A kinetic study is reported here on hydrolysis of three pyridinecarboxamides in high-temperature water in the temperature range of 190-250℃ at 8 MPa. 2-Pyridinecarboxamide

3-pyridinecarboxamide and 4-pyridinecarboxamide hydrolyze to corresponding picolinic acids. 2-Picolinic acid is further decarboxylated to pyridine. Experiments at different temperatures show that the first-order rate constants display an Arrhenius behavior with activation energies of (110.9 ± 2.3)

(70.4 ± 2.1) and (61.4 ± 1.8) kJ·mol

-1

for 2-pyridinecarboxamide

3-pyridinecarboxamide and 4-pyridinecarboxamide

respectively. These kinetic parameters for pyridinecarboxamide hydrolysis are more reliable and accurate than those from the consecutive hydrolysis of cyanopyridines.