• 제목/요약/키워드: Epoxidation.

검색결과 103건 처리시간 0.024초

Photocatalytic Epoxidation of Olefins Using Molecular O2 by TiO2 Incorporated in Hydrophobic Y Zeolite

  • Kuwahara, Yasutaka;Magatani, Yasuhiro;Yamashita, Hiromi
    • Rapid Communication in Photoscience
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    • 제4권1호
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    • pp.19-21
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    • 2015
  • Zeolite is an ideal host material for encapsulating nano-size metal catalyst species because of its defined microporous structure, prominent adsorption/condensation properties, high surface area, chemical/thermal stability, and transparency to light. In this study, $TiO_2$ photocatalyst was incorporated in highly hydrophobic Y zeolite and its photocatalytic activity was examined in the photocatalytic oxidation of olefins under UV-light irradiation using molecular oxygen as an oxygen source. $TiO_2$ nanoparticles incorporated in hydrophobic Y zeolite exhibited a markedly enhanced photocatalytic activity compared with bare $TiO_2$ owing to its excellent affinity toward organic moieties, which facilitates the mass transfer of organic substrates and allows them to efficiently access to the neighboring active $TiO_2$ surface.

Synthesis of Mesoporous TS-1 for Catalytic Oxidative Desulfurization

  • Park, Chul-Woo;Kim, Tae-Kyung;Ahn, Wha-Seung
    • Bulletin of the Korean Chemical Society
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    • 제30권8호
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    • pp.1778-1782
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    • 2009
  • Mesoporous TS-1 catalysts were prepared via a nanocasting route using two different carbon template sources of CMK-3 and commercial carbon black. Products were characterized by XRD, UV-Vis spectroscopy, SEM, TEM, and $N_2$ adsorption- desorption measurement. The catalytic performances of the samples for allylchloride epoxidation and oxidative desulfurization of the representative refractory sulfur compounds, dibenzothiophene and 4,6-dimethyldibenzothiophene, were compared against those of conventional TS-1. Whilst the allychloride epoxidation activity for the mesoporus TS-1 samples were similar, mesoporous TS-1 exhibited significantly higher catalytic activities than conventional TS-1 in oxidative desulfurization.

P123-Templated Co3O4/Al2O3 Mesoporous Mixed Oxides for Epoxidation of Styrene

  • Jung, Mie-Won;Kim, Young-Sil
    • 한국재료학회지
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    • 제22권6호
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    • pp.316-320
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    • 2012
  • $Co_3O_4$, $Al_2O_3$ and $Co_3O_4$/$Al_2O_3$ mesoporous powders were prepared by a sol-gel method with starting matierals of aluminum isopropoxide and cobalt (II) nitrate. A P123 template is employed as an active organic additive for improving the specific surface area of the mixed oxide by forming surfactant micelles. A transition metal cobalt oxide supported on alumina with and without P123 was tested to find the most active and selective conditions as a heterogeneous catalyst in the reaction of styrene epoxidation. A bBlock copolymer-P123 template was added to the staring materials to control physical and chemical properties. The properties of $Co_3O_4$/$Al_2O_3$ powder with and without P123 were characterized using an X-ray diffractometer (XRD), a Field-Emission Scanning Electron Microscope (FE-SEM), a Bruner-Emmertt-Teller (BET) surface analyzer, and $^{27}Al$ MAS NMR spectroscopy. Powders with and without P123 were compared in catalytic tests. The catalytic activity and selectivity were monitored by GC/MS, $^1H$, and $^{13}C$-NMR spectroscopy. The performance for the reaction of epoxidation of styrene was observed to be in the following order: [$Co_3O_4$/$Al_2O_3$ with P123-1173 K > $Co_3O_4$/$Al_2O_3$ with P123-973 K > $Co_3O_4$-973 K>$Co_3O_4$/$Al_2O_3$-973 K > $Co_3O_4$/$Al_2O_3$ with P123-1473 K > $Al_2O_3$-973 K]. The existence of ${\gamma}$-alumina and the nature of the surface morphology are related to catalytic activity.

Mo/SiO2 촉매상에서 t-Butyl hydroperoxide에 의한 염화알릴의 에폭시화반응에 관한 속도론적 연구 (Kinetic Study on the Epoxidation of Allyl Chloride by t-Butyl Hydroperoxide over Mo/SiO2 Catalyst)

  • 김성우;박대원;정종식;박대철
    • 공업화학
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    • 제3권4호
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    • pp.649-656
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    • 1992
  • t-Butyl hydroperoxide(TBHP)에 의한 염화알릴의 에폭시화에 의해서 에피클로로히드린을 합성하는데 실리카에 담지된 몰리브데늄 촉매를 사용하였다. 속도론적 연구는 회분 반응기를 사용하여 $60-80^{\circ}C$, 10기압에서 TBHP/염화알릴의 농도비를 0.01-0.1의 범위내에서 수행하였다. t-butyl alcohol(TBA)에 의해서 염화알릴의 에폭시화 반응이 억제되었고, 반응속도는 Michaelis-Menten 형태의 속도식으로 표현할 수 있었다. 반응기구는 TBHP와 TBA의 가역흡착과 $Mo/SiO_2$에 흡착된 TBHP와 염화알릴의 표면반응으로 설명할 수 있었다.

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