JPS63267735A - Dimerization of aromatic halogen compound - Google Patents

Abstract

PURPOSE:To obtain a dimer in high yield and in excellent selectivity, by dimerizing an aromatic compound containing a halogen atom. on an aromatic carbon through dehalogenation in the presence of a platinum group metallic catalyst, an alkaline (earth) metallic compound and chloroform in a aqueous medium. CONSTITUTION:An aromatic compound (e.g. m-chlorobenzoic acid) containing a halogen atom. in the nucleus is dimerized through dehalogenation in the presence of a platinum group metallic catalyst (preferably Pd or Rh), an alkaline (earth) metallic compound (preferably hydroxide) and chloroform in an aqueous medium (e.g. water-ether) at 50-200 deg.C under normal pressure - 100kg/cm<2> to give a dimer (e.g. sodium biphenyl-3,3'-dicarboxylate). The catalyst can be separated, recovered from the reaction solution and reused. The amount of chloroform used is preferably 1-2,000mol. based on 1g atom. platinum group metal.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing biaryl compounds by dehalogenating and dimerizing aromatic halogen compounds.

[Conventional technology]

Biaryl compounds obtained by dimerization of aromatic compounds are useful as various industrial raw materials.For example, alkali metal salts of y, lI, s', a'-biphenyltetracarboxylic acid are used in the production of heat-resistant polyimide resins. It is a useful substance as a raw material for industrial use. Conventionally, as a method for producing biphenyl compounds by dehalogenating and dimerizing aromatic halogen compounds.

For example, a method in which metal palladium is supported in an aqueous alkali hydroxide solution and dehalogenated and dimerized in the presence of a nine-catalyst catalyst and methanol (J, Am, Chem.

SOo, 7/ Kuku b (iqeq), special public school 1977-1
'101! No.) etc. are known. however.

These known methods have the problem of producing a large amount of dehalogenated aromatic compounds over a long period of time, resulting in a low yield of the desired biphenyl compound. The challenge is to suppress it.

[Problem that the invention seeks to solve]

The present invention aims to provide a method capable of producing biaryl compounds in high yield by dehalogenating and dimerizing aromatic halogen compounds.

[A precautionary measure to resolve the problem]

The gist of the present invention is to dehalogenate and dimerize an aromatic compound having at least 7 halogen atoms in an aqueous medium in the presence of a platinum metal catalyst, an alkali metal or alkaline earth metal compound, and chloroform. The present invention relates to a method for dehalogenating and dimerizing aromatic halogenated compounds.

The present invention will be explained in detail below.

Aromatic compounds having at least 7 halogen atoms on the aromatic carbon are used as starting materials in the process of the invention.

Examples of the at least one halogen atom in the aromatic carbon include chlorine, bromine, and iodine, with bromine and chlorine being preferred.

The number of halogen atoms bonded to the aromatic nuclear carbon XK can be 1-6, but preferably 7 to 3.

When there is one or more halogen atoms, these halogen atoms may be the same or different from each other.

The core carbon of this aromatic halogen compound may be substituted with a substituent other than a halogen atom that does not adversely affect the dehalogen dimerization reaction, but substituents may When it has, the yield of the target dimeric biaryl compound tends to decrease.

Specific examples of the aromatic compounds used in the present invention include chlorobenzene, bromobenzene, 1p-chlorobromobenzene, p-/lorodiphenyl, p-chlorophenol-p-chloroanisole, and p-chloroanisole.

p-/loropenzamide, p-chloroaniline.

p-/lolobenzophenone, p-/loloacetophenone, p-chlorobenzonitrile, p-/lolobenzenesulfonic acid-/-) IJum salt, α-chloronaphthalene, I
I-Chloroorne xylene.

Archlorobenzoic acid, II-chloroorthophthal 11,
Examples include alkali metal salts of 41-chloroorthophthalic acid and da,j-dichlorophthalic acid, but the aromatic halogen compounds used in the present invention are not limited to the above.

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

The central metal of the platinum metal catalyst used in the present invention is palladium, rhodium, and ruthenium.

Examples include platinum and iridium, with palladium and rhodium being particularly preferred.

These platinum group metal catalysts are halides.

It is used in inorganic acid salts such as nitrates and sulfates, organic salts such as acetates, benzoates, and phthalates, chelate salts containing β-diketones such as acetylacetone, and as a simple substance.

Among these, the metals are activated carbon, silica, alumina, and silica alumina.

Zeolite, titanium oxide, magnesia, diatomaceous earth.

Graphite, asbestos, ion exchange resin.

A catalyst supported on a carrier such as barium carbonate or calcium carbonate is preferred, and a catalyst supported on activated carbon is particularly preferred. In these supported metal catalysts, the metal is usually 0.0% relative to the support. /-ko01jLit.

Especially 0. It is preferable that j −/0 weight tSS is supported. The amount of platinum group metal catalyst used is usually 100 to 0.0 in terms of metal atoms per mol of aromatic halogen compound.
0/mmol, preferably 30 to 0.07 mmol.

In the present invention, it is necessary that an alkali metal compound or an alkaline earth metal compound be present in the reaction system. Examples of alkali metal compounds or alkaline earth metal compounds include alkali metal or alkaline earth metal carbonic acid, nitric acid,
phosphoric acid.

Examples include inorganic acid salts such as boric acid, organic acid salts such as acetic acid, hydroxides, and alkoxides.

Particularly preferred examples include hydroxides such as lithium hydroxide, sodium hydroxide, potassium hydroxide, magnesium hydroxide, calcium hydroxide, and barium hydroxide, sodium carbonate, and potassium carbonate.

These include carbonates such as sodium bicarbonate, alkoxides such as sodium methoxide, sodium ethoxide, and potassium tert-glylate, but carbonates have a slightly lower reaction yield than hydroxides, so hydroxide more preferable.

The amount of these alkali metal compounds and alkaline earth metal compounds to be used varies depending on the number of halogen atoms contained in the aromatic halogen compound that is the starting material and the presence of acidic substituents such as carboxyl groups, and is not particularly limited. is 0.07 to 100 per mole of aromatic halogen compound
mol, preferably 0.1 to 20 mol.

The present invention is directed to the addition of chloroform to the reaction of 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. is an essential requirement.

The amount of chloroform present in the dimorization reaction system is determined by the amount of platinum group metal regardless of its supply method. Atomic analysis o,
ot to 000 moles, particularly 7 to 2000 moles are preferred. If the amount of chloroform is outside the above range, the yield of the biaryl compound will decrease, which is not preferred.

There are no specific methods for introducing chloroform into the reaction system; for example, chloroform in the range described above may be added to one reaction system from the beginning, or one reaction may be started and then the reaction solution may be sufficiently stirred. However, chloroform may be added intermittently and light may be added continuously to maintain the above range. In this case, the total amount of chloroform used is preferably about 0.7 to 20 moles per 7 moles of the aromatic halogen compound.

On the other hand, as a method for making chloroform exist in the reaction system, gaseous chloroform can also be passed through the reaction system. In this case, you need chloroform with nitrogen,
It may be used in combination with a carrier gas such as argon or carbon oxide. The concentration of chloroform in the mixed gas is not particularly limited, and is usually preferably S volume of 1 tcs or more. Although the gas supply rate is not necessarily determined by the concentration of chloroform, it is approximately 0 to 0 g Ot/hr (converted to standard conditions) per 1 reaction solution.

In addition, in the reaction of the present invention, the water content is 211 or water is the main component, and the solvent inert to the reaction is 1. For example, tetrahydrofuran,
An aqueous medium comprising ethers such as dioxane is used as the solvent. The amount of solvent used in this case is usually 0.1 to the aromatic halogen compound. / ~ jO capacity is about twice as large.

The reaction temperature of the present invention is usually 0 to 300'C.

Preferably! 0-200° C., and the primary reaction pressure is usually normal pressure to λ(7t) kg/cI1. Preferably normal pressure to 100 degrees Celsius.

The method of the present invention can be carried out in a batch, semi-batch or continuous manner.

The platinum group metal catalyst used in the reaction is separated and recovered from the reaction solution by conventional methods such as extraction, crystallization, or reduction.

When a supported metal catalyst is used, it can be easily separated and recovered by filtration and used again in the dehalogenation dilenation reaction.

Obtained according to the present invention. Biaryl compounds.

Depending on its physical properties, it is separated from the reaction solution by evaporation, distillation, crystallization, acid precipitation, etc.

〔Example〕

Next, the present invention will be explained in more detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the scope thereof.

Example - / Internal volume 100 with reflux condenser, stirrer 1 dropping funnel
-Methachlorobenzoic acid (
(hereinafter abbreviated as m-0BA) Ko, O? , sodium hydroxide l
,, Of, water 20- and 2% by weight /<Radium Carbon (manufactured by Nippon Engelhard) Q, Co? was charged and heated to reflux while stirring. Then, from the dropping funnel,
0.1 jwt of chloroform was added intermittently every j minutes. After adding a total of 4 Iwt of chloroform, refluxing was continued for 75 minutes. After the reaction, the reaction solution was analyzed by high-performance liquid chromatography.

Dehalogenated benzoic acid sodium salt and the desired biphenyl-3,3'-dicarboxylic acid sodium salt (hereinafter referred to as B
(abbreviated as DO salt) was produced.

The results are shown in Table-7.

Comparative Example 7 The same procedure as Example 7 was carried out except that chloroform was not added. The results are shown in 9-/.

Comparative Example-1 Add methanol 2- to chloroform instead of i, s
The same procedure as Example 7 was carried out except that the reaction was carried out for a certain period of time. The results are shown in the ticket -/.

Table -l Hayashi BDOjmfl Sawahan was turned into a furnace and kneed. Bm (mol) A / (J (J Example - 300-volume glass box black flask equipped with reflux condenser, stirrer, and gas inlet tube) Chlororunphthalic acid monosodium salt 76.3 Millimoles (hereinafter ≠ −
0PA salt omitted. ), J-chloroorthophthalic acid monosodium salt/11.1 mmol, dichloroorthophthalic acid monosodium salt 9.7 mmol, orthophthalic acid monosodium salt a, ri mmol, sodium hydroxide lI&), and Prepare water/AOd.

An aqueous solution of crude halogenated orthophthalate and sodium hydroxide was prepared. Next, double t palladium carbon, 7fP was added, heated to reflux while stirring under normal pressure, and the JjC was saturated with yte/roloform vapor from the gas inlet tube, and nitrogen gas was added into the aqueous solution at a flow rate of 700 dl. Since it is not supplied continuously, it can be converted into tSS time. After the reaction, high-performance liquid chromatography analysis revealed that 1. 9-orthophthalic acid sodium salt and the desired 3. #,3',II'-biphenyltetracarboxylic acid sodium salt (hereinafter abbreviated as 5-BTO salt)
Have a friend. The results are shown in Table-C.

Comparative Example 3 The procedure was the same as in Example 3, except that instead of supplying the dichloroform-nitrogen mixed gas through the gas inlet tube, methanol/Am was added and the mixture was allowed to cook for an external time.

The results are shown in Table-λ.

Table - [Effect] According to the present invention, the presence of chloroform in the method for dehalogenating and dimerizing an aromatic halogen compound in an aqueous medium in the presence of a platinum group metal catalyst and an alkali metal compound or an alkaline earth metal compound. By doing so, a dimer of an aromatic compound can be obtained with high yield and good selectivity, and is an extremely advantageous method industrially.

Applicant: Sanrishisei Kogyo Co., Ltd. Agent Patent attorney Long diameter - (7 others)

Claims (1)

[Claims] (1) Dehalogenating and dimerizing an aromatic compound having at least one halogen atom in the aromatic carbon in an aqueous medium in the presence of a platinum metal catalyst, an alkali metal compound or an alkaline earth metal compound, and chloroform. A method for dehalogenating and dimerizing aromatic halogenated compounds.