Production, separation and applications of phenolic-rich bio-oil--a review.

This paper provides an overview of current research trends in the production and separation of phenolic-rich bio-oils, as well as their applications. The first part of this paper highlights the strong dependency of the phenolic content of bio-oil on the kinds of biomass feedstock, reaction system, reaction conditions, and the type of catalysts used in their production. More recent separation technologies are also discussed in the second part of the paper. The final part of the paper deals with recent experimental results from applications of phenolic-rich bio-oils in the synthesis of phenolic resins. The paper suggests that the microwave-assisted pyrolysis of palm residues is a promising route for phenolic-rich bio-oil production, and that the use of supercritical CO2 and switchable hydrophilicity solvents during extraction, as well as molecular distillation techniques, can be applied to increase the recovery of phenolic compounds from bio-oils.