• Title/Summary/Keyword: methanol decomposition

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Direct Synthesis of H2O2 over Ti-Containing Molecular Sieves Supported Gold Catalysts: A Comparative Study for In-situ-H2O2-ODS of Fuel

  • Zhang, Han;Liu, Guangliang;Song, Haiyan;Chen, Chunxia;Han, Fuqin;Chen, Ping;Zhao, Zhixi;Hu, Shaozheng
    • Bulletin of the Korean Chemical Society
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    • v.34 no.10
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    • pp.3065-3072
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    • 2013
  • Direct synthesis of $H_2O_2$ and in situ oxidative desulfurization of model fuel over Au/Ti-HMS and Au/TS-1 catalysts has been comparatively investigated in water or methanol. Maximum amount (82%) of active $Au^0$ species for $H_2O_2$ synthesis was obtained. Au/Ti-HMS and Au/TS-1 exhibited the contrary performances in $H_2O_2$ synthesis as $CH_3OH/H_2O$ ratio of solvent changed. $H_2O_2$ decomposition and hydrogenation in water was inhibited by the introduction of methanol. Effect of $O_2/H_2$ ratio on $H_2O_2$ concentration, $H_2$ conversion and $H_2O_2$ selectivity revealed a relationship between $H_2O_2$ generation and $H_2$ consumption. The highest dibenzothiophene removal rate (83.2%) was obtained over Au/Ti-HMS in methanol at 1.5 of $O_2/H_2$ ratio and $60^{\circ}C$. But removal of thiophene over Au/TS-1 should be performed in water without heating to obtain a high removal rate (61.3%). Meanwhile, $H_2$ conversion and oxidative desulfurization selectivity of $H_2$ were presented.

Study on Methanol Conversion Efficiency of Steam-Methanol Reforming on Pipe Shape and Flow Rate Variation in Curved Channel (수증기-메탄올 개질기의 곡유로 채널형 관 형태 변화에 따른 메탄올 전환율 및 유동 특성에 관한 수치해석적 연구)

  • Seong, Hong Seok;Lee, Chung Ho;Suh, Jeong Se
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.40 no.3
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    • pp.173-179
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    • 2016
  • This is a numerical study on the curved channel type of hydrogen reformer using the commercial code of fluid dynamics. We numerically compared the numerical model in a previous study model and the modelling of a tube type curved channel. In the result of numerical analysis on 4 types of curved channel reformers, the methanol conversion efficiency of type 1~4 were 45.0%, 45.3%, 45.6%, 45.6% respectively, and there was hardly any difference by ${\pm}0.6%$. In light of flow characteristics, the rectangle type tube and the type 2 with $45^{\circ}$ turn showed most uniform flow characteristics and concentration distribution of methanol, and the circular type tube and the type 3 with $90^{\circ}$ turn had most un-uniform flow characteristics and concentration distribution of methanol. We concluded that the design for curved channel reformer has to have rectangle type tube with curve of almost $45^{\circ}$ as in the type of curved pipe with $45^{\circ}$ turn.

Development of Solvent System for Enzymatic Synthesis of N-Benzoylaspartame (N-Benzoylaspartame의 효소적 합성을 위한 용매계의 선정)

  • Han, Min-Su;Kim, Woo-Jung
    • Korean Journal of Food Science and Technology
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    • v.24 no.5
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    • pp.504-510
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    • 1992
  • Several single or mixed water-miscible organic solvent systems were investigated to develop the most effective solvent system for enzymatic synthesis of N-benzoylaspartame(BzAPM). The BzAPM was prepared by immobilized thermolysin with using N-benzoyl-L-aspartic acid(Bz-Asp) and L-phenylalanine methyl ester(PheOMe). The solubilities of BzAPM and L-phenylalanine were highest in 4.5% methanol(1.89 and 1.79%, respectively) among the solvents system investigated while a mixed solvent system of 25% dimethyl sulfoxide(DMSO) and 20% polyethylene glycol(PEG) 200 showed relatively high values. The synthetic activity of BzAPM as well as initial reaction rate were found to be high in 45% methanol, 45% DMSO and a mixed solvent of 25% DMSO and 20% PEM 200. The imobilized thermolysin was most stable in 25% DMSO and 20% PEG 200 during storage at $40^{\circ}C$ for 42 days. PheOMe in the same solvent system was also found fairly stable against non-enzymatic decomposition at $40^{\circ}C$. Based on the synthetic efficiency and stability, the solvent system containing 25% DMSO and 20% PEG 200 was selected to be appropriate for the enzymatic synthesis of BzAPM.

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Reducing Ammonia Emissions and Enhancing Plant Growth through Co-application of Microbes and Methanol in Sewage Sludge Treatment (하수슬러지 처리에서 미생물과 메탄올 적용을 통한 암모니아 배출 감소 및 식물 성장 향상 연구)

  • Jin-Won Kim;Hee-Gun Yang;Hee-Jong Yang;Myeong-Seon Ryu;Gwang-Su Ha;Su-Ji Jeong;Soo-Young Lee;Ji-Won Seo;Do-Youn Jeong
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.26 no.2
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    • pp.13-24
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    • 2023
  • Sewage sludge has been widely used as an organic fertilizer in agriculture. However, sewage sludge can cause serious malodor problems resulting from the decomposition of organic compounds in anaerobic conditions. The malodor of sewage sludge mainly occurs due to a low carbon to nitrogen ratio (C/N), high moisture, and low temperature, which are ideal conditions for ammonia emissions. Therefore, in this study, we investigated the reduction of the odor-causing ammonia nitrogen (NH3-N) in sewage sludge by co-application of microbes and methanol (MeOH). The physico-chemical properties of the municipal sewage sludge showed that the odor was mainly caused by a higher NH3-N content (2932.2 mg L-1). Supplementation with MeOH (20%) as a carbon source in the sewage sludge significantly reduced the NH3-N up to 34.2% by increasing C/N ratio. Furthermore, the sewage sludge was treated with the NH3-N reducing and plant growth promoting (PGP) bacteria Stenotrophomonas rhizophila SRCM 116907. The treatment with S. rhizophila SRCM 116907 significantly increased the seedling vigor index of Lolium perenne (10.3%) and Chrysanthemum burbankii (42.4%). The findings demonstrate that supplementing sewage sludge with methanol significantly reduces ammonia emissions, thereby mitigating malodor problems. Overall, the study highlights the potential of using a microbial and methanol approach to improve the quality of sewage sludge as an organic fertilizer and promote sustainable agriculture.

Application of Combinatorial Catalysis Techniques for Hydrogen Generation Catalysts (수소 제조 촉매 개발을 위한 조합 촉매 기법의 활용)

  • Suh, Dong-Jin;Wolf, Eduardo E.
    • Transactions of the Korean hydrogen and new energy society
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    • v.18 no.3
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    • pp.309-316
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    • 2007
  • 조합 및 고속탐색 실험 기법을 촉매 성분의 선정에 활용하였다. 소형 연료전지 작동을 위한 수소 생산에 가장 적합한 것으로 알려진 메탄을 산화 분해용 촉매의 특성을 적외선 화상 및 병렬형 반응 시스템으로 조사하였다. 반응의 모델을 먼저 제시하고 이를 근거로 Cu-Zn-Pd계 촉매를 선정하였다. 먼저 적외선 화상을 이용한 스크리닝을 위해서는 발열 효과라는 촉매 활성의 간접적인 현상을 보여줄 수 있는 적외선 민감 카메라를 이용하여 한 번에 50개의 시료 측정이 가능한 촉매 시료 배열을 설계하였다. 적외선 화상 결과로 높은 활성을 보이는 촉매 시료를 선정한 다음, 병렬형 반응 시스템과 단일 흐름 고정층 반응 시스템으로 선정된 촉매의 활성 특성을 조사 확인하였다. 본 연구에서 제시한 것과 같은 접근 방법으로 지속적으로 얻어진 결과를 반영하여 최적의 활성을 보이는 촉매 성분을 단기간에 찾아내고자 한다.

Photochemical Reaction of Nalidixic Acid in Methanol

  • Park, Hyoung-Ryun;Park, Ok-Hyun;Lee, Hong-Yune;Seo Jung-Ja;Bark, Ki-Min
    • Bulletin of the Korean Chemical Society
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    • v.24 no.11
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    • pp.1618-1622
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    • 2003
  • The photochemical reactions of methanolic nalidixic acid (NAL) solution in the absence and in the presence of air have been investigated using 300 nm UV light. From the reactions, 1-ethyl-7-methyl-4-oxo-4-hydro-1,8-naphthyridine (EMDN),formic acid, and formaldehyde are produced. In the presence of air, hydrogen peroxide is also detected along with the products listed above. The presence of oxygen during the irradiation of methanolic NAL solution effects on the product yield. The initial quantum yields of the products and of the NAL decomposition are determined. Possible reaction pathways for the photochemical reaction are suggested on the basis of the products analysis.

A Theoretical Study on the Feasibility of Long Distance Heat Transport Network Using Decomposition/Synthesis of Methanol (메탄올의 분해/합성 반응을 이용한 장거리 열수송 네트웤 구축 가능성에 대한 이론적 연구)

  • Jang, In-Sung;An, Ik-Kyoun;Han, Gui-Young;Moon, Seung-Hyun;Park, Sung-Youl;Park, Min-A;Lee, Hoon;Yoon, Seok-Mann
    • Proceedings of the Korea Society for Energy Engineering kosee Conference
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    • 2007.11a
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    • pp.187-192
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    • 2007
  • A project is being implemented to develop the long distance energy transport technology using the chemical reactions. This project can be classified into three main research categories covering heat recovery reaction, long distance energy transport, and heat generation reaction. In this study, the methanol is selected as a system material since it shows several unique superior characteristics as follows: gaseous state of reactant and product, large heat of reaction, high yields of reaction at relatively low temperature, and also steady and economical supply. Furthermore, it is anticipated that the outcomes of this study can be widely applied to the related industries. A feasibility study was carried out to evaluate the economics of this technology which study was based on the following case: 10,000 households, 15km distance energy transportation, utilization of waste heat from power plant.

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A Study on the Properties of sPEEK Electrolytic Membranes using Physical Crosslinking (물리적 가교결합을 이용한 sPEEK 전해질막의 특성에 관한 연구)

  • Oh, Sae-Joong
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.1
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    • pp.433-440
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    • 2016
  • Composite membranes were prepared by the solution casting method from sulfonated poly(etheretherketone)(sPEEK) and imidazole and phosphotungstic acid(PWA) to enhance the electrolytic properties of the membrane. TGA measurements showed that physical crosslinking due to acid-base interactions improved the thermal resistance to the desulfonation of sulfonic acid groups of the composite membrane and the addition of PWA enhanced the resistance to thermal decomposition of the composite membrane. The acid-base interaction decreased the water uptake, proton conductivity and methanol permeability of the sPEEK/imidazole composite membranes. The addition of PWA increased the proton conductivities while it decreased the water uptake and methanol permeability of sPEEK/imidazole/PWA composite membranes. Therefore, the selectivity of the composite membranes was enhanced by the addition of PWA.

Stability of Soybean Isoflavone Isomers According to Extraction Conditions

  • Choi, Yeon-Bae;Kim, Kang-Sung
    • Journal of Environmental Health Sciences
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    • v.31 no.6
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    • pp.498-503
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    • 2005
  • Stability of soybean isoflavone isomers according to extraction conditions such as temperature, pH, and extracting solvents was investigated. Heating induced three chemical reactions to occur for malony1 derivatives of isoflavones, namely decarboxylation of malony1 groups into acety1 derivatives, deesterification of malony1 residues, and hydrolysis of $\beta$-glycosidic bonds. Among the twelve isoflavone isomers, change in concentrations of acety1glycosides were most pronounced: Acety1 derivatives were present only in trace amounts in unheated hypocotyls, but the content increased dramatically during heating. As for the glycosides, concentrations of daidzin and glycitin increased due to heat treatment, though that of genistin remained almost unchanged. Heat decomposition rates and the patterns differed among the three malony1 derivatives. After 120 min at $80^{circ}C$, the relative concentrations of daidzin, glycitin and genistin were increased from $9.2\%$, $12.4\%$ and $3.3\%$ to $19.3\%$, $21.9\%$ and $6.2\%$, respectively. When crude isoflavones were solubilized in glycine buffer (pH 10.0) and incubated at $80^{circ}C$, deesterification occurred faster than at pH 7.0. When the pH of isoflavone solution was increased, the malony1glycosides were hydrolyzed to their respective glycosides at increased rate. Both acetyl and aglycone forms were unchanged and only de-esterification reactions occurred. At the acidic pH, malonylglycosides were much stable both at 60 and $80^{circ}C$. However at pH 10, $80^{circ}C$ and 1 hr, $75-80\%$ of malonylglycosides were transformed to their deesterified glycosides. When isoflavones were extracted with $60\%$ aqueous ethanol at $60^{circ}C$, isoflavone isomers were stable and the deesterification reactions did not occur in these conditions. However, at $80^{circ}C$ deesterification of malonyiglycosides occurred significantly with $15-20\%$ of malonylglycosides being hydrolyzed into their respective glycosides. This experiment showed that malonylglycosides undergo decomposition when heated or exposed to alkaline conditions. Also, aqueous ethanol was preferred to aqueous methanol as solubilizing media for obtaining extract with minimum degradation of malonylglycosides.

Syntheses and Thermal Behaviors of Rb(FOX-7)·H2O and Cs(FOX-7)·H2O

  • Luo, Jinan;Xu, Kangzhen;Wang, Min;Song, Jirong;Ren, Xiaolei;Chen, Yongshun;Zhao, Fengqi
    • Bulletin of the Korean Chemical Society
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    • v.31 no.10
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    • pp.2867-2872
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    • 2010
  • Two new energetic organic alkali metal salts, 1,1-diamino-2,2-dinitroethylene rubidium salt [Rb(FOX-7)${\cdot}H_2O$] and 1,1-diamino-2,2-dinitroethylene cesium salt [Cs(FOX-7)${\cdot}H_2O$], were synthesized by reacting of 1,1-diamino-2,2-dinitroethylene (FOX-7) and rubidium chloride or cesium chloride in alkali methanol aqueous solution, respectively. The thermal behaviors of Rb(FOX-7)${\cdot}H_2O$ and Cs(FOX-7)${\cdot}H_2O$ were studied with DSC and TG methods. The critical temperatures of thermal explosion of the two compounds are 216.22 and $223.73^{\circ}C$, respectively. Specific heat capacities of the two compounds were determined with a micro-DSC method, and the molar heat capacities are 217.46 and $199.47\;J\;mol^{-1}\;K^{-1}$ at 298.15 K, respectively. The adiabatic times-to-explosion were also calculated to be a certain value of 5.81 - 6.36 s for Rb(FOX-7)${\cdot}H_2O$, and 9.92 - 10.54 s for Cs(FOX-7)${\cdot}H_2O$. After FOX-7 becoming alkali metal salts, thermal decomposition temperatures of the compounds heighten with the rise of element period, but thermal decomposition processes become intense.