Low-temperature hydrothermal liquefaction of pomelo peel for production of 5-hydroxymethylfurfural-rich bio-oil using ionic liquid loaded ZSM-5.

Ionic liquid loaded ZSM-5 with high stability and catalytic performance was used for hydrothermal liquefaction (HTL) of pomelo peel for the first time. Bio-oil obtained at 200 °C had the highest yield (29.21 wt%) and high heating value (21.41 MJ/kg), with main constituents of 5-hydroxymethylfurfural (5-HMF, 50.10%), 3-Pyridinol (19.8%) and pentanoic acid (5.35%). The higher 5-hydroxymethylfurfural yield obtained using ionic liquid loaded ZSM-5 was further compared to other studies (0-50%). In comparison to high-temperature HTL, catalytic HTL with ionic liquid loaded ZSM-5 led to lower activation energy requirements (31.93 kJ·mol) for the conversion of glucose into 5-HMF. Additionally, the catalysts showed excellent recyclability, with 19.68 wt% of bio-oil containing 59.6% of light oil obtained after 5 cycles. Hence, this study presents a novel approach for the catalytic conversion of lignocellulosic biomass into 5-HMF-rich bio-oil for energy and green chemistry applications.