Kinetic Studies of Condensation of Aromatic Aldehydes with Meldrum’s Acid

Abstract

The condensation reaction of Meldrum’s acid with aromatic aldehydes in the presence of a catalyst has been investigated spectrophotometrically at 25-50 °C. The reaction follows overall second order kinetics, first order in each of the reactants. Electron-withdrawing groups accelerate and electron-releasing groups retard the rate of condensation. From the dependence of the rate constants on temperature, the activation parameters have been calculated and also the isokinetic temperature with a value of 403.5 K. Based on this reaction, determination of eight aromatic aldehydes in a concentration range of 1.49 - 91 μg/ml is proposed. On the other hand, determination of some aromatic aldehydes with Meldrum’s acid is performed in water at 75 °C for 2 h, without adding any catalyst.