Valorization of glycerol into bio-fuel additives by condensation with acetone over tungstophosphoric acid immobilized in SBA-15

Abstract

The condensation of glycerol with acetone was carried out using dodecatungstophosphoric acid (PW) immobilized in SBA-15, at 70ºC. The main product of glycerol acetalisation was solketal. A series of catalysts, with different heteropolyacid loading (from 1.8 to 10.2 wt. %) were prepared. It was observed that the catalytic activity increases with the amount of PW immobilized in SBA-15, being the PW4-SBA-15 (with 10.8 wt. %) the most active sample. All catalyst exhibited good values of selectivity to solketal (about 99% near complete conversion). Catalytic stability of the PW4-SBA-15 was evaluated by performing consecutive batch runs with the same catalyst sample. It was observed that, after the third use, the catalytic activity stabilized. It was also observed a small leaching of heteropolyacid from SBA-15 to acetone.