<br>环氧化物气相多相氢化中仲氢诱导的极化,The Journal of Physical Chemistry C

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环氧化物气相多相氢化中仲氢诱导的极化
The Journal of Physical Chemistry C ( IF 3.3 ) Pub Date : 2023-12-06 , DOI: 10.1021/acs.jpcc.3c05059
Oleg G. Salnikov ₁ , Ekaterina V. Pokochueva ₁ , Dudari B. Burueva ₁ , Larisa M. Kovtunova _{1,

2} , Kirill V. Kovtunov ₁ , Igor V. Koptyug ₁

Affiliation

环氧化物的氢化是一个具有基础和实际重要性的反应。在此，使用仲氢诱导极化（PHIP）技术研究了二氧化钛负载的 Pt、Pd 和 Rh 催化剂上饱和和不饱和环氧化物的气相非均相氢化。饱和环氧化物（环氧乙烷和环氧丙烷）的氢化产生醇、羰基化合物、烯烃和烷烃。虽然所研究的所有三种催化剂在 H ₂ 存在下均将环氧化物异构化为羰基化合物，但只有 Pd/TiO ₂ 在惰性气氛下表现出催化活性，这意味着在 Pt 和 Rh 催化剂上，环氧化物C-O键只能在H原子加成的同时断裂形成烷氧基。检测到丙烷和丙烯的 PHIP 效应，但未检测到醇的 PHIP 效应。双官能环氧化物 3,4-环氧-1-丁烯的氢化产生 11 种反应产物。反应物通过其 C=C 键吸附，然后加氢，形成 1,2-环氧丁烷，该丁烷不会进一步反应。或者，反应物可以通过其C=C键和氧原子被吸附，导致形成巴豆醛、丁醛、巴豆醇、1-丁醇、甲基1-丙烯基醚、甲基丙基醚、1,3-丁二烯、1-丁烯、2-丁烯和丁烷。基于PHIP效应观察，提出了相应过程的机理。

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Parahydrogen-Induced Polarization in Gas-Phase Heterogeneous Hydrogenation of Epoxides

Hydrogenation of epoxides is a reaction of both fundamental and practical importance. Herein, gas-phase heterogeneous hydrogenation of saturated and unsaturated epoxides over titania-supported Pt, Pd, and Rh catalysts was investigated using the parahydrogen-induced polarization (PHIP) technique. Hydrogenation of saturated epoxides (ethylene oxide and propylene oxide) yielded alcohols, carbonyl compounds, alkenes, and alkanes. While all three catalysts under study isomerized epoxides to carbonyl compounds in the presence of H₂, only Pd/TiO₂ showed catalytic activity under inert atmosphere, implying that on Pt and Rh catalysts, the epoxide C–O bond can be cleaved only simultaneously with H atom addition to form alkoxy species. PHIP effects were detected for propane and propylene but not for alcohols. Hydrogenation of bifunctional epoxide 3,4-epoxy-1-butene yielded 11 reaction products. Adsorption of the reactant via its C═C bond is followed by hydrogen addition, resulting in the formation of 1,2-epoxybutane, which does not react further. Alternatively, the reactant can be adsorbed via both its C═C bond and the oxygen atom, leading to the formation of crotonaldehyde, butanal, crotyl alcohol, 1-butanol, methyl 1-propenyl ether, methyl propyl ether, 1,3-butadiene, 1-butene, 2-butene, and butane. Based on the PHIP effects observation, the mechanisms of the corresponding processes were proposed.

更新日期：2023-12-06

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