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이산화탄소/에폭사이드 공중합 촉매 개발
- Author(s)
- 복태기
- Advisor
- 이분열
- Department
- 일반대학원 분자과학기술학과
- Publisher
- The Graduate School, Ajou University
- Publication Year
- 2007-02
- Language
- eng
- Alternative Abstract
- 1. Regioselective nucleophilic aromatic substitution of an ortho-fluorine occurs to afford fluorine-substituted ortho-phenylene bridged bis(anilido-aldimine) compounds, ortho-C_(6)H₄{(C_(6)H₂R₂)N=CH-C_(6)F₄-(H)N(C_(6)H₃R'₂)}₂ when Li(H)N-C_(6)H₃R'₂ (R' = iPr, Et, Me) is reacted with ortho-C_(6)H₄{(C_(6)H₂R₂)N=CH-C_(6)F_(5)}₂ (R = iPr, Et, Me) in nonpolar solvent such as diethyl ether or toluene. Successive additions of Me2Zn and SO₂ gas to the bis(anilidoaldimine) compounds afford quantitatively dinuclear m-methylsulfinato zinc complexes, ortho-C_(6)H₄{[(C_(6)H₂R₂)N=CH-C_(6)F₄-N(C_(6)H₃R'2)-k²N,N]Zn(m-OS(O)Me)}₂ (R = iPr, R' = iPr, 3a; R = iPr, R' = Me, 3c; R = Et, R' = iPr, 3d; R = Et, R' = Et, 3e; R = Et, R' = Me, 3f; R = Me, R' = iPr, 3g; R = Me, R' = Et, 3h; R = Me, R' = Me, 3i). Molecular structure of 3c was confirmed by the X-ray crystallography. The fluorine-substituted complexes 3a-3i show significant higher TOF (turnover frequency) than the unfluorinated analogues for CO₂/(cyclohexene oxide) copolymerization. The TOF is highly sensitive to the substituents, R and R' and the highest TOF (1720 h^(-1)) is obtained with 3g (R = Me, R' = iPr). The complex 3g is less sensitive to the residual protic impurities present in the monomers and shows activity at such a low catalyst concentration as [Zn]/[cyclohexene oxide] = 1:50,000, at which the unfluorinated analogue is completely inactive. By realizing the activity at such an extremely low [Zn]/[cyclohexeneoxide] ratio, high TON (turnover number) up to 10100 is achieved. High molecular-weight polymers (M_(n), 100,000 - 200,000) are obtained with rather broad molecular weight distribution (M_(w)/M_(n), 1.3-2.5). The obtained polymers are not perfectly alternating and variable carbonate linkages (65-85 %) are observed depending on the N-aryl ortho-substituents, R and R'. 2. Various off-the-shelf Lewis acids in conjunction with various onium salts are screened for coupling reaction of CO₂ with epoxides. Among the tested ones, VCl₃/n-Bu₄NOAc, VCl₃/(n-Bu₄NCl or PPNCl), FeCl₃/n-Bu₄NOAc, and AlCl₃/n-Bu₄NOAc are proved to be highly active. Propylene oxide, epichlorohydrin, styrene oxide, and cyclohexene oxide can be converted over 90% yields to the corresponding cyclic carbonates without the use of organic solvents under mild conditions by 0.1-1.0 mol% catalyst charge.
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- Graduate School of Ajou University > Department of Molecular Science and Technology > 3. Theses(Master)
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