Characterization of the Soluble Products Formed during the Hydrothermal Conversion of Biomass-Derived Furanic Compounds by Using LC–MS/MS

[Image: see text] To reveal the hydrothermal conversion routes of the biomass-derived furanic compounds, the soluble products formed during the hydrothermal conversion of 5-hydroxymethylfurfural (HMF), furfural, and furfuryl alcohol were analyzed by liquid chromatography–mass spectrometry (LC–MS) and LC–MS/MS. Multiple carbocyclic compounds containing hydroxy group and carbonyl group were detected, with a molecular mass in the range of 154–272 Da and carbon chain of the length 8–15. The formation of these soluble carbocyclic compounds was proposed to involve hydrolytic ring-opening of the furanic ring, intermolecular aldol condensation, intramolecular aldol condensation, and C–C cleavage reaction. The C–C cleavage reaction was proposed to occur on the dicarbonyl structure of the formed primary polymers.