|MadSci Network: Chemistry|
Assuming that your acetic anhydride was of good quality (it is moisture sensitive) and that you allowed sufficient time for the reaction, I see no reason why it would not work. Raising the temperature may help speed up the reaction, and there are various degrees of acetylation, the lower levels of acetyl group incorportion may not change the properties of cotton enough to be noticeable. Catalyst may help too, I would suggest a bit of toluenesulfonic acid, or dimethylformamide or even 4-dimethylaminopyridine. Acetic acid as a solvating agent may help to open up the cellulose structure but otherwise I see no reason why it would be essential. (And of course, acetic acid is a co- product of the reaction anyway.) J. McCormick
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