Synthesis, characterization and solketal synthesis of SBA-15/SBA-16 supported metal exchanged heteropoly acid catalysts examination of its activity

The ketalization reaction of glycerol with acetone has recently gained importance in terms of evaluating glycerol, a by-product of biodiesel. In the first stage of this study, metal (Fe3+, Cu2+, Co2+, Ni2+) modified heteropoly acid (12-tungtophosphoric acid, 12-tungstosilistic acid, 12-molybdophosphoric acid) catalysts were synthesized. The synthesized catalysts were characterized by FT-IR, XRD, TGA, N2 adsorption/desorption and SEM-EDS analyzes using XRF, FT-IR, pyridine adsorption. The activities of M-HPA catalysts on glycerol conversions and solketal selectivity in solketal synthesis were investigated. It was observed that the most active catalyst in the ketalization reaction of glycerol was Fe-TPA catalyst with 100% glycerol conversion and 97% solketal selectivity. In the second stage of the study, Fe-TPA, which has the highest catalytic activity, was loaded on the SBA-15 and SBA-16 support material synthesized by wet impregnation methods at 20%, 30%, and 40% loading percentages. SBA-15 and SBA-16 were synthesized by the hydrothermal methods. The synthesized catalysts were characterized by the same characterization methods. The activities of the catalysts on glycerol conversion and solketal selectivity were investigated. The most active catalyst was found to be 40% Fe-TPA/SBA-15 catalyst with 100% glycerol conversion and 97% solketal selectivity. The reaction parameters were investigated with the most active catalyst and reusability experiments were carried out for 5 cycles, and it was found to be a sustainable catalyst with only 3.12% loss in glycerol conversion.