Solvent Isotope Effect of Pyruvic Acid Hydration

Abstract

AbstractThe solvent isotope effect on the hydration constant, the dissociation constant and the rate constants for the uncatalysed and specific acid catalysed dehydration of pyruvic acid is investigated. The pK of the dissociation constant of the ketoacid is by 0.29 smaller in H2O than in D2O. The ratio of the hydration constant of undissociated pyruvic acid (K/K) is 0.83, while the ratio of the rate constant of dehydration is 2.65 for the uncatalysed reaction and 1.33 for lyonium ion catalysis. The results are discussed in terms of the possibility of intramolecular hydrogen bonding.