Lewis and Brønsted Acid Synergistic Catalysis for Efficient Synthesis of Hydroxylamine over Heteroatom Zeolites
Nan Fang, Kai Huo, Yucheng Jin, Dongxu Liu, Huanhao Lin, Huiying Wu, Xuguang Liu, Yueming Liu, Mingyuan He
Abstract
Environmental and efficient synthesis of NH 2 OH is challenging. Herein, we have provided a route for efficient NH 2 OH formation by NH 3 oxidation via the synergistic catalysis of Lewis acid sites of the framework Ti (Ti LAS) and Brønsted acid sites of the framework Al (Al BAS) in Ti–Al-MOR zeolites. Ti LAS was the active center for formation of transition-state NH 2 OH, while Al BAS could provide the proton H to convert transition-state NH 2 OH absorbed on Ti LAS to a [NH 3 OH] + species. Protonation effect would not only promote the catalytic cycle process resulting from accelerating the desorption of transition-state NH 2 OH, but also improve the stability of NH 2 OH, being less prone to oxidative decomposition. In this work, we presented the synergistic catalysis between LAS and BAS over Ti-containing heteroatom zeolites to accelerate the catalytic cycle, which provided an environmental and efficient method for NH 2 OH formation.