ROLE OF COUNTER ANION IN ACID HYDROLYSIS OF GLYCOSIDES

摘要

Methyl α-D-glycopyranoside (MGPα) and methyl β-D-glycopyranoside (MGPβ) were hydrolyzed faster in 0.2 mol/L HBr than in 0.2 mol/L HCl and H2SO4 systems. The hydrolysis rates were slightly faster when KBr and KCl were added, respectively, to the above former two systems, which probably results from the higher ion strengths in the systems with the salts. However, the rate difference between the HBr and HCl systems cannot rationally be explained. The proton activities in these systems should be compared to evaluate this difference. If the proton activities are not the same, the role of Br- is to result in the higher proton activity. If the proton activities are the same, Br- is suggested to participate more significantly in the hydrolysis reactions.