Degradation of lignin by means of catalytic depolymerization for the preparation of monophenolic compounds, and then obtaining high value-added platform chemicals as well as liquid fuels, is of great significance for alleviating energy problems and environmental pollution. In this paper, we carried out a study on the structure of corn stover lignin and pyrolysis of oleophenolic products, selected a variety of CO₂-switching solvents, and explored the mechanism of the influence of solvent type and extraction parameters on the selectivity of oleophenolic products. The results showed that the lipophilicity of the switching solvent, the extraction time, the particle size of lignin, the material-liquid ratio and the ultrasonic time all had important effects on the extraction of the oleophenolic products at room temperature and normal pressure, and the optimal extraction conditions were as follows: DMCHA as the solvent, the material-liquid ratio of 1:4, the particle size of the lignin was less than 0.30 mm, the extraction time was 80 min, and the ultrasonic time was 25 min. Meanwhile, in the case of β- O-4 bond content is low in corn stover lignin (CSL), the extraction capacity of the solvent is favorable to obtain and stabilize the monophenolic compounds. Whereas, when the content of β-O-4 bonds was high, other characteristics of the solvent would affect the depolymerization of lignin and the selectivity of the products. In addition, there is a solvent effect between the phenolic compounds in the lignin pyrolysis products and the switching solvent.
