Improvements in the Method for Preparing bis- (4′-n-Alkoxybenzal)-2-Chloro-1,4-Phenylenediamines

Abstract

Abstract An improved synthetic procedure for the preparation of bis-(4′-n-alkoxybenzal)-2-chloro-1,4-phenylenediamines has been developed. A detailed procedure for the isolation of the starting diamine. 2-chloro-1,4-phenylenediamine, from its sulfate salt and its purification is presented. Condensation of this diamine with the 4-alkoxybenzaldehydes in the presence of a catalytic amount of acetic acid and refluxing in ethanol for 18 hours gave high yields of the desired dianils. A shorter reflux time of 5 hours gave a mixture of the dianil 5 and monoanil 3. The use of molecular sieves in place of the acetic acid yielded primarily the monoanil.