Pectate polyelectrolyte ionotropic gels: 1. Kinetics and mechanisms of formation of manganate (VI)–pectate intermediate complex during the oxidation of pectate polysaccharide by alkaline permanganate

The kinetics of formation of the [Pect MnVIO2−4] intermediate complex formed during the oxidation of pectate polysaccharide by permanganate ions in alkaline solutions at pH⩾12 have been measured by a conventional spectrophotometric technique. The reaction showed a first-order dependence on permanganate concentration and a fractional order with respect to the pectate concentration for the complex formation. Kinetic and spectrophotometric evidence revealed the formation of manganate (VI) transient species. The results obtained indicated that the rate of formation is base catalyzed. Thermodynamic parameters were evaluated and a suitable mechanism consistent with the kinetic results was suggested.