The dependence of the rate of the cyclohexene hydrocarbomethoxylation reaction catalyzed by the Pd(PPh3)(2)Cl-2-PPh3-p-toluenesulfonic acid system on the CO pressure and methanol concentration at temperatures varied in the range of 358-388 K has been investigated. The data are interpreted in terms of the previously proposed mechanism involving as intermediates ion pairs containing cationic hydride, alkyl, and acyl palladium complexes. By the least squares technique, apparent constants relating to the effect of CO pressure and methanol concentration have been estimated for the rate equation derived earlier. The apparent activation energies have been determined for these constants, and the following stability series of palladium complexes has been proposed on their basis: Pd(PPh3)(2)(CO)(2) > Pd(PPh3)(4) > Pd(PPh3)(2)(CH3OH)(2) > HS(circle plus)ol[Pd(PPh3)(2)(Cl)(Sol)](circle minus).