In this report the relation between the structure and the detergency performance of the chelate-forming dicarboxylates containing nitrogen or sulphur atom was discussed. Then disodium salts of azadiacetic, azadipropionic, thiodiglycolic, thiodipropionic, hydrazinodiacetic, hydrazinodipropionic, 2-hydroxyethyliminodiacetic and 2-hydroxyethyliminodipropionic acids were prepared and their building performances were compared with disodium oxadiacetate and sodium tripolyphosphate (STPP) using alkylbenzene sulf ovate.
The detergency tests were carried out on naturally soiled cotton fabrics and the detergency powers were evaluated by Scheffe's method.
From the results summarized in Table-1, it is evident that disodium salt of 2-hydroxyethylimi-nodiacetic acid with alkylbenzenesulf ovate is as well active as STPP. In the case of dibasic acids containing imino or thioether group, diacetates are more active than di-β-propionates as in the case of oxadicarboxylates. These orders of activities are generally paralleld with those of stabilities of the chelates. The detersive effect of the dicarboxylates decreases as in the following order; oxadicarboxylate>azadicarboxylate>thiodicarboxylate. This tendency also agreed with that of the stability constants with divalent calcium chelates.