Publication Details
Abstract
The kinetic and thermodynamic properties of six well-known Schiff bases (A1, A3, A5, A6, A8, A12) derived from 4-aminoantipyrine and six different aromatic aldehydes were studied. The substituent on aldehydic ring of the compounds ranged from electron-withdrawing to electron donating substituents, in addition to benzaldehyde itself. The hydrolysis kinetics of the Schiff bases revealed minimal disparity in their rate constant values. Faster rate of hydrolysis was observed in the case of (A5) comparing with the remaining compounds. The effect of an acidic pH on the hydrolysis process is in line with earlier research and studies, indicating that conducting the reaction in acidic or basic environments, as opposed to a neutral environment, speeds up the process. An investigation into the effect of temperature on the hydrolysis of the examined compounds revealed that the activation energy values for all compounds were quite low. This indicates that the reaction occursreadily and rapidly. The ΔG values indicated that the hydrolysis processes of the compounds under investigation did not proceed spontaneously, but were instead facilitated by the presence of a catalyst, specifically hydrogen and hydroxyl ions. The investigation verified the significance of the thermodynamic variables (∆H and ∆S) in regulating reaction rates. Additionally, the calculated negative entropy value suggests a probable formation of the activated active complex.