Membrane Transport and Extraction Properties of Hexyl [(N-Methyl-N,N-dioctylammonio)methyl]phosphonate

Abstract— The membrane transport properties of lipophilic phosphorylated betaine, hexyl [(N-methyl-N,N-dioctylammonio)methyl]phosphonate, and of industrial extractant trioctylphosphine oxide were studied. The selectivity of the transport of rare-earth metal ions by both carriers was revealed. Hexyl [(N-methyl-N,N-dioctylammonio)methyl]phosphonate proved to be more effective than the industrial carrier with respect to triply charged rare-earth metal ions, in particular, lanthanum, neodymium, and europium ions. According to the IR spectral data, under the conditions of liquid-liquid extraction in 1,2-dichlorobenzene, complexes with singly and doubly charged metal ions are not formed, while complexation with rare-earth metal nitrates occurs with participation of the phosphonate moiety of the phosphorylated betaine; in the metal complexes, the nitrate anion acts as a counterion.