Peracetic acid (Pa) is now being used for totally chlorine-free delign
ification and bleaching of wood pulps. During the process, metals deso
rb from the pulp fibers into the aqueous solution. Of the relevant met
als in bleaching systems, cobalt(II) and vanadium(V) are the most pote
nt in wastefully decomposing Pa to O-2 In the present study, radical s
cavenging by N,N-(5-nitro-1,3-phenylene)-bisglutaramide (GAMID) indica
tes that free-radical mechanisms are operative. Kinetic data support a
free-radical decomposition mechanism previously described for Co(II).
A similar type of mechanism, involving VO(ON)(2(aq)) and VO(OH)(3(aq)
), is postulated to partially explain catalysis by vanadium.