• Title/Summary/Keyword: ring opening

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Ring-Opening Reaction of 2,2-gem-Diphenylaziridine (2,2-gem-Diphenylaziridine의 開環反應)

  • Hahn, Chi-Sun;Nam-Goong, Ha-Il;Kang, Yong-Ik
    • Journal of the Korean Chemical Society
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    • v.13 no.3
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    • pp.229-232
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    • 1969
  • A study of the ring-opening reaction of 2,2-gem-diphenylaziridine by treating with acetic acid has been undertaken. The structure of the ring-opened product was confirmed as 1,1-diphenyl-2-aminoethyl acetate. It is most likely that the reaction proceeds through the cleavage of a bond between nitrogen and tertiary carbon atoms in the aziridine ring, followed by the formation of a carbonium ion intermediate.

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Photo-Induced Cationic Ring-Opening Polymerization of 4-Methylene-2-styryl-1,3-dioxolane by Benzylsulfonium Salt

  • Park, Jaekyeung
    • Macromolecular Research
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    • v.9 no.4
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    • pp.206-209
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    • 2001
  • One of the approaches to obtain functional polymer is polymerization of a monomer having two functional groups. Although polymerization of a monomer having two different types of functional group is general, the author has been interested in the polymerization of a monomer having two similar types of functional group. This work shows the preparation and selective polymerization of 4-methylene-2-styryl-1,3-dioxolane having two similar reactive double bonds via cationic polymerization at ambient temperature. Cationic ring-opening polymerization of 4-methylene-2-styryl-1,3-dioxolane using benzylsulfonium salt as a photo-initiator quantitatively afforded high molecular weight of poly(keto-ether).

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Synthesis of Various Functional Block Copolymers via Controlled Ring Opening Metathesis Polymerization and the Subsequent Chemical Modifications

  • Kang, Min-Hyuk;Moon, Bong-Jin
    • Proceedings of the Polymer Society of Korea Conference
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    • 2006.10a
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    • pp.200-200
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    • 2006
  • Several polynorbornene or poly(norbornene-7-oxide) based functional block copolymers were synthesized by ring opening metathesis polymerization (ROMP) with good molecular weight and polydispersity control. Some representative functional groups in these polymers are a nitrobenzoyl group or ferrocene. These polymers were subjected to various chemical modification reactions to give other block copolymers that contain novel functionality such as amine, diazonium salt, and diazo groups. The resulting polymers were characterized by various techniques such as GPC, NMR, UV-VIS, AFM, and cyclovotammography (CV).

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Ring-opening Polymerization of an aliphatic seven-membered Cyclic Acetal (7원환 고리화합물의 개환중합)

  • Park, Jae-kyeung
    • Journal of the Korean Society of Industry Convergence
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    • v.4 no.3
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    • pp.253-255
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    • 2001
  • 기능성고분자재료 중의 하나인 7원환 고리아세탈 화합물인 1,3-dioxepan-2-one(1)을 합성하고 고온조건 하에서 중합반응을 조사한 결과 선택적인 개환중합이 일어났다. 그러나 낮은 농도에서 작은 분자량을 가지는 고분자가 얻어졌으며 넓은 분자량 분포와 낮은 수율이 얻어지며 이것은 중압반응 도중에 분자 내에서 상호반응을 일으킴을 보여준다.

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$^{13}C$ NMR Studies of the Chelate Ring Opening-Closing Process in (Nitrilotriacetato)vanadate(V) dioxovandate(V) Ion

  • Lee, Man-Ho;Schaumburg, Kjeld
    • Bulletin of the Korean Chemical Society
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    • v.11 no.5
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    • pp.399-402
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    • 1990
  • Activation parameters of the exchange between two types of glycinate groups in (nitrilotriacetato)dioxovanadate(V) ion, $[VO_2(NTA)]^{2-}$, have been determined as the results of $^{13}C$ NMR measurements over a range of temperatures between 277 and 306$^{\circ}K$. The exchange mechanism is proposed on the basis of the chelate ring opening-closing process, assuming rupture of the metal-oxygen (glycinate) bond trans to V = O bond to give a five-coordinated intermediate.

Characteristics of Ring-Opening Isomerization Polymerization of [4.3.0] Cyclic Pseudoureas ([4.3.0] 환상 유사 우레아의 이성화 개환중합과 특성평가)

  • Lee, Chan-Woo;Chung, Jin-Do
    • Polymer(Korea)
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    • v.35 no.4
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    • pp.308-313
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    • 2011
  • The ring-opening isomerization polymerization behavior of 2,5,6,7-tetrahydro-3H-imidazo[2,1-b] [1,3] oxazine(TII) has been studied under various conditions. The present study aimed at improving the low polymerizability of the above monomer (six-membered ring) up to a level comparable to that of 2,5,6-tetrahydroimidazo[2,1-b] [l,3] oxazole(TIO) (five-membered ring). The optimum result could be observed when methyl trifluoromethanesulfonate(MeOTf) and nitrobenzene were used as an initiator and a solvent in the polymerization at $60^{\circ}C$ for 24 h. Polymers were confirmed by$^1H$ NMR과$^{13}C$ NMR, and m measurements. The molecular weight obtained by gel permeation chromatography (GPC) corresponded to the molecular weight theoretically calculated from the feed ratio. The melting temperature ($T_m$) of TII was conspicuously different from that of TIO, because of the difference in the alkyl group.