refluxing for 20 hours in the presence of Catalysts A, 1 and 3 (0.5 mol%) using equal amounts of methanol (20 mmol) and water (20 mmol) as raw materials ( entry 1-3). When dicationic catalyst A or neutral catalyst 1 was used, the reaction hardly proceeded and only a very small amount of hydrogen was observed (entries 1 and 2), but anionic catalyst 3 was used. As a result, the reaction proceeded, and 120 mL (yield 8%) of hydrogen could be obtained (entry 3). Next, when the equivalent of water with respect to methanol was changed (entry 3-5), the amount of generated hydrogen was maximized when 4 equivalents of water were used (150 mL, yield 10%, entry 4). Subsequently, carbon dioxide is generated as the reaction proceeds in this catalyst system, so that the system is gradually acidified, and the catalyst molecules are converted from the anionic complex 3 to the neutral complex 1 and further to the dicationic complex A. In order to prevent this, it was examined to add a base (sodium hydroxide) as an additive (entry 6-9). As a result, the yield of hydrogen was greatly improved, and optimum conditions were obtained when 0.5 mol% of sodium hydroxide was added, and 1223 mL (yield 84%) of hydrogen could be obtained (entry 7).

[Example 35]
<Method of generating hydrogen from methanol and water (sequential addition method)>

The construction of a catalyst system that continuously generates hydrogen from a mixture of methanol and water was investigated.
First, catalyst 3 (0.1 mol%) and sodium hydroxide (0.5 mol%) were added to a mixture of methanol (20 mmol) and water (80 mmol). The pH of the system at this point was 11.2. When this mixture was reacted under reflux conditions for 20 hours, 607.5 mL (41% yield) of hydrogen was generated. Here, methanol (8.2 mmol) corresponding to consumption and water (8.2 mmol) were added to the reaction system, and sodium hydroxide (0.5 mol%) was added again to bring the pH in the system to 11.3. After the adjustment, when reacted for 20 hours under reflux conditions, 611.3 mL (41% yield) of hydrogen was generated. By repeating the same operation again, 562.5 mL (yield 38%) of hydrogen could be obtained.
A total of 1781.3 mL (71.5 mmol) of hydrogen could be obtained by such a continuous hydrogen generation method, and 1191 times as the catalyst rotation speed was achieved. It is possible to develop a new system capable of continuously generating hydrogen gas by using a safe and easy-to-handle raw material for the catalyst (a mixture of methanol and water) and a procedure in which sodium hydroxide is continuously added and heated.

[Example 36]
<Method for generating hydrogen from methanol and water (continuous addition method 1)>

In order to make up for methanol and water consumed with catalytic hydrogen generation, an experiment was conducted in which a syringe pump was added at a constant pace.
First, catalyst 3 (0.1 mol%) and sodium hydroxide (0.5 mol%) were added to a mixture of methanol (20 mmol) and water (80 mmol). The pH of the system at this point was 11.2. The reaction system is heated to start refluxing, and [methanol (0.6 mmol / h), water (0.6 mmol / h), sodium hydroxide (0.001 mmol / h)] is previously added using a syringe pump. These were added as a mixed solution. By continuing the reflux, gas generation was observed at a substantially constant pace. After 50 hours, 2385 mL of hydrogen (99.61 mmol) could be obtained, and a catalyst rotation speed of 1660 was achieved.
In this way, by continuously reacting the consumed raw materials (methanol and water) and sodium hydroxide in an amount corresponding to the consumption rate, hydrogen gas is maintained at a substantially constant pace for a long time (50 hours). Can be generated automatically.

[Example 37]
<Method for generating hydrogen from methanol and water (continuous addition method 2)>

In order to make up for methanol and water consumed with catalytic hydrogen generation, an experiment in which addition was performed at a constant pace using a syringe pump was similarly extended to 150 hours.
First, catalyst 3 (0.1 mol%) and sodium hydroxide (0.5 mol%) were added to a mixture of methanol (20 mmol) and water (80 mmol). The pH of the system at this point was 11.2. The reaction system is heated to start refluxing, and [methanol (0.6 mmol / h), water (0.6 mmol / h), sodium hydroxide (0.001 mmol / h)] is previously added using a syringe pump. As a mixed solution. By continuing the reflux, gas generation was observed at a substantially constant pace. After 150 hours, 4946 mL of hydrogen (210.2 mmol) could be obtained, and the catalyst rotation speed was 3502 times.
In this way, by continuously reacting the consumed raw materials (methanol and water) and sodium hydroxide in an amount corresponding to the consumption rate, hydrogen gas is maintained at a substantially constant pace for a long time (150 hours). Can be generated automatically.

[Example 38]
<Dehydrogenative carboxylic acid synthesis reaction using lower alcohol and water as raw materials>
Using a mixture of a lower alcohol (ethanol, 1-propanol, 1-butanol) and water as a raw material, a catalytic reaction for obtaining hydrogen and at the same time obtaining a carboxylic acid having a corresponding carbon number was studied. First, an anionic catalyst 3 (3.0 mol%) and sodium hydroxide (3.0 mol%) were added to a mixture of ethanol (10 mmol) and water (20 mmol) and reacted for 20 hours under reflux conditions. Was produced in a yield of 85%, and 445 mL (yield 92%) of hydrogen was obtained (entry 1). Further, when a similar reaction using a mixture of 1-propanol and water as a raw material was carried out for 40 hours, propionic acid was obtained in a yield of 68% and 411 mL (yield: 85%) of hydrogen was generated. In this reaction, a small amount (18%) of an ester product (propyl propionate) was also observed (entry 2). Furthermore, a similar carboxylic acid production reaction proceeded by a reaction using a mixture of 1-butanol and water as raw materials, and butyric acid could be obtained with generation of hydrogen (entries 3 and 4).

Claims (16)

Formula (1)
Where
Ar is 1,2-dimethylcyclopentadienyl group, 1,3-dimethylcyclopentadienyl group, 1,2,3-trimethylcyclopentadienyl group, 1,2,4-trimethylcyclopentadienyl group 1,2,3,4-tetramethylcyclopentadienyl group or 1,2,3,4,5-pentamethylcyclopentadienyl group ,
M is iridium,
R ¹ to R ⁶ are, independently of one another, a hydrogen atom, nitro group, cyano group, hydroxy group, mosquitoes carboxyl group, one or more hydrogen atoms may be substituted, an alkyl group of C1~10 , a cycloalkyl group of C3-15, aryl group C6～15, heterocyclyl group C1-10, alkoxy groups of C 1 to 10, ester groups C1-10, fluoroalkyl group C1-10, C 1 to 10 A sulfonyl group, a C1-10 amino group or a C1-10 amide group,
R ³ and R ⁴ may be linked together to form —CH═CH— ,
L is an acoligand,
An organometallic compound represented by   A dehydrogenation catalyst comprising the organometallic compound according to claim 1.   A method for dehydrogenating alcohol, formic acid or formate using a catalyst comprising the organometallic compound according to claim 1.   A method for producing a carbonyl compound, comprising using the dehydrogenation method according to claim 3 to produce a corresponding carbonyl compound by dehydrogenation of an alcohol.   The method according to claim 4, wherein the carbonyl compound is a ketone or an aldehyde.   The method according to claim 4, wherein the alcohol is a primary alcohol, the carbonyl compound is a carboxylic acid, and a solvent containing water is used.   A method for producing hydrogen, comprising using the dehydrogenation method according to claim 3 to produce hydrogen by dehydrogenation of alcohol, a mixture containing alcohol and water, formic acid or formate. Formula (2)
Where
Ar is 1,2-dimethylcyclopentadienyl group, 1,3-dimethylcyclopentadienyl group, 1,2,3-trimethylcyclopentadienyl group, 1,2,4-trimethylcyclopentadienyl group 1,2,3,4-tetramethylcyclopentadienyl group or 1,2,3,4,5-pentamethylcyclopentadienyl group ,
M is iridium,
R ¹ to R ⁶ are, independently of one another, a hydrogen atom, nitro group, cyano group, hydroxy group, mosquitoes carboxyl group, one or more hydrogen atoms may be substituted, an alkyl group of C1~10 , a cycloalkyl group of C3-15, aryl group C6～15, heterocyclyl group C1-10, alkoxy groups of C 1 to 10, ester groups C1-10, fluoroalkyl group C1-10, C 1 to 10 A sulfonyl group, a C1-10 amino group or a C1-10 amide group ,
R ³ and R ⁴ may be linked together to form —CH═CH— ,
Z is Na, Li, K or Cs.
An organometallic compound represented by   A method for dehydrogenating an alcohol, formic acid or formate using a catalyst comprising the organometallic compound according to claim 8.   A dehydrogenation catalyst comprising the organometallic compound according to claim 8.   A method for producing a carbonyl compound, comprising using the dehydrogenation method according to claim 9 to produce a corresponding carbonyl compound by dehydrogenation of an alcohol.   The method according to claim 11, wherein the carbonyl compound is a ketone or an aldehyde.   The method according to claim 11, wherein the alcohol is a primary alcohol, the carbonyl compound is a carboxylic acid, and a solvent containing water is used.   A method for producing hydrogen, comprising using the dehydrogenation method according to claim 9 to dehydrogenate alcohol, a mixture containing alcohol and water, formic acid or formate.   A method for continuously producing hydrogen, wherein an alkali compound is added to a mixture containing alcohol and water, and the general formula (1) according to claim 1 and / or the general formula (2) according to claim 8. The method, wherein the dehydrogenation reaction is carried out in the presence of the organometallic compound represented by the formula, and the mixture and the alkali compound are added one or more times during the course of dehydrogenation. A system for continuously producing hydrogen using the method according to claim 15, comprising a reaction tank for performing a dehydrogenation reaction, a supply unit for supplying a mixture containing an alcohol and water and an alkali compound, and the produced hydrogen. The system including a recovery unit for recovery.