Intramolecularly dinuclear magnesium complex catalyzed copolymerization of cyclohexene oxide with CO2 under ambient CO2 pressure: Kinetics and mechanism

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	Intramolecularly dinuclear magnesium complex catalyzed copolymerization of cyclohexene oxide with CO2 under ambient CO2 pressure: Kinetics and mechanism
	Xiao YL(肖友利) ; Wang Z(王正) ; Ding KL(丁奎岭)
刊名	Macromolecules
	2006
卷号	39 期号:1 页码:128-137
ISSN号	0024-9297
其他题名	分子内双核镁络合物催化的二氧化碳与氧化环己烯的常压共聚合反应: 动力学和机理研究
通讯作者	丁奎岭
英文摘要	The intramolecularly dinuclear magnesium complexes generated in situ from the reaction of multidentate semi-azacrown ether ligands with n-Bu2Mg followed by treatment with alcohol additive were found to be efficient catalysts for the copolymerization of CO2 and cyclohexene oxide (CHO), affording the completely alternating poly(cyclohexene carbonate) (PCHC) under extremely mild conditions (1 atm pressure of CO2, temperatures ranging from 20 to 60 degrees C). Ligand substituent effects were observed to dramatically influence both the activity and the chemoselectivity of the catalysis, exemplifying the fine-tunability of this type of ligands. With regard to the mechanistic studies, end-group analysis of the copolymer by MALDI-TOF mass spectroscopy revealed the predominance of the butoxy-initiated CO2/CHO copolymerization process. The butoxy-containing catalytically active species in the present system was proposed to possess a dinuclear structure similar to an isolated model Mg complex which was characterized by X-ray crystal structural analysis. Rate studies performed on the copolymerization using the in situ prepared catalyst (molar ratio of 5a:n-Bu2Mg:n-BuOH = 1:2:0.4) at 60 degrees C demonstrate a zero-order dependence on CO2 Pressure and approximately first-order dependence on CHO and the catalyst concentration. Furthermore, the relative propensity of polycarbonate vs cyclic carbonate formation in the present system was evaluated by a comparative kinetic study of the temperature effect using the in situ IR technique. On the basis of these findings, a plausible bimetallic mechanism was tentatively proposed for the present reaction system.
学科主题	金属有机化学
收录类别	SCI
原文出处	http://dx.doi.org/10.1021/ma051859+
语种	英语
WOS记录号	WOS:000234500100023
公开日期	2013-02-22
内容类型	期刊论文
源URL	[http://202.127.28.38/handle/331003/17829]
专题	上海有机化学研究所_金属有机化学国家重点实验室
推荐引用方式 GB/T 7714	Xiao YL,Wang Z,Ding KL. Intramolecularly dinuclear magnesium complex catalyzed copolymerization of cyclohexene oxide with CO2 under ambient CO2 pressure: Kinetics and mechanism[J]. Macromolecules,2006,39(1):128-137.
APA	肖友利,王正,&丁奎岭.(2006).Intramolecularly dinuclear magnesium complex catalyzed copolymerization of cyclohexene oxide with CO2 under ambient CO2 pressure: Kinetics and mechanism.Macromolecules,39(1),128-137.
MLA	肖友利,et al."Intramolecularly dinuclear magnesium complex catalyzed copolymerization of cyclohexene oxide with CO2 under ambient CO2 pressure: Kinetics and mechanism".Macromolecules 39.1(2006):128-137.