Single-pulse shock tube studies of hydrocarbon pyrolysis. Part 5.—Pyrolysis of neopentane

Abstract

The thermal decomposition of neopentane has been studied in the single-pulse shock tube over the temperature range 1030–1300 K. The experimental results are fully explained by the generalized mechanism for alkane pyrolysis proposed by Bradley (Proc. Roy. Soc. A, 1974, 337, 199) provided the same special features are included i.e. “forbidden” radical isomerizations, hydrogen atom attack on olefins, and “high” rates for methyl radical abstraction reactions. Optimization by computer of the critical reaction parameters leads to the following rate constants neo-C₅H₁₂→ t–C₄H₉+ CH₃k₁= 3.3 × 10¹⁶ exp(– 336 kJ mol^–1/RT)S^–1(1), CH₃+ C₅H₁₂→ CH₄+ C₅H₁₁k₂= 6.6 × 10¹¹ exp(–90kJ mol^–1/RT) dm³ mol^–1 S^–1(2), H + C₄H₈→ C₄H₉k₁₄= 1.6 × 10¹⁰ exp(– 6.3 kJ mol^–1/RT) dm³ mol^–1 S^–1. (14)

The reaction behaviour is also sensitive to the reactions CH₃+ C₄H₈→ CH₄+ C₄H₇(19), C₄H₉→ CH₃H₆+ CH₃(6), C₄H₉→ C₂H₄+ C₂H₅(32), although absolute rate constants obtained for them cannot be regarded as reliable.