Ultrasound-Assisted\nSequential Extraction for Lignocellulose\nPyrolysis Bio-Oil Fractionation. Part I: Method Development

The work herein presents a novel ultrasound-assisted\nsequential\nextraction (UASE) method for fractionating bio-oils derived from lignocellulosic\nbiomass pyrolysis. The fractionation method uses hexane, toluene,\nand dichloromethane, to produce fractions with distinctive composition\nwith minimal sample loss as no stationary phases are used. Characterization\nof the fractions and the original bio-oil by gel permeation chromatography\n(GPC), proton nuclear magnetic resonance (<sup>1</sup>H NMR), gas\nchromatography–mass spectrometry (GCMS), and pyrolysis-GCMS,\nrevealed marked compositional differences between the fractions. Lighter\nfractions contained a high concentration of light aromatic compounds,\nideal for hydrogenation into fuel, whereas heavier fractions showed\nsimilarity to lignin standards with an increased presence of sugar-like\ncompounds. This study introduces a novel fractionation technique for\nbio-oil analysis and establishes a framework to standardize bio-oil\nquality assessment, with plans to apply these methods to various bio-oils\nin future research.