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고활성의 이산화탄소-에폭사이드 고분자 중합 촉매에 관한 구조 해석
- Author(s)
- 나성재
- Advisor
- 이분열
- Department
- 일반대학원 분자과학기술학과
- Publisher
- The Graduate School, Ajou University
- Publication Year
- 2010-02
- Language
- eng
- Keyword
- 고활성; 이산화탄소-에폭사이드; 고분자; 종합 촉매; 구조 해석
- Alternative Abstract
- 1. Salen-type ligands comprised of ethylenediamine or 1,2-cyclohexenediamine, along with an salicylaldehyde bearing a methyl substituent on its 3-position and -[CR(CH2CH2CH2N+Bu3)2] (R = H or Me) on its 5-position, unexpectedly afford cobalt(III) complexes with uncoordinated imines. In these complexes, two Salen-phenoxys and two 2,4-dinitrophenolates (DNPs), which counter the quaternary ammonium cations, coordinate persistently with cobalt while two other DNPs are fluxional between a coordinating and an uncoordinated state in THF at room temperature. The complexes of this binding mode show excellent activities in CO2/propylene oxide copolymerization (TOF, 83000-13000 h-1), but with some fluctuation in induction times (1 - 10 hours) depending on how dry the system is. The induction time is shortened (< 1.0 h) and activity is increased ~1.5 times upon replacement of the two fluxional DNPs with 2,4-dinitrophenol-2,4-dinitrophenolate homoconjugation ([DNP...H...DNP]-). Imposing steric congestion by either replacing the methyl substituent on salicylaldehyde with tert-butyl or employing H2NCMe2CMe2NH2 instead of ethylenediamine or 1,2-cyclohexenediamine results in conventional imine-coordinating complexes, which show lower activities than imine-not-coordinating complexes. Anion exchange of BF4- occurs by stirring a cobalt(III) complex of Salen-type ligand tethered by four quaternary ammonium BF4- salts over a slurry of NaX in CH2Cl2, affording a complex containing four X's per cobalt (X = 2,4,5-trichlorophenolate, X = 4-nitrophenolate, X = 2,4-dichlorophenolate). The 1H and 13C NMR spectra are in agreement with an unusual imine uncoordinated structure. 2. Regioselective partial hydrogenation of tricyclopentadiene (TCPD) is achieved with a high TON (turnover number) up to 10000 by employing a N-heterocyclic carbene palladium complex as a catalyst. Copolymerization of ethylene and the partial hydrogenated product, dihydrotricyclopentadiene (HTCPD) is realized using a catalytic system of [8-(？？5-C5Me4)-2-Me(C9H8N)-？？N]TiMe2 (C9H10NH = 1,2,3,4-tetrahydroquinoline) activated with (Ph3C)+[B(C6F5)4]-. The copolymer is unambiguously characterized through analysis of one- and two-dimensional NMR spectra. The monomer reactivity ratios, rethylene and rHTCPC, determined through the Fineman-Ross plot, are 2.8 and 0.025, indicating successive insertion of two HTCPD is negligibly allowed. A nearly alternating copolymer of HTCPD content of 45 mol% is obtained with a satisfactory activity (4.7 ？e106 g/molTi？？h) whose Tg is 177oC, significantly higher than those of other cycloolefin-derived copolymer at the same cycloolefin content.
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- Graduate School of Ajou University > Department of Molecular Science and Technology > 3. Theses(Master)
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