CINETIQUE ET MECANISME DE LA REACTION DE KNOEVENAGEL DANS LE BENZENE-2 REACTION DU MALONITRILE ET DE LA (+) METHYL-3 CYCLOHEXANONE EN PRESENCE D'UNE AMINE PRIMARIE PURE ET DE SON MELANGE AVEC L'ACIDE ACETIQUE

Article abstract of DOI:10.1016/S0040-4020(01)91880-0

The kinetics of the reaction of (+)-3-methyl cyclohexanone with malonitrile were studied in benzene at 25 deg C, in the presence of hexylamine-acetic acid mixtures.Hexylamine gives an imine with cyclohexanone in an acid-catalyzed step.This imine then reacts quickly with malononitrile.A rate law of zero order in malononitrile is observed.Separate kinetic results obtained for the formation of the imine and for the imine-malonitrile reaction support this mechanism.Without acetic acid, a complex rate law is observed; hexylamine acts mainly as a basic catalyst.Primary amine-carboxylic acid was used as a catalyst in Knoevenagel reaction, often giving an increase in yield and a diminution in the reaction time compared with the more commonly used catalysts: piperidine, β-alanine, AcOH-AcONH4.