An ester formed from cellulose and ethanoic acid (acetic acid) used to make acetate fibres
Note: Purified cellulose is ethanoylated (acetylated) by ethanoic anhydride (acetic anhydride) in the presence of a catalyst (such as sulphuric acid or perchloric acid) in a solvent such as dichloromethane (methylene chloride) or ethanoic acid. The reaction proceeds until primary cellulose acetate containing 60% of combined ethanoic acid is formed. Secondary cellulose acetate is formed from the primary acetate by partial hydrolysis. It is obtained by adding water in excess of that required to react with the residual ethanoic anhydride, which thus allows the hydrolysis to take place.
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