Catalytic Reductive Depolymerization of Corncob Lignin to Produce Bio-oil via Formic Acid/Ethanol System
Keywords:Corncob, Lignin, Depolymerization, Formic acid, Bio-oil
Formic acid (FA) was used for reductive depolymerization of industrial corncob lignin via ethanol and Pt/C system. The highest yield of bio-oil obtained was 71.4% when the reaction was conducted at 260 °C with an FA/lignin ratio of 8 for 0.5 h. The bio-oil was composed of oligomers (Mw within 600 Da) and lignin depolymerized fragments (Mw beyond 600 Da). Reaction temperature was the most important factor affecting the properties of bio-oil. Although excessive temperature could increase the C/H ratio and higher heating value (HHV) of bio-oil, it would lead to repolymerization of lignin degraded fragments, thus resulting in a higher molecular weight of bio-oil. Additionally, alkylphenols were major products in bio-oil, and the amount of alkyl phenols could be increased by increasing the temperature and extending the retention time appropriately. This study reveals the effects of various reaction conditions on the yield and properties of bio-oil, providing a theoretical basis for subsequent upgrading of bio-oil to biofuels and aromatic chemicals.