• Journal of Industrial Technology
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• v.39 no.1
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• pp.41-45
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• 2019

Hydrogen sulfide ($H_2S$) is mainly produced along with methane and hydrocarbons in many gas fields as well as hydrodesulfurization processes of crude oils containing sulfur compounds and the emission of $H_2S$ has a considerable effect on both environmental problem and human health aspects due to formation of, e.g. acid rain and smog. In recent years, ionic liquids (ILs) have been proposed as the most promising solvents for $CO_2$ and hazardous pollutants capture, such as $H_2S$ and sulfur dioxide ($SO_2$). In this work, we demonstrate the use of the predictive COSMO-SAC model for the prediction of Henry's law constant of $H_2S$ in ILs. Furthermore, the method is used to screen for potential IL candidates for $H_2S$ capture from a set of 2,624 ILs formed from 82 cations and 32 anions. The effects of cation on the Henry's law constant of $H_2S$ such as (i) the variation of the alkyl chain length on cation, (ii) the substituent of methyl group ($-CH_3$) for H in C(2) position and (iii) the change of ring structure for cation family are clearly predicted by COSMO-SAC model.

• Applied Chemistry for Engineering
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• v.33 no.4
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• pp.394-401
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• 2022

The synthesis of 1,2-alkylaminopropanediols (1,2-AAPs) was designed to improve the hydrophilicity of linear 1,2-alkanediols having 10, 12, 14, and 16 carbon atoms in the alkyl chain. 1,2-AAPs were synthesized by reacting 3-monochloro-1,2-propanediol (3-MCPD) with linear alkylamines having 10, 12, 14 or 16 carbon atoms in an ethanol solvent at 40℃ for 2 h. The yield and purity of four types of 1,2-AAPs synthesized were found to be in the range of 51-58% and 85-99%, respectively. The amine salts of four types of 1,2-AAPs were prepared from a purified paste or solid compound by adding an acidic solution (HCl) to pH 7, and then their solubilities and antibacterial effects were tested. 1,2-decylaminopropanediol, 1,2-dodecylaminopropanediol, and 1,2-tetradecylaminopropanediol were all dissolved in water at concentrations of 100%, 50%, and 0.1%, respectively, however 1,2-hexadecylaminopropanediol was not. The antibacterial effect was improved as the length of the alkyl chain increased. As a result of confirming the preservative effect of the lotion (cosmetic formulation) applied with 1,2-AAP for application, it showed very strong antibacterial activity at low concentrations ranging from 0.005% to 0.2%.

• Journal of Adhesion and Interface
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• v.23 no.2
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• pp.53-58
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• 2022

Here, the surface characteristics of the dielectric were controlled by introducing the self-assembled monolayers (SAMs) as the intermediate layers on the surface of the AlOx dielectric, and the electrical performances of the organic charge modulated transistor (OCMFET) were significantly improved. The organic intermediate layer was applied to control the surface energy of the AlOx gate dielectric acting as a capacitor plate between the control gate (CG) and the floating gate (FG). By applying the intermediate layers on the gate dielectric surface, and the field-effect mobility (μ_OCMFET) of the OCMFET devices could be efficiently controlled. We used the four kinds of SAM materials, octadecylphosphonic acid (ODPA), butylphosphonic acid (BPA), (3-bromopropyl)phosphonic acid (BPPA), and (3-aminopropyl)phosphonic acid (APPA), and each μ_OCMFET was measured at 0.73, 0.41, 0.34, and 0.15 cm2V-1s-1, respectively. The results could be suggested that the characteristics of each organic SAM intermediate layer, such as the length of the alkyl chain and the type of functionalized end-group, can control the electrical performances of OCMFET devices and be supported to find the optimized fabrication conditions, as an efficient sensing platform device.

• Applied Chemistry for Engineering
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• v.9 no.1
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• pp.71-75
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• 1998

Liquid crystalline compounds with amine terminal group and related linear and cross-linked liquid crystal polymers with epoxy resin structure were synthesized and characterized to develope matrix materials for polymer dispersed liquid display applications. Both linear and crosslinked side chain type liquid crystal polymers made with aromatic amine mesogens and ethylene glycol diglycidyl ether exhibited nematic texture as shown by polarized optical microscope(POM) and their transition temperatures were determined both by DSC and POM. Liquid crystal polymer samples also showed even-odd effect as the spacer length of aromatic amine mesogens were varied, however, the effect was samller than that of low molecular weight mesogens. Changes of nematic-to-isotropic transition($T_{NI}$) of crosslinked type polymer liquid crystals were also disscussed in relation to the concentration change of crosslinking agent 1,10-diaminodecane.

• Journal of the Korean Applied Science and Technology
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• v.39 no.4
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• pp.488-498
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• 2022

The effects of 1,3-Butanediol, 1,2-Pentanediol, and 1,2-Hexanediol in surfactant solutions on cmc, surface tension, foaming and emulsifying properties were determined. The addition of diols in aqueous surfactant solution decreased cmc and surface tension, and enhanced the foaming and emulsifying power. This trend is more significant by the longer hydrocarbon chain length of the diols. This property was confirmed because the diol's alkyl chain and the hydrophobic interaction with the surfactant reduce the cohesive force of water and increase the interaction between the head groups of the surfactant at interface. In addition, MIC test was conducted to determine the preservative power of each diol, and as a result, the antibacterial activity was effective in the order of 1,2-HDO > 1,2-PDO > 1,3-BDO. The results of this study show that diol can be applied to cosmetics as an auxiliary surfactant and antibacterial agent.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.8 no.2
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• pp.77-85
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• 2022

The Td05 and Sgc8c, DNA-based aptamers, are well-known to target internalized surface markers (IGHM and PTK7) of Burkitt's lymphoma and acute lymphoblastic leukemia (ALL). Thus, Td05 and Sgc8c labeled with metallic radioisotope ⁶⁴Cu can be evaluated as potential diagnostic PET imaging agents. In this study, we modified the carbon chain length of the last adenosine of aptamer (n = 3, 6, 12) to increase tumor cell uptake and select the best candidate among six types of aptamer analogues and one adenosine of aptamer. After labeling of ⁶⁴Cu, [⁶⁴Cu]Cu-DOTA-aptamer analogues were evaluated in vitro studies (serum stability, Log P values, cell uptake, biodistribution). Then, we evaluate in vivo PET imaging study for two candidates (⁶⁴Cu-DOTA-C12-Sgc8c, ⁶⁴Cu-DOTA-C6-Td05). PET images clearly visualize tumors at 24 h post-injection rather than at an early time point and the tumor-to-background ratio also increases at the delay time point. ⁶⁴Cu-DOTA-C12-Sgc8c and ⁶⁴Cu-DOTA-C6-Td05 could be used as potential radiotracers for lymphoma.

• Clean Technology
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• v.16 no.4
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• pp.239-244
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• 2010

The carboxylation of the fluorenyl epoxide with a spiro framework, 9,9'-Bis(4-oxiranylmethoxyphenyl) fluorine (2) was catalyzed by some onium salts such as quaternary ammonium and phosphonium salts to produce the corresponding five-membered cyclic carbonate (3) in an efficient and environmentally benign fashion. The coupling reactions depend greatly on the kind of the halide anions and alkyl chain length of the onium salts. While the reaction was sensitive to the reaction temperature, the reaction trends suggest that the catalytic efficiency of the quaternary ammonium halides may correlate strongly with the melting points of the halides. The reactions using a catalytic amount (2 mol %) of quaternary ammonium bromide with an n-butyl chain at 75.9 bar of $CO_2$ and 393 K give the highest yield of the cyclic carbonate (92%).

• Membrane Journal
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• v.23 no.6
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• pp.450-459
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• 2013

2,3,5,6-Tetramethyl-1,4-phenylenediamine (TMPD) based polyimide (PI) were crosslinked with 1,2-Diaminoethane (DAE) and 1,6-Diaminohexane (DAH) to enhance gas transport properties. Fourier transform infrared (FT-IR) studies show that imide groups were converted into amide groups during crosslinking process. Thermogravimetric analysis (TGA) results indicate that the degradation temperature of crosslinked PI membranes decreased after crosslinking. This is due to degradation of alkyl group in crosslinking agent. The d-space of crosslinked PI membranes decreased with increasing crosslinking time. The ideal permeability for $CH_4$, $N_2$, $O_2$, and $CO_2$ decreased after crosslinking and the ideal permeability of crosslinked PI membranes induced by DAH is larger than that by DAE. In contrast, the permselectivity of $CO_2/CH_4$, $CO_2/N_2$ and $O_2/N_2$ increased during crosslinking. For the gas pair of $CO_2/CH_4$, the maximum increment is about 39.5% after 6 minutes of DAE crosslinking. Also, that of $O_2/N_2$ gas pair is about 20.5% after 6 minutes of DAE crosslinking. According to these result, DAE is more suitable for enhanced permselectivity than DAH. On the contrary, DAE is not useful for $CO_2/N_2$ separation due to reduction in $CO_2/N_2$ permselectivity after 3 minutes DAE crosslinking.

• Korean Journal of Crystallography
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• v.7 no.1
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• pp.8-19
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• 1996

Cholestryl Methyl and Propyl Carbonate(CH3OCOOC27H45, C3H7OCOOC27H45) are monoclinic, space group P21, with a=17.014(1), b=7.682(1), c=10.612(1)Å, β=103.05(1)°, Z=2, V=1351.16Å3, Dc=1.09 g/cm3 for methyl carbonate, and with a=13.683(1), b=11.864(2), c=18.904(2)Å, β=106.30(1)°, Z=4, V=2945.4Å3, Dc=1.06 g/cm3, Dm=1.06 g/cm3 for propyl carbonate. The intensity data were collected on an Enraf-Nonius CAD-4 diffractometer with a graphite monochromated Cu-Kα radiation. The structure was solved by direct methods and refined by full matrix least-squares methods. The final R factor was 0.051 for 2323 observed reflections for methyl carbonate and 0.074 for 3323 observed reflections for propyl carbonate. Compared with other cholesteryl derivatives, the cholesteryl ring and tail region of the molecules are normal. The molecules are stacked in clearly separated layers. At center of the layer, there are cholesteryl-C(17) side chain interactions. The interface region between layers is occupied by the loosely packed methyl carbonate chains. The structure of cholesteryl propyl carbonates have two propyl carbonates have two molecules(A, B) that are not related by crystal symmetry and have their tetracyclic system almost parallel to each other. Cholesteryl-cholesteryl interactions between symmetry related A-molecules, and cholesteryl-C(17) side chain interactions between symmetry related B-molecules occur at the center of the layers and these molecules stack along 2₁ screw axes. There are also C(17)chain-carbonate chain and C(17)chain-C(17)chain interactions in the interface region between layers. There is efficient packing between cholesteryl ring systems in propyl carbonates. Temperature ranges of cholesteric mesophases of cholesteryl alkyl cargonates are narrow for methyl, pentyl and hexyl carbonates, and rather broader for ethyl and propyl carbonates. Cholesteryl-isotropic transitions change very little with chain length.

• Journal of the Korean Applied Science and Technology
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• v.33 no.3
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• pp.449-458
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• 2016

Detergency and surface active properties of mixed anionic surfactants with amphoteric and nonionic were investigated. Sodium dodecyl sulfate (SDS) and ammonium dodecyl sulfate (ADS) as anionic surfactants and cocamidopropyl betaine (CAPB) as an amphoteric surfactant were used. Nonionic surfactants, which are butyl glucoside (BG), octyl glucoside (OG), decyl glucoside (DG), lauryl dimethylamine oxide (AO) and saponin were also used. To study the synergy effects of mixed SDS/ADS anionic surfactant systems, amphoteric and nonionic surfactants were added into the mixed anionic surfactants. Investigated properties of surfactant mixtures were critical micelle concentration (CMC), surface tension (${\gamma}$), wettability. In addition, based on these properties, detergency of each sample was examined. Surfactant mixtures are anionics (SDS/ADS), anionic/amphoteric/nonionic (SDS/ADS/CAPB/saponin), and anionic/nonionic (SDS/ADS/BG/saponin, SDS/ADS/OG/saponin, SDS/ADS/DG/saponin, and SDS/ADS/AO/saponin). With the addition of amphoteric and nonionic to mixed anionic surfactants, CMC and ${\gamma}$ were decreased. Addition of CAPB, which is amphoteric, showed the best property at CMC and ${\gamma}$. Furthermore, as the chain length of hydrocarbon in alkyl glucosides was increased, the CMC and ${\gamma}$ were enhanced. However, the wettability did not exactly match up with CMC and ${\gamma}$. The surfactant mixture, which contained DG, showed the best performance at wetting time. Detergency was measured at various temperatures ($15^{\circ}C$, $30^{\circ}C$, $50^{\circ}C$). The cleaning performance was enhanced by increasing washing temperature. Moreover, detergency was influenced by not only CMC and ${\gamma}$ but also wettability. Although CMC and ${\gamma}$ were not minimum at surfactant mixture that included DG, the best cleaning performance showed in that sample.