Ma Qianli, Cheng Jianian, Wu Xiaojing, Xie Jin, Zhang Ruihui, Mao Zhihe, Yang Hongfang, Fan Wenjun, Zeng Jianrong, Bitter Johannes Hendrik, Li Guanna, Li Zelong, Li Can
Key Laboratory of advanced catalysis, College of Chemistry and Chemical Engineering, Lanzhou University, 730000, Lanzhou, China.
State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, 730000, Lanzhou, China.
Nat Commun. 2025 Jan 2;16(1):140. doi: 10.1038/s41467-024-55640-w.
Compared to the sluggish kinetics observed in methanol-mediated side-chain alkylation of methyl groups with sp C-H bonds, CO hydrogenation emerges as a sustainable alternative strategy, yet it remains a challenge. Here, as far as we know, it is first reported that using CO hydrogenation replacing methanol can conduct the side-chain alkylation of 4-methylpyridine (MEPY) over a binary metal oxide-zeolite ZnZrO/CsX tandem catalyst (ZZO/CsX). This ZZO/CsX catalyst can achieve 19.6% MEPY single-pass conversion and 82% 4-ethylpyridine (ETPY) selectivity by using CO hydrogenation, which is 6.5 times more active than methanol as an alkylation agent. The excellent catalytic performance is realized on the basis of the dual functions of the tandem catalyst: hydrogenation of CO on the ZZO and activation of sp C-H bond and C-C bond coupling on the CsX zeolite. The thermodynamic and kinetic coupling between the tandem reactions enables the highly efficient CO hydrogenation and C-C bond coupling. In-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and density functional theory (DFT) calculations suggest that the CHO* (CHO*) species, rather than methanol produced from CO hydrogenation, is the key intermediate to achieve the C-C bond coupling.
与甲醇介导的甲基与sp C-H键的侧链烷基化反应中观察到的缓慢动力学相比，CO加氢成为一种可持续的替代策略，但仍然是一个挑战。据我们所知，本文首次报道使用CO加氢替代甲醇，可在二元金属氧化物-沸石ZnZrO/CsX串联催化剂（ZZO/CsX）上实现4-甲基吡啶（MEPY）的侧链烷基化反应。该ZZO/CsX催化剂通过CO加氢可实现19.6%的MEPY单程转化率和82%的4-乙基吡啶（ETPY）选择性，作为烷基化剂其活性是甲醇的6.5倍。这种优异的催化性能是基于串联催化剂的双重功能实现的：在ZZO上CO的加氢以及在CsX沸石上sp C-H键的活化和C-C键偶联。串联反应之间的热力学和动力学偶联实现了高效的CO加氢和C-C键偶联。原位漫反射红外傅里叶变换光谱（DRIFTS）和密度泛函理论（DFT）计算表明，CHO*（CHO*）物种而非CO加氢产生的甲醇是实现C-C键偶联的关键中间体。
