Degradation and photodegradation of tetraacetylethylenediamine (TAED) in the presence of iron(III) in aqueous solution

The dark degradation of tetraacetylethylenediamine (TAED) was investigated, It is a slow process which is favored in acidic medium, There is a hydrolysis of an imide group with the scission of the C-N bond giving rise to the triacetyl derivative (TAED'). When allowed to stand for longer times a second acetyl group is eliminated with the formation of the symetric diacetyl derivative (DAED), The degradation of TAED photoinduced by iron(III) was also investigated, It appears a faster degradation which does not lead to the same products. The process only involves (OH)-O-. radicals formed upon photolysis of aquocomplex of iron(III). They preferentially abstract a hydrogen from the methylene group. The degradation is then assisted by oxygen and leads to the formation of carbonylated oxidation products. (C) 1997 Elsevier Science Ltd.