Homogeneous acetylation and regioselectivity of cellulose in a new ionic liquid

Homogeneous acetylation of cellulose in 1-allyl-3-methyl-imidazolium chloride (AMIMCl) was carried out. Acetic anhydride and acetyl chloride were used as acetylating agents in the absence and presence of pyridine. The degree of substitution (DS) of the products and the distribution of substituents were determined by titration and C-13 NMR techniques respectively. It was observed that acetyl chloride reacted faster than anhydride. Further, pyridine accelerated the reactions when anhydride was used as the acetylating agent, while it slowed down the reactions when acetyl chloride was used. An interesting distribution of DSC-2 >> DSC-3 for substitutes was observed in the product with acetic anhydride/pyridine system.