OXIDATION OF FORMALDEHYDE BY CHLORITE IN BASIC AND SLIGHTLY ACIDIC MEDIA

The reaction of chlorite and formaldehyde was studied in basic and sli ghtly acidic media. Though the expected product was CO2, the oxidation of HCHO, however, gave nearly quantitative formation of ClO2, the oxi dation product of ClO2-. In excess HCHO the stoichiometry of the react ion was deduced as 3ClO(2)(-) + HCHO + 2H(+) --> HCOOH + 2ClO(2)(aq) Cl- + 2H(2)O; but in high excess of ClO2- the stoichiometry was 6ClO( 2)(-) + HCHO + 4H(+) --> CO2(g) + 4ClO(2)(aq) + 3H(2)O + 2Cl(-). The r eaction is autocatalytic in HOCl. The first step of the reaction produ ces HOCl, which catalyzes the formation of ClO2 and further oxidation of HCOOH to CO2. ClO2 was found to be relatively unreactive toward HCH O and HCOOH, and hence it accumulated rapidly.