STRUCTURES, THERMAL STABILITIES AND KINETICS OF DESOLVATION OF DIOL INCLUSION COMPOUNDS
Hong Su, A. Coetzee, L. R. Nassimbeni
Department of Chemistry, University of Cape Town, Rondecosch 7701, South Africa
Keywords:
Inclusion Compound, Selective Inclusion, Thermal Kinetics
Separation of close isomers by enclathration is one of the important uses of inclusion chemistry and has considerable future industrial prospect. The principle of separation by enclathration is based on molecular recognition, a subject which has been extensively reviewed1. It is generally accepted that the molecular recognition during crystallisation depends on the complementarity of molecular features. The process of crystallisation is also subject to both kinetic and thermodynamic factors. Therefore the recognition or selectivity of a host for different guests may be evaluated through the studies of physical properties, molecular structures, thermal stabilities and kinetics.
The inclusion compounds, between the host, trans-9,10-dihydroxy-9,10-diphenyl-9,10-dihydroanthracene (H), and four related guests, cyclohexanone and the three methyl-substituted cyclohexanones have been studied. The crystal structures were elucidated by X-ray diffraction method. The thermal stabilities of inclusion compounds were evaluated by thermogravimetry (TG), differential scanning calorimetry (DSC) and hotstage microscopy (HSM). The isothermal kinetics were investigated by measuring mass loss versus time during the reaction2. The selectivity of the host to the four targeted guests were studied by conducting two or three components competition recrystallisation, in an attempt to find reasonable trends in terms of measured physico-chemical quantities.