Selective extraction of monophenols from pyrolysis bio-oil based on a novel three-dimensional visualization model

Monophenols in pyrolysis bio-oil can be used to produce renewable fuels and various other materials; their clean separation, however, remains a great challenge. This study provides an economical and feasible strategy for efficiently extracting monophenols from bio-oil. In order to determine the interaction between bio-oil components and different solvents, Hansen solubility parameter theory was used to predict the dissolution trend of several model compounds (e.g., 6 monophenols and 2 dimeric phenols) with a relatively high concentration and/or typical dissolution characteristics in the bio-oil feedstock. A new three-dimensional graphical model was then established by observing the distribution of the extractant coordinate points (Hansen solubility parameters) to predict the selectivity of the extraction of monophenols in a specific extraction process. Under the guidance of this dissolution model, a multistep extraction process with a mono phenol yield of 88.2 wt% was established, and the mass percentage of mono phenols in the separation product was about 86.3%. We performed catalytic hydrodeoxygenation on the separation product, and results showed that the yield and aromatic selectivity of the product were significantly higher than those of water-washed bio-oil. Since the separation strategy proposed in this study does not involve acids or alkalis and the solvent is easily recyclable, the method is expected to find practical application in the efficient separation of bio-oil and its downstream value-added refinement.