Abstract: | Dilute mixtures of 4-methyl-l-pentyne have been pyrolyzed in a single-pulse shock tube. The decomposition process involves bond breaking: as well as a molecular reaction: The rate parameters are: The heat of formation of propynyl radical is thus ΔHf300 = 338 kJ mol?1 (80.7 kcal mol?1)˙ This leads to a propynyl resonance energy of 40 kJ mol?1 (9.6 kcal mol?1). |