Abstract. The kinetics of Hg (II) co-catalysed and RuO4 catalysed oxidation of erythritol (Ery) and dulcitol (Dul) by potassium bromate in alkaline solution exhibit zero order in potassium bromate and first-order in both [RuO4] and [OH-]. First-order kinetics in low [substrates] tends to zero-order at their higher concentrations. Although mercuric acetate has been used as Br- ions scavenger but variation of its concentration shows positive effect on reaction rates. Addition of NaClO4 decreased the reaction rate, showing negative effect of ionic strength of the medium.  Mechanistic steps, supported by activation parameters and conforming to the observed kinetics, are discussed.

Graphical Abstract. Mechanistic steps based on kinetic studies of Hg (II) co-catalysed and RuO4 catalysed oxidation of erythritol and dulcitol by alkaline solution of potassium bromate have been reported and erythrionic acid and galactonic acid respectively have been detected as reaction products. The following rate law derived on the basis of reaction scheme conforms to all the kinetic observations, stoichiometry and reaction products.

                                  

                                      Where k = 2/3 kd k1 k2, a = k-1 k-2 and b = kd k2

KEY WORDS:  Oxidation, kinetics, KBrO₃, Ru(VIII)catalysis, erythritol, dulcitol.