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Study of interactive free-energy relationships on ruthenium(III) catalyzed oxidation of phenyl styryl ketone and its substituted analogues by V(V) in acid medium

✍ Scribed by S. R. Annapoorna; M. Prasad Rao; B. Sethuram


Publisher
John Wiley and Sons
Year
2000
Tongue
English
Weight
130 KB
Volume
32
Category
Article
ISSN
0538-8066

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✦ Synopsis


Kinetics of Ru(III) catalyzed oxidation of phenyl styryl ketone (PSK) and its substituted analogues by V(V) has been investigated in aqueous acetic acid-sulphuric acid medium in the temperature range 298-313 K. First-order dependence each on [V(V)], [PSK], and [Ru(III)] was observed. Inverse first-order dependence was observed for [V(IV)]. The rate decreased with the increase in dielectric constant (D) of the medium. The rates were enhanced by electron-donating substituents in both the phenyl rings and decreased by electron-withdrawing substituents. Linear Hammett's plots were obtained for various substituents in benzaldehyde moiety of PSK for a given substituent in acetophenone moiety and vice versa. The mechanism proposed envisages formation of Ru(IV) from V(V) ϩ Ru(III) reaction followed by the attack on C " O by Ru(IV). Applicability of interactive free-energy relationship has been tested. The cross-interaction constants q x and q y have been determined at different temperatures and possible interpretations discussed.