Water-tolerant heteropolyacid on magnetic nanoparticles as efficient catalysts for esterification of free fatty acid
Water-tolerant heteropolyacid on magnetic nanoparticles as efficient catalysts for esterification of free fatty acid
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DOI：
10.1039/c3ra40219c
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发表时间：
2013-01-01
期刊：
影响因子：
3.9
通讯作者：
Li, Shiwu
中科院分区：
文献类型：
--
作者：
Duan, Xixin;Liu, Yue;Li, Shiwu
通过功能化磁性纳米粒子与杂多酸之间简单的酸碱相互作用，制备了磁性纳米粒子负载杂多酸。催化剂表面经有机基团改性，以保护催化位点不被水破坏。该杂化材料由磁性铁氧化物MNP核、SiO2壳层、氨基SiO2和表面有机基团组成，在温和的反应条件下催化棕榈酸与甲醇的酯化反应，2 h内FFA转化率达90.4%，飞行时间高达4.95 × 10（2）h（-1）。与其他固体酸催化剂相比，催化性能有利，证明了催化剂颗粒的小尺寸在减少传质限制和为基底提供更好地接近载体表面上的催化剂位点方面的优势。该催化剂在磁场作用下易于从反应混合物中分离出来，并显示出高稳定性和可回收性，在5个酯化循环后生产率没有显著损失。
Heteropolyacids (HPAs) supported on magnetic nanoparticles (MNPs) have been prepared by a simple acid-base interaction between functionalized magnetic nanoparticles and HPAs. The surface of the catalyst had been modified by organic groups to protect the catalytic sites from destruction by water. The hybrid SiO2-MNP-HPW consists of a core of magnetic iron oxide MNPs, silica shell, amino-silica and organic groups on the surface, which catalyzed the esterification of palmitic acid with methanol to give 90.4% FFA conversion within 2 h and a high TOF of 4.95 x 10(2) h(-1) under mild reaction conditions. The catalytic performance compared favourably to other solid acid catalysts, demonstrating the advantage of the small size of catalyst particles in reducing mass transfer limitations and providing the substrates with better access to the catalyst sites on the surface of carriers. The catalysts are easily separable from the reaction mixture under a magnetic field and showed high stability and recyclability, with no significant loss of productivity after five cycles of esterification.