Extractants nitrogen donor

The marked tendency for cobalt(II) to become oxidized to cobalt(III) after its extraction by hydroxyoximes is well known, and results from the large decrease in redox potential of the Co2+/Co3+ couple in the presence of nitrogen donor ligands... 

Musikas, C. 1984. Actinide-lanthanide group separation using sulfur and nitrogen donor extractant. In Actinide/Lanthanide Separations, eds. G.R. Choppin, J.D. Navratil, W.W. Schulz, pp. 19-30. World Scientific, Singapore. 

Some new extractants were not soluble in alkanes thus, a long-chain alcohol like n-octanol had to be selected. The degradation of the diglycolamide TODGA was similar for n-octanol and dodecane solutions (182,183). With polyaromatic nitrogen donors like the /Pr-BTP molecule, a similar hydrolysis effect was measured in pure w-octanol and alkane-octanol (70-30% in volume) (244). 

These oxygen-donor type extractants have potential for co-extraction of trivalent lanthanide and actinide ions. For the mutual separation between trivalent actinides and lanthanides, so-called soft-donor (nitrogen-donor type and sulfur-donor type) extractants are promising and widely investigated for the application of nuclear waste treatment as follows. 

BTP, BTBP system. Kolarik et al. (1999, 2008) and Madic et al. (2000) carried out comprehensive study of the separation of trivalent actinides from lanthanides by the nitrogen donor extractants. They developed several new nitrogen polydentate ligands, BTP [2,6-bis(5,6-dialkyl-l,2,4-triazin-3-yl)-4-alkyl-pyridines] and BTBP [6,6 -bis-(5,6-diethyl-[l,2,4]triazin-3-yl)-2,2 -bipyridyl] see O Fig. 18.22). 

The possible physiological role of ammonia as a nitrogen donor for ribosylamine phosphate synthesis has been studied and debated. Although ammonia can react nonenzymatically with PP-ribose-P to form riboiqrl-amine phosphate (IS), it can also react enzymatically to form this product in cell extracts (H, 15) and in intact cells (16, 17). Although most work supports the role of PP-ribose-P amidotransferase as the enzyme involved, Reem (18) has put forward evidence that a separate enzyme might use ammonia exclusively. 

The combination of sulfur and nitrogen donor atoms in crown ethers appears to provide an ideal binding site for Hg + as several sensors, mainly electrochemical, which use azathiacrown ethers to target the metal have been reported. The selectivity for mercury over other metals is often astonishingly high. " A 15-crown-5 C-pivot lariat ether incorporating a thioether side chain was found to extract 46% of Hg + from aqueous solution into dichloroethane, although it was also able to remove almost 100% of Ag+ under the same conditions. ... 

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