Isomerization of cycloheptane, cyclooctane, and cyclodecane catalyzed by sulfated zirconia-comparison with open-chain alkanes
Satoh, D; Matsuhashi, H; Nakamura, H; Arata, K
The skeletal isomerization of cycloalkanes with the number
of carbons greater than six, cycloheptane, cyclooctane, cyclodecane. and cyclododecane, was
performed over sulfated zirconia in liquid phase at 50degreesC. A main product of
methylcyclohexane was formed from cycloheptane via a protonated cyclopropane intermediate,
protonated [4.1.0]bicycloheptane, together with small amounts of trans-1,2-dimethylcyclopentane,
cis- and trans-1.3-dimethylcyclopentanes, 1,1-dimethyleyclopentane, and ethylcyclopentane. A
major product from cyclooctane was ethylcyclohexane via a protonated cyclobutane intermediate,
protonated [4.2.0]bicyclooctane, followed by cis-1,3-dimethylcyclohexane in addition to small
amounts of trans-1,2-, -1,3-, -1,4-dimethylcyclohexanes, 1,1-dimethylcyclohexane, and
methylcycloheptane. The detailed reaction-paths for cycloheptane and cyclooctane were shown after
additional examinations in reactions of methylcyclohexane, ethylcyclopentane, ethylcyclohexane,
and 1,2-dimethylcyclohexane. Cyclodecane was dehydrogenated into cis- or trans-decaline with the
evolution of a dihydrogen. Cyclododecane was converted into lots of products. more than 30
species.