6533b838fe1ef96bd12a4f90
RESEARCH PRODUCT
The Dissociation Constant of Pyruvic Acid: Determination by Spectrophotometric Measurements
Peter WarneckMichael R. Fischersubject
Dissociation constantchemistry.chemical_compoundAqueous solutionSodium pyruvateChemistryStereochemistryGeneral Chemical EngineeringAttenuation coefficientAnalytical chemistryHydrochloric acidPyruvic acidIonDilutiondescription
Aqueous solutions of sodium pyruvate/hydrochloric acid mixtures were studied with regard to changes in the intensity of optical absorption at 317 nm wavelength, caused by varying pH and temperature. The data were evaluated to determine the pyruvic acid apparent dissociation constant at infinite dilution. Its temperature dependence followed the relation ln Kod = −(0.55 ± 0.47) − (1538 ± 135)/T or, if previous results of Pedersen at two temperatures are included, In Kod = −(0.97 ± 0.35) − (1418 ± 102)T. The effective absorption coefficient for pyruvic acid and its anion differ because the former species is largely hydrated, whereas the latter is not. The known hydration constant and its temperature dependence were used to derive the dissociation constant K1b for unhydrated pyruvic acid at infinite dilution. Its pK is 1.88 at 25°C with In K1d = −(8.67 ± 0.35) + (1296 ± 102)/T. The absorption coefficients for unhydrated pyruvic acid and its anion are essentially the same.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 1991-04-01 | Berichte der Bunsengesellschaft für physikalische Chemie |