• Title/Summary/Keyword: Styrene Oxide

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Synthesis of Cyclic Styrene Carbonate via Pyrolysis of Poly(styrene carbonate) (Poly(styrene carbonate)의 열분해에 의한 고리형 Styrene Carbonate의 합성)

  • Yoo, Jin-Li;Shin, Eun-Jung;Koo, Dae-Chul;Lee, Yoon-Bae
    • Proceedings of the KAIS Fall Conference
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    • 2006.05a
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    • pp.569-571
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    • 2006
  • 지구의 온난화를 가속시키는 주요물질인 이산화탄소($CO_2$)와 styrene oxide를 Zinc Glutarate를 촉매로 하여 800-1000psi, $750^{\circ}C$에서 반응시켜 합성한 Poly(styrene carbonate)(PSC)를 질소분위기하 $750^{\circ}C$에서 열분해하여 고리형 styrene carbonate를 합성하였다. 생성물은 GC-Mass로 분석하여 확인하였다.

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A Cold-Adapted Epoxide Hydrolase from a Strict Marine Bacterium, Sphingophyxis alaskensis

  • Kang, Ji-Hyun;Woo, Jung-Hee;Kang, Sung-Gyun;Hwang, Young-Ok;Kim, Sang-Jin
    • Journal of Microbiology and Biotechnology
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    • v.18 no.8
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    • pp.1445-1452
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    • 2008
  • An open reading frame (ORF) encoding a putative epoxide hydrolase (EHase) was identified by analyzing the genome sequence of Sphingophyxis alaskensis. The EHase gene (seh) was cloned and expressed in E. coli. To facilitate purification, the gene was fused in-frame to 6$\times$ histidine at the C-terminus. The recombinant EHase (rSEH) was highly soluble and could be purified to apparent homogeneity by one step of metal affinity chromatography. The purified SEH displayed hydrolyzing activities toward various epoxides such as styrene oxide, glycidyl phenyl ether, epoxyhexane, epoxybutane, epichlorohydrin, and epifluorohydrin. The optimum activity toward styrene oxide was observed at pH 6.5 and $35^{\circ}C$. The purified SEH showed a cold-adapted property, displaying more than 40% of activity at low temperature of $10^{\circ}C$ compared with the optimum activity. Despite the catalytic efficiency, the purified SEH did not hydrolyze various epoxides enantioselectively. $K_m$ and $k_{cat}$ of SEH toward (R)-styrene oxide were calculated as 4$\pm$0.3 mM and 7.42$s^{-1}$ respectively, whereas $K_m$ and $k_{cat}$ of SEH toward (S)-styrene oxide were 5.25$\pm$0.3 mM and 10.08$s^{-1}$ respectively.

Bioinformatics based Identification and Characterization of Epoxide Hydrolase of Gordonia westfalica for the Production of Chiral Epoxides (Bioinformatics를 활용한 토양미생물인 Gordonia westfalica Epoxide Hydrolase 생촉매 개발 및 Chiral Epoxides 제조 특성 분석)

  • Lee Soo Jung;Lee Eun Jung;Kim Hee Sook;Lee Eun Yeol
    • KSBB Journal
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    • v.20 no.4
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    • pp.311-316
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    • 2005
  • Epoxide hydrolases (EHs) are versatile biocatalysts for the preparation of chiral epoxides by enantioselective hydrolysis from racemic epoxides. Various microorganisms were identified to possess a EH activity by multiple sequence alignment and analysis of conserved domain sequence from genomic and megaplasmid sequence data. We successfully isolated Gordonia westfalica possessing EH activity from various microbial strains from culture type collections. G. westfalica exhibited (R)-styrene oxide preferred enantioselective hydrolysis activity. Chiral (S)-styrene oxide with high optical purity $(>\;99\%)\;ee)$ and yield of $36.5\%$ was obtained from its racemate using whole-cell of G. westfalica.

Dehydrogenation of Ethylbenzene with Carbon Dioxide as Soft Oxidant over Supported Vanadium-Antimony Oxide Catalyst

  • Hong, Do-Young;Vislovskiy, Vladislav P.;Park, Sang-Eon;Park, Min-Seok;Yoo, Jin-S.;Chang, Jong-San
    • Bulletin of the Korean Chemical Society
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    • v.26 no.11
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    • pp.1743-1748
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    • 2005
  • This work presents that carbon dioxide, which is a main contributor to the global warming effect, could be utilized as a selective oxidant in the oxidative dehydrogenation of ethylbenzene. The dehydrogenation of ethylbenzene over alumina-supported vanadium-antimony oxide catalyst has been studied under different atmospheres such as inert nitrogen, steam, oxygen or carbon dioxide as diluent or oxidant. Among them, the addition of carbon dioxide gave the highest styrene yield (up to 82%) and styrene selectivity (up to 97%) along with stable activity. Carbon dioxide could play a beneficial role of a selective oxidant in the improvement of the catalytic behavior through the oxidative pathway.

Evaluation of Microbial Epoxide Hydrolase Activity Based on Colorimetric Assay Using 4-(p-nitrobenzyl) Pyridine (4-(p-Nitrobenzyl)pyridine의 색깔반응을 이용한 미생물 epoxide hydrolase의 활성 평가)

  • Kim Hee Sook;Lee Eun Yeol
    • Journal of Life Science
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    • v.15 no.3 s.70
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    • pp.332-336
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    • 2005
  • Epoxide hydrolase activities of various microbial cells were analyzed by colorimetric assay based on alkylation of epoxides with 4-(p-nitrobenzyl)pyridine (NBP). The epoxide hydrolase activity was determined by measuring the decrease of color intensity at 560 nm due to the decrease of styrene oxide substrate by epoxide hydrolase-catalyzed hydrolysis reaction. The experimental conditions of NBP colorimetric assay were optimized for the efficient measurement of epoxide hydrolase activities from various microbial cells.

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.

A Study on Graphene Oxide and Carboxylated Styrene-Butadiene Rubber(XSBR) Nanocomposites (그래핀 옥사이드/카르복실화한 스티렌-부타디엔 고무 나노 복합체에 관한 연구)

  • Jang, Sun Ho;Xu, Li Xiang;Cho, Ur Ryong
    • Journal of the Semiconductor & Display Technology
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    • v.16 no.1
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    • pp.52-58
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    • 2017
  • Graphene oxide (GO)/carboxylated styrene-butadiene rubber (XSBR) nanocomposites with various contents of GO were prepared by a latex compounding method. It has been confirmed that the functional groups of GO and the hydrogen bonds between GO and XSBR are existed. It can be seen that the scorch time ($t_{s2}$), which is the measurement of incipient vulcanization of rubber, showed a delay after the addition of GO. Field emission scanning electron microscopy was employed to confirm the uniform dispersion of filler in the matrix. Indeed, with increasing fillers loading, the torque, tensile strength, thermal stability and crosslink density of obtained nanocomposites were improved. These results were correlated to the better dispersion of fillers through the rubber matrix.

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Improvement of Abrasion and Debris on Styrene-Butadiene-Styrene Block Copolymer with Carboxylated SBR Latex and Zinc Oxide (카르복실화 SBR 라텍스와 산화아연을 이용한 SBS의 내마모성과 데브리스(debris) 개선 연구)

  • Lee, Jin Hyok;Bae, Jong Woo;Kim, Jung Su;Yoon, Yoo-Mi;Jo, Nam-Ju
    • Elastomers and Composites
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    • v.48 no.3
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    • pp.225-231
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    • 2013
  • In this study, we observed the effect of carboxylated SBR latex and zinc oxide on styrene-butadiene-styrene( SBS) composites for improving abrasion and debris. SBS composite, which added only silica, showed poor mechanical properties, NBS abrasion, and debris, caused by strong filler-filler interaction of silica. In case of adding carboxylated SBR latex, mechanical properties, NBS abrasion and debris of SBS composite were improved. Because of carboxyl group of carboxylated SBR latex interacted with silanol group of silica. Both carboxylated SBR latex and zinc oxide were added, SBS composite showed highest mechanical properties, NBS abrasion, and debris by forming ion cluster between carboxylated SBR latex and zinc oxide. By FT-IR analysis, ion clusters were confirmed that observed zinc carboxylated group stretch peak at $1550{\sim}1650cm^{-1}$ range. SBS composite, SC-4, showed excellent mechanical properties ; tensile strength $156kgf/cm^2$, elongation 936%, tear strength 59.4kgf/cm ; and excellent abrasion characteristics ; NBS abrasion 338%. Also, debris of SC-4 was minimized and showed wave-shape in fracture surface.

Synthesis of Poly(styrene carbonate) and Preparation of Styrene Carbonate by Thermal Degradation (Poly(styrene carbonate)의 합성 및 열분해에 의한 styrene carbonate의 제조)

  • Lee, Yoon Bae;Shin, Eun Jung;Yoo, Jin Yi
    • Applied Chemistry for Engineering
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    • v.19 no.1
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    • pp.133-136
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    • 2008
  • In order to decrease carbon dioxide, one of the green house gas, poly(styrene carbonate) has been synthesized from carbon dioxide and styrene oxide with zinc glutarate as a catalyst. The polymer has been identified as an alternating copolymer by spectroscopic analysis, FT-IR, $^1H$-NMR, and $^{13}C$-NMR. The number average molecular weight ($M_n$) of the polymer is $5.0{\times}10^4g/mol$ and the glass transition temperature ($T_g$) is $88^{\circ}C$ and its melting point ($T_m$) is $240^{\circ}C$. The cyclic carbonate, styrene carbonate, has been obtained by thermal degradation of the polymer via the unzipping mechanism.

Optimization of the Reaction Conditions for (R)-Phenyl-1,2-ethanediol Preparation by Recombinant Epoxide Hydrolase from Caulobacter crescentus (재조합 Caulobacter crescentus 에폭사이드 가수분해효소를 이용한 광학활성 Diol 제조 조건의 최적화)

  • Lee, Ok-Kyung;Kim, Hee-Sook
    • Microbiology and Biotechnology Letters
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    • v.35 no.4
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    • pp.285-291
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    • 2007
  • Enantioconvergent hydrolysis process for the preparation of chiral diol from racemic epoxides by using the recombinant Caulobacter crescentus epoxide hydrolase (CcEH) in Escherichia coli BL21 (DE3) was optimized. For the optimization, the effects of detergent, temperature and product inhibition on the enantiopurity and the yield of diol were investigated. (R)-phenyl-1,2-ethanediol with 92% enantiomeric excess and 56% yield from 20 mM racemic styrene oxide was obtained by using the recombinant CcEH at the optimal condition of $10^{\circ}C$ and the addition of 2% (w/v) Tween 80. At 50 mM racemic styrene oxide was used as a substrate, (R)-phenyl-1,2-ethanediol was obtained with 87% enantiomeric excess and 77% yield. Racemic phenyl-1,2-ethanediol, (R)-phenyl-1,2-ethanediol and (S)-phenyl-1,2-ethanediol dramatically inhibited the hydrolytic activity of the recombinant CcEH. These results suggested that another EH with the regioselectivity on ${\beta}$-position of (R)-enantiomer and without feedback inhibition by products would be needed as the partner EH of C. crescentus EH.