One-step catalytic amination of naphthalene to naphthylamine with exceptional yield

Abstract

One-step amination of aromatic compounds to arylamines is a promising strategy with high atom economy and less environmental pollution. We propose for the first time a direct catalytic amination of naphthalene to naphthylamine and hydroxylamine using vanadium catalysts under mild conditions. Naphthylamine was obtained in 70% yield over the V₂O₅/HZSM-5 cayalyst in a one-step amination of naphthalene, which is higher than the yield obtained by state-of-the-art processes. The Brønsted acid sites, and the V–O–V and VO bonds of monovanadate in the V₂O₅/HZSM-5 catalyst are the active sites for the amination reaction and are responsible for the naphthalene activation and formation of NH₃⁺ that acts as the active amination reagent. A possible reaction mechanism was also proposed by investigating real-time IR and in situ DRIFTS. This proposed one-step amination of naphthalene is superior to traditional nonselective nitration and hydrogenation processes, and some findings offer new insights to produce arylamines from aromatic compounds.