• Bulletin of the Korean Chemical Society
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• v.8 no.4
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• pp.242-246
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• 1987

The hydrogen abstraction reactions of $SiH_4, SiH_2Cl_2 \;and\; SiHCl_3$ by ground state chlorine atoms generated photochemically from chlorine molecules have been studied at temperatures between 15 and $100^{\circ}C.$ The absolute rates for the reactions have been obtained by a competition technique using ethane as a competitor. The rate expressions ($in cm^3/mol/s$) are found to conform to an Arrhenius rate law: $k_{SiH_4} = (7.98 {\pm} 0.42) {\times} 10^{13}$ exp $[-(1250 {\pm}20)/T].$ $k_{SiH_2Cl_2} = (2.25 {\pm} 0.12) {\times} 10^{15}$ exp[-(1010 ${\pm}$ 10)/T]. $k_{SiHCl_3} = (9.04 {\pm} 0.28) {\times} 10^{14}\; exp[-(1200 {\pm} 10)/T].$ The activation energies obtained from this study represent the same trend as with the carbon analogues, while this trend was not found with respect to the bond dissociation energies among silicon compound homologues. These anomalous behaviors were interpreted in terms of electronic effects and of the structural differences between these compounds.

• Bulletin of the Korean Chemical Society
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• v.17 no.2
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• pp.173-179
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• 1996

A series of tetradentate Schiff base ligands; [1,2-bis(naphthylideneimino)ethane, 1,3-bis(naphthylideneimino)propane, 1,4-bis(naphthylideneimino)butane, and 1,5-bis(naphthylideneimino)pentane] and their Ni(Ⅱ) complexes have been synthesized. The properties of these ligands and their Ni(Ⅱ) complexes have been characterized by elemental analysis, IR, NMR, UV-vis spectra, molar conductance, and thermogravimetric analysis. The mole ratio of Schiff base to Ni(Ⅱ) metal was found to be 1:1. The electrochemical redox process of the ligands and their Ni(Ⅱ) complexes in DMF and DMSO solution containing 0.1 M tetraethyl ammonium perchlorate (TEAP) as a supporting electrolyte have been investigated by cyclic voltammetry, chronoamperometry, differential pulse voltammetry, and controlled potential coulometry at glassy carbon electrode. The redox process of the ligands was highly irreversible, whereas redox process of Ni(Ⅱ) complexes were observed as one electron transfer process in quasi-reversible and diffusion-controlled reaction. The electrochemical redox potentials of the Ni(Ⅱ) complexes were affected by the chelate ring size of ligands. The diffusion coefficients of Ni(Ⅱ) complexes containing 0.1 M TEAP in DMSO solution were determined to be 5.7-6.9 × 10-6 cm2/sec. Also the exchange rate constants were determined to be 1.8-9.5 × 10-2 cm2/sec. These values were affected by the chelate ring size of ligands.

• The Journal of Industrial Distribution & Business
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• v.14 no.4
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• pp.23-31
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• 2023

Purpose: Gas firms often fall victim to disregarding the importance of sensitivity, thus leading to many unprecedented repercussions. To ensure that gas firms fully contribute to sustainability and ethical standards, environmental Social Governance (ESG) has been identified as the ideal framework. This study aims to investigate the impact of ESG management for improving gas firm performance. Research design, data and methodology: The prior qualitative literature analysis was to figure out adequate past research for the topic based on the major portal web databased, such as 'Google Scholar' and 'Scopus' to make sure resources' credibility. Results: Gas firms are among the pertinent organizations vis-à-vis environmental destruction issues. Gas firms emit dangerous gases such as ethane, carbon dioxide and methane that are dangerous for the people and the environment. Thus, many pro-environmental conservation stakeholders have had rallying calls for such gas firms to mitigate environmental pollution intentionally. Conclusions: This study may be used to human resources in improving employee results elsewhere. Besides, it can be of the essence in improving the relationship between such firms and society. Therefore, the study findings are of greater significance and implications to multiple parties, users and stakeholders regarding the research topic and beyond the current scope of the study.

• Archives of Pharmacal Research
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• v.19 no.4
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• pp.286-291
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• 1996

Phenolic compounds are prevalent as toxins or environmental pollutants, but they are also widely used as drugs for various purpose including anticancer agent. A novel biphenolic compound, bis(2-hydroxy-3-tert-butyl-5-methylphenyl)methane (GERI-BPO02-A) was isolated from the fermentation broth of Aspergillus fumigatus F93 previously, and it has revealed cytotoxicity against human solid tumor cells. Its effective doses that cause 50% inhibition of cell growth in vitro against non-small cell lung cancer cell A549, ovarian cancer cell SK-OV-3, skin cancer cell SK-MEL-2 and central nerve system cancer cell XF498 were 8.24, 10.60, 8.83, $9.85\mug/ml$ respectively. GERI-BPO02-A has also revealed cytotoxicity against P-glycoproteinexpressed human colon cancer cell HCT15 and its multidrug-resistant subline HCT15/CL02, and its cytotoxicity was not affected by P-glycoprotein. We have also tested cytotoxicities of structurally related compounds of GERI-BPO02-A such as diphenylmethane, 1,1-bis(3,4dimethylphenyl)ethane, 2,2-diphenylpropane, 2-benzylpyridine, 3-benzylpyridine, $4,4^I-di-tert-butylphenyl$, bibenzyl, $2,2^I-dimethylbibenzyl$, cis-stilbene, trans-stilbene, 3-tert-butyl-4-hydroxy-5-methylphenyisulfide, sulfadiazine and sulfisomidine for studying of structure and activity relationship, and from these data we could suppose that hydroxyl group of GERI-BPO02A conducted important role in its cytotoxicity.

• Journal of Korean Society for Atmospheric Environment
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• v.19 no.4
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• pp.387-396
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• 2003

A field study was conducted during the summer time of 2002 to determine compositions of volatile organic compounds (VOCs) emitted from vehicles and to develop source emission profiles that is applied to CMB model to estimate the source contribution of certain area. Source emission profile is widely used for the estimation of source contribution by the chemical mass balance model and have to be developed applicable for the target area of estimation. This study was aimed to develop source emission profile and estimation of source contribution of VOCs after application of the chemical mass balance (CMB) receptor model. After considering the emission inventory and other research results for the VOCs in Seoul, Korea, the sources like vehicle emission (tunnel), gas station (gasoline, diesel), solvent usage (painting operation, dry cleaning, graphic art), and gas fuels were selected for the major VOCs sources. Furthermore, ambient air samples were simultaneously collected from 09:00 to 11:00 for four days at eight different official air quality monitoring sites as receptors in Seoul during summer of 2001. Source samples were collected by canisters, and then about seventy volatile organic compounds were analyzed by gas chromatography with flame ionization detector (GC/FID). Based on both the developed source profiles and the database of the receptors, CMB model was intensively applied to estimate mass contribution of VOCs sources. Examining the source profile from the vehicle, the portion of alkanes of VOCs was highest, and then the portion of aromatics such toluene, m/p-xylene were followed. In case of gas fuel. they have their own components; the content of butane, propane, ethane was higher than any other component according to the fuel usage. The average of the source apportionment on VOCs for 8 sites showed that the major sources were vehicle emission and gas fuels. The vehicle emission source was revealed as having the highest contribution with an average of 49.6%, and followed by solvent with 21.3%, gas fuel with 16.1%, gasoline with 13.1%.

• KSBB Journal
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• v.11 no.2
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• pp.246-253
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• 1996

An obligatory methanotroph Methylosinus trichosporium OB3b was cultivated for the production of poly-${\beta}$-hydroxybutyric acid(PHB) in shake-flask using liquefied natural gas(LNG) as the sole source of carbon and energy. The maximal specific growth rate decreased by 40% using LNG compared with that obtained with pure methane. This is attributed to the inhibition by ethane and propane presents in the LNG as impurities. For the production of PHB, two-stage culture separating the production stage from the growth stage was carried out. PHB accumulation was observed after switching nutrient-sufficient to nutrient-limited condition of non-carboneous component (NO3-, PO43-, K+, Na+, Fe2+, or Mg2+). The limitation of K+ or Mg2+ resulted in relatively high PHB content, but the highest content was obtained by nitrate limitation. The optimal pH and temperature for PHB accumulation was 7.0 and $30^{\circ}C$. Under the optimal condition the maximal PHB content was about 45% after 4-day cultivation.

• Applied Chemistry for Engineering
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• v.9 no.1
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• pp.94-100
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• 1998

Methane, the major constituent of natural gas, had been converted to higher hydrocarbons by a microwave plasma. The yield of C2+ product could be increased from 29.2% to 42.2% with increasing plasma power(40~120 watt) and decreasing flow rate(40~5 mL/min) of methane. With catalyst, the selectivities of ethylene and increased while yield of C2+ remaining constant. Among various catalysts, Fe catalyst showed the highest ethylene selectivity of 30%. A natural gas could produce more C2+ than a pure methane. This is due to high reactivity of ethane and propane in the natural gas.

• Journal of Korean Society for Atmospheric Environment
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• v.30 no.1
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• pp.77-87
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• 2014

In this study, an experimental approach to measure a suite of low weight hydrocarbons was investigated with an emphasis on ethylene (EL) along with many others (ethane (EA), propane (PA), propylene (PL), n-butane (BA), acetylene (AL), methyl acetylene (ML)). Their concentrations were quantified using GC-FID system equipped with thermal desorption (TD) system. The TD-based analysis was conducted using both Link Tube/Thermal Desorber (LT/TD) method and Modified Injection through a Thermal Desorption (MITD) method. The results of these analyses were evaluated in a number of respects. The system allowed the detection of all compounds except methane with the mean response factor (RF) of 10.28 (EA) to 11.94 (PL). The method detection limits of target compounds were seen in the range of 0.027 (ML) to 0.146 ng (BA). The emission flux of some environmental samples (fruits), when measured using a small flux chamber system, fell in the range of 0.14 (AL: Kiwi) to $181ng{\cdot}g^{-1}{\cdot}hr^{-1}$ (EL: Apple Peel). The results of this study confirm that the experimental approach developed in this study allows to accurately measure emissions of low weight hydrocarbons (LWHC) like ethylene from various natural and man-made source processes.

• Biomolecules & Therapeutics
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• v.5 no.2
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• pp.125-132
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• 1997

Cisplatin, a platinum-complex, is currently one of the most effective compounds used in the treat-ment of solid tumors. However, its use is limited by severe side effects such as renal toxicity. Our platinum-based drug discovery program is aimed at developing drugs capable of diminishing toxicity and improving selective cytotoxicity. We synthesized new Pt (II) complex analogue containing 1,2-diaminocyclohexane (DACH) as carrier ligand and 1,2-bis (diphenylphosphino) ethane (DPPE) as a leaving group. Furthermore, nitrate was added to improve the solubility. A new series of [Pt(cia-DACH)(DPPE)] . $2NO_3$ (PC) was synthes-ized and characterized by their elemental analysis and by various spectroscopic techniques [infrared (IR), $_{13}$carbon nuclear magnetic resonance (NMR)] .PC demonstrated acceptable and significant antitumor activity against SKOV-3 and OVCAR-3 human ovarian carcinoma cell lines as compared with that of cisplatin. The cytotoxicity of PC in normal cells was found quite less than that of cisplatin using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), ($^3$H)thymidine uptake and glucose consumption tests in rabbit renal proximal tubular cells, human renal cortical cells and tissues. In conclusion, PC is considered to be more selective cytotoxicity toward human ovarian cancer cells than normal human/rabbit kidney cells.

• Journal of Korea Soil Environment Society
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• v.4 no.3
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• pp.85-93
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• 1999

The destruction of hazardous chemicals such as chlorinated organic compounds(COCs) and nitroaromatic compounds(NACs) by zero-valent iron powder is one of the latest innovative technologies. In this paper. the rapid dechlorination of chlorinated compounds as well as transformation of nitro functional group to amine functional group in the nitroaromatic compounds using synthesized zero-valent iron powder with nanoscale were studied in anaerobic batch system. Nanoscale iron, characterized by high surface area to mass ratios(31.4$\textrm{m}^2$/g) and high reactivity, could quickly reacts with compounds such as TCE, chloroform, nitrobenzene, nitrotoluene, dinitrobenzene and dinitrotoluene, at concentration of 10mg/L in aqueous solution at room temperature and pressure. In this study, the TCE was dechlorinated to ethane and chloroform to methane and nitro groups in NACs were transformed to amino groups in less than 30min. These results indicated that this chemical method using nanoscale iron powder has the high potential for the remediation of soils and groundwater contaminated with hazardous toxic chemicals including chlorinated organic compounds and nitro aromatic compounds.