Extraction properties of diglycolamide for rare earth: Contribution of N-substituents

A successful extraction process relies heavily on an excellent extractant structure. The theory of extractant structure and extraction performance is still insufficient to guide the design of new extractants, despite extensive research into extractants. However, diglycolamide extractants have demonstrated certain advantages in nuclear fuel reprocessing and rare earth extraction and separation. This paper focuses on the synthesis of 13 structurally serially changed extractants. There is a good connection between the extraction performance and the energy consumption of the carbonyl conformation torsion of the extractant with symmetrical straight-chain alkyl substituents. The extraction capacity of extractant decreases with the increase of alkyl chain length. The methyl substituent extractant shows higher extractability than the other. The steric effect of the alkyl chain with more than two carbons is not significantly different. The relationship between the structure and performance of extractants was systematically studied by the combination of theoretical calculations and experimental data to investigate the effects of symmetric, asymmetric and branched N-substituents on extraction performance. (c) 2024 Chinese Society of Rare Earths. Published by Elsevier B.V. All rights are reserved, including those for text and data mining, AI training, and similar technologies.