Dehydration of Amides to Nitriles over Heterogeneous Silica‐Supported Molybdenum Oxide Catalyst

Abstract Silica‐supported molybdenum oxide (MoO x /SiO 2 ) with 4.8 wt% Mo (0.5 mmol g −1 ) was an effective and reusable heterogeneous catalyst for dehydration of 2‐furamide to 2‐furonitrile (96 % yield). The catalyst was applicable to the dehydration of various amides including heteroaromatic, aromatic and alkyl amides, providing the corresponding nitriles in high yields (87‐97 %). Based on the results of catalyst characterizations (XRD, TEM, UV‐vis, Raman) and activity tests, MoO x species are highly dispersed over SiO 2 , and heptamolybdate anion ([Mo 7 O 24 ] 6− ) and isolated dioxo ((O=) 2 MoO 2 ) were mainly formed on the SiO 2 support of the optimal MoO x /SiO 2 catalyst. The strong Brønsted acid sites (Mo‐OH−Si site) can be formed from the MoO x species and the adjacent silanol group, and the acid‐base pair site (Mo(=O)−OH−Si site) of the strong Brønsted acid site (Mo−OH−Si site) and base site (Mo=O) over MoO x /SiO 2 catalyst could be the main active site for the dehydration of amides.