Research Progress and Prospects of Pyrolysis Oil from Corn Stover Lignin Extracted by Switchable Solvents

Amid global energy crises and environmental pollution, the valorization of renewable biomass resources like corn stover lignin is crucial. This review systematically examines the innovative application of switchable solvents (CO2-responsive, thermo-responsive, pH-responsive) for extracting lignin from corn stover and its subsequent pyrolysis into bio-oil. We critically analyze the extraction mechanisms, key process parameters (e.g., solvent type, temperature, solid-to-liquid ratio), and their intricate effects on lignin yield and purity. Furthermore, we delve into the pyrolysis kinetics, product distribution influenced by conditions (temperature, atmosphere, catalysts), and comprehensive characterization of the resulting bio-oil. This review highlights the broad application prospects of pyrolysis oil in energy, chemical feedstocks, and niche markets, while frankly addressing current challenges: high costs, product quality issues, and technological immaturity. Finally, we propose future directions focusing on green solvent design, process intensification, multi-technique characterization protocols, and the imperative for integrated lifecycle and techno-economic assessments to guide sustainable industrialization.