Renewable chemical feedstocks from peanut shell liquefaction: Preparation and characterization of liquefied products and residue

The objective of this investigation is to liquefy peanut shell for the preparation of aromatic polyol-rich products. The influences of reaction parameters are discussed. It is found that, compared to single-solvent, the mixture of polyethylene glycol and glycerol as solvents shows higher liquefaction efficiency. And the maximum liquefaction yield of 98.7 wt % can be achieved when the sulfuric acid content, mass ratio between polyethylene glycerol, glycerol, and peanut shell powder, liquefaction temperature, and time are 17 wt % (relative to peanut shell), 8/2/1, 150 degrees C, and 2 h, respectively. Furthermore, the solubility test result indicates that the liquefied products are fully soluble in the water and polyol. Meanwhile, the properties of the peanut shell and liquefaction residue were analyzed by means of attenuated total reflectance-Fourier transform infrared spectroscope, thermal gravity analysis, and scanning electron microscope. The polysaccharide is degraded by the cleaving of C-O bond, and the lignin is decomposed by leaving the dominant linkages including beta-O-4, 4-O-5, and dibenzodioxocin units. The fibers in the peanut shell are broken, and the nondegraded components in the residue lost their network structure. (C) 2016 Wiley Periodicals, Inc.