Molecular design and experimental study of the conversion of cellulose to 5-HMF catalyzed by different ratios of Brønsted /Lewis acidic deep eutectic solvents

• Design of 15 acidic DESs - catalyzed cellulose conversion to 5-HMF. • Mild reaction conditions and 43.23% yield. • DES still has high catalytic activity after several cycles. • The mechanism of this tandem reaction was predicted.