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Saturday, July 19, 2014
Abstract-Kinetics of Polymorphic Transitions of Cyclohexanol Investigated by Terahertz Absorption Spectroscopy
The phase behaviors and kinetics of the polymorphic transitions of cyclohexanol, C6H11OH, were investigated by terahertz absorption spectroscopy over the temperature range of 150–330 K. A new phase was found, labeled phase I′, which is more stable than the previously observed phase I but less stable than phase III′. The kinetics of the irreversible transitions from phase I to I′, phase I to III′, and phase III′ to III were analyzed using Avrami’s theory. The transition geometries of the first two transitions were found to be one-dimensional, while the latter was two-dimensional. The transitions from phase I to III and phase III to II were revealed to occur through two-step processes. The mechanism of these irreversible transitions is discussed in relation to the formation and dissociation of hydrogen bonds between the hydroxyl groups as well as the steric restriction effects of the cyclohexyl ring.