Targeted conversion of furfural from waste wood via catalyzed pyrolysis of acid-leaching residue

Furfural is an essential platform compound for organic chemicals. However, the low selectivity of furfural via fast pyrolysis of biomass hinders the widespread application. Herein, a novel method for preparing furfural-rich bio-oil from waste wood catalyzed by acid-leaching residue (ALR) is reported for the first time. The bio-oil yield reaches 74.87 wt%, and the highest reported furfural yield is 95.41 area% when pyrolyzed with a 1:4 mass ratio of waste wood to ALR at 500 °C. Chlorination of the ALR catalyst surface provides abundant Brønsted acid sites and drastically facilitates the directional selectivity of furfural. The furfural formation mechanism is investigated using monosaccharides as model compounds. The C5 sugars can be converted directly to furfural via dehydration, whereas the C6 sugars require a multistep conversion, producing by-products. This method realizes the reuse of waste wood and ALR, providing a new approach for preparing low-cost furfural.