The acetylation of the corn cob under mild conditions, in the presence of NBS, using acetic anhydride was carried out using the method of Sun et al. [12] for acetylation in a solvent free system. The amount of substrate and reactant were combined in a ratio of 1:20 (g dried corn cob/mL acetic anhydride). The reaction temperature, time and amount of catalyst were varied respectively from 30 8C to 130 8C, 1 to 3 h and 0 to 4%. The mixture of raw corn cob, acetic anhydride and catalyst was placed in a round bottom flask fitted to a condenser. The flask was placed in an oil bath on top of a thermostatic heating device, thereafter, the flask was removed from the bath and the hot reagent was decanted off. The corn cob was thoroughly washed with ethanol and acetone to remove unreacted acetic anhydride and acetic acid as by-products. The new products were dried in an oven at 60 8C for 16 h prior to analysis. The extent of acetylation (EA) was estimated from the infrared spectra by calculating the ratio of the absorption intensities (I) for the vibration signals of C55O (around 1740– 1745 cm1) and C–O (1020–1040 cm1), as shown below