羟基磷灰石包覆γ-Fe_2O_3担载氧化钼:一种新型磁性可回收的烯烃环氧化多相催化剂(英文)

Molybdenum Oxide Supported on Hydroxyapatite-Encapsulated γ-Fe_2O_3:A Novel Magnetically Recyclable Catalyst for Olefin Epoxidation

制备了羟基磷灰石(HAP)包覆纳米γ-Fe2O3颗粒复合材料(HAP-γ-Fe2O3),并进一步采用浸渍法担载氧化钼(MoOx/HAP-γ-Fe2O3).高分辨透射电镜结果表明,γ-Fe2O3纳米颗粒被包覆于HAP当中,平均粒径为1～3nm.所制备催化剂对以叔丁基过氧化氢为氧化剂的烯烃环氧化反应显示了良好的催化活性.此外,催化剂的可磁力分离特性为反应后催化剂的分离回收提供了一种方便、快捷的途径.催化剂可重复使用至少5次以上而没有显著的活性下降.

Hydroxyapatite-encapsulated magnetic γ-Fe2O3（HAP-γ-Fe2O3） was synthesized and used as catalyst support. Molybdenum oxide nanoparticles were supported on HAP-γ-Fe2O3 by incipient wetness impregnation（MoOx/HAP-γ-Fe2O3） . High-resolution transmission elec-tron microscopy characterization demonstrated the formation of γ-Fe2O3 nanocrystallites with a mean diameter of 1–3 nm within the HAP matrix. The molybdenum oxide dispersed on the surface of HAP-γ-Fe2O3 showed good catalytic activities for the epoxidation of various olefins with tert-butyl hydroperoxide as oxidant. The magnetism of MoOx/HAP-γ-Fe2O3 provided a convenient route for the separation of the catalyst from the reaction mixture by a magnet. The catalyst was recycled at least five times without appreciable loss of catalytic activity.