Effect of permeation temperature on permeation and separation of a benzene/cyclohexane mixture through liquid-crystalline polymer membranes

Inui, Kuniaki; Miyata, Takashi; Uragami, Tadashi

doi:10.1002/(sici)1099-0488(19980130)36:2<281::aid-polb7>3.0.co;2-u

Cited by 21 publications

(16 citation statements)

References 2 publications

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“…The activation energy for permeation, a measure of the barrier to transport due to interactions between the enantiomers and the LC phase, was determined from transport measurements at different temperatures. The activation energy was obtained from the slope of an Arrhenius plot of transport experiments at different temperatures in the cholesteric phase (Fig. ):

P = P_{0} exp (\frac{- E_{a}}{R T})

where P is the permeation coefficient or permeability (m 2 /s), R is the ideal gas constant (8.314 J/mol K), T is the temperature (K), E a is the activation energy for permeation (kJ/mol), and P 0 is the Arrhenius constant (m 2 /s).…”

Section: Resultsmentioning

confidence: 99%

“…The activation energy for permeation, a measure of the barrier to transport due to interactions between the enantiomers and the LC phase, was determined from transport measurements at different temperatures. The activation energy was obtained from the slope of an Arrhenius plot 25,31 of transport experiments at different temperatures in the cholesteric phase ( Fig. 6):…”

Section: The Effect Of Temperature On 1-phenylethanol and Phenylglycimentioning

confidence: 99%

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Enantioselective separations using chiral supported liquid crystalline membranes

et al. 2012

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Porous and nonporous supported liquid crystalline membranes were produced by impregnating porous cellulose nitrate supports with cholesteric liquid crystal (LC) materials consisting of 4-cyano-4'-pentylbiphenyl (5CB) mixed with a cholesterol-based dopant (cholesteryl oleyl carbonate [COC], cholesteryl nonanoate [CN], or cholesteryl chloride [CC]). The membranes exhibit selectivity for R-phenylglycine and R-1-phenylethanol because of increased interactions between the S enantiomers and the left-handed cholesteric phase. The selectivity of both phenylglycine and 1-phenylethanol in 5CB/CN membranes decreases with effective pore diameter while the permeabilities increase, as expected. Phenylglycine, which is insoluble in the LC phase, exhibits no transport in the nonporous (completely filled) membranes; however, 1-phenylethanol, which is soluble in the LC phase, exhibits transport but negligible enantioselectivity. The enantioselectivity for 1-phenylethanol was higher (1.20 in 5CB/COC and 5CB/CN membranes) and the permeability was lower in the cholesteric phase than in the isotropic phase. Enantioselectivity was also higher in the 5CB/COC cholesteric phase than in the nematic phase of undoped 5CB (1.03). Enantioselectivity in the cholesteric phase of 5CB doped with CC (1.1), a dopant lacking hydrogen bonding groups, was lower than in the 5CB/COC phases. Finally, enantioselectivity increases with the dopant concentration up to a plateau value at approximately 17 mol%.

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P = P_{0} exp (\frac{- E_{a}}{R T})

Section: Resultsmentioning

confidence: 99%

“…The activation energy for permeation, a measure of the barrier to transport due to interactions between the enantiomers and the LC phase, was determined from transport measurements at different temperatures. The activation energy was obtained from the slope of an Arrhenius plot 25,31 of transport experiments at different temperatures in the cholesteric phase ( Fig. 6):…”

Section: The Effect Of Temperature On 1-phenylethanol and Phenylglycimentioning

confidence: 99%

Enantioselective separations using chiral supported liquid crystalline membranes

et al. 2012

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“…Water purification by membrane filtration is a low-cost and energy-saving method of obtaining high-quality water. − Ordered nanochannels with uniform sizes are essential for achieving high-quality water-treatment membranes . Self-assembly of polymerizable liquid crystals − ,,,− and copolymers − that form nanochannels and nanopores of uniform size has been used for the preparation of functional polymer materials. Self-assembled materials with one-dimensional (1D), 2D, and 3D nanochannels (channel size: 0.5–2 nm) are obtained from nanostructured liquid crystals exhibiting columnar (Col), smectic (Sm), and bicontinuous cubic (Cub bi ) phases, respectively. ,, Block copolymers also form 1D, 2D, and 3D nanochannels (channel size: 5–50 nm). − LC nanostructured polymeric materials have been successfully applied as water-treatment membranes, − organic molecular adsorbents, ,,− and ion conductors. ,,,, …”

Section: Introductionmentioning

confidence: 99%

Gemini Thermotropic Smectic Liquid Crystals for Two-Dimensional Nanostructured Water-Treatment Membranes

Hamaguchi

Ichikawa

Kajiyama

et al. 2021

ACS Appl. Mater. Interfaces

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We have developed a two-dimensional (2D) liquidcrystalline (LC) nanostructured water-treatment membrane showing high virus rejection ability (over 99.99997% for bacteriophage Qβ) and improved water permeation. Polymerizable gemini amphiphiles have been designed and synthesized. They have H-shaped gemini-type structures of thermotropic smectic liquid crystals composed of cationic imidazolium moieties. One of the gemini amphiphiles shows a smectic A phase with an interdigitated bilayer structure. A cross-linked self-standing 2D nanostructured polymer film has been obtained by in situ photopolymerization of the gemini amphiphile in the smectic phase. The length of linkers in gemini amphiphiles affects the formation of LC phases. The 2D nanostructured membrane also showed selective salt rejection.

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“…Investigations of the selective pervaporation of volatile organic compounds and the enantioselective properties of cholesteric liquid crystalline membranes have been reported [13,14,15,16]. In addition, there have been several studies of side-chain LCPs focusing on the relationship between polymer microstructure and transport properties [17,18,19,20,21,22].…”

Section: Introductionmentioning

confidence: 99%

Temperature-Dependent Gas Transport Behavior in Cross-Linked Liquid Crystalline Polyacrylate Membranes

et al. 2019

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Stable, cross-linked, liquid crystalline polymer (LCP) films for membrane separation applications have been fabricated from the mesogenic monomer 11-(4-cyanobiphenyl-4′-yloxy) undecyl methacrylate (CNBPh), non-mesogenic monomer 2-ethylhexyl acrylate (2-EHA), and cross-linker ethylene glycol dimethacrylate (EGDMA) using an in-situ free radical polymerization technique with UV initiation. The phase behavior of the LCP membranes was characterized using differential scanning calorimetry (DSC) and X-ray scattering, and indicated the formation of a nematic liquid crystalline (LC) phase above the glass transition temperature. The single gas transport behavior of CO2, CH4, propane, and propylene in the cross-linked LCP membranes was investigated for a range of temperatures in the LC mesophase and the isotropic phase. Solubility of the gases was dependent not only on the condensability in the LC mesophase, but also on favorable molecular interactions of penetrant gas molecules exhibiting a charge separation, such as CO2 and propylene, with the ordered polar mesogenic side chains of the LCP. Selectivities for various gas pairs generally decreased with increasing temperature and were discontinuous across the nematic–sotropic transition. Sorption behavior of CO2 and propylene exhibited a significant change due to a decrease in favorable intermolecular interactions in the disordered isotropic phase. Higher cross-link densities in the membrane generally led to decreased selectivity at low temperatures when the main chain motion was limited by the lack of mesogen mobility in the ordered nematic phase. However, at higher temperatures, increasing the cross-link density increased selectivity as the cross-links acted to limit chain mobility. Mixed gas permeation measurements for propylene and propane showed close agreement with the results of the single gas permeation experiments.

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Effect of permeation temperature on permeation and separation of a benzene/cyclohexane mixture through liquid-crystalline polymer membranes

Cited by 21 publications

References 2 publications

Enantioselective separations using chiral supported liquid crystalline membranes

Enantioselective separations using chiral supported liquid crystalline membranes

Gemini Thermotropic Smectic Liquid Crystals for Two-Dimensional Nanostructured Water-Treatment Membranes

Temperature-Dependent Gas Transport Behavior in Cross-Linked Liquid Crystalline Polyacrylate Membranes

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