Heats of hydrolysis of N-methylformanilide dimethyl acetal have been m
easured in basic solution. The heat of formation of N-methylformanilid
e was obtained by determining the equilibrium constant in aqueous solu
tion for its formation from formic acid and N-methylaniline as a funct
ion of temperature: Delta H-f(0)(I) = -33.78 +/- 1.85 kcal/mol. These
data permit the calculation of the heat of formation of N-methylforman
ilide dimethyl acetal, Delta H-f(0)(I) = -72.95 +/- 1.85 kcal/mol. The
free energy of formation of the tetrahedral intermediate in the hydro
lysis of N-methylformanilide was calculated by methods we have previou
sly reported. Consideration of the energetics of the intermediates and
the known rates of reaction leads to the conclusion that the rate-det
ermining step for alkaline hydrolysis is cleavage of the C-N bond.