10034-12-5Relevant articles and documents
Kinetics of the Gas-phase Thermal Decompositions of 1-Methoxy-1-methylcyclopropane and cis- and trans-1-Methoxy-2-methylcyclopropane
Awan, Iftikhar A.,Flowers, Michael C.
, p. 1415 - 1424 (2007/10/02)
In the temperature range 665-737 K the thermal decomposition of 1-methoxy-1-methylcyclopropane follows first-order kinetics with a rate constant given by the equation k/s-1 = 1014.76 +/- 0.81 exp(-252 +/- 10 kJ mol-1/RT).The presence of the 1-methyl substituent destablises the transition state for reaction.Secondary decomposition of the initially formed isomeric products precludes the determination of their individual rates of formation.Cis- and trans-1-methoxy-2-methylcyclopropane undergo first-order, reversible, geometric isomerisation in competition with structural isomerisation to give cis- and trans-1-methoxybut-1-ene and 1-methoxy-2-methylpropene in the temperature range 597-689 K: kcis -> trans/s-1 = 1015.25 +/- 0.23 exp(-235.4 +/- 2.8 kJ mol-1/RT), ktrans -> cis/s-1 = 1014.99 +/- 0.80 exp(-233.7 +/- 9.9 kJ mol-1/RT), kcis -> cis-1-methoxybut-1-ene/s-1 = 1013.79 +/- 0.29 exp(-233.1 +/- 3.6 kJ mol-1/RT), kcis -> trans-1-methoxybut-1-ene/s-1 = 1013.29 +/- 0.66 exp(-234.4 +/- 8.1 kJ mol-1/RT), kcis -> 1-methoxy-2-methylpropene/s-1 = 1012.4 +/- 1.0 exp(-225 +/- 12 kJ mol-1/RT), ktrans -> cis-1-methoxybut-1-ene/s-1 = 1014.05 +/- 0.62 exp(-243.7 +/- 7.8 kJ mol-1/RT), ktrans -> trans-1-methoxybut-1-ene/s-1 = 1013.0 +/- 0.9 exp(-233 +/- 11kJ mol-1/RT), ktrans -> 1-methoxy-2-methylpropane/s-1 = 1013.5 +/- 1.0 exp(-235 +/- 13 kJ mol-1/RT).On the basis of a biradical mechanism the results provide evidence for the formation of distinguishable biradicals on opening the cis- and trans-1-methoxy-2-methylcyclopropane ring.Estimates are made of the relative rates of ring closing, internal rotation and hydrogen-atom transfer of the biradicals.
