Lignocellulose pyrolysis by-products as an underestimated source of chemicals: separation and characterisation

Within the valorisation of lignocellulosic biomass, it is important not only to isolate the dominant compounds, but also to extract and purify the by-products. In this study, birch ( Betula pendula ) chips were used as feedstock in fast pyrolysis to obtain and purify levoglucosenone. Levoglucosenone was isolated by distillation, but the residual by-products were further fractionated by solid-phase extraction with a sequence of solvents: water, methanol, acetone and hexane. The focus was on the separation of the distillation residues and valorisation of levoglucosenone production by-products in order to promote a biorefinery approach to biomass pyrolysis. Combination of different analytical techniques—UHPLC-UV/MS, SEC-UV, FTIR, GC-MS and Py-GC-MS—has shown significant qualitative differences in the obtained fractions of the distillation residues, enabling a comprehensive characterisation and evaluation of the pyrolysis by-products.