• Bulletin of the Korean Chemical Society
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• 제33권8호
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• pp.2748-2752
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• 2012

Cr(III) and Co(III) complexes with acetylacetonate were anchored onto a mesoporous MCM-41 through Schiff condensation. The materials were characterized by XRD, FT-IR, BET, CHN and ICP techniques. Elemental analysis of samples revealed that one C=N bond was formed through Schiff condensation on MCM-41 surface. The catalysts were tested for the alcohol oxidations using t-butyl hydroperoxide (TBHP) and $H_2O_2$ as oxidant. The catalytic experiments were carried out at both room temperature and reflux condition. Various solvents such as dichloromethane, acetonitrile and water were examined in the oxidation of alcohols. Among the different solvents, catalytic activity is found more in acetonitrile. Further, the catalysts were recycled three times in the oxidation of alcohols and no major change in the conversion and selectivity is observed, which shows that the immobilized metal-acetylacetonate complexes are stable under the present reaction conditions.

• 공업화학
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• 제33권6호
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• pp.594-599
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• 2022

본 연구에서는 Pt/V/TiO₂ 촉매 제조 시, V 담지 함량에 따른 NH₃-SCO (selective catalytic oxidation) 반응 활성을 비교하였다. NH₃ 전환율 및 N₂ 선택성을 모두 고려하였을 때, V이 2 wt% 담지된 촉매에서 가장 우수한 성능을 나타내었다. 이에 따라 물리/화학적 특성과 반응활성과의 상관관계를 확인하였을 때, 격자산소종의 증가 및 (V³⁺ + VM⁴⁺) 비율의 증가가 활성인자임을 확인하였다. 또한 가장 우수한 촉매를 이용하여 SO₂ 내구성 실험을 진행하였을 때, 고농도의 SO₂가 주입되더라도 영향이 미미함을 확인하였다.

• Bulletin of the Korean Chemical Society
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• 제30권2호
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• pp.355-362
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• 2009

The chemical modification of multi-wall carbon nanotubes (MWNTs) is an emerging area in material science. In the present study, hydroxyl functionalized oxovanadium(IV) Schiff-base; N,N'-bis(4-hydroxysalicylidene)-ethylene-1, 2-diamineoxovanadium(IV), [VO($(OH)_2$-salen)]; has been covalently anchored on modified MWNTs. The new modified MWNTs ([VO($(OH)_2$-salen)]-MWNTs]) have been characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron (XPS), UV-Vis, Diffuse reflectance (DRS), FT-IR spectroscopy and elemental analysis. The analytical data indicated a composition corresponding to the mononuclear complex of tetradentate Schiff-base ligand. The characterization of the data showed the absence of extraneous complex, retention of MWNTs and covalently anchored on modified MWNTs. Liquid-phase oxidation of cyclohexane with $H_2O_2$ to a mixture of cyclohexanone, cyclohexanol and cyclohexane-1,2-diol in $CH_3$CN have been reported using oxovanadium(IV) Schiff-base complex covalently anchored on modified MWNTs as catalysts. This catalyst is more selective toward cyclohexanol formation.

• 공업화학
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• 제17권5호
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• pp.490-497
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• 2006

$V_{2}O_{5}$/$TiO_{2}$계 선택적촉매환원법(SCR) 촉매는 $SO_{2}$가 존재하는 조건에서 $SO_{2}$의 산화 및 암모니아의 반응에 의해 형성된 황산암모늄염으로 인해 촉매는 비활성화될 수 있다. 본 연구에 의하면, $SO_{2}$에 의한 촉매의 비활성화는 $SO_{2}$의 흡착이후 $SO_{3}$로의 산화 정도에 의존한다. $SO_{2}$의 산화는 배가스 내의 산소 농도에 약하게 영향을 받으며 바나듐 함량에 영향을 받는다. 또한 미반응 암모니아 역시 황산암모늄염 형성의 원인이므로 SCR 반응에 있어서 암모니아 투입비율에 대한 영향을 도출하였다. 황산암모늄염에 의해 비활성화된 촉매가 낮은 SCR 활성을 갖는 이유를 촉매의 기공부피 변화에서 찾을 수 있다. 이러한 황산암모늄염의 분해 반응도출을 위해 TPD (Temperature Programmed Decomposition) 실험이 수행되었다.

• 청정기술
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• 제8권1호
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• pp.53-59
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• 2002

공침-액상산화법으로 $Cu-CeO_2$ 촉매를 제조하여 선택적 산화반응에 대한 활성을 실험적으로 고찰하였다. $Cu-CeO_2$ 촉매는 일산화탄소의 선택적 산화반응에 우수한 활성을 보였으나, 구리의 담지량과 촉매 활성 사이의 일정한 상관관계를 찾을 수 없었다. 또한 구리의 담지량이 증가함에 따라 $CeO_2$의 세공 구조가 변하는 것을 확인할 수 있었으며 이는 Cu와 $CeO_2$가 고용체를 형성하기 때문으로 확인되었다. 촉매 전처리인 환원처리를 통한 Cu와 $CeO_2$의 고용체 형성이 촉매의 일산화탄소의 선택적 산화반응에 대한 활성을 증가시켰다.

• 한국대기환경학회지
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• 제26권3호
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• pp.245-252
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• 2010

For the purpose of evaluating to remove elemental mercury using SCR (Selective Catalytic Reduction) catalysts, the result of the concentration variation of elemental mercury in lab experiment and field measurement was compared. The effect of the elemental mercury oxidation on commercial catalysts was studied in simulated gas. Three species of SCR catalyst, $V_2O_5-TiO_2$ type, were selected. The elemental mercury reduced 30% without HCl gas in SCR operating condition. But the width of reduction increased 60% at 20 ppm HCl gas. According to the result of field measurement, reduction rate of elemental mercury at SCR outlet showed 60%. The total mercury concentration decreased about 20%. The results were similar to the lab test. The results of chemical analysis of test sample showed increase of mercury concentration but surface change was not observed.

• Journal of Korean Society for Atmospheric Environment
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• 제18권E1호
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• pp.29-36
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• 2002

The selective catalytic reduction (SCR) reaction of promoter catalysts was investigated in this study. A pure anatase type of TiO$_2$ was used as support. Activation measurement of prepared catalysts was practiced on a fixed reactor packing by the glass bead after filling up catalysts in 1/4 inch stainless tube. The reaction temperature was measured by K-type thermocouple and catalyst was heated by electric furnace. The standard compositions of the simulated flue gas mixture in this study were as follows: NO 1,780ppm, NH$_3$1,780ppm, $O_2$1% and $N_2$ as balance gas. In this study, gas analyzer was used to measure the outgassing gas. Catalyst bed was handled for 1hr at 45$0^{\circ}C$, and the reactivity of the various catalyst was determined in a wide temperature range. Conversion of NH$_3$/NO ratio and of $O_2$ concentration was practiced at 1,1.5 and 2, respectively. The respective space velocity were as follows . 10,000, 15,000 and 17,000 hr-1. It was found that the maximum conversion temperature range was in a 5$0^{\circ}C$. It was also found toi be very sensitive at space velocity, $O_2$ concentration, and NH$_3$/NO ratio. We also noticed that the maximum conversion temperature of (W, Mo, Sn) -V$_2$O$_{5}$/TiO$_2$ catalysts was broad. Specially WO$_3$-V$_2$O$_{5}$TiO$_2$2 catalyst appeared nearly 100% conversion at not only above 30$0^{\circ}C$ ut also below 25$0^{\circ}C$. At over 30$0^{\circ}C$, NH$_3$ oxidation decreased with decrease of surface excess oxygen. In addition, WO$_3$-V$_2$O$_{5}$TiO$_2$ catalyst did not appear to affect space velocity, $O_2$ concentration, and NH$_3$/NO ratio.ratio.

• 한국자동차공학회논문집
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• 제17권1호
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• pp.154-161
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• 2009

This study is a part of project of urea-SCR system development for an in-use medium duty diesel engine. This study shows the effect of ammonia oxidation catalyst and SCR volume on $NO_X$ reduction performance. When AOC(Ammonia Oxidation Catalyst) is not used, the urea injection should be controlled accurately to prevent $NH_3$ slip. However, it is found that the accurate $NH_3$ slip control is not easy without AOC in real engine operating conditions, because $NH_3$ and $NO_X$ reaction characteristics change with many factors such as exhaust gas temperature and $NH_3$ absorbance on SCR. SCR volume is also one of important design parameters. This study shows that $NO_X$ reduction efficiency increases with increase of SCR volume especially at high space velocity and low exhaust gas temperature conditions. Additionally, this paper shows the emissions of EURO-2 medium duty diesel engine can be improved to the level of EURO-5 with a DPF and urea-SCR system.

• 공업화학
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• 제33권1호
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• pp.103-108
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• 2022

본 연구에서는 아이소소바이드(1,4:3,6-dianhydro-D-glucitol)로부터 그에 상응하는 아이소소바이드-디케톤[2,6-dioxabicyclo(3,3,0)octan-4,8-one]으로의 높은 선택적 전환을 통한 효율적인 루테늄/템포/나이트레이트 촉매 시스템 개발에 대해 보고한다. 미래의 제조 공정에서의 중요한 플랫폼 화합물 중 하나는 아이소소바이드이다. 오랜 시간 동안, TEMPO(2,2,6,6-tetramethylpiperidine-N-oxyl)는 알코올을 카보닐 화합물로 변환하는데 사용되어 왔다. 본 화학 반응에서는 산소 1atm 압력하에, Ru (10 mol%), TEMPO (5 mol%), 질산나트륨(0.03 mmol) 그리고 아이소소바이드(0.5 mmol)를 용매 아세트산(3 ml)을 사용하여 최적화되었다. 이러한 촉매 시스템은 이중 산화 촉매 반응 메커니즘에 대한 가능성뿐만 아니라, 생성물에 대한 원하는 반응물의 높은 선택성(> 97%)과 수율(87%)을 보여주었다.

• 한국자동차공학회논문집
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• 제24권2호
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• pp.152-160
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• 2016

The market demand for diesel engine tends to increase in general passenger cars as well as commercial vehicles because of its advantages. However, to meet the vehicle emissions regulation which will be more stringent in the future, it is necessary to plurally apply all after-treatment technologies such as diesel oxidation catalyst (DOC), catalyzed diesel particulate filter (CDPF), lean NOx trap (LNT) and selective catalytic reduction (SCR), and so on. Accordingly, the exhaust after-treatment system for diesel vehicle requires the technology of minimizing the numbers of catalysts by integrating every individual catalysts. The purposes of this study is to develop hybrid exhaust after-treatment device system which simultaneously uses LNT/DPF and SCR/DPF catalyst concurrently reducing NOx and particulate matter (PM). As the results, the hybrid system with $NH_3$ generated at LNT/DPF working as a reducing agent of SCR/DPF catalyst, improving NOx conversion rate, was found to be more excellent in de-NOx performance than that in LNT/DPF alone system.