Selective Oxidation of Benzyl Alcohol Catalyzed by Palladium Nanoparticles Supported on Carbon-Coated Iron Nanocrystals

A magnetic separable Pd nanoparticles catalyst supported on carbon-coated iron nanocrystals (Pd/Fe@C) was prepared by an impregnation method and characterized by X-ray fluorescence spectroscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The size of the Pd nanoparticles ranged from 4–10 nm and the average size was about 7 nm. The principal component of the Pd nanoparticles was determined to be Pd0 with a Pd 3d5/2 binding energy at 335.6 eV. The as-made catalyst was applied to the selective oxidation of benzyl alcohol. Its effects on the oxidation of benzyl alcohol were investigated in detail including the amount of catalyst, the solvent, the temperature, and the catalytic activities of recycling. The results indicated that benzaldehyde could be selectively synthesized from benzyl alcohol upon catalysis by Pd/Fe@C. The conversion of benzyl alcohol was 96% and the selectivity for benzaldehyde was 95% when using 0.5 mol% Pd/Fe@C catalyst with acetonitrile as a solvent under an oxygen atmosphere at 80 °C. The catalyst can be easily separated magnetically and high catalytic activity was retained after recycling the catalyst four times.

摘要以碳包铁纳米晶 (Fe@C) 为载体, 采用浸渍法制备了一种磁可分离的 Pd/Fe@C 催化剂, 并运用 X 射线荧光光谱、透射电镜、X 射线衍射和 X 射线光电子能谱对催化剂进行了表征. 结果表明, 纳米 Pd 颗粒的粒径分布在 4∼10 nm, 平均粒径约为 7 nm, Pd 物种以 Pd0 为主, 其 Pd 3d5/2 结合能为 335.6 eV. 将该催化剂应用于苯甲醇选择性氧化反应, 考察了催化剂用量、溶剂、温度对反应的影响以及催化剂的循环使用性能. 结果表明, 催化剂可使苯甲醇高选择性生成苯甲醛, 在催化剂用量 (摩尔分数) 为 0.5%、乙腈为溶剂、80 oC 常压 O2 条件下, 苯甲醇的氧化反应效果最佳 (苯甲醇转化率为 96%, 苯甲醛选择性为 95%). 催化剂易于磁分离和回收, 循环使用 4 次仍保持较佳的催化性能.

An effective green route is evaluated for the transformation of benzyl alcohol to benzaldehyde using a magnetically separable palladium nanoparticles supported on carbon-coated iron nanocrystals catalyst.Figure optionsDownload as PowerPoint slide