JPS59163338A - Production of aromatic carboxylic acid - Google Patents

Abstract

PURPOSE:To produce an aromatic carboxylic acid in one step, by reacting an aromatic compound having at least one substitutable H at the nucleus with CO2 in the presence of a palladium catalyst. CONSTITUTION:An aromatic carboxylic acid is produced by the reaction of an aromatic compound (monocyclic, polycyclic or condensed ring compound) having substitutable H at the nucleus with CO2 in the presence of a Pd catalyst. The Pd catalyst is an organic or inorganic acid salt of Pd or a Pd complex, etc., especially a 2-4C aliphatic monocarboxylic acid salt of Pd. A beta-diketone complex salt of Pd can also be used as the catalyst, and it may be added to the reaction system or a Pd compound and beta-diketone may be added separately to the system to form a beta-diketone complex salt in the reaction system. The amount of the catalyst is preferably >=1X10<-5>g in terms of metallic Pd per 1g- mol of the starting substance. The reaction is carried out at 70-250 deg.C for 30min-50hr.

Description

DETAILED DESCRIPTION OF THE INVENTION a. Field of Industrial Application 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, Jour
nal of Chemical 5ocie-ty,
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 Journal of Chemi.
calSociety, Chemical Comm
132 (1982) describes a method of obtaining carboxylic anhydride by further adding 1,2-dibromoethane to the same method as the previous example.

Furthermore, a method using carbon dioxide gas as a carboxylating agent is
In research as a model of the photosynthetic system of plants, various types of inspections have been added using light. As such a method,
For example, Nature, Vol. 275, p. 301, describes electron carriers such as pyrene or perylene and 1°4-
It has been confirmed that formic acid is produced when electron-accepting substances such as dicyanobenzene and 9.10-dicyanoanthra7ane are irradiated with a mercury arc in a polar solvent such as acetonitrile with water, and carbon dioxide gas is blown in for 8 hours. There is.

Also Journal Chemical 5ociet
y, Chemi-cal Communicatio
According to p.
O2 pressure 4kl? When a Pyrex container was irradiated with a mercury lamp at a distance of 7CIn and reacted for 14 hours at room temperature, the carboxylic acid was 33% compared to the reacted phenanthrene.
It is disclosed that it was obtained in a yield of ~55%. In this case, the small amount of water had no effect on the reaction, and this reaction was 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 industrial costs and handling. - The method using carbon dioxide gas using a force tip has the drawback of increasing the manufacturing and operating costs of the light irradiation container.

Structure of the CO Invention Therefore, the present inventors conducted extensive research on a method for carboxylating an aromatic compound and CO2 in the presence of a catalyst without using light, and as a result, they arrived at the present invention.

That is, the present invention is a method for producing a corresponding aromatic carboxylic acid, which is characterized by reacting an aromatic compound having at least one substitutable hydrogen atom in its nuclear carbon with carbon dioxide gas in the presence of a palladium catalyst.

According to the method of the present invention, without using light or the like,
By introducing carbon dioxide gas into the aromatic nucleus in one step, carboxylation can be performed to obtain the corresponding aromatic benzenecarboxylic acid, and its industrial significance is very old.

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.

Moreover, they may have substituents that do not inhibit the reaction. Examples of such items include the following.

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

Terphenyl, quaterphenyl, substituted derivatives thereof, etc. (C) Condensed ring aromatic compounds such as naphthalene, anthracene, phenanthrene and substituted derivatives thereof, etc. Substituents constituting substituted derivatives of these various aromatic compounds include, for example, the following ( , ) ~ (+1 can be given.

(-) an alkyl group or a cycloalkyl group such as a methyl group, an ethyl group, an n- or 1so-butyl group, n
, 1so- or ter-butyl group.

Cyclohexyl group, etc. (b) Hydroxyalkyl group, e.g. hydroxymethyl group, hydroxyethyl group, etc. (C) Alkoxy group, e.g. methoxy group, ethoxy group, etc. (d) Carboxyl group or its ester, e.g. -C
OOH, -COOCH,, -COOC,, H5, -C
OOC,,H,.

-COOC, H, etc. (,) Cyano group (f) Nitro group (g) Formyl group (h) Halogen such as fluorine, chlorine, etc. (i) Acyl group such as acetyl group, globionyl group, benzoyl group, etc. (j) The above The hydrogen of the alkyl group of (,) is
) to (h) A group substituted with at least one of the substituents mentioned above.Specific examples of the aromatic compounds used in the present invention are as follows.

(]) Examples of aromatic compounds: benzene, toluene, xylene (0゜m+p)
+ Ethylbenzene, cumene, trimethylbenzenes,
Tetramethylbenzene, naphthalene, α- or β-methylnaphthalene, dimethylnaphthalenes, eternapthalene, anthracene, phenanthrene, piphenyl.

4-methylbiphenyl, 3-methylbiphenyl+ 3+
3”/methyl biphenyl, etc. (2) Aromatic h carboxylic acids or their esters such as benzoic acid, methyl benzoate, ethyl benzoate, toluic acid (o, m, p) r) methyl toluate (o+ m
+p) +α-naphthoic acid) β-naphthoic acid, methyl-α-naphthoic acid, methyl-β-naphthoic acid, α-
Methyl naphthoate, methyl β-su7toate, ether α-naphthoate, ethyl β-naphthoate, zynphenylmonocarboxylic acid (2-,3-alternatively 4-) or its methyl,
Ethyl, propyl, butyl esters, etc. (3) Examples of aromatic ethers: evaanisole, diphenyl ether.

diphenylethercarboxylic M + diphenyletherdicarboxylic acid, l,2-diphenoxyethane, formula HO
OC-〇-o-cH2-CH2-0-C> or esters thereof, etc. (4) Examples of other aromatic compounds, t hamonochlorobenzene, dichlorobenzene, chlornaphthalene, benzonitrile.

As the palladium catalyst used in the present invention, organic and inorganic acid salts of palladium are used, such as tolnitrile, cyanonaphthalene, nitrohenzene, and acetophenone. The palladium salt used is generally a divalent salt. However, zero-valent palladium complexes or tetravalent salts can be used as well.

Examples of such palladium organic salts include palladium carboxylate and β-diketone complex salts.

Keto ester complex salt power is a blessing to this.

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-o bonded to the palladium oxide may be an alkyl group, a cycloalkyl group, an aryl group, or a substituent thereto that does not inhibit the reaction (for example, the starting material The above (shown as a substituted derivative group of an aromatic compound)
, ) to (i) groups) can be mentioned.

Preferred among these are aliphatic monocarboxylic acids having 2 to 2 degrees of carbon atoms, aliphatic di- or tricarboxylic acids having 3 to 2 degrees of carbon atoms, alicyclic carboxylic acids having 6 to 2 degrees of carbon atoms, and benzene. These include mono- or di-carboxylic acids, naphthalene mono- or di-carboxylic acids, and specific examples include acetic acid,
Propionic acid, iso- or n-butyric acid, caproic acid.

Malonic acid, succinic acid, adipic acid, cyclohexanecarboxylic acid, naphthenic acid, benzoic acid, toluic acid, α-naphthoic acid, β-naphthoic acid, etc., and particularly preferred are aliphatic monocarboxylic acids having 2 to 4 carbon atoms. It is an acid.

In the present invention, a β-diketone complex salt of palladium is also used as a catalyst. 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.

The β-diketone that can form the palladium β-diketone complex salt of the catalyst in the method of the present invention may be any β-diketone as long as it can form the general formula. Examples of such substances include acetylacetone, gropionylacetone, and butylacetone.

Inbutyryl acetone, caproyl acetone.

C-methylacetylacetone, tetraacetylethane,
Benzoylacetone, dibenzoylmethane, trifluoroacetylacetone, hexafluoroacetylacetone, benzoyltrifluoroacetone, β-naphthoyltrifluoroacetone, acetoacetic acid, acetoacetic ester.

Examples include trifluoroacetoacetic acid and trifluoroacetoacetic acid ester.

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

Examples include hydroxides. Examples of palladium inorganic salts include nitrates.

Examples include 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. In general, l as cibaradium metal per gram mole of starting material.
Xl0 Durham atom or more is preferable, and the upper limit thereof is not particularly limited, but is limited 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 products, it can be purified and reused.

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 outside the reaction yarn and does not adversely affect the reaction.

When using a solvent, the following are preferred.

(1) Carboxylic acids such as acetic acid, propionic acid, butyric acid, benzoic acid, etc. (11) Carboxylic acid anhydrides such as acetic anhydride, propionic anhydride, butyric anhydride, phthalic anhydride, succinic anhydride, etc. (tii) Carboxylic acid esters For example, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, methyl butyrate, ethyl butyrate, methyl benzoate, ethyl benzoate, etc. (1v) Ethers, such as ethyl ether, tetrahydrofuran, dioxane, glyme, diglyme, etc. (v) ) Ketones such as aceto/, methyl ethyl ketone, methyl intyl ketone, etc. (vD Alcohols such as methanol, ethanol, butanol, impropatol, etc.) Nitriles such as acetonitrile, propionitrile, etc. (vlil) Organic halides such as chloroform , carbon tetrachloride, ethylene dichloride, perchloroethylene, etc., are merely examples, and are not limited to these.Furthermore, the above-mentioned media 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 greater than or equal to the fluidity of the reaction system (including slurry).

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 50 to 300°C, preferably 70 to 250°C, and the reaction time varies depending on the reaction conditions, but is preferably 10 minutes to 100 hours, preferably 30 minutes to 50 hours. .

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.

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.

Examples 1 to 4 Aromatic compounds shown in the table below and palladium nitrate [Pd(N
O3)2.2H20) is charged, and carbon dioxide (CO2) is introduced at room temperature to 30 kg/cil.

Thereafter, the reaction was carried out at a temperature of 150° C. for 20 hours, and the obtained product was analyzed, and the following results were obtained.

Claims (1)

[Claims] 1. A method for producing a corresponding aromatic carboxylic acid, which comprises reacting an aromatic compound having at least one substitutable hydrogen atom in its nuclear carbon with carbon dioxide gas in the presence of a palladium catalyst.