Hierarchically porous BEA stannosilicates as unique catalysts for bulky ketone conversion and continuous operation

Abstract

Pore size limitations typically limit the applicability of Lewis acidic zeolites, such as titano- and stanno-silicates, to catalytic processes based on small-to-mid sized substrates, and increase their rates of deactivation, prohibiting further exploitation. Herein, we demonstrate that tin-containing zeolites possessing modified hierarchical BEA matrices can be prepared. These hierarchical stannosilicates are able to mediate the catalytic conversion of bulky ketone substrates, a pertaining challenge in the field that purely microporous analogues are unable to mediate. Deactivation studies in the continuous regime also demonstrate the exceptional stability of hierarchical Sn-Beta compared to purely microporous Sn-Beta, with <20% loss of activity observed over 700 h on stream. In contrast, the purely microporous analogue lost ±70% activity in only 200 h. To the best of our knowledge, this is the first time a stannosilicate with a beneficial hierarchical BEA framework has been prepared, and the first evidence of cyclododecanone valorisation with stannosilicate catalysts.