Chemical reactions approaching demixtion of multicomponent systems(ABSTRACT)

摘要

We propose here a study of coupling between demixtion and chemical reaction. The studied system is composed of two liquid phases (water - 2-pentanol). The phase diagram is well-known. The addition of carboxylic acid (for instance butyric acid) in the aqueous phase starts a chemical reaction, producing an ester. These species diffuse nearly kindred in the two phases.Like that the liquid phase is modified by decreasing of the butyric acid and by increasing of the ester which have others proprieties. The alcohol phase is also modified by apparition of the ester.The concentrations are adapted to cause the demixtion. The system is studied on approaching the demixtion. Eventual instability and the phase diagram are determined. We compare this with a phase diagram of the same system without reaction. Either by stopping the reaction (adding an inhibitor, adjusting the concentrations, or modifying the temperature) or by subsisting the butyric acid by a similar but no reactive molecule (like a butane aldehyde).The study allows reaching a better comprehension of the thermodynamic of the organic components in the multi-component system. It will generate precise inputs of the comportment of organic molecules at the phase change. Theses inputs are a basis for the study about oil problems like asphalthenes [1]