Liquid-vapor equilibrium data, density and other volumetric properties of carbon dioxide + acrylic acid binary mixtures at high pressure

JUAN MANUEL MILANESIO; SÉVERINE CAMY; SIMON HARRISON; MIRIAM STRUMIA; MATHIAS DESTARAC

Lisboa

Encuentro; 16th European Meeting on Supercritical Fluids (EMSF 2017); 2017

Facultad de Ciencias y Tecnología, Universidad Nueva de Lisboa

Acrylic acid is a polymerizable monomer with a dipole moment of 1.5 D while CO2 is a low dielectric constant solvent at high pressures. On the other hand, CO2 is a weak Lewis acid and has a significant quadrupole moment which contributes to its solubility in some polar solvents. In this work, Pressure vs Volume pseudo-continuous curves at constant temperature were determined in a variable volume high-pressure view cell, giving isoplethic isotherms in a wide range of pressures. With this raw experimental data, other properties were determined such as liquid-vapor boundaries, density, isothermal compressibility, isobaric expansivity, thermal pressure coefficient, and excess volumes for binary mixtures of CO2 + acrylic acid over a wide range of conditions. Densities were determined using a fully computerized variable-volume view-cell system capable of monitoring the position of the piston. The goal of this work is to study the phase behaviour and other volumetric properties of the reaction mixture during supercritical polymerization of acrylic acid. The maximum pressure recorded was 200 bar and the temperature ranged from 40 to 90 oC. The mole fraction of acrylic acid in the mixture was increased from 0.01 to 0.6. The liquid-vapor boundaries were in good agreement with data from the open literature. This work forms part of a wider project involving the copolymerization of acrylic acid and other co-monomers in compressed solvents.