Hydrolysis Kinetics of 2-Pyridinecarboxamide, 3-Pyridinecarboxamide and 4-Pyridinecarboxamide in High-Temperature Water

A kinetic study is reported here on hydrolysis of three pyridinecarboxamides in high-temperature water in the temperature range of 190–250 °C 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.

Graphical abstractKinetic studies on hydrolysis of 2-pyridinecarboxamide, 3-pyridinecarboxamide and 4-pyridinecarboxamide in high-temperature water were carried out in the temperature range of 190–250 °C at 8 MPa. Experiments at different temperatures showed that the first-order rate constants displayed 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.Figure optionsDownload full-size imageDownload as PowerPoint slide