Aluminum Alkoxides as Synthons for Methylalumoxane (MAO):  Product-Catalyzed Thermal Decomposition of [Me2Al(μ-OCPh3)]2

The thermal decomposition of [Me2Al(μ-OCPh3)]2, to yield Ph3CMe and methylalumoxane ([MeAlO] n , MAO), is initially catalyzed by the addition of AlMe3; however, the reaction is also catalyzed by the MAO product. The overall reaction rate takes the form: rate = k TMA[{Me2Al(μ-OCPh3)}2][AlMe3] + k MAO[{Me2Al(μ-OCPh3)}2][MAO], where k MAO ≫ k TMA. The ΔH ⧧ for the AlMe3- and MAO-catalyzed reactions have been determined as 175 ± 8 and 190 ± 15 kJ·mol-1, respectively. Both reactions show a large positive value of ΔS ⧧ (41 ± 8 eu and