反应详情

20 parts of 2,5-bis-(m-chloroanilino)-dihydroterephthalic acid diethyl ester are oxidized by heating for three hours to 125° to 130° C. with 40 parts of m-chloronitrobenzene, with addition of 2 parts of glacial acetic acid and 0.6 part of piperidine. The 2,5-bis-(m-chloroanilino)-terephthalic acid diethyl ester is obtained having a content of chlorine of 14.7% (calculated: 15.0%).