Hydrophobic functionalization of HY zeolites for efficient conversion of glycerol to solketal

Production of solketal by glycerol acetalization is a promising pathway to add values to glycerol. Our evidence indicated that, initially, the reaction was limited by poor interfacial mass transfer. Acetone slowly diffused and solubilized in the glycerol phase, where it reached the catalyst's active sites to form solketal. We describe a strategy that overcomes this interfacial mass transfer limitation by grafting an organosilane surfactant (n-octadecyltrichlorosilane (OTS)) onto the surface of an HY catalyst. The OTS-grafted HY catalyst became hydrophobic and assisted in emulsion formation between the two immiscible reactants, minimizing the interfacial mass transfer limitation. As a result, the OTS-HY catalyst produced high catalytic activity (89% conversion) compared with that of HY (28% conversion) at 30 °C after 60 min. The high catalytic activity of organosilane-modified HY catalyst at low temperature makes it a promising candidate for other acid-catalysed two-phase reactions.