Protonation of amides by trifluoroacetic acid: infrared and nuclear magnetic resonance studies
1973; Pergamon Press; Volume: 29; Issue: 4 Linguagem: Inglês
10.1016/0584-8539(73)80093-5
ISSN1873-3824
AutoresJoseph W.O. Tam, Irving M. Klotz,
Tópico(s)Molecular spectroscopy and chirality
ResumoN,N-dimethylacetamide and N-methylacetamide in mixtures of trifluoroacetic acid and carbon tetrachloride have been studied by i.r. spectroscopy in the region from 4000 to 2000 cm−1. The intensities of vOH of monomeric form as well as the associated form of trifluoroacetic acid decrease quantitatively upon amide addition. This is ascribed to the transfer of a proton from -COOH to the amide molecule. Nuclear magnetic resonance measurements have also been made for these amides in mixtures of organic acids, ranging from weak to very strong, and nonpolar solvents. The results show that not only trifluoroacetic acid but also dichloroacetic is capable of protonating the amide molecule.
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