Discovering the role of substrate in aldehyde hydrogenation

In this manuscript, we investigated in detail one of the critical parameters that govern the reactivity of the carbonylic group toward hydrogenation and hydrodeoxygenation: the effect of the side chains of aldehydes. We observed that the presence of a pi-electron conjugation on the side chains strongly affects the conversion of aldehydes to alcohols and hydrocarbons under the reaction conditions studied. In particular, the presence of a strong pi-electron conjugation, such as the aromatic ring, enables the hydrogenation and further hydrodeoxygenation of the carbonylic group, while, on the other hand, molecules with no or weak pi-electron conjugation (such as alkyl chains or single conjugated C = C double bonds) remained inactive. These results were supported by adsorption analyses as well as theoretical models, which showed that differences in adsorption mode and strength between two model substrates (benzaldehyde and octanal) were not the decisive factors in the conversion of the carbonyl group. (C) 2021 Elsevier Inc. All rights reserved.

Automated summary

This study investigates the impact of side chains on the reactivity of aldehydes towards hydrogenation and hydrodeoxygenation, finding that pi-electron conjugation strongly influences the conversion of aldehydes to alcohols and hydrocarbons. Strong pi-electron conjugation, such as an aromatic ring, enables hydrogenation and hydrodeoxygenation of the carbonylic group, while molecules with no or weak pi-electron conjugation remain inactive. The results are supported by adsorption analyses and theoretical models, indicating that differences in adsorption mode and strength are not the decisive factors in carbonyl group conversion.