Pyrolytic oil on the basis of wood and the antioxidant properties of its water-soluble and -insoluble fraction

Pyrolytic oils of different hardwood species were obtained in a two-stage ablative pyrolysis reactor. The GC/MS analysis of the pyrolytic oil has shown a different content of products of degradation of carbohydrates and lignin depending on the wood species. Pyrolytic oil were dispersed in water and separated to soluble and insoluble fractions. The fractions were characterised by the Py-GC/MS method. It is shown that the chemical composition of the water-soluble fractions differs from the composition of pyrolytic oils only insignificantly. In the composition of the water-insoluble fraction the amount of the products of degradation of carbohydrates decreases, while the content of monomeric phenolic compounds increases more then twice, and varies from 52.1 to 60.5% in the total sum of products for different wood species. The antioxidant properties, typical for lignin-containing preparations, were investigated by three independent methods. The results have shown that the water-insoluble fraction of pyrolytic oils, the so-called "pyrolytic lignin" can be regarded as a promising polymer antioxidant. (C) 2008 Elsevier B.V. All rights reserved.