THERMAL-DECOMPOSITION OF THIIRANE AND 2-METHYLTHIIRANE - AN EXPERIMENTAL AND THEORETICAL-STUDY

The thermal decomposition of thiirane and 2-methylthiirane was investi gated in a flow system by following the changes in their photoelectron spectra at various temperatures. Similar decomposition patterns were observed in both cases. Thus at 600 degrees C. formation of sulfur and an alkene was detected. At higher temperatures, conversion of thiiran e into ethenethiol and thioacetaldehyde, and of 2-methylthiirane into cis- and trans-prop-1-ene-1-thiol was observed. Hydrogen sulfide, alky nes, carbon disulfide and thiophene were detected as products of secon dary reactions. The experimental data pertaining to the rearrangement processes are compared with potential energy profiles. calculated by u sing the MNDO/CHAIN procedure. A mechanism involving initial C-S bond breaking, followed by 1,2-hydrogen shift, is suggested by the results.