LAUSR

Abstract The effect of the polar head and the concentration of quaternary ammonium surfactants (C 14 EtOH, C 14 iPrOH, C 14 PrOH, where, 14 = carbon number iPrOH = iso-propanol, EtOH = ethanol, PrOH = propanol) in micellar catalysis for the cross-condensation reaction (Claisen–Schmidt) was investigated. The reaction in the Micellar - NaOH system with different concentrations of surfactants above the critical micelle concentration from 15 to 30 mmol between benzaldehyde and acetophenone was used as a model of reaction for this study. The examination of the effectiveness of the catalytic activity reveals that the compound C 14 EtOH has the best yield (80% of the desired product), followed by C 14 iPrOH and C 14 PrOH. The results were interpreted according to the solubilization capacity, droplet size analysis of reagents (benzaldehyde and acetophenone) in the micellar medium and stability of reaction intermediate (enolate) by the electrostatic interactions generated by positive charge of N + quaternary ammonium atom. Therefore, the quantum calculations carried out by DFT method for surfactants in the aqueous medium, show that electrophilicity degree and the reaction yield% for three cationic surfactants varies in the same following order: C 14 PrOH < C 14 iPrOH < C 14 EtOH. Graphic Abstract