KCS

Direct benzoylation of the two hydroxyl groups on chitosan was achieved using phosphoryl mixed anhydride system, derived from trifluoroacetic anhydride (TFFA), benzoic acids (BAs), and phosphoric acid (PA). The reaction is operated as one pot process under mild conditions. And it does not requires neither inert atmosphere nor dry solvent. The structures of the synthesized compounds were confirmed by n.m.r and i.r spectroscopy. Solubility test on the compounds revealed that they were soluble in organic solvents such as N,N-dimethylformamide (DMF), dimethylsulfoxide (DMSO), acetone, and ethanol (EtOH). In the meantime, morphological study by a scanning electron microscorph (SEM) evidently indicated that the chitosan benzoates underwent significant structural change after the benzoylation.