Solubility test was evaluated by dissolution method. After 100 g BMIMCl solvent was heated to 100◦C, an appropriate amount of cellulose samples was added into it with vigorous stirring for 10 min at 100 ◦ C to obtain a transparent cellulose solution. The remaining undissolved fractions were washed using water and ace- tone, respectively, and then dried at 60 ◦ C for 24 h in a vacuum oven.