Method for preparing nano lignin by using oxygen catalytic ethanol and application of method

The invention belongs to the technical field of resource regeneration and utilization and particularly relates to a method for preparing nano lignin by using oxygen catalytic ethanol and application of the method. Under a low-temperature low-pressure condition, lignin is extracted by using oxygen catalytic ethanol, and compared with a conventional catalytic ethanol pulping technique, the method issafe in pulping process and high in lignin yield. The method is technically characterized by comprising the following steps: putting crushed straw into a reaction kettle, and adding an ethanol solution; introducing oxygen into the reaction kettle, after air above a material is completely substituted by the oxygen, sealing the reaction kettle; heating, and keeping the temperature to implement reactions; after the reactions end, opening the valve of the reaction kettle, and releasing the pressure; after pressure release is completed, filtering immediately, and separating the straw from a liquid; distilling the liquid,