Characterization of liquefied products from corn stalk and its biomass components by polyhydric alcohols with phosphoric acid

[Display omitted] •The cellulose, hemicellulose and lignin were directly separated from corn stalk.•The main components and structure of bio-oil were detected by GC–MS, NMR and FTIR.•The carbon number of each component in bio-oil was analyzed by TGA.•Corn stalk degradation process was studied by liquefaction of its components. The hemicellulose, cellulose and lignin were directly separated from corn stalk, and their liquefaction processes were investigated via acid-catalyzed solvolysis treatment with 1,2-propylene glycol (PG) and diethylene glycol (DEG) to produce bio-oil and residues. The main components, functional groups and organics structure of bio-oil were analyzed by the FTIR, 1H-NMR, 13C-NMR, GCMS, and TGA. It was found that there had a similar tendency in the liquefaction processes of cellulose, hemicellulose and lignin. Corn stalk and its biomass components were degraded and formed plentiful low-molecular polymers by acid catalysis, prior to polymers were converted into corresponding PG/DEG-derivatives. Finally, low-molecular weight soluble substances and insoluble residues were generated by decomposition and polymerization. Additionally, more than 80% compounds’ carbon number in four bio-oils was below 25. The residues were mostly stemmed from macromolecules produced by degradation products and PG/DEG or re-polymerization between degraded small molecules.