Porous Nanostructured Catalysts Based on Silicates and their Surface Functionality: on the Effects of Silica Source and Metal added in Glycerol Valorization

A series of nanospherical shaped silicates containing heteroatoms (Al, Zr or Ti) were successfully synthesized using TEOS or silica colloids as silicon source. These metallosilicate nanospheres were used as silicon nutrients to obtain silicalite zeolites having micro-mesoporosity with improved textural properties. The results demonstrated that TEOS acted as a suitable silicon source to produce amorphous silicates and a spherical-type hierarchical zeolite architecture with Zr and Ti heteroatoms included in their framework, with preferable particle size and crystallinity. The surface functionality of the mesostructured nanospheres and zeolite silicates provide active centers for the esterification of glycerol with acetic acid (EG) reaction. Besides, the dispersion of Cu or Fe entities on the surface of the nanospherical silicates and zeolites provided good catalytic performances in the esterification of glycerol to valuable acetins.