College of Materials & Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310036, China.
Key Lab of Applied Chemistry of Zhejiang Province, Department of Chemistry, Zhejiang University, Hangzhou 310027, China.
Molecules. 2022 Oct 17;27(20):6965. doi: 10.3390/molecules27206965.
The direct hydroxylation of benzene is a green and economical-efficient alternative to the existing cumene process for phenol production. However, the undesired phenol selectivity at high benzene conversion hinders its wide application. Here, we develop a one-pot synthesis of protonated g-CN supporting vanadia catalysts (V-pg-CN) for the efficient and selective hydroxylation of benzene. Characterizations suggest that protonating g-CN in diluted HCl can boost the generation of amino groups (NH/NH) without changing the bulk structure. The content of surface amino groups, which determines the dispersion of vanadia, can be easily regulated by the amount of HCl added in the preparation. Increasing the content of surface amino groups benefits the dispersion of vanadia, which eventually leads to improved HO activation and benzene hydroxylation. The optimal catalyst, V-pg-CN-0.46, achieves 60% benzene conversion and 99.7% phenol selectivity at 60 C with HO as the oxidant.
苯的直接羟化是一种绿色、经济高效的替代方法，可替代现有的异丙苯工艺生产苯酚。然而，在高苯转化率下，不希望的苯酚选择性阻碍了其广泛应用。在这里，我们开发了一种在盐酸中质子化 g-CN 负载氧化钒催化剂（V-pg-CN）的一锅法合成方法，用于高效和选择性地苯羟化。表征表明，在稀盐酸中质子化 g-CN 可以在不改变体相结构的情况下促进氨基（NH/NH）的生成。表面氨基的含量决定了氧化钒的分散性，通过在制备中添加的 HCl 的量可以很容易地调节。增加表面氨基的含量有利于氧化钒的分散，从而最终提高 HO 的活化和苯的羟化。最佳催化剂 V-pg-CN-0.46 在 60°C 下以 HO 为氧化剂，苯转化率为 60%，苯酚选择性为 99.7%。
