Rapid transesterification of cellulose in a novel DBU-derived ionic liquid: Efficient synthesis of highly substituted cellulose acetate

Cellulose acetate (CA) is one of the most important cellulose plastics that has demonstrated extensive applications in many areas. In search of a more sustainable and efficient way to prepare CA, we synthesized a novel ionic liquid, [DBUC8]Cl, based on the commonly used catalyst DBU (1,8-diazabicyclo[5.4.0]undecyquin-7-ene) in a simple manner. [DBUC8]Cl can dissolve cellulose more efficiently than the same type of imidazolyl ionic liquid, owing to the stronger alkalinity of DBU. It is noteworthy that highly substituted CA (DS = 2.82) was successfully synthesized via transesterification with alkenyl ester under mild conditions (80 degrees C, 40 min) without the addition of a catalyst in this solvent, which is superior to most of the reported work. Furthermore, we confirmed that the synthesized CA had good thermoplasticity, and a transparent cellulose acetate film (CAF) was obtained by hot pressing with a small amount of glycerol. Therefore, we propose a new DBU-derived ionic liquid, which may serve as a versatile platform system for producing cellulose-derived bioplastics more sustainably and efficiently.

Automated summary

A novel ionic liquid, [DBUC8]Cl, was synthesized and found to have stronger alkalinity than other imidazolyl ionic liquids, enabling more efficient dissolution of cellulose. Highly substituted cellulose acetate (CA) was successfully synthesized under mild conditions without the use of a catalyst, and a transparent cellulose acetate film (CAF) was obtained. The new DBU-derived ionic liquid offers a versatile platform for sustainable and efficient production of cellulose-derived bioplastics.