The azoethane‐sensitized thermal reaction of isobutene has been studied at 526–565 K. The initial concentrations of azoethane and isobutene were in the ranges of 1.40–10.5 × 10−4 and 6.78–26.6 × 10−4 mol/dm3, respectively. From the initial rates of formation of ethane and 2‐methylpentane the heat of formation of the 2‐methyl‐2‐pentyl radical was determined. The result obtained is ±H f0(2‐methyl‐2‐pentyl) = 0.8 ± 2.0 kcal/mol. The entropy of the radical, obtained from statistical mechanical calculations and experimentally, is S0(2‐methyl‐2 pentyl) = 92.8 ± 1.5 cal/mol°K. The results support the high heat of formation of the t‐butyl radical suggested by different authors.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Organic Chemistry
- Inorganic Chemistry