Synthesis and characterization of Co(II) salen functionalized MCM-41-type hybrid mesoporous silicas and their applications in catalysis for styrene oxidation with H2O2
Synthesis and characterization of Co(II) salen functionalized MCM-41-type hybrid mesoporous silicas and their applications in catalysis for styrene oxidation with H2O2
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DOI：
10.1016/j.micromeso.2005.07.016
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发表时间：
2005-11
影响因子：
5.2
通讯作者：
Yan Luo;Jun Lin
中科院分区：
文献类型：
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作者：
Yan Luo;Jun Lin
席夫碱功能化MCM-41型杂化介孔二氧化硅（MCM-41-SalenH）是通过原硅酸四乙酯（TEOS）和水杨醛改性（3-氨丙基）三乙氧基硅烷（SalenHSi）前体在十六烷基三甲基溴化铵（CTAB）存在下共缩合，然后通过表面活性剂萃取合成的。进行印迹技术以恢复酸提取过程中破坏的水杨醛亚胺基团。通过傅里叶变换红外（FT-IR）光谱证实希夫碱的回收。 29Si的固态CP-MAS NMR光谱(29Si CP-MAS NMR)显示出高度稠合的硅氧烷网络。共缩合和印迹技术生产出具有均匀介孔通道、高比表面积（>1200m2g−1）和大孔体积（>1.25cm3g−1）的MCM-41-SalenH杂化介孔二氧化硅。通过配体交换反应将Co2+引入杂化材料中可以获得固体氧化催化剂。与相应的均相催化剂相比，该固体催化剂在温和条件下表现出更高的 H2O2 苯乙烯液相氧化活性和对活性 Co2+ 浸出的稳定性。
Schiff base functionalized MCM-41-type hybrid mesoporous silica (MCM-41-SalenH) was synthesized by co-condensation of tetraethyl orthosilicate (TEOS) and the precursor of salicylaldehyde modified (3-aminopropyl)triethoxysilane (SalenHSi) in the presence of cetyltrimethylammonium bromide (CTAB) followed by surfactant extraction. Imprinting technique was carried out to recover the salicylaldimine groups disrupted during the acid extraction process. The recovery of the Schiff base was confirmed by Fourier transform infrared (FT-IR) spectroscopy. Solid state CP-MAS NMR spectroscopy of29Si (29Si CP-MAS NMR) showed a highly condensed siloxane network. The co-condensation and imprinting technique produced MCM-41-SalenH hybrid mesoporous silica with uniform mesoscale channels, high specific surface areas (>1200m2g−1) and large pore volumes (>1.25cm3g−1). Solid oxidation catalysts can be obtained by introducing Co2+into the hybrid materials via a ligand exchange reaction. The solid catalysts showed higher activity for the liquid-phase oxidation of styrene with H2O2under mild condition and stability against leaching of active Co2+compared with the corresponding homogeneous catalysts.