• Title/Summary/Keyword: 에틸렌 반응로

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Involvement of spermine in Control of Ethylene-Mediated Growth Response in Ranunculus sceleratus Petioles (Ranunculus sceleratus 엽병의 에틸렌 매개 생장반응조절에 있어서 Spermine의 관여)

  • 정미숙
    • Journal of Plant Biology
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    • v.35 no.4
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    • pp.425-429
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    • 1992
  • Cell elongation is known to be promoted by ethylene in petioles of Ranunculus sceleratus. Treatment of petiole segments with spermine resulted in an inhibition of cell elongation and of ethylene biosynthesis in the presence of applied auxin. Dose response curve for the spermine inhibition of auxin-induced ethylene production appeared similar to that of ACC-based ethylene production suggesting that the polyamine inhibits ethylene biosynthesis by blocking the conversion of ACC to etylene. Auxin-induced ethylene production was significantly promoted by treatment of the tissue with either DFMA or DFMO. specific inhibitors of polyamine biosynthesis. Increased level of ethylene production by DFMA was found to be completely abolished by application of exogenous spermine at a high concentration. These results indicate that endogenous spermine plays a regulatory role in the growth response of Ranunculus petioles to auxin and ethylene.hylene.

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Mass Transfer Phenomena in Polycondensation Reaction of Poly(ethylene naphthalate) (폴리(에틸렌 나프탈레이트)의 축중합 반응에서 물질 전달 현상)

  • 이성진;정성일
    • Polymer(Korea)
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    • v.28 no.2
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    • pp.121-127
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    • 2004
  • The instantaneous removal of ethylene glycol is very important fur obtaining high molecular weight polymer because of the reversibility of the polycondensation reaction of poly(ethylene naphthalate)(PEN). In this study, we investigated the mass transfer phenomena in the thin film of PEN oligomer where the polycondensation reaction took place at 280$^{\circ}C$ and under 0.1mmHg. In case of less than 0.025cm film thickness the mass transfer resistance through the thin film of the polymer melt was not so high that the overall reaction rate was governed only by the polycondenstion reaction. Both the mass transfer model and the diffusion model predicted the experimenatal data well but the diffusion model showed faster reaction rate in the low molecular weight range than the mass transfer model . It was estimated from the two models that the diffusivity was 4.7${\times}$10$\^$-6/$\textrm{cm}^2$/sec and the mass transfer coefficient was 1.4 ${\times}$10$\^$-4/cm/sec both of which were smaller than In case of poly(ethylene terephthalate).

The Effect of Adsorbed Oxygen Species on the Partial Oxidation of Ethylene over Ag/α-Al2O3 (Ag/α-Al2O3 촉매상에서의 에틸렌 부분산화반응에 미치는 흡착산소종의 영향)

  • Baik, Choong-Hoon;Lee, Sang-Gi;Yeo, Jong-Kee;Lee, Ho-In
    • Applied Chemistry for Engineering
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    • v.5 no.4
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    • pp.609-615
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    • 1994
  • Partial oxidation of ethylene over 10wt% $Ag/{\alpha}-Al_2O_3$ catalyst was studied with a pulse reactor which was connected directly to a G. C. When ethylene was injected after oxygen injection at the temperature where molecular adsorption of oxygen is difficult ethylene oxide was evolved. From the results, it is suggested that adsorbed atomic oxygen is related with the evolution of ethylene oxide. The selectivity to ethylene oxide decreased with the decrease of the amounts of adsorbed oxygen and bulk oxygen. Ethylene oxide was either decomposed to ethylene and adsorbed oxygen or isomerized to acetaldehyde. However, the isomerization of ethylene oxide to acetaldehyde was strongly suppressed by the preadsorbed oxygen.

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Photoaddition Reactions of trans-1,2-Bispyrazylethylene to Tetramethylethylene (테트라메틸에틸렌에 대한 트란스-1,2-비스피라질에틸렌의 광첨가반응)

  • Sang Chul Shim;Jin Ho Cho
    • Journal of the Korean Chemical Society
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    • v.23 no.5
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    • pp.325-328
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    • 1979
  • trans-1,2-Bispyrazylethylene (BPE) undergoes photoaddition reaction to tetramthylethylene (TME) which appears to involve radical intermediates under conditions where the corresponding hydrocarbons are unreactive. This photoaddition reaction involves abstraction of an allylic hydrogen atom of TME by $^1(n,\;{\pi}^*)$ states of BPE having radical character. The major photoadduct is isolated by column chromatography and fractional vacuum sublimation and characterized to be 2,3-dimetyl-5,6-bispyrazyl-2-hexene.

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Development of Ethylene Adsorbent for Fruits Storage (과실 저장성 향상을 위한 에틸렌 흡착제 개발)

  • Ahn, Young-Jik;Choi, Jong-Seung;Yi, Kyoung-Uk
    • The Journal of Natural Sciences
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    • v.8 no.1
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    • pp.81-85
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    • 1995
  • This experiment was conducted to develop ethylene adsorbents for removing the ethylene produced from fruit during storage. The effect of ethylene adsorbent on the removing ethylene was the highest when $ICI_3$and $KBrO_3$ were used as the base of reactant and $H_2SO_4$ auxiliary reagent of reactant. It was decreased under the saturated water vapor condition and was sligthly decreased under the high carbon dioxide condition.

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Decomposition of Ethylene by Using Dielectric Barrier Discharge Plasma (유전체 배리어 방전 플라즈마를 이용한 에틸렌의 분해)

  • Jang, Doo Il;Lim, Tae Hun;Lee, Sang Baek;Mok, Young Sun;Park, Hoeman
    • Applied Chemistry for Engineering
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    • v.23 no.6
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    • pp.608-613
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    • 2012
  • Dielectric barrier discharge plasma reactor was applied to the removal of ethylene from a simulated storage facility ($1.0m^3$) of fruits and vegetables. The system operated in a closed-loop mode by feeding the contaminated gas to the plasma reactor and recirculating the treated gas back to the storage facility. The experiments were carried out with parameters such as discharge power, circulation flow rate, initial ethylene concentration and treatment time. The rate of ethylene decomposition was mainly controlled by the discharge power and the treatment time. With the other conditions kept constant, the ethylene decomposition rate in the presence of the manganese oxide ozone control catalyst installed downstream from the plasma reactor was lower than that in the absence of it. The suggests that unreacted ozone from the plasma reactor accumulated in the storage facility where it additionally decomposed ethylene. On the basis of an initial ethylene concentration of 50 ppm, the energy requirement for completing the decomposition was about 60 kJ.

Decrosslinking of Cross-linked Polyethylene using Supercritical Methanol (초임계 메탄올을 이용한 가교 폴리에틸렌의 탈가교화)

  • Hong, Soon Man;Cho, Hang-kyu;Koo, Chong Min;Lee, Jang Hoon;Park, Wan Yong;Lee, Hong-Shik;Lee, Youn-Woo
    • Korean Chemical Engineering Research
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    • v.46 no.1
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    • pp.63-68
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    • 2008
  • We investigated the recycling method to re-plasticize cross-linked polyethylene by using supercritical methanol. The cross-linked polyethylene is successfully fragmented to thermoplasticized polyethylene with little degradation reactions in supercritical fluids. The thermo-plasticization reaction was accelerated with increase in temperature in the range from $360^{\circ}C$ to $400^{\circ}C$, resulting in decrease in crosslinking density, molecular weight and mechanical properties. However, the thermoplasticized polyethylene at $360^{\circ}C$ showed comparable tensile strength and impact strength with a raw resin of crosslinked polyethylene. Chemical structure of main chain of polyethylene was not affected by reaction condition.

Depolymerization of Polycarbonate Waste by Ethylene Glycol (에틸렌글리콜을 이용한 폐폴리카보네이트 해중합 특성)

  • Kim, Dongpil;Kim, Bo-kyung;Cho, Youngmin;Han, Myungwan;Kim, Beom-Sik
    • Korean Chemical Engineering Research
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    • v.46 no.5
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    • pp.875-879
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    • 2008
  • A method for the depolymerization of polycarbonate waste by glycolysis using ethylene glycol without catalyst was explored in order to get the monomer bisphenol A (BPA). The effect of operation variables such as reaction time, reaction temperature, EG/PC weight ratio and the kinetic of glycolysis were studied. It was found that the polymerization reaction has two different activation energies depending on the reaction temperature. A drop in activation energy with temperature indicates that the reaction mechanism has shifted from one of a succession of elementary steps to another in the series. The maximum yield of BPA of 95.6% was achieved at reaction temperature $220^{\circ}C$ for 85min with EG/PC weight ratio 4.

Electrical Discharge Plasma in a Porous Ceramic Membrane-supported Catalyst for the Decomposition of a Volatile Organic Compound (다공질 세라믹지지 촉매 상에서의 플라즈마 방전을 이용한 휘발성유기화합물의 분해)

  • Jo, Jin-Oh;Lee, Sang Baek;Jang, Dong Lyong;Mok, Young Sun
    • Applied Chemistry for Engineering
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    • v.24 no.4
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    • pp.433-437
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    • 2013
  • Electrical discharge plasma created in a multi-channel porous ceramic membrane-supported catalyst was applied to the decomposition of a volatile organic compound (VOC). For the purpose of improving the oxidation capability, the ceramic membrane used as a low-pressure drop catalyst support was loaded with zinc oxide photocatalyst by the incipient wetness impregnation method. Alternating current-driven discharge plasma was created inside the porous ceramic membrane to produce reactive species such as radicals, ozone, ions and excited molecules available for the decomposition of VOC. As the voltage supplied to the reactor increased, the plasma discharge gradually propagated in the radial direction, creating an uniform plasma in the entire ceramic membrane above a certain voltage. Ethylene was used as a model VOC. The ethylene decomposition efficiency was examined with experimental variables such as the specific energy density, inlet ethylene concentration and zinc oxide loading. When compared at the identical energy density, the decomposition efficiency obtained with the zinc oxide-loaded ceramic membrane was substantially higher than that of the bare membrane case. Both nitrogen and oxygen played an important role in initiating the decomposition of ethylene. The rate of the decomposition is governed by the quantity of reactive species generated by the plasma, and a strong dependence of the decomposition efficiency on the initial concentration was observed.

Kinetics and Mechanism of the Selective Oxidation of Ethylene for Ethylene Oxide over Monolithic Silver Catalyst (모놀리스형 은촉매상에서 에틸렌선택산화반응의 속도론적 고찰)

  • Park, Rho-Bum;Kim, Sang-Chai;Sunwoo, Chang-Sin;Yu, Eui-Yeon
    • Applied Chemistry for Engineering
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    • v.2 no.2
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    • pp.165-174
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    • 1991
  • The kinetics and the mechanism for the selective oxidation of ethylene on the supported monolithic silver catalyst were experimentally investigated in a fixed bed tubular reactor. The formation rates of ethylene oxide and carbon dioxide were measured at the atmospheric pressure with various combinations of partial pressures of ethylene and oxygen at temperature range of $225-300^{\circ}C$, conversion with 1.2-7.5 %, and then the mechanism of the selective oxidation of ethylene was verified. Their formation rates fitted with the Langmuir-Hinshelwood mechnism. The ethylene oxide and carbon dioxide are produced by reation of adsorbed ethylene with monoatomic oxygen adsorbed on the active sites of Ag-surface, and their formation rate equation are expressed as : $R_{EO}={\frac{k_1K_0{^{1/2}}K_EK_SP_{02}{^{3/2}}P_E}{(1+{\sqrt{K_0P_{02}}}+K_EP_E+K_PP_P)^2(1+{\sqrt{K_SP_{02}})^2}}$ $R_C={\frac{k_2K_0{^3}K_EK_S{^{7/2}}P_{02}{^{13/2}}P_E}{(1+{\sqrt{K_0P_{02}}}+K_EP_E+K_PP_P)^7(1+{\sqrt{K_SP_{02}})^7}}$ The activation energies of ethylene oxide and dioxide and carbon dioxide formations can be estimated to be 12.25 and 17.85 Kcal/mol, respectively.

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