Formic acid as a catalyst in furfural production by simultaneous extraction processes via steam stripping and biphasic systems

Formic acid, a promising organic acid used as a solvent for lignocellulosic biomass depolymerization, is also an efficient catalyst for converting xylose to furfural. Investigating reaction temperature (100–200 °C), residence time (0–60 min), and initial xylose concentration (2–30 g/L) in synthetic solutions, optimal conditions emerged: 170 °C, 40 min, and 10 g/L xylose, yielding 58 % furfural. Both the steam stripping and the water/cyclopentyl methyl ether biphasic system demonstrated significant advantages in furfural production. They achieved 80 % and 70 % furfural yields, respectively, with a separation efficiency exceeding 90 % using 30 g/L of xylose. This surpassed the 54 % yield achieved in batch processing. Under identical conditions, the fir wood hydrolysate resulted in 50 %, 72 %, and 76 % furfural yields in batch, semi-batch, and biphasic systems. Similarly, the hydrolysate from oil palm empty fruit bunch yielded 70 %, 79 %, and 83 % furfural in the corresponding systems. The suggested processing method can be effectively included in current lignocellulosic biorefinery systems.