OXIDATIVE DEPOLYMERIZATION AND STABILIZATION OF LIGNIN-DERIVED BIO-OILS

摘要

Lignocellulosic biomass is a promising fossil fuel alternative resource for chemicals and fuels. Fast pyrolysis of wood breaks down the complex polymeric components of cellulose, hemicellulose and lignin into low-molecular weight compounds in the absence of oxygen. More recently, pyrolysis of isolated lignin samples afforded bio-oils that have been upgraded using several techniques such as hydrodeoxygenation, zeolite cracking, steam reforming, and integrated catalytic processing. In addition, hydrotreatment of lignin pyrolysis vapors using inexpensive and sustainable iron-silica or iron-activated carbon (Fe/AC) catalysts affords aromatic compounds. Our group has been focused on obtaining value-added aromatic chemicals from lignin using selective oxidation catalysis. Herein, we compare (HQ)2V~v(O)(OiPr) catalyst with CuX/TEMPO (X = Cl, OTf) for aerobic oxidation of the lignin-derived bio-oils (HQ = 8-oxyquinoline, TEMPO = and Tf = triflate, SO2CF3). Catalysis converts oligomers/polymers present in the lignin-derived bio-oil into lower molecular weight compounds. We describe the analysis of the bio-oil with its oxidation products using GPC, 2D GC/MS, 1D and 2D NMR spectroscopy (HSQC).