Catalyst-free N-dealkylation of aniline derivatives in water induced by high frequency ultrasound†

Here we report that cavitation bubbles, formed by the ultrasonic irradiation of a liquid at a high frequency, induce the catalyst-free N-dealkylation of aniline derivatives in water, thus opening an alternative pathway to current technologies which require transition metals and hazardous solvents or oxidants. Mechanism investigations revealed that the N-dealkylation of aniline derivatives takes place at the cavitation bubble–water interface, a region where N–C bond thermal cracking reactions occur. Advantageously, the N-dealkylation of aniline derivatives can also specifically occur in the presence of other components, thanks to their strong interaction at the cavitation bubble–water interface. This specific transfer of the acoustic energy to aniline derivatives represents a notable advantage over current cracking technologies, which lead to non-chemical specific cracking due to the heating of the whole reactor.