An-Najah Staff

Oxidation of some alicyclic amines (morpholine, piperazine and piperidine) by potassium hexacyanoferrate(III) in basic medium has been investigated at 35°C. Stoichiometric results showed that four moles of hexacyanoferrate(III) were consumed per mole of piperidine or morpholine whereas piperazine consumed eight moles of the oxidant to produce the corresponding lactams. Kinetic studies indicated that piperidine and morpholine also followed different kinetics from that of piperazine, being first order in the amine concentration and independent of the concentrations of hexacyanoferrate(???) and hydroxide ion, while in the case of piperazine, the reaction was first order in both oxidant and substrate concentrations and zero order with respect to the concentration of hydroxide ion. The changes in reaction rate due to changing ionic strength of the medium as well as other factors has also been investigated. The activation parameters of the oxidation process have been evaluated and a mechanism consistent with the observed kinetics has been proposed. Keywords: Hexacyanoferrate(III), morpholine, piperazine, piperidine, oxidation, lactam.