Microwave-assisted catalytic conversion of cellulose into 5-hydroxymethylfurfural in ionic liquids

Microwave-assisted direct conversion of cellulose into HMF in ionic liquids catalyzed by ZrCl4 has been investigated in search of an efficient and environment-friendly process. Firstly, some representative metal chlorides were used to catalyze the conversion of glucose into HMF, and it was demonstrated that ZrCl4 was superior to other catalysts. Then direct conversion of cellulose into HMF was catalyzed by ZrCl4 under microwave irradiation (MI). Under optimal conditions, a high HMF yield up to 51.4% was obtained from cellulose in 3.5 min under MI at 400 W. Controllable experiments indicated that both ionic liquids, MI and ZrCl4 showed synergetic effects on the efficient conversion of cellulose into HMF. This work provides a meaningful method for the conversion of carbohydrates into fine chemicals.

• We show an efficient way for the conversion of cellulose into HMF in ionic liquid.
• HMF was obtained in a high yield of 51.4% from cellulose with ZrCl4 under MI.
• [Bmim]Cl, ZrCl4, and MI show synergetic effects on the high yield of HMF.
• This catalytic system could be reused for several times without losing activity.