Catalyst for hydroxycarbonylation of alkenes, metal complex, and method for producing carboxylic acid compounds

Abstract

To provide a catalyst for hydroxycarbonylation of an alkene, a metal complex, and a method for producing a carboxylic acid compound, which enable efficient production of a carboxylic acid compound by a simpler method than before without using a compound susceptible to lose activity in air and a compound having high toxicity.SOLUTION: Provided is a catalyst for hydroxycarbonylation of an alkene, represented by formula (1a): MHkXlL1mL2n (1a). In the formula, M represents at least one metal atom selected from the group consisting of atoms of Periodic Table Group 8-12 and chromium atom; X represents a halogen atom; L1 represents a ligand comprising an atom of Periodic Table Group 14-16; L2 represents a ligand comprising at least one atom selected from the group consisting of nitrogen atom and phosphorus atom; k represents a number of 1 or 2; l represents a number of 1-3; m represents a number of 0-5; and n represents a number of 1-6).SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention relates to a catalyst for the hydroxycarbonylation of alkenes, a metal complex, and a method for producing carboxylic acid compounds. More specifically, it relates to a catalyst for the hydroxycarbonylation of alkenes, a metal complex, and a method for producing carboxylic acid compounds that can be used as raw materials for various industrial products and household goods. [Background technology]

[0002] Carboxylic acids and carboxylic acid esters are compounds widely used as raw materials for various industrial products and everyday goods. In recent years, the development of technologies that utilize carbon dioxide as a C1 carbon raw material and convert it into useful chemicals has become important not only from the perspective of reducing environmental impact but also from the perspective of effectively utilizing underutilized resources, and the production of carboxylic acids and carboxylic acid esters using carbon dioxide as a raw material has also been reported. For example, the hydroxycarbonylation of alkenes using Rh complex catalysts has been reported, and it has been reported that various aliphatic carboxylic acids can be synthesized in high yield from CO2 / H2 and alkenes using this reaction (see Non-Patent Literature 1). In addition, it has been reported that the hydroxycarbonylation of alkenes proceeds efficiently in the presence of an Rh complex catalyst when formic acid, obtained by reacting carbon dioxide and hydrogen, is used as a carbonylating agent (see Non-Patent Literature 2). Generally, in the production of carboxylic acids from alkenes, technologies using CO2 / H2 mixed gas or CO / H2O mixed gas have been considered. However, using formic acid as a carbonylating agent is considered an industrially important reaction not only from the perspective of reducing environmental impact but also from the perspective of manufacturing process safety, because it does not require high pressure in the reaction conditions and does not use flammable gas H2 or flammable and toxic gas CO. In addition to Non-Patent Document 2, other reactions for producing carboxylic acids, their salts, or esters from alkenes and formic acid have been reported (see Patent Documents 1-3 and Non-Patent Document 3). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2016-132634 [Patent Document 2] International Publication No. 04 / 076397 [Patent Document 3] International Publication No. 11 / 048851 [Non-patent literature]

[0004] [Non-Patent Document 1] "Angewante Chemie International Edition," 2013, Volume 52, pp. 12119-12123. [Non-Patent Document 2] Journal of Molecular Catalysis A, 2003, Vol. 197, pp. 61-64. [Non-Patent Document 3] Journal of CO2 Utilization, 2018, Vol. 25, pp. 1-5 [Overview of the project] [Problems that the invention aims to solve]

[0005] As described above, various reactions have been reported to produce carboxylic acids, their salts, or esters using carbon dioxide or formic acid as raw materials. However, in the methods described in Non-Patent Documents 1-3, the addition of large amounts of reaction accelerators such as triphenylphosphine and methyl iodide to the Rh catalyst is essential. Triphenylphosphine is easily oxidized in air and inactivated by the formation of triphenylphosphine oxide, so care must be taken when handling it. Methyl iodide is highly irritating and toxic, resulting in a high environmental burden, and is also highly corrosive, requiring expensive materials such as Hastelloy or Inconel for reactors and other components. For these reasons, a highly efficient manufacturing process using the methods described in Non-Patent Documents 1-3 has not yet been established. Furthermore, in the method described in Patent Document 1, the actual product obtained is a carboxylic acid salt, so in order to produce a carboxylic acid, a step of neutralization with acid to convert it to a carboxylic acid and extraction is necessary. In the method described in Patent Document 2, an additional post-treatment step is required to deactivate the excess oxidizing agent with a reducing agent such as sodium thiosulfate, and the reaction time is long. The method described in Patent Document 3 requires the use of three types of compounds as catalysts: a Ru compound, a Co compound, and a halide salt, making the manufacturing process complicated. Thus, none of the current manufacturing methods are considered sufficient.

[0006] This invention has been made in view of the above-mentioned circumstances, and aims to provide a catalyst for the hydroxycarbonylation of alkenes, a metal complex, and a method for producing carboxylic acid compounds that can efficiently produce carboxylic acid compounds (carboxylic acids and / or carboxylic acid esters) in a simpler manner than conventional methods, without using compounds that are easily deactivated in air or highly toxic compounds. [Means for solving the problem]

[0007] The present inventors studied a method for efficiently producing carboxylic acid compounds in a simpler manner than conventional methods without using compounds that are easily deactivated in air or highly toxic compounds. As a result, they found that the roles played by each reaction accelerator that had been added in excess in the methods of Non-Patent Documents 1 to 3 were in stabilizing the catalyst, activating the catalyst, and generating reaction intermediates. Similarly, they found that one of the roles played by acidic additives such as pTSA·H2O, which are also essential for addition, was in generating hydride species for catalytic activity. By using a catalyst containing a component having these functions as a ligand in its structure, even without substantially using reaction accelerators that had problems such as deactivation in air and toxicity in the past, when an alkene is reacted with formic acid and / or a formate ester, carbon dioxide and hydrogen, or carbon monoxide and water to obtain a carboxylic acid compound, hydroxycarbonylation of the alkene proceeds extremely efficiently, and the present invention has been completed.

[0008] That is, the present invention relates to a catalyst for hydroxycarbonylation of an alkene represented by the formula (1a): MH 2 X l L 1 m L 2 n (1a) (In the formula, M represents at least one metal atom selected from the group consisting of atoms of Groups 8 to 12 of the periodic table and a chromium atom. X represents a halogen atom. L 1 represents a ligand containing an atom of Groups 14 to 16 of the periodic table. L 2 represents a ligand containing at least one atom selected from the group consisting of a nitrogen atom and a phosphorus atom. k represents a number of 1 or 2. l represents a number of 1 to 3. m represents a number of 0 to 5. n represents a number of 1 to 6.) and is characterized by being a catalyst for hydroxycarbonylation of an alkene.

[0009] The present invention also relates to a compound represented by the formula (1b): MH k X l L 1 m L 2 n (1b) (In the formula, M represents at least one metal atom selected from the group consisting of atoms from groups 8 to 12 of the periodic table and chromium atoms. X represents a halogen atom. L) 1 L represents a ligand containing atoms from groups 14-16 of the periodic table. 2 L represents a ligand containing at least one atom selected from the group consisting of nitrogen atoms and phosphorus atoms. 2 If it contains a phosphorus atom, the phosphorus atom has a substituent with 3 or more carbon atoms. k represents a number of 1 or 2. l represents a number from 1 to 3. m represents a number from 0 to 5. n represents a number from 1 to 6. This is a metal complex characterized by being represented by [the formula shown].

[0010] The present invention also includes formula (2):

[0011] [ka]

[0012] (In the formula, R 1 and R 2 R represents a hydrogen atom or an organic group with 1 to 24 carbon atoms, either identical or different. 1 and R 2 And may be linked together. From an alkene represented by ), equation (3):

[0013] [ka]

[0014] (In the formula, R 1 and R 2 This is the same as equation (2). R 3 A method for producing a carboxylic acid compound represented by ) where represents a hydrogen atom or an organic group having 1 to 24 carbon atoms, The above manufacturing method is also a method for producing a carboxylic acid compound, characterized by including a step of reacting an alkene represented by formula (2) with formic acid and / or a formic acid ester, carbon dioxide and hydrogen, or carbon monoxide and water in the presence of the catalyst described above.

[0015] In the method for producing the above carboxylic acid compound, the amount of catalyst used is preferably 0.001 to 1 mole per mole of the alkene represented by formula (2).

[0016] In the method for producing the carboxylic acid compound described above, the reaction step is carried out in the presence of a solvent, and it is preferable that the solvent includes at least one selected from the group consisting of water, aromatic hydrocarbons, aliphatic hydrocarbons, and carboxylic acids. [Effects of the Invention]

[0017] The catalyst for hydroxycarbonylation of alkenes, the metal complex, and the method for producing carboxylic acid compounds of the present invention can be conveniently used as a method for producing carboxylic acid compounds that can be used in a variety of applications, because they do not require the use of compounds that are easily deactivated in air or highly toxic as reaction accelerators. [Modes for carrying out the invention]

[0018] The present invention will be described in detail below. Furthermore, combinations of two or more of the individual preferred embodiments of the present invention described below are also preferred embodiments of the present invention. In this specification, "carboxylic acid compound" means "carboxylic acid and / or carboxylic acid ester."

[0019] 1. Catalyst for hydroxycarbonylation of alkenes The catalyst for hydroxycarbonylation of alkenes of the present invention is of formula (1a): MH k X l L 1 m L 2 n (1a) (In the formula, M represents at least one metal atom selected from the group consisting of atoms from groups 8 to 12 of the periodic table and chromium atoms. X represents a halogen atom. L) 1L represents a ligand containing atoms from groups 14-16 of the periodic table. 2 This is characterized by being represented as follows: represents a ligand containing at least one atom selected from the group consisting of nitrogen atoms and phosphorus atoms. k represents a number of 1 or 2. l represents a number of 1 to 3. m represents a number of 0 to 5. n represents a number of 1 to 6.

[0020] The catalyst of the present invention allows for the efficient production of carboxylic acid compounds without the use of compounds that are easily deactivated in air or highly toxic compounds. Since the catalyst of the present invention is composed of a hydride and ligands of components having various functions such as catalyst stabilization, catalyst activation, and generation of reaction intermediates, carboxylic acid compounds can be efficiently produced by using the catalyst in the reaction of alkenes with formic acid and / or formic acid esters, carbon dioxide and hydrogen, or carbon monoxide and water. Furthermore, in the production of carboxylic acid compounds, conventional methods have required the separate addition of excess compounds with the above functions as reaction accelerators. However, since the catalyst of the present invention incorporates these compounds as ligands into the catalyst structure, there is no deactivation of reaction accelerator components in air or leakage of highly toxic components that occurred in conventional production methods. Moreover, the hydroxycarbonylation of alkenes can be carried out without essentially adding any reaction accelerators.

[0021] In formula (1a) above, M represents at least one metal atom selected from the group consisting of atoms from groups 8 to 12 of the periodic table and chromium atoms. Among the atoms from groups 8 to 12 of the periodic table and chromium atoms, atoms from groups 8 to 10 of the periodic table are preferred in terms of ease of catalyst synthesis and structural stability of the catalyst, Fe, Ru, Co, Rh, and Ir are more preferred, Co, Rh, and Ir are even more preferred, and Rh and Ir are particularly preferred.

[0022] In the above formula (1a), X represents a halogen atom. Examples of halogen atoms represented by X include fluorine, chlorine, bromine, and iodine. Among these, bromine and iodine are preferred, and iodine is more preferred, in terms of efficiently promoting the hydroxycarbonylation of alkenes. The catalyst represented by the above formula (1a) may have only one halogen atom or may have two or more halogen atoms.

[0023] In the above formula (1a), L 1 This represents a ligand containing atoms from groups 14-16 of the periodic table. The above L 1 The ligand preferably consists of at least one atom selected from the group comprising carbon atoms, nitrogen atoms, phosphorus atoms, arsenic atoms, oxygen atoms, and sulfur atoms. More preferably, it consists of carbon atoms, nitrogen atoms, phosphorus atoms, oxygen atoms, and sulfur atoms, and even more preferably, carbon atoms, phosphorus atoms, and oxygen atoms.

[0024] The ligands containing atoms from groups 14 to 16 of the periodic table are preferably selected from carbon monoxide, carboxylic acids, acetylacetone, alkene compounds, amine compounds, imine compounds, phosphine compounds, N-heterocyclic carbene compounds, nitrile compounds, isocyanide compounds, and hydroxyl groups.

[0025] Examples of carboxylic acids include formic acid, acetic acid, and propionic acid, which have 1 to 30 carbon atoms. Examples of alkene compounds include alkenes with 2 to 30 carbon atoms, such as ethylene, propylene, and cyclooctene; and alkadienes with 4 to 30 carbon atoms, such as butadiene, cyclopentadiene, and 1,5-cyclooctadiene. Examples of amine compounds include ammonia; (mono, di, tri)alkylamines with 1 to 30 carbon atoms, such as methylamine, dimethylamine, and trimethylamine; (mono, di, tri)arylamines with 1 to 30 carbon atoms, such as phenylamine, diphenylamine, and triphenylamine; and diamines with 1 to 10 carbon atoms, such as ethylenediamine, propylenediamine, and butane-1,4-diamine. Examples of imine compounds include pyridine; diimines such as 2,2'-bipyridine, 1,10-phenanthroline, and 1,8-naphthyridine. Examples of phosphine compounds include trialkylphosphines with 1 to 24 carbon atoms, such as trimethylphosphine; triarylphosphines with 1 to 24 carbon atoms, such as triphenylphosphine; aralkylphosphines, such as tripenzylphosphine; and diphosphines such as 1,2-bis(diphenylphosphino)ethane, 1,3-bis(diphenylphosphino)propane, 1,4-bis(diphenylphosphino)butane, 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl, and bis[2-(diphenylphosphino)phenyl]ether. Examples of N-heterocyclic carbene compounds include 1,3-di-tert-butylimidazole-2-ylidene, 1,3-bis(2,6-diisopropylphenyl)imidazole-2-ylidene, 1,3-dimethylimidazole-2-ylidene, and 1,3-bis(2,6-diisopropylphenyl)imidazolidine-2-ylidene, which are N-heterocyclic carbene compounds with 3 to 30 carbon atoms derived from imidazolium salts. Examples of nitrile compounds include alkanes, alkenes, and alkynes with 1 to 24 carbon atoms, as well as aromatic hydrocarbons such as benzene and naphthalene, in which hydrogen atoms are replaced with -CN. Examples of isocyanide compounds include alkanes, alkenes, and alkynes with 1 to 24 carbon atoms, as well as aromatic hydrocarbons such as benzene and naphthalene, in which hydrogen atoms are replaced with -NC atoms.

[0026] In particular, ligand L 1 It is preferably carbon monoxide, a carboxylic acid, or an alkene compound.

[0027] In the above formula (1a), L 2 This represents a ligand containing at least one atom selected from the group consisting of nitrogen atoms and phosphorus atoms. Ligand L 2 It is sufficient if it contains at least a nitrogen atom or a phosphorus atom, but may also contain other atoms.

[0028] Ligand L containing at least a nitrogen atom or a phosphorus atom 2 Specifically, preferred examples include amine compounds, imine compounds, phosphine compounds, nitrile compounds, and isocyanide compounds. Specific examples of these compounds are the same as those mentioned above. In particular, ligand L is effective in efficiently carrying out the hydroxycarbonylation of alkenes. 2 The compound is preferably an amine compound, an imine compound, or a phosphine compound, more preferably a phosphine compound, even more preferably an arylphosphine, an aralkylphosphine, or a diphosphine, and particularly preferably a triarylphosphine.

[0029] Ligand L 1 and L 2 These may be the same as long as they satisfy the above conditions, but it is preferable that they be different.

[0030] Ligand L 1 and L 2 Depending on the number of coordination sites, it may be a monodentate ligand, a didentate ligand, or a polydentate ligand with two or more locations, preferably a monodentate ligand or a didentate ligand, and more preferably a monodentate ligand.

[0031] The catalyst compound represented by the above formula (1a) includes X, L 1 and L 2 This also includes binuclear metal complexes bridged via at least one of the following.

[0032] Of the metal complexes in formula (1a) above, L 2 When a phosphorus atom is present, any metal complex in which the phosphorus atom has substituents with 3 or more carbon atoms is a novel metal complex. This novel metal complex is, i.e., formula (1b): MH k X l L 1 m L 2 n (1b) (In the formula, M represents at least one metal atom selected from the group consisting of atoms from groups 8 to 12 of the periodic table and chromium atoms. X represents a halogen atom. L) 1 L represents a ligand containing atoms from groups 14-16 of the periodic table. 2 L represents a ligand containing at least one atom selected from the group consisting of nitrogen atoms and phosphorus atoms. 2 If it contains a phosphorus atom, the phosphorus atom has a substituent with 3 or more carbon atoms. k represents a number of 1 or 2. l represents a number from 1 to 3. m represents a number from 0 to 5. n represents a number from 1 to 6. A metal complex represented by ( is also one of the present inventions.

[0033] The substituents having 3 or more carbon atoms on the phosphorus atom are not particularly limited, but examples include alkyl groups, aryl groups, and aralkyl groups having 3 or more carbon atoms. Furthermore, the phosphorus atom preferably has one or more substituents having 3 or more carbon atoms, and more preferably has two or more substituents.

[0034] 2. Method for producing a catalyst for the hydroxycarbonylation of alkenes The method for producing the catalyst of the present invention represented by formula (1a) above is not particularly limited as long as a predetermined compound can be obtained, but examples include introducing a hydride ligand to a metal halide and introducing a halogen ligand to a metal hydride (hydride compound). Methods for introducing a hydride ligand to a metal halide include reacting the metal halide with a hydride compound such as NaBH4 or LiAlH4, reacting the metal halide with an alkoxide such as iso-PrOK, reacting the metal halide with an alkoxide such as iso-PrOK to synthesize an alkoxide complex and then reacting it with a hydrogen molecule, reacting the metal halide with a protic compound such as a hydrogen halide, and reacting the metal halide with a hydrogen molecule. Methods for introducing a halogen ligand to a metal hydride (hydride compound) include reacting the metal hydride with a protic compound such as a hydrogen halide and reacting the metal hydride with a halogen. In terms of ease of catalyst production, high production efficiency, and safety during production, methods involving the reaction of a metal halide with a protic compound such as a hydrogen halide, or a metal hydride with a protic compound such as a hydrogen halide are preferred, and methods involving the reaction of a metal halide with a protic compound such as a hydrogen halide are more preferred. For example, such a production method is given by formula (a): MX' l L 1 m L 2 n (a) (In the formula, M, L 1 , L 2 A preferred method includes the step of reacting a metal complex represented by (1a) with a hydrogen halide or hydrohalic acid (an aqueous solution of hydrogen halide) in a solvent.

[0035] When l is 2 in equation (a), the two halogen atoms may be the same or different. When producing a catalyst represented by formula (1a) containing only one type of halogen atom, it is sufficient to use a metal complex represented by formula (a) that contains only one type of halogen atom, and furthermore, to use a hydrogen halide that reacts with the metal complex that also contains the same halogen atom. When producing a catalyst represented by formula (1a) containing two or more halogen atoms, one can use either a method in which a metal complex represented by formula (a) contains two types of halogen atoms, or a method in which hydrogen halide contains halogen atoms different from those of the metal complex represented by formula (a), or both.

[0036] The amount of hydrogen halide used is not particularly limited as long as the desired compound can be obtained. When the reaction is carried out under insufficient conditions relative to 1 mole of metal atoms in the metal complex, the unreacted metal complex represented by formula (a) can be removed. When the reaction is carried out under excess conditions, the unreacted hydrogen halide and by-products can be removed by appropriate purification. In terms of ease of catalyst production and efficient production of the desired compound, the amount of hydrogen halide used is preferably in excess conditions relative to 1 mole of metal atoms in the metal complex represented by formula (a), more preferably 1.0 to 20 moles, even more preferably 1.0 to 10 moles, and particularly preferably 1.0 to 5.0 moles.

[0037] The above reaction is preferably carried out in a solvent. Examples of the solvents mentioned above include alcohols such as methyl alcohol, ethyl alcohol, and isopropyl alcohol; ketone compounds such as acetone and methyl ethyl ketone; aromatic or aliphatic hydrocarbons such as benzene, toluene, xylene, cyclohexane, n-hexane, n-decane, n-undecane, and n-tridecane; carboxylic acids such as acetic acid, difluoroacetic acid, trifluoroacetic acid, propionic acid, butanoic acid, pentanoic acid, and hexanoic acid; ester compounds such as ethyl acetate; cyclic ether compounds such as tetrahydrofuran and dioxane; linear ether compounds such as dibutyl ether and diisopropyl ether; halogenated hydrocarbons such as dichloromethane, chloroform, carbon tetrachloride, 1,2-dichloroethane, 1,1,1-trichloroethane, 1,1,2,2-tetrachloroethane, 1,2-dichloroethylene, trichloroethylene, and tetrachloroethylene. Among these, ketone compounds, aromatic or aliphatic hydrocarbons, and halogenated hydrocarbons are preferred in terms of the high solubility of the metal complex represented by formula (a) above.

[0038] The conditions for the above reaction are not particularly limited as long as the desired compound is obtained, but for example, the reaction temperature can be set appropriately according to the reaction solvent used, and it is preferable to carry out the reaction below the boiling point of the solvent, more preferably between room temperature and 150°C, even more preferably between room temperature and 100°C, and particularly preferably between room temperature and 80°C. The reaction time is preferably 0.5 to 72 hours, more preferably 0.5 to 48 hours, and even more preferably 0.5 to 30 hours.

[0039] After the above reaction steps, known steps that are normally performed, such as concentration steps, purification steps, washing steps, and drying steps, may be carried out. The above concentration method is not particularly limited, and known methods can be used, such as heating under reduced pressure. The heating temperature is preferably room temperature to 150°C, more preferably room temperature to 100°C, and even more preferably room temperature to 80°C, in order to maintain the structure of the prepared product without damaging it. The pressure is preferably set to the pressure necessary to sufficiently remove the reaction solvent used at the above heating temperature, and is set appropriately depending on the solvent.

[0040] The purification method described above is not particularly limited and includes known methods such as filtration, extraction, recrystallization, and distillation. The above drying process is not particularly limited as long as the reaction solvent used can be sufficiently removed, but drying under reduced pressure is preferable in that it can maintain the structure of the manufactured product without damaging it, and a heating method at room temperature to 150°C, more preferably room temperature to 100°C, and even more preferably room temperature to 80°C is recommended.

[0041] In the production of the catalyst of the present invention represented by formula (1a) above, before the step of reacting the metal complex represented by formula (a) above with hydrogen halide in a solvent, a step may be performed to obtain the metal complex represented by formula (a) above by replacing the halogen atom contained in the metal complex with another halogen atom, if necessary. One method for obtaining a metal complex represented by formula (a) above by replacing a halogen atom in the metal complex with another halogen atom is to include, for example, a step of reacting a metal complex represented by formula (a') below with an alkali metal halide containing the same halogen atom as X' in formula (a). Formula (a'):MX'' l L 1 m L 2 n (a') (In the formula, M, L 1 , L 2 m and n are the same as in formula (1a). At least one of X'' represents a halogen atom different from X' in formula (a). l represents a number of 1 or 2. A commercially available metal complex may be used as the metal complex represented by the above formula (a').

[0042] The amount of alkali metal halide used is not particularly limited as long as the desired compound can be obtained. When the reaction is carried out under conditions of insufficient alkali metal halide per mole of metal atoms in the metal complex, the unreacted metal complex represented by formula (a') can be removed. When the reaction is carried out under conditions of excess alkali metal halide per mole of metal atoms in the metal complex, the unreacted alkali metal halide and by-products can be removed by appropriate purification. In terms of ease of catalyst production and efficient production of the desired compound, the amount of alkali metal halide used is preferably in excess per mole of metal atoms in the metal complex represented by formula (a'), more preferably 1.0 to 30 moles, even more preferably 1.0 to 25 moles, and particularly preferably 1.0 to 20 moles.

[0043] The reaction between the metal complex represented by formula (a') above and the alkali metal halide is preferably carried out in a solvent, and the solvent is preferably the same as the reaction solvent described above.

[0044] The reaction conditions between the metal complex represented by formula (a') and the alkali metal halide are not particularly limited, but the reaction temperature can be set appropriately according to the reaction solvent used, and is preferably below the boiling point of the solvent, more preferably between room temperature and 150°C, even more preferably between room temperature and 100°C, and particularly preferably between room temperature and 80°C. The reaction time is preferably 0.5 to 72 hours, more preferably 0.5 to 48 hours, and even more preferably 0.5 to 30 hours.

[0045] After the above reaction step, known steps that are normally performed, such as the concentration step, purification step, washing step, and drying step described above, may be carried out.

[0046] The compound represented by formula (1a) above is suitably used as a catalyst for the hydroxycarbonylation of alkenes. Using the compound represented by formula (1a) as a catalyst for the hydroxycarbonylation of alkenes allows for the efficient production of carboxylic acid compounds without the need for compounds that are easily deactivated in air or highly toxic. Furthermore, the elimination of toxicity issues reduces environmental impact. Additionally, the use of common organic solvents expands the range of applications for hydroxycarbonylation. Moreover, when an acidic solvent is selected, it eliminates the need to add even pTSA·H2O, an acidic additive that was essential in conventional techniques, resulting in a highly efficient (additive-free) production process that does not require reaction accelerators or acidic additives. Thus, using the catalyst of the present invention represented by formula (1a) above facilitates reactions in simple catalyst systems, making it easier to design more efficient chemical production methods, such as flow synthesis methods for carboxylic acid compounds.

[0047] 3. Method for producing carboxylic acid compounds The present invention also includes formula (2):

[0048] [ka] (In the formula, R 1 and R 2 R represents a hydrogen atom or an organic group with 1 to 24 carbon atoms, either identical or different. 1 and R 2 And may be linked together. From an alkene represented by ), equation (3):

[0049] [ka]

[0050] (In the formula, R 1 and R 2 This is the same as equation (2). R 3 A method for producing a carboxylic acid compound represented by ) where represents a hydrogen atom or an organic group having 1 to 24 carbon atoms, The above manufacturing method is a method for producing a carboxylic acid compound, characterized by comprising the step of reacting an alkene represented by formula (2) with formic acid and / or a formic acid ester, carbon dioxide and hydrogen, or carbon monoxide and water in the presence of the catalyst described above. The catalyst mentioned above is the "catalyst for hydroxycarbonylation of alkenes" described above.

[0051] The manufacturing method of the present invention allows for the efficient production of carboxylic acid compounds to approximately the same extent as conventional methods using reaction accelerators such as triphenylphosphine and methyl iodide, without the need for such accelerators. Because the manufacturing method of the present invention allows for the efficient production of carboxylic acid compounds without the use of these reaction accelerators, problems of toxicity and corrosiveness can be reduced, and it becomes possible to produce carboxylic acid compounds while lowering environmental impact and equipment costs.

[0052] The present invention provides a method for producing carboxylic acids, which involves reacting an alkene represented by formula (2) with any of the following: (i) formic acid and / or a formic acid ester, (ii) carbon dioxide and hydrogen, or (iii) carbon monoxide and water. However, it may also involve reacting two or more of these substances. In this invention, "metal" includes "precious metals."

[0053] In equation (2) above, R 1 , R 2 R represents a hydrogen atom or an organic group with 1 to 24 carbon atoms, either identical or different. 1 and R 2 They may be connected. R 1 , R 2 If the organic group is a monovalent organic group, the number of carbon atoms in the organic group is preferably 1 to 20, and more preferably 1 to 16.

[0054] R 1 , R 2When is a monovalent organic group, examples of organic groups include alkyl groups, alkenyl groups, alkoxy groups, aryl groups, arylalkyl groups, aryloxy groups, aryloxycarbonyl groups, acyl groups, aroyl groups, alkylsulfonyl groups, arylsulfonyl groups, arylalkylsulfonyl groups, trialkylsilyl groups, dialkylarylsilyl groups, alkyldiarylsilyl groups, triarylsilyl groups, bis(dialkylamino)phosphinoyl groups, dialkylphosphinoyl groups, diarylphosphinoyl groups, dialkylphosphonyl groups, diarylphosphonyl groups, and the like. Among these, any of alkyl groups, alkenyl groups, aryl groups, alkoxycarbonyl groups, aryloxycarbonyl groups, acyl groups, aroyl groups, alkylsulfonyl groups, arylsulfonyl groups, arylalkylsulfonyl groups, bis(dialkylamino)phosphinoyl groups, dialkylphosphinoyl groups, diarylphosphinoyl groups, dialkylphosphonyl groups, or diarylphosphonyl groups are preferred.

[0055] The above R 1 , R 2 The organic groups listed as specific examples may all have one or more hydrogen atoms substituted with substituents. Examples of substituents include alkyl groups, aryl groups, alkenyl groups, alkoxy groups, aryloxy groups, alkoxycarbonyl groups, aryloxycarbonyl groups, acyl groups, aroyl groups, alkylsulfonyl groups, arylsulfonyl groups, arylalkylsulfonyl groups, trialkylsilyl groups, dialkylarylsilyl groups, triarylsilyl groups, bis(dialkylamino)phosphinoyl groups, dialkylphosphinoyl groups, diarylphosphinoyl groups, dialkylphosphonyl groups, diarylphosphonyl groups, carboxyl groups, sulfonyl groups, amino groups, silyl groups, chloro groups, fluoro groups, trifluoromethyl groups, 4-pyridyl groups, 3-pyridyl groups, and 2-pyridyl groups. The number of carbon atoms in the substituent is not particularly limited; the total number of carbon atoms in the organic group, including the substituent, should be between 1 and 24, but it is preferable that the number of carbon atoms be between 0 and 23.

[0056] In the above formula (3), R 1 and R 2 are the same as in formula (2). R 3 represents a hydrogen atom or an organic group having 1 to 24 carbon atoms. Examples of the organic group having 1 to 24 carbon atoms include the same groups as the organic group having 1 to 24 carbon atoms represented by R 1 and R 2 in formula (2). Among them, the organic group having 1 to 24 carbon atoms represented by R 3 is preferably a monovalent organic group, more preferably an alkyl group, an alkenyl group or an aryl group.

[0057] In the above reaction step, when reacting the alkene represented by the above formula (2) with formic acid and / or a formate, the amount of formic acid and / or a formate used is preferably in a ratio of 0.1 to 20 moles per 1 mole of the alkene represented by the above formula (2). More preferably, it is in a ratio of 0.5 to 10 moles per 1 mole of the alkene represented by the above formula (2), and even more preferably, it is in a ratio of 1.0 to 5 moles. The above formate is an esterified product of formic acid and is a compound represented by HCOOR 3 (R 3 is the same as R 3 in formula (3).).

[0058] In the above reaction step, when reacting the alkene represented by the above formula (2) with carbon dioxide and hydrogen, the amount of hydrogen used is preferably in a ratio of 0.1 to 20 moles per 1 mole of the alkene represented by the above formula (2). More preferably, it is in a ratio of 0.5 to 10 moles per 1 mole of the alkene represented by the above formula (2), and even more preferably, it is in a ratio of 1 to 5 moles. )

[0059] While there are no particular restrictions on the amount of carbon dioxide used, in addition to being a reaction raw material, carbon dioxide is a non-flammable gas and therefore also serves as a diluent for safely handling flammable gases such as alkenes and hydrogen gas. Accordingly, the amount of carbon dioxide can be set appropriately from the perspective of both productivity and the safety of the manufacturing process, and may be used in large excess relative to the alkenes or hydrogen gas represented by formula (2) above. However, it is preferable that the ratio is 0.1 to 200 moles per mole of alkene represented by formula (2) above. More preferably, the ratio is 0.5 to 150 moles per mole of alkene represented by formula (2) above, and even more preferably, 1 to 100 moles.

[0060] In the above reaction step, when reacting the alkene represented by formula (2) with carbon monoxide and water, the amount of water used is preferably 0.5 to 20.0 moles per mole of the alkene represented by formula (2), in order to suppress catalyst deactivation. More preferably, the amount of water is 1.0 to 10.0 moles per mole of the alkene represented by formula (2), and even more preferably, 1.0 to 5.0 moles.

[0061] Furthermore, there are no particular restrictions on the amount of carbon monoxide, but from a safety standpoint, for example, it is preferable that the amount is 0.5 to 20.0 moles, more preferably 1.0 to 10.0 moles, and even more preferably 1.0 to 5.0 moles per mole of the alkene represented by formula (2) above.

[0062] In the above reaction step, when the alkene represented by formula (2) is reacted with carbon monoxide and water, water will be present from the beginning of the reaction, which may lead to catalyst deactivation or the generation of by-products due to hydration. Furthermore, carbon monoxide is known to react with nickel, iron, cobalt, etc. to produce metal carbonyls, and this may cause corrosion in equipment using stainless steel containing these metals or corrosion-resistant materials such as Hastelloy and Inconel. Therefore, from the viewpoints of reactivity and safety, the above reaction step is more preferably a step of reacting the alkene represented by the above formula (2) with formic acid and / or a formate, or carbon dioxide and hydrogen.

[0063] The amount of the catalyst used in the method for producing a carboxylic acid of the present invention is not particularly limited as long as the reaction for obtaining the carboxylic acid compound represented by the formula (3) from the alkene represented by the formula (2) proceeds, but it is preferably in a proportion of 0.001 to 1 mol per 1 mol of the alkene represented by the formula (2). By using such a proportion, the carboxylic acid compound can be produced in a higher yield and at a lower production cost. The amount of the catalyst or metal complex used is more preferably 0.005 to 0.5 mol, and even more preferably 0.01 to 0.2 mol, per 1 mol of the alkene represented by the formula (2).

[0064] The method for producing a carboxylic acid compound of the present invention may use a reaction promoter, but the carboxylic acid compound can be efficiently produced without using a reaction promoter. Examples of the above reaction promoter include conventionally known reaction promoters such as triphenylphosphine and methyl iodide. In addition, as the above reaction promoter, a quaternary ammonium salt represented by the formula (4) can be mentioned.

[0065]

Chemical formula

[0066] In the quaternary ammonium salt represented by the above formula (4), R 4 ~R 7 are preferably organic groups having 1 to 30 carbon atoms. More preferably, they are organic groups having 1 to 20 carbon atoms, and even more preferably, they are organic groups having 1 to 10 carbon atoms. R 4 ~R 7Examples of organic groups include alkyl groups, aryl groups, benzyl groups, alkenyl groups, alkoxy groups, aryloxy groups, and alkylene oxides. Among these, alkyl groups, aryl groups, benzyl groups, alkoxy groups, and alkylene oxides are preferred because they are inexpensive and easy to handle, alkyl groups, benzyl groups, and alkylene oxides are more preferred, and alkyl groups are the most preferred.

[0067] In formula (4) above, X represents a halogen atom, and it may be any halogen atom, but fluorine, chlorine, bromine, or iodine are preferred, and among these, iodine is most preferred because it yields a high yield of the resulting carboxylic acid.

[0068] When using the above reaction accelerator, the amount of the reaction accelerator used is not particularly limited as long as the reaction to obtain the carboxylic acid compound represented by formula (3) from the alkene represented by formula (2) proceeds. However, it is preferably 10 moles or less, more preferably 5 moles or less, and even more preferably 1 mole or less, per mole of metal atoms contained in the catalyst. Furthermore, it is preferably 0.05 moles or more, and more preferably 0.2 moles or more, per mole of metal atoms contained in the catalyst.

[0069] The above reaction accelerators may be used individually or in combination of two or more.

[0070] In the method for producing carboxylic acid compounds of the present invention, other additives besides the reaction accelerator described above may be used. Examples of other additives include acidic substances such as p-toluenesulfonic acid (pTSA), p-toluenesulfonic acid (pTSA·H2O) monohydrate, benzenesulfonic acid, benzenesulfonic acid monohydrate, methanesulfonic acid, ethanesulfonic acid, trifluoromethanesulfonic acid, difluoroacetic acid, trifluoroacetic acid, and bis(trifluoromethanesulfonyl)imide, and one or more of these may be used.

[0071] The amount of the above-mentioned other additives used is preferably 0 to 10 moles per mole of the alkene represented by formula (2). More preferably, it is 0 to 5 moles per mole of the alkene represented by formula (2), and even more preferably, it is 0 to 1 mole.

[0072] The step of reacting the alkene represented by formula (2) with formic acid and / or a formic acid ester, carbon dioxide and hydrogen, or carbon monoxide and water may be carried out using a solvent.

[0073] The solvent is not particularly limited as long as the reaction proceeds, but it can be: water; alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol; aromatic or aliphatic hydrocarbons such as benzene, toluene, xylene, cyclohexane, n-hexane, n-decane, n-undecane, n-tridecane; carboxylic acids such as acetic acid, difluoroacetic acid, trifluoroacetic acid, propionic acid, butanoic acid, pentanoic acid, hexanoic acid; ester compounds such as ethyl acetate; ketone compounds such as acetone and methyl ethyl ketone; cyclic ether compounds such as tetrahydrofuran and dioxane; dibutylene Examples include linear ether compounds such as ethers and diisopropyl ether; halogenated hydrocarbons such as dichloromethane, chloroform, carbon tetrachloride, 1,2-dichloroethane, 1,1,1-trichloroethane, 1,1,2,2-tetrachloroethane, 1,2-dichloroethylene, trichloroethylene, and tetrachloroethylene; sulfoxides such as dimethyl sulfoxide; amides such as N,N-dimethylformamide and N-methylpyrrolidone; and ureas such as tetramethylurea and N,N'-dimethylimidazolidinone. One or more of these can be used.

[0074] In particular, when the above reaction step is carried out in the presence of a solvent, the reaction efficiency can be further improved, and therefore, it is preferable that the solvent includes at least one selected from the group consisting of water, aromatic hydrocarbons, aliphatic hydrocarbons, and carboxylic acids. In the production method of the present invention, by using the above catalyst, carboxylic acid compounds can be efficiently produced even when using common organic solvents such as aromatic hydrocarbons and aliphatic hydrocarbons as solvents, thereby expanding the range of applications for hydroxycarbonylation. Furthermore, in the manufacturing method of the present invention, by using the above catalyst, when a carboxylic acid is used as a solvent, carboxylic acid compounds can be efficiently produced without using acidic additives (acidic additives), etc. In the production method of carboxylic acid compounds, acidic substances (acidic additives) play roles such as generating hydride, which is a catalytically active species, or promoting the decomposition of formic acid. However, when a carboxylic acid is used as a solvent, the catalyst and carboxylic acid can perform these roles, so carboxylic acid compounds can be efficiently produced without substantially using acidic substances (acidic additives).

[0075] The reaction temperature in the step of reacting the alkene represented by formula (2) with formic acid and / or a formic acid ester, carbon dioxide and hydrogen, or carbon monoxide and water is not particularly limited as long as the reaction proceeds, but is preferably 100 to 250°C. By carrying out the reaction at such a temperature, the yield of the resulting carboxylic acid can be increased. More preferably, it is 120 to 220°C, and even more preferably, 140 to 200°C.

[0076] Furthermore, the reaction pressure is not particularly limited as long as the reaction proceeds, but it is preferably 0.1 to 50 MPa. More preferably 0.1 to 30 MPa, even more preferably 0.5 to 20 MPa, and most preferably 1.0 to 20 MPa. Furthermore, considering the yield of the carboxylic acid compound and the efficiency of the carboxylic acid compound production, the reaction time is preferably 0.1 to 20 hours. More preferably, it is 0.2 to 15 hours, and even more preferably, 0.5 to 10 hours.

[0077] The method for producing a carboxylic acid compound of the present invention may include other steps, as long as it includes a step of reacting an alkene represented by formula (2) with formic acid and / or a formic acid ester, carbon dioxide and hydrogen, or carbon monoxide and water. For example, the method for producing a carboxylic acid compound of the present invention can be performed in a first step of reacting carbon dioxide and hydrogen to produce formic acid, and then in a second step, the carboxylic acid compound can be produced by reacting the formic acid produced in the first step with an alkene. Alternatively, the carboxylic acid compound can be produced by esterifying the formic acid produced in the first step to obtain a formic acid ester, and then reacting the formic acid ester with an alkene. Other processes include the purification and extraction of the manufactured carboxylic acid compound.

[0078] As described above, the method for producing carboxylic acid compounds of the present invention allows for the efficient production of carboxylic acid compounds in a simpler manner than conventional methods, without using compounds that are easily deactivated in air or highly toxic compounds. [Examples]

[0079] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, "parts" means "parts by mass" and "%" means "percent mass".

[0080] Manufacturing Example 1 Catalyst synthesis All catalyst synthesis was carried out in a glove box under a nitrogen atmosphere. (Synthesis of RhI(CO)(PPh3)2) RhCl(CO)(PPh3)2 (2.00 g, 2.90 mmol), triphenylphosphine (PPh3) (5.00 g, 19.0 mmol), and potassium iodide (6.70 g, 40.0 mmol) were added to acetone (330 g) and mixed at room temperature for 25 hours. The resulting suspension was allowed to stand overnight at room temperature and matured. Subsequently, the suspension was concentrated by evaporating the solvent under conditions of 45°C and 20 kPa while stirring. The resulting concentrated suspension was then separated into solid and liquid by vacuum filtration. The obtained solid was recrystallized at room temperature using benzene in which 1% PPh3 was dissolved and ethanol to obtain a precipitate. The obtained precipitate was separated into solid and liquid by vacuum filtration, and the obtained solid was washed with ethanol while filtering under vacuum. The washed solid was dried under vacuum at room temperature for 15 hours to remove the solvent and obtain RhI(CO)(PPh3)2.

[0081] (Synthesis of RhHI2(CO)(PPh3)2) Next, the RhI(CO)(PPh3)2 (1.00 g, 1.28 mmol) obtained above and 56.4% hydroiodic acid (0.32 g, 0.18 g as HI, 1.41 mmol) were added to acetone (72 g) and mixed at room temperature for 15 hours. After that, the obtained suspension was concentrated by evaporating the solvent under conditions of 30°C and 20 kPa, and the resulting concentrated suspension was separated into solid and liquid by vacuum filtration. The obtained solid was recrystallized at room temperature using dichloromethane and n-hexane to obtain a precipitate. The obtained precipitate was separated into solid and liquid by vacuum filtration, and the obtained solid was washed with n-hexane while filtering under vacuum. The solid after washing was dried under vacuum at 40°C for 15 hours to remove the solvent and obtain RhHI2(CO)(PPh3)2.

[0082] Manufacturing Example 2 Catalyst synthesis All catalyst synthesis was carried out in a glove box under a nitrogen atmosphere. (Synthesis of RhCl(CO)(DPEphos)) [RhCl(CO)2]2 (6.00 g, 15.43 mmol) and bis[2-(diphenylphosphino)phenyl] ether (DPEphos) (17.45 g, 32.41 mmol) were added to toluene (350 g) and mixed at room temperature for 3 hours. The resulting suspension was separated into solid and liquid by vacuum filtration. The obtained solid was then washed by adding fresh toluene (350 g) to the obtained solid and mixing at room temperature for 1 hour, followed by solid and liquid separation of the resulting suspension by vacuum filtration twice. The washed solid was then dried under reduced pressure at 40°C for 15 hours to remove the solvent and obtain RhCl(CO)(DPEphos).

[0083] (Synthesis of RhI(CO)(DPEphos)) Next, the RhCl(CO)(DPEphos) (10.00 g, 14.19 mmol) obtained above and potassium iodide (23.55 g, 141.9 mmol) were added to acetone (600 g) and mixed at room temperature for 15 hours. The resulting suspension was concentrated by evaporating the solvent under conditions of 30°C and 20 kPa while stirring, and the resulting concentrated suspension was separated into solid and liquid by vacuum filtration. The obtained solid was recrystallized at room temperature using dichloromethane and n-hexane to obtain a precipitate. The obtained precipitate was separated into solid and liquid by vacuum filtration, and the obtained solid was washed with n-hexane while filtering under vacuum. The washed solid was dried under vacuum at room temperature for 15 hours to remove the solvent and obtain RhI(CO)(DPEphos).

[0084] (Synthesis of RhHI2(CO)(DPEphos)) Next, the RhI(CO)(DPEphos) (10.00 g, 12.55 mmol) obtained above and 56.4% hydroiodic acid (3.13 g, 1.77 g as HI, 13.81 mmol) were added to acetone (650 g) and mixed at room temperature for 15 hours. After that, the obtained suspension was concentrated by evaporating the solvent under conditions of 30°C and 20 kPa, and the resulting concentrated suspension was separated into solid and liquid by vacuum filtration. The obtained solid was recrystallized at room temperature using dichloromethane and n-hexane to obtain a precipitate. The obtained precipitate was separated into solid and liquid by vacuum filtration, and the obtained solid was washed with n-hexane while filtering under vacuum. The solid after washing was dried under vacuum at 40°C for 15 hours to remove the solvent and obtain RhHI2(CO)(DPEphos).

[0085] Example 1 The carboxylic acid compounds were all prepared using a batch reaction method with a 30 ml Hastelloy pressure reactor. Cyclohexene (0.46 g, 5.57 mmol) and formic acid (0.92 g, 19.99 mmol) were added to acetic acid (6.08 g, 101.2 mmol) and pre-dissolved. The resulting mixed solution, along with the catalyst RhHI2(CO)(PPh3)2 (0.25 g, 0.28 mmol) obtained above, was added to a pressure reactor and sealed. The sealed pressure reactor was heated to 180°C in an aluminum block electric furnace and the reaction was carried out for 2.5 hours. After cooling, the contents of the pressure reactor were recovered, and qualitative and quantitative analysis of the reaction products contained in the recovered material was performed using a gas chromatography (GC) apparatus equipped with an FID detector. The internal standard method was used for quantitative analysis by GC. Qualitative analysis by GC revealed that the main product was cyclohexanecarboxylic acid (C6H 11 Along with COOH, cyclohexane (C6H 12 ), iodocyclohexane (C6H 11 I) Acetoxycyclohexane (C6H 11 By-products such as OAc were detected. Quantitative analysis revealed that the cyclohexene conversion rate (C6H) was high. 10 The conversion rate and the selectivity of each product were calculated. The results are shown in Table 2. The formulas used for these calculations are as follows: C6H 10 Conversion rate (mol%) = (1 - (number of moles of cyclohexene in the recovered material) / (number of moles of cyclohexene charged into the pressure reactor)) × 100 Selectivity of each product (mol%) = ((moles of product in the recovered material) / (moles of cyclohexene charged into the pressure reactor)) × 100 / (C6H 10 Conversion rate) × 100 In this example, cyclohexanecarboxylic acid could be produced with a high selectivity of 83.3 mol% without the use of a reaction accelerator.

[0086] Examples 2-14 The reaction was carried out in the same manner as in Example 1, except that the reaction conditions were changed as shown in Tables 1 and 2. The results are shown in Table 2.

[0087] [Table 1]

[0088] [Table 2]

[0089] The compounds in Tables 1 and 2 are as follows: TMAI: Tetramethylammonium iodide pTSA·H2O:p-toluenesulfonic acid monohydrate

[0090] Examples 15-25 The reaction was carried out in the same manner as in Example 1, except that the types and amounts of components used and the reaction conditions were changed as shown in Tables 3 to 6. For Examples 20-25, various alkenes listed in the table were used instead of cyclohexene, and their conversion rates and selectivity were calculated similarly by replacing cyclohexene with the respective alkenes in the above calculation formulas. The results are shown in Tables 4 and 6.

[0091] [Table 3]

[0092] [Table 4]

[0093] [Table 5]

[0094] [Table 6]

[0095] Example 26 The carboxylic acid compounds were all prepared using a batch reaction method with a 30 ml Hastelloy pressure reactor. Cyclohexene (0.42 g, 5.05 mmol) and pure water (0.27 g, 15.00 mmol) were added to acetic acid (6.29 g, 104.8 mmol) and pre-dissolved. The resulting mixed solution, along with RhHI2(CO)(PPh3)2 (0.23 g, 0.25 mmol) as a catalyst, was added to a pressure reactor and sealed. Next, CO gas (0.9 MPa) was filled into the container. The sealed pressure reactor was heated to 180°C in an aluminum block electric furnace and the reaction was carried out for 2.0 hours. The results are shown in Table 8. In this example, even when carbon monoxide and water were used as carboxylating agents, cyclohexanecarboxylic acid could be produced with a high selectivity of 73.8 mol% without the use of a reaction accelerator.

[0096] Examples 27-37 The reaction was carried out in the same manner as in Example 26, except that the reaction conditions were changed as shown in Tables 7 and 8. The results are shown in Table 8.

[0097] [Table 7]

[0098] [Table 8]

[0099] Example 38 The carboxylic acid compounds were all prepared using a batch reaction method with a 30 ml Hastelloy pressure reactor. Cyclohexene (0.41 g, 5.01 mmol) was added to acetic acid (6.27 g, 104.4 mmol), and the resulting mixed solution, along with RhHI2(CO)(PPh3)2 (0.23 g, 0.25 mmol) as a catalyst, was added to a pressure reactor and sealed. Next, CO gas (0.9 MPa) was filled into the container. Then, H2 gas (0.9 MPa) was filled into the container, and then liquefied CO2 (11.0 g, 250 mmol) was added using an HPLC pump with the pump head cooled to -15°C. The sealed pressure reactor was heated to 180°C in an aluminum block type electric furnace, and the reaction was carried out for 10.0 hours. The results are shown in Table 10. In this example, even when carbon dioxide and hydrogen were used as carboxylating agents, cyclohexanecarboxylic acid could be produced with a selectivity of 50.1 mol% without the use of a reaction accelerator.

[0100] Example 39 The reaction was carried out in the same manner as in Example 38, except that the reaction conditions were changed as shown in Tables 9 and 10. The results are shown in Table 10.

[0101] [Table 9]

[0102] [Table 10]

[0103] Comparative Example 1 Cyclohexene (0.47 g, 5.75 mmol), formic acid (1.00 g, 21.71 mmol), and p-toluenesulfonic acid monohydrate (0.19 g, 1.00 mmol) were added to acetic acid (6.01 g, 100.0 mmol) and pre-dissolved. The resulting mixed solution, along with [RhCl(CO)2]2 (0.056 g, 0.29 mmol as Rh atoms) as a catalyst, was added to a pressure reactor and sealed. The sealed pressure reactor was heated to 180°C in an aluminum block electric furnace and the reaction was carried out for 2.5 hours. The results are shown in Table 12.

[0104] Comparative Examples 2-8 The reaction was carried out in the same manner as in Comparative Example 1, except that the reaction conditions were changed as shown in Tables 11 and 12. The results are shown in Table 12.

[0105] [Table 11]

[0106] [Table 12]

Claims

1. Formula (1a): MH ｋ X ｌ L １ ｍ L ２ ｎ (1a) (In the formula, M represents at least one metal atom selected from the group consisting of Fe, Ru, Co, Rh, and Ir. X represents an iodine atom. L) １ L represents the ligand of carbon monoxide. ２ (where represents at least one ligand selected from the group consisting of amine compounds, imine compounds, and phosphine compounds. k represents a number of 1 or 2. l represents a number from 1 to 3. m represents a number from 0 to 5. n represents a number from 1 to 6.) A catalyst for the hydroxycarbonylation of alkenes, characterized by being represented as [the formula shown].

2. Formula (1b): MH ｋ X ｌ L １ ｍ L ２ ｎ (1b) (In the formula, M represents at least one metal atom selected from the group consisting of Fe, Ru, Co, Rh, and Ir. X represents an iodine atom. L) １ L represents the ligand of carbon monoxide. ２ L represents at least one ligand selected from the group consisting of amine compounds, imine compounds, and phosphine compounds. ２ If it contains a phosphorus atom, the phosphorus atom has a substituent with three or more carbon atoms. k represents a number of 1 or 2. l represents a number from 1 to 3. m represents a number from 0 to 5. n represents a number from 1 to 6. A metal complex characterized by being represented as such.

3. Formula (2): 【Chemistry 1】 (In the formula, R １ and R ２ R represents a hydrogen atom or an organic group having 1 to 24 carbon atoms, either identical or different. １ and R ２ The two may be linked together. From an alkene represented by (3), equation (3): 【Chemistry 2】 (In the formula, R １ and R ２ This is the same as in equation (2). R ３ A method for producing a carboxylic acid compound represented by (where represents a hydrogen atom or an organic group having 1 to 24 carbon atoms), The manufacturing method includes a step of reacting an alkene represented by formula (2) with formic acid and / or a formic acid ester, carbon dioxide and hydrogen, or carbon monoxide and water in the presence of the catalyst described in claim 1. A method for producing a carboxylic acid compound characterized by the above.

4. The method for producing a carboxylic acid compound according to claim 3, characterized in that the amount of catalyst used is 0.001 to 1 mole per mole of the alkene represented by formula (2).

5. The method for producing a carboxylic acid compound according to claim 3 or 4, characterized in that the reaction step is carried out in the presence of a solvent, the solvent comprising at least one selected from the group consisting of water, aromatic hydrocarbons, aliphatic hydrocarbons, and carboxylic acids.

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