Seperation of syringol from birch wood-derived vacuum pyrolysis oil

A birch wood sample (Betula papyrifera) composed of 54% sapwood and 46% bark was pyrolyzed in a pilot plant reactor, The products were 53.9% condensates (pyrolysis oil including 8% reaction water), 24.0% gas and 22.1% wood charcoal (anhydrous initial feed basis). The pyrolysis oil was steam distilled and the recovery of phenols at various steam pyrolysis oil ratios was studied. A 14.9% by wt. of volatile pyrolysis oil fraction (based on the total feed oil) was recovered at a steam:oil ratio of 27. The distillate was analyzed by GC/MS after acetylation and showed 21.3% by wt. of phenolic compounds on the pyrolysis oil basis. The distillate was further distilled under a total pressure of 0.7 kPa. About 16 sub-fractions were recovered. The steam-distilled fractions were found to be chemically and thermally stable when subjected to further purification processes. The 2.6-dimethoxyphenol (syringol)-rich fraction was separated and purified. Syringol with a purity of 92.3% was obtained. (C) 2001 Elsevier Science B.V. All rights reserved.