Small gold clusters catalyzing oxidant-free dehydrogenation of glycerol initiated by methene hydrogen atom transfer

• Published in: Chinese chemical letters Vol. 30; no. 5; pp. 1000 - 1004
• Main Authors: Pembere, Anthony M.S., Cui, Chaonan, Wu, Haiming, Luo, Zhixun
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.05.2019; State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
• Subjects: Alcohols; Bond activation; Density functional theory; Energy barrier; Reaction path; Density functional theory; Bond activation; Reaction path; Energy barrier; Alcohols
• ISSN: 1001-8417; 1878-5964
• DOI: 10.1016/j.cclet.2018.12.019

We report a finding of feasible oxidant-free dehydrogenation of glycerol over small Au clusters, with a low-energy barrier of transition state initiated by hydrogen atom transfer from methene, which differs from the general reaction mechanism based on hydroxyl. [Display omitted] Developing oxygen-free methodology for the conversion of alcohols to carbonyls is essentially important because it suppresses the over-oxidation of alcohols to carboxylic acids and enables the production of energetic hydrogen. Here we report a finding of feasible oxidant-free dehydrogenation of glycerol over chemically-pure Au clusters synthesized by a green chemistry method named as laser ablation in liquid (LAL). As results, glycerol is dehydrogenated to form glyceraldehyde which undergoes subsequent dehydrogenation to hydroxymethyl glyoxal. For this, reaction dynamics calculations find interesting dehydrogenation reaction pathways with a low-energy barrier of transition state initiated by hydrogen atom transfer from methene, which differs from the general reaction mechanism based on hydroxyl. Furthermore, it is interesting that the presence of additional OH group molecules especially H2O can effectively lower the energy barrier in the activation of the OH and CH bonds in glycerol. This principle is also applicable to the oxidant-free dehydrogenation of methanol and ethanol, helping to fully understand the catalytic mechanism of alcohols conversion chemistry.