OXIDIZED GLUCOSIDIC OLIGOMERS - A NEW CLASS OF SEQUESTERING AGENTS - PREPARATION AND PROPERTIES

Oxidized polyglucosides obtained from starch, cellulose or dextrins ha ve very interesting properties as calcium sequestrants and are potenti ally useful as tripolyphosphate substitutes in detergent formulations. Unfortunately, they are poorly biodegradable. On the other hand, oxid ized polyglucosides of lower molecular weight, easily obtainable from starch or dextrins via enzymatic hydrolysis and successive oxidation w ith sodium hypochlorite are biodegradable and retain sequestering prop erties. In the present work, we compare first of all the sequestering properties and biodegradability of oxidized starch, dextrins, glucosid ic oligomers and maltotriose. Oxidation has been achieved in all cases with sodium hypochlorite. However, well-defined molecular structures have also been prepared by oxidation of starch and dextrins in two ste ps with sodium periodate and sodium chlorite, respectively. The produc ts obtained have been compared with the corresponding ones obtained by oxidation with sodium hypochlorite and gave similar results. In fact, sodium hypochlorite oxidizes hydroxyls mainly on the carbon atoms in position 2 and 3 of the glucosidic units, even if with much less selec tivity than periodate + chlorite. The reactivity properties of the org anic substrates with sodium hypochlorite are in the order maltotriose/ dextrins/starch with a ratio of 20/3/1.