Gas-phase thermal unimolecular decomposition of oxetan

Abstract

The gas phase pyrolysis of oxetan has been re-investigated at temperatures from 693 to 753 K and at initial pressures from 53.3 to 15 598 N m^–2(0.40 to 117.0 Torr). At high pressures the pyrolysis to give ethylene and formaldehyde is a homogeneous unimolecular process with a rate-constant given by log₁₀(k_∞/s^–1)=(15.71 ± 0.31)–(263 696 ± 3510)J mol^–1/2.303RT.

Unimolecular fall-off has been observed at two temperatures, and the half-pressure is approximately 133.3 N m^–2(1 Torr) at 737.5 K. Calculations based on the RRKM treatment and also on the Forst method give fall-off curves in good agreement with experiment at the half-pressure.