Catalytic fast pyrolysis of furfural over H-ZSM-5 and Zn/H-ZSM-5 catalysts

Furfural, a cellulose model compound, was converted into gasoline-range fuels through catalytic fast pyrolysis. H-ZSM-5-based catalysts were employed in a continuous fixed bed system. The reaction temperature, reactant contact time, and catalytic promoter are keys to manipulate the product distribution. The first step in furfural conversion is the decarbonylation of furfural to form furan, followed by furan conversion to intermediates (e.g., cyclohexene and 3,4-dimethylbenzaldehyde) in the ZSM-5 pores. These intermediates can then be transformed into aromatics, coke, light olefins, and carbon oxides. A reaction temperature of 500°C generated the highest yield of aromatics and the lowest amount of coke. A long contact time (∼1.5 s) also provided the highest aromatic selectivity. The promoter, zinc oxide, plays an important role in hydrogen atom transfer. This is attributed to the change of acid site concentration and Lewis acid sites created by anchored Zn ions.