Highly Efficient and Superfast Cellulose Dissolution by Green Chloride Salts and Its Dissolution Mechanism

Cellulose dissolution is a worldwide issue in the production industry. Especially, the development of highly efficient and green cellulose solvents has been considered as a key factor to restrict the broad application of different cellulose industries. In this study, different chloride salts, such as LiCl, ZnCl2, CaCl2, and FeCl3, with different water amounts were used as green solvents to investigate the driving force of cellulose dissolution. The superfast and highly efficient cellulose dissolution in ZnCl2·3H2O and FeCl3·6H2O was successfully achieved within 5–20 min, which was confirmed by the results of polarized light microscopy. Moreover, the effect of pH and water amounts of the chloride salts on the cellulose structural change and dissolution ability was investigated for a better understanding of the role of chloride salts during the cellulose dissolution process. Especially, the dissolution mechanism of cellulose in ZnCl2·3H2O and FeCl3·6H2O has been provided compared to other non-derivatizing cellulose solvents.