Phase Equilibrium and Reaction-rate Control

These findings indicate that the control of phase behavior is one of the keys to controlling chemical reactions in near-critical fluids. Phase equilibrium plays an important role in dense fluid reaction systems, because the number of phases in equilibrium and their composition can be changed easily by pressure and temperature, and also as a consequence of the conversion of materials by chemical reactions. 

The role of phase equilibria on homogeneously catalyzed reactions in dense fluids was discussed by Buchmuller et al [13] in the palladium-catalyzed coupling reaction of butadiene and CO2 to form 6-lactone, as the main product. 

At a selected temperature of 60°C and a pressure of 60 bar, a two-phase mixture of 1,3-butadiene and CO2 exists, consisting of a liquid phase of 58 mol% CO2 and 

The effect of high-pressure CO2 on the melting point of a soHd compound - the gas-induced melting-point lowering - provides another method whereby phase equilibrium control may lead to enhanced reaction rates, coupled with easy separation of product from solvent. 

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