DETERMINATION OF PROTONATION CONSTANTS OF 2,2': 6',2'- TERPYRIDINE FROM LIQUID-LIQUID DISTRIBUTION DATA

摘要

Spent nuclear fuel is a problem that has to be dealt with in the future. Transmutation of the most dangerous long-lived radionuclides into other less harmful ones can be considered a complement to direct disposal in a repository. Separation of the interesting nuclides is an important issue and liquid-liquid extraction is a suitable technique to achieve the necessary separation yields. One group of extractants that can be used is oligopyridines and in this work basic research to determine the protonation constants of 2,2':6',2"-terpyridine has been performed. Results show that complexes with up to three hydrogen atoms, bound to the terpyridine molecule, exist. Terpyridine forms a strong complex with Cu(II)-ions, which facilitate spectrophotometric determination of the distribution of terpyridine between the two phases. This distribution, measured at different pH-values in the aqueous phase, makes it possible to determine the protonation constants.