Macrocyclic carriers in supported liquid membranes

Abstract

Macrocyclic receptor molecules can be designed to selectively bind a variety of host molecules, including metal cations and neutral molecules. This property can be uniquely exploited in separation processes, by using these compounds as carriers in transport through liquid membranes. The various types of liquid membrane systems are briefly discussed, and the attractive features of the supported (by a microporous polymer film) liquid membrane (SLM) are explained. The mechanical stability of the SLMs is dependent on several factors, including the type of polymer support, membrane solvent, and hydrophobicity of the carrier used. The rates and selectivity of transport are discussed in terms of membrane geometry, membrane solvent type, structure and concentration of the carrier, and the type and concentration of cations, and anions in both the source and receiving phases. Existing mathematical models in which these parameters have been incorporated, are compared with experimental data. Apart from a concentration gradient of the metal cation over the membrane, other driving forces, such as anion concentration, proton counter‐transport and redox‐active transport, are discussed.

1,3‐Alternate Calix[4]arenecrown‐5 Conformers: New Synthetic Ionophores with Better K+/Na+ Selectivity than Valinomycin

“…'HNMR (250MH2,CDCl,,25°C. TMS): 6 =7.13 (d,'J(H,H) =7.4Hz,4 H ;25,27-Bis(Z-propyloxy)calix [4]arenecrown-5, partial cone (11): To a solution of 9 (0.40 g, 0.68 mmol) and 2-iodopropane (0.68 mL, 6.86 mmol) in dry THF (20 mL), a suspension of potassium terr-butoxide (0.31 g, 2.74 mmol) in dry THF (20 mL) was added. The reaction mixture was refluxed for 12 h. Then THF was removed under reduced pressure and the residue quenched with 3 N HCI.…”

A supported liquid membrane (SLM) with resorcinarene for facilitated transport of methyl glycopyranosides: Parameters and mechanism relating to the transport

“…Calixarene derivatives have been increasingly used as carriers in liquid membranes, essentially for the extraction of metal ions [5,6]. More generally, the use of various types of macrocyclic carriers in SLM is well documented [7].…”

E laboration of macrocyclic membranes based β - cyclodextrin by physical mixing and these application to dialysis organic molecules.

“…In the case of our system t L = 4000s for phenol and t L = 3000s for glucose. The obtained results (Table 3) allow use to offer a growing classification of the diffusion of organic molecules, while a geometric point of view, the inclusion will depend on the relative size of the cavity of the cyclodextrin from the size of the diffused molecule [16]. For if the molecule is too large in size, it can not penetrate inside the cavity of the cage molecule, against if its size is too small, it will have little interaction with the macrocyle cyclodextrin.…”

“…The studied membranes were prepared according to the phase inversion process and more specifically precipitation by solvent evaporation [20][21][22][23][24][25][26][27]. In this method, 130 mg of methylated-allylated β-CD or methylated β-CD and 100 mg of cellulose triacetate polymer are dissolved of chloroform by magnetic stirring.…”