STRUCTURE AND DECOMPOSITION KINETICS OF INCLUSION COMPOUNDS OF A DIOL HOST. Susan A. Bourne, Chemistry Department, University of Cape Town, Rondebosch 7700, South Africa

Inclusion chemistry offers wide scope for carrying out selective separation reactions. Considerable effort has gone into trying to improve the applications offered by naturally occurring resolving agents such as tartaric acid or brucine. An example is the class of compounds derived from a tartaric acid, such as (1) or (2).

The crystal structures of (1) (4,5-bis(hydroxydiphenylmethyl-2,2-dimethyl-1,3-dioxolane) with methanol and ethanol have been elucidated. These two compounds are isostructural, with the alcohol trapped in a cavity and held in place in a cyclic hydrogen-bonded network.

On heating, the alcohol is released in a single step. The kinetics of this decomposition reaction were studied using isothermal thermogravimetry. In both cases, desorption occurred by a diffusion-controlled mechanism. Kinetic parameters for the desorption reactions have been determined and compared.