Cellulose hydroxy alkyl ether

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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