Highly selective synthesis of primary amines from amide over Ru‐Nb₂O₅ catalysts

Abstract

Amines are an important class of compounds in natural products and medicines. The universal availability of amides provides a potential way for the synthesis of amines. Herein, Ru/Nb 2 O 5 catalyst is demonstrated to be highly efficient and stable for the selective hydrogenation of propionamide to propylamine (as a model reaction), with up to 91.4% yield of propylamine under relatively mild conditions. Results from XPS analyses, CO chemisorption, TEM images and DRIFTS spectra revealed that the unique properties of Nb 2 O 5 can effectively activate the C=O group of amides, and the smaller Ru particles on Nb 2 O 5 could further promote the activation, leading to superior catalytic performance of Ru/Nb 2 O 5 for amide hydrogenation. Meanwhile, reducing the surface acidity of Nb 2 O 5 can greatly inhibit the side reactions to by-products, and further enhance the selectivity to amine. Moreover, this catalytic system is also applicable for the hydrogenation of a variety of amides and provides high potential for the industrial production of primary amines from amides.

Hydrogenation of amides to amines by heterogeneous catalysis: a review

“…† Hereafter, Guo et al reported an efficient Ru/Nb 2 O 5 catalyst for the hydrogenation of propionamide to propylamine, achieving up to 91.4% yield. 85 Also, in this case, the addition of NH 3 was found to be essential for achieving high selectivity in the hydrogenation of aliphatic acyclic amides. This is attributed to the low steric hindrance of the desired amines that tend to dimerize, while the presence of NH 3 traps the intermediate, forming primary amines.…”

“…Firstly, the Ru/Nb 2 O 5 catalyst was demonstrated to be highly efficient and stable for the selective hydrogenation of propionamide to propylamine, which could be a promising approach for selective propylamine synthesis. 85 Characterization techniques revealed that Nb 2 O 5 can effectively activate the amide CvO group. Moreover, small-sized Ru particles are very efficient hydrogenation sites.…”