The Kinetics of Mutarotation in Solution

The kinetics of the mutarotation of representative reducing sugars from the pentose, hexose and disaccharide series have been investigated polarimetrically over wide temperature ranges in aqueous solution. The dependence of the velocity coefficient, k, upon temperature is fairly well reproduced by an equation of the form ln k = C + (J/R) ln T - E/RT. The true energy of activation, E, is found to be some 6000 calories greater than the apparent value afforded by the Arrhenius equation at room temperature. J/R has a value of — 10, which is identified as the number of oscillators contributing to the activation. The constants C, J and E of this equation are discussed, with reference to many reactions, in terms of a theory of unimolecular reactions in solution.