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박대원,우희철,Bong-Kuk Kim,Byung-Ha Hwang,Hwa-Soo Lee 한국화학공학회 2004 Korean Journal of Chemical Engineering Vol.21 No.1
The selective oxidation of hydrogen sulfide in the presence of excess water and ammonia was investigated by using vanadium-bismuth based mixed oxide catalysts. Synergistic effect on catalytic activity was observed for the mechanical mixtures of V-Bi-O and Sb2O4. Temperature programmed oxidation (TPO), X-ray photoelectron spectroscopy (XPS), and two separated bed reactivity test results supported the role of Sb2O4 for reoxidizing the reduced VBi- O during the reaction.
박대원,Kyung-Hoon Kim,Dong-Woo Kim,Cheol-Woong Kim,Jae-Cheon Koh 한국화학공학회 2010 Korean Journal of Chemical Engineering Vol.27 No.5
Ionic liquid immobilized on commercial silica catalysts proved to be an effective heterogeneous catalyst for the synthesis of dimethyl carbonate (DMC) from transesterification of ethylene carbonate (EC) with methanol. The immobilized 1-n-alkyl imidazolium halide ionic liquid on commercial silica (RImX-CS) was characterized by EA,BET, FT-IR, 13C NMR and 29Si NMR. It was found that RImX-CS with a longer alkyl chain length showed much better catalytic activity. RImX-CS with chloride (Cl−) as the counter anion showed the best catalytic activity. High temperature,high carbon dioxide pressure, and longer reaction time were favorable for the reactivity of BuImBr-CS. The catalyst can be reused for the reaction up to three consecutive runs without any considerable loss of its initial activity.
아크롤레인 선택 산화반응에서 Mo - V - O 와 금속산화물의 상간협동
박대원,나석은,김경훈,이원호,정종식 ( D . W . Park,S . E . Na,K . H . Kim,W . H . Lee,J . S . Chung ) 한국공업화학회 1994 공업화학 Vol.5 No.2
본 연구는 아크롤레인의 선택산화반응에서 Mo-V-O와 금속산화물의 기계적 혼합촉매에 대한 synergy 효과를 고찰한 것으로 금속산화물로는 SnO_2, α-Sb_2O_4, WO_3, α-Al_2O_3, CuO, MnO_2, Cu_2O, MgO, CoO 그리고 ZnO 등을 사용하였다. SnO_2나 α-Sb_20_4와 Mo-V-O의 혼합물 촉매는 Mo-V-0보다 높은 전화율과 수율을 나타내었는데 이것은 이들이 산소빈자리에 해리 흡착된 산소를 형성하여 Mo-V-O에 전달하는 상간협동에 의한 것으로 판단된다. 그러나 Cu_2O, MgO, CuO, MnO_2와 Mo-V-O의 혼합물 촉매의 경우 전화율은 증가하였으나 수율은 감소하였고, CoO와 ZnO는 Mo-V-O의 촉매성능을 억제하였다. 각 금속산화물의 역할이 서로 다른 점을 그들의 산화-환원 특성으로 설명하였다. The synergistic effects in mechanical mixture catalysts of Mo-V-0 and metal oxide were investiegated for the selective oxidation of acrolein. The metal oxides used are SnO_2, α-Sb_20_4, WO_3, α-Al_2O_3, CuO, MnO_2, Cu_2O, MgO, CoO, and ZnO. Mechanical mixtures of Mo-V-O plus SnO_2 or α-Sb_2O_4 had resulted in higher conversion of acrolein and higher yield of acrylic acid than Mo-V-O. The origin of the synergy is attributed to the cooperation of Mo-V-O and SnO_2 or α-Sb_2O_4, in which SnO_2 or α-Sb_2O_4 forms dissociated oxygens at their oxygen vacancies and transports them to Mo-V-O. Cu_2O, MgO, CuO, and MnO_2, increased conversion of acrolein but decreased yield of acrylic acid. CoO and ZnO inhibited the catalytic performance of Mo-V-O. The different role of these metal oxides is explained in terms of their oxidation-reduction properties.
박대원,Hye-Young Ju,Ji-Yeon Ahn,Mamparambath-Dharman Manju,Kyung-Hoon Kim 한국화학공학회 2008 Korean Journal of Chemical Engineering Vol.25 No.3
The catalytic performance of pyridinium salt ionic liquids in the reaction of butyl glycidyl ether and carbon dioxide was investigated in this study. The catalytic activity was studied in a batch reactor with different 1-alkylpyridinium salt ionic liquids at 60-140 oC. The conversion of butyl glycidyl ether was affected by the structure of the ionic liquid; the one with the cation of bulkier alkyl chain length showed better reactivity. The effect of carbon dioxide pressure, reaction temperature and zinc bromide co-catalyst on this reaction was also discussed.
박대원,Hye-Young Ju,Mamparambath Dharman Manju,Kyung-Hoon Kim,박상욱 한국화학공학회 2007 Korean Journal of Chemical Engineering Vol.24 No.5
with methanol was investigated by using imidazolium salt ionic liquid catalysts. 1-alkyl-3-methyl imidazolium saltsof different alkyl group (C2, C4, C6, C8) and anions (Cl, Br,BF4, PF6) were used for catalysts. The reaction was carriedout in an autoclave at 140-180oC under carbon dioxide pressure of 1.48-5.61 MPa. The imidazolium salts of shorteras CO2 pressure and reaction temperature increased. Kinetic studies were also performed to better understand the reac-tion mechanism.
박대원,백경란,정문현,이진서,박윤수,김효열,이미숙,Jung Yeon Kim,염준섭,김민자 대한의학회 2012 Journal of Korean medical science Vol.27 No.5
The efficacy and safety of ertapenem, 1 g once daily, were compared with that of ceftriaxone, 2 g once daily, for the treatment of adults with acute pyelonephritis (APN)and complicated urinary tract infections (cUTIs) in a prospective, multicenter, doubleblinded,randomized study. After ≥ 3 days of parenteral study therapy, patients could be switched to an oral agent. Of 271 patients who were initially stratified by APN (n = 210) or other cUTIs (n = 61), 66 (48.9%) in the ertapenem group and 71 (52.2%) in the ceftriaxone group were microbiologically evaluable. The mean duration of parenteral and total therapy,respectively, was 5.6 and 13.8 days for ertapenem and 5.8 and 13.8 days for ceftriaxone. The most common pathogen was Escherichia coli. At the primary efficacy endpoint 5-9 days after treatment, 58 (87.9%) patients in the ertapenem group and 63 (88.7%) in the ceftriaxone had a favorable microbiological response. When compared by stratum and severity, the outcomes in the two groups were equivalent. The frequency and severity of drug-related adverse events were generally similar in both treatment groups. The results indicate that ertapenem is highly effective and safe for the treatment of APN and cUTIs.
박대원,Ji-Yeon Ahn,Hye-Lim Shim,Kyung-Hoon Kim,김일,박상욱 한국화학공학회 2008 Korean Journal of Chemical Engineering Vol.25 No.4
The copolymerization of phenyl glycidyl ether (PGE) and carbon dioxide was performed in the presence of ionic liquid catalyst. 1-Butyl-3-methyl imidazolium chloride, tetrabutylamouim chloride and 1-n-butylpyridinium chloride were used as catalyst for this reaction carried out in a batch reactor. All the ionic liquid catalysts showed good catalytic activity for the synthesis of polycarbonates with very low polydispersity, close to 1. The carbonate content, turnover number (TON), and average molecular weight of the copolymer were affected by the structure of the ionic liquid. High carbon dioxide pressure enhanced TON and carbonate content because of the increase of carbon dioxide absorption in PGE solution. ZnBr2 and a Zn-Co cyanide complex were also tested as a catalyst and/or cocatalyst for this reaction to compare their catalytic performance with the imidazolium salt ionic liquids
박대원,Mi-Kyung Lee,Hye-Lim Shim,Manju Mamparambath Dharman,Kyung-Hoon Kim,박상욱 한국화학공학회 2008 Korean Journal of Chemical Engineering Vol.25 No.5
A silica-supported ionic liquid (Im-IL) was proven to be an effective heterogeneous catalyst for solventless synthesis of cyclic carbonate from allyl glycidyl ether (AGE) and carbon dioxide. Im-IL catalysts were prepared by sol-gel method. The synthesis of cyclic carbonate from AGE and CO2 was carried out in a batch autoclave reactor. Im-IL with shorter alkyl chain length showed the highest conversion of AGE, probably due to the steric hindrance for the formation of intermediate from the catalyst prepared by using longer alkyl chains and AGE. High temperature and high pressure were favorable for the conversion of AGE. Im-IL can be reused for the reaction up to two consecutive runs without any considerable loss of its catalytic activity.
박대원,Hong Rok Kim,Jayeeta Chattopadhyay,Jae Ik Son 한국화학공학회 2008 Korean Journal of Chemical Engineering Vol.25 No.4
Pure TiO2 hollow spheres were prepared by using poly(styrene-methacrylic acid) latex particles as template; thereafter, titania hollow spheres were coated by platinum with an appropriate amount of choloroplatinic acid solution to obtain Pt/TiO2 catalysts. The morphology and structure of nonstructural Pt/TiO2 hollow spheres were characterized by BET, XRD, TGA, SEM and TEM analysis. In the samples, a remarkably uniform layer of Pt consisting of particles from 5 to 70 nm in size was formed over TiO2 hollow spheres. We found the electrocatalytic nature of the samples by cyclic voltammetric experiment in acidic solution. The anodic peak current density of 20 wt% Pt-loaded TiO2 hollow particles was observed 2.5 times higher than that of 5 wt% Pt/TiO2 in the same experimental condition. Also, the anodic current density of 20 wt% Pt/TiO2 hollow spheres calcined at various temperatures followed the order: 400 oC≈500 oC>600 oC. The electrocatalytic activity of the Pt-loaded TiO2 hollow spheres depends on the amount of atomic platinum present in the sample; a higher concentration of platinum results in a larger current density value in anodic sweep, resulting in more oxygen production during electrolysis. Pt/TiO2 hollow sphere catalysts have also shown long term electrocatalytic stability in acidic media.
박대원,Jeong-In Yu,Hye-Young Ju,Kyung-Hoon Kim 한국화학공학회 2010 Korean Journal of Chemical Engineering Vol.27 No.2
The catalytic performance of imidazolium salt ionic liquids in the cycloaddition of carbon dioxide to butyl glycidyl ether (BGE) was investigated. The catalytic activity was tested with different imidazolium salt ionic liquids at 60-140 oC under 0.62-2.17MPa of CO2 pressure. The imidazolium salt ionic liquid with the cation of bulkier alkyl chain length and with more nucleophilic anion showed higher conversion of BGE. High carbon dioxide pressure and high reaction temperature up to 140 oC was favorable for the high reactivity of the catalyst. The presence of zinc bromide co-catalyst enhanced the reactivity of the imidazolium salt ionic liquid. Kinetic studies with a semi-batch reactor revealed that the reaction could be considered as first order with respect to the concentration of BGE, and the activation energy was estimated as 22.6 and 22.8 kJ/mol for 1-ethyl-3-methylimidazolium chloride (EMImCl) and 1-butyl-3-methylimidazolium chloride (BMImCl), respectively.