The acidity and self-catalyzed lactonization of l-gulonic acid: Thermodynamic, kinetic and computational study
Kutus, B; Peintler, G; Buckó, Á; Balla, Z; Lupan, A; Attia, AAA; Pálinkó, I; Sipos, P
HERO ID
4943165
Reference Type
Journal Article
Year
2018
Language
English
PMID
| HERO ID | 4943165 |
|---|---|
| In Press | No |
| Year | 2018 |
| Title | The acidity and self-catalyzed lactonization of l-gulonic acid: Thermodynamic, kinetic and computational study |
| Authors | Kutus, B; Peintler, G; Buckó, Á; Balla, Z; Lupan, A; Attia, AAA; Pálinkó, I; Sipos, P |
| Journal | Carbohydrate Research |
| Volume | 467 |
| Page Numbers | 14-22 |
| Abstract | Lactonization and proton dissociation of sugar acids take place simultaneously in acidic aqueous solutions. The protonation-deprotonation processes are always fast, whilst the formation and hydrolysis of γ- and δ-lactones are usually slower. Thus, both thermodynamic and kinetic information are required for the complete understanding of these reactions. The protonation constant (Kp) of l-gulonate (Gul-) was determined from potentiometric and polarimetric measurements, while the individual lactonization constants (KL,γ and KL,δ) for l-gulonic acid (HGul) were obtained via13C NMR experiments. The applicability of this method was proven by measuring these well-known constants for d-gluconic acid (HGluc) and by comparing them to literature data. l-gulonic acid γ-lactone (γ-HGul) has remarkable stability in contrast with δ-HGul as well as γ- and δ-HGluc. The polarimetric measurement implies that the main factor responsible for the enhanced stability of γ-HGul is that its hydrolysis is much slower than that of δ-HGul. This higher stability of the γ-HGul ring over its δ-isomer was also confirmed by quantum chemical calculations. A new confirmed feature of the reaction is that in parallel to H3O+, HGul also catalyzes the formation and reverse hydrolytic processes of γ-HGul, similarly to other general acid catalysts. |
| Doi | 10.1016/j.carres.2018.07.006 |
| Pmid | 30048821 |
| Wosid | WOS:000441886200003 |
| Is Certified Translation | No |
| Dupe Override | No |
| Is Public | Yes |
| Language Text | English |