Catalytic pyrolysis of mannose as a model compound of hemicellulose over zeolites

• Catalytic pyrolysis has a significant impact on the quality of bio-oil.
• Catalytic effect on mannose pyrolysis was investigated.
• The dehydration, cracking and deoxygenation were enhanced under catalysis.
• A route for mannose pyrolysis was proposed to illustrate products distribution.

Mannose was selected as a model compound of hemicellulose and its thermal behavior over zeolites has been investigated using a TG-FTIR analyzer. There was an initial study of the chemical structure of mannose and a characterization of the catalysts. All three catalysts, HZSM-5, H-β and USY, had a significant influence on the dehydration, cracking and deoxygenation reactions during the pyrolysis of mannose. The dehydration reaction in the initial stage was enhanced, resulting in two separate water release processes, while the char formation was suppressed. USY had the best effect on dehydration, and HZSM-5 obtained the highest deoxygenation efficiency. The presence of HZSM-5 and H-β catalyzed the formation of water and CO2, while suppressing the formation of oxygenated compounds and char residues.