Membrane transport of alkali metals with phosphorylmethyl derivatives of amino acids

Abstract

Membrane technologies, including transport of alkali metal ions through impregnated liquid membranes [1] are widely utilized nowadays in processing of sources and wastes of alkali metals, above all lithium. We have earlier demonstrated that lipophilic α-aminophosphine oxides are efficient carriers of rare and trace elements through liquid supported membranes; however, alkali metal ions are retained in the feed aqueous phase under conditions of the membrane extraction [2]. Herein we present the data on membrane extraction of alkali metal ions (Li, Na, and K) using the lipophilic bismethylphosphorylated derivatives of glycine (I, n = 1) and β-alanine (II, n = 2) [(C 8 H 17 ) 2 P(O)CH 2 ] 2 N(CH 2 ) n COOH as transmembrane carriers. The measured transmembrane flows are shown in the table.According to the obtained data, both amino acid derivatives acted as efficient transmembrane carriers of all alkali metal ions from neutral and weakly alkaline feed phases, in contrast to the earlier studied neutral aminophosphoryl extracting agents. At the same time, no selectivity towards lithium transport (earlier demonstrated when using the synergetic carrier, equimolar mixture of N,N-bis(dihexylphosphorylmethyl)octylamine and phosphorus dioctylmonothioacid or dioctyldithioacid [3]) was observed in this work. The carrier II was more efficient in the alkaline medium, giving rise to six-fold higher transport flows as compared to the carrier I under the same conditions. When pH of the feed phase was decreased, all the transport flows aided by compound I incresed almost three times; again, no selectivity towards any of the ions was observed. Noteworthily, the ability of the studied carriers towards membrane extraction of the alkali metal ions from neutral medium is their important advantage over the membrane system based on β-diketones and trioctylphosphine oxide, the latter being capable only of lithium extraction from the alkaline solutions [4]. As pH of underground and sea

6. Synthesis of α-aminophosphonates by the Kabachnik–Fields reaction and by the Pudovik reaction

“…According to the literature, double Kabachnik-Fields reactions are usually carried out in various solvents, without any catalyst [84][85][86][87][88][89][90][91]. Nowadays, green chemical approaches, such as the catalyst-and solvent-free MW-assisted syntheses, have also became more and more popular [77,[92][93][94][95][96].…”

“…Amino acid derivatives may also be the starting materials in the Kabachnik- The reactions of long-chain amino acids with 2 equivalents of paraformaldehyde and dimethyl or dioctyl phosphite were also described ( Table 6.4) [88,89]. The condensations were performed in THF or in acetonitrile, and the corresponding bis(α-aminophosphonates) were obtained in 81-95% yields.…”