Linear 2-Ethylhexyl Imidophosphoric Esters as Effective Rare-Earth Element Extractants

Applied Sciences

AndreyS. Esin¹  VyacheslavV. Kireev¹  AnnaA. Bykovskaya¹  NikolayS. Bredov¹  MikhailV. Gorlov¹  MariaD. Ryabochenko²  OksanaA. Sinegribova² 

[1] Department of Polymer Chemistry, Mendeleev University of Chemical Technology of Russia, Miusskaya sq. 9, 125047 Moscow, Russia;Department of Rare Elements and Nanomaterials Technology, Mendeleev University of Chemical Technology of Russia, Geroyev Panfilovtsev st. 20, 125480 Moscow, Russia;

关键词: imidophosphoric acids;    phosphazenes;    extractants;    2-ethylhexyl esters;    rare-earth elements;    living cationic polymerization;   

DOI  :  10.3390/app10041229

来源: DOAJ

【 摘 要 】

Imidophosphoric organic esters containing phosphoryl groups are potential polydentate ligands and promising extractants of rare-earth elements. For their preparation, a monophosphazene salt [PCl₃=N−PCl₃]⁺[PCl₆]⁻ and short phosphazene oligomers of the general formula [Cl−(PCl₂=N)_n−PCl₃]⁺[PCl₆]⁻, where n = 4−7, were synthesized via living cationic polymerization of Cl₃P=NSiMe₃ and used as starting compounds. All phosphazenes were reacted with 2-ethylhexanol to obtain the corresponding esters of imidophosphoric acids (EIPAs). The formation of imidophosphoric acids occurs due to the phosphazene-phosphazane rearrangement of −P(OR)₂=N− or −P(OH)(OR)=N− units, where R = 2-ethylhexyl. The prepared EIPAs were characterized by ¹H, ³¹P NMR, and MALDI-TOF analyses and their extractive capacity towards lanthanide ions in aqueous solutions of nitric acid was examined. The EIPAs are mixtures of mono-, di-, and trifunctional compounds of the type H_xA, where x = 1−3, which can form chelate complexes of lanthanide ions [Ln(A)_z], where z = 3−6, depending on the chain length. The longer chain EIPAs are more suitable for collective rare-earth elements extraction. A comparison of the extraction properties of the EIPAs with the industrially used polyalkylphosphonitrilic acid (PAPNA) was drawn.

【 授权许可】

Unknown