Autonomous reorganization of the oscillatory phase in the PdI2 catalyzed phenylacetylene carbonylation reaction
The PdI2 catalyzed oxidative carbonylation of phenylacetylene has been shown to produce pH oscillations over the temperature range 0 40 degC under semi batch conditions. The decrease in reaction temperature resulted in an increase in the period and amplitude of the pH oscillations. In addition, reducing the reaction temperature enabled the observation of different phases in the oscillatory pH behavior confirming the ability of the reaction system to autonomously produce multiple clusters of oscillatory phases. Sets of pH oscillations were recorded at 0 and 10 degC. At temperatures of 0 20 degC, oscillations commenced as pH was falling during the initial stages of the reaction while, at 30 and 40 degC, the oscillations commenced once the pH started to increase after the initial drop. Oscillations in turbidity were observed at 20 and 30 degC. Experiments were conducted in an HEL Simular reaction calorimeter enabling precise temperature control. Operating at 0 degC reduced the reaction rate prolonging the duration of pH oscillations. The oscillatory pH behavior was recorded for 11 days without additional substrate at which point the run was terminated although the oscillations would likely have continued.
Reaction Kinetics, Mechanisms and Catalysis