The Effect of Temperature on Selectivity in the Oscillatory Mode of the Phenylacetylene Oxidative Carbonylation Reaction.

Julie Parker,Katarina Novakovic

doi:10.1002/cphc.201700359

Abstract

Reaction temperature plays a major role in product selectivity in the oscillatory mode of the palladium‐catalyzed phenylacetylene oxidative carbonylation reaction. At 40 °C, dimethyl (2Z)‐2‐phenyl‐2‐butenedioate is the major product whereas at 0 °C the major product is 5,5‐dimethoxy‐3‐phenyl‐2(5H)‐furanone. The occurrence of oscillations in pH coincides with an increase in the rate of phenylacetylene consumption and associated product formation. Experiments were performed isothermally in a reaction calorimeter to correlate reactant consumption and product formation with the occurrence of pH oscillations and the heat released by the reaction. An increase in the size of the pH drop in a single oscillation correlates with an increase in energy, indicating that this section of a single oscillation relates to reactant consumption. Based on these observations, a reaction pathway responsible for product formation is provided.

Highlights

Reaction temperature plays a major role in product selectivity in the oscillatory mode of the palladium-catalyzed phenylacetylene oxidative carbonylation reaction
The influence of reaction temperature on the period and amplitude of pH oscillations during the Palladium-catalyzed phenylacetylene oxidative carbonylation (PCPOC) reaction was captured.[3d]. Isothermal experiments performed over the temperature range 10–50 8C demonstrated the existence of oscillations in the range 10–40 8C, with a decrease in reaction temperature resulting in an increase in the period and amplitude of the pH oscillations
The study presented here investigates the effect of the oscillatory mode of the PCPOC reaction on the dynamics of product formation over the temperature range of 0–40 8C

Summary

Introduction

Reaction temperature plays a major role in product selectivity in the oscillatory mode of the palladium-catalyzed phenylacetylene oxidative carbonylation reaction. The associated effect of reducing reaction temperature on product formation during the PCPOC reaction in oscillatory mode was not investigated.

Results

Conclusion