JPS6122045A - Method for producing biphenyltetracarboxylic acid - Google Patents

Abstract

PURPOSE:To obtain the titled compound useful as a raw material of highly heat- resistant polymer, in high yield, under mild condition, with a few reaction steps, by coupling an easily available Grignard reagent in the presence of copper chloride, and oxidizing the product with an oxidizing agent. CONSTITUTION:The Grignard reagent of formula I (X is halogen) is subjected to the coupling reaction at 0-100 deg.C, in the presence of copper chloride in an organic solvent, preferably diethyl ether, tetrahydrofuran, etc. and the obtained tetramethylbiphenyl of formula II is oxidized in the presence of an oxidizing agent to obtain the objective compound of formula III. The oxidizing agent is e.g. potassium permanganate, potassium bichromate, etc., and its amount is preferably >=4 equivalent. The Grignard reagent can be prepared by reacting 1 equivalent of a holo-oxylene with 1-1.05 equivalent of magnesium by conventional method.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a method for producing biphenyltetracarboxylic acid.

[Background of the invention]

Conventionally, several methods have been known for producing tetramethylbiphenyl and hinibiphenyltetracarboxylic acid. However, these conventional techniques have poor yields and lack reaction selectivity. There are many problems, including the risk of explosion.

The following method is known as a method for synthesizing tetramethylbiphenyl, but it involves various problems.

For example, as typified by Japanese Patent Publication No. 50-31149,
A method for dehydrogenating ortho-xylene under oxygen pressure in the presence of an organic acid salt of palladium and ethylenediaminetetraacetic acid, as typified by JP-A-55-79324°. In the presence of
A method of coupling under oxygen pressure is known. However, these methods have many problems, such as poor yields, lack of selectivity in the reaction, resulting in the production of many isomers, the need for special synthesis equipment, and the risk of explosion. In addition, a method in which iodoxylene and copper powder interact (Utma
n reaction) has been known for a long time, but this also has the drawback of poor yield.

Similar problems also exist in the method for synthesizing biphenyltetracarboxylic acid. For example, (1) Dimethyl orthophthalate is dehydrogenated by adding β-diketone and/or ethylenediaminetetraacetic acid under oxygen pressure in the presence of an organic acid salt of palladium, and then hydrolyzed with acid to produce it. Method (see Japanese Patent Publication No. 50-31148), ■
A method for producing ortho-xylene by dehydrogenating it in the presence of an organic acid salt of palladium and ethylenediaminetetraacetic acid under oxygen pressure, and then oxidizing it in the liquid phase.
31149), (2) A method of coupling 4-halogenorthophthalate by heating it in an aqueous alkali hydroxide solution in the presence of metal palladium and a small amount of methanol (Japanese Patent Laid-Open No. 55-20705) Reference), ■
An orthophthalic acid ester and an organic palladium salt, 1.
A method of synthesis by oxidative coupling under pressurized oxygen in the presence of 10-phenanthroline and/or α,α'-bipyridyl (Japanese Patent Application Laid-open No. 153747/1983) is known. Among these, ■, ■, and ■ require special equipment for the reaction under pressurized oxygen, which not only poses the risk of explosion, but also has poor yields, a large number of isomers, and no selectivity. There is a problem with this. (2) reacts under mild conditions, but has the problem of extremely poor yield.

[Object of the invention]

The object of the present invention is to cure raw materials for highly heat-resistant polymers such as polyimide and epoxy resins with high purity, yield, and mild conditions in a relatively small number of steps without the problems of the above-mentioned conventional techniques. An object of the present invention is to provide a method for producing ≠phenyltetracarboxylic acid, which is extremely useful as an agent.

[Summary of the invention]

The biphenyltetracarboxylic acid of the present invention is obtained by coupling a Grignard reagent represented by the general formula (X represents a halogen) in the presence of copper chloride to obtain tetramethylbiphenyl, which is then oxidized in the presence of an oxidizing agent. It is characterized by the fact that it can be obtained by

A representative method of the invention is as follows.

(X is a halogen) is reacted with magnesium to obtain the Grignard reagent.

(2) Coupling the above Grinyaya reagent in the presence of copper chloride to obtain the tetramethylbiphenyl shown.

■ Oxidation of tetramethylbiphenyl in the presence of an oxidizing agent yields phenyltetracarboxylic acid.

The no-rogen group of the no-ro-orthoxylene used in the present invention is preferably a chloro, bromo, or iodo group. A Grignard reagent obtained by reacting 1 equivalent of this haloorthoxylene with 1 to 1.05 equivalents of magnesium by a conventional method,
1 to 1.5 equivalents of copper chloride, dibutyl ether, tetrahydrofurine, dibutyl ether, toluene, benine in an organic solvent at a reaction temperature of 0 to 100C,
After 3 hours of reaction, the coupling results in tetramethylbiphenyl. After the reaction is complete, it can be purified by conventional methods such as vacuum distillation. .

By oxidizing the obtained tetramethylbiphenyl with 4 equivalents or more of an oxidizing agent, such as potassium percarnate, potassium dichromate, nitric acid, etc., biphenyltetracarboxylic acid can be obtained in a yield of 80% or more.

[Embodiments of the invention]

Example 1 In 72 mt of tetrahydrofuran, a tetrahydrofuran solution of 4-promomagnesium-0-xylene obtained by a conventional method from 14 g of metallic magnesium and 74 g of 4-promo-0-xylene was cooled to 5 to 10C. Thereafter, 47.3 g of copper chloride was added and stirred for about 1 hour to complete the reaction. After washing the reactant with water and distributing the precipitated copper, the solvent was distilled off to remove the remaining residue.

Distilled under reduced pressure under the conditions of 151C and 10wHg to obtain 313'
, 37.7 g of 4,4/-tetramethylpiphenyl were obtained. The yield was 90%.

Example 2 3.3', 4 ,4'-tetramethylbiphenyl was synthesized. The yield was 38.7 g, and the yield was 92 g.

Example 3 3.3', 4,4'- Tetramethylbiphenyl was synthesized. The yield was 34.9g, and the yield was S.
It was SS.

Example 4 111.3 g of potassium permanganate is dissolved in 3150 mt of water, and the solution is heated and stirred. After the temperature exceeds 90C, 20
3.3' to 46.5 g of potassium dihydroxide aqueous solution,
A slurry containing 33.6 g of 4,4'-tetramethylbiphenyl was divided into several portions, and unreacted tetramethylpiphenyl was extracted and recovered from the injection F solution using trichlorethylene. The separated aqueous solution was neutralized and crystallized using 4N hydrochloric acid, and the separated precipitates were dried to give 3.3', 4,4/-
51.9 g of biphenyltetracarboxylic acid dihydrate was obtained. The yield was 9 (EJ). The product melted at 295C with decomposition.

〔Effect of the invention〕

Claims (1)

[Claims] 1. Tetramethylbiphenyl is obtained by coupling a Grignard reagent represented by the following general formula ▲ Numerical formula, chemical formula, table, etc. ▼ (X represents a halogen) in the presence of copper chloride, A method for producing biphenyltetracarboxylic acid, which comprises subsequently oxidizing it in the presence of an oxidizing agent.