Abstrait

Comparison of rate constants for the Beckmann rearrangement reactions of syn and anti substituted benzaldoxims in perchloric acid

A.S.P.Azzouz*, B.D.Kashmola

Anti substituted benzaldoximes were prepared by a standard method, and their structures were confirmed by physical method, namely UV-IR spectra and melting points. The study deals with kinetic study for the Beckmann rearrangement reactions of anti isomers of benzaldoxime and its substitutents in perchloric acid as acidic catalyst. The reaction order was found to be of type pseudo first with respect to aldoxime.Aspectrophotometric method was used for the investigation of kinetic study. Rate constants for the Beckmann rearrangement reactions of anti isomeric of benzaldoximes were evaluated at temperatures range between (323-363)K and discussed. Finally a relative rate constants ksyn/kanti were evaluated at a temperature ranges mentioned and showmostly a relative values greater than unity in all aldoximeswith exception of 3-nitrobenzaldoxime. The cause for the last resultwas explained and discussed.