SBA-15 functionalized sulfonic acid containing a confined hydrophobic and acidic ionic liquid: a highly efficient catalyst for solvent-free thioacetalization of carbonyl compounds at room temperature

A novel application of SBA-15 functionalized sulfonic acid containing a confined ionic liquid has been introduced to convert various carbonyl compounds to their corresponding dithioacetals and dithioketals at room temperature and under solvent-free conditions. It was found that coating SBA-15-Pr-SO3H with the hydrophobic and acidic ionic liquid [OMIm] HSO4 at a loading of 0.8 mL g(-1) of silica, afforded paths for faster mass transfer of the starting materials into the active sites. At the same time it might also increase the Bronsted acid strength as a result of an acid site cooperativity mechanism. The catalyst can be easily recovered and reused for at least eight reaction cycles with only a slight loss in its catalytic activity.