THE DECOMPOSITION KINETICS OF SODIUM PERBORATE CATALYZED BY ETHYLENEDIAMINETETRAKIS (METHYLENEPHOSPHONATO) IRON(III)

The catalysed decomposition of sodium perborate in the presence of diaminetetrakis(methylenephosphonato)-iron(III); (FeY)5-(Y is ENTMP) was studied at various temperatures and over the pH range 8.65-10.70. The observed rate law is given by : -d[BO3-]/dt=k1Ka[H+]+K2/1+K(a)[H+] [BO3-][FeENTMP]total where k1 and k2 are the specific rate constants for the normal and the ternary hydroxo complexes catalysed reaction. Activation enthalpies and activation entropies for the reactions were determined and found to be DELTAH-1# = 24.9 kJ/mol; DELTAH-2# = 32.2 kJ/mol and DELTAS1# = -185 J/K . mol; DELTAS2# = -155 J/K . mol.