World Journal of
Pharmaceutical and Life Sciences

EFFECT OF SUBSTITUENTS ON COOXIDATION RATE OF AROMATIC ANILS AND OXALIC ACID BY CHROMIC ACID

Yousif Algamal*

ABSTRACT

Though aromatic anils are said to be very sluggish towards Cr(VI) in presence of aqueous acetic acid medium, it can be easily oxidized in presence of oxalic acid, where it is proposed that an intermediate is formed between anil and a chromic acid –oxalic acid complex. The presence of the molecule of oxalic acid with in the complex facilitates the direct three electrons – reduction of Cr(VI) to Cr(III), which is the rate –limiting step, and the effect of various factors on rate of cooxidation were studied and reported earlier. The rate of oxidation was found to be a fractional order with respect anil and substituted anils, first order with respect to oxidant and fractional order with respect to oxalic acid. A number of substituted anils were prepared, purified and characterized and their effect on the cooxidation rate were studied at different five temperatures clearly shown that electron –releasing groups on both benzaldehyde and aniline moieties at the para position enhancing the rate of cooxidation whereas electronwithdrawing groups on both benzaldehyde and aniline moieties at para position retarding the rate of cooxidation. The thermodynamics parameters were computed and the isokinetic temperature computed from these plots is 502K.

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