Tosylation Optimization, Characterization and Pyrolysis Kinetics of Cellulose Tosylate

Cellulose tosylates with different degree of substitution (DS) were prepared by reacting cellulose in DMAc/LiCl with p‐tosyl chloride at 8 °C in the presence of triethylamine. The effects of number of mole of tosyl chloride (A), number of mole of base (triethylamine) (B) and reaction time (C) on DS were studied by Response Surface Methodology (RSM) known as Box‐Behnken Design (BBD). It was found that A is the main factor influencing DS and the interaction between B and C is negligible. An optimal DS value of 2.79 was obtained with A=6.96 and B=2.99 mol eq. at a reaction time C=24 h. The synthetic polymers were characterized by elemental analyses, FT‐IR, NMR and SEM spectroscopy. The results indicated that the cellulose was successfully tosylated with various DS. Cellulose tosylate with DS=0.5 and DS=2 were subjected to thermo‐gravimetric analysis under inert atmosphere. The kinetic parameters were determined by Coats‐Redfern method. Thermal analyses and kinetics indicates that the lower DS of tosyl group the higher thermal stability is. Thus, cellulose lose its stability after esterification with p‐tosyl chloride. Cellulose tosylates with various degrees of substitution (DS) were prepared in DMAc/LiCl. The response surface methodology (RSM) model was used to study the influences of different parameters. Microcrystalline cellulose and cellulose tosylates with DS values of 0.5 and 2 were subjected to thermo‐gravimetric analysis in order to approach the mechanisms and kinetics of their thermal degradation. The kinetic parameters were determined by the Coats‐Redfern method.