AN EXPERIMENTAL-TECHNIQUE TO DETERMINE THE COMPLEX STABILITIES OF NEARLY INSOLUBLE DIBENZO CROWN-ETHERS WITH AMMONIUM AND ALKYLAMMONIUM IONS IN AQUEOUS-SOLUTION

A new spectrophotometric method was used to determine the stability co nstants for the reaction of ammonium and alkylammonium ions with nearl y insoluble ligands in aqueous solution. As ligands some dibenzo crown ethers were used. They are only poorly soluble in aqueous solutions. Due to the complex formation the total concentration of the ligand in solution increases. Dibenzo crown ethers show an absorption band in th e ultraviolet spectral range. Therefore, it becomes possible to detect the increasing total concentration of the ligands. From these experim ental data the stability constants of the complexes formed can be calc ulated under certain assumptions. The main advantage of this method is that only small amounts of the ligands are necessary to determine the stability constants in homogeneous solution.