Tianjin Key Laboratory of Chemical Process Safety and Equipment Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300350, P.R. China.
Heibei Key Laboratory of Hazardous Chemicals Safety and Control Technology, School of Chemical and Environmental Engineering, North China Institute of Science and Technology, Langfang, Hebei 065201, China.
Inorg Chem. 2023 Mar 27;62(12):4872-4882. doi: 10.1021/acs.inorgchem.2c04196. Epub 2023 Mar 14.
Selective oxidation of cyclohexane to cyclohexanol/cyclohexanone (KA-oil) is an important chemical process, which is still constrained by low conversion and selectivity and high energy consumption. In this study, Cu-doped mesoporous TiO (Cu-MT) has been successfully synthesized via calcinating MIL-125(Ti) doped with copper acetylacetonate, which shows high reactivity in selective oxidation of cyclohexane to KA-oil by persulfate (PS) with the desirable cyclohexane conversion of 16.8% and a selectivity of 98.0% under mild conditions and the low ratio of PS/cyclohexane of 1:1. A series of characterizations and density functional theory calculations reveal that the doped Cu(I,II) on Cu-MT is the reactive site for non-radical activation of PS with the moderate elongation of the O-O bond in PS, which then abstracts 1H (1H + 1) from cyclohexane to form Cy and eventually KA-oil. This study gives new insight on the importance of moderately activated PS in selective oxidation of C-H.
环己烷选择氧化为环己醇/环己酮（KA 油）是一个重要的化学过程，但该过程仍受到转化率和选择性低以及能耗高的限制。在这项研究中，通过煅烧掺杂铜乙酰丙酮盐的 MIL-125(Ti)，成功合成了铜掺杂介孔 TiO2（Cu-MT），其在过硫酸盐（PS）存在下用于环己烷选择氧化制 KA 油时表现出很高的反应活性，在温和条件下环己烷的转化率为 16.8%，选择性为 98.0%，PS/环己烷的比例低至 1:1。一系列的表征和密度泛函理论计算表明，Cu-MT 上掺杂的 Cu(I,II)是 PS 非自由基活化的反应活性位，其可适度拉长 PS 中的 O-O 键，然后从环己烷中抽取出 1H（1H + 1），生成 Cy 并最终生成 KA 油。该研究为适度活化的 PS 在 C-H 选择氧化中的重要性提供了新的认识。
