- ISOSELECTIVITY RELATION IN THE SOLVOLYSIS OF SUBSTITUTED TRITYL AND m-CHLOROTRITYL BENZOATES IN AQUEOUS ETHANOL
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The rate constants for the solvolysis of two series of trityl benzoates XC6H4(C6H5)2COC(O)C6H4Y in aqueous ethanol (80-100percent) were determined by potentiometric titration, and the activation and correlation parameters were calculated.In series (I) the effect of the substituent Y on the reaction rate in 100percent ethanol is due to entropic control.The isoselectivity temperature (Tis) lies in the region of 25 deg C.An inverse relation between the reactivity and selectivity (ρ, m) is observed when T > Tis, and this is regarded as the consequence of the predominance of solvation effects, which appear at the stage of the transition from intimate to loose ion pairs, over electronic effects.In the more reactive series (II) the effect of solvation decreases, the activation parameters level out, and the Tis value becomes less than the determined value.
- Karavan, V. S.,Eliseeva, E. E.
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p. 657 - 662
(2007/10/02)
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