Identification of the key oxidative intermediates and the function of chromium dopants in PKU-8: catalytic dehydrogenation of sec-alcohols with tert-butylhydroperoxide
Identification of the key oxidative intermediates and the function of chromium dopants in PKU-8: catalytic dehydrogenation of sec-alcohols with tert-butylhydroperoxide
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PKU-8 中关键氧化中间体的鉴定和铬掺杂剂的功能：用叔丁基过氧化氢催化仲醇脱氢
DOI：
10.1039/d0cy01822h
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发表时间：
2021
影响因子：
5
通讯作者：
Yang Tao
中科院分区：
文献类型：
--
作者：
Wang Weilu;He Yang;He Junkai;Dang Yanliu;Kankanmkapuge Tharindu;Gao Wenliang;Cong Rihong;Suib Steven L.;Yang Tao
使用绿色氧化剂的催化氧化反应在现代化学工程中发挥着重要作用，但原位生成的活性物种及其相关催化机理需要深入了解。为此目的，铬取代的铝硼酸盐Cr-PKU-8催化剂的合成和应用作为可回收的非均相催化剂的脂肪醇和芳香醇使用叔丁基过氧化氢（TBHP）的氧化。在水溶剂介质中，仲醇脱氢制丙酮的反应效率和选择性都很高（>99%）。从同位素示踪，分子探针和循环伏安法的分析策略，观察到的铬离子进行Cr 3 +-Cr2+-Cr 3+氧化还原循环。DFT计算表明，t-BuOO* 比t-BuO* 更有利于从仲醇中夺取氢，并且可能充当关键活性物种。根据实验结果，提出了解释催化过程的反应图式.
Catalytic oxidation reaction using green oxidants plays an important role in modern chemical engineering; however, the in situ generated active species and the related catalytic mechanism need to be understood in depth. For this purpose, Cr-substituted aluminoborate Cr-PKU-8 catalysts were synthesized and applied as recyclable heterogeneous catalysts for the oxidation of aliphatic and aromatic alcohols using tert-butylhydroperoxide (TBHP). Both high efficiency and selectivity (>99%) were achieved during the dehydrogenation of various sec-alcohols into acetone in H2O solvent medium. From the analyses using isotopic tracer, molecular probe and cyclic voltammetry strategies, the chromium ions were observed to undergo a Cr3+–Cr2+–Cr3+ redox cycle. DFT calculations suggest that t-BuOO* is more energetically favourable for hydrogen abstraction from sec-alcohol than t-BuO*, and probably acts as the key active species. Accordingly, the reaction scheme was proposed to interpret the catalytic process based on the observed results.