2-Methylimidazole-Assisted Synthesis of Nanosized Cu3(BTC)2 for Controlling the Selectivity of the Catalytic Oxidation of Styrene
2-Methylimidazole-Assisted Synthesis of Nanosized Cu3(BTC)2 for Controlling the Selectivity of the Catalytic Oxidation of Styrene
复制标题
2·甲基咪唑辅助合成纳米Cu3(BTC)2用于控制苯乙烯催化氧化选择性
DOI：
10.1021/acsanm.8b01283
复制
发表时间：
2018-09-01
影响因子：
5.9
通讯作者：
Wang, Jide
中科院分区：
文献类型：
--
作者：
Guo, Changyan;Zhang, Yonghong;Wang, Jide
以2-甲基咪唑（2-MI）为有效竞争配体，以刘易斯碱为配体，合成了粒径为10-20 nm的纳米Cu-3（BTC）（2）（HKUST-1; BTC = 1，3，5-苯三甲酸酯）催化剂，并对其形貌和催化性能进行了优化。一方面，2-MI的加入可以加速桥连配体H3 BTC的去质子化，从而加速晶体的快速成核，导致溶液过饱和度迅速降低，抑制成核小晶体的进一步生长，最终得到纳米尺寸的HKUST-1晶体。另一方面，纳米HKUST-1中未配位的2-MI由于其碱性而可以提高晶体的催化性能。进一步的催化实验表明，纳米HKUST-1在无溶剂条件下对苯乙烯的可控氧化反应中表现出比本体HKUST-1更高的催化活性。更重要的是，苯甲醛和苯甲酸都成功地获得通过一个简单的变化的反应温度或时间。苯甲醛在50 ℃下9小时后可以以78%的气相色谱产率产生，或者在80 ℃下50分钟后可以以72%的气相色谱产率产生，而苯甲酸在80 ℃下6小时后可以以中等至良好的产率获得。值得注意的是，纳米HKUST-1可以方便地在四个循环中回收，而不会显著影响所需产物的产率。
A nanosized Cu-3(BTC)(2) (HKUST-1; BTC = 1,3,5-benzenetricarboxylate) catalyst with a size range of 10-20 nm was synthesized with 2-methylimidazole (2-MI) as an effective competitive ligand and Lewis base to tune its morphology and improve its catalytic performance simultaneously. On the one hand, the addition of 2-MI can accelerate deprotonation of the bridging ligand H3BTC, thereby accelerating the rapid nucleation of crystals, which leads to a rapid decrease of the solution supersaturation and inhibits further growth of the nucleated small crystal, resulting in nanosized HKUST-1 crystals. On the other hand, the uncoordinated 2-MI in nano-HKUST-1 can improve the catalytic performance of the crystal because of its basicity. Further catalytic experiments demonstrate that nano-HKUST-1 showed high catalytic activity compared with bulk HKUST-1 in the controllable oxidation of styrene under solvent-free conditions. More importantly, both benzaldehydes and benzoic acids were successfully obtained via a facile variation of the reaction temperature or time. The benzaldehydes can be produced in 78% gas chromatographic yield after 9 h at 50 degrees C or 72% after 50 min at 80 degrees C, while benzoic acids can be obtained in moderate-to good yield after 6 h at 80 degrees C. Notably, nano-HKUST-1 could be expediently recycled in four cycles without significantly affecting the yield of the desired product.