Pyrolyses of some highly branched secondary acetates

Abstract

Three highly branched secondary acetates were pyrolysed in a static system over the pressure range 25–300 mmHg and the temperature range 305–380 °C. The reactions in seasoned vessels were found to be homogeneous and unimolecular. The temperature-dependence of the rate constants is given by the Arrhenius equations: 3-acetoxy-2,2-dimethylbutane, log k₁/s^–1= 12·5 ± 0·22 –(44,060 ± 600 cal mol^–1)/2·303RT; 3-acetoxy-2,2-dimethylpentane, log k₁/s^–1= 13·06 ± 0·09 –(44,850 ± 780 cal mol^–1)/2·303RT; and 3-acetoxy-2,2,4-trimethylpentane, log k₁/s^–1= 13·12 ± 0·08 –(46,600 ± 230 cal mol^–1)/2·303RT. Variation of the rate of reaction within the series is interpreted in terms of structural and electronic factors.