This article describes the structural stabilities of 5,10,15,20-tetrakis(2.6-dichloro-3-sulfonatophenyl)porphinatomanganese(III) X (X: OH-. H2O) (MnTDCSPP), 5,10,15,20-tetra(4-sulfonatophenyl)porphinatomanganese(III) X (X: OH-, H2O) (MnTSPP) and their supported analogues toward H2O2 and NaOCl or HOCl depending on pH. The supports employed were hexadecyltrimethylammonium bromide (CTAB), 2,6-ionene, 2,10-ionene and a poly(vinylbenzyltrimethylammonium chloride) latex, which all contain quaternary ammonium groups. In the strong basic medium, both manganese porphyrins showed high stabilities toward NaOCl but relatively lower stabilities toward H2O2, and the resistance of MnTDCSPP to degradation was higher than that of MnTSPP. In the acidic solution, both porphyrins showed increasing stabilities toward H2O2 as the pH went down. Toward HOCl, MnTSPP did not show any stability in the neutral and acidic solutions, whereas MnTDCSPP showed some. The supports made some influence on their stabilities. In general, the ionenes affected their stabilities adversely, and the latex and CTAB did positively. Especially when they were bound to CTAB, they were not degraded by H2O2 at pH < 2. The pseudo-First-order degradation rate constants of MnTDCSPP, MnTSPP, and their supported analogues at different pHs at 30 degrees C were determined. (C) 2000 John Wiley & Sons, Inc. Int J Chem Kinet 32: 271-278, 2000.