• Bulletin of the Korean Chemical Society
• /
• 제33권4호
• /
• pp.1279-1284
• /
• 2012

Silica supported $Cs_{2.5}H_{0.5}PMo_{12}O_{40}$ catalyst was prepared through sol-gel method with ethyl silicate-40 as silicon resource and characterized by X-ray diffraction, infrared spectroscopy, scanning electron microscopy, nitrogen adsorption-desorption and potentiometric titration methods. The $Cs_{2.5}H_{0.5}PMo_{12}O_{40}$ particles with Keggin-type structure well dispersed on the surface of silica, and the catalyst exhibited high surface area and acidity. The catalytic performance of the catalysts for benzene liquid-phase nitration was examined with 65% nitric acid as nitrating agent, and the effects of various parameters were tested, which including temperature, time and amount of catalyst, reactants ratio, especially the recycle of catalyst was emphasized. Benzene was effectively nitrated to mononitro-benzene with high conversion (95%) in optimized conditions. Most importantly, the supported catalyst was proved has excellent stability in the nitration progress, and there were no any other organic solvent and sulfuric acid were used in the reaction system, so the liquid-phase nitration of benzene that we developed was an eco-friendly and attractive alternative for the commercial technology.

• 공업화학
• /
• 제3권1호
• /
• pp.7-17
• /
• 1992

100% $H_2SO_4$($H_0=-11.93$)보다 더 강한 산을 초강산이라고 한다. 그러나 고체초강산 촉매는 액체초강산촉매에 비하여 촉매와 반응생성물의 분리의 용이성, 촉매의 반복사용가능, 촉매의 재생가능 등과 같은 많은 이점을 가지고 있다. 이 총설에서는 고체초강산 촉매의 종류, 제법, 그리고 화학반응에서의 응용에 대하여 소개한다.

• 한국추진공학회지
• /
• 제6권1호
• /
• pp.30-38
• /
• 2002

복합재 연소관에 기계적 물성을 향상시킨 추진제를 충전한 모타와 복합재 연소관에 기존의 내탄도 성능을 어느 정도 유지하며 연소속도의 조절로 추진제의 둔감화를 시도한 추진제를 충전한 로켓모타에 대하여 탄환충격시험을 실시하여 그 반응을 비교·분석하였다.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2009년도 추계학술대회 논문집
• /
• pp.218-221
• /
• 2009

Solid oxide fuel cells (SOFCs), as high-temperature fuel cells, have various advantages. In some merits of SOFCs, high temperature operation can lead to the capability for internal reforming, providing fuel flexibility. SOFCs can directly use CH4 and CO as fuels with sufficient steam feeds. However, hydrocarbons heavier than CH4, such as ethylene, ethane, and propane, induce carbon deposition on the Ni-based anodes of SOFCs. In the case of the ethylene steam reforming reaction on a Ni-based catalyst, the rate of carbon deposition is faster than among other hydrocarbons, even aromatics. In the reformates of heavy hydrocarbons (diesel, gasoline, kerosene and JP-8), the concentration of ethylene is usually higher than other low hydrocarbons such as methane, propane and butane. It is importatnt that ethylene in the reformate is removed for stlable operation of SOFCs. A new methodology, termed post-reforming was introduced for removing low hydrocarbons from the reformate gas stream. In this work, activity tests of some post-reforming catalysts, such as CGO-Ru, CGO-Ni, and CGO-Pt, are investigated. CGO-Pt catalyst is not good for removing ethylene due to low conversion of ethylene and low selectivity of ethylene dehydrogenation. The other hand, CGO-Ru and CGO-Ni catalysts show good ethylene conversion, and CGO-Ni catalyst shows the best reaction selectivity of ethylene dehydrogenation.

• 한국군사과학기술학회지
• /
• 제22권1호
• /
• pp.35-41
• /
• 2019

Ferrocene and ferrocene derivatives have been widely used as a burning rate catalyst for composite solid propellants. However, its tendency to migrate through the propellant grain and to crystallize at the surface changes the composition of propellant which results in unpredictable burning rate. To overcome the weakness of ferrocene catalyst, we designed a polymer containing ferrocene, poly(glycidyl azide-co-glycidyl ferrocenyl ether) (GAFP). GAFPs were synthesized from poly(epichlorohydrin-co-glycidyl ferrocenyl ether) (PEGF) which has ferrocenyl ethers in its pendant groups. The structures of GAFPs were confirmed by FT-IR, $^1H$ and $^{13}C$ NMR spectral analyses. Thermal properties of the GAFPs were evaluated using differential scanning calorimeter (DSC). As the contents of ferrocene increased, the glass transition temperature ($T_g$) of the GAFPs shifted to a higher temperature, and the decomposition temperature ($T_d$) decreased because the ferrocene worked as a burning rate catalyst.

• 한국추진공학회지
• /
• 제24권5호
• /
• pp.84-90
• /
• 2020

본 논문은 이종추진제(1차 추진제/2차 추진제) 접착에 필요한 코팅제에 대해 기술하였다. 코팅제는 유기용매, 고분자 경화제, 경화촉매로 구성되어 있다. 경화촉매인 FeAA를 0.14 wt% 이상 적용한 코팅제는 2차 추진제 경화 직후 시험한 결과 접착계면이 아닌 추진제가 파단되는 결과를 확인하였으며, 0.10 wt% 이하에서는 접착계면이 파단되었다. 경화촉매는 2차 추진제 경화 직후 접착계면이 파단되는 결과를 확인하였다. 또한 TPB 경화촉매를 적용한 코팅제의 경우 시간이 경과함에 따라 1차 추진제와 2차 추진제간의 접착력이 증가하는 결과를 확인하였다.

• 한국자동차공학회논문집
• /
• 제22권5호
• /
• pp.73-83
• /
• 2014

CFD(computational fluid dynamics) model is developed to simulate direct injection of ammonia gas phase from ammonia transporting materials into the SCR catalyst in the exhaust pipe of the engine with solid SCR. Configurations of one-hole and four-hole nozzle, circumferential type, porous tube type, and the effect of mixer configurations which commonly used in liquid injection of AdBlue are considered for complex geometries. Mal-distribution index related to concentration of ammonia gas, flow uniformity index related to velocity distribution, and pressure drop related to flow resistance are compared for different configurations of complex geometries at the front section of SCR catalyst. These results are used to design the injection system of ammonia gas phase for solid SCR of target vehicle.

• Korean Chemical Engineering Research
• /
• 제54권1호
• /
• pp.64-69
• /
• 2016

바이오디젤 공정에서 비균일상 촉매는 생성물의 회수를 쉽게 하며 촉매를 재사용하는 장점이 있기 때문에 최근 연구가 활발히 진행되고 있다. 본 연구에서는 $K_2CO_3/{\gamma}-Al_2O_3$ 촉매를 이용한 바이오디젤 생성 반응에서 촉매의 소성온도가 반응활성에 미치는 영향을 살펴보았다. 소성온도가 $600^{\circ}C$까지 높아짐에 따라 촉매의 활성이 높아졌으며, 그 이상의 온도에서는 촉매의 활성이 급격히 감소하여 소성온도가 촉매의 활성에 매우 중요한 영향을 주는 것을 확인하였다. 고온에서 이와 같은 활성감소는 Al-O-K와 $Al-O_2-K$인 활성자리의 감소가 원인이었던 것으로 추정되었다.

• 한국추진공학회지
• /
• 제24권6호
• /
• pp.10-15
• /
• 2020

본 연구는 동일한 제조법을 가지는 연소촉매 FeOOH와 Fe₂O₃를 제조하여 고체추진제에 적용 후 기계적 물성 및 연소 특성의 변화에 관한 내용이다. 동일한 제조방법을 가지는 FeOOH와 Fe₂O₃를 만들기 위하여 FeOOH를 200, 300, 400, 500℃에서 2시간 동안 소성시킨 후 XRD 결과를 확인하였다. 또한, 제조된 촉매를 고체추진제에 적용 후 기계적 물성 및 연소 특성의 변화를 나타내었다. XRD 결과상으로 FeOOH는 200~300℃사이에서 Geothite에서 Hematite로 결정상이 변화하는 것을 확인하였다. 추진제의 응력은 연소촉매의 소성온도가 높아짐에 따라 변화가 거의 없지만 연신율은 소성을 진행한 촉매를 적용 시 증가하였다. 연소속도는 소성을 하지 않은 FeOOH가 다른 촉매에 비해 약 3~5% 빠르다는 것을 확인하였다.

• 한국세라믹학회지
• /
• 제55권1호
• /
• pp.50-54
• /
• 2018

This study investigated the long-term durability of catalyst(Pd or Fe)-infiltrated solid oxide cells for $CO_2$/steam co-electrolysis. Fuel-electrode supported solid oxide cells with dimensions of $5{\times}5cm^2$ were fabricated, and palladium or iron was subsequently introduced via wet infiltration (as a form of PdO or FeO solution). The metallic catalysts were employed in the fuel-electrode to promote $CO_2$ reduction via reverse water gas shift reactions. The metal-precursor particles were well-dispersed on the fuel-electrode substrate, which formed a bimetallic alloy with Ni embedded on the substrate during high-temperature reduction processes. These planar cells were tested using a mixture of $H_2O$ and $CO_2$ to measure the electrochemical and gas-production stabilities during 350 h of co-electrolysis operations. The results confirmed that compared to the Fe-infiltrated cell, the Pd-infiltrated cell had higher stabilities for both electrochemical reactions and gas-production given its resistance to carbon deposition.