JPS61212523A - Production of aromatic carboxylic acid - Google Patents

Abstract

PURPOSE:To obtain the titled substance in one step, in high yield, by reacting an aromatic compound having substitutible H atom on the nucleus with CO2 in the presence of a Pd catalyst and an organic P compound, and preferably in the copresence of molecular oxygen or a peroxide compound. CONSTITUTION:An aromatic carboxylic acid can be produced by reacting an aromatic compound having substitutible H atom on the nucleus (e.g. benzene, biphenyl, naphthalene, furan, etc.) with CO2 and molecular oxygen or a peroxide compound (e.g. t-butyl hydroperoxide) in the presence of a Pd catalyst and an organic P compound at 50-200 deg.C and 5-100atm. The Pd catalyst is an organic salt (e.g. Pd carboxylate, beta-diketone complex, ketoester complex, etc.) or an inorganic salt (e.g. nitrate, chloride, etc.), and its amount is >=1X10<-5> Pd metal per 1g-mol of the starting substance. The organic P compound is e.g. monophosphine and its amount is 0.5-5mol per 1mol of the Pd catalyst.

Description

[Detailed description of the invention] a. industrial The present invention relates to a method for producing aromatic carboxylic acids.

More specifically, the present invention relates to a method for producing an aromatic carboxylic acid by reacting an aromatic compound having at least one substitutable hydrogen atom on a carbon nucleus with carbon dioxide gas to carboxylate the carbon nucleus.

According to the present invention, it is possible to obtain the desired aromatic carboxylic acid from carbon dioxide gas and an aromatic compound in one step without using auxiliary means such as light.

b. Prior Art Various methods are known for carboxylating aromatic compounds to obtain aromatic carboxylic acids. For example, Jou
RNA of Chemical Science
ety.

Chemical Communication 2
20 (1980) describes a method for obtaining aromatic carboxylic acids by reacting aromatic compounds with -carbon oxide in the presence of palladium acetate, and the Journal of Ch.
chemical society.

Chemical Con+unication 1
32 (1982), in the same manner as the previous example,
A method for obtaining carboxylic acid anhydride by adding 1,2-dibromoethane is described.

Furthermore, a method using carbon dioxide gas as a carboxylating agent is
Various studies have been conducted using light in research as a model for the photosynthetic system of plants.

Such a method is described, for example, in Nature, Vol. 275, p. 301, in which an electron transport substance such as pyrene or perylene and an electron acceptor substance such as 1,4-dicyanobenzene or 9,10-dicyanoanthracene are mixed together with water in a polar solvent, For example, it has been confirmed that formic acid is produced by irradiating a mercury arc in acetonitrile and blowing carbon dioxide gas for 8 hours.

Also Journal Chelcal 5ociet
y, Chea+1-cal Comff1unica
tion, page 237 (1975), an aromatic compound such as phenanthrene was treated in the presence of an amine such as dimethylaniline in a polar solvent such as dimethyl sulfoxide at a CO2 pressure of 4 KW ts-2 and a mercury lamp at 7 kW.
Irradiate a Pyrex container at a distance of cIR and 1 at room temperature.
It is disclosed that when the reaction was carried out for 4 hours, carboxylic acid was obtained in a yield of 33 to 55% based on the reacted phenanthrene. This reaction is the first known example of carbon dioxide fixation in an abiotic system.

However, since these methods using carbon oxide use carbon monoxide as a raw material, they have disadvantages in terms of cost and handling from an industrial perspective. - The method using carbon dioxide using a force tip has the disadvantage of increasing production and operating costs for light irradiation.

Therefore, some of the present inventors conducted intensive research on a method of carboxylating aromatic compounds and CO2 in the presence of a catalyst without using light. The authors proposed that the process proceeds advantageously (see Japanese Patent Laid-Open No. 163338/1983).

Structure of the C0 Invention Therefore, the present inventors further improved the above-mentioned proposed method and conducted research on a method in which the palladium catalyst acts more catalytically to obtain a large amount of the target product, and as a result, the present invention was achieved. did.

That is, the present invention provides a process for producing a reactive aromatic carboxylic acid, which is characterized by reacting an aromatic compound having at least one substitutable hydrogen atom on a nuclear carbon with carbon dioxide gas in the presence of a palladium catalyst and an organic phosphorous compound. It is the law.

According to the method of the present invention, without using light or the like,
By catalytically acting with a palladium catalyst and introducing carbon dioxide gas into the aromatic nucleus to carboxylate it, the corresponding aromatic benzenecarboxylic acid can be advantageously obtained, and its industrial significance is very great.

The starting material used in the present invention may be an aromatic compound having at least one hydrogen atom directly bonded to a carbon atom constituting an aromatic nucleus, and may be monocyclic, polycyclic, or fused ring.

It may also be a heterocyclic aromatic compound having oxygen, nitrogen, or sulfur atoms in the ring. Examples of these include the following.

(A) Monocyclic aromatic compound For example, benzene and its substituted derivatives, etc. (B) Polycyclic aromatic compound For example, biphenyl, biphenyl ether.

Terphenyl, quaterphenyl and substituted derivatives thereof, etc. (C) Fused ring aromatic compounds such as naphthalene, anthracene, phenanthrene and substituted derivatives thereof (D) Heterocyclic aromatic compounds such as furan, thiophene, virol and substituted thereof These aromatic compounds such as derivatives need only have at least one, preferably at least two, hydrogen atoms directly bonded to the carbon atoms constituting the aromatic nucleus, and the aromatic nucleus may have no adverse effect on the reaction. Unless otherwise specified, substituents may be present. Such substituents include, for example, alkyl groups or cycloalkyl groups such as methyl, ethyl, propyl, butyl, and cyclohexyl groups; hydroxyalkyl groups such as hydroxymethyl and hydroxyethyl groups; methoxy groups.

Alkoxy groups such as ethoxy groups; carboxyl groups or alkyl ester groups thereof such as hydroxycarbonyl groups and alkoxycarbonyl groups; fluorine.

Examples include halogen such as chlorine; cyano group; nitro group; formyl group; acyl group such as acetyl group, propionyl group, and benzoyl group.

Specific examples of aromatic compounds used in the present invention are as follows.

(1) Aromatic compounds For example, benzene, toluene, xylene (o, m.

p), ethylbenzene, cumene, trimethylbenzenes, tetramethylbenzene, naphthalene.

α- or β-methylnaphthalene, dimethylnaphthalenes, ethylnaphthalene, anthracene.

phenanthrene, biphenyl, 4-methylbiphenyl,
3-methylbiphenyl, 3.3'-dimethylbiphenyl, etc. ('2J Aromatic carboxylic acid or its ester, such as benzoic acid, methyl benzoate, ethyl benzoate, toluic acid (0, ■, p), methyl toluate (o , m, p)
, α-naphthoic acid, β-naphthoic acid, methyl-α-naphthoic acids, methyl-β-naphthoic acids, methyl α-naphthoate, methyl β-naphthoate, ethyl α-naphthoate, ethyl β-naphthoate, diphenyl Monocarboxylic acid (2-, 3- or 4-) or its methyl.

Ethyl, propyl, butyl esters, etc. (3) Aromatic ethers, such as anisole, diphenyl ether, diphenyl ether carboxylic acid, diphenyl ether, or their esters, etc. (4) Other aromatic compounds, such as monochlorobenzene, dichlorobenzene, chlornaphthalene, benzonitrile , tolnitrile, cyanonaphthalene, nitrobenzene.

As the palladium catalyst used in the present invention, organic and inorganic acid salts of palladium are used, such as acetophenone, furan, thiophene, and virol. The palladium salt used is generally a divalent salt. However, 0@j palladium complexes or tetravalent salts can be used as well.

Such palladium organic salts include, for example, palladium carboxylate, β-diketone complex salts. This includes ketoester complex salts.

The palladium carboxylate may be one in which at least one carboxyl residue and palladium are bonded. The A group constituting the carboxyl residue A-Coo- bonded to palladium is an alkyl group or a cycloalkyl group.

Examples include aryl groups and those substituted with substituents that do not inhibit the reaction (for example, the groups <a) to (i) shown above as substituted derivative groups of the aromatic compound that is the starting material). can.

Among these, preferred are aliphatic monocarboxylic acids having 2 to 20 carbon atoms, aliphatic di- or tricarboxylic acids having 3 to 20 carbon atoms, alicyclic carboxylic acids having 6 to 20 carbon atoms, and benzene mono- or dicarboxylic acids. -Carboxylic acid.

Naphthalene dicarboxylic acid, dicarboxylic acid, etc. Specific examples include acetic acid, propionic acid, iso- or n-butyric acid, caproic acid, malonic acid, succinic acid, adipic acid, cyclohexanecarboxylic acid, naphthenic acid, and benzoic acid. acid, toluic acid, α-naphthoic acid, β-naphthoic acid, etc., and particularly preferred are aliphatic monocarboxylic acids having 2 to 4 carbon atoms.

In the present invention, β-diketone complex salts of palladium are likewise advantageously used as catalysts. Therefore, in the method of the present invention, the β-diketone complex salt of palladium may be added to the reaction system, and the other palladium compounds and the β-diketone are separated so that the β-diketone complex salt of palladium is formed in the reaction system. It may be added to the reaction system. β in the reaction system
- Compounds that give diketones include, for example, acetylacetone, propionylacetone, and butylacetone.

Isobutyrylacetone, caproylacetone, C-methylacetylacetone, tetraacetylacetone, benzoylacetone, dibenzoylmethane.

Examples include trifluoroacetylacetone, hexafluoroacetylacetone, benzoyltrifluoroacetone, β-naphthoyltrifluoroacetone, acetoacetic acid, acetoacetic ester, trifluoroacetoacetic acid, trifluoroacetoacetic ester, and the like.

Examples of palladium compounds that form complex salts of β-diketones in the reaction system include palladium nitrates, perchlorates, chlorides, acetates, oxides, and hydroxides.

Examples of palladium inorganic salts include nitrates, perchlorates, chlorides, oxides, and hydroxides.

The palladium catalyst used in the method of the present invention may be used in a very small amount, and the amount used is not particularly limited. Generally 1 as palladium metal per gram mole of starting material
It is at least 10'4 gram atoms, preferably at least 10'5 gram atoms, and the upper limit thereof is not particularly limited, but is determined by itself from an economical or industrial standpoint. After the palladium catalyst used in the method of the present invention is separated from the reaction product, it can be reused as it is or after being purified or activated.

In the method of the present invention, the use of an organic phosphorus compound allows the palladium catalyst to act catalytically. Such organic phosphorus compounds include phosphines such as mono-, di- or tri-phosphines.

Examples include bosphites such as mono-, di-, or tri-phosphites, and phosphine oxytos such as mono-, di-, or tri-bosphine oxides, and among these, monophosphines, monophosphites, and monophosphine oxides are preferred. .

Examples of this include phosphines such as triphenylphosphine, tri(methylphenyl)phosphine, tri(methoxyphenyl)phosphine; trimethylphosphite;
Triethyl phosphite, tripropyl phosphite,
Examples include phosphites such as tributyl phosphite and triphenyl phosphite; and phosphine oxides such as triethylphosphine oxyto and triphenylphosphine oxyto.

These organic phosphorus compounds are advantageously present in the reaction system in an amount of 0.1 to 20 moles, preferably 0.5 to 5 moles, relative to the palladium catalyst used.

The carbon dioxide used in the present invention may consist essentially of carbon dioxide, but may contain other gases that do not inhibit the reaction.

Examples of such gases include nitrogen, lower hydrocarbons such as methane and ethane, hydrogen, helium, and argon.

In carrying out the present invention, the reaction pressure is usually in the range of normal pressure to 300 atm, preferably 2 to 200 atm, particularly preferably 5 to 100 atm.

Further, the partial pressure of carbon dioxide in the reaction system is not particularly limited, but it is usually 1 atm or more, particularly preferably 2 atm or more.

The reaction temperature of the present invention is generally 30 to 300°C, preferably 50 to 200°C, and the reaction time varies depending on the reaction conditions, but is preferably 10 minutes to 500 hours, preferably 30 minutes to 300 hours. .

The present invention can be carried out either in the presence or absence of a solvent, but when carried out in the absence of a solvent, it is important to maintain the reaction system in a liquid phase using the starting material. This is one of the most preferred embodiments. When a solvent is used, any solvent may be used as long as it is stable under the reaction conditions and does not adversely affect the reaction.

When using a solvent, the following are preferred.

(1) Carboxylic acids such as acetic acid, pro-pionic acid, butyric acid, benzoic acid, etc. Carboxylic acid anhydrides such as acetic anhydride, propionic anhydride, butyric anhydride, phthalic anhydride, succinic anhydride, etc. Carboxylic acid esters such as acetic acid Methyl, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate.

Methyl butyrate, ethyl butyrate, methyl benzoate, ethyl benzoate, etc. Ethers such as ethyl ether, tetrahydrofuran.

Dioxane, glyme, diglyme, etc. (V) Ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, etc. Alcohols such as methanol, ethanol, butanol.

Nitriles (e.g. acetonitrile, propionitrile, etc.) Organic halides (e.g. chloroform, carbon tetrachloride, ethylene dichloride, perchlorethylene, etc.) The above-mentioned media are merely examples, and are not limited to these in any way. isn't it. Moreover, the above-mentioned medium can be used alone or in a mixture of two or more.

When such a medium is used, the amount used may be any amount that is at least the amount that allows the reaction system to flow (including slurry).

In the process of the invention, the presence of molecular oxygen allows the palladium catalyst to act catalytically.

Molecular oxygen has a partial pressure of 1 atmosphere or more in the reaction system,
It is preferable to use it so that the pressure is preferably 2 atmospheres or more.

Furthermore, in the method of the present invention, the palladium catalyst can be made more catalytic by using a peroxide compound. Examples of such peroxide compounds include hydrogen peroxide, t-butyl hydroperoxide, di-t-butyl peroxide, and benzoyl peroxide.

By carrying out the method of the present invention described above, a carboxyl group can be introduced into an aromatic compound, and an aromatic carboxylic acid can be obtained in one step and in a high yield per palladium catalyst.

The present invention can be carried out either batchwise or continuously.

The present invention will be described below with reference to Examples, but the present invention is not limited thereto.

Example 1 30 g of benzene and 0 of palladium acetylacetonate were placed in a stainless steel autoclave with a capacity of 100 cc.
．． 0612 or (0,2mi+ol) and triphenylphosphine oxyto 0,111gr (0,4ss
ol), charged with 35 kg/dG of carbon dioxide and 15 kg/dG of oxygen at room temperature, and heated to 130°C.
The reaction was allowed to proceed for 20 hours.

As a result, benzoic acid per palladium catalyst used was 15
A yield of 0 mol% was obtained, and biphenyl was produced in a yield of 1020% based on the palladium catalyst used.

Example 2 In a stainless steel autoclave with a capacity of 10000, 20 gr of benzene, 5 g of acetic acid, 0.061212 r (0,2 swol) of palladium acetylacetonate and 0.111 gr (0,2 swol) of triphenylphosphine oxide were added.
4siol), carbon dioxide 35Ny/aJG and oxygen 15Nf/aIG at room temperature, and heated to 100℃ for 2 hours.
The reaction was carried out for 00 hours. As a result, 111 mol% of benzoic acid and 400% of biphenyl were produced based on the palladium catalyst.

Examples 3 to 5 15 cc of a mixture of benzene and acetic acid (4:1 by weight) was placed in a glass reaction vessel with a capacity of 5 oc, and palladium acetate [Pd (OAc > 2)] was added thereto.
0.1110+, t-butyl pen oxide 40
imo I and the phosphorus compounds shown in Table 1 below were added, the tube was sealed, and the mixture was stirred and reacted at 80° C. for 72 hours in a carbon dioxide atmosphere.

The reaction results are shown in Table 1 below. The yield is expressed in mol % based on the palladium used.

(Leaving space below) Table 1 Examples 6 to 8 Into the same container as Examples 3 to 5, put 15CQ of benzene and acetic acid mixture (4:1 by weight), fill it with CO2, and add palladium acetyl into the container. acetonate 0
．． 1ml t-butyl peroxide 40110
1 and the phosphorus compounds shown in Table 2 below were added, the tube was sealed, and the mixture was stirred at 80° C. for 72 hours to react. The reaction results are shown in Table 2 below.

(Margin below) Table 2 In the case of Example 8, t-butyl peroxide 10a
Add nol first, then 5■0 6 times every 2 hours.
1 was added.

Examples 9-11 In the same container as Examples 3-5, the following aromatic compound and a mixture of Ooform and acetic acid (4=1 by weight) 15
After putting in cc and filling with CO2, add acetic acid halachim [Pd” (OAc) 2 ] 0.211
mol.

(10 mmol of -butyl peroxide and Table 3 below
The phosphorus compound shown in Table 3 was added, the tube was sealed, and the reaction was allowed to proceed at 80° C. with stirring for the time shown in Table 3. The results are shown in Table 3 below.
It was shown to.

Table-3

Claims (1)

[Claims] 1. A corresponding aromatic compound characterized by reacting an aromatic compound having at least one substitutable hydrogen atom in the nuclear carbon with carbon dioxide gas in the presence of a palladium catalyst and an organic phosphorus compound. Method for producing carboxylic acid. 2. Corresponding aromatic carboxylic acid characterized by reacting an aromatic compound having at least one substitutable hydrogen atom in the nuclear carbon with carbon dioxide gas and molecular oxygen in the presence of a palladium catalyst and an organic phosphorus compound manufacturing method. 3. The preparation of a corresponding aromatic carboxylic acid, which is characterized by reacting an aromatic compound having at least one substitutable hydrogen atom in the nuclear carbon with carbon dioxide gas and a peroxide compound in the presence of a palladium catalyst and an organic phosphorus compound. Manufacturing method.