• Title/Summary/Keyword: reactions

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Ionic Liquids: An Environmentally Friendly Media for Nucleophilic Substitution Reactions

  • Jorapur, Yogesh R.;Chi, Dae-Yoon
    • Bulletin of the Korean Chemical Society
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    • v.27 no.3
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    • pp.345-354
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    • 2006
  • Ionic liquids are alternative reaction media of increasing interest and are regarded as an eco-friendly alternatives, of potential use in place of the volatile organic solvents typically used in current chemical processing methods. They are emerging as the smart and excellent solvents, which are made of positive and negative ions that they are liquids near room temperature. The nucleophilic substitution reaction is one of the important method for inserting functional groups into a carbon skeleton. Many nucleophilic substitution reactions have been found with enhanced reactivity and selectivity in ionic liquid. In this review, some recent interesting results of nucleophilic substitution reactions such as hydroxylations, ether cleavages, carbon-X (X= carbon, oxygen, nitrogen, fluorine) bond forming reactions, and ring opening of epoxides in ionic liquids are discussed.

Inertial Dynamic Effect on the Rates of Diffusion-Controlled Ligand-Receptor Reactions

  • Lee, Woo-Jin;Kim, Ji-Hyun;Lee, Sang-Youb
    • Bulletin of the Korean Chemical Society
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    • v.32 no.spc8
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    • pp.2973-2977
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    • 2011
  • It has been known that the inertial dynamics has a little effect on the reaction rate in solutions. In this work, however, we find that for diffusion-controlled reactions between a ligand and a receptor on the cell surface there is a noticeable inertial dynamic effect on the reaction rate. We estimate the magnitude of the inertial dynamic effect by comparing the approximate analytic results obtained with and without the inertial dynamic effect included. The magnitude of the inertial dynamic effect depends on the friction coefficient of the ligand as well as on the relative scale of the receptor size to the distance traveled by the ligand during its velocity relaxation time.

Diffusion-Influenced Kinetics of Reactions Involving Polymers

  • Sung, Jae-Young;Park, Pyeong-Jun;Lee, Jin-Uk;Lee, Woo-Jin;Kim, Ji-Hyun;Lee, Sang-Youb
    • Bulletin of the Korean Chemical Society
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    • v.24 no.6
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    • pp.843-852
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    • 2003
  • We present a brief account of the theory of diffusion-influenced kinetics of reactions involving polymers. The review will be based on the recent contributions from the authors. Both intrapolymer and interpolymer reactions are considered, and the effects of various physical factors, such as the chain length, chain stiffness, and hydrodynamic interactions, are described within a unified theoretical framework.

New and General Methods for the Synthesis of Arylmethylene Bis(3-Hydroxy-2-Cyclohexene-1-Ones) and Xanthenediones by EDDA and In(OTf)3-Catalyzed One-Pot Domino Knoevenagel/Michael or Koevenagel/Michael/Cyclodehydration Reactions

  • Jung, Doo-Hwan;Lee, Yong-Rok;Kim, Sung-Hong;Lyoo, Won-Seok
    • Bulletin of the Korean Chemical Society
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    • v.30 no.9
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    • pp.1989-1995
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    • 2009
  • Efficient one-pot synthesis of arylmethylene bis(3-hydroxy-2-cyclohexene-1-ones) and xanthenediones by EDDA and In($OTf)_3$-catalyzed reactions was developed starting from dimedone and aryl aldehydes. The key strategies of these reactions involve domino Knoevenagel/Michael reaction or Koevenagel/Michael/Cyclodehydration reactions. The scope and limitation of the two catalysts under various reaction conditions were investigated and described.

Immune reactions and allergy in experimental anisakiasis

  • Cho, Sung-Weon;Lee, Haneul-Nari
    • Parasites, Hosts and Diseases
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    • v.44 no.4 s.140
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    • pp.271-283
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    • 2006
  • The third-stage larvae (L3) of the parasitic nematode, Anisakis simplex, have been implicated in the induction of hyperimmune allergic reactions in orally infected humans. In this work, we have conducted a review of an investigation into immune reactions occurring in animals experimentally infected with A. simplex L3. The patterns of serum antibody productions if the experimental animals against excretory-secretory products (ESP) of A. simplex L3 contributed to our current knowledge regarding specific humoral immune reactions in humans. In our review, we were able to determine that L3 infection of experimental animals may constitute a good model system for further exploration of immune mechanisms and allergy in anisakiasis of humans.

The Influence of Aminium Radical Heterolytic Fragmentation Rates on the Nature and Efficiencies of SET-Promoted Photochemical Reactions

  • Yoon, Ung-Chan;Patrick S. Mariano
    • Journal of Photoscience
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    • v.10 no.1
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    • pp.89-96
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    • 2003
  • Two important types of $\alpha$-heterolytic fragmentation reactions of aminium radicals are discussed. In these fragmentation processes, transfer of electrofugal groups from the aminium radicals to either Lowry-Bronsted or Lewis bases produces $\alpha$-amino radicals. The results of recent studies that provided key information about the dynamics of the important aminium radical fragmentation reactions, deprotonation, desilylation, are summarized. Finally, selected examples, which demonstrate how knowledge of the relative rates of aminium radical cleavage can be used to design synthetically relevant SET-promoted photocyclization reactions, are presented.

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Enzyme Reactions in Organic Solvents on the Biosurfactant (미생물 계면활성제에 있어 유기용매중의 효소반응)

  • Nam, Ki-Dae;Kim, Sang-Chun;Choi, Jae-Hyo
    • Journal of the Korean Applied Science and Technology
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    • v.10 no.1
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    • pp.9-22
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    • 1993
  • Recent studies on enzyme reactions in organic solvents are revived. The reactions are classified into three categories: heterogeneous, biphasic and homogeneous systems. The following subjects are described and discussed about the heterogeneous system. 1) The maximal expression of enzyme activity in organic solvents in terms of water content, hydration of enzyme, and equilibriun of water between enzyme and substrate solution. 2) Solvent effect on the catalytic power of enzyme. 3) Thermostability and thermoreactivity. 4) Applications of the enzyme reactions to synthetic chemistry.

The Development of Moral Emotional Understanding in Preschool Children : The Influence of Offenders' Intentions and Victims' Reactions (유아의 도덕적 정서 이해의 발달 : 가해자 의도와 피해자 반응의 영향)

  • Song, Ha-Na
    • Korean Journal of Child Studies
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    • v.33 no.2
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    • pp.1-12
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    • 2012
  • This study examined the influences of age, offenders' intention, victims' emotional reactions on the moral emotional understanding of preschool children. Eighty eight children aged 4, 5, and 6 participated in this study, and were interviewed using four moral transgression stories. The responses of the children were then analyzed in terms of the levels of moral emotional understanding, from error through to the understanding of secondary emotions. The results indicated that older children showed higher levels of moral emotional understanding than younger children. Additionally, children's moral emotional understanding was higher in situations in which offenders' behaviors were intentional, and in which the victims expressed sadness. The attribution of moral emotions was influenced by victims' emotional reactions only in 6-year-old children. Discussion of these results also included the development of intervention programs for children with aggressive behaviors, as well as a number of suggestions for future study.

Feasibility Test for Radical reactions in Organic Light Emitting Diode (유기 발광 다이오드 내부의 라디칼 반응 가능성 검사)

  • Han, Chul-Hee
    • Journal of Institute of Control, Robotics and Systems
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    • v.14 no.4
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    • pp.365-368
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    • 2008
  • Feasibility test for radical reactions in organic light emitting diode(OLED) has been applied on OLED consisting of hole transport layer(HTL) and electron transport layer(ETL). Organic molecules such as 4,4',-Bis[N-(1-naphthyl)-N-phenylamino] biphenyl(NPD) and 4,4',4"-tris(3-methylphenylphenylamino)triphenylamine(m-MTDATA) are chosen for hole transport layer(HTL) and Bathocuproine(BCP) for electron transport layer(ETL) in this study. Informations on energy and shape of frontier orbitals and data on radical reactions of simple aromatics from semiconductor($TiO_2$) photocatalysis have provided basis for determining feasibility for radical reactions in OLED. The outcome of our feasibility test would be useful in designing optimum molecule for organic layer with a view to extending the lifetime of OLED.

Kinetics and Mechanism for Reactions of Substituted Phenacyl Bromides with Quinoline (치환 브롬화페나실과 퀴놀린과의 반응에 관한 반응속도론적 연구)

  • Kim, Chang-Suk;Hong, Soon-Yung
    • Journal of the Korean Chemical Society
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    • v.28 no.4
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    • pp.265-268
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    • 1984
  • Rates of reactions of nine m-or p-substituted phenacyl bromides with quinoline in methanol were measured by an electric conductivity method. These reactions were found to proceed through an $S_N2$ path and were accelerated by both electron-donating and electron-withdrawing substituents. A plausible reaction mechanism for this observation was proposed. Some activation parameters for these reactions were also calculated.

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