• Title/Summary/Keyword: Green Chemistry

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Phenol Hydroxylation over TS-1 Synthesized by Hydrothermal and Microwave Heating Method: Solvent Dependence (수열 합성법과 마이크로파 가열법으로 제조한 TS-1 촉매에 의한 페놀 수산화 반응: 용매의 영향)

  • Kwon, Song-Yi;Yoon, Song-Hun;Lee, Jong-Min;Chang, Jong-San;Lee, Chul-Wee
    • Korean Chemical Engineering Research
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    • v.49 no.2
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    • pp.151-154
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    • 2011
  • Catalytic activity such as conversion and selectivity on the phenol hydroxylation over TS-1 prepared by hydrothermal method and microwave heating method, respectively, was compared and discussed for understanding the dependence of solvent such as water, methanol, acetone, respectively, during phenol hydroxylation, with hydrogen peroxide. Basic physical properties such as XRD, EDS, SEM and $N_{2}$ adsorption/desorption were determined and compared. The relationship between catalytic activity and physical properties of TS-1 was explained.

Optimization of Anthraquinone Dyes Decolorization Conditions with Response Surface Methodology by Aspergillus

  • Ge, Yufeng;Wei, Bin;Wang, Siyu;Guo, Zhiguo;Xu, Xiaolin
    • Korean Chemical Engineering Research
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    • v.53 no.3
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    • pp.327-332
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    • 2015
  • A large amount of dye wastewater poses a threat to environmental safety. Disperse blue, an anthraquinone dye that is widely used in textile dyes, is difficult to degrade in wastewater. In this work, one fungus was screened according to the decolorization rate of disperse blue. The fungus was identified and named Aspergillus XJ-2 on the basis of its morphological characteristics and 18s rDNA. Response surface method was used to optimize culture conditions for A. XJ-2. The optimum values of obtained responses were as follows: temperature, $35^{\circ}C$; pH, 5.2; carbon-to-nitrogen ratio, 30:5.5; and rotation ratio, $175r{\cdot}min^{-1}$. Under optimized conditions, the decolorization rate of A. XJ-2 was up to 94.8% in 48 h.

Styrene Epoxidation over Cobalt Cyclam Immobilized SBA-15 Catalyst

  • Sujandi;Prasetyanto, Eko Adi;Han, Sang-Cheol;Park, Sang-Eon
    • Bulletin of the Korean Chemical Society
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    • v.27 no.9
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    • pp.1381-1385
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    • 2006
  • Cobalt (cyclam) complex has been successfully immobilized onto SBA-15, and proven to be an active catalyst for the epoxidation of styrene with tert-butyl hydroperoxide as a terminal oxidant. The selectivity for styrene oxide was observed to be up to 66% with 40% styrene conversion after 12h reaction time. The reversible redox cycle between Co(III) and Co(II) couple which was supposed to play key role during the epoxidation reaction was supported by a cyclic voltametry analysis. The textural properties of the catalyst was characterized by XRD, N2 adsorption-desorption, and TEM analysis.

Green Synthesis of Silver and Gold Nanoparticles Using Lonicera Japonica Flower Extract

  • Nagajyothi, P.C.;Lee, Seong-Eon;An, Minh;Lee, Kap-Duk
    • Bulletin of the Korean Chemical Society
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    • v.33 no.8
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    • pp.2609-2612
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    • 2012
  • A simple green method was developed for rapid synthesis of silver and gold nanoparticles (AgNPs and AuNPs) has been reported using Lonicera japonica flower extract as a reducing and a capping agent. AgNPs and AuNPs were carried out at $70^{\circ}C$. The successful formation of AgNPs and AuNPs have been confirmed by UV-Vis spectro photometer, fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), energy dispersive X-ray Analysis (EDAX), scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). To our knowledge, this is the first report where Lonicera japonica flower was found to be a suitable plant source for the green synthesis of AgNPs and AuNPs.

Origin of Green Emission in Extremely Pure Oligofluorene Films: Effect of Molecular Packing

  • Kang, Ji-Hoon;Shin, Na-Yool;Jo Jung-Ho;Keivanidis Panagiotis E.;Laquai Frederic;Wegner Gerhard;Yoon, Do-Y.
    • Proceedings of the Polymer Society of Korea Conference
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    • 2006.10a
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    • pp.236-236
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    • 2006
  • Time-resolved photoluminescence spectroscopy measurements of oligofluorenes with various side chains were studied. With extremely pure oligofluorenes, two kinds of red-shifted green emission were observed which have different origins; aggregate formation and on-chain chemical defect. The green emission around 490 nm was largely dependent upon the intermolecular interaction of oliglfuorene molecules. Moreover, by using oligofluorene with high-order liquid crystalline phase, we observed that the green emission was strongly dependent upon the molecular packing in solid films.

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Microwave Synthesis of Hydrotalcite by Urea Hydrolysis

  • Yang, Zhiqiang;Choi, Kwang-Min;Jiang, Nanzhe;Park, Sang-Eon
    • Bulletin of the Korean Chemical Society
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    • v.28 no.11
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    • pp.2029-2033
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    • 2007
  • Hydrotalcite, layered double hydroxides (LDH), with hexagonal morphology has been rapidly synthesized by microwave reaction within 1 hour by urea hydrolysis from homogeneous solution. Different synthesis parameters, Mg/Al molar ratio, microwave reaction temperature and microwave power were systematically investigated. Pure hydrotalcite phase was obtained for Mg/Al ratios of 2:1 and 3:1, and higher reaction temperature gave higher crystallinity. The hydrotalcite synthesized at 600W power shows the highest crystallinity and more homogeneous crystal size distribution. The hydrotalcite samples were characterized by powder X-ray diffraction (XRD), simultaneous thermogravimetric/differential thermal analysis (TG/DTA), Fourier Transform Infrared (FT-IR) and Scanning electron micrograph (SEM).

Industrial Utilization and Outlook on Nanoporous Materials (나노세공체 촉매소재의 산업적 활용과 전망)

  • Chang, Jong-San;Hwang, Young Kyu;Park, Yong-Ki;Choi, Won Choon
    • Prospectives of Industrial Chemistry
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    • v.17 no.2
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    • pp.8-20
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    • 2014
  • 나노세공체는 고표면적, 균일한 다공성, 분자크기의 세공구조, 높은 흡착용량, 이온교환 특성, 높은 촉매활성, 분자크기의 형상선택성 등의 특징을 갖기 때문에 촉매 및 흡착제로 나노소재 분야에서 가장 오랫동안 활용되어 왔던 중요한 물질 가운데 하나로 정유 및 석유화학 산업을 비롯한 화학산업과 환경 산업에 광범위하게 사용되고 있다. 본 고찰에서는 결정성 나노세공체 가운데 가장 중요한 제올라이트와 최근 연구가 활발한 하이브리드 나노세공체의 산업적 응용 및 기술개발 동향과 향후 발전 전망에 대해 간략히 기술하였다.

Highly Sensitive Luminescence Assessment of Bile Acid Using a Balofloxacin-Europium(III) Probe in Micellar Medium

  • Cai, Huan;Zhao, Fang;Si, Hailin;Zhang, Shuaishuai;Wang, Chunchun;Qi, Peirong
    • Bulletin of the Korean Chemical Society
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    • v.33 no.12
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    • pp.4145-4149
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    • 2012
  • A novel and simple method of luminescence enhancement effect for the determination of trace amounts of bile acid was proposed. The procedure was based on the luminescence intensity of the balofloxacin-europium(III) complex that could be strongly enhanced by bile acid in the presence of sodium dodecyl benzene sulfonate (SDBS). Under the optimum conditions, the enhanced luminescence intensity of the system exhibited a good linear relationship with the bile acid concentration in the range $5.0{\times}10^{-9}-7.0{\times}10^{-7}\;mol\;L^{-1}$ with a detection limit of $1.3{\times}10^{-9}\;mol\;L^{-1}$ ($3{\sigma}$). The relative standard deviation (RSD) was 1.7% (n = 11) for $5.0{\times}10^{-8}\;mol\;L^{-1}$ bile acid. The applicability of the method to the determination of bile acid was demonstrated by investigating the effect of potential interferences and by analyzing human serum and urine samples. The possible enhancement mechanism of luminescence intensity in balofloxacin-europium(III)-bile acid-SDBS system was also discussed briefly.