Continuous process of cellulose dissolution and transesterification reaction catalysed by ionic liquid in twin screw extruder

Abstract

More energy efficient and greener processes are needed today in chemical engineering. Reactive extrusion is an example of a new innovation targeting cleaner and more sustainable processes. In this work, we first examined the solubility of microcrystalline cellulose of two concentrations (10, 20 wt%) in a mixture of 1-ethyl-3-methylimidazolium acetate (EmimOAc)/DMSO using a twin screw extruder. Also, a new method of measuring residence time distribution inside the extruder was developed and discussed. EmimOAc/DMSO mixture was recovered and reused. Next, transesterification of cellulose using a long-chain acyl groups donor (vinyl laurate) was performed. The products of high degree of substitution (2.48–2.67) combined with great reaction efficiency (>80%) of the process as well as low E-factor (3.5) can be obtained in a continuous way using the co-rotating twin screw extruder. Finally, the effect of cellulose concentration on crystalline structure and mechanical properties of cellulose laurate films was evaluated.