Compositions of compounds extracted from thermo-treated wood using solvents of different polarities

How well modified wood products perform may be influenced by their chemical compositions. Wood extractives are nonstructural constituents, many with specific biological properties, which affect the color, fragrance, hygroscopicity, durability, and acoustic properties and the drying and adhesion processes of wood. However, incomplete information is available on the extraction techniques and potential use of extractives as value-added chemical products. The main goal of this research was to explore the effects of thermo-vacuum treatment of Deodar cedar (Cedrus deodara Roxb.) and Italian alder (Alnus cordata Desf.) woods on the content and composition of extractives. Solvents with different polarities were used, including water, hexane, dichloromethane, methanol, and a benzene/ethanol mixture. Component groups in extracts were determined by gas chromatography in combination with mass spectrometry. Regardless of the treatment and solvent, the most representative extracts to be obtained from alder were acids/esters, whereas hydrocarbons were most frequently obtained from cedar. Our results revealed an interesting differential species-specific effect of solvents on the composition of extracts. Aside from benzene/ethanol, greater amounts of extracts were obtained from treated than from untreated alder, whereas the opposite was true for cedar, aside from methanol.