Transesterification of β-ketoesters catalyzed by hybrid materials based on silica sol–gel

This work shows an alternative process for β-ketoester transesterification using new silica-based hybrid materials as heterogeneous catalysts. The catalysts were synthesized using silica and 3-aminopropyltriethoxysilane or 1,1,1,3,3,3-hexamethyldisilazane as functionalizating agents. β-Ketoesters and alcohols were transesterified in refluxing toluene with reaction times between 4 h and 14 h. Different ketoesters with good performance were obtained. The influence of the catalysts and starting materials on the reaction rate was studied. In all cases, coproduct formation was not observed; the catalysts were recovered and reused without loss of catalytic activity.