Modeling liquid-vapor equilibrium and density data of carbon dioxide + acrylic acid binary mixtures at high pressure

MATÍAS MENOSSI; JUAN MANUEL MILANESIO; SÉVERINE CAMY; MIRIAM STRUMIA; MATHIAS DESTARAC

Ciudad Real

Congreso; 17th European Meeting on Supercritical Fluids (EMSF 2019); 2019

Universidad de Castilla - La Mancha

Supercritical CO2 (scCO2) can be used in polymer synthesis, as many monomers are soluble at relatively moderate conditions. It can solubilize low molecular weight non-polar molecules, slightly polar molecules, and even carboxylic acids. However, the synthesized polymers are typically insoluble in scCO2, precipitating from the reactive mixture. As an example, Poly(acrylic acid) (PAA) has been polymerized successfully by precipitation polymerization in a batch reactor and by continuous precipitation polymerization. One of the most important parameters for continuous polymerization is the density of the reactive mixture. The residence time and the flow rates of each component depend on the density of the reactive mixture. The main goal of this work is to provide experimental data of phase boundaries and liquid densities for the binary system ?CO2 + acrylic acid? and to correlate these data with a three-parameter cubic equation of state (3P-EOS). Pressure vs volume pseudo-continuous curves at constant temperature were determined in a variable volume high-pressure view cell, giving isoplethic isotherms in the liquid region over a wide range of pressures. Also, liquid-vapor equilibrium (LVE) data was measured. The experimental data was fitted using a cubic EOS that includes a third parameter. The RKPR EOS was developed in order to improve the representation of densities for different types of compounds, while maintaining the relative simplicity of cubic equations of state.