Ba(OH)2 as the catalyst in organic reactions. Part XIV. Mechanism of Claisen–Schmidt condensation in solid–liquid conditions

Abstract

The mechanism of the Claisen–Schmidt condensation, catalyzed by a series of activated barium hydroxide catalysts, is discussed. Two kinds of ketones are studied: R—CO—CH3 (R = Me, Et, Pri, But) and acetophenone (R = Ph). The influence of the chemical and textural properties of the catalysts, as well as the nature of the solvent, are studied. The process is an interfacial solid–liquid reaction between the adsorbed carbanion and the benzaldehyde. The different structures of the adsorbed carbanion produced from Ph—CO—CH3 and R—CO—CH3 are analyzed by infrared spectroscopy, and could explain the different reactivities observed in the process. The kinetic runs are discussed.