• Title/Summary/Keyword: supported catalysts

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Synthesis of Styrenated Phenol Alkoxylate from Styrenated Phenol with Ethylene Carbonate over KOH/La2O3 Catalyst (KOH/La2O3 촉매상에서 Styrenated Phenol과 Ethylene Carbonate의 반응으로부터 Styrenated Phenol Alkoxylate의 합성)

  • Lee, Seungmin;Son, Seokhwan;Jung, Sunghun;Kwak, Wonbong;Shin, Eun Ju;Ahn, Hogeun;Chung, Minchul
    • Applied Chemistry for Engineering
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    • v.29 no.1
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    • pp.62-66
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    • 2018
  • Styrenated phenol alkoxylates (SP-A) were prepared from styrenated phenol (SP) and ethylene oxide (EO) under a homogeneous base catalyst. However, to use EO that is difficult to handle, a high-pressure reaction device capable of controlling the reaction process should be used. Additionally, when a homogeneous base catalyst is used, a neutralization process is required to remove residual bases after the reaction, and it is also difficult to separate the catalyst and the product. Therefore, in this study, we report the results of SP-A prepared from the reaction of SP and EC using only heterogeneous base catalysts. The heterogeneous base catalyst was obtained by supporting KOH on $La_2O_3$ and calcintion. Using EC instead of EO, it was possible to produce SP-A under the atmospheric rather than high-pressure reaction condition. Average molecular weights of synthesized SP-A varied greatly depending on reaction conditions. The average molecular weight of SP-A prepared using the $KOH/La_2O_3$ catalyst could be controlled arbitrarily by controlling the reaction temperature and added catalyst and EC amounts.

Hydrogenation Characteristics of Aromatics in Residue Oil of Naphtha Cracking on Pt/Pd Impregnated Mesoporous Molecular Sieve (메조포러스 분자체에 담지된 Pt/Pd 촉매상에서 납사분해 잔사유의 방향족 화합물 수소화 특성)

  • Choi, Jong Hwa;Jeong, Soon Yong;Oh, Sung-Geun
    • Korean Chemical Engineering Research
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    • v.43 no.6
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    • pp.675-682
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    • 2005
  • Al containing mesoporous molecular sieve (Al-MMS) was synthesized by hydrolysis of $H_2SiF_6$ and $Al(NO_3)_3{\cdot}9H_2O$. The material obtained was characterized by XRD, $N_2$-physisorption. The specific surface area was $981m^2/g$, and the average pore size was uniformity $39{\AA}$. It was confirmed that the acidity of Al-MMS was milder than that of zeolite Y based on the results of $NH_3$-TPD. Active materials, Pt and Pd, were loaded on Al-MMS in order to examine the feasibility of using Al-MMS as a catalyst support in the hydrogenation of aromatic compounds included in the residue oil of a naphtha cracker. The hydrogenation activity of PtPd/Al-MMS has been studied by following the kinetics of the hydrogenation of naphthalene, and by comparing the kinetic parameters obtained with Pt and Pd catalysts supported on the other mesoporous material support and commercial conventional support materials. PtPd/Al-MMS catalyst shows the highest activity of hydrogenation and sulfur resistance. The high activity of PtPd/Al-MMS was confirmed again in the hydrogenation of PGO (pyrolized gas oil), which is residue oil obtained from a naphtha cracker. Therefore, PtPd/Al-MMS can be applied to the hydrogenation of aromatic compounds included in the residue oil of a commercial naphtha cracker commericially.

An Oxyfluorination Effect of Carbon Nanotubes Supports on Electrochemical Behaviors of Platinum Nanoparticle Electrodes (백금 나노입자전극의 전기화학적 거동에 대한 카본나노튜브 지지체의 산소-불소 처리효과)

  • Kim, Seok;Lee, Jae-Rock;Park, Soo-Jin
    • Korean Chemical Engineering Research
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    • v.46 no.1
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    • pp.118-123
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    • 2008
  • In the present study, the effect of oxyfluorination treatment on multi-walled nanotubes (MWNTs) supports was investigated by analyzing surface functional groups. The surface characteristics were determined by Fourier transformed-infrared (FT-IR) and X-ray photoelectron spectroscopy (XPS). After the deposition of platinum nanoparticles on the above treated carbon supports, a crystalline size and a loading level had been investigated. Electrochemical properties of the treated MWNTs-supported Pt (Pt/MWNTs) catalysts were analyzed by current-voltage curve measurements. From the results of surface analysis, an oxygen and fluorine-containing functional group had been introduced to the surface of carbon supports. The oxygen and fluorine contents were the highest value at the treatment of 100 temperature. The Pt/100-MWNTs showed the smallest particle crystalline size of 3.5 nm and the highest loading level of 9.4% at the treatment of 100 temperature. However, the sample treated at the higher temperature showed the larger crystalline size and the lower loading level. This indicated that the crystalline size and the loading level could be controlled by changing the temperature of oxyfluorination treatment. Accordingly, an electrochemical activity was enhanced by increasing the temperature of treatment upto 100, and then decreased in the case of 200 and 300. The highest specific current density of 120 mA/mg had been obtained in the case of Pt/100-MWNTs.

Catalytic Decomposition of SF6 by Hydrolysis over γ - Al2O3 Supported Metal Oxide Catalysts (금속산화물이 담지된 γ - Al2O3 촉매상에서 가수분해에 의한 SF6의 촉매분해)

  • Park, Hyeon-Gyu;Park, No-Kuk;Lee, Tae-Jin;Chang, Won-Chul;Kwon, Won-Tae
    • Clean Technology
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    • v.18 no.1
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    • pp.83-88
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    • 2012
  • In order to improve the stability of ${\gamma}-Al_2O_3$ on hydrolysis of $SF_6$, the catalytic promoters were investigated in this study. The crystal phase of ${\gamma}-Al_2O_3$ is transformed to their ${\alpha}$-phase during hydrolysis of $SF_6$. Various metal oxides were applied as the promoter material that is Ga, Mg, and Zn and the promoter of 1, 5, and 10 wt% was impregnated over ${\gamma}-Al_2O_3$ by the impregnation method. Specially, it were confirmed in the catalytic activity tests and XRD analysis that ZnO/${\gamma}-Al_2O_3$ catalyst had the high activity for decomposition of $SF_6$ by catalytic hydrolysis and the crystal phase of ZnO promoted ${\gamma}-Al_2O_3$ was not transformed. From these results, it could be known that the stability of ${\gamma}-Al_2O_3$ is enhanced with the catalytic promotion of ZnO impregnated over the surface of catalyst.

Highly active and trans-1,4-specific polymerization of 1,3-butadiene catalyzed by bis(benzimidazolyl)amine chromium complexes activated with methylaluminoxane (메틸알루미녹산으로 활성화시킨 고활성 bis(benzimidazolyl)amine 크롬 착물을 이용한 부타디엔 중합에 의한 트랜스 폴리부타디엔 제조)

  • Moon, Byeong Kyu;Song, Ga Young;Zhang, Lin;Shin, Jin Young;Chang, Hyuk Chul;Shim, Sang Eun;Yun, Ju Ho;Kim, Il
    • Elastomers and Composites
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    • v.48 no.1
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    • pp.61-66
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    • 2013
  • A family of Cr(III) complexes supported on tridentate dibenzimidazolyl ligands having a general formula: $[N(CH_3)(CH_2)_2(Bm-R)_2]CrCl_3$ [where Bm = benzimidazolyl, R = H (3a); -Me(3b); -Bn (3c)] have been synthesized and utilized them for the trans-1,4-specific polymerizations of 1,3-butadiene (BD), activated with methylalumoxane (MAO). The activity of BD polymerizations was sensitive to the type of ligand on the Cr metal, so that the activity decreases in the order of 3a > 3c > 3b. All the catalysts combined with MAO yielded polybutadienes with perfect trans-1,4 structure with moderate molecular weight.

Preparation and Characterization of Cu/MCM-41 Mesoporous Catalysts for NO Removal (Cu/MCM-41 메조포러스 촉매 제조 및 NO 제거 특성)

  • Park, Soo-Jin;Cho, Mi-Hwa;Kim, Seok;Kwon, Soo-Han
    • Applied Chemistry for Engineering
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    • v.16 no.6
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    • pp.737-741
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    • 2005
  • In this study, the effect of copper content on the NO removal efficiency by Cu/MCM-41 has been investigated. MCM-41 was prepared by hydrothermal synthesis using a gel mixture of colloidal silica solution and cetyltrimethylammonium. Cu/MCM-41 was manufactured with copper content (5, 10, 20, and 40%) in Cu(II) acetylacetonate. The surface properties of MCM-41 were investigated by using pH, XRD, and FT-IR analyses. $N_2/77K$ adsorption isotherm characteristics, including the specific surface area and micropore volume were studied by BET's equation and Boer's t-plot methods. NO removal efficiency was confirmed by gas chromatography technique. From the experimental results, the MCM-41 was analyzed to have the surface functional groups of Si-OH and Si-O-Si and the characteristic diffraction lines (100), (110), (200), and (210) corresponding to a hexagonal arrangement structure. The copper content supported on MCM-41 appeared to increase the NO removal efficiency in spite of decreasing the specific surface areas or micropore volumes. Consequently, it was found that the copper content in Cu/MCM-41 played an important role in improving the NO removal efficiency, which was mainly attributed to the catalytic reactions.

Catalytic CO2 Methanation over Ni Catalyst Supported on Metal-Ceramic Core-Shell Microstructures (금속-세라믹 코어-쉘 복합체에 담지된 Ni 금속 촉매를 적용한 CO2 메탄화 반응 특성연구)

  • Lee, Hyunju;Han, Dohyun;Lee, Doohwan
    • Clean Technology
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    • v.28 no.2
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    • pp.154-162
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    • 2022
  • Microstructured Al@Al2O3 and Al@Ni-Al LDH (LDH = layered double hydroxide) core-shell metal-ceramic composites are prepared by hydrothermal reactions of aluminum (Al) metal substrates. Controlled hydrothermal reactions of Al metal substrates induce the hydrothermal dissolution of Al ions at the Al-substrate/solution interface and reconstruction as porous metal-hydroxides on the Al substrate, thereby constructing unique metal-ceramic core-shell composite structures. The morphology, composition, and crystal structure of the core-shell composites are affected largely by the ions in the hydrothermal solution; therefore, the critical physicochemical and surface properties of these unique metal-ceramic core-shell microstructures can be modulated effectively by varying the solution composition. A Ni/Al@Al2O3 catalyst with highly dispersed catalytic Ni nanoparticles on an Al@Al2O3 core-shell substrate was prepared by a controlled reduction of an Al@Ni-Al LDH core-shell prepared by hydrothermal reactions of Al in nickel nitrate solution. The reduction of Al@Ni-Al LDH leads to the exolution of Ni ions from the LDH shell, thereby constructing the Ni nanoparticles dispersed on the Al@Al2O3. The catalytic properties of the Ni/Al@Al2O3 catalyst were investigated for CO2 methanation reactions. The Ni/Al@Al2O3 catalyst exhibited 2 times greater CO2 conversion than a Ni/Al2O3 catalyst prepared by conventional incipient wetness impregnation and showed high structural stability. These results demonstrate the high effectiveness of the design and synthesis methods for the metal-ceramic composite catalysts derived by hydrothermal reactions of Al metal substrates.

Heterogeneous Oxidation of Liquid-phase TCE over $CoO_x/TiO_2$ Catalysts (액상 TCE 제거반응을 위한 $CoO_x/TiO_2$ 촉매)

  • Kim, Moon-Hyeon;Choo, Kwang-Ho
    • Journal of Korean Society of Environmental Engineers
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    • v.27 no.3
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    • pp.253-261
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    • 2005
  • Catalytic wet oxidation of ppm levels of trichloroethylene (TCE) in water has been conducted using $TiO_2$-supported cobalt oxides at a given temperature and weight hourly space velocity. 5% $CoO_x/TiO_2$ might be the most promising catalyst for the wet oxidation at $36^{\circ}C$ although it exhibited a transient behavior in time on-stream activity. Not only could the bare support be inactive for the wet decomposition reaction, but no TCE removal also occurred by the process of adsorption on $TiO_2$ surface. The catalytic activity was independent of all particle sizes used, thereby representing no mass transfer limitation in intraparticle diffusion. Characterization of the $CoO_x$ catalyst by acquiring XPS spectra of both fresh and used Co surfaces gave different surface spectral features of each $CoO_x$. Co $2p_{3/2}$ binding energy of Co species exposed predominantly onto the outermost surface of the fresh catalyst appeared at 781.3 eV, which is very similar to the chemical states of $CoTiO_x$ such as $Co_2TiO_4$ and $CoTiO_3$. The spent catalyst possessed a 780.3 eV main peak with a satellite structure at 795.8 eV. Based on XPS spectra of reference Co compound, the TCE-exposed Co surfaces could be assigned to be in the form of mainly $Co_3O_4$. XRD measurements indicated that the phase structure of Co species in 5% $CoO_x/TiO_2$ catalyst even before reaction is quite comparable to the diffraction lines of external $Co_3O_4$ standard. A model structure of $CoO_x$ present on titania surfaces would be $Co_3O_4$, encapsulated in thin-film $CoTiO_x$ species consisting of $Co_2TiO_4$ and $CoTiO_3$, which may be active for the decomposition of TCE in a flow of water.

Plasma-assisted Catalysis for the Abatement of Isopropyl Alcohol over Metal Oxides (금속산화물 촉매상에서 플라즈마를 이용한 IPA 저감)

  • Jo, Jin Oh;Lee, Sang Baek;Jang, Dong Lyong;Park, Jong-Ho;Mok, Young Sun
    • Clean Technology
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    • v.20 no.4
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    • pp.375-382
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    • 2014
  • This work investigated the plasma-catalytic decomposition of isopropyl alcohol (IPA) and the behavior of the byproduct compounds over monolith-supported metal oxide catalysts. Iron oxide ($Fe_2O_3$) or copper oxide (CuO) was loaded on a monolithic porous ${\alpha}-Al_2O_3$ support, which was placed inside the coaxial electrodes of plasma reactor. The IPA decomposition efficiency itself hardly depended on the presence and type of metal oxides because the rate of plasma-induced decomposition was so fast, but the behavior of byproduct formation was largely affected by them. The concentrations of the unwanted byproducts, including acetone, formaldehyde, acetaldehyde, methane, carbon monoxide, etc., were in order of $Fe_2O_3/{\alpha}-Al_2O_3$ < $CuO/{\alpha}-Al_2O_3$ < ${\alpha}-Al_2O_3$ from low to high. Under the condition (flow rate: $1L\;min^{-1}$; IPA concentration: 5,000 ppm; $O_2$ content: 10%; discharge power: 47 W), the selectivity towards $CO_2$ was about 40, 80 and 95% for ${\alpha}-Al_2O_3$, $CuO/{\alpha}-Al_2O_3$ and $Fe_2O_3/{\alpha}-Al_2O_3$, respectively, indicating that $Fe_2O_3/{\alpha}-Al_2O_3$ is the most effective for plasma-catalytic oxidation of IPA. Unlike plasma-alone processes in which tar-like products formed from volatile organic compounds are deposited, the present plasma-catalyst hybrid system did not exhibit such a phenomenon, thus retaining the original catalytic activity.

Effect of SO2 on the Simultaneous Removal of Mercury and NOx over CuCl2-loaded V2O5-WO3/TiO2 SCR Catalysts (CuCl2가 담지된 V2O5-WO3/TiO2 SCR 촉매에 의한 수은 및 NOx 동시 제거에서 SO2의 영향)

  • Ham, Sung-Won
    • Clean Technology
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    • v.28 no.1
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    • pp.38-45
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    • 2022
  • CuCl2-loaded V2O5-WO3/TiO2 catalyst showed excellent activity in the catalytic oxidation of elemental mercury to oxidized mercury even under SCR condition in the presence of NH3, which is well known to significantly inhibit the oxidation activity of elemental mercury by HCl. Moreover, it was confirmed that, when SO2 was present in the reaction gas together with HCl, excellent elemental mercury oxidation activity was maintained even though CuCl2 supported on the catalyst surface was converted to CuSO4. This is thought to be because not only HCl but also the SO4 component generated on the catalyst surface promotes the oxidation of elemental mercury. However, in the presence of SO2, the total mercury balance before and after the catalytic reaction was not matched, especially as the concentration of SO2 increased. In order to understand the cause of this, further studies are needed to investigate the effect of SO2 in the SnCl2 aqueous solution employed for mercury species analysis and the effect of sulfate ions generated on elemental mercury oxidation. It was confirmed that SO2 also promotes NOx removal activity, which is thought to be because the increase in acid sites by SO4 generated on the catalyst surface by SO2 facilitates NH3 adsorption. The composition change and structure of the components present on the catalyst surface under various reaction conditions were measured by XRD and XRF. These measurement results were presented as a rational explanation for the results that SO2 enhances the oxidation activity of elemental mercury and the NOx removal activity in this catalyst system.