Synthetic method of biphenyl-4-formic acid

Abstract

The invention relates to the field of chemical synthesis, in particular to a synthetic method of biphenyl-4-formic acid. The method is characterized by comprising the following reaction steps: 1) a mole ratio of biphenyl, oxalyl chloride and anhydrous aluminium trichloride is 1:(0.5-1.1):(1.0-1.6); a weight ratio of biphenyl to a solvent is 1:(3-10); after reaction, a reactant is added to ice water, and layered; biphenyl benzil is obtained; and 2) a mole ratio of biphenyl benzil, an oxidant and potassium hydroxide is 1:(1.2-2.0):(1.4-2.2); a weight ratio of biphenyl benzil to an organic solvent is 1:(3-10); after reaction, a reaction liquid is adjusted to be acid by a 10% HCL solution; recrystallization is performed by absolute methanol; and biphenyl-4-formic acid is obtained. Compared with the prior art, the method has the benefits that the method is reasonable in technological process, mild in technological reaction condition, and low in equipment requirement, and is suitable for industrial production, and a yield reaches above 91%.

Description

technical field [0001] The invention relates to the field of chemical synthesis, in particular to a synthesis method of biphenyl-4-carboxylic acid. Background technique [0002] Biphenyl-4-carboxylic acid is the main 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 biphenyl-4-carboxylic acid mainly has the following routes: (1) use 4-alkylbiphenyl as raw material and prepare it by oxidation under high temperature and pressure. Harsh, many by-products, difficult separation and purification, low yield (generally less than 56%); (2) biphenyl is used as raw material, chloromethylated to generate 4-chloromethyl biphenyl, and then combined with hexamethylene tetra The amine is hydrolyzed into biphenyl-4-carbaldehyde by nucleophilic substitution reaction, and then oxidized with hydrogen peroxide to obtain biphenyl-4-carb...

AI Technical Summary

Problems solved by technology

At present, the synthesis of biphenyl-4-carboxylic acid mainly has the following routes: (1) use 4-alkylbiphenyl as raw material and prepare it by oxidation under high temperature and pressure. Harsh, many by-products, difficult separation and purification, low yield (generally less than 56%); (2) biphenyl is used as raw material, chloromethylated to generate 4-chloromethyl biphenyl, and then combined with hexamethylene tetra The amine is hydrolyzed into biphenyl-4-carbaldehyde by nucleophilic substitution reaction, and then oxidized with hydrogen peroxide to obtain biphenyl-4-carboxylic acid. This method has many synthetic steps, and the yield is only 38.2%. Bromobenzoic acid is a raw material through Suzuki cross-coupling reaction, but the reaction conditions are high, and the raw material must be esterified, and the reaction steps are many, which is not economical and is not suitable for industrial production; (4) using p-iodobenzoic acid as a raw material, through Coupling synthesis of zinc and triethylamine formate, the price of raw materials used is high, and it is also uneconomical; (5) using p-aminobenzoic acid as raw material, first diazotized and then prepared by catalytic coupling of monovalent copper ions, the yield It is relatively high, but the diazotization conditions are high, and it is not suitable for large-scale production; (6) Biphenyl-4-carboxylic acid is prepared by using biphenyl as a raw material and reacting with carbon dioxide under high pressure. The yield is 91%, but the equipment is demanding. Not suitable for industrial production