KR20230015739A - Ag catalyst for carboxylation of aromatic compounds and method for producing aromatic carboxylic acid using same - Google Patents

Abstract

An Ag-based catalyst for carboxylation of a novel aromatic compound consisting of silver (Ag) and a base according to the present invention is used to produce aromatic carboxylic acid at a high yield through a reaction of an aromatic compound as a starting material with carbon dioxide (CO_2) at low temperature under conditions that supply pressure of CO_2 gas, compared to the conventional technology. In addition, the catalyst according to the present invention has high acceptability for a functional group of a starting material, so the catalyst can be used in producing high value-added aromatic carboxylic acid including polyethylene furanoate (PEF) that is used as a biodegradable building block from the aromatic compound.

Description

Ag-based catalyst for carboxylation of aromatic compounds and method for producing aromatic carboxylic acid using the same

The present invention is an Ag-based catalyst for carboxylation reaction that reacts a heteroaromatic compound and carbon dioxide among aromatic compounds to generate a carboxyl group at a carbon-hydrogen bonding site in a ring structure of the heteroaromatic compound, and manufacture of an aromatic carboxylic acid using the same It's about how.

Aromatic carboxylic acid compounds have high added value as structures included in organic materials for various uses.

A typical aromatic carboxylic acid compound can be obtained through an oxidation reaction of a tolyl functional group. However, in general, an excessive amount of an oxidizing agent is used in the oxidation reaction, and since the oxidizing agent may cause environmental problems, there is a problem that a lot of effort is required to remove by-products of the oxidizing agent after the reaction. In addition, in the case of an aromatic dicarboxylic acid compound, the carboxylic acid functional group generated in the first oxidation reaction reduces the electron density of the aromatic compound, thereby reducing the efficiency of the second oxidation reaction.

A method of reacting with carbon dioxide (CO ₂ ) after activating the carbon-halogen bond of an aromatic halogenated compound using a transition metal has also been reported. In this case, the Pd (Non-Patent Document 1) or Ni catalyst (Non-Patent Document 2) having a low oxidation state proceeds through an aryl metal intermediate produced through an oxidative addition reaction to a carbon-halogen bond. However, since this aryl metal intermediate has low reactivity with CO ₂ , there is a disadvantage in that the aryl metal intermediate must be reduced using an equivalent amount of a reducing agent.

Another method is a method of obtaining an aromatic carboxylic acid compound by reacting with CO ₂ after forming a carbon anion through the activation of a carbon-hydrogen bond of an aromatic compound. This method requires very strong base alkyl lithium, lithium amide, and alkyl magnesium reagents due to the high pKa of carbon-hydrogen bonds of aromatic compounds. In addition, most reactions using strong bases require a low reaction temperature (-78 ° C) to suppress side reactions, and there are limits to functional groups that can withstand the reaction conditions.

Direct carboxylation of carbon-hydrogen bonds of aromatic compounds using gold (Non-Patent Document 3) or copper catalyst (Non-Patent Document 4) can be performed instead of the condition using the strong base. In the case of the gold catalyst, the carboxylation reaction of a heterocyclic compound having a pKa of 35 or less proceeds depending on the type of N-heterocyclic carbene ligand used, and in the case of a copper catalyst, a heterocyclic compound having a pKa of less than 27 A carboxylation reaction of an aromatic compound proceeds. However, in both gold and copper catalysts, electron-rich heteroaromatics such as furan or thiophene do not undergo carboxylation.

In general, the carbon-hydrogen bond carboxylation reaction of electron-rich heteroaromatic compounds requires high thermal energy. When the reaction is performed at 160° C. for 15 hours using -6, the carboxylation reaction of furan and thiophene derivatives proceeds (Non-Patent Document 5). In addition, carboxylation of furan derivatives occurs efficiently under molten carbonate conditions (Non-Patent Document 6).

As an alternative, there is an example in which a carboxylation reaction is performed using an aluminum reagent, but in this case, a high CO ₂ pressure of 30 atm or more is required (Non-Patent Document 7). In addition, there is a case where a carboxylation reaction of a carbon-hydrogen bond of a heteroaromatic compound is carried out using a rhodium catalyst (Non-Patent Document 8), but in this case, a methylrodium intermediate must be necessarily generated, Reagents are required. Alternatively, after changing the photocatalyst to an excited state using light energy, carboxylic acid may be produced at room temperature through electron transfer to an electron-rich heteroaromatic compound (Non-Patent Document 9).

As such, currently known technologies have limitations in requiring high thermal energy, light energy, or high-energy compounds for the carboxylation reaction of electron-rich heteroaromatic compounds.

As described above, the method for preparing aromatic carboxylic acid from the carboxylation reaction of the carbon-hydrogen bond of an electron-rich heteroaromatic compound is an important technology for utilizing carbon dioxide, and various catalysts and reactions are being developed for this. However, the need for research on methods for producing heteroaromatic carboxylic acids using lower physical and chemical energy is continuously required.

The present inventors are searching for a catalyst system capable of producing aromatic carboxylic acid in high yield using a lower temperature or weak base than the reaction developed so far, and when using a silver catalyst system, it is possible to prepare carboxylic acid through activation of carbon-hydrogen bonds of aromatic compounds. discovered and completed the present invention.

J. Am. Chem. Soc., 131, 15974 (2009) J. Am. Chem. Soc., 134, 9106 (2012) J. Am. Chem. Soc., 132, 8858 (2010) Angew. Chem. Int. Ed. 49, 8674 (2010) Chemistry A European Journal 25, 3235 (2019) Nature 531, 215 (2016) J. Am. Chem. Soc., 124, 11379 (2002) Chem. Commun., 50, 14360 (2014) Chem., 6, 2658 (2020)

The present invention is to solve the above-mentioned problems, and proposes a highly reactive silver catalyst system in the reaction of generating an aromatic carboxylic acid through a carboxylation reaction of a carbon-hydrogen bond of an aromatic compound and a method for preparing an aromatic carboxylic acid using the same.

The present invention is a catalyst for producing an aromatic carboxylic acid from the reaction of an aromatic compound and carbon dioxide, wherein the catalyst contains silver as an active metal and contains a metal salt of at least one base selected from alkoxides, bistrimethylsilylamides, phosphates, and alkyl carbonates. characterized by

In one embodiment of the present invention, the silver is derived from a silver compound represented by the chemical formula Ag _n X, X means an anion having a negative charge in the range of -1 to -3, and n is an integer from 1 to 3 can

In another embodiment of the present invention, the silver (Ag) may be supported on a support.

The metal of the metal salt may be any one selected from Li, Na and K.

The catalyst may be a silver-alkoxide in which silver (Ag) and an alkoxide are combined.

The Ag-based catalyst is PR ¹ R ² R ³ A phosphine ligand represented by the formula may be further included. (In the above formula, R ¹ , R ² and R ³ are the same or different, respectively, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted halogenated alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted carbon number A cycloalkyl group having 3 to 30 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, a substituted or unsubstituted arylalkyl group having 7 to 50 carbon atoms, a substituted or unsubstituted heteroatom containing at least one O, N or S It may be any one selected from heteroaryl groups having 2 to 30 carbon atoms.)

The aromatic compound may be a substituted or unsubstituted pentagonal or hexagonal cyclic compound or bicyclic cyclic compound containing at least one heteroatom (oxygen, nitrogen, sulfur).

The aromatic compound may be at least one selected from the group consisting of <Compound 1> to <Compound 18>.

On the other hand, the present invention is a method for preparing an aromatic carboxylic acid from the reaction of an aromatic compound and carbon dioxide, comprising the steps of (a) introducing Ag, a base, an aromatic compound, and a solvent into a reactor; and (b) introducing carbon dioxide into the reactor and obtaining a carboxylation reaction product.

Ag added in the step (a) may be in the form of an Ag salt, and the mole number of the Ag may be 0.001 to 100 mol% of the aromatic compound.

As an embodiment of the present invention, the phosphine ligand mixed in step (a) is further added, and the amount of the ligand added may be 0.1 to 10 times the number of moles of Ag.

The solvent in step (a) is dimethylformamide (DMF), tetrahydrofuran (THF), 1,3-dimethyl-2-imidazolidinone, DMI), 1,4-dioxane (1,4-dioxane), and may be one or more selected from the group consisting of toluene.

The carbon dioxide pressure (P _CO2 ) in step (b) may be 0.1 to 20 bar, and the reaction temperature may be 40 to 150 °C.

The catalyst for preparing an aromatic carboxylic acid from the reaction of an aromatic compound and carbon dioxide according to the present invention can produce aromatic carboxylic acid in high yield through the reaction of an aromatic compound starting material with carbon dioxide (CO ₂ ) at a lower reaction temperature and lower carbon dioxide than in the prior art. can

In addition, the catalyst according to the present invention is composed of Ag as a catalytically active metal and a base material, has high tolerance for functional groups of an aromatic compound as a starting material, and produces aromatic compounds with high yield even under mild reaction conditions. can get angry

1 is a schematic diagram of a reaction in which an aromatic carboxylic acid is produced from an aromatic compound using the catalyst for carboxylation of the present invention.
2 is a view showing the mechanism of a reaction in which an aromatic carboxylic acid is produced from an aromatic compound using the carboxylation catalyst of the present invention.
3 is a diagram showing the Gibbs free energy profile of a reaction in which an aromatic carboxylic acid is produced from an aromatic compound using the catalyst for carboxylation reaction of the present invention.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In general, the nomenclature used herein is one well known and commonly used in the art.

Throughout the present specification, when a certain component is said to "include", it means that it may further include other components without excluding other components unless otherwise stated.

The present invention is a catalyst used for preparing an aromatic carboxylic acid from the reaction of a starting material containing an aromatic compound and carbon dioxide, and is characterized in that silver (Ag) is used alone as a catalytically active metal Ag-based catalyst for the reaction for preparing aromatic carboxylic acid provides

The Ag-based catalyst according to the present invention is composed of Ag as a catalytically active metal and a base material, has high tolerance for functional groups of an aromatic compound as a starting material, and produces aromatic compounds with high yield even under mild reaction conditions. can get angry

In the catalyst of the present invention, a silver compound represented by the chemical formula of Ag _n X may be provided as a precursor of Ag. In the above formula, X means an anion having a negative charge in the range of -1 to -3, and n is an integer from 1 to 3. As non-limiting examples of the Ag _n X, silver carboxylate (RCO ₂ Ag), silver acetate (CH ₃ CO ₂ Ag), silver pivalate (AgOPiv), silver carbonate (Ag ₂ CO ₃ ), silver oxide (Ag ₂ O), at least one selected from silver heptafluorobutyrate (C ₄ HAgF ₇ O ₂ ), silver pentafluoropropinate (C ₃ AgF ₅ O ₂ ), and silver trifluoroacetate (C ₂ AgF ₃ O ₂ ). can

In the present invention, Ag, the catalytically active metal, may be supported on a support. Here, the support includes all commonly used porous or non-porous materials, and as non-limiting examples, Al ₂ O ₃ , SiO ₂ , SiO ₂ -Al ₂ O ₃ , ZnO, MgO, CeO ₂ , ZrO ₂ , TiO ₂ , metal oxides such as; molecular sieves such as zeolite and MOF; carbonized materials such as activated carbon, graphite, carbon nanotubes, and fullerene; It may be one or more selected from the like, and a phosphine ligand may be bound to the support.

The content of Ag in the supported form may be supported within the range of 0.1 to 90 wt% with respect to the support.

In the Ag-based catalyst of the present invention, the base may be an alkoxide, bistrimethylsilylamide, phosphate, or alkyl carbonate, and preferably tert-butoxide or tert-butyl carbonate. The base may be introduced into the reaction system in a state bound to Ag, or may be introduced into the reaction system as a compound separate from Ag rather than in a state bound to Ag metal. At this time, the base may be used as a precursor of a metal-bound compound, and the metal may be selected from transition metals, alkali metals, and alkaline earth metals, preferably selected from Li, K, Na, Ca, Mg, and the like. It may be any one, and more preferably, it may be any one selected from Li, Na and K.

The Ag-based catalyst of the present invention may be a combination of Ag and a base. That is, for example, when the base is an alkoxide, it may be a silver-alkoxide in which Ag and the base are bonded.

In one embodiment of the present invention, the Ag catalyst system may further include a phosphine ligand. The phosphine ligand at this time is phosphine in which three alkyl or aryl groups are combined and substituted, and may be represented by Formula (1).

PR ¹ R ² R ³ Formula (1)

In Formula (1), R ¹ , R ² and R ³ are the same or different, respectively, and are a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted halogenated alkyl group having 1 to 30 carbon atoms, substituted or unsubstituted a cycloalkyl group having 3 to 30 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, a substituted or unsubstituted arylalkyl group having 7 to 50 carbon atoms, a substituted or unsubstituted cycloalkyl group having at least one O, N or S as a heteroatom It may be any one selected from heteroaryl groups having 2 to 30 carbon atoms. Preferably, the R ₁ to R ₃ may be any one of a methyl group, an n-butyl group, a cyclohexyl group, a phenyl group, a benzyl group and an adamantyl group, and as a non-limiting example, trimethylphosphine (P(CH ₃ ) ₃ ), triphenylphosphine (P(C ₆ H ₅ ) ₃ ), tricyclohexylphosphine (P(C ₆ H ₁₁ ) ₃ ), di(1-adamantyl)(n-butyl)phosphine (P(C ₁₀ H ₁₅ ) ₂ (C ₄ H ₉ )), tri(1-adamantyl)phosphine (P(C ₁₀ H ₁₅ ) ₃ ), diphenylcyclohexylphosphine (P(C ₆ H ₅ ) ₂ (C ₆ H ₁₁ )), dicyclohexylphenylphosphine (P(C ₆ H ₅ )(C ₆ H ₁₁ ) ₂ ), and the like, but as long as the ligand can coordinate with the metal, this Not limited.

In the reaction between a starting material containing an aromatic compound and carbon dioxide in which the Ag-based catalyst of the present invention is used, the aromatic compound has a substituted or unsubstituted pentagonal or hexagonal structure containing at least one heteroatom (oxygen, nitrogen, sulfur). It means a cyclic compound or a bicyclic cyclic compound. In this case, it may be a substituted or unsubstituted heteroaryl group having 2 to 30 carbon atoms including 1 to 3 O, N or S as heteroatoms in the ring structure.

At this time, 'substitution' in 'substituted or unsubstituted' is deuterium, a cyano group, a halogen group, a nitro group, an alkyl group having 1 to 24 carbon atoms, a cycloalkyl group having 3 to 24 carbon atoms, an alkenyl group having 2 to 24 carbon atoms, Alkynyl group having 2 to 24 carbon atoms, heteroalkyl group having 1 to 24 carbon atoms, aryl group having 6 to 24 carbon atoms, halogenated aryl group having 6 to 24 carbon atoms, arylalkyl group having 7 to 24 carbon atoms, alkylaryl group having 7 to 24 carbon atoms , Heteroaryl group having 2 to 24 carbon atoms, heteroarylalkyl group having 2 to 24 carbon atoms, alkoxy group having 1 to 24 carbon atoms, alkylamino group having 1 to 24 carbon atoms, diarylamino group having 12 to 24 carbon atoms, diaryl group having 2 to 24 carbon atoms Hetero arylamino group, C7-24 aryl (heteroaryl) amino group, C1-24 alkylsilyl group, C6-24 arylsilyl group, C6-24 aryloxy group, C6-24 aryl group It means that it is substituted with one or more substituents selected from the group consisting of oneyl group.

An aryl group, which is a substituent used in the compound of the present invention, is an organic radical derived from an aromatic hydrocarbon by removing one hydrogen. can

Specific examples of the aryl group include a phenyl group, o-biphenyl group, m-biphenyl group, p-biphenyl group, o-terphenyl group, m-terphenyl group, p-terphenyl group, naphthyl group, anthryl group, phenanthryl group, aromatic groups such as a pyrenyl group, an indenyl group, a fluorenyl group, a tetrahydronaphthyl group, a perylene group, a chrysenyl group, a naphthacenyl group, a fluoranthenyl group, and the like, wherein at least one hydrogen atom in the aryl group is deuterium atom, halogen atom, oxygen atom, hydroxyl group, nitro group, cyano group, silyl group, alkyl amino group (-N(R')(R″), R' and R" are independently of each other an alkyl group having 1 to 10 carbon atoms) , Amidino group, carboxyl group, sulfonic acid group, phosphoric acid group, C1-24 alkyl group, C1-24 alkenyl group, C1-24 alkynyl group, C1-24 heteroalkyl group, C6-24 aryl group , It may be substituted with an arylalkyl group having 6 to 24 carbon atoms, a heteroaryl group having 2 to 24 carbon atoms, or a heteroarylalkyl group having 2 to 24 carbon atoms.

An alkyl group, which is a substituent used in the present invention, is a substituent in which one hydrogen is removed from an alkane, and has a structure including a straight chain type and a branched type, and specific examples thereof include methyl, ethyl, propyl, isopropyl, isobutyl, sec -butyl, tert-butyl, pentyl, iso-amyl, hexyl and the like, and one or more hydrogen atoms in the alkyl group may be substituted with the same substituents as in the case of the aryl group.

'Cyclo' in the cycloalkyl group, which is a substituent used in the compound of the present invention, means a substituent having a structure capable of forming a single ring or multiple rings of saturated hydrocarbons in the alkyl group, and specific examples of the cycloalkyl group include cyclopropyl, cyclo butyl, cyclopentyl, cyclohexyl, methylcyclopentyl, methylcyclohexyl, ethylcyclopentyl, ethylcyclohexyl, adamantyl, dicyclopentadienyl, decahydronaphthyl, norbornyl, bornyl, isobornyl and the like. One or more hydrogen atoms in the cycloalkyl group may be substituted with the same substituents as in the case of the aryl group.

The alkoxy group, which is a substituent used in the compound of the present invention, is a substituent in which an oxygen atom is bonded to the terminal of an alkyl group or cycloalkyl group, and specific examples thereof include methoxy, ethoxy, propoxy, isobutyloxy, sec-butyloxy, pentyloxy, iso -amyloxy, hexyloxy, cyclobutyloxy, cyclopentyloxy, adamantaneoxy, dicyclopentanoxy, bornyloxy, isobornyloxy, etc., wherein at least one hydrogen atom in the alkoxy group is the aryl group It can be substituted with the same substituent as in the case of

Specific examples of the arylalkyl group, which is a substituent used in the compound of the present invention, include phenylmethyl (benzyl), phenylethyl, phenylpropyl, naphthylmethyl and naphthylethyl, and the like, and at least one hydrogen atom in the arylalkyl group is the aryl Substitution with the same substituent as in the case of a group is possible.

Preferably, the aromatic compound may be at least one selected from the group consisting of Compounds 1 to 18.

In addition, the present invention provides a method for producing an aromatic carboxylic acid from an aromatic compound in the presence of a catalyst for carboxylation of the aromatic compound, comprising: (a) introducing Ag, a base, an aromatic compound, and a solvent into a reactor; (b) introducing carbon dioxide into the reactor and obtaining a carboxylation reaction product; it is possible to provide an aromatic carboxylic acid production method comprising the.

Ag added in the step (a) may be 0.001 to 100 mol%, preferably 10 to 100 mol%, relative to the aromatic compound. When the Ag input amount is less than 0.001 mol %, the reaction yield may be insignificant.

At this time, Ag may be in the form of metal particles, but is preferably added in the form of silver salt. The form of the silver salt is as described above.

In addition, the base may be added and mixed in an amount of 0.1 to 3 equivalents, preferably 0.5 to 2 equivalents, compared to the aromatic compound. When the amount of the base added is less than 0.1 equivalent, the intermediate in which the catalyst of the present invention is bonded to the aromatic compound is protonated, thereby reducing the carboxylation reaction, and when adding more than 3 equivalents of the base, the reaction Doesn't have much of an impact.

In step (a), a phosphine ligand may be further added. At this time, the input amount of the ligand may be 0.1 to 10 times the number of moles of Ag, preferably 0.2 to 5 times the number of moles, or 0.5 to 2 times the number of moles of Ag. When the number of moles of the ligand is less than 0.1 of the number of moles of the silver salt, the stabilizing effect of silver particles by the ligand is insignificant, and when the number of moles of the ligand is greater than 10 times, the yield decreases.

The solvent in step (a) is dimethylformamide (DMF), tetrahydrofuran (THF), 1,3-dimethyl-2-imidazolidinone, DMI), 1,4-dioxane (1,4-dioxane), and at least one selected from the group consisting of toluene (toluene), preferably at least one of DMF and DMI. At this time, the amount of the solvent may be 1 to 5 mL based on 1 mmol of the aromatic compound as a reactant, and preferably 2 to 4 mL based on 1 mmol of the aromatic compound.

In the step (a), the order of adding the aromatic compound, solvent, base, Ag or phosphine ligand is not affected, and the solvent may be added first, the base or Ag may be added first, or both may be added simultaneously. In addition, after preparing the Ag-based catalyst of the present invention in advance, it may be introduced into the reactor together with an aromatic compound and a solvent. In this case, the Ag-based catalyst may be a combination of Ag and a phosphine ligand, a combination of Ag and a base, or a combination of Ag, a base, and a phosphine ligand.

The carbon dioxide pressure (P _CO2 ) in step (b) may be 0.1 to 20 bar, preferably 1 to 5 bar. When the pressure of carbon dioxide is less than 0.1 bar, carboxylic acid may not be produced.

In addition, the carboxylation reaction temperature in step (b) may be 40 to 150 °C, preferably 60 to 115 °C, and more preferably 70 to 100 °C. When the temperature is less than 40 ° C., the carboxylation reaction may not proceed, and when the temperature exceeds 150 ° C., side reactions or decomposition reactions of reactants occur, resulting in a decrease in yield.

In step (b), the carbon dioxide may replace all of the internal gas with carbon dioxide, or may be in a form in which some carbon dioxide is present in the mixed gas.

The reaction time of step (b) may be 0.5 to 24 hours. Since productivity may be lowered when the reaction time is long, it is necessary to select an appropriate range in the relationship between reaction time and yield.

In order to help the understanding of the present invention, as an example, a reaction and mechanism of generating aromatic carboxylic acid using a catalyst for carboxylation of a thiophene compound as a reactant are shown in FIGS. 1 and 2 .

Referring to FIG. 1, which is an example of a carboxylation reaction of an aromatic compound, a catalyst prepared from a thiophene compound as a starting material and a reactant, silver salt Ag ₂ CO ₃ , ligand PAd ₂ n-Bu, and base LiOt-Bu is used as a solvent. After being added to DMF, a reaction was performed at 90° C. for 15 hours to obtain a carboxylic acid aromatic compound, and methyl iodide (MeI) was additionally added and reacted to finally obtain an esterified carboxylic acid aromatic compound.

Referring to FIG. 2 for the carboxylation reaction mechanism of an aromatic compound, the catalyst (A) prepared from the silver salt Ag ₂ CO ₃ , the ligand PAd ₂ n-Bu, and the base LiOt-Bu reacts with the reactants to form an aromatic compound. After forming an intermediate (B) combined with, an intermediate (C) in which carbon dioxide (CO ₂ ) is bonded between silver (Ag) and a reactant in the intermediate (C) is finally protonated through reaction with a base A carboxylic acid aromatic compound is produced.

Hereinafter, the present invention will be described in more detail through Examples, Comparative Examples and Experimental Examples. This is a representative example related to the present invention, and it is revealed that the scope of application of the present invention cannot be limited only by this.

<Preparation Example> Preparation of catalyst for carboxylation of aromatic compounds containing AgOPiv coordinated with phosphine in advance

Di(adamantan-1-yl)(butyl)phosphine, a phosphine ligand equivalent to 1 mmol of silver pivalate (AgOPiv), a silver salt, in a 20 ml scintillation vial in a glove box purged with argon gas. ⁿ BuAd ₂ P) and add 15 mL of diethyl ether. After stirring at room temperature for 24 to 72 hours, vacuum filtration using a glass frit funnel while flowing diethyl ether as a solvent to obtain a reaction product containing catalysts for carboxylation of aromatic compounds No. 21 to 23 in Table 1 below.

<Experimental Example 1> Preparation of aromatic carboxylic acids according to types of catalysts for aromatic carboxylic acid production reactions

1 mmol of tert-butyl thiophene-2-carboxylate as a tert-butyl aromatic compound in a 20 ml scintillation vial in a stainless steel autoclave reactor, based on 1 mmol of the thiophene carboxylate Table 1 After adding a silver salt and a ligand in an amount described in mmol%, a base equivalent to the thiophene carboxylate and 3 ml of the solvent described in Table 1, the air inside the reactor was replaced with carbon dioxide gas (CO ₂ ), and the CO ₂ pressure was adjusted to 2 to 10 bar. After stirring the reactor at 25 to 120 °C for 1 to 15 hours, the temperature was cooled to room temperature. After taking out the vial from the reactor, 3 equivalents of methyl iodide was added, followed by stirring at 90 °C for 2 hours. For the reaction product in the vial, diethylether and distilled water were added and mixed to obtain a layer-separated organic solution, and after removing moisture using magnesium sulfate (MgSO ₄ ), the organic solution from which the moisture was removed A reaction product containing an aromatic carboxylic acid is obtained through concentration and column chromatography. After 1H NMR measurement of the reaction product containing the aromatic carboxylic acid, the yield was calculated through [Equation 1] below and shown in [Table 1].

[Equation 1] Calculation of product yield (isolation yield, %) through 1H NMR measurement

Aromatic carboxylic acid product yield (%) = product 1H NMR peak integration / internal standard 1H NMR peak integration (1.0) X 100

According to Table 1, it can be seen that no carboxylation reaction occurred when AgOPiv was reacted at 90 °C for 1 hour without using a base. It was found that the reaction proceeded when phosphine ligand and t-butoxide or phosphine ligand and lithium tert-butyl carbonate were used, and it was effective when other bases were used. It wasn't. It can be seen that it has reactive activity for various phosphine ligands, and in particular, PAd ₂ ⁿ Bu showed the best performance. When the reaction was performed using the phosphine-coordinated AgOPiv obtained in the above Preparation Example, the yield was improved with increasing time. When Ag ₂ CO ₃ was used as a catalyst precursor, 79% yield was obtained when 20 mol% of PAd ₂ ⁿ Bu was used and the reaction time was increased to 15 hours.

<Experimental Example 2> Preparation of aromatic carboxylic acids according to types of aromatic compounds

As shown in [Table 2] below, the above experiment except that an aromatic compound derivative was added instead of tert-butyl thiophene-2-carboxylate of Experimental Example 1 as a reactant. A reaction product containing an aromatic carboxylic acid was prepared by the same method as in No. 27 in Table 1 of Example 1, but in the case where the aromatic compound derivatives were 2h and 2i, the same method as in No. 29 in Table 1 of Experimental Example 1 was prepared. The same method as was performed, except that when the aromatic compound derivative was 2u, 50 mol% of silver salt Ag ₂ CO ₃ and 100 mol% of phosphine ligand PAd ₂ Bu were added, 27 in Table 1 of Experimental Example 1. A reaction product containing an aromatic carboxylic acid was prepared by the same method as in Burn. An esterification product was obtained by using methyl iodide (MeI) for the reaction product. The yield of the obtained esterification product was calculated by dividing the methyl carboxylated compound, which is a reaction product with methyl iodide (MeI), by column chromatography and then dividing by the molecular weight. The yield was determined by comparing the number of moles with the number of moles of the starting material.

Referring to Table 2, it was generally observed that the yield of a thiophene derivative containing an electron withdrawing group at the position of carbon atom 2 was excellent.

The thiophene derivatives containing an aryl, cyano, or carbonyl group at the position of the carbon atom #2 showed yields of carboxylated products exceeding 60%. In particular, the thiophene derivatives containing cyano and carbonyl groups of the examples may cause side reactions under conditions of lithium tert-butoxide. Therefore, a yield of more than 60% was recorded using lithium tert-butyl carbonate instead of lithium tert-butoxide.

The yield of the carboxylation product of 2,3-chlorothiophene was 73%, which was superior to that of 2-halothiophene substituted with a single halogen atom.

3-Bromothiophene obtained carboxylation reaction products (2ja, 2jb, 2jc) in which CO ₂ was inserted at the position of carbon atom 2, carbon atom 5, or carbon atom 2 and 5. The ratio of the carboxylation reaction product is 1 : 6.3 : 1.4, and it is estimated that the regioselectivity of the carboxylation reaction is related to the pKa of the CH bond in the reaction product. The position's pKa of 27.9 supports this.

In the case of 3-phenylthiophene, a carboxylation reaction product (2ka, 2kb) in which CO ₂ was inserted at the position of the 2nd or 5th carbon atom was obtained. The ratio of the carboxylation reaction product is 1.7: 1, and the calculated pKa at position 5 is 33.2 and the pKa at position 2 is similar to 33.1, so that the regioselectivity of the carboxylation reaction is 3-phenyl substituent together with the pKa value. is assumed to be determined by the combined volume effect.

The present invention has been described above with reference to the accompanying drawings and embodiments, but these are merely exemplary, and those skilled in the art can make various modifications and equivalent other embodiments therefrom. will understand Therefore, the technical protection scope of the present invention should be determined by the claims below.

Claims (12)

As a catalyst for the reaction of producing an aromatic carboxylic acid from the reaction of an aromatic compound and carbon dioxide,
The catalyst includes silver as an active metal and a metal salt of one or more bases selected from alkoxide, bistrimethylsilylamide, phosphate, and alkyl carbonate Ag-based catalyst for carboxylation of aromatic compounds. According to claim 1,
The silver is derived from a silver compound represented by the chemical formula Ag _n X, X means an anion having a negative charge in the range of -1 to -3, and n is an integer of 1 to 3 Carboxylation of an aromatic compound, characterized in that Ag-based catalyst for reaction. According to claim 1,
Ag-based catalyst for carboxylation of aromatic compounds, characterized in that the silver (Ag) is supported on a support. According to claim 1,
Ag-based catalyst for carboxylation of aromatic compounds, characterized in that the metal of the metal salt is any one selected from Li, Na and K. According to claim 1,
The catalyst is an Ag-based catalyst for the carboxylation reaction of an aromatic compound, characterized in that the silver-alkoxide in the form of a combination of silver (Ag) and alkoxide. According to claim 1,
The Ag-based catalyst is PR ¹ R ² R ³ An Ag-based catalyst for carboxylation of an aromatic compound, further comprising a phosphine ligand represented by the formula.
(In the above formula, R ¹ , R ² and R ³ are the same or different, respectively, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted halogenated alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted carbon number A cycloalkyl group having 3 to 30 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, a substituted or unsubstituted arylalkyl group having 7 to 50 carbon atoms, a substituted or unsubstituted heteroatom containing at least one O, N or S It may be any one selected from heteroaryl groups having 2 to 30 carbon atoms.) According to claim 1,
The aromatic compound is an Ag-based catalyst for carboxylation of an aromatic compound, characterized in that at least one selected from the group consisting of <Compound 1> to <Compound 18>.

As a method for producing an aromatic carboxylic acid from the reaction of an aromatic compound and carbon dioxide,
(a) introducing Ag, a base, an aromatic compound, and a solvent into a reactor; and
(b) injecting carbon dioxide into the reactor and obtaining a carboxylation reaction product; A method for producing an aromatic carboxylic acid comprising the. According to claim 8,
Ag added in step (a) is in the form of an Ag salt, and the number of moles of Ag is 0.001 to 100 mol% of the aromatic compound. According to claim 8,
A method for producing an aromatic carboxylic acid, characterized in that the phosphine ligand mixed in step (a) is further added, and the amount of the ligand added is 0.1 to 10 times the number of moles of Ag. According to claim 8,
The solvent in step (a) is dimethylformamide (DMF), tetrahydrofuran (THF), 1,3-dimethyl-2-imidazolidinone, A method for producing an aromatic carboxylic acid, characterized in that at least one selected from the group consisting of DMI), 1,4-dioxane and toluene. According to claim 8,
The carbon dioxide pressure (P _CO2 ) in the step (b) is 0.1 to 20 bar, and the reaction temperature is 40 to 150 ℃ Aromatic carboxylic acid production method, characterized in that.

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