Thermal isomerization of cyclobutenes. Part 11.—Perdeuteriocyclobutene

Abstract

The thermal isomerization of perdeuteriocyclobutene has been studied in the temperature range 140–180°C. The high-pressure rate constants for the Arrhenius equation k^∞_D= 10^{13.66 ± 0.16} exp (–33,760 ± 200/RT)sec^–1. The rate constant decreases with pressure below ∼20 mm. Rate constants for the isomerization have been measured down to 0.004 mm at 150.5°C. The “fall-off” curve obtained at this temperature has been compared with that obtained for cyclobutene and with various theoretical curves computed on the basis of the RRKM theory of unimolecular reactions.