Addition de l'Hexafluoroacétone sur les Acides Carboxyliques—Mise en Évidence par RMN 1H et 19F. Application à l'Analyse d'un Mélange d'Acides

The compound HO? C(CF₃)₂? O₂CR results from nucleophilic addition of a carboxylic acid to the carbonyl group of hexafluoroacetone. I.r. and n.m.r. (¹H, ¹⁹F) spectroscopy have been used to show that the addition is reversible. The addition is favoured by a lowering of the temperature and by the use of acids in which the group R is electron donating. Moreover, the chemical shift of the CF₃ groups (or of the OH group) in the addition product is dependent on the nature of R. Thus, this reversible addition can be used as a method for the analysis of a mixture of carboxylic acids by n.m.r. spectroscopy.