(533f) Enhancement Of Cellulose Sulfation Process Using Ionic Liquid Pre-Treatment Step | AIChE

(533f) Enhancement Of Cellulose Sulfation Process Using Ionic Liquid Pre-Treatment Step

Authors 

Wang, Z. - Presenter, Research Institute of Light Industry and Chemical Engineering, South China University of Technology, Guangzhou 510640, China
Li, L. - Presenter, South China University of Technology
Guo, S. - Presenter, Research Institute of Light Industry and Chemical Engineering, South China University of Technology, Guangzhou 510640, China


Abstract. Cellulose is the earth's most widespread renewable resource occurring at a volume of 700 billion tons. Value-promoting utilization of cellulose has aroused extensive attention throughout the world. Sulfation modification contributed to transferring cellulose into bio-active form cellulose sulphate(CS), which showed anticoagulant, antibacterial and antiviral activities. Increasing the degree of sulfation (DS) and improving the distribution of sulphate group along cellulose main chain are crucial for the activity. The highly ordered structure of cellulose has to be overcome in order to make the sulfation process viable for producing CS with expected bio-activity. In this study, an attempt was made to disrupt the cellulose structure using the ionic liquid, 1-butyl-3-methylimidazolium chloride ([C4mim]Cl), in a cellulose regeneration strategy which improved the subsequent sulfation reaction. Pretreatment process includes dissolving of cellulose with [C4mim]Cl and then following by regenerating with anti-solvents. De-ionized water, ethanol, actone and DMF were regarded as possible anti-solvents. The reaction parameters, including molar ratio of ClSO3H-DMF/anhydroglucose units(AGU) in cellulose, the effect of temperature and duration of the reaction were considered. The final products CS were characterized by UV,IR, 13C-NMR,GPC spectroscopy and elemental analysis. Results indicated that DMF appeared to be the most suitable anti-solvent according to the analysis of Sulfur content and intrinsic viscosity of CS. Pretreatment was found to increase the DS of CS from 0.86 to 2.13. A totally C2 and a partially C3 sulfate substitution were observed in CS derived from pretreated cellulose. It demonstrated that pre-treatment with [C4mim]Cl contributed to the uniform distribution of sulphate group along cellulose chain. The degradation of cellulose during sulfation process was delayed till 4h after reaction with pretreated cellulose as raw material, in contrast to only 1h after reaction with un-pretreated cellulose. The possible mechanism for enhancement of cellulose sulfation was due to the disruption of highly crystalline of cellulose ,based on the comparison of the structure of regenerated and unpretreated cellulose.