• 제목/요약/키워드: Olefins

검색결과 139건 처리시간 0.022초

A Mechanistic Study on the Nucleophilic Addition Reactions of Benzylamines to the Activated Olefins

  • Oh, Hyuck-Keun
    • Bulletin of the Korean Chemical Society
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    • 제29권6호
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    • pp.1195-1198
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    • 2008
  • Kinetic studies of the additions of benzylamines to a noncyclic dicarbonyl group activated olefin, methyl $\alpha$-acetyl-$\beta$ -phenylacrylates (MAP), in acetonitrile at 30.0 ${^{\circ}C}$ are reported. The rates are lower than those for the cyclic dicarbonyl group activated olefins. The addition occurs in a single step with concurrent formation of the $C_\alpha$ -N and $C_\beta$ -H bonds through a four-center hydrogen bonded transition state. The kinetic isotope effects ($k_H/k_D$ > 1.0) measured with deuterated benzylamines ($XC_6H_4CH_2ND_2$) increase with a stronger electron acceptor substituent ($\delta\sigma$ X > 0) which is the same trend as those found for other dicarbonyl group activated series (1-4). The sign and magnitude of the cross-interaction constant, ρXY, is comparable to those for the normal bond formation processes in the $S_N2$ and addition reactions. The relatively low ${\Delta}H^\neq$ and large negative ${\Delta}S^\neq$ values are also consistent with the mechanism proposed.

헤테로폴리산 촉매에 의한 탄화수소로의 메탄올 전환반응(I) (Conversion of Methanol to Hydrocarbons over Heteropoly Acids(I))

  • 홍성수;이호인
    • 공업화학
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    • 제2권4호
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    • pp.363-371
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    • 1991
  • 탄화수소로의 메탄올 전환반응에 대한 헤테로폴리산 화합물의 역할과 적용성에 관하여 연구하였다. 탄화수소의 수율과 저급 올레핀의 선택도를 높히기 위하여 반응온도, 메탄올 분압 및 접촉시간 등 반응조건의 영향과 촉매의 이온교환 효과를 조사하였다. 그들의 산의 세기는 치환된 금속이온의 종류에 따라 달라졌고, 탄화수소의 수율과 프로판에 대한 프로필렌의 선택도는 상대 금속이온의 전기음성도와 밀접한 관계를 보여주었다. 다른 헤테로폴리산 화합물과는 달리 암모늄염은 상당히 높은 촉매활성과 저급 올레핀에 대한 파라핀의 높은 선택도를 보여 주었다.

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무정형 알파-올레핀 고분자/무정형 폴리아미드 블렌드의 반응 상용화 (Reactive Compatibilization of Amorphous Poly-${\alpha}$-olefins/Amorphous Polyamide Blends)

  • 윤덕우;최미주;황규희;김건석;이광희
    • 폴리머
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    • 제33권5호
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    • pp.490-495
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    • 2009
  • Maleated 폴리프로필렌과 에틸렌-글리시딜 메타크릴레이트-메틸 아크릴레이트의 공중합체를 반응성 상용화제로 사용하여 무정형 알파올레핀 고분자/무정형 폴리아미드 블렌드의 반응 상용화를 시도하였다. 무정형 폴리아미드와 상용화제간의 그래프트 반응 정도는 FT-IR, SEM 및 rheometer로 조사하였다. 반응상용화에 따른 블렌드의 기계적 물성 변화 및 하이드로카본 형태의 점착부여수지를 첨가한 블렌드의 접착강도는 만능시험기로 조사하였다.

Preparation of Copper Nanoparticles in Cellulose Acetate Polymer and the Reaction Chemistry of Copper Complexes in the Polymer

  • Shim, Il-Wun;Noh, Won-Tae;Kwon, Ji-Woon;Jo, Jung-Young;Kim, Kyung-Soo;Kang, Dong-Hee
    • Bulletin of the Korean Chemical Society
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    • 제23권4호
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    • pp.563-566
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    • 2002
  • Copper complexes have been directly incorporated into cellulose acetate (CA) and the resulting light blue colored homogeneous films of 5-20 wt.% copper acetate complex concentrations are found to be thermally stable up to 200 $^{\circ}C$. The reaction chem istry of Cu in CA has been investigated by reacting them with small gas molecules such as CO, H2, D2, O2, NO, and olefins in the temperature range of 25-160 $^{\circ}C$, and various Cu-hydride, -carbonyl, -nitrosyl, and olefin species coordinated to Cu sites in CA are characterized by IR and UV/Vis spectroscopic study. The reduction of Cu(II) complexes by reacting with H2 gas at the described conditions results in the formation of Cu2O and copper metal nanoparticles in CA, and their sizes in 30-120 nm range are found to be controlled by adjusting metal complex concentration in CA and/or the reduction reaction conditions. These small copper metal particles show various catalytic reactivity in hydrogenation of olefins and CH3CN; CO oxidation; and NO reduction reactions under relatively mild conditions.