Issue 2, 2025

Lattice oxygen insertion mechanism in CeO2-catalyzed reactions in water: nitrile hydration reaction

Abstract

Cerium oxide (CeO2) exhibits prominent catalytic activity in various organic reactions owing to its unique acid–base and redox properties. One of the most interesting applications of pure CeO2-catalyzed organic reactions is the hydration of nitriles in water. The experimental results showed that the hydration of 2-cyanopyridine to picolinamide in water using CeO2 catalysts proceeds readily at low temperatures (30–100 °C) in high yields and that this reaction occurs exclusively on CeO2 among various metal-oxide catalysts. To elucidate the unique catalytic activity of CeO2, the reaction mechanism is dissected using the density functional theory-based molecular dynamics (DFT-MD) simulations. Based on the free energy analysis, it is demonstrated that the reaction proceeds with the involvement of the surface lattice oxygen, where the lattice oxygen atom is inserted into picolinamide. The involvement of the surface lattice oxygen is notably uncommon given the low temperatures of the reaction, and this computational prediction is verified by the two experiments using H218O solvent and 18O-exchanged CeO2 catalyst, where the introduction of surface lattice oxygen into picolinamide is confirmed. The inherent flexibility of the surface lattice oxygen and the unique acid–base properties of CeO2, which can favorably bind and activate both nitrile and water molecules, are key factors in the high reactivity for various organic reactions, which characterizes the outstanding catalytic activity of CeO2.

Graphical abstract: Lattice oxygen insertion mechanism in CeO2-catalyzed reactions in water: nitrile hydration reaction

Supplementary files

Article information

Article type
Edge Article
Submitted
17 Sep 2024
Accepted
30 Nov 2024
First published
02 Dec 2024
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY license

Chem. Sci., 2025,16, 939-951

Lattice oxygen insertion mechanism in CeO2-catalyzed reactions in water: nitrile hydration reaction

T. Endo, T. Ikeda, K. Muraoka, Y. Kita, M. Tamura and A. Nakayama, Chem. Sci., 2025, 16, 939 DOI: 10.1039/D4SC06294A

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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