Solvent extraction of alkali metal cations from aqueous solutions by highly lipophilic crown ether carboxylic acids

Liquid-liquid extraction of lithium using lipophilic dibenzo-14-crown-4 ether carboxylic acid in hydrophobic room temperature ionic liquid

“…4). A similar trend was also exhibited by previously reported CEs possessing carboxylic pendant side arms (Charewicz and Bartsch, 1982;Strzelbicki and Bartsch, 1981;Walkowiak et al, 1990;Ulewicz et al, 2006). At basic pH, the COOH group is deprotonated as COO -which resulted in stronger coordination of DB14C4-C18-COO − towards Li + (Onishi et al, 2010;Takahashi et al, 1991).…”

“…Meanwhile, the solubility of DB14C4 in hydrophobic RTIL CYPHOSIL 109 can be improved by tuning its lipophilicity (Bartsch et al, 1983;Walkowiak et al, 1990). With more lipophilic DB14C4, loss of the CE ligand to the aqueous phase can be minimized (Bartsch et al, 1983;Charewicz and Bartsch, 1982;Strzelbicki and Bartsch, 1981;Ulewicz et al, 2006;Walkowiak et al, 1990). Furthermore, increased CE loading in the RTIL would significantly enhance the Li + extraction capacity of the LLE system.…”

Effect of structural variations within lipophilic dibenzocrown ether carboxylic acids on the selectivity and efficiency of competitive alkali-metal cation solvent extraction into chloroform

“…I t was found that these proton-ionizable ionophores were of insufficient lipophilicity to remain completely in the organic phase during extraction of alkali-metal cations from alkaline aqueous phases. To avoid such complications in extraction behavior, a lipophilic group was attached either to each benzene ring or to the carboxylic acid containing sidearm of the dibenzo-16-crown-5 compound 2 to produce the lipophilic dibenzo-16-crown-5-carboxylic acids 4 and 5, respectively (3)(4)(5). Compounds 4 and 5 were found to be sufficiently lipophilic to remain completely in the chloroform phases even when the contacting aqueous solutions of alkali-metal cations were highly alkaline (3,5).…”

Effects of Solvent Type on Low-Temperature Sintering of Silver Oxide Paste to Form Electrically Conductive Silver Film

“…The two carbon bridges between the ether oxygens, the main structure of the solvents in Table I, is a typical chain structure of crown ether, which has regularly shown complexation with alkali and alkaline earth metal salts. [35][36][37][38][39][40] In the study of open chain analogs of crown ether podands, adequate lipophilicity was required for useful application of liquid membranes or organic solvents as phase-transfer agents, 41,42 and the lipophilicity can be regulated by attaching either aromatic residues or methyl pendants to the podand. 43 This also explains that the solubility trends in Table I could originate from the change in lipophilicity.…”