• YAKHAK HOEJI
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• v.47 no.5
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• pp.271-275
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• 2003

Easy and efficient synthetic route of novel 4'-C methyl branched carbocyclic nucleosides is described. The installation of alkyl and aryl groups at 4'-position of carbocyclic nucleosides were successfully made via sequential [3,3]-sigmatropic rearrangement and ring-closing metathesis (RCM) starting from simple ketones such as acetol. Adenine and uracil were coupled via Pd(0) catalyzed reaction, followed by desilylation to give novel compounds 13 and 14, respectively.

• Transactions of the Korean hydrogen and new energy society
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• v.28 no.4
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• pp.361-368
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• 2017

Alanate-based materials, which were known to have high hydrogen storage capacity, were synthesized by mechanochemically metathesis reaction of metal chloride and sodium alanate without solvent. XRD patterns of synthesized materials showed that metathesis reaction of cations between metal chloride and sodium alanate was progressed favorably without any solvent. Magnesium alanate showed that 3.2 wt.% of hydrogen was evolved by the thermal decomposition. The addition of a small amount of Ti to the magnesium alanate greatly reduced hydrogen evolution temperature. Also, Ti doped magnesium alanate had a good regeneration property. Both the calcium and lithium-magnesium alanate showed the lower starting temperature of the two step hydrogen evolution and fast kinetics for the hydrogen evolution.

• Bulletin of the Korean Chemical Society
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• v.29 no.10
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• pp.2057-2060
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• 2008

• Bulletin of the Korean Chemical Society
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• v.32 no.1
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• pp.315-318
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• 2011

• YAKHAK HOEJI
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• v.47 no.6
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• pp.417-421
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• 2003

This paper describes a synthetic route to novel 2'-methyl and 4'-hydroxy carbocyclic nucleosides. The methyl group was successfully installed by carbonyl addition reaction of isopropenyl magnesium bromide followed by ring-closing metathesis and the hydroxy group was directly introduced from carbohydrate chiral template "D-lactose".ose".uot;.

• KSBB Journal
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• v.10 no.4
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• pp.449-454
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• 1995

The effects of metathesis for concentrating the tocopherols from soybean and rice-bran scum oils were studied by using the batch reactor under helium atmosphere. The contents of tocopherols in the scum oils decreased consticuously when heated under air atmosphere or when kept in hexane solution above 5 days even at room temperature. The sterols in the scum oils were removed by the mixed solvent method. Metathesis of the sterol-removed scum oils in hexane was performed over Re2O7/Al2O3 and WO3/Al2O3 catalysts, and the concentrate was obtained by distillation in vacuum at $190^{\circ}C$. The effect of metathesis was evaluated as relative ratio of ${\alpha}$-tocopherol in the concentrate to that in scum oil. The maximum ratio for both scum oils was obtained on 12.8%(w/w)$Re_2O_7/Al2O_3$ catalyst which formed effectively the active sites for metathesis by the reaction between the added tetramethyltin and $Re_2O_7$ on the surface of the catalyst. The optimum amount of the catalyst was 0.5g pre l0g scum oil, and the optimum reaction temperature was $25^{\circ}C$ for both scum oils. The metathesis was more effective in rice-bran scum oil than in soybean scum oil. These facts indicated that the tocopherols in the scum oils can be highly concentrated by applying metathesis.

• Bulletin of the Korean Chemical Society
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• v.26 no.2
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• pp.229-230
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• 2005

• Bulletin of the Korean Chemical Society
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• v.25 no.8
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• pp.1280-1282
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• 2004

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.173.3-173.3
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• 2003

In recent years, olefin cross-metathesis (CM) has emerged as a powerful and convenient synthetic technique in organic chemistry; however, as a general synthetic method, CM has been limited by the lack of predictability in product selectivity and stereoselectivity. A number of excellent studies have recently appeared in the literature which have shown that with the correct catalyst and reaction conditions CM can be used to access a variety of di-and trisubstituted olefinic products in moderate to high yield with good E/Z ratios. (omitted)

• Prospectives of Industrial Chemistry
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• v.24 no.2
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• pp.22-30
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• 2021

현재 인류는 플라스틱(plastic) 세상에 살고 있다. 의류, 식품, 주거 생활 곳곳에 플라스틱이 존재하며, 플라스틱이 없는 세상은 상상조차 할 수 없다. 하지만, 플라스틱 사용량 증가에 따른 폐플라스틱의 배출량의 증가는 심각한 환경문제들을 야기하여 생태계뿐만 아니라 인간에게도 위협이 되고 있다. 이를 해결하기 위한 방법으로 단순히 폐플라스틱의 처리에 그치지 않고, 이를 활용하여 새로운 고부가가치의 생성물을 제조하는 플라스틱 업사이클링(plastic upcycling) 시스템이 최근 주목을 받고 있으며, 현재 다양한 형태로 연구개발이 진행되고 있다. 그 중의 한가지로 본 기고문에서는 알칸 교차 복분해(cross alkane metathesis) 반응을 소개한다. 알칸 교차 복분해 반응은 수소화/탈수소화(hydrogenation/dehydrogenation) 반응과 올레핀 복분해(olefin metathesis) 반응으로 이루어져, 탈수소화 반응 후 생성된 이중결합 탄소를 갖는 두 개의 알켄 화합물이 자리바꿈을 통해 새로운 이중 결합을 형성하는 반응이다. 이 촉매반응 과정이 반복되면 저분자화된 새로운 알칸 화합물을 생성되는데, 이는 기존의 플라스틱 처리방식인 열분해 및 촉매 분해 공정보다 낮은 반응온도를 요구한다. 또한 이를 통해 상대적으로 높은 순도의 가솔린 및 디젤을 생성할 수 있기 때문에 폐플라스틱 처리 공정의 새로운 대안기술이 될 수 있다. 본 기고문에서 폐플라스틱 중 가장 큰 비중을 차지하는 폴리에틸렌을 처리하는 대안기술로써 알칸 교차 복분해 반응의 메커니즘과 및 촉매의 역할, 그리고 반응성에 영향을 주는 인자에 대해 기술한다.