Salen-Co配合物在核-壳结构的Silica上的接枝及催化性能的研究  

Chemically Grafting and Catalytic Performances of Salen-Co Complex onto Silica and Core-shell Silica for Epoxidation of Alkene with Oxygen in the Presence of Isobutyraldehyde

作　　者：周建波[1] 伏再辉[1] 曾明[1] 曾小军[1] 崔小莹[1] 

机构地区：[1]长沙医学院,湖南长沙410219

出　　处：《精细化工中间体》2009年第6期63-68,共6页Fine Chemical Intermediates

基　　金：国家自然科学基金资助项目(20573035)

摘　　要：分别以球状纳米silica和悬浮聚合法制备的核-壳型silica-苯乙烯与丙烯酸甲酯共聚物杂化体为载体,采用化学接枝方法,制备了Salen-Co配合物固载型催化剂。采用FT-IR、TG-DTA和TEM对这些催化剂进行了表征。结果表明:核-壳型催化剂其壳层性质可通过改变两个单体的比例来调变,随单体丙烯酸甲酯比例的增加,壳层由聚苯乙烯占优逐渐过渡到以聚丙烯酸甲酯为主,接枝的钴配合物负载量也相应增加。在以分子氧作氧化剂,异丁醛作牺牲醛,催化环己烯氧化反应中,核-壳型催化剂在反应速度和环氧选择性上均优于silica型催化剂;相反,在反式二苯乙烯氧化反应中,则是后者明显优于前者。造成这种差别的原因很可能与壳层表面聚合物与两个反应底物的亲和力差异显著有关。By means of chemically grafting method, Salen-Co complex has been successfully bonded onto the surfaces of nano-silica and inorganic-organic hybrid carriers which consist of nano-silica core and styrene and methyl acrylate copolymers shell. The prepared catalysts were characterized by FT-IR, TG-DTA and TEM. The characterization results indicated that the shell layer properties of the core-shell carriers could be adjusted by varying the ratio of the two monomer, the shell with the majority of poly-styrene was gradually transmitted to be characteristic of the poly methyl acrylate with increasing methyl acrylate. In catalyzing the epoxidation of cyclohexene, the Co complexes with the core-shell carriers showed a higher catalytic activity than with nanosilica carriers. This is mainly due to the former has a better affinity to the substrate than the latter. However, in catalyzing the epoxidation of E-stilbene, the reversed results were obtained. This is likely because of affinity differences between the catalysts and the substvates.

关 键 词：纳米二氧化硅 核-壳结构 Salen—Co 环氧化 

分 类 号：TQ252.5[化学工程—有机化工]