Abstract
Propylation of cellulose from different sources with propionic anhydride usingN-iodosuccinimide (NIS) under solvent-free condition was tested. It was done in the presence of NIS as a new catalyst for propylation using three different amounts of catalyst under mild reaction conditions. The degree of substitution by propionate was experimentally calculated and confirmed by FTIR and(1)H NMR analyses. The propylation yields varied from 71.54 to 88.37% with the degree of substitution (DS) ranged from 1.32 to 2.80 for commercial cotton cellulose, 1.76-3.00 for rice husk cellulose, and 1.60-3.0 for wheat straw cellulose. The DS were easily controlled by changing the reaction duration (2-6 h) and the amount of the NIS catalyst (50, 75, and 100 mg for each 1.0 g of cellulose) in 25 mL of propionic anhydride. Prolonging the reaction's duration has no favorable effect on the propylation process and led to decrease in the cellulose propionate (CP). Also, increasing the amount of NIS catalyst results in decrease the DS and CP yield. NIS was recognized as a novel and more successful catalyst for propylation of the hydroxyl groups of cellulose from different sources in high degree of substitution.