ON THE SOLVENT ISOTOPE EFFECT OF DEUTERIUM IN AQUEOUS ACID SOLUTIONS

Journal Article · Tue Jan 20 04:00:00 EST 1959 · Journal of the American Chemical Society (U.S.)

DOI:https://doi.org/10.1021/ja01511a003· OSTI ID:4241598

Purlee, E L

The Gross-Butler theory for the solvent isotope effect of deuterium on acid-catalyzed reaction rates in thermodynamic activity function, Q' (n), for proton and deuteron at 25 deg are derived from experimental data by using the correct value for the isotopic exchange equilibrium constant for D/sub 2/O-H/sub 2/O and by taking into account the apparent difference in free energy between (Cl/ sup -/) in D/sub 2/O and (Cl/sup -/) in H/sub 2/O. An independent check of the Q'(n)-function at 25 deg is obtained by applying the rule of the geometric mean to the distribution of hydrogen isotopes between lyonium ion and water. Values for the thermodynamic activity function, Q'(n) are calculated for application at temperatures other than 25 deg , and it is demonstrated that equilibrium constants and reaction rates observed at 0, 15, 18, 30, and 35 deg are well predicted by the Gross-Butler theory when values of the Q'(n)-function corresponding to the appropriate temperatures are used. The nature of deviations from the Gross-Butler rate equation is briefly discussed. It is noted that the acid-catalyzed inversion of sucrose and the acid-catalyzed hydrolysis of methyl acetate and ethyl formate show significant deviations from the theory. The complete failure of the Gross-Butler rate equation to predict the rates for the acid-catalyzed mutarotation of glucose indicates that this reaction does not proceed via a pre-equilibrium mechanism. (auth)

• Research Organization: Florida State Univ., Tallahassee
• Sponsoring Organization: USDOE
• NSA Number: NSA-13-017936
• OSTI ID: 4241598
• Journal Information: Journal of the American Chemical Society (U.S.), Journal Name: Journal of the American Chemical Society (U.S.) Vol. Vol: 81; ISSN JACSA
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

ACIDS
ANIONS
CATALYSIS
CHEMISTRY
CHLORIDES
DEUTERIUM
DEUTERONS
EQUATIONS
HEAVY WATER
HYDROGEN
HYDROLYSIS
ISOTOPE EFFECTS
ISOTOPIC EXCHANGE
MATHEMATICS
PROTONS
QUANTITY RATIO
REACTION KINETICS
SOLUTIONS
SOLVENTS
SUGARS
THERMODYNAMICS
WATER