| 丁浩,高保娇,程伟.聚合物固载的新型手性SalenMn(Ⅲ)配合物在苯乙烯不对称环氧化反应中催化性能的研究[J].分子催化,2013,(2):115-123 |
| 聚合物固载的新型手性SalenMn(Ⅲ)配合物在苯乙烯不对称环氧化反应中催化性能的研究 |
| Studies on Catalytic Properties of New Polymer-Immobilized Chiral Salen Mn(Ⅲ) Complex in Catalytic Asymmetric Epoxidation of Styrene |
| 投稿时间：2013-01-11 修订日期：2013-03-15 |
| DOI： |
| 中文关键词: 手性SalenMn(Ⅲ)配合物 固载化 苯乙烯 不对称环氧化 |
| 英文关键词:Chiral Mn(Ⅲ)-Salen Complex Immobilization Styrene Asymmetric epoxidation |
| 基金项目:山西省自然科学基金(2010021008-4) |
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| 中文摘要: |
| 以交联聚苯乙烯(CPS)微球为载体, 通过高分子反应和配位反应, 简捷高效地制得一种新型固载化手性Salen金属配合物催化剂Mn(Ⅲ)Salen-CPS.本研究以间氯过氧苯甲酸(m-CPBA)为氧化剂、以N-甲基吗啉-N-氧化物(NMO)为轴向配体, 将该非均相手性SalenMn(Ⅲ)催化剂用于苯乙烯的不对称环氧化反应,深入考察了其催化性能,较详细地研究了主要因素对苯乙烯的不对称环氧化反应的影响, 并从微观机理上进行了分析讨论. 实验结果表明, 在苯乙烯的不对称环氧化反应中, 微球Mn(Ⅲ)Salen-CPS具有高的催化活性与良好的的对映体选择性, 20℃下反应8h, 苯乙烯的转化率可达85%; 0℃下反应2h, 产物的ee值可达58%. Salen配基中手性二胺的不对称环境、轴向配体NMO的加入、反应温度与时间、溶剂的极性等因素对苯乙烯的不对称环氧化反应都有很大的影响. 轴向配体NMO的加入使苯乙烯转化率与产物的ee值均可得到提高; 低温有利于产物的ee值的提高, 苯乙烯的不对称环氧化反应适宜的反应温度为0℃; 使用极性弱的溶剂, 有利于催化剂的对映体选择性; 当反应进行到一定程度, 产物的ee值会出现最高值, 其后ee值会随时间延长呈现下降趋势, 在不同的反应条件下, ee值出现最大值的时间不同. |
| 英文摘要: |
| By using crosslinked polysltyrene (CPS) microshpheres as support, a new immobilized chiral Salen Mn(Ⅲ) complex catalyst Mn(Ⅲ)Salen-CPS was simply and efficiently prepared via two polymer reactions and a coordination-chelating reaction. In this work, this solid catalyst was used in the asymmetric epoxidation of styrene with m-chloroperoxybenzoic acid (m-CPBA) as oxidant and N-methyl morpholine-N-oxide (NMO) as axial base, ands its catalytic properties were examined in depth. The effects of main factors on the asymmetric epoxidation reaction of styrene were researched detailedly, and the relevant rules were analysed and discussed from the view of micro-mechanism. The experimental results show that in the asymmetric epoxidation reaction of styrene, Mn(Ⅲ)Salen-CPS microspheres have high catalytic activity and excellent enantioselectivity of the epoxide. At the temperature of 20℃ in 8h, the conversion of styrene is closed to 85%, and at the temperature of 0℃ in 2h, the ee value of the epoxide can reach 58%. Both the asymmetric environment of the diamine and the addition of the axial base are beneficial to the obvious enhancement of the enantioselectivity of the epoxide. the reaction time, temperature, the polarity of the solvent and the used amont effect the asymmetric epoxidation reaction of styrene greatly. The lower temperature is beneficial to the enhancement of enantioselectivity of the epoxide, and for this present system, the suitable temperature of the asymmetric epoxidation of styrene is zero centigrade. Using the solvent with weak polarity is advantageous to the enantioselectivity of the epoxide. The ee value of the epoxide will exhibit a maximum value as the reaction is carried out to a certain degree, and then the ee value will decrease with the increase of the reaction time. Furthermore, the time at which the ee value exhibits a maximum value is different under the different reaction conditions. |
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