Selective synthesis of triacetyl glyceride biofuel additive via acetylation of glycerol over NiO-supported TiO2 catalyst enhanced by non-microwave instant heating

Abstract

NiO-supported TiO2 (nNiO/TiO2) as highly active and selective catalysts for triacetyl glyceride (TAG) biofuel additive production via acetylation of glycerol is reported. The catalysts are prepared by incorporating various amounts of Ni2+ (n = 10, 30 and 50 wt% Ni added during catalysts preparation) onto the TiO2 support using simple sol-gel approach followed by calcination. The spectroscopy and microscopy analyses reveal that the NiO nanoparticles (ca. 6 nm) are uniformly distributed on the surface of TiO2 support where octahedrally coordinated NiO as active species is formed upon calcination. Among the catalysts prepared, 30NiO/TiO2 with strongest acidity and highest accessible surface area is found to be the most active in the acetylation of glycerol with acetic acid, achieving 90.2% glycerol conversion with 65.9% selective to TAG under non-microwave instant heating conditions (170 °C, 30 min). In addition, 30NiO/TiO2 also shows better catalytic performance than previous reported catalysts. No significant deterioration in catalytic activity is shown by 30NiO/TiO2 after eight successive runs, thus offering a green pathway for synthesizing TAG vehicle fuel additives with high selectivity.