Thermal decomposition of hexamethylethane in a flow system

Hexamethylethane has been decomposed in a flow system in the temperature range of 700–900 K. The mechanism involves carbon–carbon bond cleavage at the most highly substituted position and rapid formation of isobutene from the t ‐butyl radical. The rate expression is\documentclass{article}\pagestyle{empty}\begin{document}$$ \begin{array}{*{20}c}{k({\rm (tC}_{\rm 4} {\rm H}_{\rm 9})_2 \to 2t{\rm C}_{\rm 4} {\rm H}_{\rm 9}.) = 10^{17.4} {\rm exp(} - 36,000/{\rm T)}} & {{\rm sec}^{ - 1}}\\\end{array} $$\end{document}and is completely consistent with deductions from radical buffer, shock‐tube, and direct recombination studies. Of special importance is experimental evidence for large decreases of the A factor with increasing temperature and a high heat of formation for the t ‐butyl radical, Δ H f ( t C 4 H 9 ·) 300 = 52.7 ± 6 kJ.