The authors synthesized two series of dibasic acids containing ether linkages, oxadiacetic acids and oxadipropionic acids, which were respectively obtained from polyethylene glycols by the air oxidation and from water or formaldehyde or ethylene glycol by the cyanoethylation and subsequent hydrolysis. Disodium salts of dibasic acids were prepared and compared to the sodium tripolyphosphate (STPP) and sodium citrate with their detergency building action.
The detergency tests were carried out on naturally soiled cotton fabrics and the comparison was made by Scheffe's method. The builders employed were sodium tripolyphosphate (STPP) or disodiumsalts of dibasic acids, or sodium citrate, or the mixture of STPP and disodiumsalts of dibasic acids, or the mixture of STPP and sodium citrate.
As a result, the oxadiacetic acid series achieved better building performance than oxadipropionic acid series, and in each series, the smaller molecular weight of the test builder showed the better building power. The reason of these results can be explained that oxadiacetic acid formed a five membered ring with calcium, while oxadipropionic acid probably formed a six membered ring and stability difference between the two chelate ring systems caused the difference of their building actions. Another reason is the difference of the molecular weight. This is interpreted as the “Chelating value” or C.V.. To chelate a given amount of metal it requires less quantity of the minor molecular weight builder than that of the higher.
