Abstract
Abstract The kinetics of oxidation of aromatic anils to benzaldehyde and azobenzene by magnesium monoperoxyphthalate (MMPP) has been studied in aqueous acetic acid medium. The low dielectric constant of the medium facilitates the reactivity. It has been found that ionic strength of the reaction has no significant effect on rate. The added acrylonitrile has no effect on the reaction rate indicating the absence of free radical mechanism. The added Mn(II) decreases the rate of the reaction, which indicates the involvement of two-electron transfer. Highly negative ΔS# values indicate a structured transition state. The deviation of Hammett plot is noted and a non-linear concave downward curve is obtained for the anils with substituents in the aniline moiety. The observed break in the log kobs versus σ is attributed to the transition state whereas the non-linear concave upward curve is observed for the substituents in the benzaldehyde moiety and a non-linear concacve upward curve is observed for the substituents in the combination of aniline and benzaldehyde moiety and a suitable mechanism is proposed
Highlights
magnesium monoperoxyphthalate (MMPP) is a commercially available, inexpensive and relatively stable oxidant
We report simple and effective approaches for the selective aromatic anils using MMPP in organic solvents
Literature survey reveals that no report is available on the kinetics of oxidation of meta- and para- substituted aromatic anils with MMPP; this study has considered it worthwhile to do research on the kinetics and mechanism of oxidation of anils by MMPP
Summary
MMPP is a commercially available, inexpensive and relatively stable oxidant. Since its development in the early 80 s, it has been used in the oxidation of various functional groups[1, 2], for instance, in the epoxidation of alkenes, sulfur and nitrogen oxidations, Baeyer-Villiger oxidation[1, 3] as well as in the oxidative cleavage of hydrazones[3]. Anils are prepared[12] by refluxing equimolar quantities of benzaldehyde and aniline (Sigma Aldrich) in ethanol for about 2 to 3 h. After 24 h, the acetic acid is neutralized and the reaction mixture ethanol is extracted. Formation of the azobenzene is confirmed by UV-visible spectra [λmax 429 nm] of the reaction solution during and after the completion of the reaction. This was in agreement with the literature value[14]. The oxidation reactions of meta- and para- substituents of aromatic anils are studied at different temperatures (298, 303, 308, 313 and 318K) to evaluate various thermodynamic parameters.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
