Separation of lithium and sodium is a topic of substantial scientific and industrial importance.
Regarding Li/Na perchlorates, which are not only environmental hazards but also useful oxidants in chemical synthesis, an efficient Li–Na perchlorate separation method has not been reported due to lack of a ligand which can selectively coordinate with one of the two.
Herein, we report an efficient Li–Na perchlorate separation by using our hexadentate ligand N,N′,N″-tris-(2-N-diethylaminoethyl)-1,4,7-triaza-cyclononane (DETAN), which can selectively coordinate with LiClO4 at room temperature to form a monomer in excellent yield but does not coordinate with NaClO4 even at elevated temperature.
The structure of the monomeric complex, [LiClO4(DETAN)] (1), was characterised by single-crystal X-ray diffraction and NMR spectroscopy.
With the concept demonstrated, further work is underway in three directions:
(i) to explore the influence of the anionic component, such as halides and pseudo-halides;
(ii) to modify the DETAN ligand with a variety of alkyl and aryl substituents and examine their separation performance;
(iii) to expand the scope to the aqueous environment, which is closer to the potential application scenario.
To read the paper in full, visit Non-aqueous separation of lithium and sodium perchlorates by selective coordination with a hexadentate semi-flexible amine ligand – Inorganic Chemistry Frontiers (RSC Publishing)
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