GAS-PHASE THERMOLYSIS OF SULFUR COMPOUNDS. PART VII. 4,6-DITHIA-1-OCTENE, 4,6-DITHIA-1,8-NONADIENE AND 4,6-DITHIA-6-PHENYL-1-HEXENE

Abstract

Under stirred-flow conditions, the title compounds pyrolyze to yield propene and the ethyl, allyl and benzyl dithioformates, respectively, as reaction products.

The first order rate coefficients of these unimolecular decompositions followed the Arrhenius equations

4,6-dithia-1-octene k (sec⁻¹)=10^{10.85 ± 0.18}exp (-142 ± 2 kJ/mol RT)

4,6-dithia-1,8-nonadiene k (sec⁻¹)=10^{10.45 ± 034}exp (-132 ± 4 kJ/mol RT)

4,6-dithia-6-phenyl-1-hexene k (sec⁻¹)=10^{10.09 ± 043}exp (-130 ± 5 kJ/mol RT)

The activation parameters are discussed in relation to those of other allyl sulfides. These suggest that a sulfur atom can stabilize the transition state to the same extent as a π-electron system.