A kinetic and mechanistic study on the thermal decomposition reactions of cis- and trans- fused 1,2,4-trioxanes

The kinetics of the thermal decomposition reactions of artemisinine (1), a cis-fused 1,2,4-trioxane, and trans-3,3dimethyl-1,2,4-trioxane (6) in solutions of benzene, toluene, and methanol in sealed tubes were compared at temperatures between 100.1° and 171.4 °C. Pseudo first-order rate constant val...

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Autores principales: Cafferata, Lázaro F. R., Jeandupeax, Rene, Romanelli, Gustavo Pablo, Mateo, Carmen Margarita, Jefford, Charles W.
Formato: Articulo
Lenguaje:Inglés
Publicado: 2003
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Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/98261
https://ri.conicet.gov.ar/11336/65056
https://dialnet.unirioja.es/servlet/articulo?codigo=2642748
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Sumario:The kinetics of the thermal decomposition reactions of artemisinine (1), a cis-fused 1,2,4-trioxane, and trans-3,3dimethyl-1,2,4-trioxane (6) in solutions of benzene, toluene, and methanol in sealed tubes were compared at temperatures between 100.1° and 171.4 °C. Pseudo first-order rate constant values were determined for conversions of both cyclic peroxides up to ca. 60%. The activation parameters and the composition of the reaction products were indicative of homolytic cleavage of their O-O bonds as the rate-determining steps followed by stepwise fragmentation. The free energies of activation (ΔG#) for 1 and 6 reactions in the aromatic solvents were calculated at the middle of each temperature range, giving values of 30.7 and 35.1 kcal/mol, respectively, which are evaluated considering their different molecular configurations. Furthermore, the rates of the thermal decomposition reactions of those trioxanes were sensitive to solvent effects.