• KSBB Journal
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• v.11 no.3
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• pp.263-269
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• 1996

Anticancer agent taxol was synthesized from baccatin III which was extracted from cell cultures of European yew, Taxus baccata Pendula. Callus and suspension cultures of T. baccata Pendula showed the formation baccatin III. The content of baccatin III in cell cultures reached 0.015% (w/w) on dry weight basis. The semisynthetic approaches were made with baccatin III and taxol side chain. To prepare taxol side chain, (-)-N-((S)-2-hydroxy-1-phenylethyl) benzamide was synthesized first from (S)-(+)-phenylglycine. Then (-)-N-((IS,2S)-2-hydroxy-1-phenyl-3-butenyl) benzamide was synthesized with vinyl magnesium bromide. The synthesis of (2R, 3S)-(-)-2-(1-ethoxyethoxy)-3-phenyl-3-(phenylmethanamido) propanoic acid with RuCl3, catalyst was the final step to prepare taxol side chain. The semisynthetic reactions yielded 0.0002% taxol, 0.0005% 7-epi-10-deacetyltaxol, and unidentified taxanes on dry weight basis. It is suggested that the semisynthesis of taxol from baccatin III could be an alternative source of taxol and related taxanes.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.157.1-157.1
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• 2011

선택적 CO 산화반응(PrOx)에 사용되는 촉매 중 Pt, Ru, Rh 등의 귀금속 계 촉매들은 비귀금속 계 촉매에 비해 활성이 좋은 반면 가격이 비싸다는 경제적인 제한점이 있다. 따라서 소량의 귀금속을 사용하여 높은 활성의 촉매를 제조하고자 활성금속의 고분산 담지 방법에 대한 연구가 이루어지고 있다. 본 연구에서는 담체인 ${\gamma}-Al_2O_3$ 표면에 활성금속인 Pt의 고분산 담지를 위해 증착-침전법(Deposition-precipitation)을 적용하였으며 용액의 pH 변화에 따른 Pt 금속 입자의 분산도에 대한 영향을 살펴보았다. Pt의 함량은 1wt%로 고정하였고 침전제로 NaOH를 사용하여 용액의 pH를 pH 7.5 ~ 10.5로 변화시켰다. 제조된 촉매는 세척 후 $400^{\circ}C$, 3시간 소성 하였다. 제조된 1wt% Pt/$Al_2O_3$ 촉매의 특성분석을 위해 BET, TPR, CO-chemisorption을 수행하였다. PrOx 반응 실험은 GHSV=60,000 $ml/g_{cat}{\cdot}h$, $T=100{\sim}200^{\circ}C$, ${\lambda}$=4 조건에서 수행되었으며 반응 전에 촉매는 $400^{\circ}C$, 3시간 환원 후 사용하였다. 촉매의 특성분석과 PrOx 반응 실험 결과를 통해 촉매가 담체 위에 고분산 되는 최적의 pH를 확인할 수 있었으며, 기존의 함침법으로 제조된 촉매와 성능 비교를 통해 제조방법에 따른 영향을 살펴보았다.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.317.2-317.2
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• 2013

Ultrathin oxide encapsulated metal-oxide hybrid nanocatalysts have been fabricated by a soft chemical and facile route. First, SiO2 nanoparticles of 25~30 nm size have been synthesized by modified Stobber's method followed by amine functionalization. Metal nanoparticles (Ru, Rh, Pt) capped with polymer/citrate have been deposited on functionalized SiO2 and finally an ultrathin layer of TiO2 coated on surface which prevents sintering and provides high thermal stability while maximizing the metal-oxide interface for higher catalytic activity. TEM studies confirmed that 2.5 nm sized metal nanoparticles are well dispersed and distributed throughout the surface of 25 nm SiO2 nanoparticles with a 3-4 nm TiO2 ultrathin layer. The metal nanoparticles are still well exposed to outer surface, being enabled for surface characterization and catalytic activity. Even after calcination at $600^{\circ}C$, the structure and morphology of hybrid nanocatalysts remain intact confirm the high thermal stability. XPS spectra of hybrid nanocatalyst suggest the metallic states as well as their corresponding oxide states. The catalytic activity has been evaluated for high temperature CO oxidation reaction as well as photocatalytic H2 generation under solar simulation. The design of hybrid structure, high thermal stability, and better exposure of metal active sites are the key parameters for the high catalytic activity. The maximization of metal-TiO2 interface interaction has the great role in photocatalytic H2 production.

• Clean Technology
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• v.28 no.3
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• pp.232-237
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• 2022

Biorefineries, in which renewable resources are utilized, are an eco-friendly alternative based on biomass feedstocks. Alginic acid, a major component of brown algae, which is a type of marine biomass, is widely used in various industries and can be converted into value-added chemicals such as sugars, sugar alcohols, furans, and organic acids via catalytic hydrothermal decomposition under certain conditions. In this study, ruthenium-supported activated carbon and magnesium oxide were mixed and applied to the depolymerization of alginic acid in a batch reactor. The addition of magnesium oxide as a basic promoter had a strong influence on product distribution. In this heterogeneous catalytic system, the separation and purification processes are also simplified. After the reaction, low molecular weight alcohols and organic acids with 5 or fewer carbons were produced. Specifically, under the optimal reaction conditions of 30 mL of 1 wt% alginic acid aqueous solution, 100 mg of ruthenium-supported activated carbon, 100 mg of magnesium oxide, 210 ℃ of reaction temperature, and 1 h of reaction time, total carbon yields of 29.8% for alcohols and 43.8% for a liquid product were obtained. Hence, it is suggested that this catalytic system results in the enhanced hydrogenolysis of alginic acid to value-added chemicals.