• Polymer Science and Technology
• /
• v.5 no.3
• /
• pp.236-253
• /
• 1994

양이온형 $d^0\;Cp_2M(R)(L)^+$ 착물과 무염기 $Cp_2M(R)^+$ 착물은 $Cp_2M(R)_2$화합물로부터 쉽게 합성할 수 있다. 이들 친전자성 착물에서는 여러가지 리간드 교환반응, 삽입반응, ${\beta}$-H 제거반응 및 ${\sigma}$-결합 복분해반응이 일어날 수 있다. 일반적으로 $Cp2M(R)(L)^+$ 착물은 불포화도와 전하가 크기때문에 중성의 $Cp_2M(R)(X)$나 $Cp_2M(R)_2$보다 반응성이 크며 $d^0\;{Cp_2}^*M(R)^+$ (M=제 3족과 란탄계) 착물과 여러가지 반응에서 유사한 거동을 보인다. $Cp_2MX_2$를 기초로하여 합성된 Ziegler-Natta 촉매에 의한 올레핀 중합에서 활성점이 $Cp_2M(R)^+$ 양이온이라는 여러가지 직접적인 증거가 발표되었다. 분리가능한 $Cp_2M(R)(L)^+$ 착물은 올레핀중합에서 높은 활성을 보이며, 유기합성의 관점에서 흥미있는 C-C 재조합반응과 같은 다른 여러가지 반응이 일어날 수 있는 기회를 제공한다.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.16 no.2
• /
• pp.150-157
• /
• 2004

Carbon dioxide ($CO_2$, R-744) has become a very popular issue in application to refrigeration and air conditioning systems as a natural refrigerant. An experimental study has been carried out to investigate miscibility and the vapor pressure of refrigerant R-744 in the presence of lubricant oil. This is of particular interest in the selection of the lubricant oil for the compressor of a refrigeration system or an air conditioning system using the refrigerant R-744. The experimental set-up consists of the equilibrium cell, measuring devices, the vacuum pump, the constant temperature bath and relevant connecting pipes made of stainless steel. Five lubricant oils, such as mineral oil (Naphthenic), AB (Alkyl Benzene) oil, PAO (Poly Alpha Olefin) oil, PAG (Poly Alkylene Glycol) oil and POE (Polyol Ester) oil are considered in the present study. Test runs were conducted with the oil concentration range from 5 to 50 wt％, and the temperature range from -10 to 1$0^{\circ}C$ with 2$^{\circ}C$ intervals. The miscibility results are visualized and correlated with the vapor pressure for the individual test components.

• Bulletin of the Korean Chemical Society
• /
• v.23 no.4
• /
• pp.563-566
• /
• 2002

Copper complexes have been directly incorporated into cellulose acetate (CA) and the resulting light blue colored homogeneous films of 5-20 wt.% copper acetate complex concentrations are found to be thermally stable up to 200 $^{\circ}C$. The reaction chem istry of Cu in CA has been investigated by reacting them with small gas molecules such as CO, H2, D2, O2, NO, and olefins in the temperature range of 25-160 $^{\circ}C$, and various Cu-hydride, -carbonyl, -nitrosyl, and olefin species coordinated to Cu sites in CA are characterized by IR and UV/Vis spectroscopic study. The reduction of Cu(II) complexes by reacting with H2 gas at the described conditions results in the formation of Cu2O and copper metal nanoparticles in CA, and their sizes in 30-120 nm range are found to be controlled by adjusting metal complex concentration in CA and/or the reduction reaction conditions. These small copper metal particles show various catalytic reactivity in hydrogenation of olefins and CH3CN; CO oxidation; and NO reduction reactions under relatively mild conditions.

• Polymer Science and Technology
• /
• v.17 no.2
• /
• pp.226-235
• /
• 2006

• Macromolecular Research
• /
• v.16 no.8
• /
• pp.676-681
• /
• 2008

The $\pi$-complex membranes of poly(styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS) of two silver salts of $AgBF_4$ and $AgCF_3SO_3$ were prepared and tested for the separation of the propylene/propane mixtures. The Fourier-transform infrared (FT-IR) spectra of these complexes showed that the silver salts were dissolved in SEBS up to a silver mole fraction of 0.14, due to $\pi$-complexation between the aromatic C=C bonds of styrene blocks and silver ions. Above this solubility limit, ion pairs and high-order ionic aggregates began to form, so that silver salts were distributed unselectively in both the EB and PS blocks. The domain size of the PS blocks was enlarged up to this critical concentration with increasing silver concentration without structural transitions, as confirmed by small angle x-ray scattering (SAXS). These structural properties of the SEBS/silver salt complexes may explain the lower separation properties for propylene/propane mixtures compared to poly(styrene-b-butadiene-b-styrene)(SBS)/silver salt complex membranes.

• Bulletin of the Korean Chemical Society
• /
• v.23 no.12
• /
• pp.1702-1708
• /
• 2002

The synthesis and catalytic application of a new class of a new class of planar chiral ferrocenes, 1,2-ferrocenediylazaphosphinines (1 and 2) are described. They are powerful ligands for the copper(I)-catalyzed asymmetric cyclopropanation of a range of alkenes with diazo esters to exhibit an exceptionally high degree of diastereoselectivity(~100% de) in favor of trans isomers, regardless the structure of the olefins and the diazo compounds. Comparative studies between 1 and 2 reveal that the former works better in terms of diastereocontrol. In contrast, however, enantioselectivity is low with both 1 and 2 as a whole although, in certain cases with a proper combination of the olefin and the diazo ester, high optical yields (up to 100% ee) can be achieved. Other reaction parameters such as the reaction temperature and the structure of the ligand do exhibit some influence, although infinitestimal, on both chemical and optical yields.

• Microbiology and Biotechnology Letters
• /
• v.22 no.3
• /
• pp.271-276
• /
• 1994

The strain S4-14 which produced alkaline lipase and had resistance against linear alkylbenzene sulfonate was isolated from soil or water samples. The isolated strain S4-14 was identified a species belong to Pseudomonas. Alkalin lipase secreted by Pseudomonas sp. S4-14 was purified by ammonium sulfate precipitation procedure follwed by DEAE-Cellulose, DEAE-Sepharose and gel filtration chromatohraphies with 995.15 U/mg protein and 16.1% yield. The molecular weight of the enzyme was estimated to be 65,000 dalton by SDS-PAGE. The optimum pH and temperature of the purified enzyme was 10.5 and 45$\circ $C, respectively. The emzyme was stable at 45$\circ $C for 1 hr and in a pH range from 8.0 to 12.0 for 24 hr at 4$\circ $C. The activity of lipase was enhanced by Ca$^{2+}$ while inhibited strongly by Pb$^{2+}$, Zn$^{2+}$ or Fe$^{3+}$. The activity of lipase was inactivated about 50~60% in the presence of 50 mg/l linear alkylbenzene sulfonate, $\alpha $-olefin sulfonate, alcohol ethoxylate or perborate.

• 한국신재생에너지학회:학술대회논문집
• /
• 2006.06a
• /
• pp.523-526
• /
• 2006

The target of this work was the process development of demonstration plant to produce the high quailty alternative fuel oil by the pyrolysis of mixed plastic waste. In the first step of research, the bench-scale units of 70t/y and the pi lot plant of 360 t/v had been developed. Main research contents in this step were the process performance test of pilot plant ot 360ton/year and the development of demonstration plant of 3 000 t/y which was constructed at Korea R & D Company in Kimjae City. The process performance of pilot plant of 360 t/v showed components in PONA group appeared at between that of commercial gasoline and kerosene. On the other hand, HO product was mainly paraffin and olefin components and also appeared at upper temperature distribution range than commercial diesel. Gas product showed a high fraction of $C_3\;and\;C_4$ product like LPG composition, but also a high fraction of $CO_2$ and CO by probably a little leak of process.

• Applied Chemistry for Engineering
• /
• v.27 no.2
• /
• pp.128-134
• /
• 2016

Due to the great development made in converting the shale gas into the more valuable products, research and commercialization for production technology of olefins like propylene, butenes, butadiene from light alkanes have been intensively investigated. Especially the technology using oxygen like oxidative dehydrogenation or selective hydrogen combustion to overcome thermodynamic limit of direct dehydrogenation conversion has been extensively studied and some cases of applying this technology to the plant scale was reported. In this review, we have categorized the technology into two parts; gas phase oxygen utilization technology and lattice oxygen utilization technology. The trends, results and future direction of the technology are discussed.

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