A. Inesi, L. Rampazzo
Jan 2, 1974
Citations
0
Influential Citations
14
Citations
Journal
Journal of Electroanalytical Chemistry
Abstract
Summary The electrochemical behaviour of fluoroacetic ethyl ester (I), fluoroacetic acid (II), difluoroacetic ethyl ester (III), difluoroacetic acid (IV), trifluoroacetic ethyl ester (V) and trifluoroacetic acid (VI) in DMF-Et4NClO4 solutions on a mercury cathode has been studied. All compounds except I are reducible. The esters show a one-electron, diffusion controlled, polarographic wave, with E1/2=−2.56 V (III) and E1/2=−2.36 V (V), with cleavage of the C-F bond. The reduction mechanism is discussed: electron transfer via the carbonyl function is suggested. In fluoroacetic acid (I) the hydrogen of the nearly undissociated molecule is reduced, E1/2=−2.29 V. In the case of difluoroacetic acid, two waves are observed, E1/2=−1.74 V and E1/2=−2.16 V respectively, the first one being kinetic in nature. Controlled potential experiments demonstrate that the first wave corresponds to the reduction of solvated proton, whereas the second wave is caused by the hydrogen reduction from the undissociated acid. Trifluoroacetic acid behaves as a moderately ‘strong’ acid in DMF and only the reduction wave of solvated proton is observed, E1/2=−1.48 V.