Theoretical study on the mechanisms of cellulose dissolution and precipitation in the phosphoric acid-acetone process

► Featuring cellulose dissolution and precipitation mechanism in H3PO4 and acetone. ► Hydrogen bond with EB of −1.61 eV favoring the dissolution of cellulose in H3PO4. ► Cellulose delocalizing in H3PO4 with Egap of 4.46 eV. ► Chemical stability of cellulose in different solvents during pretreatment.