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Insights into the Coordination and Extraction of Yttrium(III) Ions with a Phenoxyacetic Acid Ionic‐Liquid Extractant
Author(s) -
Guo XiangGuang,
Yang RuoOu,
Gong Yu,
Jiang Zheng,
Dong Yamin,
Sun Xiaoqi
Publication year - 2017
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201601491
Subject(s) - chemistry , bifunctional , extended x ray absorption fine structure , yttrium , ionic liquid , extraction (chemistry) , ionic bonding , coordination complex , inorganic chemistry , coordination number , chloride , crystal structure , crystallography , absorption spectroscopy , ion , organic chemistry , metal , catalysis , oxide , physics , quantum mechanics
Phenoxyacetic acid type extractants such as sec ‐octylphenoxyacetic acid (CA‐12), sec ‐nonylphenoxyacetic acid (CA‐100), and the resulting bifunctional ionic‐liquid extractants were developed to separate yttrium from heavy rare‐earth elements (REEs). To obtain information on the coordination chemistry of this type of bifunctional ionic‐liquid extractant, the CA‐12 analogue n ‐octylphenoxyacetic acid (HOCTPOA) was synthesized, and its structure was characterized by single‐crystal X‐ray diffraction analysis. Then, a bifunctional ionic‐liquid extractant based on HOCTPOA, namely, [N 1888 ][OCTPOA] (N 1888 is methyltrioctylammonium) was synthesized. The study of the extraction of yttrium with [N 1888 ][OCTPOA] in chloride media was conducted by IR spectroscopy, log D versus log C slope analysis, ESI‐MS, extended X‐ray absorption fine structure (EXAFS), and DFT studies. The EXAFS data indicate that a Y III extraction complex with phenoxyacetic acid formed. Three possible Y III coordination cations were calculated by the DFT method, and the obtained Y–O bond lengths were comparable to the results from EXAFS fitting. A possible structure for the overall extracted complex was proposed, and this knowledge should contribute to a better understanding of the extraction process with phenoxyacetate‐type bifunctional ionic liquids.