摘要：

Methylenecycloalkanes and 1-methylcycloalkenes have been equilibrated in acetic acid at 25° containing p-toluenesulfonic acid. The amounts of the isomers present at equilibrium and the approximate rates of equilibration were determined by gas chromatography. The equilibrium constants are: 1-methylcyclopentene/methylenecyclopentane 1144, 1-methylcyclohexene/methylenecyclohexane 240, 1-methylcycloheptene/methylenecycloheptane 74.4, and 1-methylcyclooctene/methylenecycloctane 598. Methylenecycloalkanes were found to be absent in the equilibrium mixtures of the nine- and ten-membered cyclic olefins. trans-1-Methylcyclodecene was formed initially almost as rapidly as the cis isomer in the isomerization of methylenecyclodecane, and subsequently decreased in amount to an equilibrium value of cis/trans 99.5/0.5. A possible explanation of this phenomenon is discussed.

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