Characterization of liquefied products from corn stalk in the presence of polyhydric alcohols with acid catalysis

Atmospheric liquefaction technology has been used widely and is an effective way of biomass component utilization. In this paper, the liquefied products obtained from corn stalk using polyhydric alcohols 1,2-propanediol (PG) mixed diethylene glycol (DEG) through acid catalysis under atmosphere pressure were characterized by various analytical technologies. The results indicated that 39 kinds of organic compounds were present in bio-oil, among which alcohols were the most, phenols were the second, and their relative contents were 70.7% and 25.6%, respectively. There were also some organic acids, ethers, esters, and ketones. More than 80% of these compounds had a carbon number less than 25. Carbon nuclear magnetic resonance spectra (13C-NMR) showed that different chemical shifts  (ppm) corresponded to various carbon types. The chemical composition of the residue from liquefaction was complex and contained a certain amount of large molecular substances that were difficult to degrade. It required more severe pyrolysis conditions than those of corn stalk. Results from X-Ray Diffraction (XRD) indicated the destruction of crystalline structure of carbohydrates and the cellulose molecules were cracked, indicating that the cellulose was degraded and the degree of liquefaction was high.