KINETICS OF REACTIONS OF CHLORINE DIOXIDE (OCLO) IN WATER .1. RATE CONSTANTS FOR INORGANIC AND ORGANIC-COMPOUNDS

The kinetics of chlorine dioxide consumption by a wide range of inorganic and organic compounds, including a comprehensive series of phenols, have been determined using conventional batch-type and stopped-flow methods. In all cases, the rate law was first-order in chlorine dioxide and first-order in substrate. The methods allowed us to determine second-order rate constants over a range from 10(-5) to 10(5) M-1 s-1. Measured rate constants were high for nitrite, hydrogen peroxide, ozone, iodide, iron (11), and, whenever the pH was not very low, for phenolic compounds, tertiary amines, and thiols. Bromide, ammonia, structures containing olefinic C=C double bonds, aromatic hydrocarbons, primary and secondary amines, aldehydes, ketones and carbohydrates were unreactive under conditions of water treatment. For substrates that are weak acids, such as phenols, or weak bases, the effect of pH on the reaction rate showed that the rate constants for the deprotonated compounds are much higher than those for the protonated species.