• Korean Chemical Engineering Research
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• 제46권1호
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• pp.137-141
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• 2008

일반적인 균일계 촉매의 담지 방식 대신 스티렌을 이용하여 촉매를 embedding 시키는 간단한 방법으로 균일계 촉매를 불균일화하여 에틸렌과 알파올레핀의 공중합을 실험하였다. 미량의 스티렌을 $rac-Et[Ind]_2ZrCl_2$ 촉매를 이용하여 중합시켜 embedded $rac-Et[Ind]_2ZrCl_2$ 촉매(이하 embedded 촉매)를 제조하였으며 이를 이용하여 embedding 시키지 않은 homogeneous $rac-Et[Ind]_2ZrCl_2$ 촉매(이하 homogeneous 촉매)를 사용하여 중합한 결과와 비교해 보았다. Embedded 촉매시스템을 사용하여 중합하는 경우, 공단량체의 종류에 상관없이 모든 공단량체 농도에서 촉매의 공중합 활성이 homogeneous 촉매보다 우수하였으며 embedding 과정이 균일계 메탈로센 촉매 활성점의 특성에 영향을 미치지 않았다. 또한 각 촉매시스템으로부터 생성된 고분자의 $T_m$과 NMR 분석 결과로 볼 때, embedded 촉매의 공단량체 삽입 능력은 homogeneous 촉매와 비슷하거나 조금 나은 수준의 결과를 보였으며, embedded 촉매로 중합한 공중합체는 겉보기밀도와 morphology가 우수하여, 스티렌을 이용한 촉매 embedding 방법이 담지 촉매를 이용하여 중합하는 효과를 보일 수 있음을 관찰할 수 있었다.

• 한국대기환경학회지
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• 제20권2호
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• pp.185-193
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• 2004

A catalyst with CuO ceramic filter for simultaneous treatment of dust and HAP was prepared and characterized. Catalytic ceramic filter can not only potentially achieve the substantial savings in energy but provide with effective optimization and integration of process for simultaneous removal of SO$_2$, NO$_{x}$ and particulates from flue gases. Catalytic ceramic filters remove simultaneously particulates on exterior surface of filters and reduce NO to $N_2$ and $H_2O$ by SCR (Selective Catalytic Reduction) process. Preparation of catalyst impregnated ceramic filter with disk shape (Ψ 50) follow the processing of alumino-silicate ceramic filter, support impregnation and catalyst impregnation (copper oxide). Preparation routes of alumino-silicate catalyst carrier suitable for production of catalytic filters practically were studied and developed using the sol-gel and colloidal processing, homogeneous precipitation and impregnation method. Characterization of the catalyst, catalyst carrier catalytic filter materials have been performed the using various techniques such as BET, XRD, TGA, SEM. Combination of the sol-gel and colloidal processing and impregnation method is recommended to prepare catalyst carriers economically for catalytic filter applications.s.

• 대한화학회지
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• 제57권6호
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• pp.703-711
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• 2013

In the present investigation, kinetic studies of oxidation of formic acid with and without catalyst and promoter in aqueous acid media were studied under the pseudo-first order conditions [formic acid]T ${\gg}[Cr(VI)]_T$ at room temperature. In the 1,10-phenanthroline (phen) promoted path, the cationic Cr(VI) phen complex is the main active oxidant species undergoes a nucleophilic attack by the substrate to form a ternary complex which subsequently experiences a redox decomposition through several steps leading to the products $CO_2$ and $H_2$ along with the Cr(III) phen complex. The anionic surfactant (i.e., sodium dodecyl sulfate, SDS) and neutral surfactant (i.e., Triton X-100, TX-100) act as catalyst and the reaction undergo simultaneously in both aqueous and micellar phase with an enhanced rate of oxidation in the micellar phase. Whereas the cationic surfactant (i.e., N-cetyl pyridinium chloride, CPC) acts as an inhibitor restricts the reaction to aqueous phase. The observed net enhancement of rate effects has been explained by considering the hydrophobic and electrostatic interaction between the surfactants and reactants. The neutral surfactant TX-100 has been observed as the suitable micellar catalyst for the phen promoted chromic acid oxidation of formic acid.

• Fibers and Polymers
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• 제1권1호
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• pp.6-11
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• 2000

In the polycondensation reaction of polyethyleneterephthalate(PET), $Sb_2$$O_3$, can react effectively as a catalyst, if physically transformed. $Sb_2$$O_3$ powder is transformed into liquid solution by dissolving in ethylene glycol(EG). Homogeneous catalyst is made by mixing this liquid solution with glycols having different solubility. The efficient reaction of PET polymerization is expected by using homogeneous catalyst. PET was synthesized using homogeneous catalysts of 4 wt.% $Sb_2$$O_3$ solution dissolved in glycol[EG, 2,2-bis(4-(2-hydroxyethoxy)phenol)propane(BHPP), neopentyl glycol(NPO), and 1,3-propandiol(PD)]. PET using EG-BHPP($Sb_2$$O_3$) catalysts shows the highest I.V. within a reaction time of 120 min. In the p-d analysis, PET using EG-BHPP($Sb_2$$O_3$) catalysts has the fastest propagation rate and slowest degradation rate. EG-BHPP($Sb_2$$O_3$) catalysts are more efficient than EG($Sb_2$$O_3$) catalysts and $Sb_2$$O_3$ powder catalysts.

• 동력기계공학회지
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• 제19권4호
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• pp.30-35
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• 2015

The purpose of this study is to identify the low temperature performance and strength characteristics of V-based extruded homogeneous SCR. The extruded catalyst and the coated catalyst showed 50% and 27% of NOx conversion performance respectively at about $210^{\circ}C$ of catalyst temperature, so the extruded SCR was higher in de-NOx performance than the coated SCR especially at a low temperature zone. The compressive strength of the Enhanced Extrusion #1, in which the content of promoters such as silica, clay, glass fiber and binder was optimized, was a 120% improvement compared to the Extrusion#1 catalyst, higher than the coated SCR.

• 한국연소학회지
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• 제5권1호
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• pp.1-6
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• 2000

Surface reaction occurs at a certain surface temperature when a catalyst is heated up in a reactive mixture. If homogeneous ignition does not occur, a steady state is observed because the heat produced by the surface reaction is balanced with the heat loss caused by convection, conduction and radiation. The present paper treats the effects of pressure on the surface temperature at the steady state. Hydrogen and oxygen are used as reactants and nitrogen as an inert gas. A spherical platinum catalyst of 1.5 mm in diameter is sustained in the chamber with two wires of 0.1 mm in diameter. As results, there exists a maximum steady temperature at a certain relative hydrogen concentration which increases with total pressure. At the steady state, it can be approximated that the heat release is estimated by the mass transfer considering the effect of natural convection. The experimental results are explained qualitatively by the approximation.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2000년도 제20회 KOSCO SYMPOSIUM 논문집
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• pp.152-161
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• 2000

The catalytically stabilized combustion of $CH_4$-air mixture on platinum catalyst was investigated numerically using a 2-D boundary layer model with detailed heterogeneous and homogeneous chemistries. The actual surface site density of monolith coated with platinum was decided by the comparison with experimental data. The comparisons were made between results for cases where only heterogeneous chemistry was allowed and both heterogeneous and homogeneous chemistries were allowed. It was found that the homogeneous reaction in the monolith had little effect on the change of temperature profile, methane conversion rate and light off location. The contributions of each reactions related with CO formation were discussed on the surface. The effects of operation conditions such as equivalence ratio, temperature, velocity and pressure at the entrance were studied. In thermal combustor, CO and NOx was produced less than 1 ppm at the exit and the production of $N_{2}O$ was more dominant than that of NO.

• Bulletin of the Korean Chemical Society
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• 제31권10호
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• pp.2973-2979
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• 2010

The newly synthesized homogeneous chiral Co(III) salen complexes were anchored non-covalently on the acidic sites of mesoporous Al-SBA-15. The Bronsted and Lewis acidic sites are attributed to the immobilization of fluorine functionalized chiral salen complexes on the supports. XRD, BET, TEM, FT-IR and ESCA (XPS) analyses were performed to characterize the property of support, and the structure of new homogeneous and heterogeneous chiral Co salen catalyst. The homogeneous and heterogeneous catalysts could be applied in asymmetric ring opening of epichlorohydrine (ECH) by water. They showed very high enantioselectivity and a good yield up to 99% in the catalytic synthesis of optically active products.

• 대한화학회지
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• 제57권4호
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• pp.425-431
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• 2013

Oxidation of glutamic acid is performed in aqueous acid media at $30^{\circ}C$ under the kinetic condition [glutamic acid]$_T{\gg}[Cr(VI)]_T$. Effect of combination of micellar catalyst (SDS, TX-100) and promoter (PA, bpy, phen) has been studied. Among the promoters phen accelerates the reaction most in aqueous media. But the rate acceleration is small in the case. Combination of promoter and catalyst produces much better result. Maximum rate enhancement occurs in presence of the combination of bpy and SDS.

• 한국산학기술학회논문지
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• 제11권4호
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• pp.1348-1353
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• 2010

신디오탁틱 폴리스타이렌의 벌크 중합 시, 반응의 초기단계에서 균일하던 반응혼합물은 반응이 진행됨에 따라 점차 침전된 고형 sPS와 액체 반응생성물로 형성된 슬러리 상태로 변해간다. 반응이 더 진행되면 고형 침전물의 양이 많아지고 반응물이 엉겨 붙는 현상을 적절한 방법으로 해소하면 슬러리 상태에서 젖은 분말 형태 더 나가서는 마른 분말 형태의 반응 생성물을 얻게 된다. 전화율을 높이기 위해 촉매와 조촉매의 양을 늘리는 경우 반응성생물은 어느 순간 한 덩어리가 되어 더 이상의 반응 제어가 불가능해진다. 이 연구에서는 이렇게 덩어리로 응집되는 현상을 막고 고 전화율의 반응이 가능하도록 특별한 방법을 사용하였다. 촉매와 조촉매를 한 번에 투입하지 않고 여러 단계로 나누어 투입하는 경우 반응물의 응집을 막고 전화율을 높게 유지할 수 있었다. 또한 이 방법은 sPS의 분자량을 높이는데도 도움이 되는 것을 알 수 있었다.