2,5-联苯二甲酸合成的新方法

New Synthesis Method of 2,5-Biphenyldicarboxylic Acid

2,5-联苯二甲酸是高分子合成单体,它的合成对于高强度纤维制品及高分子液晶理论的研究具有重要意义.在室温下,对二甲苯与溴在铁粉催化下进行反应,制成2-溴对二甲苯,并将其制成相应的有机铜试剂,与溴苯在NiCl2(PPh3)2催化下进行交叉偶联,得到2,5-二甲基联苯,再用KMnO4水溶液氧化,合成2,5-联苯二甲酸,产率达到65%左右.其结构由IR确认.

2,5-Biphenyldicarboxylic acid is a monomer of pulymer, its synthesis has importance for high strength fiber and theoretical research in sub-LCD in polymer. The p-xylene reacts with Br2 in the presence of Fe filing at room temperature to get 2-bromo-p-xylene. The 2-bromo-p-xylene is converted to Cu reagent, which reacts with bromobenzene in the presence of NiC12（PPh3 ）2, a selective cross-coupling catalyst,2,5-dimethyl-biphenyl is synthesized, Then 2,5-dimethyl-biphenyl is oxidated with KMnO4 to give the title compound.＇ The yield can attain 65 % or so. The structure of product is identified by IR.