JPH0780789B2 - Dimerization method of aromatic halogen compounds - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a biaryl compound by dehalogenating and dimerizing an aromatic halogen compound.

[Conventional technology]

Biaryl compounds obtained by dimerization of aromatic compounds are useful as various industrial raw materials.
Alkali metal salt of 3,4,3 ', 4'-biphenyltetracarboxylic acid is a useful material as a raw material for producing a heat resistant polyimide resin. Conventionally, as a method for producing a biphenyl compound by dehalogenating an aromatic halogen compound, for example, a method of dehalogenating dimerization in the presence of a catalyst supporting metal palladium in an aqueous alkali hydroxide solution and methanol (J .Am.Chem.Soc.71 776 (1949), JPB 59
-14015), and as a modification of this method, a method using polyhydric alcohol or formaldehyde instead of methanol (JP-A-62-26238), a method using formic acid or formate salt (Synthesis communications 538, (1978). ,
JP-A-61-137838 and JP-A-61-167642), a method using carbon monoxide (JP-A-61-293932) and the like are known. However, these known methods have a problem that the yield of the desired biphenyl compound is low because the conversion rate of the aromatic halogen compound is insufficient or a large amount of the dehalogenated aromatic compound is by-produced. ,
No satisfactory method has been found for obtaining high yields of biphenyl compounds.

[Problems to be Solved by the Invention]

In view of the above circumstances, the present inventors have conducted studies to obtain a target biphenyl compound in a high yield, and as a result, in the above-mentioned known method, chloroform may be used in place of methanol. Found a patent application. (Japanese Patent Application No. 62-103982 (Japanese Patent Laid-Open No. 63-267735)
As a result of further studies on the above method, it was found that, when chloroform is used, the yield of the target compound is further improved by further adding an amine.

That is, the present invention aims to provide a method capable of producing a high yield of biaryl compounds by dehalogenating an aromatic halogen compound and dimerizing it.

[Means for Solving the Problems]

The gist of the present invention is to dehalogenate an aromatic compound having at least one halogen atom in an aromatic nucleus carbon in an aqueous medium in the presence of a platinum metal catalyst, an alkali metal or alkaline earth metal compound, chloroform and an amine. And a dehalogenation dimerization method for aromatic halogen compounds.

The present invention will be described in detail below.

As a starting material in the method of the present invention, an aromatic compound having at least one halogen atom in the aromatic nucleus carbon is used.

As the at least one halogen atom in the aromatic nucleus carbon, chlorine, bromine and iodine are usually mentioned. Among them, bromine and chlorine are preferable. The number of halogen atoms bonded to the aromatic nucleus carbon can be 1 to 6, but preferably 1 to 3
When there are two or more halogen atoms, these halogen atoms may be the same or different.

The nuclear carbon of this aromatic halogen compound may be substituted with a substituent other than a halogen atom that does not adversely affect the dehalogenation dimerization reaction, but has a substituent on the adjacent carbon of the aromatic nuclear carbon having a halogen atom. In this case, the yield of the target dimeric biaryl compound tends to decrease.

Specific examples of the early aromatic compound used in the present invention include, for example, chlorobenzene, promobenzene, p-chlorobromobenzene, p-chlorodiphenyl, p-chlorophenol, p-chloroanisole, p-chlorophenetol, p. -Chlorobenzamide, p-chloroaniline, p-chlorobenzophenone, p-chloroacetophenone, p-chlorozonzonitrile, p-chlorobenzenesulfonic acid sodium salt, α-chloronaphthalene, 4-
Chloro-ortho-xylene, p-chloro (or bromo) benzoic acid, m-chloro (or bromo) benzoic acid, 4-chloro (or bromo) orthophthalic acid, 4-chloro (or bromo) orthophthalic acid alkali metal salt, and 4 Examples include 5,5-dichloro (or bromo) phthalic acid. In particular,
4-chloro (or bromo) orthophthalic acid, 4-chloro (or bromo) orthophthalic acid alkali metal salt, 4-
4-Halophthalic acids such as chloro (or bromo) orthophthalic anhydride, 4,5-dichloro (or bromo) phthalic acid, and p-chloro (or bromo) benzoic acid, m-chloro (or bromo) benzoic acid, etc. Particularly preferred are the halobenzoic acids of.

In the method of the present invention, these aromatic halogen compounds are usually used as a single kind, but if necessary, a mixture of different aromatic halogen compounds can be used.

Examples of the central metal of the white metal metal catalyst used in the present invention include palladium, rhodium, ruthenium, platinum, iridium, etc. Among them, palladium and rhodium are preferable.

These platinum group metal catalysts include inorganic acid salts such as halides, nitrates and sulfates, inducing acid salts such as acetates, benzoates and phthalates, chelate salts including β-diketones such as acetylacetone, and simple substances. Used as. Above all,
Activated carbon, silica, alumina, silica-alumina, zeolite, titanium oxide, magnesia, diatomaceous earth, graphite, asbestos, ion-exchange resin, barium carbonate, calcium carbonate, etc. are preferably supported on the carrier, and particularly supported on activated carbon. Catalysts are preferred. In these supported metal catalysts, it is preferable that the metal is usually supported on the carrier in an amount of 0.1 to 20% by weight, particularly 0.5 to 10% by weight. The amount of the platinum group metal catalyst used is usually 100 to 0.001 mmol, preferably 30 to 0.01 mmol, in terms of metal atom, based on 1 mol of the aromatic halogen compound.

On the other hand, as the alkali metal compound or the alkaline earth metal compound, an inorganic acid salt of an alkali metal or an alkaline earth metal such as carbonic acid, nitric acid, phosphoric acid or boric acid, an organic acid salt such as acetic acid, a hydroxide, and an alkoxide. And the like.

Particularly preferred specific examples include hydroxides such as lithium hydroxide, sodium hydroxide, potassium hydroxide, magnesium hydroxide, calcium hydroxide and barium hydroxide, carbonates such as sodium carbonate, potassium carbonate and sodium hydrogen carbonate, sodium. Alkoxides such as methoxide, sodium ethoxide, potassium tert-butyrate, etc., but carbonates are preferable because hydroxides may have a slightly lower reaction yield than hydroxides.

The amount of these alkali metal compounds or alkaline earth metal compounds used is not particularly limited and varies depending on the number of halogen atoms contained in the starting aromatic halogen compound and the presence of an acidic substituent such as a carboxyl group. Except for the equivalent amount of acidic substituent, it is 3 to the nuclear halogen.
20 equivalents are preferable, and 6 to 15 equivalents are particularly preferable.

The present invention, in the reaction of dimerizing an aromatic halogen compound in the presence of a platinum group metal catalyst and an alkali metal compound or an alkaline earth metal compound as described above, it is essential that chloroform and amine are further present. Is a requirement.

The amount of chloroform used is not particularly limited, and is 0. per atom of the nuclear halogen of the aromatic halogen compound.
It is about 1 to 20 mol, but from the economical aspect, it is sufficient to use the minimum necessary amount that can industrially obtain a biphenyl compound in a good yield. The amount used is 1 atom of nuclear halogen of an aromatic halogen compound. , 0.1 to 1.5 mol, preferably 0.1 to 1.5 mol
It is 1.0 mol.

As a method for allowing chloroform to exist in the reaction system, a method in which liquid chloroform is added to the reaction system from the beginning in a necessary amount, a method in which liquid chloroform is intermittently or continuously supplied while sufficiently stirring the reaction solution, etc. However, in order to effectively carry out the present invention, it is preferable to supply chloroform intermittently or continuously. In such a case, the supply rate of chloroform is selected from the range of 0.01 to 1.0 mol, preferably 0.01 to 0.1 mol, per 1 atom of the nuclear halogen per unit time.

On the other hand, as another method of allowing chloroform to exist in the reaction system, it is also preferable to pass gaseous chloroform through the reaction system.

In this case, if necessary, replace chloroform with nitrogen, argon,
You may use it, mixing with carrier gas, such as carbon monoxide. The concentration of chloroform in the mixed gas is not particularly limited, but usually 1% by volume or more is suitable. The gas supply rate is not uniquely determined by the chloroform concentration, but may be 0.01 to 1.0 mol, preferably 0.01 to 0.1 mol, per 1 hour of the nuclear halogen per unit time. It is about 1 to 100 l / hr (converted to the standard state) per one.

On the other hand, as the amine used in the present invention, methylamine,
Ethylamine, n-propylamine, isopropylamine, n-butylamine, n-amylamine, n-hexylamine, n-octylamine, n-laurylamine,
Hexamethylenediamine, ethanolamine, allylamine, paraaminobenzoic acid, paraaminobenzoic acid methyl ester, paraaminobenzoic acid sodium salt, primary amines such as glycine, secondary amines such as di-n-propylamine and di-n-butylamine, Examples thereof include tertiary amines such as tri-n-propylamine and tri-n-butylamine.

Of these, primary amines are preferable, and C ₁ such as methylamine, ethylamine, n-propylamine, isopropylamine, n-butylamine, n-hexylamine, n-octylamine, and n-laurylamine is more preferable.
To C ₁₂ alkylamines, with C _{1 to} C ₄ alkylamines being particularly preferred.

The amount of amine used is 0.1 to 100 per atomic weight of platinum group metal.
The molar amount is preferably 0.5 to 20 mol. Outside the above range, the yield of the biphenyl compound is low, and the effects of the present invention cannot be sufficiently exhibited.

In the reaction of the present invention, water is used alone or an aqueous solvent mainly containing water and inert to the reaction, for example, ethers such as tetrahydrofuran and dioxane is used as a solvent. In this case, the amount of the solvent used is usually about 0.1 to 50 times the volume of the aromatic halogen compound.

The reaction temperature of the present invention is usually 50 to 200 ° C, preferably 100 to 200 ° C.
The reaction pressure is usually 200 kg / cm ² , and the reaction pressure is 150 ° C.
It is preferably normal pressure to 100 kg / cm ² .

The method of the present invention can be performed in a batch system, a semi-batch system, or a continuous system.

The platinum group metal catalyst used in the reaction is separated and recovered from the reaction solution by a method generally used in the past, such as an extraction method, a crystallization method or a reduction method. When a supported metal catalyst is used, it can be easily separated and recovered and can be used again in the dehalogenation dimerization reaction.

The biaryl compounds obtained in the present invention are separated and obtained from the reaction solution by an evaporation method, a distillation method, a crystallization method, an acid precipitation method or the like according to their physical properties.

〔Example〕

Next, the present invention will be described in more detail by way of examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded.

Examples 1 to 8 In a stainless steel electromagnetic induction rotary autoclave of Content 1 equipped with a vaporizer and a gas introduction pipe, 2% by weight.
Palladium carbon (9 g) and demineralized water (250 ml) were previously charged with 4-chloroorthophthalic acid monosodium salt (hereinafter referred to as 4-CPA salt) 232.9 mmol, 3-chloroorthophthalic acid monosodium salt 14.8 mmol, 4,5-dichlorophthalic acid monosodium salt. A sodium salt (hereinafter abbreviated as 4,5-DCPA salt) 14.5 mmol, 3,4-dichlorophthalic acid monosodium salt 15.6 mmol, orthophthalic acid monosodium salt 76.6 mmol and an aqueous solution in which 20 g of sodium hydroxide is dissolved, 100 ml of demineralized water, 100 g of the amine shown in Table 1 and 100 g of sodium hydroxide were charged. While stirring this mixture at 750 rpm, nitrogen was introduced from the bottom of the autoclave 1 through a vaporizer and a gas introduction pipe to a pressure of 5 kg / cm ² · G,
Further, it was circulated at a flow rate of 15 Nl / Hr.

When the temperature of the autoclave was raised to 120 ° C and the temperature of the vaporizer to 100 ° C, chloroform was sent to the vaporizer at 2.4 ml / hr and a mixed gas of chloroform / nitrogen was supplied into the autoclave through a gas introduction pipe. Stop supplying chloroform in 8 hours,
The reaction was stopped.

When the reaction solution was analyzed by high performance liquid chromatography, the sodium salt of orthophthalic acid produced by dehalogenation and the desired sodium salt of 3,4,3 ', 4'-biphenyltetracarboxylic acid (hereinafter abbreviated as S-BTC salt) were obtained. Was being generated.

The results are shown in Table-1.

Comparative Example-1 The reaction was performed in the same manner as in Example-1 except that amine was not used.

The results are shown in Table-1.

ADVANTAGES OF THE INVENTION According to the present invention, a method for dehalogenating an aromatic halogen compound in an aqueous medium in the presence of a platinum group metal catalyst, an alkali metal compound or an alkaline earth metal compound and chloroform, By the presence of the above, a dimer of an aromatic compound can be obtained with high yield and good selectivity, which is an industrially extremely advantageous method.

Claims (1)

[Claims] 1. Dehalogenation of an aromatic compound having at least one halogen atom on an aromatic nucleus carbon in an aqueous medium in the presence of a white metal metal catalyst, an alkali metal compound or an alkaline earth metal compound, chloroform and an amine. A dehalogenation dimerization method for an aromatic halogen compound, which comprises quantifying.