纳米二氧化硅催化剂催化Michael反应研究.doc

文档介绍：
纳米二氧化硅催化剂催化 Michael 反应研究
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韩素珍,苏向阳,钟琳**
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(四川大学化学工程学院,成都 610065)
摘要:脱水活化后的纳米二氧化硅颗粒能有效催化 Michael 加成反应,研究了不同温度及六
甲基二硅氮烷(HMDS)处理改变二氧化硅表面性质后催化剂的催化性能改变。结果表明,随
着热处理温度的升高,二氧化硅催化活性降低;HMDS 能够覆盖其表面的单独硅羟基,从而
降低二氧化硅催化活性。研究表明,二氧化硅表面的硅羟基是催化活性中心,催化活性与硅
羟基浓度和类型密切相关。不同溶剂对反应活性影响明显,DMF 为反应的最佳溶剂,反应收
率最高可达 71%。
关键词:二氧化硅;硅羟塖;Michael 加成反应
中图分类号:
Nano-Silica Catalyst for Michael Addition Reaction
HAN Suzhen, SU Xiangyang, ZHONG Lin
(College of Chemical Engineering, Sichuan University,Chengdu 610065)
Abstract: Nano-silica activated by removing the surface absorbed water can catalyze Michael addition
reaction effectively. After changing its surface properties by thermal and hexamethyldisilazane (HMDS)
treatments, the performance of the catalyst for the reaction was investigated. The results show that
catalytic activity is reduced as treatment temperature rises. HMDS can cover isolated silanols, which
leads a decrease of catalytic activity. It is suggested that the surface silanols are catalytic active center.
The catalytic activity is closely related to the silanol concentration and types. It was also found that
solvent effect has great influence on the reactivity. DMF is the optimum solvent for the reaction and a
yield of up to 71 % can be achieved.
Key words: Silica;Silanol;Michael addition reaction
0 引言
Michael 加成反应是一种亲核试剂对α,β-不饱和羰基化合物双键的共轭加