Hua Manli, Song Jinliang, Huang Xin, Fan Honglei, Wu Tianbin, Meng Qinglei, Zhang Zhanrong, Han Buxing
Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Colloid, Interface and Chemical Thermodynamics, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences Beijing 100190 China
School of Chemistry Engineering, University of Chinese Academy of Sciences Beijing 100049 China.
Chem Sci. 2022 Apr 11;13(18):5196-5204. doi: 10.1039/d2sc00579d. eCollection 2022 May 11.
Selective oxidative cleavage of the C(CO)-C bond in ketones to access esters is a highly attractive strategy for upgrading ketones. However, it remains a great challenge to realize this important transformation over heterogeneous metal-free catalysts. Herein, we designed a series of porous and ultrathin N-doped carbon nanosheets (denoted as CN-, where represents the pyrolysis temperature) as heterogeneous metal-free catalysts. It was observed that the fabricated CN-800 could efficiently catalyze the oxidative cleavage of the C(CO)-C bond in various ketones to generate the corresponding methyl esters at 130 °C without using any additional base. Detailed investigations revealed that the higher content and electron density of the graphitic-N species contributed to the excellent performance of CN-800. Besides, the high surface area, affording active sites that are more easily accessed, could also enhance the catalytic activity. Notably, the catalysts have great potential for practical applications because of some obvious advantages, such as low cost, neutral reaction conditions, heterogeneous nature, high efficiency, and broad ketone scope. To the best of our knowledge, this is the first work on efficient synthesis of methyl esters oxidative esterification of ketones over heterogeneous metal-free catalysts.
选择性氧化酮中的C(CO)-C键以制备酯是一种极具吸引力的酮升级策略。然而，在无金属多相催化剂上实现这一重要转化仍然是一个巨大的挑战。在此，我们设计了一系列多孔超薄的氮掺杂碳纳米片（表示为CN-，其中 代表热解温度）作为无金属多相催化剂。据观察，制备的CN-800能够在130°C下有效催化各种酮中C(CO)-C键的氧化裂解，生成相应的甲酯，且无需使用任何额外的碱。详细研究表明，石墨氮物种的较高含量和电子密度有助于CN-800的优异性能。此外，高比表面积提供了更容易接近的活性位点，也可以提高催化活性。值得注意的是，由于一些明显的优点，如低成本、中性反应条件、多相性质、高效率和广泛的酮适用范围，这些催化剂具有很大的实际应用潜力。据我们所知，这是第一项关于在无金属多相催化剂上通过酮的氧化酯化高效合成甲酯的工作。
