Shock Tube Studies of Sulfur Tetrafluoride Dissociation

Abstract

Shock tube studies of SF4 dissociation have been made in the temperature range 1650–1950°K. Rate constants for the initial fragmentation of SF4 have been determined from ir measurements and are explainable in terms of classical unimolecular reaction kinetics. The data were correlated with the Rice–Ramsperger–Kassel (RRK) theory; the values used were 79.0 kcal/mole for the SF3–F bond strength, 1013.63 sec−1 for the pre-exponential A factor, λDσm2 = 5.79 × 10−16cm2, and S = 6. Kinetic rates obtained from exponentially decaying radiation at 12.6 μ and temperatures of 2050–2800°K are attributed to SF3 and lie near the low-pressure limit of unimolecular reactions. The SF3 dissociation rates can be described by k = 4.29 × 1015exp(− 71.8 / RT) cc/mole·sec, where R is in kilocalories per mole·degree Kelvin.