| Corn stalk powders (CSPs) were oxidized with NaOCl aqueous solution under mild conditions. The resulting solution and water-insoluble portion (WISP) were sequentially extracted. The WISP depolymerization was conducted in sub/supercritical methanol. The resulting reaction mixture was extracted with methanol. All the extracts were analyzed with a gas chromatography/mass spectrometer. A Fourier transform infrared spectrometer was used to analyze CSPs, WISP and methanol-inextractable portion (MIEP) from the above reaction mixture. Main components detected in the solution from CSPs oxidation are 1-4 ring aromatics, alkanes, alkenes, alkanoic acids and methyl alkanoates. Some value-added components were enriched by sequential extraction, e.g., after the solution was sequentially extracted with carbon disulfide, petroleum ether and diethyl ether, styrene, tricosane and 2,2-dichloroacetamide were enriched the corresponding extracts with more than 20% of relative contents. WISP was sequentially extracted with carbon disulfide, methanol and acetone. The content of methyl palmitate in the methanol-extractable portion (MEP) is as high as 57.9%. In total, 75 organic compounds, including 72 oxygen-containing organic compounds (OCOCs, i.e., methyl alkanoates, substituted phenols, substituted naphthalenes, ketones, heterocyclics, etc), were detected in MEP from sub/supercritical methanolysis of WISP. These OCOCs include 10 value-added compounds: furan-2-ylmethanol, tegafur, methyl lactate (Relative content 10.9%), 4-ethylphenol, methyl palmitate, dimethyl glutarate, 4-hydroxy-4-methyl-2-pentanone, 1,3,5-trimethoxybenzene, 2,6-dimethoxyphenol andγ-butyrolactone.The above results show that many value-added organic compounds can be enriched by the treatments (including mild oxidation, sub/supercritical methanolysis and sequential extraction techniques) of CSPs and the resulting reaction mixture, providing theoretical basis for efficient utilization of crop stalks.
|
PDF Full Text Request