Calorimetric study ofβ-cyclodextrin undecahydrate |
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Authors: | H Hanabata T Matsuo H Suga |
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Institution: | (1) Department of Chemistry and Chemical Thermodynamics Laboratory, Faculty of Science, Osaka University, 560 Toyonaka, Osaka, Japan |
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Abstract: | Heat capacities of crystalline-cyclodextrin undecahydrate have been measured in the temperature range between 13 and 300K by use of a miniaturized adiabatic low-temperature calorimeter. A first-order phase transition occurred at 226K with a discontinuous entropy change of 45.0 ± 1.0J
K
–1 mol–1. The highly disordered nature of the high temperature phase was considered in relation to the entropy contribution. A glass transition phenomenon observed around 150K was ascribed to the freezing of a configurational change of the protons engaged in the four-membered hydrogen-bonded ring which appeared only in the low temperature phase. |
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Keywords: | -Cyclodextrin undecahydrate" target="_blank">gif" alt="beta" align="MIDDLE" BORDER="0">-Cyclodextrin undecahydrate phase transition entropy of transition glass transition |
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