Journal of the Serbian Chemical Society 2000 Volume 65, Issue 10, Pages: 695-708
https://doi.org/10.2298/JSC0010695J
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Protonation of maleic and fumaric acid in aqueous sulfuric acid solutions
Jankovska Katica (Faculty of Metallurgy and Technology, Skopje, Macedonia)
Šoptrajanova Lidija (Faculty of Natural Sciences and Mathematics, Institute of Chemistry, Skopje, Macedonia)
Spirevska Ilinka (Faculty of Natural Sciences and Mathematics, Institute of Chemistry, Skopje, Macedonia)
The protonations of maleic and fumaric acid in an acidic medium (aqueous
solutions of sulfuric acid) were followed spectrophotometrically at room
temperature. The acid-base equilibria were characterised qualitatively and
quantitatively. The pKBH+ values were determined using the Hammett equation,
employing several acid functions in order to determine which of them
describes best the protonation process of the studied organic acids. The
thermodynamic pKBH+ values as well as those of the solvation parameters m,
m* and ф and of the thermodynamic protonation constants (or, rather, the
pKa,p values) were also defermined. The method of characteristic vector
analysis (CVA) was used to reconstruct the experimental spectra.
Keywords: maleic acid, fumaric acid, protonation, spectrophotometry