Method for synthesizing 4,4'-diphenic acid

Abstract

The invention provides a method for synthesizing 4,4'-diphenic acid. In the method, high-boiling-point polyethylene glycol 400 is used as a solvent, cuprous iodide (CuI) is used as a catalyst, and 4,4'-diphenic acid is obtained in the condition of presence of diethylenediamine and potassium hydroxide (KOH) by a reduction coupling new method. The synthesis method has the advantages that the method for synthesizing 4,4'-diphenic acid is simple, the synthesizing condition requirements are not high, the operation is easy, the production cost is low, the yield is very high, the purity is also very high and the repeatability is good, so that the method is suitable for the requirements of large-scale industrialized production; the solvent polyethylene glycol 400 used by the reaction system has high steam pressure, does not pollute the environment and is environment-friendly; and the purification method is simple, column separation purification is not needed, and purification can be carried out just by a common recrystallization method.

Description

technical field [0001] The invention relates to a synthesis method, in particular to a method for synthesizing 4,4'-biphenyl dicarboxylic acid. Background technique [0002] 4,4'-biphenyldicarboxylic acid is an important organic synthesis intermediate, widely used in the synthesis of organic polymer materials, pharmaceuticals, coordination polymer supramolecular materials and liquid crystal products. At present, the synthesis of 4,4'-biphenyl dicarboxylic acid mainly contains the following routes: (1) 4,4'-dialkylbiphenyl is used as raw material and prepared by oxidation under high temperature and pressure. This method not only The raw material is expensive, and the reaction conditions are harsh, there are many by-products, separation and purification are difficult, and the yield is low (generally lower than 56%); (2) biphenyl is used as a raw material, and 4,4'-bis(chloromethyl) is produced through chloromethylation Methyl) biphenyl, and then undergo nucleophilic substitut...

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Problems solved by technology

At present, the synthesis of 4,4'-biphenyl dicarboxylic acid mainly contains the following routes: (1) 4,4'-dialkylbiphenyl is used as raw material and prepared by oxidation under high temperature and pressure. This method not only The raw material is expensive, and the reaction conditions are harsh, there are many by-products, separation and purification are difficult, and the yield is low (generally lower than 56%); (2) biphenyl is used as a raw material, and 4,4'-bis(chloromethyl) is produced through chloromethylation Methyl) biphenyl, and then undergo nucleophilic substitution reaction with hexamethylenetetramine to hydrolyze to 4,4'-biphenyldicarbaldehyde, and then oxidize with hydrogen peroxide to obtain 4,4'-biphenyldicarboxylic acid, which is synthesized by this method There are many steps, and the yield is only 38.2%; (3) taking p-carboxyphenylboronic acid and p-bromobenzoic acid as raw materials through Suzuki cross-coupling reaction, but the reaction conditions are high, and the raw materials must be esterified, and there are many reaction steps, and Uneconomical, also not suitable for suitability for suitability for industrialized production; (4) take p-iodobenzoic acid as raw material, through the coupling synthesis of zinc and triethylamine formate, the raw material price used is high, also uneconomical; (5) take p-aminobenzoic acid As a raw material, it is prepared by diazotization and then catalytic coupling of monovalent copper ions. The yield can reach 82%, but the diazotization conditions are high and not suitable for large-scale production

At present, the market price of 4,4'-biphenyl dicarboxylic acid is high, and it is necessary to develop a simple, economical and efficient new synthetic method to prepare 4,4'-biphenyl dicarboxylic acid, from raw materials, synthesis steps, reaction systems, etc. Reduce the production cost of 4,4′-biphenyldicarboxylic acid and meet the market demand

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