Potential bleach activators with improved imide hydrolytic stability

Abstract

The commercially available bleach activator, N,N,N′,N′-tetraacetylethylenediamine (TAED), has been widely used in laundry detergents to enable efficient low-temperature bleaching. However, the competitive hydrolysis of TAED limits its use in liquid detergents. Herein we report the synthesis of two TAED derivatives, N,N,N′,N′-tetracetylpropylene-1,2-diamine (TA(Me)ED) and N,N,N′-triacetylpropylene-1,2-diamine (TriA(Me)ED), through the acetylation of propylene-1,2-diamine. The hydrolytic and perhydrolytic activity of the imide molecules were studied by HPLC to elucidate the structure–function relationship. Due to the increased steric hindrance imparted by the α-methyl group close to the imide, TA(Me)ED and TriA(Me)ED exhibited higher hydrolytic stability than TAED, with the hydrolytic rate constants (kH) at pH 8.0 decreased by 58% and 84% for TA(Me)ED and TriA(Me)ED, respectively. On the other hand, TA(Me)ED and TriA(Me)ED showed comparable perhydrolytic activity with TAED in the presence of peroxide, enabling similar bleaching effect of a model food dye at room temperature. These results suggest these TAED derivatives may have potential being used as improved bleach activators.