Re: The mechanism for the decomposition of H2O2 with iron(III) as the catalyst?

First,I need to make two assumptions. From the description of the ferric iron solution it is ferric chloride. The counter anion to the cationic ferric species can play an important role in complexation. Secondly since the ferric iron is in solution, I am assuming that the pH is less than 2.0. The most likely reaction sequence (given the above assumptions) involves no complexing lignands except for water. The complete suite of reactions are: Fe(3+) + H2O2 = Fe-OOH(2+)(The brown product) + H(+) Fe-OOH(2+) = HO2(hydroperoxyl radical) + Fe(2+) Fe(2+) + HO2(hydroperoxyl radical) = Fe(3+) + HO2(-) Fe(3+) + HO2(hydroperoxyl radical) = Fe(2+) + O2 + H(+) additional reactions stimulated by the presence of the ferrous ion include: Fe(2+) + H2O2 = Fe(3+) + OH(hydroxyl radical) + OH(-) (the Fenton's Reaction) OH(hydroxyl radical) + Fe(2+) = HO(-) + Fe(3+) OH(hydroxyl radical) + H2O2 = H2O + HO2(hydroperoxyl radical) (3+), (2+), and (-) are charges and should be superscripts If my above assumptions are not correct. Let me know what the solution conditions are and I will revisit the question. Dave Vance