Tosylation Optimization, Characterization and Pyrolysis Kinetics of Cellulose Tosylate
Lahcen El Hamdaoui, Amine Es‐Said, Maryam El Marouani, Mehdi El Bοuchti, Rahma Bchitou, Fatima Kifani‐Sahban, Mohammed El Moussaouiti
Abstract
Abstract 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.