Cellulose with trifluoroacetic anhydride

H. Yuan, Y. Nishiyama, and S. Kuga, Surface esterification of cellulose by vapor-phase treatment with trifluoroacetic anhydride, Cellulose, 12 (2005) 543-549. 

Rapid acetylation of cellulose, during which, it is claimed, only about one bond per thousand D-glucose residues is broken, accompanies the use of a mixture of acetic anhydride and trifluoroacetic anhydride as the reaction medium. The preparation of a fibrous triacetate by treating cotton with acetic anhydride containing perchloric acid, as a catalyst, and amyl... 

The rate of acetylation of 0-(hydrox3Tnethyl)cellulose (and other hydroxy compounds) by mixtures of carboxylic acids and their anhydrides has been found to increase greatly in the presence of trifluoroacetic acid. The acceleration is very much less with mono- and tri-chloroacetic acids, presumably because they form unsymmetrical anhydrides which are less effective acylating agents than acyl trifluoroacetates. The exceptional acylating power of the latter anhydrides is shown by their use in the synthesis of alkyl aryl ketones from polyalkylbenzenes, phenyl ethers, furan, and thiophene under mild conditions. The principle has been extended to include acids... 

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