Competitive alkali-metal flame reactions. Part 5. Reactions of potassium atoms with fluorobenzene, fluoroanisoles, and t-butyl chloride and of potassium and caesium atoms with p-alkylchlorobenzenes

Abstract

The kinetics of the abstraction of fluorine atom from fluorobenzene and fluoroanisoles by potassium atom and of chlorine atom from p-alkylchlorobenzenes by potassium and caesium atoms have been studied in the gas phase by a competitive method using t-butyl chloride and ethyl iodide as standards, respectively, in a modified diffusion flame reaction system. The results show that (a) the trend in the reactivities of fluorobenzene and fluoroanisoles follows the sequence o > m > p > u, where o, m, p, and u mean ortho-, meta-, and para-substituted and unsubstituted fluorobenzene, respectively; (b) the sequence in the reactivities of p-alkylchlorobenzenes towards potassium and caesium atoms is p-t-butylchlorobenzene > p-chlorocumene > p-ethylchlorobenzene > p-chlorotoluene > chlorobenzene; and (c) the rate of abstraction of chlorine atom by caesium atom is faster than that by potassium atom.