A green catalyst for hydrolysis of cellulose: Amino acid protic ionic liquid

Natural amino acids were chosen as excellent precursors for the synthesis amino acid protic ionic liquids (AAPILs) and they can be easily converted to cations and properties of functionalities incorporate into ionic liquid. Herein, we reported the study to catalyze hydrolysis of cellulose in 1-butyl-3-methylimidazolium chloride solvent by using different structure of AAPILs, which were synthesized via a one-step acid-base neutralization reaction. In addition, amino, hydroxyl and carboxyl functional groups on the AAPILs serving as catalytic domain and binding domain can promote cellulose hydrolysis. Moreover, a remarkable total reducing sugar yield of 67.1% was achieved by lysine derived ionic liquid within 1.5 h at 130 °C while the cellulose conversion was nearly 100%, which was attributed to its more catalytic sites. On the whole, AAPILs are promising catalysts for the differential conversion of inedible cellulose owing to its low cost, sustainable renewable and potential biodegradable.