Catalytic conversion of concentrated miscanthus in water for ethylene glycol production

Miscanthus, a promising energy crop, was used for ethylene glycol (EG) production through one-pot catalytic conversion. With a binary catalyst composed of commercial tungstic acid and Raney Ni, the miscanthus with 1 % concentration was transformed into EG with a yield of 35.5%. However, the yield dropped to 13.6% as the miscanthus concentration was increased to 10 %. The underlying reason for the yield decrease was disclosed through analysis of the liquid products, investigation of pretreatments, and characterization of the catalysts. It was found that the protectors on the surface of miscanthus and the lignin component underwent decomposition under reaction conditions, resulting in the formation of some organic acids and unsaturated compounds that preferentially poisoned the Raney Ni catalyst and consequently decreased the EG yield. When the inhibitors were effectively removed by base solvent pretreatment, the EG yield was successfully improved to 39.0% even under 10% concentration of feedstock.