Thermal Behaviors of Aluminium Triisopropoxide Associates Manifested by Using DSC Method

Abstract

Aluminium triisopropoxide is a well known associate substance, and exists in trimeric, or tetrameric associate in crystal, or in solution. These associates in solid state are very stable and do not dissociate into monomers up to 200°C. Even in a solution, they do not dissociate upon adding a solvent or upon heating them at a high temperature. Thermal analyses were performed by using DSC. DSC curves of the crystalline aluminium triisopropoxide (ATP) show two endothermic peaks; the first is sharp and the second is broad. The observed differences among the first peaks, which are due to different crystallization procedures, suggest the. existence of two kinds of polymorphisms. In comparison with the first, the second peaks, appeared in two kinds of crystals, are in good agreement with each other and the occurence of the second ones reveals the presence of the markedly high binding energy in the intra-associate in preference to the inter-associate. Thus, DSC measurements manifested some interesting conclusions concerning the polymorphism, the dissociation of the associates, and the change in enthalpy and entropy.