Isolation and Characterization of the Phenolic Fractions of Wood Pyrolytic Oil

A fraction of pyrolytic oils (PyO) – obtained by fast pyrolysis of alder (Alnus incana), ash-tree (Fraxinus excelsior) and aspen (Populus tremula) in a laboratory scale reactor – was precipitated in water. This hydrophobic moiety of PyO is called pyrolytic lignin (PyL). The composition of the volatile monomeric compounds of PyO and the PyL fraction was determined by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). It has been found that PyL has a high content of phenolic products (between 75% and 83%), which varies depending on the wood species. The antioxidant properties of the PyL fraction were studied and it was demonstrated that the antioxidant activity determined in different tests exceeded the corresponding activity of alkali lignin. The antioxidant properties of PyL are on the same level as those of the widely used antioxidants, such as rutin, trolox, curcumine, and tert-butylhydroquinone (TBHQ). A new method was developed for the extraction of a monomeric phenol fraction (Py-monPh) from PyO by means of the organic solvent methyl tert-butyl ether (MTBE). The Py-monPh can be considered as a promising source of antioxidant

Py-GC/MS for Characterization of Non-Hydrolyzed Residues from Bioetanol Production from Softwood

Analytical pyrolysis combined with gas chromatography/mass spectrometry (Py-GC/MS) was used to analyze chemical composition of non-hydrolyzed residues (LHRs) obtained by three methods of bioethanol production: softwood acid hydrolysis (AH), separate enzymatic hydrolysis and fermentation (SHF), and simultaneous saccharification and fermentation (SSF). Complementary techniques, such as EPR- and FTIR-spectroscopy, and routine chemical analysis procedures were used for this study as well. The Py-GC/MS analysis of the LHRs has shown a higher efficiency of carbohydrates hydrolysis upon SSF process in comparison with SHF and AH processes. Comparison of chemical analysis results and data obtained by Py-GC/MS of LHRs brought the direct evidence of incorporation of carbohydrates-derived fragments into the lignin matrix and formation of so-called pseudo-lignin upon different stages of softwood processing. Modifications of lignin component of LHRs on various stages of the process of bioethanol production, such as oxidation and condensation reactions, cleavage of ether bonds and destruction of side propane chain, were revealed using Py-GC/MS