FTIR and Mass Spectral Analyses of an Upgraded Bio-oil.

Bio-oil prepared from flash pyrolysis of rice stalk around 500°C was upgraded by filtration and catalytic esterification. Both raw and upgraded bio-oils were observed with an optical microscope. The upgraded bio-oil was extracted with benzene, carbon disulfide, hexane, and carbon tetrachloride, respectively, and the soluble fractions were analyzed with FTIR and GC/MS. In addition, ion trap mass spectrometer was used for analysis of the benzene-soluble fraction. The results show that the upgrading substantially improved the dispersity of organic droplets in the bio-oil and completely removed char particles from the bio-oil, but heavy species are still the main components in the upgraded bio-oil; the soluble fractions contain aliphatic, benzene-ring-containing, ester, and bonded hydroxyl moieties, and methoxy-containing species are the most abundant GC/MS-detectable compounds. [ABSTRACT FROM AUTHOR]