Reaction of t-butyl radicals with hydrogen and with oxygen

Abstract

t-C₄H₉ radicals have been produced by the decomposition of 2,2,3,3-tetramethylbutane in the presence of H₂ and of O₂ in KCl-coated reaction vessels. From the measurement of the relative yields of i-C₄H₈ and i-C₄H₁₀ in the early stages of reaction over the temperature range 440–540°C, values of E₁₀–E₂= 61.9 ± 2.0 kJ mol^–1 and A₂/A₁₀= 0.35 ± 0.10 have been obtained.

t-C₄H₉+O₂= i-C₄H₈+HO₂(2),tC₄H₉+H₂= i-C₄H₁₀+H(10)

By use of the accurately known value of k_-10 and of thermochemical data for reaction (10), absolute values of k₂ and k₁₀ have been calculated and compared with rate constants for analogous reactions. Recommended values of Δ_fH°(t-C₄H₉)= 16.1 ± 4 kJ mol^–1 at 480°C and D^°₂₉₈(t-C₄H₉H)= 392.7 ± 4 kJ mol^–1 are given. Arrhenius parameters are suggested for reactions (2) and (10).