Fei Jingyuan, Sun Lixian, Zhou Cuifeng, Ling Huajuan, Yan Feng, Zhong Xia, Lu Yuxiang, Shi Jeffrey, Huang Jun, Liu Zongwen
School of Chemical and Bimolecular Engineering, The University of Sydney, Sydney, NSW, 2006, Australia.
School of Materials Science and Engineering, Guilin University of Electronic Technology, Guilin, 541004, China.
Nanoscale Res Lett. 2017 Dec;12(1):23. doi: 10.1186/s11671-016-1777-y. Epub 2017 Jan 6.
The liquid phase oxidation of benzyl alcohol is an important reaction for generating benzaldehyde and benzoic acid that are largely required in the perfumery and pharmaceutical industries. The current production systems suffer from either low conversion or over oxidation. From the viewpoint of economy efficiency and environmental demand, we are aiming to develop new high-performance and cost-effective catalysts based on manganese oxides that can allow the green aerobic oxidation of benzyl alcohol under mild conditions. It was found that the composition of the precursors has significant influence on the structure formation and surface property of the manganese oxide nanoparticles. In addition, the crystallinity of the resulting manganese nanoparticles was gradually improved upon increasing the calcination temperature; however, the specific surface area decreased obviously due to pore structure damage at higher calcination temperature. The sample calcined at the optimal temperature of 600 °C from the precursors without porogen was a MnO-rich material with a small amount of MnO, which could generate a significant amount of [Formula: see text] species on the surface that contributed to the high catalytic activity in the oxidation. Adding porogen with precursors during the synthesis, the obtained catalysts were mainly MnO crystalline, which showed relatively low activity in the oxidation. All prepared samples showed high selectivity for benzaldehyde and benzoic acid. The obtained catalysts are comparable to the commercial OMS-2 catalyst. The synthesis-structure-catalysis interaction has been addressed, which will help for the design of new high-performance selective oxidation catalysts.
苄醇的液相氧化是生成香料和制药工业中大量需求的苯甲醛和苯甲酸的重要反应。目前的生产系统存在转化率低或过度氧化的问题。从经济效率和环境需求的角度来看，我们旨在开发基于锰氧化物的新型高性能且具有成本效益的催化剂，该催化剂能够在温和条件下实现苄醇的绿色有氧氧化。研究发现，前驱体的组成对锰氧化物纳米颗粒的结构形成和表面性质有显著影响。此外，随着煅烧温度的升高，所得锰纳米颗粒的结晶度逐渐提高；然而，由于在较高煅烧温度下孔结构受损，比表面积明显降低。由无致孔剂的前驱体在600℃最佳温度下煅烧得到的样品是一种富含MnO且含有少量MnO₂的材料，其表面能够产生大量有助于氧化反应中高催化活性的[公式：见原文]物种。在合成过程中向前驱体中添加致孔剂，得到的催化剂主要是MnO晶体，其在氧化反应中表现出相对较低的活性。所有制备的样品对苯甲醛和苯甲酸均表现出高选择性。所获得的催化剂与商业OMS - 2催化剂相当。本文探讨了合成 - 结构 - 催化之间的相互作用，这将有助于设计新型高性能选择性氧化催化剂。
