Observations on shock induced chemistry of cyclohexane

We use double pass absorption spectroscopy to examine shock induced reactions in situ in cyclohexane and benzene at pressures up to 33.1 GPa. Reactions in cyclohexane begin by 27 GPa and complete by 33.1 GPa. Reactions in benzene are observed to begin by 12 GPa and are complete by 18 GPa. Absorption spectra indicate that the first reaction in cyclohexane occurs within or near the shock front, and that a metastable local equilibrium is reached in the post-shock state. A second process may be observed upon reshock at the lower pressures, suggesting a new equilibrium is reached post-reshock as well. Absorption bands are consistent with the formation of short radicals or fragments upon decomposition; however, spectral resolution is too low to confirm this mechanism.