이산화탄소/에폭사이드 공중합 촉매 개발
Development of Catalysts for CO₂/Epoxide Copolymer
- 주제(키워드) 공중합 촉매 , 이산화탄소 , 에폭사이드 , CO₂ , Epoxide Copolymer
- 주제(KDC) 570
- 주제(DDC) 660
- 발행기관 아주대학교 일반대학원
- 지도교수 이분열
- 발행년도 2007
- 학위수여년월 2007. 2
- 학위명 석사
- 학과 및 전공 일반대학원 분자과학기술학과
- 본문언어 영어
초록/요약
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.
more목차
Chapter 1. Bimetallic Fluorine-Substituted Anilido-Aldimine Zinc Complexes for CO₂/(Cyclohexene Oxide) Copolymerization = 1
1-1. Introduction = 2
1-2. Results and Discussion = 4
1-3. Summary = 13
1-4. Experimental Section = 14
1-5. Figures = 31
1-6. References = 44
Chapter 2. Coupling Reaction of CO₂ with Epoxides by Binary Catalytic System of Lewis acids and Onium Salts = 47
2-1. Introduction = 48
2-2. Results and Discussion = 49
2-3. Conclusion = 53
2-4. Experimental Section = 54
2-5. Figures = 55
2-6. References = 59
