73882-16-3Relevant academic research and scientific papers
Kinetics and Mechanism of Hydrolysis of a Silicate Triester, Tris(2-methoxyethoxy)phenylsilane
McNeil, K. J.,DiCaprio, J. A.,Walsh, D. A.,Pratt, R. F.
, p. 1859 - 1865 (2007/10/02)
The kinetics of hydrolysis in dilute aqueous solution of tris(2-methoxyethoxy)phenylsilane to phenylsilanetriol have been studied.The hydrolysis exibits specific acid and general base catalysis, the latter with a Broensted β value of 0.7.The specific acid catalysis mechanism is probably A-2 (kH3O+/D3O+ = 1.24, ΔS = -39 cal deg-1 mol-1).At high pH (>10) the rate of appearance of the triol is limited by the rate of hydrolysis of one of the intermediates in the hydrolysis sequence, bis(2-methoxyethoxy)phenylsilanol, which, under these conditions, forms an inert anion.At lower pH the hydrolysis of bis(2-methoxyethoxy)phenylsilanol is several times faster than that of tris(2-methoxyethoxy)phenylsilane while that of the second intermediate, 2-methoxyethoxyphenylsilanediol, is probably faster than the above two hydrolyses at all pHs.It is argued that the form of general base catalysis observed suggests that the base-catalyzed reactions involve either an SN2**-Si or SN2*-Si mechanism with formation of a pentacoordinate intermediate.Generalization of the argument used here is explored.
