期刊
JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL
卷 363, 期 -, 页码 343-353出版社
ELSEVIER
DOI: 10.1016/j.molcata.2012.07.010
关键词
Sulfonato-(salen)Mn(III); Immobilization; Epoxidation; Sulfoxidation; Recycling
资金
- Fundamental Research Funds for the Central University of China
This article reports our study on asymmetric epoxidation of unfunctionalized alkenes and asymmetric oxidation of sulfides catalyzed by a new triply immobilized (salen)Mn(III) system, when commercial sodium hypochlorite and hydrogen peroxide were loaded as terminal oxidant, respectively. A chiral sulfonato(salen)Mn(III) complex was grafted onto a novel polysiloxane, then axially coordinated by 3-aminopropyl functionalized silica gel (40-63 mu m, 1 mmol g(-1) NH2 loading) as a secondary anchoring mode, and eventually dispersed into ionic liquid BMImX (BMIm(+) = 1-n-butyl-3-methylimidazolium: X- = PF6-, NO3-) for purpose of catalyst recycling. Catalysts were fully characterized by H-1 NMR, FT-IR, molar conductivity, elemental analysis, nitrogen adsorption, aqueous particle size and zeta potential analysis, along with XRD. Interestingly, lateral immobilization led to a novel catalyst structure featuring parallel stacking of one-dimensional planers, whereas the lateral together with axial immobilization made supported complex nano-sized crystallite particles (diameter 24.2 nm). After stepwise screening, doubly-immobilized catalyst and BMImBF(4), in combination, showed best enantiomeric excess (e.e.) values and most stable recycling behavior in two kinds of catalysis, but generally sulfoxidation had better turnover frequencies than epoxidation reaction. (C) 2012 Elsevier B.V. All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据