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Lookup NU author(s): Dr Julie Parker,
Dr Katarina Novakovic
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The dynamics of reactant consumption and product formation in the oscillatory mode of the palladium-catalysed phenylacetylene oxidative carbonylation reaction over the temperature range of 0–40 °C were studied. Experiments were performed isothermally in a reaction calorimeter to correlate reactant consumption and product formation with the occurrence of oscillations and the heat released by the reaction. Reactant and products were quantified using GC-MS analysis. The dynamics of reactant and product formation throughout the course of the reaction (several days) were recorded. Oscillations in pH and accompanying pulses of heat were captured. The increase in period and amplitude of the pH oscillations that occurs as temperature decreases was found to continue at 0 °C. The reaction heat was released in a pulsatile manner, resulting in a stepwise increase in the total energy released with the steps in energy being correlated with the pH oscillations. As the size of the pH oscillations increased, the amount of energy released during each step increased. It was also found that product selectivity changed with temperature: at 40 °C dimethyl (2Z)-2-phenyl-2-butenedioate was the major product whereas at 0 °C the major product was 5,5-dimethoxy-3-phenyl-2(5H)-furanone. The clear temperature dependence of the conversion rates as well as an increase in conversion as oscillations in pH developed were documented and an explanation for this behaviour is offered. In addition, a reaction pathway associated with selective formation of the observed products is proposed and aligned with the observed oscillatory phenomena. 1. Novakovic, K., et al., The influence of reaction temperature on the oscillatory behaviour in the palladium-catalysed phenylacetylene oxidative carbonylation reaction. Physical Chemistry Chemical Physics, 2009: p. 9044-9049.
Author(s): Parker J, Novakovic K
Publication type: Conference Proceedings (inc. Abstract)
Publication status: Published
Conference Name: XXXVII Dynamics Days Europe International Conference
Year of Conference: 2017
Online publication date: 05/06/2017
Acceptance date: 10/05/2017