Hydrolysis of mechanically pre-treated cellulose catalyzed by solid acid SO_4~(2-)-TiO_2 in water–ethanol solvent

An efficient catalyst SO_4~(2-)-TiO_2(ST) from industrial metatitanic acid has been successfully prepared to catalyze hydrolysis of ball-milling cellulose. The results show that the highest catalytic efficiency is obtained for ST calcined at 450 °C(ST-450) with the yield of 21.8% glucose, 13.0% 5-HMF and 4.2% furfural at 200 °C for30 min. The ball milling of cellulose and solid acid catalyst significantly enhances the cellulose hydrolysis. The high Lewis to Br?nsted acid sites ratio for ST-450 induced by bidentate ligands between SO_4~(2-)and TiO_2 benefits high organics yield, and high total acid sites contribute to the high cellulose conversion. The large pore volume of0.29 cm~3·g~(-1) and appropriate pore size of 7.35 nm of ST-450 also contribute to the high performance. High reaction temperature over 200 °C exhibits negative effect on glucose and 5-HMF yield due to undesired side reactions, while furfural product is stable in the reaction system. The bidentate ligands between SO_4~(2-)and TiO_2 are considered as active acid sites for cellulose hydrolysis in water–ethanol solvents.

Hydrolysis of mechanically pre-treated cellulose catalyzed by solid acid SO42--TiO2 in water-ethanol solvent

An efficient catalyst SO₄^2--TiO₂ (ST) from industrial metatitanic acid has been successfully prepared to catalyze hydrolysis of ball-milling cellulose. The results show that the highest catalytic efficiency is obtained for ST calcined at 450℃ (ST-450) with the yield of 21.8% glucose, 13.0% 5-HMF and 4.2% furfural at 200℃ for 30 min. The ball milling of cellulose and solid acid catalyst significantly enhances the cellulose hydrolysis. The high Lewis to Brönsted acid sites ratio for ST-450 induced by bidentate ligands between SO₄^2-and TiO₂ benefits high organics yield, and high total acid sites contribute to the high cellulose conversion. The large pore volume of 0.29 cm₃·g^-1 and appropriate pore size of 7.35 nm of ST-450 also contribute to the high performance. High reaction temperature over 200℃ exhibits negative effect on glucose and 5-HMF yield due to undesired side reactions, while furfural product is stable in the reaction system. The bidentate ligands between SO₄^2-and TiO₂ are considered as active acid sites for cellulose hydrolysis in water-ethanol solvents.