Abstract: A double extrapolation method was employed to determine the most probable mechanism for the thermal decomposition reaction of the survived β-cyclodextrin (β-CD) from the inclusion complex of β-CD with clove oil. The activation energy (Ea) curve calculated by Flynn-Wall-Ozawa method was clearly divided into three stages for the thermal decomposition process of the survived β-CD. The nearly parallel linear relationship between first and last stages was assessed as an Avrami-Erofe’ev A1.5 model. Furthermore, the platform in the second stage of the decomposition of the survived β-CD in which each point has approximately equivalent Ea was carefully investigated using the reaction order (n) method. A regular decline in n as the temperature increased implied a complicated decomposition reaction mechanism for the survived β-CD in this stage. Infrared spectroscopic profiles from the thermal decomposition of free β-CD and survived β-CD were also compared. The changes in IR spectra below 1000 cm-1 between free β-CD and survived β-CD in the decomposition process were quite different which agreed with the calculated Ea values.

Key words: β-Cyclodextrin, Inclusion complex, Double extrapolation, Thermal decomposition kinetics