Solving the Water Hypersensitive Challenge of Sulfated Solid Superacid in Acid-Catalyzed Reactions

In the past decades, water tolerance has always been the long-pending key issue of sulfated solid superacids (SO ₄ ^2- /M _x O _y ) toward industrial applications. Herein, we report a strategy for the facile coating of a thick tunable hydrophobic layer over SO ₄ ^2- /M _x O _y , which can significantly improve water tolerance, with negligible inhibition on the catalytic performance of SO ₄ ^2- /M _x O _y . Even after being directly immersed in water, the hydrophobic SO ₄ ^2- /M _x O _y can still maintain above 90% of original catalytic activity, whereas pristine SO ₄ ^2- /M _x O _y and control samples are almost completely deactivated. This strategy opens a new route to enhance the water tolerance of sulfated solid superacids.