Conversion of Ammonia to Hydrazine Induced by High‐Frequency Ultrasound
Anaelle Humblot, Laurie Grimaud, Audrey Allavena, Prince Nana Amaniampong, Karine De Oliveira Vigier, Tony Chave, Stéphane Streiff, François Jérôme
Abstract
Abstract Hydrazine is a chemical of utmost importance in our society, either for organic synthesis or energy use. The direct conversion of NH 3 to hydrazine is highly appealing, but it remains a very difficult task because the degradation of hydrazine is thermodynamically more feasible than the cleavage of the N−H bond of NH 3 . As a result, any catalyst capable of activating NH 3 will thus unavoidably decompose N 2 H 4 . Here we show that cavitation bubbles, created by ultrasonic irradiation of aqueous NH 3 at a high frequency, act as microreactors to activate and convert NH 3 to NH species, without assistance of any catalyst, yielding hydrazine at the bubble–liquid interface. The compartmentation of in‐situ‐produced hydrazine in the bulk solution, which is maintained close to 30 °C, advantageously prevents its thermal degradation, a recurrent problem faced by previous technologies. This work also points towards a path to scavenge . OH radicals by adjusting the NH 3 concentration.