Ia. Salem et al., KINETICS AND MECHANISM OF THE DECOMPOSITION OF HYDROGEN-PEROXIDE CATALYZED BY MN(II)-BIS-SALICYLALDIMINE COMPLEXES, Monatshefte fuer Chemie, 126(4), 1995, pp. 393-399
The tetradentate Schiff bases N,N'-bis(salicylidene) ethylenediamine (
salen), N,N-bis-(salicylidene) hexylenediamine (salhex), and N,N'-bis(
salicylidene)-o-phenylenediamine (sal-o-phen) are very strongly adsorb
ed by cation exchange resins (Dowex-50W) with manganese(II) as a count
er ion, forming stable complexes. The kinetics of the catalytic decomp
osition of H2O2 in presence of these complexes has been studied in aqu
eous medium. The decomposition reaction is first order with respect to
H2O2 in the case of salen and sal-o-phen and third order in the case
of salhex. The greater the ligand methylene chain length or the greate
r the steric effect of the ligand, the greater will be the rate of rea
ction. The reaction is governed by the entropy of activation. A reacti
on mechanism is proposed.