Shock tube pyrolyses. Part II. Thermal decompositions of isopropyl, n-butyl, isobutyl and t-butyl fluorides

Abstract

The dehydrofluorinations of isopropyl, n-butyl, isobutyl, and t-butyl fluorides have been studied by use of a comparative shock tube technique. The rate constants for these reactions are given by: log k/s^–1= 13·36 ± 0·32 –(53,900 ± 1000/2·3RT) for isopropyl fluoride; 13·28 ± 0·54 –(56,800 ± 2000/2·3RT) for n-butyl fluoride; 13·31 ± 0·65 –(58,600 ± 2500/2·3RT) for isobutyl fluoride; and 13·42 ± 0·34 –(51,500 ± 1200/2·3RT) for t-butyl fluoride. The results are consistent with an ionic transition state in which the rate-controlling step is the initial polarisation of the carbon–halogen bond.