Centro de Química Estrutural, Complexo I, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal.
Centro de Química e Bioquímica, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal.
Molecules. 2020 Feb 8;25(3):740. doi: 10.3390/molecules25030740.
Iron-containing particulate catalysts of 0.1-1 µm size were prepared by wet and ball-milling procedures from common salts and characterized by FTIR, TGA, UV-Vis, PXRD, FEG-SEM, and XPS analyses. It was found that when the wet method was used, semi-spherical magnetic nanoparticles were formed, whereas the mechanochemical method resulted in the formation of nonmagnetic microscale needles and rectangles. Catalytic activity of the prepared materials in the oxidation of 1-phenylethanol to acetophenone was assessed under conventional heating, microwave (MW) irradiation, ultrasound (US), and oscillating magnetic field of high frequency (induction heating). In general, the catalysts obtained by wet methods exhibit lower activities, whereas the materials prepared by ball milling afford better acetophenone yields (up to 83%). A significant increase in yield (up to 4 times) was observed under the induction heating if compared to conventional heating. The study demonstrated that MW, US irradiations, and induction heating may have great potential as alternative ways to activate the catalytic system for alcohol oxidation. The possibility of the synthesized material to be magnetically recoverable has been also verified.
0.1-1 µm 尺寸的含铁颗粒催化剂通过湿化学法和球磨法由普通盐制备，并通过 FTIR、TGA、UV-Vis、PXRD、FEG-SEM 和 XPS 分析进行了表征。结果表明，当使用湿法时，形成了半球形磁性纳米颗粒，而机械化学法导致形成非磁性微尺度针和矩形。在常规加热、微波 (MW) 辐射、超声 (US) 和高频振荡磁场 (感应加热) 下，评估了所制备材料在 1-苯乙醇氧化为苯乙酮中的催化活性。一般来说，通过湿法获得的催化剂活性较低，而通过球磨法制备的材料提供了更好的苯乙酮产率（高达 83%）。与常规加热相比，感应加热时产率显著增加（高达 4 倍）。该研究表明，MW、US 辐射和感应加热可能具有作为激活醇氧化催化体系的替代方法的巨大潜力。还验证了合成材料具有磁性可回收性的可能性。
