• 한국응용과학기술학회지
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• 제26권4호
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• pp.415-421
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• 2009

Esterification reaction between succinic acid[SA] and 1,4-butanediol [BD} was kinetically investigated in the presence of organic metal catalysts (alkyl-silver oxide(ASO),CAT 100E) at $150{\sim}190^{\circ}C$. The reaction rates measured by the amount of distilled water from the reaction vessel. The esterification reaction was carried out under the first order kinetics with respect to the concentration of reactants and catalyst, respectively. The overall reaction order was 2nd. From the examination of relationship between apparent reaction rate constants and reciprocal absolute temperature, the activation energy has been calculate as 146.70 kJ/mol with ASO catalyst and 43.04 kJ/mol with CAT 100E catalyst.

• 대한방사성의약품학회지
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• 제3권2호
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• pp.116-121
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• 2017

To overcome the low reactivity and solubility of alkali metal fluorides (MFs), various types of phase transfer catalysts (PTCs) have been developed over the last decades. However, since the fluoride activated by such PTC sometimes has a strong basicity, it may cause various side reactions such as elimination reaction or hydroxylation reaction in the nucleophilic fluorination reaction. Also, they may cause separation problems in the compound purification process. In recent advanced study, various PTCs have been developed to solve these problem of conventional catalyst. In this review, we would like to introduce three kinds of novel multifunctional organic catalysts such as bis-tert-alcohol-functionalized crown-6-calix[4]arene (BACCA), easy separable pyrene-tagged ionic liquid (PIL) by reduced graphene oxide (rGO), and tri-tert-butanolamine organic catalyst.

• 한국대기환경학회지
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• 제22권4호
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• pp.431-439
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• 2006

Catalytic oxidation of benzene, toluene and xylene (BTX) using regenerated metal oxide catalysts (ZnO-CuO, NiO, $Fe_2O_3$, ZnO, CrO) were investigated in a fixed bed flow reactor to evaluate their feasibility for the purpose of removing volatile organic compounds (VOCs). Four kinds of pre-treatment methods such as gas (air and hydrogen), acid aqueous solution, alkali aqueous solution and cleaning agent were used to find out the optimal regeneration conditions. The physico-chemical properties of the used and regenerated catalysts were characterized by BET and TPR (Temperature Programmed Reduction). The used catalysts showed high conversion ratio and the catalytic ability of toluene oxidation was in the order of ZnO-CuO>$Fe_2O_3$>NiO>ZnO>CrO. We found that the acid aqueous pre-treatment (0.1 N HNO$_3$) was the best way to enhance the catalytic activity of $Fe_2O_3$. In addition, air and hydrogen gas treatment were optimal for NiO and ZnO-CuO catalysts, respectively. Furthermore, the decomposition of BTX depends on the type of a catalyst and a gas molecule.

• 자원리싸이클링
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• 제28권6호
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• pp.36-45
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• 2019

석유화학공정에서 발생하는 폐촉매는 바나듐, 몰리브덴, 니켈, 코발트와 같은 희유금속을 함유하고 있다. 유기산에 의한 상기 금속의 침출에 대해 연구하였다. 본 논문에서 사용한 유기산에 의한 금속의 침출률은 옥살산 > 타르타르산 > 구연산 > 말레산 > 오스코브르산 순서이었다. 상기 유기산은 바나듐과 몰리브덴의 침출에 선택성이 있으며 옥살산에 의한 침출률이 가장 높았다. 옥살산의 농도, 반응온도, 광액밀도, 교반속도를 변화시켜 옥살산에 의한 바나듐의 최적침출조건을 얻었다. 옥살산에 의한 바나듐의 침출에 대한 속도식을 조사한 결과 Avrami식과 잘 맞았으며 활성화에너지는 8.76 kJ/mol로 물질전달에 의해 침출반응이 율속되었다.

• 대한방사성의약품학회지
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• 제7권2호
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• pp.141-146
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• 2021

With increasing interest in fluorinated compounds, nucleophilic fluorination reaction has been generally used for synthesizing fluorine-containing chemicals. However, alkali metal fluorides (MFs) generally have low solubility and reactivity in organic solvent. To overcome these problems, various phase transfer catalysts (PTCs) have been investigated. Calix-arene is known as to capture the metal cation(M⁺), and therefore in this review, we would like to introduce several kinds of calix-arene based PTCs, such as bis-tert-alcohol-functionalized crown-6-calix[4]arene (BACCA), oligo-ethylene glycol linked bis-triethyleneglycol crown-5-calix[4]arene (BTC5A), and ionic liquid functionalized calix-arene based catalyst, as well as ion-pair receptor crown-6-calix[4]arene-capped calix[4]pyrrole.

• Journal of Electrochemical Science and Technology
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• 제15권2호
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• pp.207-219
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• 2024

Metal-N-C (MNC) catalysts have been anticipated as promising candidates for oxygen reduction reaction (ORR) to achieve low-cost polymer electrolyte membrane fuel cells. The structure of the M-N_x moiety enabled a high catalytic activity that was not observed in previously reported transition metal nanoparticle-based catalysts. Despite progress in non-precious metal catalysts, the low density of active sites of MNCs, which resulted in lower single-cell performance than Pt/C, needs to be resolved for practical application. This review focused on the recent studies and methodologies aimed to overcome these limitations and develop an inexpensive catalyst with excellent activity and durability in an alkaline environment. It included the possibility of non-precious metals as active materials for ORR catalysts, starting from Co phthalocyanine as ORR catalyst and the development of methodologies (e.g., metal-coordinated N-containing polymers, metal-organic frameworks) to form active sites, M-N_x moieties. Thereafter, the motivation, procedures, and progress of the latest research on the design of catalyst morphology for improved mass transport ability and active site engineering that allowed the promoted ORR kinetics were discussed.

• Bulletin of the Korean Chemical Society
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• 제26권12호
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• pp.2017-2020
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• 2005

The supported bimetallic Co-containing catalysts promoted by the different amount of noble metal (Pd) have been studied in the dry reforming of methane. The activity, selectivity, stability and resistance to the carbon deposition of Co-Pd/$Al_2O_3$ catalysts depend on both the catalyst composition and process conditions. It has been observed that the Co-Pd/$Al_2O_3$ catalysts produce the various oxygenates from $CO_2$ + $CH_4$ at moderate pressures.

• 공업화학
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• 제30권5호
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• pp.513-522
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• 2019

유기물질, 전이금속 및 유기-금속 구조체(MOFs)를 기반으로 하는 촉매들이 유기인 계열 독성물질들을 분해하고 제거하는데 효과적임이 보고되어 왔다. 최근 20년간 독성물질 분해연구를 위해 다공성 MOFs들이 응용 목적에 맞게 디자인되고 합성되었다. $Zr_6$ 기반의 금속노드와 유기결합체를 가지는 MOFs들은 세공크기, 공극률, 표면적, Lewis acidic 자리 그리고 열적 안정성 등과 같은 기본구조내의 변형이 가능하기 때문에 화학작용제, 살충제 및 제초제를 제거하는 촉매로 널리 사용되어왔다. 본 리뷰에서는 구조, 안정성, 입자크기, 연결된 리간드 수, 유기 기능기 등에 따른 MOFs들의 촉매효율과의 연관성을 다루게 될 것이다.

• Nano
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• 제13권11호
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• pp.1850132.1-1850132.14
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• 2018

The direct synthesis of metal-organic frameworks (MOFs) with acidic and basic active sites is challenging due to the introduction of functional groups by post-functionalization method often jeopardize the framework integrity. Herein, we report the direct synthesis of acid-base bifunctional MOFs with tuning acid-base strength. Employing modulated hydrothermal (MHT) approach, microporous MOFs named $UiO-66-NH_2$ was prepared. Through the ring-opening reaction of 1,3-propanesultone with amino group, $UiO-66-NH_2-SO_3H-type$ catalysts can be obtained. The synthesized catalysts were well characterized and their catalytic performances were evaluated in one-pot glucose to 5-HMF conversion. Results revealed the acid-base bi-functional catalyst possessed high activity and excellent stability. This work provides a general and economically viable approach for the large-scale synthesis of acid-base bi-functional MOFs for their potential use in catalysis field.

• 대한화학회지
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• 제68권2호
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• pp.87-92
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• 2024

The commercialization of rechargeable metal-air batteries is extremely desirable but designing stable oxygen reduction reaction (ORR) catalysts with non-noble metal still has faced challenges to replace platinum-based catalysts. The nonnoble metal catalysts for ORR were prepared to improve the catalytic performance and stability by the thermal decomposition of ZIF-8 with optimum cobalt loading. The porous carbon was obtained by the calcination of ZIF-8 and different loading amounts of Co nanoparticles were anchored onto porous carbon forming a Co/PC catalyst. Co/PC composite shows a significant increase in the ORR value of current and stability (500 h) due to the good electronic conductive PCN support and optimum cobalt metal loading. The significantly improved catalytic performance is ascribed to the chemical structure, synergistic effects, porous carbon networks, and rich active sites. This method develops a new pathway for a highly active and advantageous catalyst for electrochemical devices.