A comparative study on the production yield of H atom in the thermal decomposition of i-C₄H₁₀ and n-C₄H₁₀: Examination of the contribution of the roaming radical channels

The yields of H atoms in the thermal decomposition of i-C₄H₁₀ → products (1) and n-C₄H₁₀ → products (2) are measured at 1470–1800 K behind reflected shock waves. A comparative method is used to evaluate the branching fractions for i-C₄H₁₀ → CH₃ + i-C₃H₇ (1a) and n-C₄H₁₀ → 2C₂H₅ (2b), where, C₃H₆ is used as a reference. The branching fractions for (1a) and (2b) are expressed by k_1a/k₁ = (0.64 ± 0.14)(10⁻³T/K) − (0.06 ± 0.23) and, k_2b/k₂ = (0.050 ± 0.059)(10⁻³T/K) + (0.49 ± 0.10), respectively. Contributions of the roaming channels are less than 12 and 5% for i-C₄H₁₀ → CH₄ + C₃H₆ (1b) and n-C₄H₁₀ → CH₄ + C₃H₆ (2c), respectively.