Darstellung und eigenschaften von austauschern auf basis von kronenverbindungen

Blasius, E.; Adrian, William J.; Janzen, K.‐P.; Klautke, G.

doi:10.1016/s0021-9673(01)81221-8

Cited by 96 publications

(7 citation statements)

References 6 publications

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“…It could, therefore, be expected that the complexing ability of 18-crown-6 rings will also enhance the solubility of the salts in the polymeric network. Indeed, experimental results supporting such expectations were already reported by Feingenbaum et al 3 and by Blessius et al 4 The solubility of salts in the polymer depends not only on the nature of the cation but also on its counter- ion. In the present study, values of partition coefficients were determined for NaC1, NaSCN, LiSCN, and water.…”

Section: Pc-6 Membranessupporting

confidence: 71%

Permeabilities to salts and water of macrocyclic polyether–polyamide membranes

Shchori

Jagur‐Grodzinski

1976

J of Applied Polymer Sci

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SynopsisThe polyether-polyamide (PC-6) strongly absorbs sodium salts from their aqueous solutions. Membranes based on PC-6 and on its polymeric alloys with poly(viny1pyrrolidone) (PVP) are, however, much more permeable to water than to salts. The membrane permselectivity is due to the low mobility of the absorbed salts. Desorption experiments were conducted to determine the values of the diffusion coefficients of the sodium ions in the investigated membranes. They were found to vary from 5 X cm2/sec in the polymeric alloy containing 30% PVP. Water permeation experiments with the alloy membranes yielded values of the diffusion coefficients in the range of 2-5 X lo-' cmz/sec. The apparent "energy,of activation of the diffusion" of sodium ions in such membranes was found to be essentially identical (-12 kcal) with the energy of activation of the decomplexation of the sodium-"crown" complex. The ramifications of the proposed "site to site jump" diffusion mechanism were discussed. The permeability characteristics of PC-6 membranes were found to be strongly affected by their "history." The observed phenomenon was explained in terms of reversible changes in the structure of the polymeric network, in the presence and in the absence of the absorbed salts. It has been found that PVP has a stabilizing effect on the permeability characteristics of the membranes. Reverse osmosis experiments indicated that their intrinsic osmotic characteristics seem to be superior to those of the commercially used materials. Their salt rejections are in the range of 95-99.5%, and their permeabilities to water are at least one order of magnitude higher than those of the unmodified aromatic polyamides. cm2/sec in loose PC-6 membranes to 1.7 X

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Section: Pc-6 Membranessupporting

confidence: 71%

Permeabilities to salts and water of macrocyclic polyether–polyamide membranes

Shchori

Jagur‐Grodzinski

1976

J of Applied Polymer Sci

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“…Preparation of l,3-Bis(o-methoxyphenoxy)-2-propoxyacetic Acid (4). The protecting mineral oil was removed by washing KH (28.32 g of 35% dispersion in mineral oil, 0.24 mol) with dry pentane under nitrogen and dry THF (200 mL) was added.…”

Section: Methodsmentioning

confidence: 99%

“…The diastereomeric methylene group protons on the threecarbon bridge of 6 appear as an AB quartet, which demonstrates that the conformation of that portion of the polyether ring is locked on the NMR time scale. The corresponding methylene group protons on the three-carbon bridges in monomers 4 and 5, from which resins 1 and 2, respectively, are prepared do not appear as AB quartets.…”

Section: Methodsmentioning

confidence: 99%

“…An attractive method to circumvent both problems is to incorporate the macrocyclic compound in a polymer network. Blasius and co-workers synthesized a series of crown ether resins by polycondensation reactions of dibenzo crown ethers with formaldehyde (4). These resins were used as stationary phases for the chromatographic separation of alkali-metal and * To whom correspondence should be addressed.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Selective sorption of alkali-metal cations by carboxylic acid resins containing acyclic or cyclic polyether units

Hayashita¹,

Goo²,

Lee³

et al. 1990

Anal. Chem.

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benzo group substituents. The selectlvltles and efficiencies of competitive alkali-metal cation sorption from aqueous solutions by these poly ether carboxylic acid resins are strongly Influenced by (1) the pH of the aqueous solution, (2) the acyclic or cyclic nature of the poly ether unit, and (3) the conformational positioning of the carboxylic acid group In the resins derived from cyclic polyether (crown ether) compounds. Good sorption selectivity for Na+ was observed for dibenzo-16crown-5 resin 3 In which the pendant carboxylic acid group Is oriented over the polyether cavity. Resin 3 was utilized as a stationary phase for selective column concentration of Na+ from dilute aqueous solution.

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“…Blasius et al (3) were the pioneers of applying crown ethers to chromatography. They chromatographed inorganic and organic ions over the complex forming exchangers with crown ethers or cryptands as anchor groups (3,4). Smulek and Lada prepared diatomaceous earth immobilized dibenzo-18-crown-6 and separated alkaline metal ions with it (5).…”

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confidence: 99%