Kinetic Investigation of the Claisen–Schmidt Reaction: Mechanochemistry Versus Conventional Solution Method

ABSTRACT For the first time, the kinetics of the Claisen–Schmidt condensation reaction have been investigated under mechanochemical conditions. The reaction between 5‐bromo‐2‐hydroxyacetophenone and 3,4,5‐trimethoxybenzaldehyde using a modified vibratory ball mill was studied and compared with the same reaction carried out in methanol. Mechanochemistry has shown several advantages over solution chemistry, including higher yields, shorter reaction times, lower energy consumption, and greater environmental sustainability, positioning it as a promising approach for green chemistry. In the solid state, the influence of various parameters, such as the material, diameter, and mass of the grinding ball, as well as the temperature, was investigated. The kinetic study revealed that the reaction under mechanochemical conditions is highly dependent on temperature. Specifically, for experiments carried out at temperatures above 30°C, the reaction follows an apparent zero‐order kinetic model, whereas below 30°C, a second‐order model better fits the data. Activation energies for the solid phase and solution reactions were determined.