Exchange reaction between chlorine gas and potassium chloride crystal

Abstract

Isotopic exchange reactions between chlorine gas and potassium chloride crystals were studied at –25 to ∼220°C in a carefully dehydrated vacuum system. The reaction in the first layer of the crystal obeys first-order kinetics, and the first layer consists of two kinds of domains with different reactivities with activation energies of 2.9 and 6.0 kcal/mole, respectively. The kinetics for the second, the third and the fourth layers is well described by successive first-order equations. The activation energy becomes progressively higher, from 10 to 40 kcal/mole, as the reaction proceeds from the second to the fourth layer, and approaches 42 kcal/mole, the value of self-diffusion of chloride ions in the bulk phase.