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Medium Effect on the Base-Catalysed Hydrolysis of Substituted Triphenylsilanes in Acetonitrile

✍ Scribed by J.-J. Tondeur; G. Vandendunghen; A. Borghese

Publisher: Wiley (John Wiley & Sons)
Year: 2010
Weight: 355 KB
Volume: 102
Category: Article
ISSN: 0037-9646
DOI: 10.1002/bscb.19931020503

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✦ Synopsis

The hydrolysis of some p-substituted triphenylsilanes in the presence of tetrabutylammonium hydroxide has been investigated in various water-acetonitrile media with the aim of comparing the results with those already published for triphenylsilane. It appears that the initial rate is first order with respect to both silane and base whereas the order during the time is not constant for some silanes, depending on the water composition. The second order rate constant varies in agreement with the Hammett substituent constant a,,. From the calculations of the transfer Gibbs functions for the activated state and for OH-from a reference medium (water mole fraction = 0.225), it is concluded that the solvent effect is not fundamentally altered by the p-substituents and that the medium influence on the rate can be essentially attributed to solvation modifications around OH-.

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