Sustainable transformation of biodiesel byproduct: Acetalization of glycerol with benzaldehyde through UiO-66(Zr)

This work reports the first systematic application of a metal–organic framework catalyst, UiO-66(Zr), in the heterogeneous acetalization of glycerol with benzaldehyde. The catalyst was synthesized solvothermally and exhibited high crystallinity and structural robustness, with a BET surface area of 1017 m2/g.

A 32 full factorial design was employed to optimize the reaction system, identifying temperature and catalyst loading as the most influential parameters. Under the optimized conditions (130 °C, 20 wt.% catalyst, 24 h), a maximum benzaldehyde conversion of 84 % was achieved, showing a robust correlation between experimental results and model predictions. Notably, the overall product distribution was shifted toward the 5-RING derivatives (ca. 70 %), in contrast to the predominance of 6-RING products commonly reported for conventional acid catalysts.