• Korean Chemical Engineering Research
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• v.56 no.6
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• pp.909-913
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• 2018

A hydrocarbon trap (HT) plays an important role of controlling vehicle emissions in the so-called cold emission period by holding hydrocarbons until three way catalysts (TWCs) are thermally activated. In this study, we have investigated the adsorption characteristics of cation (H, La, K, and Ag)-exchanged ZSM-5 zeolites for hydrocarbons (propylene, n-butane, and toluene) by DFT (density functional theory)-based computational chemistry. Cation exchange is to improve the hydrothermal stability of zeolites and their adsorption capacity, thereby rendering cation-exchanged zeolites promising materials for HT. The idea of cluster approximation makes the calculation of adsorption energies superbly efficient in computation. The results showed that Ag-exchanged ZSM-5 would be the best for the adsorption of all three adsorbates, without often encountered Ag oxidation in experiments. Besides, the hydrothermal stability of La-exchanged ZSM-5 was confirmed from the change of geometrical parameters by cation exchange, and it showed good adsorption capacity for propylene and toluene. Hydrogen-exchanged ZSM-5 was also good for hydrogen adsorption, but had poor hydrothermal stability.

• Journal of the Korean Chemical Society
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• v.31 no.2
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• pp.190-196
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• 1987

The structure of 9-barbaralyl cation was examined by Hammett-Brown plot using $^{13}C$ NMR chemical shifts. 9-Aryltricylclo$[3.3.1.0^{2,8}]$]nonan-9-yl cation (5) and 9-aryltricyclo-$[3.3.1.0^{2,8}]$nona-3,6-dien-9-yl cation (6) were prepared from the corresponding carbinols in $FSO_3H-SO_2ClF$ solution at -$120^{\circ}C$, and their chemical shifts of cation centers were measured. The slopes, ${\rho}^{C+}$ values, of the Hammett-Brown plot of (5) and (6) were -5.01 and -7.52, respectively. From these values themselves, it seemed that the double bonds participated in the delocalization of the positive charge. However, comparing ${\rho}^{C+}$ value and ${\rho}^{C_a^+}$ value in 9-barbaralyl cation (6) and those in 8,9-dehydroadamantyl cation (7), we concluded that 9-barbaralyl should be represented by the structure 4 shown in Scheme I.

• Membrane Journal
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• v.21 no.2
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• pp.141-147
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• 2011

The cation exchange membrane using TPA (tungstophosphoric acid) and the block co-polymer of polysulfone and polyphenylenesulfidesulfone was prepared for a separator of all-vanadium redox flow battery. The membrane resistance of the prepared cation exchange membrane in 1mol/L $H_2SO_4$ aqueous solution was measured. The membrane resistance of the prepared Psf-PPSS and Psf-TPA-PPSS cation exchange membrane was about $0.94{\Omega}{\cdot}cm^2$. Electrochemical property of all-vanadium redox flow battery using the prepared cation exchange membrane was measured. The measured charge-discharge cell resistance of V-RFB at 4 A decreased in the order; Nafion117 < Psf-TPA-PPSS < Psf-PPSS. The durability of membrane was earried out by soaking it in $VO_2{^+}$ solution and evaluated by measuring the charge-discharge cell resistance of V-RFB with an increase of soaking time. The prepared Psf-PPSS cation exchange membrane had high durability and Psf-TPA-PPSS cation exchange membrane had almost same durability compared with Nafion117.

• Bulletin of the Korean Chemical Society
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• v.35 no.3
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• pp.775-782
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• 2014

The importance of including spin-orbit interactions for the correct description of structures and vibrational frequencies of haloiodomethanes is demonstrated by density functional theory calculations with spin-orbit relativistic effective core potentials (SO-DFT). The vibrational frequencies and the molecular geometries obtained by SO-DFT calculations do not match with the experimental results as well as for other cations without significant relativistic effects. In this sense, the present data can be considered as a guideline in the development of the relativistic quantum chemical methods. The influence of spin-orbit effects on the bending frequency of the cation could well be recognized by comparing the experimental and calculated results for $CH_2BrI$ and $CH_2ClI$ cations. Spin-orbit effects on the geometries and vibrational frequencies of $CH_2XI$ (X=F, Cl, Br, and I) neutral are negligible except that C-I bond lengths of haloiodomethane neutral is slightly increased by the inclusion of spin-orbit effects. The $^2A^{\prime}$ and $^2A^{{\prime}{\prime}}$ states were found in the cations of haloiodomethanes and mix due to the spin-orbit interactions and generate two $^2E_{1/2}$ fine-structure states. The geometries of $CH_2XI^+$ (X=F and Cl) from SO-DFT calculations are roughly in the middle of two cation geometries from DFT calculations since two cation states of $CH_2XI$ (X=F and Cl) from DFT calculations are energetically close enough to mix two cation states. The geometries of $CH_2XI^+$ (X=Br and I) from SO-DFT calculations are close to that of the most stable cation from DFT calculations since two cation states of $CH_2XI$(X=Br and I) from DFT calculations are energetically well separated near the fine-structure state minimum.

• Bulletin of the Korean Chemical Society
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• v.11 no.4
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• pp.276-281
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• 1990

The equivalent conductance of univalent cation (potassium, silver, thallium and ammonium) perchlorates in methanol containing 18-membered crown ethers, 18-crown-6 (18C6) and 1,10-dithia-18-crown-6 (DT18C6) were measured at different temperatures. The equivalent conductances of ammonium perchlorate were increased by increasing content of DT18C6 exceptionally, due to more favorable solvations than complexations. From the equivalent conductance changes, the formation constants for 1:1 compmlexes have been determined, and the values of enthalpy and entropy changes have been calculated. The complexations of 18C6 and DT18C6 with the univalent cations under investigation are all exothermic and the ${\Delta}$S values are all negative and no considerable differences around 50 J/ (k mol). The selectivity order of 18C6 is $K^+ > Tl^+ > Ag^+ > NH_4^+$, while that of DT18C6 is $Ag^+ > Tl^+ > NH_4^+ > K^+$. By sulfur substitutions in 18C6 result in significant decrease in stability, but the stability of $Ag^+$-DT18C6 complex are $10^4$ times larger than those of $K^+$. This increase of stabilities for $Ag^+$-DT18C6 complex are primary due to the result of favorable exothermic heat of reaction between the polarizable soft cation and soft sulfur centers. In NMR experiment, the stepwise additions of cation perchlorates into crown ether solutions induced two major spectral changes. First, the resonance all shift down field and the cation induced shifts were linear up to 1:1 cation/crown ratio, above which no further changes were observed. On the basis of these results, it could be concluded that 1:1 complex is formed. Second, the magnitudes of cation induced shifts were different each other in same ligand. By addition of silver ion to the solution of DT18C6, the largest shift of proton peak near the sulfur atom was observed. These effects are also arisen from the results of covalent bonding between "soft-soft" interactions.

• Bulletin of the Korean Chemical Society
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• v.28 no.2
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• pp.319-321
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• 2007

• Korean Journal of Mineralogy and Petrology
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• v.35 no.3
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• pp.345-353
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• 2022

This study aimed to fundamentally understand changes of cell parameters of cation-exchanged mordenites using high resolution X-ray powder diffraction for studies that immobilization of various heavy metal cation using synthesis mordenite (Na_6.6Al_6.6Si_41.4O₉₆·20.4H₂O, Na-MOR). As a results of measurement by Thermogravimetric analysis (TGA), it was confirmed that 19.4, 20.4 water molecules per unit cell were present in monovalent-cation substituted MOR (Cs-MOR, Na-MOR), and 21, 23.1, 23.2 water molecules per unit cell were present in divalent-cation substituted MOR (Pb-MOR, Sr-MOR, Cd-MOR). The space group of all the samples were identified as Cmcm belonging to the orthorhombic crystal system. Compared to Na-MOR, starting material, relative peak intensity of (110) and (200) is significantly changed after cation substitution whereas peak position is almost similar. Also, (220) peak that was not found in Na-MOR was clearly observed in Pb-, Cd- and Sr-exchanged MOR. Thus, it was estimated that changes of atomic distribution usually occurred on ab-plane while changes of cell parameters were little. Detailed changes in the cell parameters of cation-exchanged mordenites were derived from whole profile fitting method using the GSAS suite program. Changes in the axial lengths and unit cell volume of cation substitution showed different relationship depending on ionic radius and charge number. In case of monovalent-cation substituted MOR, the length of a-axis increases whereas the length of b- and c-axis decrease by absorbed cation radius. In the case of divalent-cation exchanged MOR, the length of a-axis usually decreases while the length of b- and c-axis increases by cation radius. It was confirmed that unit cell volume of monovalent and divalent cation substituted MORs had an independent tendency by cation radius.

• Korean Journal of Soil Science and Fertilizer
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• v.6 no.3
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• pp.193-197
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• 1973

1. Two desert perennial plant species (Lycium andersonii Gray and Atriplex confertifolia (Torr. & Frem) Wats.) were grown in soil in a glasshouse with different sources of Na ($NO_3{^-}$, $Cl^-$, $H_2PO_4{^-}$) to evaluate their effects upon cation-anion balance in the plants. 2. Each anion greatly increased in leaf with only minor, if any, interactions with other anions 3. The miliequivalent sum of anions measured (N. P. Cl), increased in each plant part with the soil applications. 4. Simultaneously there were usually modest increases in the me. sum of cations. 5. The cation-anion ratio was decreased markedly when $NaNO_3$ was added. The ratio was usually over one. 6. Maximum content of Cl and N in leaves with L. andersonii. was 13.5%, and 6.37% respectively, when each was added. 7. Sodium concentrations were higher for the Atriplex species than for L. andersonii. 8. There were some compensations among other cations as sodium was increased, so that a somewhat constant sum of cations was maintained although there were significant differences among different sources of Na. 9. L. andersonii appeared to be an accumulator of Li.

• Journal of Acupuncture Research
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• v.18 no.4
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• pp.143-151
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• 2001

Objective : This study was undertaken to determine whether Scutellaria balicalensis Georgi (SbG) extract exerts the protective effect against oxidant-induced alterations in organic cation transport in the renal proximal tubule. Methods : Organic cation transport was estimated by examining alterations in tetraethylammon - ium(TEA) uptake in rabbit renal cortical slices. The slices were treated with 0.2 mM tBHP for 60 min at $37^{\circ}C$. tBHP caused an inhibition in TEA uptake by renal cortical slices. Such an effect was accompanied by depressed Na+-K+-ATPase activity and ATP depletion. tBHP also induced a significant increase in LDH release. Results : SbG prevented tBHP-induced inhibition of TEA uptake in a dose-dependent manner at the concentration ranges of 0.05-0.1%. tBHP-induced inhibition of Na+-K+-ATPase activity and ATP depletion were significantly prevented by 0.05% SbG. tBHP-induced LDH release also was blocked by SbG. tBHP caused a significant increase in lipid peroxidation and its effect was prevented by SbG. Conclusion : These results suggest that SbG prevents oxidant-induced alterations in organic cation transport in rabbit renal cortical slices. Such protective effects of SbG may be attributed to inhibition of peroxidation of membrane lipid.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.5
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• pp.314-319
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• 2015

In this research, we focused on the development of cy3 dye with high thermal stability and good solubility for LCD color filter. Cy3 dyes were prepared through the synthetic procedure of two steps. The synthesized cy3 dyes were characterized by using NMR, FT-IR, UV/Vis spectroscopy, and TGA. These cy3 dyes showed maximum absorption wave length (${\lambda}_{max}$) in the range of 549~555 nm in UV/Vis spectrum. And we confirmed that solubility characteristics and thermal stability of cy3 dyes were dependent on the structure of counter cation. Cy3 dyes with methyl counter cation and ethyl counter cation have good solubility in organic solvents such as chloroform, ethanol, and PGME. Moreover, Cy3 dye with ethyl counter cation gave excellent thermal stability in TGA thermograms. And Cy3 dye with ethyl counter cation showed good result in photoresist film test.