Original scientific paper
https://doi.org/10.5281/zenodo.3267263
Protonation of citraconic and glutaconic acid in perchloric acid media
Milena Jankulovska-Petkovska
orcid.org/0000-0002-3581-558X
; Ss Kliment Ohridski University, Faculty of Veterinary Medicine in Bitola, Macedonia
Mirjana S. Jankulovska
orcid.org/0000-0002-3581-558X
; Ss. Cyril and Methodius University, Faculty of Agricultural Sciences and Food in Skopje, Macedonia
Vesna Dimova
orcid.org/0000-0001-5062-7600
; Ss Cyril and Methodius University, Faculty of Technology and Metallurgy in Skopje, Macedonia
Abstract
The protonation process of citraconic and glutaconic acid in perchloric acid media was followed using the method of UV spectroscopy. The observed changes in the UV spectra of investigated acids confirmed that the protonation process in perchloric acid with concentration from 5 to 10 mol/dm3 occurred. Glutaconic acid behaved as weak organic base in perchloric acid media and existed in its monoprotonated form. On the other hand, citraconic acid existed in its protonated form and as protonated anhydride at higher perchloric acid concentration. Using the absorbance data the thermodynamic dissociation constants were calculated applying the methods of Yates and McClelland, Bunnett and Olsen, and the “excess acidity” function method. The solvatation parameters m, m* and were evaluated, as well. In order to correct the medium effect the method of characteristic vector analysis was applied. The possible site where the protonation may take place was discussed using the partial atomic charge values determined according to AM1 and PM3 semiempirical methods.
Keywords
citraconic acid; glutaconic acid; UV spectroscopy; thermodynamic dissociation constants; AM1 and PM3 semiempirical methods
Hrčak ID:
222399
URI
Publication date:
5.7.2019.
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