Kinetics of cyclohexene hydrocarbalkoxylation with cyclohexanol catalyzed by the Pd(PPh3)2Cl2-PPh3-p-toluenesulfonic acid system

The reaction kinetics of cyclohexene hydrocarbalkoxylation with cyclohexanol catalyzed by the Pd(PPh3)(2)Cl-2-PPh3-p-toluenesulfonic acid system was studied over the temperature range 363-393 K. The reaction rate was found to be a nonlinear function of the Pd(PPh3)(2)Cl-2 concentration or a nonmonotonic function of the PPh3 and cyclohexanol concentrations or p (CO). The experimental data were interpreted in terms of a mechanism that involves ion pairs containing alkyl and acyl palladium complexes of the cationic type as intermediates. Based on the quasi-steady-state approximation, a rate equation was obtained to adequately describe the experimental data. The rate equation parameters were estimated using the least squares technique. The apparent activation energies of these parameters were determined. The heats of formation of Pd(PPh3)(2)(C6H11OH)(2), Pd(PPh3)(2)(CO)(2), and Pd(PPh3)(4) complexes from Pd(PPh3)(2)(C6H5CH3)(2) were estimated. A symbatic change in these values with the donor-acceptor properties of ligands was demonstrated.