Shock-Tube Studies of Sulfur Hexafluoride

Abstract

Shock‐tube kinetic studies of SF₆ dissociation in argon have been made in the temperature range of 1650°–2050°K at pressures from 0.13–30 atm. Rate constants for the initial fragmentation of SF₆ have been determined and have been found to be explainable in terms of classical unimolecular reaction kinetics. The analysis of the data in terms of the RRK theory yielded $\text{S\hspace{0.17em}=\hspace{0.17em}6}$ , ${\lambda }_D\text{\hspace{0.17em}=\hspace{0.17em}0.25}$ , $E_0\text{\hspace{0.17em}=\hspace{0.17em}75.92}\mathrm{kcal}/\mathrm{mole}$ , and ${\text{A\hspace{0.17em}=\hspace{0.17em}10}}^{\text{12.95}}{\sec }^{\text{−1}}$ as the best values of the unimolecular parameters. The data did not rule out values of 5 to 7 for $S$ or a factor of 2 range in ${\lambda }_D$ with corresponding variations of about 4 kcal/mole in $E_0$ and a factor of 3 in $A$ . $E_0\text{\hspace{0.17em}=\hspace{0.17em}75.92}\mathrm{kcal}/\mathrm{mole}$ represents the strength of the first S–F bond. Both ir and uv techniques were used to obtain the data.