Abstract: The catalytic pyrolysis of cellulose was investigated using H-ZSM-5 with different Si/Al ratios and Zn/ZSM-5 catalysts with different Zn content. The nature of these catalysts was characterized by ammonia temperature programmed desorption (NH₃-TPD), IR spectra of pyridine adsorption, and X-ray diffraction (XRD) techniques. The no-catalytic and catalyic pyrolytic behaviors of cellulose were studied by thermo-gravimetric (TG) technique, and pyrolytic liquid product, i.e. bio-oil, was analyzed by gas chromatography-mass spectrometry (GC-MS). The major components of bio-oil are described as follows: anhydrosugars including levoglucosan (LGA, 1,6-anhydro-β-glucopyranose), levoglucosenone (LGO, 1,6-anhydro-3,4-dideoxy-β-D-pyranosen-2-one), 1,4:3,6-dianhydro-α-D-glucopyranose (DGP), furan compounds such as furfural and 2,5-dimethyl furan, aldehydes, etc. H-ZSM-5 and Zn/ZSM-5 samples with Brönsted acid and Lewis acid sites exhibited a remarkable effect on the pyrolytic behaviors of cellulose, where H-ZSM-5 could increase the yield of bio-gas but decrease the yield of bio-char and bio-oil. Moreover, it was found that Brönsted acid and Lewis acid sites could enhance the formation of a specific compound of bio-oils, e.g. Zn ions could produce some esters.

Key words: levoglucosenone, levoglucosan, 6-dianhydro-α-D-glucopyranose, Zn/ZSM-5, pyrolysis