Dielectric Study on the Water of Crystallization of Berberine Chloride

Abstract

There are two types of water of crystallization in the crystallive state of berberine chloride. This fact was confirmed by the measurements of dielectric and thermal behaviors in the processes of adsorption and desorption isotherms. The anhydrous berberine chloride was very hygroscopic, absorbed moisture immediately, and was transformed to dihydrate even at low relative humidity. On the other hand, dihydrate was not so hygroscopic but it was transformed to tetrahydrate at relatively high humidity. The dihydrate has low values of apparent dielectric constant and apparent dielectric loss, but the tetra-hydrate showed dielectric dispersion at low frequencies. The tetrahydrate has two endothermal peaks in the desorption process of thermal analysis. The activation energies of the two peaks were small values of 12.6 and 15.9 kcal/mol, respectively. It means that the two kinds of water of crystallization in berberine chloride are not stable for the change of temperature.