Aromatics from biomass pyrolysis vapour using a bifunctional mesoporous catalyst

Abstract

Zeolites with uniform intracrystal mesopores, designated MSU-MFI, were prepared using silane-modified polymers as mesopore-generating agents. X-ray diffraction analysis of this catalyst showed Braggs peaks representative of MFI structure. Catalyst characterization by nitrogen physisorption revealed a mesoporous structure with high surface area, pore size and volume. The MSU-MFI catalysts developed in this study were selective toward aromatic chemical production from poplar pyrolysis vapour. Yields of generalized products and aromatics were comparable to those obtained from conventional microporous ZSM-5 analogs as demonstrated by pyroprobe-gas chromatography/mass spectrometry and thermogravimetric analysis. While ZSM-5 was more selective to smaller C6 aromatics and naphthalenes, MSU-MFI catalysts were more selective to C8 and C9 monoaromatics. The incorporation of gallium(III) ions in MSU-MFI using the incipient wetness method increased aromatic yields by up to 15% over Ga-free catalysts and decreased the coke production by up to 6% (p < 0.05). Due to high yields and low coke formation, Ga-MSU-MFI offers an improved option for making non-oxygenated aromatic chemicals from photosynthetic biomass.