Synthesis of model diamide, diester and esteramide adducts and studies on their chlorine tolerance

The stability of various aromatic adducts containing diamide, diester and esteramide linkages towards chlorine gives an insight into the development of improved polymer structures which may be useful as reverse osmosis membranes. Model aromatic compounds were prepared by benzoylation of various diamines (o-, m- and p-phenylene diamines), diols(hydroquinone, resorcinol and bisphenol-A) and m- and p-aminophenols. These adducts were subjected to chlorine treatments of increasing severity and their susceptibility to attack was monitored by melting point and NMR measurements. The diesters showed the highest chlorine resistance while the esteramides showed similar susceptibility as the diamides. The chlorine resistance of the diamides and esteramides was strongly influenced by the substitution (o-, m-, p-) pattern, with the o-phenylene diaminebased adduct showing as high chlorine resistance as the diesters.