Superparamagnetic magnesium ferrite nanoparticles: a magnetically reusable and clean heterogeneous catalyst

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• 作者：Mehdi Sheykhan^a ; ^&dagger ; ; Hossein Mohammadnejad^b ; Jafar Akbari^a ; ^&dagger ; ; Akbar Heydari^a ; ^{akbar.heydari@gmx.de}
• 关键词：Magnesium ferrite ; Magnetic recovery ; 伪-Hydroxyphosphonate ; 伪-Aminophosphonate ; Green catalysis
• 刊名：Tetrahedron Letters
• 出版年：2012
• 期刊代码：109_00404039
• 类别：ch
• 出版时间：13 June, 2012
• 卷：53
• 期：24
• 页码：2959-2964
• 文件大小：1946 K

摘要

A highly efficient magnetically recoverable nano-catalyst was fabricated. The material synthesized has been fully characterized by vibrating sample magnetometry (VSM), X-ray powder diffraction, scanning and transmission electron microscopy, FT-IR, and the Brunauer-Emmett-Teller (BET) isotherm method. An investigation of its catalytic activity showed it to be a unique heterogeneous Lewis acid catalyst for the synthesis of 伪-hydroxy and 伪-aminophosphonates, giving a total turnover number 猢?50 for five consecutive runs. The catalyst is superparamagnetic having a 鈥榤agnetization (left behind after an external magnetic field is removed)鈥?to 鈥榤agnetic saturation鈥?ratio of about 0.0008, and thus could be easily separated by the use of an external magnetic field and was not agglomerated by exposure to magnetic fields.