Diphasic Acido-Basic Properties of Di(octylphenyl)phosphoric Acid (Doppa)

Uranium Permeation from Nitrate Medium Across Supported Liquid Membrane Containing Acidic Organophosphorous Extractants and their Mixtures with Neutral Oxodonors

“…Figure 2 shows that uranium transport across the membrane varied with their pKa values in the order: Cyanex 272 (8.7) > PC88A (7.1) > DNPPA (2.5) (25,32).…”

The role of polarizability in determining metal ion affinities in polymer-supported reagents: monoprotic phosphates and the effect of hydrogen bonding

“…The log D Eu(III) /pH plot has a slope of 1.4 with all points except the first (h0.98i) indicating that binding of Eu(NO 3 ) 2+ and Eu(NO 3 ) 2 + occurs in a ratio that releases 1.4 protons with an ion exchange mechanism similar to DPA but one that continues to be significant in the more acidic solutions despite the fact that phosphinic acids have a higher pK a than phosphonic acids. 37 Ion exchange with Eu 3+ is reasonable from 0.01 M HNO 3 . Additional P-OH moieties per ligand do not necessarily enhance the extent of ion exchange: e.g., monoprotic PA is known to have higher affinities than DPA despite its lower acidity.…”

Optimization of synergistic extraction of neodymium ions from monazite leach solution treatment via HFSLM using response surface methodology

“…The results follow the pKa values of the acidic organo-phosphorous extractants -which is the pKa values -of individual pKa values i.e. Cyanex 272 (pKa = 8.7), PC 88A (pKa = 7.1), D2EHPA (pKa = 4) and DNPPA (pKa = 2.5) (Dogmane et al, 2002;Sella et al, 1995). Similar observations have been reported on the extraction of neodymium ions from nitric acid medium using different acidic extractants (Dogmane et al, 2002).…”