Preparation of furfural by catalytic pyrolysis of cellulose based on nano Na/Fe-solid acid

Abstract

In this study, a new-type of Na/Fe solid acid catalyst was synthesized to achieve efficient conversion of cellulose into furfural. The influence of Na/Fe mass ratios (0.05–2%), pyrolysis temperature (350–750 °C), and catalyst to cellulose ratio (0.2:1–20:1) was investigated through pyrolysis–gas chromatography/mass spectrometry (Py-GC/MS), and the structure of Na/Fe catalyst was characterized with various approaches. Through scanning electron microscopy (SEM), the morphologies of the catalysts were found to exhibit rod-like, prismatic, spherical, and amorphous shapes with increasing Na/Fe. The results indicated that the selectivity of furfural increased with increasing Na/Fe ratio, and reached the highest value (61.4%) at a Na/Fe ratio of 1.42, after which it decreased with further increases in the Na/Fe ratio. Higher temperature and higher catalyst to biomass ratio are favorable for furfural formation, but exceedingly high temperature and catalyst to biomass ratio inhibit its formation. The maximum furfural yield could be achieved at 550 °C and catalyst to cellulose ratio of 10. The proposed catalytic pathway of cellulose pyrolysis for furfural is the promotion of the conversion of glucose monomers into dehydrated sugars such as LGO and DGP, which undergo secondary cracking to form furfural.