Microwave-assisted synthesis of dialkylphosphinic acids and a structure–reactivity study in rare earth metal extraction

Abstract

Dialkylphosphinic acids were synthesized efficiently under microwave irradiation. The extractants with ethyl or propyl substituents at the β-position showed higher separation efficiency.

Extraction Behavior of Acidic Phosphorus-Containing Compounds to Some Metal Ions: A Combination Research of Experimental and Theoretical Investigations

“…49 Namely, the ΔG EX and K EX are difficult to calculate. Consequently, in previous reports, 47,48 a simplified chemical reaction…”

“…As indicated in our previous reports, ΔG EX,1 and K EX,1 calculated from density functional theory (DFT) share the same trend with ΔG EX and K EX tested from the experimental approach. 47,48 Therefore, ΔG EX,1 is also applied to estimate ΔG EX in the trend in this work, as shown as Figure 1. The distorted conformation was adopted for the ligand in [Co(H 2 O) 5 A] (o) + to reflect the steric effect of alkyl group in extractants, especially the αor β-substituted alkyl group.…”

“…Therefore, it is still highly desirable to develop more efficient extractants. We have previously developed an approach to evaluate the QSPR for the separation and extraction of several trivalent lanthanide ions by APCC from the theoretical and experimental point of view. , Various APCCs were synthesized and characterized, and their extraction and separation properties under different conditions were also tested. The first-stability constants were used to simulate the overall extraction equilibrium constants in trend.…”

Synthesis of High Purity Nonsymmetric Dialkylphosphinic Acid Extractants

“…The class of dialkylphosphinic acid extractants is considered to be one of the most important research aspects to develop new extractants. Recent research showed that the extraction ability of dialkylphosphinic acids depends largely on the structure of the alkyl substituent 10,11 . It can be a wide range from significantly higher than that of P507 to lower than that of Cyanex 272 12 .…”

“…It can be a wide range from significantly higher than that of P507 to lower than that of Cyanex 272 12 . However, the exploration of novel dialkylphosphinic acid extractants is restricted to the commercial olefin structure 10,12,13,14,15,16 . Though dialkylphosphinic acid extractants can also be synthesized by the Grignard-reaction method, the reaction conditions are rigorous 12,17 .…”