Gas-phase thermolysis of sulfur compounds. Part VIII. Chloromethyl allyl, cyanomethyl allyl, 1-cyanoethyl allyl and neopentyl allyl sulfides

✍ Scribed by Gonzalo Martin; Henry Martinez; Harald Suhr; Ursula Suhr

• Publisher: John Wiley and Sons
• Year: 1986
• Tongue: English
• Weight: 341 KB
• Volume: 18
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/kin.550180308

✦ Synopsis

The pyrolyses of four alkyl allyl sulfides with substituents on the a-C atom of the alkyl moiety have been studied in a stirred-flow system over the temperature range 340-400°C and pressures between 2 and 12 torr. The only products formed are propene and thioaldehydes. The reactions showed first-order kinetics with the rate coefficients following the Arrhenius equations:

Chloromethyl allyl sulfide: k ( s -l ) = 101074ZO23 exp(-144 * 3) kJ/molRT Cyanomethyl allyl sulfide: k(s-l) = 101020~019 exp(-129 2 2) kJ/molRT 1-cyanoethyl allyl sulfide: k ( s -l ) = 101109l018 exp(-141.5 ? 2.2) kJ/molRT Neopentyl allyl sulfide: k(s-l) = 1010 5420 24 exp( -144 ? 3) kJ/molRT

The effects of these and other substituents on the reactivity is discussed in relation with the stabilization of a polar six-centered transition state. The results support a nonconcerted mechanism where the 1-5 a-H atom shift is assisted by its acidic character.